Proposed Rule2026-02575
Hazardous Materials: Harmonization With International Standards
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Published
February 10, 2026
Issuing agencies
Transportation DepartmentPipeline and Hazardous Materials Safety Administration
Abstract
PHMSA proposes to amend the Hazardous Materials Regulations to adopt certain international regulations and standards related to proper shipping names, hazard classes, packing groups, special provisions, packaging authorizations, air transport quantity limitations, and vessel stowage requirements. These amendments are intended to maintain consistency with the latest international standards and regulations, and to reduce costs to entities or individuals within the United States or to otherwise lower the cost of regulations on the United States economy.
Full Text
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[Federal Register Volume 91, Number 27 (Tuesday, February 10, 2026)]
[Proposed Rules]
[Pages 5996-6071]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-02575]
[[Page 5995]]
Vol. 91
Tuesday,
No. 27
February 10, 2026
Part II
Department of Transportation
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Pipeline and Hazardous Materials Safety Administration
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49 CFR Parts 171, 172, 173, et al.
Hazardous Materials: Harmonization With International Standards;
Proposed Rule
Federal Register / Vol. 91 , No. 27 / Tuesday, February 10, 2026 /
Proposed Rules
[[Page 5996]]
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DEPARTMENT OF TRANSPORTATION
Pipeline and Hazardous Materials Safety Administration
49 CFR Parts 171, 172, 173, 175, 176, 178, and 180
[Docket No. PHMSA-2023-0111 (HM-215R)]
RIN 2137-AF64
Hazardous Materials: Harmonization With International Standards
AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA),
Department of Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: PHMSA proposes to amend the Hazardous Materials Regulations to
adopt certain international regulations and standards related to proper
shipping names, hazard classes, packing groups, special provisions,
packaging authorizations, air transport quantity limitations, and
vessel stowage requirements. These amendments are intended to maintain
consistency with the latest international standards and regulations,
and to reduce costs to entities or individuals within the United States
or to otherwise lower the cost of regulations on the United States
economy.
DATES: Comments must be received by April 13, 2026. To the extent
possible, PHMSA will consider late-filed comments while a final rule is
developed.
ADDRESSES: You may submit comments by any of the following methods:
<bullet> Federal Rulemaking Portal: <a href="http://www.regulations.gov">http://www.regulations.gov</a>.
Follow the online instructions for submitting comments.
<bullet> Fax: 1-202-493-2251.
<bullet> Mail: Docket Management System; U.S. Department of
Transportation, Docket Operations, M-30, Ground Floor, Room W12-140,
1200 New Jersey Avenue SE, Washington, DC 20590-0001.
<bullet> Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, Ground Floor, Room W12-140, 1200 New Jersey Avenue
SE, Washington, DC 20590-0001 between 9 a.m. and 5 p.m., Monday through
Friday, except Federal holidays.
Instructions: Include the agency name and docket number PHMSA-2023-
0111 (HM-215R) or RIN 2137-AF64 for this rulemaking at the beginning of
your comment. All comments received will be posted without change to
<a href="http://www.regulations.gov">http://www.regulations.gov</a>, including any personal information
provided. If sent by mail, comments must be submitted in duplicate.
Persons wishing to receive confirmation of receipt of their comments
must include a self-addressed stamped postcard.
Docket: For access to the dockets to read background documents
including the Preliminary Regulatory Impact Analysis (PRIA) or comments
received, go to <a href="http://www.regulations.gov">http://www.regulations.gov</a> or DOT's Docket Operations
Office (see ADDRESSES).
Confidential Business Information: Confidential Business
Information (CBI) is commercial or financial information that is both
customarily and actually treated as private by its owner. Under the
Freedom of Information Act (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments in response to this NPRM contain
commercial or financial information that is customarily treated as
private, that you actually treat as private, and that is relevant or
responsive to this NPRM, it is important that you clearly designate the
submitted comments as CBI. Pursuant to 49 CFR 105.30, you may ask PHMSA
to provide confidential treatment to the information you give to the
agency by taking the following steps: (1) mark each page of the
original document submission containing CBI as ``Confidential;'' (2)
send PHMSA a copy of the original document with the CBI deleted along
with the original, unaltered document; and (3) explain why the
information you are submitting is CBI. Submissions containing CBI
should be sent to Steven Andrews, 1200 New Jersey Avenue SE, DOT:
PHMSA-PHH-10, Washington, DC 20590-0001. Any comment PHMSA receives
that is not explicitly designated as CBI will be placed in the public
docket.
FOR FURTHER INFORMATION CONTACT: Candace Casey, Standards and
Rulemaking, at 202-366-8553, Pipeline and Hazardous Materials Safety
Administration, U.S. Department of Transportation, 1200 New Jersey
Avenue SE, East Building, 2nd Floor, Washington, DC 20590-0001.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Executive Summary
II. Background
III. Incorporation by Reference Discussion Under 1 CFR Part 51
IV. Amendments Not Being Proposed for Adoption
V. Section-by-Section Review of NPRM Proposals
VI. Regulatory Analyses and Notices
A. Legal Authority
B. Executive Order 12866; Regulatory Planning and Review
C. Executive Orders 14192 and 14219
D. Energy-Related Executive Orders 13211, 14154, and 14156
E. Executive Order 13132: Federalism
F. Regulatory Flexibility Act
G. Unfunded Mandates Reform Act of 1995
H. National Environmental Policy Act
I. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
J. Privacy Act
K. Paperwork Reduction Act
L. Executive Order 13609 and International Trade Analysis
M. National Technology Transfer and Advancement Act
N. Cybersecurity and Executive Order 14028
O. Severability
I. Executive Summary
The Secretary of Transportation is directed by 49 U.S.C. 5120 to
ensure that domestic regulations for the transportation of hazardous
materials are generally consistent with the latest international
standards and requirements, unless such standards or requirements are
unnecessary or unsafe, or a more stringent safety standard is in the
public interest. Consistent with this statutory requirement, the
Pipeline and Hazardous Materials Safety Administration proposes to
amend the Hazardous Materials Regulations (HMR) to adopt certain
international regulations and standards, including changes to material
incorporated by reference, hazardous materials descriptions and proper
shipping names (PSN), hazard classes, packing groups (PG), special
provisions, packaging authorizations, air transport quantity
limitations, and vessel stowage requirements.
PHMSA anticipates that the adoption of the amendments proposed in
this NPRM will maintain the current levels of safety achieved under the
HMR. Harmonizing the HMR with international consensus standards is
expected to also reduce delays and interruptions in the transportation
of hazardous materials and promote the efficient and free flow of
commerce by eliminating unnecessary, outdated, and conflicting
regulatory requirements. Overall, the proposed amendments are intended
to reduce costs to entities or individuals within the United States or
otherwise lower the cost of regulations on the United States economy.
The following list summarizes noteworthy proposals set forth in
this NPRM:
<bullet> Incorporation by Reference: PHMSA proposes to incorporate
by reference updated versions of the following international hazardous
materials regulations and standards: the 2025-2026 edition of the
International
[[Page 5997]]
Civil Aviation Organization Technical Instructions for the Safe
Transport of Dangerous Goods by Air (ICAO Technical Instructions);
Amendment 42-24 to the International Maritime Dangerous Goods Code
(IMDG Code); the 2023 edition of Transport Canada's Transportation of
Dangerous Goods (TDG) Regulations; and the 23rd revised edition of the
United Nations Recommendations on the Transport of Dangerous Goods--
Model Regulations (UN Model Regulations).
<bullet> Amendments to the Hazardous Materials Table: PHMSA
proposes amendments to the Hazardous Materials Table (HMT; Sec.
172.101) to add, to revise, or to remove certain PSNs, hazard classes,
PGs, SPs, packaging authorizations, bulk packaging requirements, and
passenger and cargo aircraft maximum quantity limits.
<bullet> Increase in authorized amounts of certain gases
transported as limited quantities: For modes other than air
transportation, PHMSA proposes to extend the relief provided by the
limited quantity provisions to four Division 2.2 (non-flammable and
non-poisonous) compressed gases. This amendment would authorize these
materials for transport as a limited quantity material in quantities up
to 1000 ml (34 fluid ounces) per package, when transported in DOT
specification cylinders or UN pressure receptacles. These materials
are: ``UN1006, Argon,'' ``UN1013, Carbon dioxide,'' ``UN1046, Helium,''
and ``UN1066, Nitrogen.''
<bullet> Amendments to the Organic Peroxides Table: PHMSA proposes
amendments to the organic peroxides table in Sec. 173.225, which lists
individual organic peroxide formulations that are authorized for
transportation without prior approval. The proposed amendments include
the addition of three new formulations: (Dibenzoyl peroxide, 2,5-
dimethyl-2,5-di-(tert-butylperoxy) hexane, and methyl ethyl ketone
peroxide (with a concentration limit of available oxygen <=10 percent),
that will no longer require prior approval when transported under the
conditions outlined in the table, as well as the addition of a new
authorized packaging for Di-(3,5,5-trimethylhexanoyl) peroxide, not
more than 52 percent, stable dispersion, in water.
<bullet> Amendments to provisions for the transport of
tetramethylammonium hydroxide: PHMSA proposes to adopt several changes
pertaining to entries for Tetramethylammonium hydroxide (TMAH) to
maintain consistency with changes adopted in several international
standards in response to new incident and test data showing a toxicity
hazard in addition to the previously identified corrosivity hazard. The
proposed amendments include the addition of a new HMT entry for aqueous
solutions, and revisions to the hazard classification, proper shipping
name, or both, for existing entries of PG II and PG III TMAH solutions
(UN1835), reclassification of TMAH solids (UN3423), the addition of two
new special provisions, and revised packaging authorizations.
<bullet> New provisions for sodium ion batteries: PHMSA proposes to
add new HMT entries and transport provisions for sodium ion batteries
to maintain consistency with changes adopted in the 2025-2026 edition
of the ICAO Technical Instructions and the 23rd revised edition of the
UN Model Regulations. The new provisions in the international
regulations regulate sodium ion batteries in the same way as lithium
ion batteries and are intended to address anticipated increases in the
use of sodium ion batteries as an alternative to lithium ion batteries.
<bullet> New state-of-charge provisions for certain lithium and
sodium ion batteries transported by air: PHMSA proposes expanding
current state-of-charge requirements to certain lithium and sodium ion
batteries transported by air. The new provision would limit the amount
of stored energy to 30 percent or less of the battery's capacity at the
time of transport.
<bullet> Improved Emergency Response Information for Lithium
Batteries Transported as ``UN3536, Lithium batteries installed in cargo
transport unit lithium ion batteries or lithium metal batteries: ''
PHMSA proposes to amend Special Provision 389 to require that the
emergency response information for UN3536 specifically identify the
predominant type of energy storage battery installed in the unit (e.g.,
lithium ion batteries or lithium metal batteries) and provide
information on immediate methods for handling fires. When determining
the predominant type of energy storage battery, PHMSA encourages
shippers to consider which battery type provides electrical power to
external devices or the power grid when units transported under UN3536
are in operation.
<bullet> Exceptions for ammonium nitrate hot concentrated solution:
PHMSA proposes to add specific conditions under which solutions of
ammonium nitrate (hot concentrated solution) can be transported under
the HMT entry ``UN2426, Ammonium nitrate'' or can qualify for exception
from regulation under the HMR. The proposed requirements for solutions
of ammonium nitrate to be transported under UN2426 are based on
concentration, water content, combustible material content, chlorine
content, pH level, and temperature. These requirements were adopted in
the 23rd revised edition of the UN Model Regulations to harmonize
transport conditions and requirements multimodally.
<bullet> Exceptions for nitrocellulose membrane filters used in
rapid test devices: PHMSA proposes to add a new special provision with
specific packaging requirements for ``UN3270, Nitrocellulose membrane
filters, with not more than 12.6% nitrogen, by dry mass'' to be
excepted from regulation. These materials are most notably used in
rapid test devices for infectious diseases and as substrates for
bioanalytical tests as well as pregnancy tests. PHMSA's proposal would
maintain consistency with changes adopted in the 23rd revised edition
of the UN Model Regulations to facilitate further the transport of
these items.
PHMSA anticipates that the proposals in the NPRM will produce
safety benefits from harmonizing domestic and international
regulations. PHMSA solicits comment on the need, benefits, and costs of
the proposed HMR revisions; impact on safety and the environment; and
any other relevant information. PHMSA also solicits comment regarding
approaches to reducing the costs of the proposed HMR revisions while
maintaining or increasing safety benefits and on any other specific
changes (e.g., greater flexibility regarding a particular proposal)
that might improve the rulemaking. As further explained in the PRIA,
PHMSA expects that the aggregate benefits of the amendments proposed in
this NPRM for United States entities or individuals justify their
aggregate costs.
II. Background
The Federal Hazardous Materials Transportation Law (49 U.S.C. 5101,
et seq.) directs PHMSA to participate in international standard-setting
forums for the transportation of hazardous materials in commerce and
encourages alignment of the HMR with those standards (49 U.S.C. 5120).
Harmonization of the HMR with international standards and regulations
can reduce the costs and other burdens of complying with multiple or
inconsistent safety requirements between nations.
PHMSA actively participates in the development of international
standards for the transportation of hazardous materials and promotes
the adoption of standards consistent with the HMR. Maintaining
consistency between
[[Page 5998]]
current international standards and the HMR enhances safety by, among
other things: (1) ensuring the HMR are informed by the latest
international best practices and lessons learned; (2) improving
understanding of, and compliance with, pertinent international
requirements; (3) facilitating the flow of hazardous materials in
commerce and avoiding risks to the public and the environment from
handling and potential releases of hazardous materials due to delays or
interruptions in transportation; and (4) enabling consistent emergency
response procedures in the event of a hazardous materials incident.
When considering alignment of the HMR with new or amended
international standards, PHMSA reviews each standard on its own merit,
assesses its overall impact on transportation safety, and analyzes the
economic implications associated with its adoption. PHMSA's goal is to
harmonize with international standards without diminishing the level of
safety currently provided by the HMR or imposing undue burdens on the
regulated community.
In 1990, PHMSA's predecessor, the Research and Special Programs
Administration (RSPA), comprehensively revised the HMR for greater
consistency with the UN Model Regulations.\1\ The UN Model Regulations
constitute a set of recommendations issued by the United Nations Sub-
Committee of Experts (UNSCOE) on the Transport of Dangerous Goods and
on the Globally Harmonized System of Classification and Labelling of
Chemicals (GHS). The UN Model Regulations are amended and updated
biennially by the UNSCOE and serve as the basis for national, regional,
and international modal regulations, including the ICAO Technical
Instructions and IMDG Code. PHMSA routinely updates the HMR to
incorporate these biennial amendments.
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\1\ 55 FR 52401 (\De\c. 21, 1990).
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PHMSA has evaluated the latest biennial updates to the
international regulations and consensus standards and proposes to
revise the HMR to adopt changes consistent with revisions to the 2025-
2026 edition of the ICAO Technical Instructions, the Amendment 42-24 to
the IMDG Code, and the 23rd revised edition of the UN Model
Regulations, all of which were published by or in effect on January 1,
2025.\2\ PHMSA also proposes to incorporate by reference these revised
international regulations, as well as several new or updated
International Organization for Standards (ISO) standards. The
regulations incorporated by reference are authorized for use for
domestic and international transportation, under specific conditions,
in part 171, subpart C of the HMR.
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\2\ Amendment 42-24 of the IMDG Code became mandatory on January
1, 2025. Voluntary compliance began on January 1, 2024.
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On December 9, 2024, PHMSA issued a notice of enforcement
discretion, stating that PHMSA and other Federal agencies that enforce
the HMR (i.e., the Federal Railroad Administration (FRA), the Federal
Aviation Administration (FAA), the Federal Motor Carrier Safety
Administration (FMCSA), and the United States Coast Guard (USCG)) will
not take enforcement action against any offeror or carrier who follows
the 2025-2026 Edition of the ICAO Technical Instructions and Amendment
42-24 of the IMDG Code when all or part of the transportation is by air
with respect to the ICAO Technical Instructions, or all or part of the
transportation is by vessel with respect to the IMDG Code, during the
pendency of this rulemaking proceeding.\3\ For transport by rail and
highway to, from, or within the United States, PHMSA also stated that
these agencies will not take enforcement action against any offeror or
carrier who offers or accepts hazardous materials identified and
described on a shipping paper, or packages either marked or labeled in
accordance with these standards--provided that appropriate emergency
response information consistent with 49 CFR part 172, subpart G
accompanies the shipment. The December 9, 2024, notice of enforcement
discretion remains in effect until withdrawn or otherwise modified.\4\
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\3\ PHMSA, Notice of Enforcement Policy Regarding International
Standards (Dec. 9, 2024), available at: <a href="https://www.phmsa.dot.gov/regulatory-compliance/phmsa-guidance/notice-enforcement-policy-regarding-international-standards">https://www.phmsa.dot.gov/regulatory-compliance/phmsa-guidance/notice-enforcement-policy-regarding-international-standards</a>.
\4\ PHMSA notes that items described and packaged for
transportation under the respective international standards as
UN0514 and UN3559, ``Fire Suppressant Dispersing Devices,'' must
first be approved by the Associate Administrator in accordance with
49 CFR 173.56.
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III. Incorporation by Reference Discussion Under 1 CFR Part 51
The National Technology Transfer and Advancement Act of 1995
(NTTAA; Pub. L. 104-113) directs Federal agencies to use standards
developed by voluntary consensus standards bodies in lieu of
government-written standards whenever possible. Voluntary consensus
standards bodies develop, establish, or coordinate technical standards
using agreed-upon procedures. PHMSA currently incorporates by reference
into the HMR all or parts of numerous standards and specifications
published by these bodies, which are otherwise known as standard
development organizations (SDOs). In general, SDOs update and revise
their published standards every two to five years to reflect modern
technology and best technical practices.
The Office of Management and Budget (OMB) issued Circular A-119,
Federal Participation in the Development and Use of Voluntary Consensus
Standards and in Conformity Assessment Activities, to implement Section
12(d) of the NTTAA. This circular provides guidance for Federal
agencies participating in voluntary consensus standards bodies and
describes procedures for satisfying the reporting requirements in the
NTTAA. PHMSA is responsible for determining which standards currently
referenced in the HMR should be updated, revised, or removed, and which
standards should be added to the HMR, under the NTTAA and Circular A-
119.
Revisions to materials incorporated by reference in the HMR are
handled via the notice-and-comment rulemaking process. PHMSA must also
obtain approval from the Office of the Federal Register to incorporate
by reference any new materials during that process. The Office of the
Federal Register issued a rulemaking that revised 1 CFR 51.5 to require
that an agency detail in the preamble of an NPRM the ways the materials
it proposes to incorporate by reference are reasonably available to
interested parties, or how the agency worked to make those materials
reasonably available to interested parties.\5\ Proposed changes to the
material incorporated by reference in the HMR are discussed in detail
in the Section 171.7 discussion in ``Section V. Section-by-Section
Review of NPRM Proposals.''
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\5\ 79 FR 66278 (Nov. 7, 2014).
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The standards incorporated by reference in this NPRM are reasonably
available to interested parties in several ways. The UN Model
Regulations and the United Nations Manual of Tests and Criteria (UN
Manual of Tests and Criteria) are free and easily accessible to the
public on the internet (links are provided in footnotes as part of the
section 171.7 discussion in ``Section V. Section-by-Section Review of
NPRM Proposals'').\6\ The ICAO Technical
[[Page 5999]]
Instructions, the IMDG Code, and all ISO standard references are
available for interested parties to purchase, either in print or
electronic versions through the organizations' websites. In addition,
all standards that PHMSA proposes to incorporate by reference in the
NPRM will be available for review, free of charge, at the PHMSA
Headquarters, 1200 New Jersey Avenue, SE, Washington, DC 20590 during
the comment period. Interested persons may email <a href="/cdn-cgi/l/email-protection#9cfffdf2f8fdfff9b2fffdeff9e5dcf8f3e8b2fbf3ea"><span class="__cf_email__" data-cfemail="abc8cac5cfcac8ce85c8cad8ced2ebcfc4df85ccc4dd">[email protected]</span></a>
to arrange for this in-person review.
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\6\ United Nations, UN Model Regulations 23rd revised edition,
(October 8, 2023), available at: <a href="https://unece.org/transport/dangerous-goods/un-model-regulations-rev-24">https://unece.org/transport/dangerous-goods/un-model-regulations-rev-24</a>; United Nations, Manual
of Tests and Criteria, Eighth revised edition (November 27, 2023),
available at: <a href="https://unece.org/transport/standards/transport/dangerous-goods/un-manual-tests-and-criteria-rev8-2023">https://unece.org/transport/standards/transport/dangerous-goods/un-manual-tests-and-criteria-rev8-2023</a>.
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IV. Amendments Not Being Proposed for Adoption
PHMSA has determined that certain elements of updated international
regulations and standards should not be adopted into the HMR (49 U.S.C.
5120). PHMSA has also determined that certain transport requirements
should be authorized on a case-by-case basis through special permits
rather than adopting them for general applicability in the HMR.
Additional information about these topics is provided below:
<bullet> Additional regulation for carbon and charcoal--The
International Maritime Organization (IMO), through its Sub-Committee on
Carriage of Cargoes and Containers (CCC), adopted more stringent
requirements than currently exist in the HMR for the transport of
carbon (e.g., activated carbon or carbon derived from animal or
vegetable origin) in Amendment 42-24 to the IMDG Code. Most notably,
the IMO removed the ability to exclude such carbon materials from
classification as a Division 4.2 (spontaneously combustible material),
i.e., a self-heating material, by way of testing, and consequently the
ability to be transported as unregulated.
Section 173.124 of the HMR currently requires carbon materials such
as charcoal that are potentially spontaneously combustible because of
self-heating properties to be tested by performing UN Test N.4, ``Test
method for self-heating substances,'' in accordance with the UN Manual
of Tests and Criteria (see Section 33.4.3.3) and either classified as a
Division 4.2 material or excluded from regulation. This classification
or exclusion applies to both bulk and non-bulk (e.g., charcoal packaged
for retail sale) quantities of carbon. Materials meeting classification
criteria are described as ``UN1361, Carbon, animal or vegetable
origin'' or ``UN1362, Carbon, activated'', Division 4.2, and are
subject to packaging requirements for bulk and non-bulk quantities,
respectively. See Sec. Sec. 173.212 and 173.242 for PG II and
Sec. Sec. 173.214 and 173.241 for PG III. In addition, hazardous
materials transported under UN1361 and UN1362 are assigned stowage
category ``A'', meaning that these materials may be stowed ``on deck''
or ``under deck'' on a cargo or passenger vessel, and that they must be
kept as cool as reasonably practicable and protected from sources of
heat. These stowage requirements in the HMR are in alignment with the
current requirements under Amendment 42-24 of the IMDG Code. In the
absence of safety incidents related to the shipment of these materials,
as well as the unlikelihood of unpackaged bulk shipments of carbon
materials such as charcoal, PHMSA finds that the current requirements
in the HMR provide the appropriate level of safety without imposing
unnecessary burdens on transportation.
More specifically, Amendment 42-24 removed Special Provision 925
from the IMDG Code, which previously provided a blanket exception for
non-activated carbon blacks of mineral origin, consignments of carbon
that passed tests for self-heating substances UN Test N.4, and carbons
produced by a steam activation process. Amendment 42-24 also removed
packing provision PP12, which previously authorized the use of bags as
packaging for materials transported in closed cargo transport units,
for ``UN1361, Carbon.'' In addition, Amendment 42-24 removed Special
Provision 223--which was previously applicable to carbon materials
assigned to PG III--and permitted substances (except for marine
pollutants) covered by the description ``UN1361, Carbon, PG III'' or
``UN1362, Activated carbon, PG III'' to be excepted from the IMDG Code
when testing showed that the substances did not meet the established
defining criteria for any hazard class or division. Amendment 42-24
replaced Special Provisions 925 and 223 with a new Special Provision
978, which specifically prohibits the use of the UN N.4 test to except
carbon from the IMDG Code by limiting its application only to carbon
produced by pyrolysis of an organic material such as bone, bamboo,
coconut shell, jute, or wood. Special Provision 978 also requires
additional precautions, such as a 14-day weathering period and periodic
monitoring, while the material is stowed during transport. These
changes also impacted the stowage requirements for materials
transported in bulk containers with the aim of facilitating the
dissipation and removal of accumulated heat generated by large amounts
of densely stowed charcoal.
The IMO adopted the changes in Amendment 42-24 of the IMDG Code
following incidents caused by spontaneous combustion of unpackaged bulk
shipments of charcoal on board several vessels. The IMO concluded that
removing Special Provisions 223 and 925 was needed because these
special provisions could not be applied properly across all shipments
given that charcoal is often manufactured at different remote
production sites (charcoal piles) and consignments are often comprised
of charcoal from different origins with different properties rather
than being manufactured under standardized conditions.
PHMSA is not proposing to incorporate the changes adopted in
Amendment 42-24 of the IMDG Code. While largely aimed at addressing
fires associated with the movement of unpackaged bulk shipments of
charcoal, the current IMDG Code requirements also apply to smaller
packages of charcoal, such as those available for commercial retail use
(i.e., charcoal used for grilling). PHMSA believes that adopting these
IMO requirements would unnecessarily burden manufacturers with new
testing, handling, and packaging requirements for consumer products,
particularly given the lack of domestic incidents and unlikelihood that
unpackaged bulk shipments of carbon materials are being transported to
and from the U.S.
PHMSA also disagrees with the IMDG Code prohibition on the use of
UN Test N.4 to classify or exclude self-heating materials. PHMSA is not
aware of any safety concerns or domestic safety incidents that justify
the prohibition of the use of this test and believes that harmonizing
the HMR with these particular sections of the IMDG Code would impose
undue burdens for packaging and handling of carbon material without
producing a corresponding safety benefit. Because shipments packaged in
accordance with the IMDG Code are authorized for transport in the
United States under Sec. 171.22, PHMSA does not anticipate any
commercial or economic hardships will result from failing to adopt
these requirements.
<bullet> Marking and labeling for battery powered vehicles--The
23rd revised edition of the UN Model Regulations and Amendment 42-24 of
the IMDG Code adopted a new special provision, Special Provision 405,
for battery powered vehicles (``UN3556, Vehicle, lithium ion battery
powered,'' ``UN3557, Vehicle, lithium metal battery
[[Page 6000]]
powered,'' and ``UN3558, Vehicle, sodium ion battery powered'').
Special Provision 405 provides an exception for battery powered
vehicles from marking and labeling requirements when not fully enclosed
by packagings, crates, or other means that prevent ready
identification, thereby requiring marking and labeling when fully
enclosed by packaging, crates, or other means that prevent ready
identification. Special Provision 405 is similar to an existing Special
Provision A87 in the ICAO Technical Instructions. Special Provision A87
applies to articles but was assigned to battery powered vehicles in the
2024-2025 edition.
PHMSA is not proposing to adopt Special Provision 405 due to
concerns raised in various international working groups regarding the
necessity of the additional marking and labeling requirements. PHMSA
believes that these requirements, which would require new marks and
labels on a wide variety of popular consumer goods--e.g., lawn mowers,
scooters, motorcycles, wheelchairs--should be subject to further
evaluation. PHMSA seeks comments regarding the potential benefits of
additional hazard communication requirements for battery powered
vehicles transported in fully enclosed packagings.
<bullet> Non-removable specification markings--The 23rd revised
edition of the UN Model Regulations and the 2025-2026 ICAO Technical
Instructions states that UN specification markings must be placed on a
non-removable component of the packaging. A transitional exception
allows packagings to continue to be marked as required prior to the
adoption of the new requirement until December 31, 2026, and for any
packagings marked in such manner prior to January 1, 2027, to be
permitted for continued use. PHMSA anticipates determining that the
transitional exception is unnecessary as the HMR already includes such
a requirement in Sec. 178.3(a), which states that packagings
manufactured to a DOT specification or a UN standard must be marked
with the proper specification marking on a non-removable component of
the packaging. However, PHMSA seeks comments regarding the potential
need for a similar transitional exception. Note that section 178.503(a)
also applies the same requirement in Sec. 178.3(a) to the marking of
performance-oriented packagings.\7\
---------------------------------------------------------------------------
\7\ This requirement was added in rulemaking HM-218. 65 FR 50450
(Aug. 18, 2000).
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V. Section-by-Section Review of NPRM Proposals
The following is a section-by-section review of proposed amendments
to harmonize the HMR with international regulations and standards.
Part 171
Section 171.6
Section 171.6 of the HMR provides information on the OMB control
numbers assigned to information collections under the Paperwork
Reduction Act of 1995. The paragraph (b)(2) table lists the HMR
sections associated with each OMB control number. As this NPRM proposes
to add new information collection requirements to HMR, PHMSA proposes
to revise this table to include the section references where this new
information collection request is specified. See paragraph (K), under
the ``Regulatory Analyses Notices'' section for additional details
regarding new information collection requests.
Section 171.7
Section 171.7 provides a listing of all consensus standards and
regulations incorporated by reference into the HMR. PHMSA is proposing
to add or revise the following references in Sec. 171.7 in this NPRM:
\8\
---------------------------------------------------------------------------
\8\ All other standards that are set out as part of the
regulatory text of Sec. 171.7(w) were previously approved for
incorporation by reference and no changes are proposed.
---------------------------------------------------------------------------
<bullet> The 2023 edition of the American National Standards
Institute (ANSI) N14.1-2023, Nuclear Materials--Uranium Hexafluoride--
Packagings for Transport in paragraph (d)(8), which is currently
referenced in Sec. 173.420. This standard provides criteria for
packagings used for transport of uranium hexafluoride (UF6). It
includes specific information on design and fabrication requirements
for the procurement of new packagings intended for the transportation
of UF6 in quantities of 0.2205 lb. (0.1 kg) or more. It also defines
the requirements for in-service inspections, cleanliness, and
maintenance for packagings in service. Packagings currently in service
and not specifically defined in this standard will continue to be
authorized for use, provided they are used within their original design
limitations, and are inspected, tested, and maintained to comply with
the intent of this standard. This standard also includes requirements
for cylinder loading, shipping, and valves, plugs, and valve
protectors. PHMSA evaluated this updated standard and believes that the
revisions provide an enhanced level of safety without imposing
significant compliance burdens. This standard has a well-established
and documented safety history, and the adoption of the 2023 edition is
expected to maintain the safety standard currently achieved under the
HMR. The 2023 edition of ANSI N14.1 is available for purchase on the
ANSI website at: <a href="https://webstore.ansi.org/standards/pcc/ansin142023?source=blog">https://webstore.ansi.org/standards/pcc/ansin142023?source=blog</a>.
<bullet> The 2025-2026 edition of the ICAO Technical Instructions
in paragraph (t)(1) to replace the 2023-2024 edition, which is
currently referenced in Sec. Sec. 171.8; 171.22-24; 172.101; 172.202;
172.401; 172.407; 172.512; 172.519; 172.602; 173.56; 173.320; 175.10,
175.33; and 178.3. The ICAO Technical Instructions specify detailed
instructions and requirements for the international safe transport of
dangerous goods (i.e., hazardous materials) by air. The 2025-2026
edition has been amended to align with the 23rd revised edition of the
UN Model Regulations. Notable changes include new packing and stowage
provisions, new and revised entries on its Dangerous Goods List, and
editorial corrections. The 2025-2026 edition of the ICAO Technical
Instructions is available for purchase on the ICAO website at <a href="https://store.icao.int/en/shop-by-areas/safety/dangerous-goods">https://store.icao.int/en/shop-by-areas/safety/dangerous-goods</a>.
<bullet> The 2024 edition of the IMDG Code (Amendment 42-24) in
paragraph (v)(2) to replace Incorporating Amendment 41-22, which is
currently referenced in Sec. Sec. 171.22; 171.23; 171.25; 172.101;
172.202; 172.203; 172.401; 172.407; 172.502; 172.519; 172.602; 173.21;
173.56; 176.2; 176.5; 176.11; 176.27; 176.30; 176.83; 176.84; 176.140;
176.720; 176.906; 178.3; and 178.274. The IMDG Code is a unified
international code that outlines standards and requirements for the
transport of dangerous goods (i.e., hazardous materials) by sea (i.e.,
by vessel). Notable changes in Amendment 42-24 of the IMDG Code include
new packing and stowage provisions, new and revised entries on its
Dangerous Goods List, and editorial corrections. Distributors of the
IMDG Code can be found on the IMO website at: <a href="http://www.imo.org/en/publications/Pages/Distributors-default.aspx">www.imo.org/en/publications/Pages/Distributors-default.aspx</a>.
<bullet> The following ISO documents to add new and updated
standards for the specification, design, construction, testing, and use
of gas cylinders in paragraph (w):
--ISO 535:2014, Paper and board--Determination of water
absorptiveness--Cobb method in paragraph (w)(1). PHMSA proposes to
[[Page 6001]]
remove the 1991 version of this document, ISO 535:1991, which is
currently referenced in Sec. Sec. 178.707, 178.708, and 178.516, and
to incorporate by reference the 2014 edition, ISO 535:2014 in its
place. ISO 535:2014 specifies a method of determining the water
absorptiveness of sized paper and board, including corrugated
fiberboard, under standard conditions. This revised version contains
changes to the introduction, annexes, and bibliography. The 23rd
revised edition of the UN Model Regulations replaced the second edition
with the third edition, and PHMSA proposes to mirror these changes for
consistency. Replacing the 1991 version will allow references to
updated annexed information and bibliographies, as well as for
harmonization with other international standards, such as the 23rd
revised edition of the UN Model Regulations, in which references to ISO
535:1991 have also been removed.
--ISO 9809-4:2021, Gas cylinders--Design, construction and testing of
refillable seamless steel gas cylinders and tubes--Part 4: Stainless
steel cylinders with an R m value of less than 1 100 MPa in paragraph
(w)(40). PHMSA proposes to incorporate by reference the second edition
of this document, 9809-4:2021, and phase out the usage of the first
edition, 9809-4:2014, by adding a sunset date of December 31, 2028.\9\
These documents are to be referenced in Sec. Sec. 178.71 and 178.75.
ISO 9809-4:2021 specifies the minimum requirements for the materials,
design, construction and workmanship, manufacturing processes,
examinations and testing at time of manufacture for refillable,
seamless, stainless steel gas cylinders with water capacities up to and
including 150 L (i.e., ~40 gal.). As part of its regular periodic
review process, ISO updated 9809-4:2014 and published the second
edition, 9809-4:2021. The second edition includes changes to the
requirements for inspection and testing, clarifications of drawings of
the cylindrical parts of shells in Figure 3, and the addition of a new
provision pertaining to shear stress calculations.
---------------------------------------------------------------------------
\9\ The sunset dates proposed for adoption in this NPRM are
consistent with the phaseout date adopted in the 23rd revised
edition of UN Model Regulations.
---------------------------------------------------------------------------
--ISO 11114-1:2020, Gas cylinders--Compatibility of cylinder and valve
materials with gas contents Part 1: Metallic materials in paragraph
(w)(51). PHMSA proposes to remove the second edition of this document,
ISO 11114-1:2012, and the 2017 supplemental amendment, ISO 11114-
1:2012/Amd 1:2017, currently residing in paragraphs (w)(50) and
(w)(51), respectively, and referenced in Sec. Sec. 172.102, 173.301b,
and 178.71, and to replace these references with the updated third
edition, ISO 11114-1:2020. This document provides requirements for the
selection of safe combinations of metallic cylinder and valve materials
and cylinder gas contents. This revised third edition includes all
changes that were added in ISO 11114-1:2012/Amd.1:2017, clarification
of the definition of the term ``dry,'' clarification in the table of
compatibility, and various editorial improvements including updated
references to incorporate Amendment 1.
--ISO 11114-2:2021, Gas cylinders--Compatibility of cylinder and valve
materials with gas contents--Part 2: Non-metallic materials in
paragraph (w)(52). PHMSA proposes to remove the second edition of this
document, ISO 11114-2:2013, which is currently referenced in Sec. Sec.
173.301b and 178.71, and replace that reference with the third edition,
published in 2021. This document provides instruction on the selection
and evaluation of compatibility between non-metallic materials for gas
cylinders and valves and gas contents. It also applies to tubes,
pressure drums, and bundles of cylinders. The third edition has been
technically revised to include an update to Table 1 to include new non-
metallic materials, and a new Table 2, which addresses non-metallic
lining materials for gas cylinders.
--ISO 11119-1:2020, Gas cylinders--Design, construction and testing of
refillable composite gas cylinders and tubes--Part 1: Hoop wrapped
fibre reinforced composite gas cylinders and tubes up to 450 l in
paragraph (w)(62). PHMSA proposes to incorporate by reference the third
edition of this document in Sec. Sec. 178.75 and 178.71. The second
edition, ISO 11119-1:2012, is currently referenced in these sections.
PHMSA proposes to add a sunset date of December 31, 2028, on the use of
the second edition. This document is Part 1 in a three-part series.
Part 1 specifies minimum requirements for the material, design,
construction and workmanship, manufacturing processes, examination and
testing at time of manufacture for certain Type 2 composite hoop
wrapped gas cylinders or tubes intended for the storage and conveyance
of compressed or liquefied gases, as well as cylinders and tubes with
composite reinforcement of carbon fiber, aramid fiber or glass fiber
(or a mixture thereof) within a matrix of steel wire with a minimum
design life of 15 years. The most significant changes in the revised
edition of Part 1 include: updates and corrections to references
throughout the document; the addition of minimum fiber stress ratios;
changes to the fire resistance test procedure; and newly added criteria
for tubes above 150 L.
--ISO 11119-2:2020, Gas cylinders--Design, construction and testing of
refillable composite gas cylinders and tubes--Part 2: Fully wrapped
fibre reinforced composite gas cylinders and tubes up to 450 l with
load-sharing metal liners'' in paragraph (w)(66). PHMSA proposes to
incorporate by reference the third edition of this document in
Sec. Sec. 178.75 and 178.71. The second edition and a required
supplemental amendment, 11119-2:2012/Amd.1:2014, are currently
referenced in these sections. PHMSA proposes to add a sunset date of
December 31, 2028, on the use of these two documents, and to
incorporate by reference the third edition, ISO 11119-2:2020. This
document is Part 2 in a three-part series. Part 2 specifies minimum
requirements for the material, design, construction and workmanship,
manufacturing processes, examination and testing at time of manufacture
for Type 3 fully wrapped cylinders or tubes with a load-sharing metal
liner and composite reinforcement on both the cylindrical portion and
the dome ends. The most significant changes in the third edition of
Part 2 include: updated references; the addition of minimum fiber
stress ratios; the addition of a new alternative for the drop test for
certain cylinders; the addition of an alternative impact test for tubes
150 L or more; changes to fire resistance test procedure to make the
test more consistent; and changes to the torque test.
--ISO 11119-3:2020, Gas cylinders--Design, construction and testing of
refillable composite gas cylinders and tubes--Part 3: Fully wrapped
fibre reinforced composite gas cylinders and tubes up to 450 l with
non-load-sharing metallic or non-metallic liners or without liners in
paragraph (w)(69). PHMSA proposes to incorporate by reference the third
edition of this document in Sec. Sec. 178.71 and 178.75. The second
edition, 11119-3:2013, is currently referenced in these sections. PHMSA
also proposes to add a sunset date of December 31, 2028, on the use
[[Page 6002]]
of the second edition. ISO 11119-3:2020 specifies requirements for
composite gas cylinders up to 150 L water capacity and composite tubes
above 150 L water capacity and up to 450 L water capacity, for the
storage and conveyance of compressed or liquefied gases. This document
is Part 3 in a three-part series. Part 3 specifies minimum requirements
for the material, design, construction and workmanship, manufacturing
processes, examination and testing at time of manufacture for Type 4
composite fully wrapped cylinders or tubes with a non-load sharing
liner and composite reinforcement on both the cylindrical portion and
the dome ends, and Type 5 fully wrapped cylinders or tubes without
liners and with a test pressure of less than 60 bar, with water
capacities up to 450 L. This document is intended for cylinders used
for the storage and conveyance of compressed or liquefied gases;
cylinders and tubes with composite reinforcement of carbon fiber,
aramid fiber or glass fiber (or a mixture thereof) within a matrix; and
for cylinders or tubes with a minimum design life of 15 years. The most
significant changes in the third edition of part 3 include: the
addition of a new alternative for the drop test for cylinders up to and
including 50 L water capacity with dedicated compressed gas service;
the addition of alternative impact test for tubes 150 L or more;
changes to the fire resistance test procedure to make the test more
consistent and the addition of a criterion for tubes above 150 L;
changes to the torque test; and a new procedure for the pneumatic cycle
test. ISO revised the 2020 editions of ISO 11119 Parts 1, 2, and 3
following comments received from regulators, manufacturers, and users
of the standards worldwide. These changes were made to improve and to
clarify test procedures, particularly in relation to large composite
cylinders and tubes.
--ISO 15105-1:2007, Plastics--Film and sheeting--Determination of gas-
transmission rate Part 1: Differential-pressure methods in paragraph
(w)(82). PHMSA proposes to reference this document in Special Provision
43 in Sec. 172.102 as a part of a condition for exception from the HMR
for nitrocellulose membrane filters. This document specifies two
methods for determining the gas transmission rate of single-layer
plastic film or sheet and multi-layer structures under a differential
pressure.
--ISO 16148:2016/Amd 1:2020, Gas cylinders--Refillable seamless steel
gas cylinders and tubes--Acoustic emission examination (AT) and follow-
up ultrasonic examination (UT) for periodic inspection and testing--
Amendment 1 in paragraph (w)(86). PHMSA proposes to incorporate by
reference Amendment 1 of ISO 16148 into Sec. 180.207 to supplement ISO
16148:2016. Amendment 1 is a short two-page supplemental correction for
ISO 16148:2016, which gives procedures for the use of acoustic emission
examination and follow-up ultrasonic examination during the periodic
inspection and testing of seamless steel cylinders and tubes used for
compressed and liquefied gases with a water capacity of up to 3,000 L.
The use of this supplemental amendment would be required as this
document includes a significant correction of Note 2 to Figure A.1
concerning the calculation of the depth of the notches used for
calibration. PHMSA expects that the additional requirement to use this
supplemental amendment will improve safety by requiring the use of
improved engineering standards.
--ISO 23826:2021, Gas cylinders--Ball valves--Specification and testing
in paragraph (w)(97). PHMSA proposes to incorporate by reference the
first edition of this document into Sec. Sec. 178.301b and 178.71. ISO
23826:2021 is a new standard specifying the design, type testing,
marking, manufacturing tests and examination requirements for ball
valves used as closures of refillable transportable gas cylinders,
pressure drums, and tubes; main valves for cylinder bundles and valves
for cargo transport units and multiple element gas containers (MEGCs)
that convey compressed gases, liquefied gases, and dissolved gases. The
new document fills an important gap as ball valves are explicitly
excluded in other closure standards such as ISO 10297, Gas cylinders--
Refillable gas cylinder valves--Specification and type testing. PHMSA
expects that the addition of this reference document will facilitate
the manufacture, design, and testing of various packagings used for the
transport of hazardous materials.
All ISO standards can be found at: <a href="http://www.iso.org/standards.html">www.iso.org/standards.html</a>.
<bullet> The 2023 Edition of Transport Canada's Transportation of
Dangerous Goods (TDG) Regulations in paragraph (bb)(1), to replace the
2017 edition, which is currently referenced in Sec. Sec. 107.801;
107.805; 171.12; 171.22; 171.23; 172.401; 172.407; 172.502; 172.519;
172.602; 173.31; 173.32; 173.33; 173.301; 180.205; 180.211; 180.212;
and 180.413. Like the HMR, the TDG regulations provide requirements for
transportation of hazardous materials goods and activities relating to
road, rail, air, and marine transport into, from, and within Canada.
This paragraph lists 22 Statutory Orders and Regulations (SORs), which
have since been consolidated into one point of reference, SOR/2001-286.
PHMSA also proposes to remove references to these 22 SORs and only
reference SOR/2001-286 for all of Transport Canada's TDG regulations.
Transport Canada's TDG regulations are available online at: <a href="https://laws-lois.justice.gc.ca/eng/regulations/sor-2001-286/">https://laws-lois.justice.gc.ca/eng/regulations/sor-2001-286/</a>.
<bullet> The 23rd Revised Edition (2023) of the United Nations
Recommendations on the Transport of Dangerous Goods--Model Regulations
(UN Model Regulations), Volumes I and II, in paragraph (dd)(1), to
replace the 22nd revised edition (2021), which are referenced in
Sec. Sec. 171.8; 171.12; 172.202; 172.401; 172.407; 172.502; 172.519;
173.22; 173.24; 173.24b; 173.40; 173.56; 173.192; 173.302b; 173.304b;
178.75; 178.274. The UN Model Regulations present a basic scheme of
provisions that allow uniform development of national and international
regulations governing the various modes of transport. Amendments
adopted in the 23rd revised edition of the UN Model Regulations include
new UN numbers and provisions regulating the transport of sodium ion
batteries, fire suppressant dispersing devices, disilane, gallium
contained in articles, and trifluoromethyl tetrazole-sodium salt in
acetone; a new special provision to increase the authorized volume for
transport in limited quantities of some compressed gases of Division
2.2 without subsidiary hazards; more specific concentration limits for
ammonium nitrate hot concentrated solutions; exceptions for
nitrocellulose membrane filters; and an update to the requirements for
the use of recycled plastics in packagings. The 23rd revised edition of
the UN Model Regulations is available online at: <a href="https://unece.org/transport/dangerous-goods/un-model-regulations-rev-23">https://unece.org/transport/dangerous-goods/un-model-regulations-rev-23</a>.
<bullet> The 8th Revised Edition of the United Nations
Recommendations on the Transport of Dangerous Goods, Manual of Tests
and Criteria, in paragraph (dd)(2), to replace the 7th Revised Edition,
which is currently referenced in Sec. Sec. 171.24, 172.102; 173.21;
173.56; 173.57; 173.58; 173.60; 173.115; 173.124; 173.125; 173.127;
173.128; 173.137; 173.185; 173.220; 173.221; 173.224; 173.225; 173.232;
173, appendix H; 175.10; 176.905; and
[[Page 6003]]
178.274. PHMSA also proposes to add a new reference to this document in
Sec. 173.169 in reference to the performance of test series 6(c) for
fire suppressant dispersing devices. The UN Manual of Tests and
Criteria contains standards, test methods, and procedures to be used
for the classification of hazardous materials according to the UN Model
Regulations. Amendments adopted in this eighth revised edition include:
the addition of organic peroxides and polymerizing substances to the
list of substances that should not be tested in the self-heating test
to avoid false positives; a recommendation to use close-cup tests over
open-cup tests for determining flash points; new provisions for the
testing of sodium ion batteries; amendments to the classification of
desensitized explosives according to the Globally Harmonized System of
Classification and Labelling of Chemicals. The eighth revised edition
of the UN Manual of Tests and Criteria is available online at: <a href="https://unece.org/transport/standards/transport/dangerous-goods/un-manual-tests-and-criteria-rev8-2023">https://unece.org/transport/standards/transport/dangerous-goods/un-manual-tests-and-criteria-rev8-2023</a>.
<bullet> The 10th Revised Edition of the Globally Harmonized System
of Classification and Labelling of Chemicals (GHS), in paragraph
(dd)(3), to replace the 9th Revised Edition, which currently is
referenced in Sec. 172.401. The GHS is an international system
standardizing hazard classification and communication. The HMR
authorizes its use for labeling of packages. This revised edition
contains updates addressing, among other items, further rationalization
of precautionary statements to improve user comprehensibility while
considering usability for labelling practitioners. PHMSA notes that the
classification procedures for desensitized explosives that were added
in this edition of the GHS are not related to transport classification
and do not represent a requirement or criteria for obtaining an
approval under the HMR. The 10th revised edition of the GHS is
available online at: <a href="https://unece.org/transport/dangerous-goods/ghs-rev10-2023">https://unece.org/transport/dangerous-goods/ghs-rev10-2023</a>.
<bullet> The 2025 edition of the Agreement concerning the
International Carriage of Dangerous Goods by Road (ADR 2025), in
paragraph (dd)(4), to replace the 2021 edition of the ADR (ADR 2021),
which is referenced in Sec. Sec. 171.8 and 171.23. The ADR outlines
regulations concerning the international carriage of dangerous goods by
road within the European Union (EU) and other countries that are party
to the agreement. The HMR authorizes its use regarding the definition
of a liquid material and transport of pi marked cylinders. This revised
edition contains the amendments adopted in 2024 by the Working Party on
the Transport of Dangerous Goods. ADR 2025 is available online at:
<a href="https://unece.org/adr-2025-files">https://unece.org/adr-2025-files</a>.
Section 171.8
Section 171.8 defines terms used throughout the HMR. PHMSA proposes
to add a new definition, as adopted in the 23rd revised edition of the
UN Model regulations, to this section for ``sodium ion cell or
battery'' similar to lithium ion cell or battery. PHMSA expects that
adding this definition will provide clarity and enhance safety,
primarily by specifying which sodium ion battery types will be subject
to the newly proposed provisions in this NPRM applicable to sodium ion
batteries.
Section 171.23
Section 171.23 provides conditions and requirements for shipments
of certain packages or materials offered for transportation or
transported in the United States under the ICAO Technical Instructions,
the IMDG Code, the Transport Canada TDG Regulations, or the
International Atomic Energy Agency (IAEA) Regulations--as applicable.
PHMSA proposes to amend paragraph (b)(5), which specifies conditions
and requirements for certain materials, by adding conditions and
requirements for fire suppressant dispersing devices. This amendment
would be consistent with proposed changes that add new HMT entries
``UN0514, Fire suppressant dispersing devices, 1.4S'' and ``UN3559,
Fire suppressant dispersing devices, 9,'' which add a new
classification and packaging section and revise the explosives
packaging section. Detailed summaries of these proposed changes are
found in the discussions of Sections 172.101, 173.62, and 173.169 of
the Section-by-Section Review.
Specifically, for this section, PHMSA proposes that prior to being
transported under authorized international standards and regulations,
the Associate Administrator must approve fire suppressant dispersing
devices in accordance with Sec. Sec. 173.56 and (new) 173.169 of the
HMR. PHMSA also proposes to reorganize paragraph (b) so that the
subject of each provision appears in alphabetical order. This proposed
change is necessary to maintain oversight through the explosives
approval process, which will allow PHMSA to ensure safe transportation
under the new HMT entries and in accordance with the classification,
packaging, and conditional exceptions from movement of these devices
domestically and globally. Devices approved in accordance with an
international competent authority may rely on that documentation for
processing an explosives approval application in the United States.
Part 172
Section 172.101 Hazardous Materials Table (HMT)
The HMT summarizes terms and conditions governing the
transportation of listed hazardous materials under the HMR. For each
entry, the HMT identifies basic information such as the PSN, UN
identification number, and hazard class and hazard label. The HMT
specifies additional information or reference requirements in the HMR,
such as hazard communication, assigned special provisions, packaging
reference citations, and modal requirements, like quantity limits
aboard aircraft, and vessel stowage restriction of hazardous materials
aboard vessels. PHMSA proposes several changes to the HMT as discussed
below. For purposes of the Government Publishing Office's typesetting
procedures, proposed changes to the HMT appear under three sections of
the HMT: ``remove,'' ``add,'' and ``revise.'' Certain entries in the
HMT, such as those with revisions to the PSNs, appear as a ``remove''
and ``add.'' Proposed amendments to the HMT include the following:
New HMT Entries and Revisions to the Appendix B to Sec. 172.101--List
of Marine Pollutants
Fire Suppressant Dispersing Devices (UN0514 and UN3559)
PHMSA proposes to add two new entries to the HMT for fire
suppressant dispersing devices to identify better these articles for
purposes of classification, packaging, and handling for transportation.
See the Section-by-Section discussion of Section 173.169 for a detailed
discussion of fire suppressant dispersing devices and proposed
requirements for their classification, handling, and transportation.
The proposed new entries are ``UN0514, Fire suppressant dispersing
devices, 1.4S'' and ``UN3559, Fire suppressant dispersing devices, 9.''
Fire suppressant dispersing devices are articles containing a
pyrotechnic substance that disperse a fire extinguishing agent (or
generate an aerosol) when activated, and do not contain any other
hazardous materials. To address the prevalence of these articles, the
UNSCOE created two new UN ID numbers and added entries to the
[[Page 6004]]
Dangerous Goods List (DGL) in the 23rd revised edition of the UN Model
Regulations. PHMSA agrees that the addition of these two new entries to
the HMT will provide a description that is more appropriate than
``UN3268, Safety devices, electrically initiated,'' and expects that
the accompanying classification, packaging, and handling provisions
will provide more consistency and for a safe method of transporting
these articles.
Tetramethylammonium Hydroxide (UN1835, UN3423, UN3560)
PHMSA proposes several changes pertaining to tetramethylammonium
hydroxide (TMAH) to align with the 23rd revised edition UN Model
Regulations. TMAH is a quaternary ammonium compound used in the
chemical industry in its solid form and as an aqueous solution. TMAH
solutions are currently transported under ``UN1835, Tetramethylammonium
hydroxide solution,'' as PG II or PG III, with TMAH solids being
transported under ``UN3423, Tetramethylammonium hydroxide, solid,'' as
a PG II. These materials are all classified as Class 8 (corrosive)
material and assigned either PG II or PG III using the criteria in
Sec. 173.137 of the HMR. However, literature studies of incidents
involving accidental human exposure shows that TMAH presents a toxicity
hazard in addition to the currently identified corrosivity hazard.\10\
The studies indicate that TMAH can cause systemic neurotoxic effects
leading to respiratory failure and cardiac arrest in addition to
chemical burns in the event of bodily exposure. The studies showed that
fatalities occurred from exposure to 25 percent TMAH solution.
Furthermore, acute dermal toxicity studies indicated increasing toxic
properties as concentration of TMAH solutions increased. Consequently,
the UNSCOE determined that there was a need for a revised
classification for TMAH materials to account for toxic properties.
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\10\ United Nations Economic Commission for Europe (UNECE),
Additional data on proposal ST/SG/AC.10/C.3/2022/24--Revision of
classification of tetramethylammonium hydroxide (June 16, 2022),
available at: <a href="https://unece.org/sites/default/files/2022-06/UN-SCETDG-60-INF22.e_0.pdf">https://unece.org/sites/default/files/2022-06/UN-SCETDG-60-INF22.e_0.pdf</a>.
---------------------------------------------------------------------------
The proposed amendments include the addition of a new entry
describing a TMAH aqueous solution of at least 25 percent TMAH--
``UN3560, Tetramethylammonium hydroxide aqueous solution with not less
than 25 percent tetramethylammonium hydroxide'' in the HMT. This new
entry would have a primary hazard of Division 6.1 (toxic), a subsidiary
hazard of Class 8 (corrosive), and be assigned to PG I. Consistent with
this new table entry for 25 percent TMAH aqueous solutions, additional
changes are proposed for existing TMAH HMT entries to further account
for the toxicity hazard and clarify their use, including revisions to
the proper shipping names and descriptions, the hazard classification
of PG II TMAH solutions (UN1835) reclassification of TMAH solids
(UN3423) and revised packaging authorizations, and the assignment of
two new special provisions (i.e., 408 and 409).
PHMSA proposes revisions to the TMAH solution (UN1835) shipping
description to aid shippers with selecting the most appropriate
hazardous materials description and to delineate clearly the
classification and PG assignment. For the PSN ``Tetramethylammonium
hydroxide solution,'' the term ``aqueous'' is added to clarify that the
PSN applies to aqueous solutions of TMAH. See the Section-by-Section
Review discussion of Section 172.102, Special Provision 408, for
further context. Furthermore, concentration ranges corresponding to the
assigned PG are added in italics to be used in addition to the PSN.
Specifically, the revised hazardous materials description for the PG II
entry would read ``Tetramethylammonium hydroxide aqueous solution with
more than 2.5 percent but less than 25 percent tetramethylammonium
hydroxide,'' and the PG III entry would read ``Tetramethylammonium
hydroxide aqueous solution with not more than 2.5 percent
tetramethylammonium hydroxide.''
With respect to the revised classification for TMAH solution
(UN1835), PHMSA proposes to add a Division 6.1 subsidiary hazard for
the PG II entry--i.e., TMAH aqueous solutions containing more than 2.5
percent but less than 25 percent TMAH. This amendment addresses the
data from human exposure incidents and toxicity studies that
demonstrated an increasing toxicity property for TMAH solutions as
concentration increased.
Similarly, for TMAH, solid (UN3423), which is currently classified
as Class 8, PG II, the UNSCOE reclassified as a primary hazard of
Division 6.1, a subsidiary hazard of Class 8, and assigned PG I. PHMSA
agrees with this reclassification based on human experience and acute
toxicity studies. PHMSA concurs with this determination due to the
reclassification of the material to a PG I material. Therefore, PHMSA
proposes to change the primary hazard from Class 8 to Division 6.1 in
column (3) of the HMT and transition the Class 8 corrosivity hazard to
a subsidiary hazard as designated in column (6) of the HMT. In
addition, with this hazard reclassification, the PG for UN3423 would be
changed from PG II to PG I. PHMSA also notes that in the latest
revisions to the DGL in the UN Model Regulations, the limited quantity
exception authorization for this entry was removed.
Lastly, PHMSA proposes to assign two new special provisions--
Special Provisions 408 and SP 409--to these entries. Special Provision
408 would provide additional hazard communication instructions for
certain mixtures containing TMAH and would be assigned to all three
TMAH solution entries, stating that the use of those proper shipping
names is limited to aqueous solutions comprised of water,
tetramethylammonium hydroxide, and no more than one (1) percent of
other constituents. This new special provision would also provide
instruction that other formulations containing more than one percent
surfactants and certain concentration ranges of TMAH (>=8.75 percent
or, >2.38 to <8.75 percent, respectively) must be described using ``UN
2927, Toxic liquid, corrosive, organic, n.o.s.,'' while other
formulations not meeting the criteria in the SP 408 must be assigned to
an alternative appropriate generic or n.o.s. HMT entry.\11\ PHMSA
expects that providing instruction on the appropriate use of TMAH
aqueous solution descriptions and generic or n.o.s. HMT entries for
formulations other than aqueous solutions that contain TMAH would make
things clearer for shippers of TMAH mixtures with regard to appropriate
hazard communication and associated packaging requirements. PHMSA also
proposes to assign new Special Provision 409 to all three TMAH solution
entries and the TMAH solid entry to allow shipment using the current
hazard communication through December 31, 2026, to allow time for
offerors to adjust their hazard communication (see the Section-by-
Section Review in Section 172.102 for additional information). PHMSA
expects these hazard classification and communication changes will
enhance safety by providing more appropriate packaging and transport
requirements and more accurate hazard information for handlers of TMAH
packages and emergency responders.
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\11\ For clarity, n.o.s. means not otherwise specified (in the
HMT).
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[[Page 6005]]
Sodium Ion Batteries With Organic Electrolyte and Sodium Ion Batteries
Contained in Equipment With Organic Electrolyte/Sodium Ion Batteries
Packed With Equipment, With Organic Electrolyte (UN3551 and UN3552)
PHMSA proposes to add three new entries for sodium ion batteries to
the HMT: ``UN3551, Sodium ion batteries with organic electrolyte,''
``UN3552, Sodium ion batteries contained in equipment, with organic
electrolyte,'' and ``UN3552, Sodium ion batteries packed with
equipment, with organic electrolyte.'' These all describe materials of
Class 9. The UN Model Regulations have recently adopted provisions
regulating sodium ion cells and batteries in much the same way as
lithium ion cells and batteries. Sodium ion technology has the
potential to be a low-cost alternative to lithium ion batteries in
certain applications. Both sodium ion batteries and lithium ion
batteries are rechargeable energy storage devices, with sodium ion
batteries using sodium ions to carry a charge and lithium ion batteries
using lithium ions to carry a charge. Both present similar hazards due
to their energy density. A key operational difference between sodium
ion and lithium ion technology is that sodium ion technology can be
discharged to zero volts (i.e., a zero state-of-charge) without
affecting the performance of the battery. Batteries using sodium ion
technology can therefore be stored and transported in a completely
discharged state, with terminals shorted if required, greatly reducing
their hazard. However, PHMSA and the UNSCOE agree that the same
requirements that apply to lithium ion batteries are appropriate for
sodium ion batteries given that the two demonstrate similar risks.
Like previous versions of the UN Model Regulations, the HMR does
not currently have a hazardous material description for sodium ion
batteries. The current entry in the HMT of ``Batteries, containing
sodium'' (UN3292) is applicable to various cell chemistries, such as
sodium sulfur and sodium metal chloride which contain metallic sodium,
but does not specifically address batteries of sodium ion cell
chemistry. When evaluating the proposed adoption of requirements for
sodium ion batteries, the UNSCOE analyzed the quantity and nature of
gases emitted during the thermal runaway of sodium ion batteries from
tests conducted at the French National Institute for Industrial
Environment and Risks.\12\ Results showed similarities between the
quantity and nature of the gases emitted during the thermal runaway of
sodium ion batteries and during the thermal runaway of certain types of
lithium ion battery chemistries.
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\12\ UNECE, Sodium ion batteries: Assignment of a dedicated UN
number and related special provisions--Follow-up on document ST/SG/
AC.10/C.3/2020/45/Rev.1 (Sept. 20, 2021), available at: <a href="https://unece.org/sites/default/files/2021-09/ST-SG-AC.10-C.3-2021-55e.pdf">https://unece.org/sites/default/files/2021-09/ST-SG-AC.10-C.3-2021-55e.pdf</a>.
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With the results of these tests, along with information indicating
that by 2023 companies were planning to mass produce sodium ion
batteries to alleviate supply chain issues with lithium ion batteries,
the UNSCOE adopted provisions to regulate sodium ion batteries in the
same manner as lithium ion batteries. PHMSA now aims to harmonize with
current international regulations by adopting those same provisions.
PHMSA expects that as sodium ion batteries become more widely used,
harmonizing the HMR with international standards will provide a
baseline of uniform transport standards. For sodium ion batteries being
transported domestically or exported by U.S. companies abroad, this
standardization will ultimately allow for reduced burdens, increased
efficiency, and avoid unnecessary costs for domestic industries--
leading to less expensive product options for domestic consumers. See
the Section-By-Section Review in Section 173.185 for further detail of
the proposed classification, packaging provisions, and exceptions for
sodium ion batteries.
In addition, PHMSA proposes to assign a new special provision for
sodium ion batteries, and to make many of the existing special
provisions related to lithium ion batteries applicable to sodium ion
batteries. See the Section-By-Section Review in Section 172.102 for
further details of proposed special provisions applicable to sodium ion
batteries.
Lastly, PHMSA proposes to make one of the vessel stowage codes that
is currently assigned to lithium ion batteries applicable to sodium ion
batteries, including sodium ion batteries packed with, or contained in,
equipment. PHMSA expects this change will enhance safety by ensuring
sodium ion batteries are properly stowed when transported by vessel.
See the Section-By-Section Review in Section 172.101, column (10)
discussion of for additional details on this amendment.
Disilane (UN3553)
PHMSA proposes to add a new entry, ``UN3553, Disilane, 2.1,'' to
the HMT. Disilane is a pyrophoric liquified gas under pressure that is
spontaneously flammable in air and does not require spark or flame to
ignite. Disilane is used primarily in the manufacture of integrated
circuits in various electronics, including computer processors. Despite
its pyrophoric properties, disilane is commonly transported under the
generic shipping description, ``UN3161, Liquefied gas, flammable,
n.o.s. (Disilane).'' As a part of their review of proposed amendments
to the UN Model Regulations, the UNSCOE discussed the need for a more
specific proper shipping name that would better reflect the flammable
and pyrophoric properties of disilane. The UNSCOE concluded that the
use of the generic description for disilane only reflects its
flammability properties but not the pyrophoric properties. Unlike
``UN2203, Silane'' and other similar pyrophoric materials that are
forbidden for transport by cargo aircraft, disilane, as currently
transported under ``UN3161, Liquefied gas, flammable, n.o.s.
(Disilane),'' is not forbidden for transport by cargo aircraft.\13\ The
UNSCOE concluded that a separate shipping description for disilane
should be created to clarify the pyrophoric properties of the material
and ensure that there is no possibility of disilane being transported
by air.
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\13\ Both UN2203 and UN3161 are forbidden for transport aboard
passenger aircraft.
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Consistent with the ICAO Technical Instructions for disilane, PHMSA
proposes to add the entry to the HMT, noting that ``Forbidden'' would
be indicated in column (9) for both passenger and cargo aircraft. For
shipments by vessel, PHMSA proposes to assign stowage code D, which
requires that the material is stowed on deck when transported on a
cargo vessel and further limits the stowage of the material by vessel
when passengers are present. In addition, PHMSA proposes to assign
segregation codes, 40, 57, and 104 in column (10B) to require that
disilane be segregated from living quarters, from chlorine, and from
bromine to prevent hazardous reactions. These stowage and segregation
provisions are consistent with the requirements adopted in Amendment
42-24 to the IMDG Code. PHMSA expects that adding this new entry and
the new packaging provisions will enhance safety by providing a clearer
hazard identification of disilane and ensuring that there is no
possibility of this product being transported by air.
[[Page 6006]]
Gallium Contained in Manufactured Articles (UN3554)
PHMSA proposes to add ``UN3554, Gallium contained in manufactured
articles,'' as a new entry to the HMT. Gallium is a silver white metal
with a low melting point and, though corrosive to certain metals like
aluminum, is widely considered a safer, non-toxic alternative to
mercury. Gallium and its alloys are used in a variety of products in
place of mercury products--such as thermometers and UV lamps. This
transition away from mercury has been driven largely in response to the
2013 Minamata Convention on Mercury (i.e., Convention).\14\ The
Convention aimed to reduce mercury emissions and exposure, through the
reduced production, import, and export of mercury-containing products.
Since 2017, manufacturers have explored substitutes to mercury-
containing products.\15\ To facilitate the use of this alternative
material, PHMSA proposes new packaging provisions for this new entry to
mirror the provisions for ``UN3506, Mercury contained in manufactured
articles''--which have been authorized in the HMR since 2013 and have a
well demonstrated safety record.\16\ See the Section-by-Section Review
in Section 173.162 for additional information on the new packaging
provisions for this entry. PHMSA expects that this new entry will
provide consistency with international regulations and allow for a less
toxic material to be integrated into the market.
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\14\ United Nations, 2013 Minamata Convention on Mercury (Oct.
10, 2013), available at: <a href="https://treaties.un.org/doc/Treaties/2013/10/20131010%2011-16%20AM/CTC-XXVII-17.pdf">https://treaties.un.org/doc/Treaties/2013/10/20131010%2011-16%20AM/CTC-XXVII-17.pdf</a>.
\15\ UNECE, Proposal to amend SP 366, making it also adjust to
Gallium contained in manufactured articles (Apr. 16, 2021),
available at: <a href="https://unece.org/sites/default/files/2021-04/ST-SG-AC.10-C.3-2021-17e.pdf">https://unece.org/sites/default/files/2021-04/ST-SG-AC.10-C.3-2021-17e.pdf</a>.
\16\ 78 FR 988 (Jan. 7, 2013).
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Trifluoromethyltetrazole-Sodium Salt (UN3555)
PHMSA proposes to add a new entry, ``UN3555,
Trifluoromethyltetrazole-sodium salt in acetone, with not less than 68%
acetone, by mass, 3, PG II,'' to the HMT. PHMSA proposes to add a new
entry, ``UN3555, Trifluoromethyltetrazole-sodium salt in acetone, with
not less than 68% acetone, by mass, 3, PG II,'' to the HMT.
Trifluoromethyltetrazole, sodium salt (TFMT-Na) in acetone is a
desensitized explosive compound used as a precursor material for a new
insecticide that is entering the market. Due to the explosive
properties of the dry substance, it is only handled and transported as
a homogenous solution in acetone. As a result of its unique properties,
the UNSCOE agreed to create a new entry on the DGL to facilitate its
transport as its use is expected to increase across various countries.
PHMSA proposes to mirror the UN Model Regulations' corresponding
packaging provisions for this hazardous material by creating a new
special provision, Special Provision 234. This new special provision
will specify the authorized packaging for this material. In addition,
PHMSA is assigning Special Provision 74 which would require that:
1. The material be protected from direct sunlight; and
2. The material be stored or kept in a cool and well-ventilated
place away from all sources of heat.
PHMSA is also assigning Special Provision 162 to permit the
material be transported under the provisions of Class 3, provided it is
packed so that the percentage of diluent will not fall below the stated
amount at any time during transport. PHMSA notes that the entry
includes ``Forbidden'' in column (9) for both passenger and cargo
aircraft, which is consistent with the ICAO Technical Instructions.
PHMSA expects that the addition of this new HMT entry and associated
authorized packaging requirements will facilitate the safe transport of
this emerging product domestically and internationally.
Lithium Ion Battery Powered Vehicle, Lithium Metal Battery Powered
Vehicle, and Sodium Ion Battery Powered Vehicle (UN3556, UN3557, and
UN3558, Respectively)
PHMSA proposes to add three new entries to the HMT for vehicles
powered by lithium ion batteries, lithium metal batteries, and sodium
ion batteries to address the massive market growth in personal mobility
devices, such as e-bikes, e-scooters, e-skateboards, and other
lightweight vehicles. The proposed new entries are: ``UN3556, Vehicle,
lithium ion battery powered,'' ``UN3557, Vehicle, lithium metal battery
powered,'' and ``UN3558, Vehicle, sodium ion battery powered.'' These
entries will provide more precise descriptions for vehicles powered by
various battery chemistries (e.g., lithium or sodium ion cells or
lithium metal cells), rather than relying on the broadly used entry
``UN3171, Battery-powered vehicle.'' Currently, there are two distinct
entries that cover products containing lithium ion and lithium metal
cells and batteries (UN3480 and UN3090); however, the same
differentiation does not exist for vehicles powered by various battery
types. The UNSCOE addressed this lack of distinction, clarity, and
consistency by adding these three new UN numbers and proper shipping
names to the DGL in the UN Model Regulations. PHMSA agrees with the
UNSCOE's solution and expects that the addition of these specific
hazardous materials descriptions will provide a differentiation between
vehicles powered by lithium batteries, sodium ion batteries and other
battery powered vehicles and help to identify better the batteries in
these vehicles for emergency response purposes. PHMSA does not expect
that this amendment will impose additional costs as the packaging
provisions are the same for each vehicle type. For example, non-
spillable battery powered vehicles should continue to use the entry
``UN3171, Battery-powered vehicle.'' PHMSA expects that the addition of
these new entries will facilitate the efficient transport of these
hazardous materials by providing better shipping descriptions and more
precise hazard communication.
Additions to Appendix B to Sec. 172.101--List of Marine Pollutants
Appendix B to Sec. 172.101--List of Marine Pollutants lists
potential marine pollutants as defined in Sec. 171.8 of the HMR. To
align with Amendment 42-24 to the IMDG Code, PHMSA proposes to add
isopropenylbenzene, 2-phenylpropene, and cobalt dihydroxide powder,
containing more than 10 percent respirable particles to this list.
Isopropenylbenzene is currently listed by name in the HMT under UN2303
and has the same chemical structure as 2-phenylpropene, which makes the
two names synonymous. Following additional testing--which was required
for compliance with the Registration, Evaluation, Authorization and
Restriction of Chemicals (REACH) regulations in the EU--the IMO agreed
to add these entries to the list of marine pollutants in Amendment 42-
24 of the IMDG Code. The testing results showed that the substance
meets the criteria to be classified as an ``Environmentally hazardous
substance (aquatic environment)'' as stipulated in section 2.9.3 of the
IMDG Code.
With respect to the addition of cobalt dihydroxide powder
containing more than 10 percent respirable particles to the marine
pollutants list, in a previous rulemaking--HM-215Q--PHMSA added this
material to the HMT as ``UN3550, Cobalt dihydroxide powder containing
more than 10 percent respirable particles.'' \17\ PHMSA made that
addition to harmonize with changes made to the Amendment 41-22 to the
[[Page 6007]]
IMDG Code and 2023-2024 edition to the ICAO Technical Instructions, and
the 22nd revised edition of the UN Model Regulations, after testing
required under REACH regulations determined that this material poses an
inhalation toxicity hazard. This material was also added to the list of
the marine pollutants in Amendment 41-22 of the IMDG Code; however,
PHMSA inadvertently omitted this material as an entry on the list of
marine pollutants under the HM-215Q rulemaking. Like
isopropenylbenzene/2-phenylpropene, PHMSA added cobalt dihydroxide
powder, containing more than 10 percent respirable particles because
that material also meets the criteria under the IMDG Code to be
classified as ``Environmentally hazardous substance (aquatic
environment).'' PHMSA proposes to correct this unintentional oversight
and add ``Cobalt dihydroxide powder containing more than 10 percent
respirable particles'' to the list of marine pollutants. PHMSA expects
that these amendments will help improve safety to the aquatic
environment for the transport of these materials and that the
harmonization of the list of marine pollutants will facilitate
appropriate transport of these materials.
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\17\ 89 FR 25434 (Apr. 10, 2024).
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Revisions to the HMT Columns of Information
Column (1) Symbols
Section 172.101(b) describes column (1), which may contain one of
six symbols: ``+'', ``A'', ``D'', ``G'', ``I'' and ``W''. The plus (+)
sign fixes the proper shipping name, hazard class, and packing group
for that entry without regard to whether the material meets the
definition of that class, packing group, or any other hazard class
definition. When the plus sign is assigned to a proper shipping name in
column (1) of the HMT, it means that the material is known to pose a
risk to humans.
PHMSA proposes to add a (+) in column (1) of the HMT for the
following entries: ``UN1835, Tetramethylammonium hydroxide aqueous
solution with more than 2.5 percent but less than 25%
tetramethylammonium hydroxide'', ``UN3423, Tetramethylammonium
hydroxide, solid,'' and ``UN3560, Tetramethylammonium hydroxide aqueous
solution with not less than 25% tetramethylammonium hydroxide.'' As
discussed below, PHMSA proposes to amend the hazard classification for
these entries based on additional data regarding their toxicity (see
additional discussion of TMAH amendments throughout the Section-by-
Section discussion 172.101). The additions in column (1) would reflect
the basis for these classification changes.
In addition, this proposed amendment would align with the changes
adopted in the 23rd revised edition of the UN Model Regulations, which
assigned Special Provision 279 to these entries. Special Provision 279,
like the (+) in column (1), fixes the assigned classification or
packing group based on human experience rather than the strict
application of classification criteria. PHMSA expects this change will
enhance safety by ensuring that these materials are properly classified
and packaged to address the newly identified toxicity hazard.
Column (2) Hazardous Materials Descriptions and Proper Shipping Names
Section 172.101(c) describes column (2) of the HMT and the
requirements for hazardous materials descriptions and PSNs. PHMSA
proposes to revise the hazardous material description for ``UN1835,
Tetramethylammonium hydroxide solution, 8, PG II and III.'' For the PG
II entry, PHMSA proposes to add the word ``aqueous'' as part of the PSN
and include a concentration range in italics to read ``aqueous solution
with more than 2.5 percent but less than 25 percent tetramethylammonium
hydroxide.'' For the PG III entry, PHMSA proposes to add the word
``aqueous'' as part of the PSN and include a concentration range to
read ``aqueous solution with not more than 2.5 percent
tetramethylammonium hydroxide.'' These proposals align with the
proposed changes to the classification of TMAH material as discussed
above. PHMSA expects that they will provide an additional level of
safety for transportation of aqueous solutions of TMAH by more
accurately describing the material.
PHMSA also proposes to modify the proper shipping name of ``UN1010,
Butadienes and hydrocarbon mixture, stabilized containing more than 40%
butadienes,'' by revising the concentration range in italics from
``containing more than 40% butadienes'' to ``containing more than 20%
butadienes.'' PHMSA modified this hazardous material description in a
prior rulemaking, HM-215G, by adding the italicized text that
stipulated the 40 percent concentration of butadienes to describe
better certain mixtures.\18\ This change was intended to facilitate the
classification and transport of mixtures of liquefied petroleum gases,
which were already being classified under UN1010 in other countries.
However, after evaluating typical shipments of butadiene/hydrocarbon-
mixtures, the European Chemical Industry Council (Cefic) determined
that most fall within the 20 to 40 percent butadiene concentration
range. As a result, the current butadiene concentration requirement of
40 percent or more associated with the use of UN1010 means that less
accurate PSNs, such as ``UN1965, Hydrocarbon gas mixture, liquefied,
n.o.s.,'' or ``UN3161, Liquefied gas, flammable, n.o.s.,'' are used for
many shipments of this material (i.e., shipments with concentrations of
butadienes below 40 percent). The UNSCOE reasoned that it was
preferable to lower the concentration threshold to facilitate the use
of the proper shipping description for a wider group of shipments,
given that this PSN clearly reflects the specific danger of butadiene
(e.g., carcinogenic), as opposed to using a generic ``n.o.s.'' entry,
such as ``UN3161, Liquefied gas, flammable, n.o.s.'' This change would
provide emergency responders with immediate information regarding the
material being transported and removes the need to seek out the
shipping paper to determine that butadiene is involved in an incident.
PHMSA agrees with this determination and expects that adjusting the
concentration range associated with this PSN will improve safety by
providing first responders with better information for effectively
responding to incidents involving butadiene mixtures, as well as
providing important carcinogenicity risk information for handlers of
these mixtures.
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\18\ 69 FR 76044 (Dec. 20, 2004).
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For the entries ``UN3292, Batteries, containing sodium'' and
``UN3292, Cells containing sodium,'' PHMSA proposes to revise the PSNs
to ``Batteries, containing metallic sodium or sodium alloy,'' and
``Cells, containing metallic sodium or sodium alloy,'' respectively.
This change will harmonize the entries with the UN Model Regulations,
which revised the UN3292 entry to provide a clear distinction between
sodium metal batteries and the new HMT entries for sodium ion
batteries. PHMSA expects this proposal will improve safety by providing
additional clarity to ensure shipments of batteries, specifically
sodium metal batteries and sodium ion batteries, are properly
classified, packaged, and transported.
[[Page 6008]]
Column (3) Hazard Class or Division
Section 172.101(d) describes column (3) of the HMT, which
designates the hazard class or division corresponding to the PSN of
that entry. As part of the changes for TMAH discussed above, PHMSA
proposes to change the primary hazard class of ``UN3423,
Tetramethylammonium hydroxide, solid'' to align with the with changes
adopted in the 23rd revised edition of the UN Model Regulations.
Currently, UN3423 is a Class 8 corrosive material, but both human
exposure and toxicity studies have demonstrated that solid TMAH has a
significant toxicity hazard as well. UN3423 demonstrates a toxicity
hazard and meets the criteria for Class 8 and Division 6.1 hazards. In
accordance with Sec. 173.2a, a Division 6.1 hazard should be the
primary hazard class as it has precedence over a Class 8 hazard when
classifying a material with multiple hazards. For that reason, PHMSA
proposes to replace ``8'' in column (3) with ``6.1'' and add Class 8 as
a subsidiary hazard to column (6). PHMSA expects this proposed action
will improve safety by more accurately communicating the primary hazard
of the material and providing uniform hazard communication for
international shipments.
Column (5) Packing Group
Section 172.101(f) describes column (5) of the HMT, which specifies
one or more packing groups (PG I, II, or III) assigned to certain
materials. A PG indicates the required level of packaging according to
the degree of danger presented by hazardous materials.
PHMSA proposes to remove the PG assigned to two HMT entries:
``UN2028, Bombs, smoke, non-explosive, with corrosive liquid, without
initiating device'' and ``UN3165, Aircraft hydraulic unit fuel tank
(containing a mixture of anhydrous hydrazine and monomethyl hydrazine)
(M86 fuel).'' PHMSA proposes to adopt these changes for consistency
with the HMR, which does not assign PGs to articles in classes other
than Class 1 in the HMT, and to align with the conventions adopted in
the UN Model Regulations in 2012, which also removed PGs assigned to
all articles in the DGL. PHMSA expects that removing this inconsistency
will maintain the current level of safety for transport of these
materials.
In addition, as a part of various changes discussed above
pertaining to the hazard classification of TMAH, PHMSA proposes to
change the PG of ``UN3423, Tetramethylammonium hydroxide, solid'' from
PG II to PG I. This change in assignment from PG II to PG I is based on
human experience and toxicity data that indicates a PG I toxicity
hazard for TMAH solids is appropriate. PHMSA expects that this change
will enhance safety by requiring a higher standard for packaging for
this material.
Column (6) Label Codes
Section 172.101(g) describes column (6) of the HMT, which contains
label codes representing the hazard warning labels required for a
package filled with a material conforming to the associated hazard
class and proper shipping name, unless the package is otherwise
excepted from labeling. The first code is indicative of the primary
hazard of the material. Additional label codes are indicative of
subsidiary hazards.
For ``UN3423, Tetramethylammonium hydroxide, solid,'' which is
currently classified as a Class 8 corrosive material, PHMSA proposes to
revise the label code to indicate a primary Division 6.1 and subsidiary
Class 8 hazard. For ``UN3560, Tetramethylammonium hydroxide aqueous
solution with not less than 25% tetramethylammonium hydroxide,'' PHMSA
proposes to add a 6.1 and 8 label code to correspond to this entry's
primary and subsidiary hazards. For ``UN1835, TMAH aqueous solutions
with more than 2.5% but less than 25% TMAH, PGII,'' PHMSA proposes to
add a subsidiary Division 6.1 hazard, which would also be reflected in
column (6). Accidental human exposure and acute dermal toxicity studies
demonstrates the toxic properties of TMAH, which is discussed in
greater detail above in the summary of amendments associated with the
new TMAH solution HMT entry (i.e., UN3560). PHMSA expects these changes
will increase safety by more appropriately communicating the hazards of
these materials.
Column (7) Special Provisions
Section 172.101(h) describes column (7) of the HMT, which assigns
special provisions for each HMT entry. Section 172.102 provides for the
meaning and requirements of the special provisions assigned to entries
in the HMT. The proposed revisions to column (7) of certain entries in
the HMT are discussed below.
For ``UN1006, Argon,'' ``UN1013, Carbon dioxide,'' ``UN1046,
Helium,'' and ``UN1066, Nitrogen,'' PHMSA proposes to assign a new
Special Provision 406, which would allow these materials to be
transported in DOT specification cylinders and UN pressure receptacles
as a limited quantity material in quantities not more than 1000 ml (34
fluid ounces) per package. For additional details on this new
provision, see the Section-by-Section Review in Section 172.102.
For ``UN1010, Butadienes and hydrocarbon mixture, stabilized
containing more than 20% butadienes,'' PHMSA proposes to assign new
Special Provision 402, which would specify required conditions for
transport under this entry. For additional information on this new
special provision, see the Section-by-Section Review in Section
172.102.
For ``UN1391, Alkali metal dispersions or Alkaline earth metal
dispersions,'' and ``UN3482, Alkali metal dispersions, flammable or
Alkaline earth metal dispersions, flammable,'' PHMSA proposes to assign
six special provisions, i.e., Special Provisions 64, 65, T13, TP2, TP7,
and a newly proposed Special Provision, TP42. These special provisions
would provide clear direction as to which alkali metals and alkaline
earth metals are included under these PSNs and would provide packaging
flexibility by authorizing the transport of these materials, which are
slurries comprised of metal powders and a hydrocarbon solvent, in
portable tanks rather than limiting these materials to other bulk and
non-bulk packaging provisions in Sec. Sec. 173.201 and 173.244. These
additional portable tank packaging provisions were adopted in the 23rd
revised edition of the UN Model Regulations to facilitate the transport
of alkali metals that are incorporated in liquid dispersions for the
manufacture of items such as lithium battery anodes. As the global
demand for lithium increases, particularly given the potential use in
energy storage applications, the need has arisen for the international
transport of alkali metal and alkaline earth metal dispersions in
portable tanks. Prior to changes adopted in the UN Model Regulations,
the DGL did not indicate any portable tank instructions for these
materials. Consequently, these hazardous materials were not permitted
to be transported in UN portable tanks unless a competent authority
approval was granted. The newly assigned T and TP code packaging
provisions were adopted for consistency with the Guiding Principles for
the Development of the UN Model Regulations, which indicates that
liquid Division 4.3 substances of PG I are--in principle--considered
suitable for transport in portable tanks conforming to portable tank
instructions.\19\ To facilitate the transport
[[Page 6009]]
of these materials, PHMSA proposes to amend the associated packaging
provisions to authorize the transport of alkali metal dispersions and
alkaline earth metal dispersions in portable tanks that conform to tank
instructions in Special Provisions T13, which requires a higher minimum
test pressure of 6 bar, a minimum shell thickness of 6 mm, and
prohibits bottom outlets; TP2, which provides a specific formula for
the maximum degree of filling; and TP7, which requires that the vapor
space has to be purged of air by nitrogen or other means. In addition,
PHMSA proposes to assign a new Special Provision TP42 to add
supplemental provisions for the transport of alkali metal dispersions
that are considered highly reactive. PHMSA expects that by expanding
the packaging options, these amendments will facilitate access to
affordable, reliable, sustainable, and modern energy sources and offer
greater flexibility in the packaging that may be used to transport
these materials. For additional details on these TP codes, see the
Section-by-Section Review in Section 172.102.
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\19\ This document outlines the underlying principles that have
been applied in developing the UN Model Regulations and outlines the
approach taken during the development of its provisions.
---------------------------------------------------------------------------
For ``UN1835, Tetramethylammonium hydroxide aqueous solution with
more than 2.5 percent but less than 25 percent tetramethylammonium
hydroxide, PGII,'' ``UN1835, Tetramethylammonium hydroxide aqueous
solution with not more than 2.5 percent tetramethylammonium hydroxide,
PGIII,'' ``UN3560, Tetramethylammonium hydroxide aqueous solution with
not less than 25 percent tetramethylammonium hydroxide,'' and ``UN3423,
Tetramethylammonium hydroxide, solid,'' PHMSA proposes to assign two
new special provisions--408 and 409. Special Provision 408 would be
assigned to UN1835 (PG II and PG III) and UN3560, and Special Provision
409 would be assigned to UN1835 (PG II and PG III), UN3560, and UN3423.
Special provision 408 will provide instruction on appropriate hazardous
materials descriptions for aqueous solutions of TMAH with differing
formulations and constituents, while Special Provision 409 will provide
a delayed compliance date for use of the new HMT entries and revised
hazard information to allow industry time to adjust their hazard
communication and associated packaging and handling provisions. See the
Section-by-Section Review in Section 172.102 for additional discussion
of these new special provisions. PHMSA expects that these proposed
changes will facilitate the safe transport of these materials by
clearly outlining the hazardous communications requirements.
For ``UN2795, Batteries, wet, filled with alkali, electric
storage,'' ``UN3292, Batteries, containing metallic sodium or sodium
alloy,'' and ``UN3292, Cells, containing metallic sodium or sodium
alloy,'' PHMSA proposes to assign new Special Provision 401 to help to
distinguish between shipping descriptions that describe batteries and
cells with sodium as their electrolyte. Special Provision 401 will also
be assigned to the proposed new entries for sodium ion batteries,
``UN3551, Sodium ion batteries with organic electrolyte,'' ``UN3552,
Sodium ion batteries contained in equipment with organic electrolyte,''
and ``UN3552, Sodium ion batteries packed with equipment, with organic
electrolyte.'' For additional information, see the Section-by-Section
Review in Section 172.102.
For ``UN2803, Gallium,'' PHMSA proposes to assign Special Provision
365, which is also proposed to be amended in this NPRM. See the
Section-by-Section Review in Section 172.102 for further discussion of
amendment to Special Provision 365. Currently, ``UN2803, Gallium'' is
only assigned to Special Provisions T1 and TP33, which provide
requirements for portable tanks. Special Provision 365 would provide
instructions on the use of ``UN2803, Gallium,'' or the newly added
entry, ``UN3554, Gallium contained in manufactured articles.''
For ``UN3270, Nitrocellulose membrane filters, with not more than
12.6% nitrogen, by dry mass,'' PHMSA proposes to amend the special
provision that is currently assigned, Special Provision 43. This
special provision would provide an exception from regulation for these
materials that meet the packaging requirements specified in Special
Provision 43. For additional information, see the Section-by-Section
Review in Section 172.102.
``UN3423, Tetramethylammonium hydroxide, solid,'' is currently
assigned several special provisions, including IB8, which provides the
list of authorized intermediate bulk containers (IBCs) for this
material. PHMSA proposes to replace IB8 with IB7. This change is
consistent with the proposed revisions pertaining to the hazard
classification of TMAH solids. Like IB8, IB7 authorizes IBCs made of
metal, rigid plastics, composite materials, and wood. But unlike IB8,
IB7 does not authorize fiberboard or flexible IBCs. PHMSA finds that
removing the authorization for fiberboard and flexible IBCs is an
appropriate change to ensure continued safety for the transport of this
material given the proposed revised hazards presented during
transportation. Consistent with the revised assignment of IB7, PHMSA
also proposes to replace IP2 with IP1. IP2 only requires certain IBCs
to be offered for transportation in a closed freight container or a
closed transport vehicle, whereas IP1 requires the use of closed
freight containers or a closed transport vehicle for all IBC types that
contain UN3423. Assigning IP1 is consistent with assignment of IP1 to
other Division 6.1, PG I materials listed in the HMT. PHMSA proposes to
replace T3 with T6 as well. Replacing T3 with T6 will increase the
safety and performance requirements of these packagings by increasing
the minimum test pressure from 2.65 bar to 4 bar. This change reflects
the same change made in the latest edition of the UN Model Regulations.
PHMSA proposes to assign Special Provision 162 (as proposed to be
amended, see discussion in Section-by-Section Review in Section 172.102
for additional information) to ten additional entries on the HMT.
Currently, Special Provision 162 is only assigned to desensitized
explosives classed as Division 4.1 solids. PHMSA proposes to amend the
text of Special Provision 162 to include desensitized explosives
classified as Class 3 flammable liquids. PHMSA also proposes to assign
Special Provision 162 to some additional Division 4.1 hazardous
materials for which this standard applies but which were not previously
specified. PHMSA proposes to assign Special Provision 162 to the
following Class 3 and Division 4.1 hazardous materials as follows:
<bullet> ``UN1204, Nitroglycerin solution in alcohol with not more
than 1 percent nitroglycerin, 3, PG II''.
<bullet> ``UN2059, Nitrocellulose, solution, flammable with not
more than 12.6 percent nitrogen, by mass, and not more than 55 percent
nitrocellulose, 3, PG I''.
<bullet> ``UN2059, Nitrocellulose, solution, flammable with not
more than 12.6 percent nitrogen, by mass, and not more than 55 percent
nitrocellulose, 3, PG II''.
<bullet> ``UN2059, Nitrocellulose, solution, flammable with not
more than 12.6 percent nitrogen, by mass, and not more than 55 percent
nitrocellulose, 3, PG III''.
<bullet> ``UN2555, Nitrocellulose with water with not less than 25
percent water, by mass, 4.1, PG II''.
<bullet> ``UN2556, Nitrocellulose with alcohol with not less than
25 percent alcohol by mass, and with not more than 12.6 percent
nitrogen, by dry mass, 4.1, PG II''.
<bullet> ``UN2907, Isosorbide dinitrate mixture with not less than
60 percent
[[Page 6010]]
lactose, mannose, starch or calcium hydrogen phosphate, 4.1, PG II''.
<bullet> ``UN3064, Nitroglycerin, solution in alcohol, with more
than 1 percent but not more than 5 percent nitroglycerin, 3, PG II''.
<bullet> ``UN3319, Nitroglycerin mixture, desensitized, solid,
n.o.s. with more than 2 percent but not more than 10 percent
nitroglycerin, by mass, 4.1, PG II''.
<bullet> ``UN3343, Nitroglycerin mixture, desensitized, liquid,
flammable, n.o.s. with not more than 30 percent nitroglycerin, by mass,
3, PG II''.
<bullet> ``UN3344, Pentaerythrite tetranitrate mixture,
desensitized, solid, n.o.s. or Pentaerythritol tetranitrate mixture,
desensitized, solid, n.o.s. or PETN mixture, desensitized, solid,
n.o.s., with more than 10 percent but not more than 20 percent PETN, by
mass, 4.1, PG II''.
<bullet> ``UN3357, Nitroglycerin mixture, desensitized, liquid,
n.o.s. with not more than 30% nitroglycerin, by mass, 3, PG II''.
PHMSA expects that assigning this special provision will enhance
safety by ensuring that both solid and liquid desensitized explosives
are subject to uniform performance standards for the diluent during
transportation.
PHMSA proposes to make corrections to multiple HMT entries that
were inadvertently modified in previous rulemakings. Specifically,
PHMSA proposes to remove IP8 from column (7) of the HMT for the
following assigned UN numbers: ``UN2246 Cyclopentene'', ``UN1593,
Dichloromethane,'' ``UN1164 Dimethyl sulfide,'' ``UN1891, Ethyl
bromide,'' ``UN2622, Glycidaldehyde,'' ``UN2288, Isohexenes,''
``UN2612, Methyl propyl ether,'' ``UN2460, 2-Methyl-2butene,'' ``UN1234
Methylal,'' ``UN1265, Pentanes, PGII,'' and ``UN1278, 1-Chloroproane.''
IP8 states that ammonia solutions may be transported in rigid or
composite plastic IBCs (31H1, 31H2 and 31HZ1) that have successfully
passed, without leakage or permanent deformation, the hydrostatic test
specified in Sec. 178.814 of the HMR at a test pressure that is not
less than 1.5 times the vapor pressure of the contents at 55 [deg]C
(131 [deg]F). IP8 was meant to be assigned to ammonia solutions, but
due to an editorial error, IP8 was assigned to these UN numbers, which
are not ammonia solutions.
Finally, for ``UN2555, Nitrocellulose with water with not less than
25 percent water, by mass, 4.1, PG II'' and ``UN2556 Nitrocellulose
with alcohol with not less than 25 percent alcohol by mass, and with
not more than 12.6 percent nitrogen, by dry mass, 4.1, PG II,'' PHMSA
proposes to assign Special Provision 197. This special provision was
inadvertently removed from these entries in the HM-215Q final rule.\20\
PHMSA expects that this correction will provide enhanced safety by
removing conflicting packaging provisions from these entries.
---------------------------------------------------------------------------
\20\ 89 FR 25434 (Apr. 10, 2024).
---------------------------------------------------------------------------
Column (8) Packaging
Section 172.101(i) explains the purpose of column (8) in the HMT.
Columns (8A), (8B), and (8C) specify the applicable sections for
exceptions, non-bulk packaging requirements, and bulk packaging
requirements, respectively. Columns (8A), (8B), and (8C) are completed
in a manner which indicates that ``Sec. 173'' precedes the designated
numerical entry. Column (8A) contains exceptions from some of the
requirements of the HMR. The referenced exceptions are in addition to
those specified in subpart A of part 173 and elsewhere in the HMR. The
word ``None'' in this column means no packaging exceptions are
authorized, except as may be provided by special provisions in column
(7).
For ``UN3423, Tetramethylammonium hydroxide, solid,'' and based on
the proposed classification changes to a Division 6.1 (8), PG I
material, PHMSA proposes to remove the ``154'' in column (8A), which
currently directs the reader to exceptions for Class 8 (corrosive
materials) and to replace it with ``None.'' In addition, in column
(8B), ``213'' would be replaced by ``211'' to direct users to the
requirements for authorized non-bulk packagings for solid hazardous
materials in PG I in Sec. 173.211. Lastly, in column (8C), ``240''
would be replaced with ``242'' to direct users to requirements for
authorized bulk packagings for certain medium hazard liquids and
solids, including solids with dual hazards. PHMSA expects that these
changes will improve safety by providing more appropriate packaging
requirements based on the newly identified hazards posed by this
material.
Column (9) Quantity Limitations
Section 172.101(j) explains the purpose of column (9) in the HMT.
Column (9) specifies quantity limitations for packages transported by
air and rail. Column (9) is divided into two columns: column (9A)
provides quantity limits for passenger aircraft/rail, and column (9B)
provides quantity limits for cargo aircraft.
To align with changes adopted in the 2025-2026 edition of the ICAO
Technical Instructions, PHMSA proposes to amend the quantity
limitations for TMAH solids (UN3423), consistent with reclassification
of this entry. With the proposed new Division 6.1, PG I primary hazard
for UN3423, different quantity limitations are required. PHMSA proposes
to replace ``15 kg'' with ``1 kg'' in column (9A) and to replace ``50
kg'' with ``15 kg'' in Column (9B), which is consistent with the
quantity limits for other Division 6.1, PG I entries in the HMT. PHMSA
expects this proposed change to improve safety by appropriately
limiting the quantities of this material when transported by rail and
air.
Column (10) Vessel Stowage
Section 172.101(k) explains the purpose of column (10) of the HMT
and prescribes the vessel stowage and segregation requirements for
specific entries. Column (10) is divided into two columns: column (10A)
[Vessel stowage] specifies the authorized stowage locations on board
cargo and passenger vessels; and column (10B) [Other provisions]
specifies special stowage and segregation provisions. The meaning of
each code in column (10B) is set forth in Sec. 176.84.
For ``UN1791, Hypochlorite solutions, PG III,'' PHMSA proposes to
make a correction to the HMT entry. In its HM-215Q rulemaking, PHMSA
removed the stowage codes 53 and 58, which require stowage ``separated
from alkaline compounds'' and ``separated from cyanides,''
respectively.\21\ These stowage codes were intended to be applied to
several HMT entries to ensure proper segregation between acids and both
amines and cyanides, but should not have included ``UN1791,
Hypochlorite solutions.'' When this removal of the stowage codes 53 and
58 was implemented in HM-215Q, PHMSA inadvertently omitted the removal
of the aforementioned stowage codes for the PG III entry. Therefore,
PHMSA proposes to remove the stowage codes 53 and 58 from column (10B)
of ``UN1791, Hypochlorite solutions, PG III.'' PHMSA expects that this
correction will remove the burden faced by shippers who have had to
segregate hypochlorite solutions for compliance with the HMR, which is
inconsistent with the requirements of the IMDG Code.
---------------------------------------------------------------------------
\21\ 89 FR 25434 (Apr. 10, 2024).
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For ``UN2067, Ammonium nitrate-based fertilizer,'' PHMSA proposes
to assign stowage code 116 in column (10B) (as proposed to be amended,
see discussion in Section-by-Section Review of Sec. 176.84). This
stowage code is currently assigned to ``UN1942, Ammonium nitrate, with
not more than
[[Page 6011]]
0.2% combustible substances, including any organic substance calculated
as carbon, to the exclusion of any other added substance,'' and PHMSA
proposes to also assign it to ``UN2067, Ammonium nitrate-based
fertilizer.'' This change in stowage requirements was adopted in
Amendment 42-24 of the IMDG Code because these substances have similar
chemical properties, pose similar hazards, may be transported in the
same way (e.g., conventional reefer ship, and stored in areas that
contain multiple compartments or on vessels with tween deck storage).
PHMSA expects this new assignment to provide clarity and consistent
direction regarding how these ammonium-based hazardous materials are to
be stowed to ensure vessel safety.
For ``UN2303, Isopropenylbenzene,'' PHMSA proposes to assign
stowage code 25 in column (10B). This stowage code requires that the
hazardous material be ``protected from sources of heat.'' This new
stowage requirement for UN2303 was added in Amendment 42-24 to the IMDG
Code because the material is liable to polymerize and is generally
stabilized with a small quantity of 4-tert-butylcatechol, which should
be stored at temperatures not exceeding 30 [deg]C. PHMSA agrees with
the addition of this extra stowage requirement and expects that
protecting the material from sources of heat will enhance safety by
ensuring that the stabilization methods applied to these packages will
not become ineffective during transport by vessel.
For ``UN3129, Water-reactive liquid, corrosive, n.o.s., PG II and
III,'' ``UN3130, Water-reactive liquid, toxic, n.o.s., PG II and III,''
and ``UN3148, Water-reactive liquid, n.o.s., PG I, II, and III,'' PHMSA
proposes to revise vessel stowage requirements in column (10A).
Currently, these entries are assigned stowage category ``E.'' Stowage
category ``E'' indicates that a material may be stowed ``on deck'' or
``under deck.'' PHMSA proposes to change the code in column (10A) for
these entries to stowage category ``D.'' This would indicate that these
entries must be stowed on deck only and would not be permitted to be
stowed under deck. As these materials will not be allowed to be stowed
under deck, PHMSA also proposes to revise column (10B) by removing
assignment of stowage code ``85,'' which states that a material stowed
under deck must be in a mechanically ventilated space, from the entries
UN3129 and UN3130. PHMSA also proposes to add new stowage code ``160''
to column (10B) to the entries UN3129, UN3130, and UN3148. This new
code will indicate that these materials must be stowed away from
potential sources of ignition. These changes in stowage requirements
mirror those adopted in Amendment 42-24 to the IMDG Code to address a
hazard communication conflict.
Currently, there is no general ``n.o.s.'' entry for liquids
classified as a Division 4.3 (dangerous when wet) that also meet the
flammable liquid definition (i.e., water-reactive liquids, flammable,
n.o.s.), because the Division 4.3 classification would take precedence
in hazard classification in accordance with Sec. 173.2. Therefore,
shippers are required to classify and to describe these materials as
``UN3148, Water-reactive liquid, n.o.s.,'' which does not provide any
indication that the liquid also meets a flammable liquid definition.
This requires carriers to assess the flashpoint of a Division 4.3
liquid described as ``UN3148 Water-reactive liquid, n.o.s.,'' ``UN3130,
Water-reactive liquid, toxic,'' or ``UN3129, Water-reactive liquid,
corrosive, n.o.s.,'' by requesting a safety data sheet, which imposes
avoidable administrative burdens for both carriers and shippers. To
address this, the IMO revised the stowage categories for the entries
discussed from ``E'' to ``D,'' which would prohibit these materials
from being stored under deck regardless of their flash point. This
amendment would alleviate the burden for carriers to determine material
flashpoints to identify their prescribed stowage locations. PHMSA
agrees with these revisions and proposes to amend the entries as
discussed above.
The IMDG code also requires packages containing flammable gases and
flammable liquids having a flashpoint of less than 23 [deg]C to be
stowed away from potential sources of ignition. However, there are
currently no stowage codes that memorialize this requirement. To
address this, the IMDG code added new stowage code ``SW31,'' which
indicates that flammable liquids having a flashpoint of less than 23
[deg]C must be stowed away from potential sources of ignition, and
assigned it to UN3129, UN3130, and UN3148. PHMSA expects that
harmonization with these vessel stowage amendments will alleviate
carriers from having to determine a material's flash point and its
correct stowage location.
For ``UN3536, Lithium batteries installed in cargo transport unit
lithium ion batteries or lithium metal batteries,'' PHMSA proposes to
change the code in column (10A) for this entry to stowage category
``D.'' This code would mean that this entry must be stowed ``on deck
only'' on a cargo vessel or on a passenger vessel carrying a number of
passengers limited to not more than the larger of 25 passengers, or one
passenger per each 3 meters of overall vessel length, but the material
is prohibited on a passenger vessel in which the limiting number of
passengers is exceeded. For column (10B), PHMSA proposes to add Codes
``25'' and ``40.'' As stated in Sec. 176.84(b), Code ``25'' means that
the material must be protected from sources of heat, and Code ``40''
means that the material must be stowed ``clear of living quarters.''
The thirty-ninth session of the CCC finalized these same changes as
adopted in Amendment 42-24 of the IMDG Code for UN3536 based on
position papers showing significant safety concerns with the way
``lithium battery energy storage cabinets'' were being regulated for
stowage aboard vessels. These papers demonstrated, through simulations
of fires and explosions involving the ``energy storage cabinets,'' that
a significant risk of rupture of the hull structure of ships exists
when these containers are stowed in certain positions below deck.
Further, it was shown that there was significant risk to the life and
safety of the crew when fires involving these containers occur and they
are stowed under deck. For these reasons, the CCC, as provided for in
Amendment 42-24 of the IMDG Code, adopted provisions that require
stowage on deck, and in some cases, a prohibition of transport on
certain vessels. Amendment 42-24 of the IMDG Code also adopted
provisions that would add safety precautions by protecting the
containers from sources of heat and requiring stowage clear of living
quarters. PHMSA expects that these new requirements will address the
hazards identified by the simulations discussed in these papers and
incidents of thermal runaway associated with the transportation of
``lithium battery energy storage cabinets.''
For ``UN3555, Trifluoromethyltetrazole-sodium salt in acetone, with
not less than 68% acetone, by mass, 3, PG II'' (TFMT-Na), PHMSA
proposes to add two new vessel stowage and handling codes. In Amendment
42-24 to the IMDG Code, under column 16a of the DGL, this new entry was
assigned four stowage and handling codes which require for UN3555 that:
it must be protected from sources of heat (SW1); cargo transport units
be shaded from direct sunlight (SW11); it must be stored in cool
ventilated space (H3); and that it must be kept as cool as reasonably
practicable (H2). PHMSA is assigning codes ``12'' and ``25,'' which
correspond to H2 and SW1, respectively. However, the HMR do not have
corresponding vessel stowage and handling codes for ``SW11''
[[Page 6012]]
and ``H3,'' therefore, PHMSA proposes harmonizing with the IMDG Code to
add corresponding provisions by creating two new vessel stowage codes,
Code 158 and Code 159. Code 158, like SW11, would instruct that ``Cargo
transport units shall be shaded from direct sunlight. Packages in cargo
transport units shall be stowed to allow for adequate air circulation
throughout the cargo.'' Code 159, like H3, would instruct ``During
transport, it should be stowed (or kept) in a cool ventilated place.''
PHMSA expects that these stowage and handling provisions will provide
the appropriate level of safety for the transport of this material on
vessels.
For ``UN3560, Tetramethylammonium hydroxide aqueous solution with
not less than 25 percent tetramethylammonium hydroxide,'' PHMSA
proposes to add a new stowage code ``D'' in column (10A). This code
would mean that the material must be stowed ``on deck only'' on a cargo
vessel, or on a passenger vessel carrying a maximum of 25 passengers,
or one passenger for each three meters of overall vessel length, but if
the limiting number of passengers is exceeded the material is
prohibited onboard the vessel. This new stowage location aligns with
provisions in Amendment 42-24 to the IMDG Code. In addition, in column
(10B), PHMSA proposes to assign stowage code ``52,'' which states that
materials must be stowed ``separated from'' acids. Section
176.83(c)(2)(iii) defines ``separated from'' for ``on deck'' stowage
(category D) as separated by a distance of at least six meters (20
feet) horizontally. The assignment of these new stowage and handling
requirements aligns with provisions in Amendment 42-24 to the IMDG
Code. PHMSA expects this proposed change to improve safety by ensuring
that this material is stowed in an appropriate location and under
appropriate conditions, such as being separated from packages
containing acids when transported by vessel.
Section 172.102 (Special Provisions)
Section 172.102 lists special provisions applicable to the
transportation of specific hazardous materials. Special provisions
contain various provisions, including packaging requirements,
prohibitions, and exceptions applicable to particular quantities or
forms of hazardous materials. PHMSA proposes the following additions
and revisions to the special provisions in this section:
Special Provision 43
PHMSA proposes to modify Special Provision 43, which is assigned to
``UN3270, Nitrocellulose membrane filters, with not more than 12.6%
nitrogen, by dry mass'' in the HMT. These materials are most notably
used in rapid test devices for infectious diseases like COVID-19,
influenza, hepatitis, malaria, borreliosis, and other diseases, and as
substrates for bioanalytical tests as well as pregnancy tests. Special
Provision 43 states that to use this HMT entry nitrocellulose membrane
filters--including paper separators and coating or backing materials--
present in transport must not be able to propagate a detonation as
tested by UN Manual of Tests and Criteria, Part I, Test Series 1(a).
Special Provision 43 further states that nitrocellulose (NC) membrane
filters in the form in which they are to be transported that do not
meet the criteria for a Division 4.1 material, based on suitable
burning rate tests and testing in accordance with the UN Manual of
Tests and Criteria, Part III, are not subject to the HMR. Finally, NC
membrane filters, each with a mass not exceeding 0.5 g, are not subject
to the HMR when contained individually in an article or a sealed
packet.
To further facilitate the transport of these items, which are often
used in medical testing, the 23rd revised edition of the UN Model
Regulations includes a new special provision assigned to UN3270 that
adds conditions for exception from regulation without the need for
testing. PHMSA proposes to adopt the provisions of this new special
provision as part of Special Provision 43 in the HMR instead of a
wholly separate special provision. Specifically, the special provision
in the UN Model Regulations states that for a NC membrane filter with a
nitrocellulose content that does not exceed 53 g/m\2\, and where the
net mass does not exceed 300 g per inner packaging, the NC membrane
filter is not subject to regulation under certain conditions. The
conditions are that they are packed with paper separators with a
minimum of 80 g/m\2\ placed between each layer of NC membrane filters;
and that they are packed to maintain alignment of the NC membrane
filters and paper separators in accordance with three distinct
configurations. This exception was adopted based on additional tests
showing that NC membrane filters with a NC content less than 53 g/m\2\
and an NC net weight not exceeding 300 g per inner packaging do not
propagate a detonation and had burn rates justifying exclusion from
classification as a Division 4.1 flammable solid in the
configuration(s) defined by the provision. As stated previously, PHMSA
proposes to adopt the conditions of the UN Model Regulation special
provision as part of SP 43 and expects that doing so will facilitate
the transport of these filters and reduce the burden of requesting a
competent authority approval for transportation of each NC membrane
filter type. In addition, this provision will improve the availability
of the NC membrane filters for important medical devices, such as rapid
test devices for determination of COVID-19 infections. PHMSA expects
that the reduced regulatory burden for these products will translate to
reduced costs for consumers of many commonly used products in the
American pharmacological market.
Special Provision 134
Special Provision 134, which is assigned to ``UN3171, Battery-
powered vehicle or Battery-powered equipment,'' currently indicates
that the use of UN3171 only applies to vehicles or equipment powered by
wet batteries, sodium batteries, lithium metal batteries, or lithium
ion batteries that are transported with such batteries installed.
However, with the introduction of three specific proper shipping names
for battery-powered vehicles, the range of hazardous materials that can
be transported under UN3171 is reduced to vehicles and equipment
powered by wet batteries that are transported with such batteries
installed. PHMSA proposes to amend Special Provision 134 to clarify
that vehicles powered by lithium ion, lithium metal, or sodium ion
batteries must be assigned to ``UN3556, Vehicle, lithium ion battery
powered,'' ``UN3557, Vehicle, lithium metal battery powered,'' and
``UN3558, Vehicle, sodium ion battery powered vehicle,'' respectively,
and to assign this special provision to these entries on the HMT. PHMSA
also proposes to add language regarding vehicles transported in
packagings to reiterate that, except for the battery, some parts of
battery powered vehicles may be detached from the frame of the vehicle
to fit in the outer packaging. This language reiterates language
currently in Sec. 173.220, which states that if a battery is removed
from a battery powered vehicle (engines and machinery), and is packed
in the same outer packaging, the package must be consigned as ``UN3481,
Lithium ion batteries packed with equipment,'' ``UN3091, Lithium metal
batteries packed with equipment;'' or ``UN3552, Sodium ion batteries
packed with equipment, with organic
[[Page 6013]]
electrolyte.'' As this is only a clarifying editorial amendment, PHMSA
expects the change will enhance safety by facilitating the proper
description and classification of these vehicles and does not expect
that this change will result in any additional costs for the regulated
community.
Special Provision 160
Special Provision 160 is assigned to HMT entry ``UN3268, Safety
devices, electrically initiated, 9,'' and outlines conditions and
criteria for use of the entry. Consistent with discussions of proposed
changes to the HMR regarding fire suppressant dispersing devices in
Sec. Sec. 172.101, 173.62, and 173.169, PHMSA proposes to revise
Special Provision 160 to include a statement to clarify that the HMT
entry for ``UN3268, Safety devices'' does not apply to fire suppressant
dispersing devices described in Sec. 173.169, specifically, those
articles that are properly classed and described as ``UN3559, Fire
suppressant dispersing devices.'' PHMSA expects that these changes will
enhance safety by facilitating the proper classification of these
devices.
Special Provision 162
Special Provision 162, which is assigned to HMT entries that are
explosive materials desensitized by liquid (typically water) and
classified as a Division 4.1 flammable solid, specifies that these
materials may be transported as a Division 4.1 only if packed so that
at no time during transport will the percentage of diluent (i.e., the
liquid used to desensitize the explosive material) fall below the
percentage that is stated in the shipping description. While developing
provisions for UN3555, TFMT-Na, a flammable liquid desensitized
explosive (as discussed in the Section-by-Section review), the UNSCOE
determined that there are no comparable provisions for entries of
flammable liquid desensitized explosives classified as Class 3
flammable liquids. Consequently, the UNSCOE determined that this
provision (Special Provision 28 in the UN Model Regulations) should be
amended to be applicable to flammable liquid desensitized explosives.
PHMSA agrees with the UNSCOE and proposes to amend the text of Special
Provision 162 to ensure desensitized explosives to be transported under
the provisions of Class 3 or Division 4.1, as appropriate, are packed
so that the percentage of diluent will not fall below that is stated,
at any time during transportation. In addition, the amendment would
require, in cases where the diluent is not stated, that the substance
be packed so that the amount of explosive substance does not exceed the
stated value. PHMSA expects that these changes will enhance safety by
providing uniform requirements for the transport of desensitized
explosives.
Special Provision 181
For shippers of lithium ion or lithium metal batteries that are
``contained in'' or ``packed with equipment,'' Special Provision 181
instructs that there are certain requirements when a package includes a
combination of these lithium battery packaging configurations. This
special provision requires that: the packages meet all applicable
requirements in Sec. 173.185; packages cannot exceed the quantity
limits in columns (9A) and (9B) for passenger aircraft or cargo
aircraft, as applicable; the package must be marked for lithium ion or
lithium metal batteries packed with equipment; and the shipping paper
must indicate the entry(ies) for lithium metal or lithium ion batteries
(or a combination of the two) packed with equipment. With the addition
of new entries for sodium ion batteries contained in and packed with
equipment, and the application of provisions for lithium batteries to
sodium ion batteries, PHMSA proposes to make this special provision
applicable to lithium batteries contained in equipment and packed with
equipment, as well as to sodium ion batteries contained in equipment
and packed with equipment. PHMSA also proposes to assign Special
Provision 181 to the following new HMT entries: ``UN3552, Sodium ion
batteries contained in equipment with organic electrolyte'', and
``UN3552, Sodium ion batteries packed with equipment with organic
electrolyte.''
This special provision ensures that the appropriate hazard
communication for packages containing batteries both contained in and
packed with equipment, indicating the slightly greater transport risk
when batteries are packed with equipment versus when batteries are
contained in equipment. PHMSA expects that extending this requirement
will improve the level of safety achieved for lithium batteries to
sodium ion batteries. Though the ICAO Dangerous Goods Panel (DGP) did
not consider this change for the 2025-2026 ICAO TI, PHMSA expects that
this requirement will be proposed and adopted in upcoming DGP meetings
to provide consistency in the requirements for sodium ion batteries.
PHMSA solicits comments on whether codifying this provision should be
delayed until it is adopted in other international standards.
Special Provision 234
PHMSA proposes to add a new Special Provision 234 to provide
packaging requirements for the new HMT entry, ``UN3555,
Trifluoromethyltetrazole, sodium salt (TFMT-Na).'' This special
provision mirrors the corresponding packaging and modal transport
provisions in the UN Model Regulations. Specifically, PHMSA proposes
that authorized packaging for TFMT-Na in acetone must be designed and
constructed to prevent loss of the content of the phlegmatizer (i.e.,
the acetone), must be transported in an upright position, and must be
lead free. In addition, packaging must be limited to a maximum capacity
of 250 liters (66 gallons).
Trifluoromethyltetrazole, sodium salt (TFMT-Na) in acetone is a
desensitized explosive compound used as a precursor material for
production of a new insecticide. Due to the explosive properties of the
dry substance, it is handled and transported as a homogenous solution
in acetone and currently is transported under a generic n.o.s. HMT
entry. Because of its unique properties and expected increased use in
insecticide manufacturing, the UNSCOE agreed to create a new entry on
the DGL to facilitate its transport. As discussed earlier,
Trifluoromethyltetrazole, sodium salt (TFMT-Na) is a product used in
new products, such as insecticides. PHMSA expects that the addition of
this new packaging provision will contribute to emerging industries by
facilitating the transport of this material while providing a high
level of safety.
Special Provision 252
PHMSA proposes to add a new Special Provision 252 assigned to
``UN2426, Ammonium nitrate, liquid (hot concentrated solution).'' This
special provision would outline conditions under which solutions of
ammonium nitrate can be transported under the HMT entry UN2426.
According to this special provision, use of this entry would be based
on concentration, water content, combustible material content, chlorine
content, pH level, and temperature. Special Provision 252 would also
outline criteria that ammonium nitrate solutions must meet to be
excepted from regulation. The characteristics outlined in part (1) of
Special Provision 252 reflect the existing requirements for transport
of UN2426 in the Agreements Concerning the International Carriage of
Dangerous Goods by Rail (RID) and by Road (ADR) and the IMDG Code.
Given that these standards for transportation of
[[Page 6014]]
UN2426 are already recognized in the RID/ADR and IMDG Codes,
incorporation of Special Provision 252 would provide clarity by
bringing these standards directly into the HMR. Adopting these
prescriptive requirements would add clarity to the classification of
the material by communicating the thresholds above which the material
is classified as hazardous. These requirements were also adopted in the
23rd revised edition of the UN Model Regulations to harmonize the
transport conditions multimodally. PHMSA expects that adopting this
special provision in the HMR will facilitate the movement of these
solutions and improve safety by providing additional clarity on the
classification of ammonium nitrate solutions.
Special Provision 328
Special Provision 328 instructs shippers on how to describe fuel
cell systems containing lithium metal or lithium ion batteries. PHMSA
proposes to make Special Provision 328 applicable to sodium ion
batteries that are a component of a fuel cell system. Currently, the
special provision only addresses lithium ion batteries and lithium
metal batteries that are components of fuel cell systems. PHMSA expects
this revision will help to ensure that fuel cell systems with sodium
ion batteries are properly classified and that their hazards are
properly communicated. Further, this revision harmonizes the HMR with
the UN Model Regulations and ICAO Technical Instructions for the
adoption of new provisions for sodium ion batteries.
Special Provision 360
Special Provision 360, which is assigned to ``UN3091, Lithium metal
batteries contained in equipment'' and ``UN3481, Lithium ion batteries
contained in equipment,'' currently indicates that vehicles powered
solely by lithium batteries must be transported as ``UN3171, Battery-
powered vehicle.'' This special provision serves to clarify that these
batteries should be classified as ``UN3171, Battery-powered vehicle,''
rather than ``UN3091, Lithium metal batteries contained in equipment,''
or ``UN3481, Lithium ion batteries contained in equipment,'' if the
battery provides motive power for a vehicle. As discussed in the
amendments to the HMT (see the Section-by-Section Review in Section
172.101), in light of PHMSA's proposal to add new entries specifically
for vehicles powered by lithium ion batteries, lithium metal batteries,
and sodium ion batteries to the HMT, PHMSA proposes to amend Special
Provision 360 to stipulate that vehicles powered by these batteries
must be assigned to ``UN3556, Vehicle, lithium ion battery powered,''
``UN3557, Vehicle, lithium metal battery powered,'' or ``UN3558,
Vehicle, sodium ion battery powered,'' respectively. This proposal
aligns with the proposed amendment to Special Provision 134 (discussed
above). PHMSA expects that these changes will enhance safety by
facilitating the proper classification of these vehicles. PHMSA does
not anticipate there will be any costs associated with this
clarification as shippers would be provided time to exhaust stocks of
existing markings or labels with the currently used PSN.
Special Provision 365
PHMSA proposes to modify Special Provision 365 to include a
reference to the proposed new HMT entry ``UN3554, Gallium contained in
manufactured articles,'' and to assign this special provision to
``UN2803, Gallium.'' Currently, Special Provision 365 is assigned to
``UN2809, Mercury,'' which provides instructions to facilitate proper
classification of mercury containing articles by directing users to
``UN3506, Mercury contained in manufactured articles'' and its
associated provisions rather than UN2809, which is for elemental
mercury. PHMSA proposes to amend the special provision to provide the
same clarification for gallium by adding a reference to ``UN3554,
Gallium contained in manufactured articles,'' and assigning it to the
UN entry for elemental gallium, ``UN2803.'' PHMSA expects that this
change will facilitate the transport of articles and manufactured items
containing gallium and prevent avoidable costs to shippers. PHMSA
expects that this will ensure these items are transported under the
appropriate proper shipping name and that they will not be packaged and
transported in accordance with the elemental gallium (UN2803)
provisions for which there are fewer exceptions.
Special Provision 371
PHMSA proposes to revise Special Provision 371 by removing the
requirement to follow the witness screen setup requirements provided in
paragraph 16.6.1.3.5 of the UN Manual of Tests and Criteria, which
conflicts with an exception from the requirement to have a witness
screen as specified in 16.6.1.2(g). Special Provision 371 is assigned
to ``UN3164, Articles, pressurized pneumatic or hydraulic containing
non-flammable gas,'' and contains provisions to determine whether
articles containing a small pressure receptacle with a release device
can be transported under the entry ``UN3164, Articles, pressurized
pneumatic or hydraulic containing non-flammable gas.'' Paragraph (a)(6)
in Special Provision 371 requires an external fire (bonfire) test that
follows the provisions of paragraph 16.6.1.2 (but specifically excepts
paragraph (g)), as well as the provisions of 16.6.1.3.1 through
16.6.1.3.6, 16.6.1.3.7(b), and 16.6.1.3.8 of the UN Manual of Tests and
Criteria. The requirement to follow 16.6.1.3.5, which outlines how to
erect and place witness screens, conflicts with the exception from the
requirement to have a witness screen, as provided in letter (g) of
paragraph 16.6.1.2. To resolve that conflict, the UNSCOE removed the
requirements to follow 16.6.1.3.5. PHMSA agrees with this correction
and expects that it will facilitate the proper testing and
classification of these materials.
Special Provision 379
Special Provision 379 provides conditions for exception from full
regulation under the HMR for anhydrous ammonia adsorbed or absorbed on
a solid contained in ammonia dispensing systems or receptacles intended
to form part of such systems. Among these conditions, Special Provision
379 requires that receptacles containing adsorbed or absorbed ammonia
must be made of a material compatible with ammonia as specified in ISO
11114-1:2012(E), ``Gas cylinders--Compatibility of cylinder and valve
materials with gas contents--Part 1: Metallic materials,'' and an
addendum published in 2017, ISO 11114-1:2012/Amd 1:2017(E). PHMSA
proposes to revise Special Provision 379 to require receptacles to be
made of compatible material as specified in updated ISO 11114-
1:2020(E). This document was updated as part of ISO's regular periodic
review and adopted for reference in the 23rd revised edition of the UN
Model Regulations. PHMSA expects the use of these updated documents
would allow safe transport of a wider variety of gases in newly
developed types of metallic cylinders and valves without compromising
safety.
Special Provision 389
Special Provision 389 provides packaging instructions and hazard
communication requirements for ``UN3536, Lithium batteries installed in
cargo transport unit lithium ion batteries or lithium metal batteries,
9.'' PHMSA proposes to revise this special provision to provide clarity
regarding the emergency response information that
[[Page 6015]]
accompanies shipments of UN3536. Specifically, PHMSA proposes that the
emergency response information must specifically identify the
predominant type of energy storage battery installed in the unit (e.g.,
lithium ion batteries) and provide information on immediate methods for
handling fires that may take place in these units.
On May 11, 2020, PHMSA published final rule HM-215O--a previous
iteration of our recurring biennial rulemaking series to maintain
harmonization with international regulations and standards.\22\ One of
the amendments finalized in HM-215O adopted a new entry in the HMT for
the transportation of lithium battery energy storage systems that are
transported in the form of a cargo transport unit. UN3536, Lithium
batteries installed in cargo transport unit lithium ion batteries or
lithium metal batteries, 9'' is intended to facilitate the
transportation of large-scale battery energy storage systems. These
devices are often used to provide electrical power in harsh, ``off-
grid'' locations, or as part of an electrical utility facility that
stores energy for subsequent use in the electrical grid.\23\ PHMSA's
understanding is that shipments assigned UN3536 are for systems that
primarily contain rechargeable lithium ion batteries as the means of
energy storage.\24\ PHMSA seeks comment on our understanding of the
types of lithium batteries transported using the UN3536 entry.
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\22\ 85 FR 27810 (May 11, 2020).
\23\ U.S. Energy Information Administration, Electricity
explains--Energy storage for electricity generation (Last accessed
Nov. 19, 2025), available at: <a href="https://www.eia.gov/energyexplained/electricity/energy-storage-for-electricity-generation.php">https://www.eia.gov/energyexplained/electricity/energy-storage-for-electricity-generation.php</a>.
\24\ U.S. Dept. of Energy, U.S. DOE Energy Storage Handbook
(last accessed November 19, 2025), available at: <a href="https://www.sandia.gov/ess/publications/doe-oe-resources/eshb">https://www.sandia.gov/ess/publications/doe-oe-resources/eshb</a>.
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Currently, the required portion of the proper shipping name for
UN3536--Lithium batteries installed in cargo transport unit--does not
distinguish between lithium ion and lithium metal batteries. Instead,
this distinction is made through italicized text in the HMT, which is
not required to appear on the shipping paper or emergency response
information. PHMSA's Emergency Response Guidebook (ERG), a resource for
use during the initial phase of a transport incident involving
hazardous materials, provides differing guidance for fires involving
lithium ion and lithium metal batteries. The ERG recommends applying
water to a lithium ion battery fire to cool surrounding cells, while
the ERG indicates that water and foam should not (emphasis added) be
applied to a lithium metal battery fire. The entry in the ERG for
UN3536 directs the reader to different guide pages depending on the
type of battery used in the system--i.e., Guide 147, if the cargo
transport unit contains lithium ion batteries, or Guide 138, if the
cargo transport unit contains lithium metal batteries.\25\ Furthermore,
a vehicle transporting UN3536 is required to carry emergency response
information (ERI) with the shipping paper that can be used in the
mitigation of an incident involving UN3536, including immediate methods
to handle fires.\26\ This information must provide the proper
instructions for emergency response for the specific type of lithium
battery technology contained in the cargo transport unit.
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\25\ PHMSA, Emergency Response Guidebook 2024, available at:
<a href="https://www.phmsa.dot.gov/training/hazmat/erg/erg2024-pdf-accessible-english">https://www.phmsa.dot.gov/training/hazmat/erg/erg2024-pdf-accessible-english</a>.
\26\ 49 CFR part 172, subpart G.
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A July 2024 incident in Baker, California, involving a motor
vehicle transporting UN3536 and resulting in a fire, demonstrates the
importance of providing accurate emergency response information. PHMSA
observed that the information contained in the proper shipping name and
the ERG guidance created confusion for emergency responders in an
accident scenario involving the transportation of a battery energy
storage system.\27\ In particular, the UN identification (ID) number
displayed on the cargo transport unit and the mandatory information
from the shipping paper (i.e., UN3536, Lithium batteries installed in
cargo transport unit) did not indicate whether the cargo transport unit
contained lithium ion batteries or lithium metal batteries. Emergency
responders were unclear with respect to immediate measures to mitigate
the incident due to uncertainty on whether or not they should apply
water during the initial stages of the fire. PHMSA is concerned that
similar situations may reoccur during the initial response to future
incidents involving UN3536, leading to a reduction in emergency
response effectiveness, and increased risks to persons, property, and
the environment.
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\27\ Caltrans, Caltrans Statement on San Bernardino County I-15
Fire, available at: <a href="https://dot.ca.gov/news-releases/news-release-2024-027">https://dot.ca.gov/news-releases/news-release-2024-027</a>.
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PHMSA proposes to clarify the requirements for the ERI that
accompanies the shipment of UN3536 to improve emergency response.
Specifically, PHMSA proposes to revise Special Provision 389 to state
that the ERI that accompanies the shipment must identify the
predominant type of batteries in the cargo transport unit (i.e.,
lithium ion or metal batteries) and provide specific instructions that
can be used in the mitigation of an incident, including a fire,
involving the unit. PHMSA also proposes an editorial revision to create
a paragraph structure for Special Provision 389 to clarify for the
reader. PHMSA does not anticipate there will be any costs associated
with this clarification, which aligns with existing emergency response
information requirements (see Sec. 172.602(a)). PHMSA expects this
revision will result in benefits through increased compliance with the
existing requirement, which will result in decreased risks to emergency
responders' personal safety, and an improved ability to identify and to
apply the correct emergency response actions during an incident. PHMSA
seeks comment on these expectations.
Separately, PHMSA intends to work with the UNSCOE to pursue
internationally harmonized changes to the HMT to create separate UN ID
number and proper shipping name entries for cargo transport units
containing lithium ion or lithium metal, as well as a new entry for
cargo transport units containing sodium ion batteries to improve hazard
communication for these energy storage systems. Following the
completion of that work, PHMSA will consider--in a future separate
rulemaking--revising the HMT to harmonize with those changes to improve
emergency response without impeding international transportation of
these devices. Until more specific proper shipping names and UN numbers
are adopted to reflect predominant battery (i.e., lithium metal or
lithium ion) in cargo transport units specifically, PHMSA intends to
consider the predominant battery to be the battery that provides
electrical power when the container is in use and supplying power to
the grid. PHMSA's understanding is that typically the main source of
power for these units is a lithium ion battery because these battery
types may be recharged which allows them to be used more than once.
Special Provision 400
PHMSA proposes to add a new Special Provision 400 and to assign it
to the following new HMT entries: ``UN3551, Sodium ion batteries with
organic electrolyte,'' ``UN3552, Sodium ion batteries contained in
equipment with organic electrolyte,'' and ``UN3552, Sodium ion
batteries packed with equipment, with organic electrolyte.'' This
special provision will allow shippers to offer sodium ion batteries for
transportation other than by air without being further subject to
requirements of the HMR if certain
[[Page 6016]]
conditions are met. A similar special provision was adopted in the 23rd
revised edition of the UN Model Regulations and Amendment 42-24 of the
IMDG Code. As discussed in Sec. 172.101 of the Section-by-Section
Review, sodium ion batteries, unlike lithium ion batteries, can be
discharged to zero volts without affecting the performance of the cell.
This means batteries using sodium ion technology can be stored and
transported in a completely discharged state, posing no risk from
electrical energy. For that reason, PHMSA believes that adding this
special provision to provide an exception from all other HMR
requirements (except when transported by air), given that certain
conditions are still in place, is appropriate and will maintain safety
during transportation of these batteries.
At the 29th meeting of the ICAO DGP, the addition of this special
provision to the 23rd revised edition of the UN Model Regulations was
discussed but ultimately not adopted into the 2025-2026 ICAO Technical
Instructions. The DGP stated that it could be confusing to require a
battery mark on the packaging, which could lead to disruptions in the
acceptance process. The DGP also stated that it would be difficult for
anyone other than the manufacturer to know the other hazardous
materials that are components of the battery, and to comply with the
condition of the special provision that requires the components to be
authorized as limited quantities. Therefore, PHMSA proposes to make
this special provision authorized for all modes of transportation
except for air.
For modes other than air transportation, Special Provision 400 will
instruct those offering sodium ion cells and batteries, including those
packed with, or contained in, equipment, that those cells and batteries
will not be subject to the HMR if: (1) they are short-circuited to a
point that they contain no electrical energy; (2) they meet some of the
general design criteria for batteries in Sec. 173.185(a); (3) the
package is marked with the battery mark; (4) the package, except for
cells or batteries contained in equipment, is capable of withstanding a
drop test; (5) the cells and batteries contained in equipment are
protected from damage; and (6) the components of the battery must be
authorized as limited quantities.
Special Provision 401
PHMSA proposes to add a new Special Provision 401, which would
provide instructions on the use of sodium ion battery related proper
shipping names. PHMSA proposes to assign Special Provision 401 to the
following HMT entries:
<bullet> ``UN2795, Batteries, wet, filled with alkali, electric
storage''
<bullet> ``UN3292, Batteries, containing metallic sodium or sodium
alloy''
<bullet> ``UN3292, Cells, containing metallic sodium or sodium alloy''
<bullet> ``UN3551, Sodium ion batteries with organic electrolyte''
<bullet> ``UN3552, Sodium ion batteries contained in equipment with
organic electrolyte''
<bullet> ``UN3552, Sodium ion batteries packed with equipment, with
organic electrolyte''
This same special provision was added to the 23rd edition of the UN
Model Regulations and the 2025-2026 ICAO Technical Instructions
following the addition of new entries for sodium ion batteries. Special
Provision 401 is expected to assist in determining the appropriate
proper shipping name given that there are now six possible shipping
names for batteries that contain different electrolyte chemistries. The
electrolyte chemistry used contributes to the battery and cell hazards,
and therefore different packaging methods and hazard communication are
required. PHMSA does not expect adding this special provision will
impose additional costs, and that it will help shippers to determine
the appropriate provisions applicable to the batteries they are
intending to transport.
Special Provision 402
PHMSA proposes to introduce a new special provision, Special
Provision 402, assigned to ``UN1010, Butadienes and Hydrocarbon
mixture, stabilized containing more than 20 percent butadienes.'' This
special provision would specify required conditions for transport under
this entry, such as a specific vapor pressure which must not exceed 1.1
MPa (11 bar) and a density at 50 [deg]C not lower than 0.525 kg/l at 70
[deg]C. This new special provision adds requirements to increase safety
and ensure stability during transportation of mixtures containing
butadiene. The conditions outlined are in line with the test pressure
and maximum permissible mass contents per liter of capacity for
pressure receptacles and tanks, and are the basis for the markings of
the receptacles and the tanks. PHMSA expects this change to improve
safety and provide clarity and consistency for the description and
classification of butadienes and hydrocarbon mixtures.
Special Provision 406
PHMSA proposes to add a new Special Provision 406 assigned to
``UN1006, Argon,'' ``UN1013, Carbon dioxide,'' ``UN1046, Helium,'' and
``UN1066, Nitrogen.'' This special provision would allow these
materials to be transported, except by air, in the appropriate
authorized DOT specification cylinders and UN pressure receptacles as a
limited quantity material in quantities not more than 1.0 L (34 fluid
ounces) per package. The packagings are further restricted by a maximum
test pressure-capacity product not to exceed 152 bar liter (78
psig[middot]ft\3\)--i.e., the product of the size (capacity) of the
packaging multiplied by the test pressure, cannot exceed 152 bar
liters. The Division 2.2 gases assigned to this special provision would
not be allowed to be packed together (in the same package) with other
hazardous materials.
This proposed amendment would harmonize the HMR with the 23rd
revised edition of the UN Model Regulations, which includes this
special provision (i.e., 406) for limited quantity transport of these
four Division 2.2 non-flammable, non-poisonous compressed gases. Prior
to the addition of this special provision to the UN Model Regulations,
to be transported as a limited quantity, these gases were limited to
quantities not exceeding 120 ml (about four fluid ounces) per inner
packaging. The HMR currently includes this limited quantity provision
for compressed gases--that are not defined as aerosols--in Sec.
173.306(a)(1). The change to the UN Model Regulations was based on and
supported by past experience of safe shipments of these gases in
accordance with regulations adopted by European countries (i.e., ADR)
in volumes exceeding 120 ml and the implementation of special permits
with similar provisions issued by PHMSA.\28\ The rationale behind
limited quantity provisions, which provide exceptions for certain
hazardous materials, is that when appropriately packed in lesser
quantities, these materials pose a lower risk in transport than the
same hazardous materials packed in larger quantities. As a result of
that reduced risk, they are afforded some relief from general
transportation requirements such as hazard labels. When transported as
a limited quantity in accordance with proposed Special Provision 406,
these hazardous
[[Page 6017]]
materials would be excepted from labeling, placarding, and shipping
papers. The DGP determined that the special provision as adopted in the
UN Model Regulations would not be of any substantial value for adoption
for air transportation under the ICAO Technical Instructions because,
though allowed to be transported in greater quantities as limited
quantity material, they would still be subject to marking, labeling,
and shipping papers. PHMSA agrees and proposes to exclude the use of
this new special provision for air transport specifically. In addition,
PHMSA intends to clarify that this provision does not provide shippers
with an alternative classification for cylinders intended to be used as
fire extinguishers that would otherwise be described and classified as
``UN1044, Fire extinguishers.''
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\28\ DOT-SP 20796 and DOT-SP 20936. UNECE, Committee of Experts
on the Transport of Dangerous Goods and on the Globally Harmonized
System of Classification and Labelling of Chemicals--ST/SG/AC.10/
C.3/2022/26 Increase of the limited quantity volume for Division 2.2
compress gases (June 27-July 6, 2022), available at: <a href="https://unece.org/sites/default/files/2022-04/ST-SG-AC.10-C.3-2022-26e.pdf">https://unece.org/sites/default/files/2022-04/ST-SG-AC.10-C.3-2022-26e.pdf</a>.
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This proposed amendment would also respond to a petition for
rulemaking, P-1974, submitted by Hazmat Safety Consulting.\29\ PHMSA
expects that this proposed amendment will facilitate the transport of
important commercial goods that include small cylinders of inert gases.
In addition, PHMSA expects that this change will allow domestic sellers
to capture economies of scale by offering consumers compressed gas
products in larger size options without additional regulatory burden.
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\29\ <a href="http://Regulations.gov">Regulations.gov</a>, PHMSA-2024-0204-P-1794, <a href="https://www.regulations.gov/docket/PHMSA-2024-0204/document">https://www.regulations.gov/docket/PHMSA-2024-0204/document</a>.
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Special Provision 408
PHMSA proposes to add a new Special Provision 408 assigned to
proposed revised ``UN1835 Tetramethylammonium hydroxide aqueous
solution,'' PG II and III, and new ``UN3560, Tetramethylammonium
hydroxide aqueous solution.'' The special provision would limit the use
of these amended HMT entries to only aqueous solutions made of water,
TMAH, and no more than one percent of other constituents. The special
provision would also provide instruction that for other formulations
containing TMAH, the material must be described using an alternative
appropriate generic or n.o.s. HMT entry, except that formulations
containing (1) a surfactant in concentration less than one percent and
with not less than 8.75 percent TMAH must be described using ``UN2927,
Toxic liquids, corrosive, organic, n.o.s., 6.1, PG I;'' or (2)
containing a surfactant in concentration less than one percent and with
more than 2.38 percent but less than 8.75 percent TMAH must be
described using ``UN2927, Toxic liquids, corrosive, organic, n.o.s.,
6.1, PG II.'' PHMSA expects that Special Provision 408 will increase
safety by providing clearer instructions for appropriate selection of
HMT for solutions containing TMAH, which will ensure the hazards of the
material are properly communicated, and appropriate authorized
packaging and modal transport requirements are maintained.
Special Provision 409
PHMSA proposes to add a new Special Provision 409 assigned to
proposed revised ``UN1835 Tetramethylammonium hydroxide aqueous
solution,'' PG II and III; revised ``UN3423, Tetramethylammonium
hydroxide, solid;'' and new ``UN3560, Tetramethylammonium hydroxide
aqueous solution.'' Special Provision 409 would allow shipments of TMAH
materials to continue to be transported in accordance with the HMR
requirements prior to the publication of a final rule until December
31, 2026. This special provision provides a delayed compliance date
that would allow time for shippers and carriers to adjust to the
revisions made to the TMAH HMT entries and associated requirements.
Special Provision A54
Special Provision A54 states that, notwithstanding the quantity
limits in column (9B) of the HMT, lithium batteries (including those
packed with, or contained in, equipment) may exceed a mass of 35 kg (77
lbs.) on cargo aircraft if they otherwise meet the requirements of
Sec. 173.185 and the Associate Administrator provides an approval
prior to shipment.
At the 29th meeting of the ICAO DGP, the DGP adopted revisions to
Special Provision A99 in the 2025-2026 ICAO Technical Instructions,
which has the same requirements as Special Provision A54 in the HMR.
These revisions applied the special provision to the new entries for
sodium ion batteries. This is consistent with other provisions being
adopted that regulate sodium ion batteries in much the same manner as
lithium batteries based on their similar applications and similar
hazards present during transportation. To make this special provision
applicable to sodium ion batteries, PHMSA proposes to amend the special
provision to reference both sodium ion batteries and lithium batteries.
In addition, PHMSA proposes to assign Special Provision A54 to the
following new entries: ``UN3551, Sodium ion batteries with organic
electrolyte,'' ``UN3552, Sodium ion batteries contained in equipment
with organic electrolyte,'' and ``UN3552, Sodium ion batteries packed
with equipment, with organic electrolyte.'' This revision will
harmonize the HMR with the UN Model Regulations and the adoption of
provisions for sodium ion batteries.
Special Provision A100
Special Provision A100 is assigned to ``UN3480, Lithium ion
batteries'' and prescribes state-of-charge requirements. Currently,
this special provision states that lithium ion cells and batteries
transported by air must be offered for transport at a state-of-charge
not exceeding 30 percent of their rated capacity. In addition, lithium
ion cells and batteries at a state-of-charge greater than 30 percent of
their rated capacity may only be transported under conditions as
approved by the Associate Administrator. PHMSA proposes to extend
applicability of this state-of-charge requirement by assigning this
special provision to additional lithium ion battery entries on the HMT
and to revise this special provision to clarify its applicability. In
addition, PHMSA proposes to apply this provision to new HMT entries for
sodium ion batteries and vehicles powered by batteries. These changes
are consistent with revisions in the 2025-2026 ICAO Technical
Instructions.
Specifically, PHMSA proposes to assign Special Provision A100 to
the following entries:
<bullet> ``UN3481, Lithium ion batteries contained in equipment
including lithium ion polymer batteries''
<bullet> ``UN3481, Lithium ion batteries packed with equipment
including lithium ion polymer batteries''
<bullet> ``UN3551, Sodium ion batteries with organic electrolyte''
<bullet> ``UN3552, Sodium ion batteries contained in equipment with
organic electrolyte''
<bullet> ``UN3552, Sodium ion batteries packed with equipment, with
organic electrolyte''
<bullet> ``UN3556, Vehicle, lithium ion battery powered''
<bullet> ``UN3557, Vehicle, lithium metal battery powered''
<bullet> ``UN3558, Vehicle, sodium ion battery powered''
At the 29th meeting of the ICAO DGP, an amendment was considered
that would, under certain conditions, extend the existing provision in
A100 to lithium ion batteries packed with, or contained in, equipment
(UN3481); vehicles powered by lithium ion, lithium metal, or sodium ion
batteries; and sodium ion batteries and sodium ion batteries packed
with, or contained in, equipment. The DGP Working Group
[[Page 6018]]
on Energy Storage Devices arrived at this decision based on an
assessment and safety risk analysis focused on preventing losses due to
incidents involving lithium batteries. The DGP Working Group observed
during data collection that between 2017 and 2023 there was a decline
in transportation incidents involving ``UN3480, Lithium ion
batteries.'' The DGP Working Group hypothesized that the reduction in
incidents was due to both the ban on lithium ion batteries on passenger
aircraft and the requirement for lithium ion batteries to be offered
for transport at a 30 percent state-of-charge on cargo aircraft. The
DGP Working Group stated that incidents involving lithium ion batteries
contained in and packed with equipment hit a low in 2020-2021 but have
since risen. Data also indicated that the number of shipments of
lithium ion batteries contained in and packed with equipment almost
doubled between 2015 and 2022. The DGP's stated goal was to consider
whether risks associated with the air transport of lithium ion
batteries packed with equipment and contained in equipment were
adequately mitigated in consideration of all available information.
The DGP concluded that the risks associated with lithium ion
batteries packed with equipment meeting the requirements of the
applicable ICAO Technical Instruction packing instructions were not
adequately mitigated because, outside of the transportation
requirements for small batteries, there were no limits on the energy
capacity of the batteries. Testing showed, however, that lithium cells
and batteries up to 2.7 Watt-hour (Wh) posed a negligible hazard. Note
that the same is true for the requirements of the HMR when shipping
lithium ion batteries packed with equipment by air; currently, there
are no limits on the Wh rating for lithium cells and batteries not
covered by Sec. 173.185(c) exceptions for smaller lithium cells and
batteries. Therefore, the DGP added a specific condition that for
transport of lithium ion batteries packed with equipment--batteries
that exceed 2.7 Wh must not exceed a state-of-charge of 30 percent of
their rated capacity, while it is only recommended that batteries not
exceeding 2.7 Wh be shipped at a 30 percent state-of-charge. PHMSA
proposes the same conditional requirements and recommendation in
Special Provision A100. By including lithium ion batteries packed with
equipment in Special Provision A100, the risks associated with
transporting lithium ion batteries are further mitigated by limiting
the energy in these batteries.
For lithium ion batteries contained in equipment, the DGP adopted a
recommendation, rather than a requirement, that the lithium ion
batteries be shipped at a 30 percent state-of-charge or should be
offered for transport at an indicated battery capacity not exceeding 25
percent for several reasons. First, the DGP assumed that lithium ion
batteries contained in equipment posed a lesser risk than lithium ion
batteries packed with equipment because of the protection the equipment
itself provides to the batteries and the assumed smaller energy
densities of the lithium batteries. The DGP did not consider the data
presented to be relevant or sufficient to justify a requirement.
Second, the panel did not consider the risk high enough to warrant
mandating something that would significantly impact industry and impede
the shipment by air of certain equipment that needed to be shipped
fully charged, including life-saving medical devices, large information
technology equipment with embedded lithium ion batteries, and military
equipment. Lastly, the panel did not consider the presented data to be
relevant or sufficient to justify a requirement because incidents were
largely due to non-compliant shipments. PHMSA has reviewed the analysis
and agrees with the DGP's conclusions and amendments. Further, PHMSA
believes that including the reduced state-of-charge as a recommendation
for lithium ion batteries contained in equipment is expected to improve
safety by letting shippers know that there is a safety benefit from a
reduced risk of thermal runaway at lower states of charge.
For sodium ion batteries, the DGP deemed that the same requirements
that apply to lithium ion batteries were appropriate for sodium ion
batteries based on the similar risks that the two battery chemistries
share. For further discussion on their similarities, see the Section-
by-Section in Section 172.101. Consistent with the 2025-2026 ICAO
Technical Instructions, PHMSA proposes to extend the 30 percent state-
of-charge requirements to sodium ion batteries, similar to the current
requirements for lithium ion batteries. However, the ICAO DGP did not
adopt this requirement for sodium ion batteries packed with or
contained in equipment. Consistent with the 2025-2026 ICAO Technical
Instructions, PHMSA is not proposing to adopt the 30 percent state-of-
charge requirement for sodium ion batteries packed with, or contained
in, equipment, respectively.
PHMSA also proposes to expand this special provision to state
clearly that the 30 percent state-of-charge requirement also applies to
low production runs and prototypes of lithium ion batteries. This would
harmonize the HMR with Special Provision A88 of the 2025-2026 ICAO
Technical Instructions. In addition, PHMSA proposes to extend the
state-of-charge requirement for low production runs and prototypes to
sodium ion batteries, including those transported packed with or
contained in equipment, and lithium ion batteries packed with and
contained in equipment. This clarification and expansion harmonize the
HMR with the 2025-2026 ICAO Technical Instructions.
PHMSA proposes to harmonize further with the ICAO Technical
Instructions by extending the 30 percent state-of-charge requirement to
sodium ion and lithium ion batteries contained and packed in equipment.
PHMSA proposes to state clearly that the 30 percent state-of-charge
requirement also applies to lithium ion and sodium batteries, including
those packed with and contained in equipment, that are above 35 kg and
transported in accordance with Special Provision A54. While not
explicitly stated, these large lithium ion batteries have been subject
to the state-of-charge requirements, but PHMSA expects this proposed
language to improve clarity.
For vehicles powered by lithium ion batteries, lithium metal
batteries, and sodium ion batteries, the DGP adopted a state-of-charge
requirement for batteries exceeding 100 Wh to be offered for transport
at a state-of-charge not exceeding 30 percent of their rated capacity
or an indicated battery capacity not exceeding 25 percent, and a
recommendation for batteries not exceeding 100 Wh to be offered at a
state-of-charge not exceeding 30 percent of their rated capacity or an
indicated battery capacity not exceeding 25 percent. These limitations
were adopted based on there being no limits on the energy capacity of
the batteries in the vehicles and the likelihood that a thermal runaway
of one of these batteries would have extreme consequences if offered
for transport at a full state-of-charge. The DGP decided that a 25
percent driving range would allow for the movement of the vehicle under
its own power during loading and unloading, and that 25 percent battery
capacity on the vehicle's fuel gauge was considered equivalent to a 30
to 35 percent state-of-charge of the battery based on input from large
automobile manufacturers. The reason that the adopted language in the
ICAO Technical Instruction differs for vehicles powered
[[Page 6019]]
by larger batteries (i.e., must) versus the vehicles powered by smaller
batteries (i.e., should) is that the DGP determined that smaller
vehicle batteries pose less risk based on their Wh rating. The DGP
further supported making a reduced state-of-charge requirement for
larger batteries contained in vehicles, but not for batteries contained
in equipment, because there is no limit on the mass of the batteries in
vehicles, while there was a limit (i.e., 35 kg) for those contained in
equipment.
PHMSA proposes to add text to the end of the special provision to
instruct shippers on where they can find information to determine rated
capacity to accurately determining the state-of-charge. While this text
has been in previous iterations of the ICAO Technical Instructions,
PHMSA believes that the addition provides clarity with the number of
entries that this special provision now applies. This additional text
also reinforces the importance and safety rationale for why these
state-of-charge requirements are necessary.
IBC Special Provision--IP8
IP Codes are special provisions provided for in Table 2 of Sec.
172.102(c)(4) and specify requirements pertaining to the use of IBCs
for the transport of specific commodities listed in the HMT. PHMSA
proposes to amend the text of IP Code, IP8, which is assigned to
``UN2672, Ammonia solution, relative density between 0.880 and 0.957 at
15 degrees C in water, with more than 10 percent but not more than 35
percent ammonia.'' Currently, IP8 states that ammonia solutions may be
transported in rigid or composite plastic IBCs (31H1, 31H2, and 31HZ1)
that have successfully passed, without leakage or permanent
deformation, the hydrostatic test specified in Sec. 178.814 at a test
pressure that is not less than 1.5 times the vapor pressure of the
contents at 55 [deg]C (131 [deg]F). PHMSA proposes to amend the
language in IP8 to reference an IB code, IB3, which will both reiterate
and expand on the authorized IBC types. This expansion will allow for a
wider range of packaging types to be used in the transport of ammonia
solutions, such as new metal IBCs that have been proven to pass the
required tests. This change to IP8 was adopted in the 23rd revised
edition of the UN Model Regulations to allow for the expanded use of
different IBC types, such as metal IBCs that are currently used for
higher concentrations of ammonia solutions. PHMSA expects that this
amendment will facilitate the transport of this material without
sacrificing safety standards by clarifying that, as long as the
required safety tests for the IBCs are passed, UN2672 material can be
transported in a wider variety of IBC types.
PHMSA proposes to correct a publishing error that occurred in an
earlier rulemaking, HM-215Q. In that rulemaking, PHMSA added two new IP
codes (IP15 and IP22) to Table 2. Due to a publishing error, code IP16
was inadvertently deleted, and the corresponding requirements of the
new codes were printed in the wrong column. PHMSA proposes to add IP16
again and correct the formatting in rows IP15 and IP22. IP16 requires
an approval from the Associate Administrator for the use of 31A and 31N
IBCs for materials that are assigned this IP code on the HMT (i.e.,
``UN3375, Ammonium nitrate emulsion or Ammonium nitrate suspension or
Ammonium nitrate gel, intermediate for blasting explosives''). PHMSA
expects that this correction will improve safety by ensuring that
shippers do not transport these materials in 31A or 31N without PHMSA's
oversight.
Portable Tank Special Provision--TP42
TP codes are special provisions that specify requirements
pertaining to the use of IM and UN specification portable tanks for the
transport of specific commodities listed in column (7) of the HMT.
PHMSA proposes to add a new special provision, TP42, assigned to
``UN3482 Alkali metal dispersions, flammable or Alkaline earth metal
dispersions, flammable,'' and to ``UN1391, Alkali metal dispersions or
Alkaline earth metal dispersions,'' for portable tanks. TP42 would
specify that portable tanks are not authorized for metal dispersions
comprised of cesium or rubidium. Technological innovations have allowed
for alkali metals incorporated in liquid dispersions to be incorporated
seamlessly into manufacturing processes and directly printed onto
lithium battery anodes, leading to the increased use of such materials
being transported as ``UN3482, Alkali metal dispersions, flammable or
Alkaline earth metal dispersions, flammable'' or ``UN1391, Alkali metal
dispersions or Alkaline earth metal dispersions.'' Like cesium and
rubidium in their pure forms, metal dispersions containing these
materials are not appropriate for transport in portable tanks because
they do not do enough to mitigate associated risks, such as exposure to
air. Therefore, this change would clarify that not all alkali metals in
dispersions are authorized for transport in UN portable tanks. PHMSA
expects that this amendment will facilitate the safe transportation of
materials that are essential to supporting the use of additional energy
technologies while avoiding the inclusion of cesium and rubidium
dispersions.
Section 172.203
Section 172.203 details additional description requirements that
must be placed on shipping papers for certain shipments of hazardous
materials. Paragraph (d) provides instructions for the description of
Class 7 (radioactive) materials. Consistent with provisions adopted in
the 2025-2026 ICAO Technical Instructions, PHMSA proposes to require
that shipping papers for certain packages containing radioactive
material include the dimensions of those packages when transported by
air. Currently, when packages are required to bear the ``RADIOACTIVE
YELLOW-II'' or ``RADIOACTIVE YELLOW-III'' labels, shippers are only
required to indicate the transport index assigned to each package as a
part of the shipping description. This amendment would further require
that when a package bears a ``RADIOACTIVE YELLOW-II'' or ``RADIOACTIVE
YELLOW-III'' label, the dimensions (including dimensional units of the
package, or, when placed in an overpack or freight container, the
dimensions of the overpack or freight container, as applicable) be
indicated on the shipping paper. Specifically, the dimensions should be
shown in the following order: length then width (or diameter, if
applicable). The dimensions may be followed by the letters ``L,'' ``W''
(or ``D''), and ``H'' when listed in this order. Further, if dimensions
are listed in an order other than ``length by width (or diameter) by
height,'' then the letters ``L'', ``W'' (or ``D''), and ``H'' must be
listed in association with the individual measurement (e.g., 10'' (H) x
7'' (W) x 12'' (L)).
The DGP adopted this requirement to facilitate loading procedures
by ensuring that the required minimum distance from the surface of a
package to the nearest surface of a passenger cabin, flight deck
partition, or floors is maintained, as specified in Sec. Sec. 175.701
and 175.702. The DGP also agreed on these changes, in part, because
operators and associations of large aircrafts have already required
this information on dangerous goods transport documents for many years.
PHMSA expects that standardizing the format in which the dimensions of
packages overpacks and freight containers are recorded on shipping
papers will enhance safety and benefit operators by making necessary
information easier to identify and helping streamline preloading
activities.
[[Page 6020]]
Section 172.315
Section 172.315 outlines the marking requirements for limited
quantities. PHMSA proposes to amend Sec. 172.315 by removing two
obsolete transitional exceptions in Sec. 172.315 that permitted the
use of older limited quantity marking specifications for size and shape
until December 31, 2016. PHMSA expects that removing these paragraphs
from the HMR will improve consistency and clarity and prevent
misunderstanding by eliminating potentially misleading information.
Section 172.322
Section 172.322 outlines the marking requirements for marine
pollutants. PHMSA proposes to amend Sec. 172.322 by removing an
obsolete transitional exception in paragraph (e)(3) that permitted the
use of older marine pollutant marking specifications for size and shape
until December 31, 2016. PHMSA expects that removing this paragraph
will improve consistency and clarity within the regulations and prevent
misunderstanding of this section by eliminating potentially misleading
information.
Section 172.447
Section 172.447 prescribes specifications for lithium batteries
labels for shipping. To accommodate the new HMT entries for sodium ion
batteries and the adoption of provisions similar to lithium batteries,
PHMSA proposes to rename this label the ``LITHIUM BATTERY or SODIUM ION
BATTERY'' label. This is consistent with the adoption of sodium ion
battery regulations in the 23rd revised edition of the UN Model
Regulations and 2025-2026 ICAO Technical Instructions. PHMSA expects
that amending this section to identify the label as ``LITHIUM BATTERY
or SODIUM ION BATTERY'' will ensure that shippers are aware of proper
hazard communication for the new entries for sodium ion batteries and
that the hazards associated with those batteries are clearly
communicated during transportation.
Part 173
Section 173.14
Section 173.14 provides exceptions from the HMR for certain devices
or equipment, such as data loggers and cargo tracking devices,
containing hazardous materials that are in use, or which are intended
for use, during transport. These devices or equipment are often powered
by hazardous materials, such as lithium batteries or cells. PHMSA added
this section in a prior rulemaking, HM-215P, but only provided limited
exceptions for data loggers and cargo tracking devices when transported
by air, which only applied to packages equipped with data loggers that
contained COVID-19 pharmaceuticals to allow for additional time to
gather safety data involving these devices.\30\
---------------------------------------------------------------------------
\30\ 87 FR 44944 (Jul. 26, 2022).
---------------------------------------------------------------------------
In the 2025-2026 ICAO Technical Instructions, the DGP adopted more
expansive provisions for these items. The DGP added an allowance for
the transport of data loggers and cargo tracking devices with installed
lithium batteries, attached to, or placed in packages, overpacks, or
unit load devices on aircraft, under certain provisions. These new
provisions address earlier concerns related to the hazards posed by
lithium batteries in air transport, specifically related to the energy
capacity of the lithium batteries that power these items. In addition,
the DGP reviewed requirements developed during a prior working group
and engaged with industry to gain an understanding of the size of cells
and batteries being used in data loggers and cargo tracking devices, as
well as what new technologies may emerge with lithium batteries. The
DGP considered the information and adopted limits to the provisions
under which the exception would apply including: the data logger or
cargo tracking device must be in use or intended for use during
transport; the lithium battery must meet UN 38.3 testing; test summary
requirements; and quality management program requirements (note, this
is not a current HMR requirement) similar to the requirements of
Special Provision 388. In addition, a maximum lithium content of one
gram for a lithium metal cell or battery and a maximum Watt-hour rating
of 20 Wh for lithium ion cell or battery; a limit on the number of data
loggers or cargo tracking devices per package; a requirement that these
devices be capable of withstanding the shocks and loadings normally
encountered during transport; a requirement that the devices must not
be capable of generating a dangerous evolution of heat; and a
requirement that the devices meet defined standards for electromagnetic
radiation to ensure the operation of the device does not interfere with
aircraft systems.
PHMSA agrees with the DGP's findings and proposes to adopt these
exceptions for data loggers and cargo tracking devices for items
transported by air. However, the DGP did not remove the previously
added exceptions from marking and documentation applicable to shipments
of packages containing COVID-19 pharmaceuticals from the 2025-2026 ICAO
Technical Instructions. PHMSA seeks comment on whether to retain this
provision in the HMR. PHMSA also proposes to rearrange this section by
adding this proposed exception in paragraph (b) and moving the
provisions for packages containing COVID-19 pharmaceuticals to a new
paragraph (c) along with similar provisions to use the exception.
PHMSA expects that these changes will facilitate the transport of
hazardous materials and other important goods by air without
compromising safety. PHMSA notes that proposed paragraph (b) only
provides an exception from the HMR and does not provide an exception
for data loggers or cargo tracking devices from complying with other
requirements, such as any applicable FAA regulations, FAA Orders,
operator requirements, and ULD manufacturer requirements. This
amendment will allow shippers and carriers of goods by air to monitor
and record environmental conditions for product quality and to monitor
product location without compromising safety of air transportation.
PHMSA expects the additional costs shippers may incur to take advantage
of this expanded regulatory relief to be minimal.
As stated in the HM-215P final rule, PHMSA reiterates that the
intent of Sec. 173.14 is not to capture those hazardous materials
within active equipment being offered for transportation as part of a
consignment (i.e., offered into commerce). For example, this section
does not apply to electronic devices (such as hearing aids that may
always be powered on as part of their design) that are themselves being
offered for transportation as cargo. Rather, these provisions are only
applicable to data loggers and cargo tracking devices that are in use
and installed, attached to, or placed in packages to provide monitoring
and tracking of those packages, or their handling containers, during
transit. PHMSA expects that these changes will facilitate the transport
of hazardous materials and other important goods by air without
compromising safety.
Section 173.59
Section 173.59 provides informational descriptions of terms for
explosives. Consistent with provisions adopted in the 23rd revised
edition UN Model Regulations, PHMSA proposes to add the term
``pyrotechnic substance'' in this section. A pyrotechnic substance is
an explosive substance designed to produce an effect by heat, light,
sound,
[[Page 6021]]
gas, or smoke (or a combination thereof) as the result of non-
detonative self-sustaining exothermic chemical reactions. A pyrotechnic
substance is a subset of explosive substances, and the term is included
in the definition of ``explosive'' in Sec. 173.50(a), which states
that an explosive ``includes a pyrotechnic substance or article, unless
the substance or article is otherwise classed under the provisions of
this subchapter.'' As currently written, the relationship between
explosive substance and pyrotechnic substance is not obvious in the
definition itself, which may result in confusion in the application of
the definition of pyrotechnic substance. While this section already
contains a definition for ``Articles, pyrotechnic for technical
purposes,'' the underlying energetics of these articles are pyrotechnic
substances. PHMSA believes adding the specific definition will add
clarity to the design and properties of a pyrotechnic substance and
prevent confusion in the understanding and application of the term
throughout the HMR.
Section 173.62
Section 173.62 provides specific packaging requirements for
explosives. PHMSA proposes to revise the Explosives Table in Table 1 to
paragraph (b) to add a new entry for fire suppressant dispersing
devices classed as Division 1.4S material, specifically, ``UN0514,''
and assigned Packing Instruction 135, consistent with the new HMT entry
as discussed in the Section 172.101 summary above. This proposed
revision to the table is consistent with the assignment of Packing
Instruction P135 to ``UN0514'' in the 23rd revised edition of the UN
Model Regulations DGL and will provide the specific authorized
packaging (i.e., inner packaging and outer packaging). See Section V.
Sec. 173.169 summary for a detailed discussion of fire suppressant
dispersing devices and proposed requirements for their classification,
handling, and transportation.
In addition, in a prior rulemaking, HM-215P, PHMSA added new
entries to the HMT for ``UN0511, UN0512, and UN0513, Detonators,
electronic programmable for blasting,'' and assigned Sec. 173.62 for
authorized packaging. However, PHMSA did not make corresponding
additions of these entries to Table 1 to paragraph (b) (Explosives
Table), nor to Table 2 to paragraph (c)(5) (Table of Packing Methods)
for Packing Instruction 131, which is assigned to these HMT entries.
Consequently, these HMT entries direct users to authorized packaging in
Sec. 173.62 without specifying the packaging requirements that apply
to UN0511, UN0512, and UN0513. PHMSA proposes to correct this omission
by adding these entries to the table and their corresponding packaging
instruction consistent with the UN Model Regulations. Specifically, in
the Explosives Table in Sec. 173.62(b), PHMSA proposes to add these
three UN numbers and assign them Packing Instruction 131, consistent
with assignment of these packaging requirements for ``Detonators,
electric, for blasting.'' Furthermore, in the Table of Packing Methods,
for Packing Instruction 131, PHMSA proposes to apply the same packaging
requirements that are currently applicable to ``UN0030,'' ``UN0255,''
and ``UN0456'', Detonators, electric, for blasting'' to entries
``UN0511'', ``UN0512,'' and ``UN0513.'' While these detonators pose the
same hazards in transportation, the new entries were added to
distinguish electronic detonators from electric detonators, as they
have significantly different design characteristics and safety features
for end use operators. Because the hazard in transportation is the
same, these entries are assigned the same packaging requirements as
those currently prescribed for ``UN0030,'' ``UN0255,'' ``UN0456.''
PHMSA expects that this correction will better facilitate the
transport of electronic programmable detonators by specifying the
required packaging requirements for these materials.
Section 173.124 and 173.125
Section 173.124 outlines the definitions for Class 4 materials,
which include Division 4.1 (flammable solids), Division 4.2
(spontaneously combustible materials), and Division 4.3 (dangerous when
wet materials). PHMSA proposes to amend the definition of readily
combustible solids in Sec. 173.124(a)(3) by adding language that
explicitly states that the criteria for metal powders is also
applicable to powders of metal alloys.
Currently, paragraph (a)(3)(iii) of this section defines readily
combustible solid materials as ``any metal powders that can be ignited
and react over the whole length of a sample in 10 minutes or less, when
tested in accordance with the UN Manual of Tests and Criteria.''
However, the UN Manual of Test and Criteria includes two different
criteria for flammability--one for ``powdered, granular, or pasty
substances or mixtures,'' and another for ``powders of metal or metal
alloys.'' In addition, as previously written, some paragraphs related
to Test N.1 in the UN Manual of Tests and Criteria and the relevant
classification criteria were applicable only to metal powders, rather
than explicitly stating that they should also apply to metal alloys.
The UNSCOE identified and corrected this conflict in the 23rd revised
edition of the UN Model Regulations by adding text that states that the
criteria for metal powders is also applicable to powders of metal
alloys.
PHMSA agrees with the UNSCOE's assessment that this is an editorial
oversight, given that powders of metal alloys share the same
flammability characteristics as metal powders. Due to the difficulty of
extinguishing a fire involving metal powders, (i.e., normal
extinguishing agents such as carbon dioxide or water can increase the
hazard) special consideration is needed when determining flammability.
Therefore, stating that metal powders are powders of metal or metal
alloys will ensure both metal powders and powders of metal alloys are
appropriately classified using the criteria for metal powders instead
of the criteria for ``other substances or mixtures.''
In addition, in Sec. 173.125, which outlines the criteria for
assigning packing groups to Class 4 materials, PHMSA proposes to amend
paragraphs (b)(1) and (b)(2) to replace the phrase, ``powders of metals
or metal alloys,'' with the term, ``metal powders.'' This change would
provide consistency with the newly added definition of metal powders
provided in Sec. 173.124. PHMSA expects these amendments will enhance
safety by applying the classification criteria for metal powders to
powders of metal alloys as opposed to the criteria for other powdered,
granular, or pasty substances or mixtures.
Section 173.151
Section 173.151 contains exceptions for Class 4 hazardous
materials. In the HM-215Q final rule, PHMSA added ``151'' in column
(8a) of the HMT for ``UN3148, Water-reactive liquid, n.o.s.'' for
authorized transportation exceptions.\31\ PHMSA also revised Sec.
173.151(d) introductory text applying to limited quantities of Division
4.3 (dangerous when wet) material to include both ``solids'' and
``liquids'' to reflect accurately that Division 4.3 materials could be
either in a solid or liquid state. However, when making these changes,
PHMSA inadvertently omitted revisions to paragraphs (d)(1) and (d)(2),
which specify authorized combination packaging to address the addition
of inner packaging quantity limits for ``liquids'' to paragr
[…truncated; see source link]Indexed from Federal Register on February 10, 2026.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.