Notice2026-05288
Request for Public Comment on the Draft Immediately Dangerous to Life or Health (IDLH) Value Document for Lewisite
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
March 18, 2026
Issuing agencies
Health and Human Services DepartmentCenters for Disease Control and Prevention
Abstract
The National Institute for Occupational Safety and Health (NIOSH) in the Centers for Disease Control and Prevention (CDC), an Operating Division of the Department of Health and Human Services (HHS), requests public comment on the draft Immediately Dangerous to Life or Health (IDLH) Value Profile document for the chemical lewisite (CAS# 541-25-3). NIOSH develops IDLH values for workplace chemical concentrations and conditions carrying immediate, unacceptable health risks. IDLH values are based on health effects considerations determined through a critical assessment of toxicology and human health effects data.
Full Text
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<title>Federal Register, Volume 91 Issue 52 (Wednesday, March 18, 2026)</title>
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[Federal Register Volume 91, Number 52 (Wednesday, March 18, 2026)]
[Notices]
[Pages 13027-13028]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-05288]
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DEPARTMENT OF HEALTH AND HUMAN SERVICES
Centers for Disease Control and Prevention
[Docket Number CDC-2019-0093, NIOSH-156-E]
Request for Public Comment on the Draft Immediately Dangerous to
Life or Health (IDLH) Value Document for Lewisite
AGENCY: Centers for Disease Control and Prevention (CDC), Department of
Health and Human Services (HHS).
ACTION: Request for comment.
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SUMMARY: The National Institute for Occupational Safety and Health
(NIOSH) in the Centers for Disease Control and Prevention (CDC), an
Operating Division of the Department of Health and Human Services
(HHS), requests public comment on the draft Immediately Dangerous to
Life or Health (IDLH) Value Profile document for the chemical lewisite
(CAS# 541-25-3). NIOSH develops IDLH values for workplace chemical
concentrations and conditions carrying immediate, unacceptable health
risks. IDLH values are based on health effects considerations
determined through a critical assessment of toxicology and human health
effects data.
DATES: Electronic or written comments must be received by May 18, 2026.
ADDRESSES: You may submit comments, identified by docket number CDC-
2019-0093 and docket number NIOSH-156-E, by either of the following
methods:
<bullet> Federal eRulemaking Portal: <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
Follow the instructions for submitting comments.
<bullet> Mail: National Institute for Occupational Safety and
Health, NIOSH Docket Office, 1090 Tusculum Avenue, MS C-34, Cincinnati,
Ohio 45226-1998.
Instructions: All information received in response to this notice
must include the agency name and docket number (CDC-2019-0093; NIOSH-
156-E). All relevant comments, including any personal information
provided, will be posted without change to <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
Do not submit comments by email. CDC does not accept comments by email.
For access to the docket to read background documents or comments
received, go to <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
FOR FURTHER INFORMATION CONTACT: R. Todd Niemeier, Ph.D., National
Institute for Occupational Safety and Health, MS-C15, 1090 Tusculum
Avenue, Cincinnati, OH 45226. Telephone: (513) 533-8166.
SUPPLEMENTARY INFORMATION: NIOSH is requesting public comment on a
draft IDLH Value Profile document for the chemical lewisite. Lewisite
is an oily substance that actively produces gas in room temperature air
and was developed as a blister agent during World War I. NIOSH
developed the draft IDLH Value Profile document to provide the
scientific rationale behind the derivation of an IDLH value for
lewisite. It provides a detailed summary of the health hazards of acute
exposures to high airborne concentrations of lewisite and the rationale
for the IDLH value. The final publication, which will address public
comments, will be available on the NIOSH website and in the NIOSH
docket 156-E and in <a href="http://Regulations.gov">Regulations.gov</a> CDC-2019-0093.
[[Page 13028]]
To facilitate the review of this document, NIOSH requests comment
on the following specific questions for this draft Profile document:
1. Does this document clearly outline the health hazards associated
with acute (or short-term) exposures to lewisite? If not, what specific
information is missing from the document?
2. Are the rationale and logic behind the derivation of an IDLH
value for lewisite clearly explained? If not, what specific information
is needed to clarify the basis of the IDLH value?
3. Are the conclusions supported by the data?
4. Are the tables clear and appropriate?
5. Is the document organized appropriately? If not, what
improvements are needed?
6. Are you aware of any additional scientific data reported in
government publications, databases, peer-reviewed journals, or other
sources that should be considered in this document?
Background: NIOSH develops IDLH values for workplace chemical
concentrations and conditions carrying immediate, unacceptable health
risks. Since the establishment of the IDLH values in the 1970s, NIOSH
continues to review available scientific data to improve the protocol
used to derive acute exposure guidelines, in addition to the chemical-
specific IDLH values. IDLH values are based on health effects
considerations determined through a critical assessment of toxicology
and human health effects data. This approach ensures that the IDLH
values reflect an airborne concentration of a substance that represents
a high-risk situation that may endanger workers' lives or health.
In 2013, NIOSH published Current Intelligence Bulletin (CIB) 66:
Derivation of Immediately Dangerous to Life or Health (IDLH) Values
[<a href="http://www.cdc.gov/niosh/docs/2014-100/pdfs/2014-100.pdf">http://www.cdc.gov/niosh/docs/2014-100/pdfs/2014-100.pdf</a>] [NIOSH
2013]. The information presented in this CIB represents the most recent
update of the scientific rationale and the methodology (hereby referred
to as the IDLH methodology) used to derive IDLH values. The primary
steps used to establish an IDLH value are the following:
1. Critical review of human and animal toxicity data to identify
potentially relevant studies and characterize the various lines of
evidence that can support the derivation of the IDLH value;
2. Determination of a chemical's mode of action or description of
how a chemical exerts its toxic effects;
3. Application of duration adjustments (time scaling) to determine
30-minute-equivalent exposure concentrations and the conduct of other
dosimetry adjustments, as needed;
4. Experimental or other data to establish a point of departure
(POD) such as lethal concentrations (e.g., LC50), lowest observed
adverse effect level (LOAEL), or no observed adverse effect level
(NOAEL);
5. Selection and application of an uncertainty factor (UF) for POD
or critical adverse effect concentration, identified from the available
studies to account for issues associated with interspecies and
intraspecies differences, severity of the observed effects, data
quality, or data insufficiencies; and
6. Development of the final recommendation for the IDLH value from
the various alternative lines of evidence, with use of a weight-of-
evidence approach to all the data.
Reference
NIOSH [2013]. Current intelligence bulletin 66: derivation of
immediately dangerous to life or health (IDLH) values. Cincinnati,
OH: US Department of Health and Human Services, Centers for Disease
Control and Prevention, National Institute for Occupational Safety
and Health, DHHS (NIOSH) Publication 2014-100.
John J. Howard,
Director, National Institute for Occupational Safety and Health,
Centers for Disease Control and Prevention, Department of Health and
Human Services.
[FR Doc. 2026-05288 Filed 3-17-26; 8:45 am]
BILLING CODE 4163-18-P
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