Notice2025-13885
CBNA/Halmar Joint Venture; Application for Permanent Variance and Interim Order; Grant of Interim Order; Request for Comments
Primary source
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Published
July 24, 2025
Effective
July 24, 2025
Issuing agencies
Labor DepartmentOccupational Safety and Health Administration
Abstract
In this notice, OSHA announces the application of CBNA/Halmar Joint Venture (CBNA) for a permanent variance and interim order from provisions of the OSHA standard that regulates work in compressed-air environments, presents the agency's preliminary finding on CBNA's application, and announces the grant of an interim order. OSHA invites the public to submit comments on the variance application to assist the agency in determining whether to grant the applicant a permanent variance based on the conditions specified in this application.
Full Text
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<title>Federal Register, Volume 90 Issue 140 (Thursday, July 24, 2025)</title>
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[Federal Register Volume 90, Number 140 (Thursday, July 24, 2025)]
[Notices]
[Pages 34902-34911]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-13885]
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DEPARTMENT OF LABOR
Occupational Safety and Health Administration
[Docket No. OSHA-2025-0002]
CBNA/Halmar Joint Venture; Application for Permanent Variance and
Interim Order; Grant of Interim Order; Request for Comments
AGENCY: Occupational Safety and Health Administration (OSHA), Labor.
ACTION: Notice.
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SUMMARY: In this notice, OSHA announces the application of CBNA/Halmar
Joint Venture (CBNA) for a permanent variance and interim order from
provisions of the OSHA standard that regulates work in compressed-air
environments, presents the agency's preliminary finding on CBNA's
application, and announces the grant of an interim order. OSHA invites
the public to submit comments on the variance application to assist the
agency in determining whether to grant the applicant a permanent
variance based on the conditions specified in this application.
DATES: Submit comments, information, documents in response to this
notice, and request for a hearing on or before August 25, 2025. The
interim order described in this notice will become effective on July
24, 2025, and shall remain in effect until the completion of the
Potomac River Tunnel Project in Washington, DC, the interim order is
modified or revoked, or OSHA publishes a decision on the permanent
variance application.
ADDRESSES:
Electronically: You may submit comments, including attachments,
electronically at <a href="http://www.regulations.gov">http://www.regulations.gov</a>, the Federal eRulemaking
Portal. Follow the instructions online for making electronic
submissions.
Instructions: All submissions must include the agency's name and
the docket number for this rulemaking (Docket No. OSHA-2025-0002). All
comments, including any personal information you provide, are placed in
the public docket without change and may be made available online at
<a href="https://www.regulations.gov">https://www.regulations.gov</a>. Therefore, OSHA cautions commenters about
submitting information they do not want made available to the public or
submitting materials that contain personal information (either about
themselves or others), such as Social Security numbers and birthdates.
Docket: To read or download comments or other material in the
docket, go to <a href="http://www.regulations.gov">http://www.regulations.gov</a>. Documents in the docket
(including this Federal Register notice) are listed in the <a href="http://www.regulations.gov">http://www.regulations.gov</a> index; however, some information (e.g., copyrighted
material) is not publicly available to read or download through the
website. All submissions, including copyrighted material, are available
for inspection through the OSHA Docket Office. Contact the OSHA Docket
Office at (202) 693-2350 (TTY (877) 889-5627) for assistance in
locating docket submissions.
Extension of comment period: Submit requests for an extension of
the comment period on or before August 25, 2025 to the Office of
Technical Programs and Coordination Activities, Directorate of
Technical Support and Emergency Management, Occupational Safety and
Health Administration, U.S. Department of Labor, 200 Constitution
Avenue NW, Room N-3653, Washington, DC 20210, or by fax to (202) 693-
1644.
FOR FURTHER INFORMATION CONTACT: Information regarding this notice is
available from the following sources:
Press inquiries: Contact Mr. Frank Meilinger, Director, OSHA Office
of Communications, U.S. Department of Labor; telephone: (202) 693-1999;
email: <a href="/cdn-cgi/l/email-protection#7419111d181d1a1311065a1206151a171d074634101b185a131b02"><span class="__cf_email__" data-cfemail="98f5fdf1f4f1f6fffdeab6feeaf9f6fbf1ebaad8fcf7f4b6fff7ee">[email protected]</span></a>.
General and technical information: Contact Mr. Kevin Robinson,
Director, Office of Technical Programs and Coordination Activities,
Directorate of Technical Support and Emergency Management, Occupational
Safety and Health Administration, U.S. Department of Labor; telephone:
(202) 693-1911; email: <a href="/cdn-cgi/l/email-protection#98eaf7faf1f6ebf7f6b6f3fdeef1f6d8fcf7f4b6fff7ee"><span class="__cf_email__" data-cfemail="196b767b70776a767737727c6f7077597d7675377e766f">[email protected]</span></a>.
Copies of this Federal Register notice. Electronic copies of this
Federal Register notice are available at <a href="http://www.regulations.gov">http://www.regulations.gov</a>.
This Federal Register notice, as well as news releases and other
relevant information, also are available at OSHA's web page at <a href="http://www.osha.gov">http://www.osha.gov</a>.
Hearing Requests. According to 29 CFR 1905.15, hearing requests
must include: (1) a concise statement of facts detailing how the
permanent variance would affect the requesting party; (2) a
specification of any statement or representation in the variance
application that the commenter denies, and a concise summary of the
evidence offered in support of each denial; and (3) any views or
arguments on any issue of fact or law presented in the variance
application.
SUPPLEMENTARY INFORMATION:
I. Notice of Application
On April 1, 2024, CBNA/Halmar Joint Venture (CBNA or the
applicant), submitted under Section 6(d) of the Occupational Safety and
Health Act of 1970 (the Act), 29 U.S.C. 655, and 29 CFR 1905.11
(variances and other relief under Section 6(d)) an application for a
permanent variance from several provisions of the OSHA standard that
regulates work in compressed air, 1926.803 of 1926 Subpart S--
Underground Construction, Caissons, Cofferdams, and Compressed Air, and
an interim order allowing it to proceed while OSHA considers the
request for a permanent variance (OSHA-2025-0002-0002). This notice
addresses CBNA's application for a permanent variance and interim order
for construction of the Potomac River Tunnel Project in Washington, DC
only and is not applicable to future CBNA tunneling projects.
Specifically, this notice addresses CBNA's application for a
permanent variance and interim order from the provisions of the
standard that: (1) require the use of the decompression values
specified in decompression tables in Appendix A of subpart S (29 CFR
1926.803(f)(1)); and (2) require the use of automated operational
controls and a special decompression chamber (29 CFR
1926.803(g)(1)(iii) and (xvii), respectively).
OSHA has previously approved nearly identical provisions when
granting several other very similar variances, as discussed in more
detail in Section II. OSHA preliminarily concludes that the proposed
variance is appropriate, grants an interim order temporarily allowing
the proposed activity, and seeks comment on the proposed variance.
A. Background
The applicant is a contractor that works on complex tunnel projects
using innovations in tunnel-excavation methods. The applicant's workers
engage in the construction of tunnels using advanced shielded
mechanical excavation techniques in conjunction with an earth pressure
balanced micro-tunnel boring machine (TBM). Using shielded mechanical
excavation techniques, in conjunction with precast concrete tunnel
liners and backfill grout, TBMs provide methods to achieve
[[Page 34903]]
the face pressures required to maintain a stabilized tunnel face
through various geologies and isolate that pressure to the forward
section (the excavation working chamber) of the TBM.
CBNA asserts that it bores tunnels using a TBM at levels below the
water table through soft soils consisting of clay, silt and sand. TBMs
are capable of maintaining pressure at the tunnel face and stabilizing
existing geological conditions through the controlled use of a
mechanically driven cutter head, bulkheads within the shield, ground-
treatment foam, and a screw conveyor that moves excavated material from
the working chamber. The forward-most portion of the TBM is the working
chamber, and this chamber is the only pressurized segment of the TBM.
Within the shield, the working chamber consists of two sections: the
forward working chamber and the staging chamber. The forward working
chamber is immediately behind the cutter head and tunnel face. The
staging chamber is behind the forward working chamber and between the
man-lock door and the entry door to the forward working chamber.
The TBM has twin man-locks located between the pressurized working
chamber and the non-pressurized portion of the machine. Each man-lock
has two compartments. This configuration allows workers to access the
man-locks for compression and decompression, and medical personnel to
access the man-locks if required in an emergency.
CBNA's Hyperbaric Operations Manual (HOM) for the Potomac River
Tunnel Project (OSHA-2025-0002-0003) indicates that the maximum
pressure to which it is likely to expose workers during project
interventions for the tunnel drives associated with the Potomac River
Tunnel Project is 49.5 per square inch gauge (p.s.i.g). The applicant
will pressurize the working chamber to the level required to maintain a
stable tunnel face, which for this project CBNA estimates will be up to
a pressure not exceeding 49.5 p.s.i.g., which does not exceed the
maximum pressure specified by the OSHA standard at 29 CFR
1926.803(e)(5).\1\ CBNA is not seeking a variance from this provision
of the compressed-air standard.
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\1\ The decompression tables in Appendix A of subpart S express
the working pressures as pounds per square inch gauge (p.s.i.g.).
Therefore, throughout this notice, OSHA expresses the p.s.i. value
specified by 29 CFR 1926.803(e)(5) as p.s.i.g., consistent with the
terminology in Appendix A, Table 1 of subpart S.
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CBNA employs specially trained personnel for the construction of
the tunnel. To keep the machinery working effectively, CBNA asserts
that these workers must periodically enter the excavation working
chamber of the TBM to perform hyperbaric interventions during which
workers would be exposed to air pressures up to 49.5 p.s.i.g., These
interventions consist of conducting inspections or maintenance work on
the cutter-head structure and cutting tools of the TBM, such as
changing replaceable cutting tools and disposable wear bars, and, in
rare cases, repairing structural damage to the cutter head. These
interventions are the only time that workers are exposed to compressed
air. Interventions in the working chamber (the pressurized portion of
the TBM) take place only after halting tunnel excavation and preparing
the machine and crew for an intervention.
During interventions, workers enter the working chamber through one
of the twin man-locks that open into the staging chamber. To reach the
forward part of the working chamber, workers pass through a door in a
bulkhead that separates the staging chamber from the forward working
chamber. The man-locks and the working chamber are designed to
accommodate three people, which is the maximum crew size allowed under
the proposed variance. When the required decompression times are
greater than work times, the twin man-locks allow for crew rotation.
During crew rotation, one crew can be compressing or decompressing
while the second crew is working. Therefore, the working crew always
has an unoccupied man-lock at its disposal.
CBNA asserts that these innovations in tunnel excavation have
greatly reduced worker exposure to hazards of pressurized air work
because they have eliminated the need to pressurize the entire tunnel
for the project and would thereby reduce the number of workers exposed,
as well as the total duration of exposure, to hyperbaric pressure
during tunnel construction. These advances in technology substantially
modified the methods used by the construction industry to excavate
subaqueous tunnels compared to caisson work.
In addition to the reduced exposures resulting from the innovations
in tunnel-excavation methods, CBNA asserts that innovations in
hyperbaric medicine and technology improve the safety of decompression
from hyperbaric exposures. These procedures, however, would deviate
from the decompression process that OSHA requires for construction in
29 CFR 1926.803(f)(1) and the decompression tables in Appendix A of 29
CFR 1926, subpart S. Nevertheless, according to CBNA, their use of
decompression protocols incorporating oxygen is more efficient,
effective, and safer for tunnel workers than compliance with the
decompression tables specified by the existing OSHA standard.
CBNA therefore believes its workers will be at least as safe under
its proposed alternatives as they would be under OSHA's standard
because of the reduction in number of workers and duration of
hyperbaric exposures, better application of hyperbaric medicine, and
the development of a project-specific HOM that requires specialized
medical support and hyperbaric supervision to provide assistance to a
team of specially trained man-lock attendants and hyperbaric or
compressed-air workers (CAWs).
Based on an initial review of CBNA's application for a permanent
variance and interim order for the construction of the Potomac River
Tunnel Project in Washington, DC, OSHA has preliminarily determined
that CBNA has proposed an alternative that would provide a workplace at
least as safe and healthful as that provided by the standard.
II. The Variance Application
Pursuant to the requirements of OSHA's variance regulations (29 CFR
part 1905), the applicant has certified that it notified its workers
\2\ of the variance modification application and request for interim
order by posting, at prominent locations where it normally posts
workplace notices, a summary of the application and information
specifying where the workers can examine a copy of the application. In
addition, the applicant informed its workers and their representatives
of their rights to petition the Assistant Secretary for Occupational
Safety and Health for a hearing on the variance application.
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\2\ See the definition of ``Affected employee or worker'' in
section V.D of this notice.
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A. OSHA History of Approval of Nearly Identical Variance Requests
OSHA has previously approved several nearly identical variances
involving the same types of tunneling equipment used for similar
projects. OSHA notes that it granted several subaqueous tunnel
construction permanent variances from the same provisions of OSHA's
compressed-air standard (29 CFR 1926.803(e)(5), (f)(1), (g)(1)(iii),
and (g)(1)(xvii)) that are the subject of the present application: (1)
Impregilo Healy Parsons Joint Venture (IHP JV) for the Anacostia River
Tunnel
[[Page 34904]]
in Washington, DC (80 FR 50652, August 20, 2015); (2) Traylor JV for
the Blue Plains Tunnel in Washington, DC (80 FR 16440, March 27, 2015);
(3) Tully/OHL USA JV for the New York Economic Development
Corporation's New York Siphon Tunnel project (79 FR 29809, May 23,
2014); (4) Salini-Impregilo/Healy JV for the Northeast Boundary Tunnel
in Washington, DC (85 FR 27767, May 11, 2020); (5) McNally/Kiewit SST
for the Shoreline Storage Tunnel in Cleveland, Ohio (88 FR 15080, March
10, 2023); (6) Traylor Shea JV for the Alexandria RiverRenew Tunnel
Project in Alexandria, Virginia and Washington, DC (88 FR 15090, March
10, 2023); (7) Traylor-Sundt Joint Venture, for the Integrated Pipeline
Tunnel Project in Dallas, Texas (88 FR 83152, November 28, 2023); (8)
Ballard Marine Construction for the Bay Park Conveyance Tunnel Project
in Nassau County, New York (89 FR 8442, February 7, 2024); and (9)
Ballard Marine Construction for the Lower Olentangy Tunnel Project in
Columbus, Ohio (89 FR 78906, September 26, 2024). OSHA also granted an
interim order to Ballard Marine Construction for the Suffolk County,
New York Outfall Tunnel Project (86 FR 5253, January 19, 2021). The
proposed alternate conditions in this notice are nearly identical to
the alternate conditions of the previous permanent variances and the
interim order.\3\ OSHA is not aware of any injuries or other safety
issues that arose from work performed under these conditions in
accordance with the previous variances.
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\3\ Most of the other subaqueous tunnel construction variances
allowed further deviation from OSHA standards by permitting employee
exposures above 50 p.s.i.g. based on the composition of the soil and
the amount of water above the tunnel for various sections of those
projects. The current proposed variance includes substantively the
same safeguards as the variances that OSHA granted previously, even
though employees will only be exposed to pressures up to 49.5
p.s.i.g.
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B. Variance From Paragraph (f)(1) of 29 CFR 1926.803, Requirement To
Use OSHA Decompression Tables
OSHA's compressed-air standard for construction requires
decompression in accordance with the decompression tables in Appendix A
of 29 CFR 1926, subpart S (see 29 CFR 1926.803(f)(1)). As an
alternative to the OSHA decompression tables, the applicant proposes to
use newer decompression schedules (the 1992 French Decompression
Tables) that rely on staged decompression and supplement breathing air
used during decompression with air or oxygen (as appropriate).\4\ The
applicant asserts decompression protocols using the 1992 French
Decompression Tables for air or oxygen as specified by the Potomac
River Tunnel Project-specific HOM are safer for tunnel workers than the
decompression protocols specified in Appendix A of 29 CFR 1926, subpart
S. Accordingly, the applicant would commit to following the
decompression procedures described in that HOM, which would require it
to follow the 1992 French Decompression Tables to decompress CAWs after
they exit the hyperbaric conditions in the working chamber.
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\4\ In 1992, the French Ministry of Labour replaced the 1974
French Decompression Tables with the 1992 French Decompression
Tables, which differ from OSHA's decompression tables in Appendix A
by using: (1) staged decompression as opposed to continuous (linear)
decompression; (2) decompression tables based on air or both air and
pure oxygen; and (3) emergency tables when unexpected exposure times
occur (up to 30 minutes above the maximum allowed working time).
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Depending on the maximum working pressure and exposure times, the
1992 French Decompression Tables provide for air decompression with or
without oxygen. CBNA asserts that oxygen decompression has many
benefits, including (1) keeping the partial pressure of nitrogen in the
lungs as low as possible; (2) keeping external pressure as low as
possible to reduce the formation of bubbles in the blood; (3) removing
nitrogen from the lungs and arterial blood and increasing the rate of
nitrogen elimination; (4) improving the quality of breathing during
decompression stops so that workers are less tired and to prevent bone
necrosis; (5) reducing decompression time by about 33 percent as
compared to air decompression; and (6) reducing inflammation.
In addition, the project-specific HOM requires a physician
certified in hyperbaric medicine to manage the medical condition of
CAWs during hyperbaric exposures and decompression. A trained and
experienced man-lock attendant is also required to be present during
hyperbaric exposures and decompression. This man-lock attendant is to
operate the hyperbaric system to ensure compliance with the specified
decompression table. A hyperbaric supervisor, who is trained in
hyperbaric operations, procedures, and safety, directly oversees all
hyperbaric interventions and ensures that staff follow the procedures
delineated in the HOM or by the attending physician.
C. Variance From Paragraph (g)(1)(iii) of 29 CFR 1926.803,
Automatically Regulated Continuous Decompression
The applicant is applying for a permanent variance from the OSHA
standard at 29 CFR 1926.803(g)(1)(iii), which requires automatic
controls to regulate decompression. As noted above, the applicant is
committed to conducting the staged decompression according to the 1992
French Decompression Tables under the direct control of the trained
man-lock attendant and under the oversight of the hyperbaric
supervisor.
Breathing air under hyperbaric conditions increases the amount of
nitrogen gas dissolved in a CAW's tissues. The greater the hyperbaric
pressure under these conditions and the more time spent under the
increased pressure, the greater the amount of nitrogen gas dissolved in
the tissues. When the pressure decreases during decompression, tissues
release the dissolved nitrogen gas into the blood system, which then
carries the nitrogen gas to the lungs for elimination through
exhalation. Releasing hyperbaric pressure too rapidly during
decompression can increase the size of the bubbles formed by nitrogen
gas in the blood system, resulting in decompression illness (DCI),
commonly referred to as ``the bends.'' This description of the etiology
of DCI is consistent with current scientific theory and research on the
issue.
The 1992 French Decompression Tables proposed for use by the
applicant provide for stops during worker decompression (i.e., staged
decompression) to control the release of nitrogen gas from tissues into
the blood system. Studies show that staged decompression, in
combination with other features of the 1992 French Decompression Tables
such as the use of oxygen, result in a lower incidence of DCI than the
use of automatically regulated continuous decompression.\5\
[[Page 34905]]
In addition, the applicant asserts that staged decompression
administered in accordance with its HOM is at least as effective as an
automatic controller in regulating the decompression process because
the HOM includes a hyperbaric supervisor who directly supervises all
hyperbaric interventions and ensures that the man-lock attendant, who
is a competent person in the manual control of hyperbaric systems,
follows the schedule specified in the decompression tables, including
stops.
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\5\ See, e.g., Dr. Eric Kindwall, EP (1997), Compressed air
tunneling and caisson work decompression procedures: development,
problems, and solutions. Undersea and Hyperbaric Medicine, 24(4),
pp. 337-345. This article reported 60 treated cases of DCI among
4,168 exposures between 19 and 31 p.s.i.g. over a 51-week contract
period, for a DCI incidence of 1.44% for the decompression tables
specified by the OSHA standard. Dr. Kindwall notes that the use of
automatically regulated continuous decompression in the Washington
State safety standards for compressed-air work (from which OSHA
derived its decompression tables) was at the insistence of
contractors and the union, and against the advice of the expert who
calculated the decompression table and recommended using staged
decompression. Dr. Kindwall then states, ``Continuous decompression
is inefficient and wasteful. For example, if the last stage from 4
p.s.i.g. . . . to the surface took 1h, at least half the time is
spent at pressures less than 2 p.s.i.g. . . ., which provides less
and less meaningful bubble suppression . . . .'' In addition, Dr.
Kindwall addresses the continuous-decompression protocol in the OSHA
compressed-air standard for construction, noting that ``[a]side from
the tables for saturation diving to deep depths, no other widely
used or officially approved diving decompression tables use straight
line, continuous decompressions at varying rates. Stage
decompression is usually the rule, since it is simpler to control.''
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D. Variance From Paragraph (g)(1)(xvii) of 29 CFR 1926.803, Requirement
of Special Decompression Chamber
The OSHA compressed-air standard for construction requires
employers to use a special decompression chamber of sufficient size to
accommodate all CAWs being decompressed at the end of the shift when
total decompression time exceeds 75 minutes (see 29 CFR
1926.803(g)(1)(xvii)). Use of the special decompression chamber enables
CAWs to move about and flex their joints to prevent neuromuscular
problems during decompression.
Space limitations in TBM do not allow for the installation and use
of an additional special decompression lock or chamber. The applicant
proposes that it be permitted to rely on the man-locks and staging
chamber in lieu of adding a separate, special decompression chamber.
Because only a few workers out of the entire crew are exposed to
hyperbaric pressure, the man-locks (which, as noted earlier, connect
directly to the working chamber) and the staging chamber are of
sufficient size to accommodate all of the exposed workers during
decompression. The applicant uses the existing man-locks, each of which
adequately accommodates a three-member crew for this purpose when
decompression lasts up to 75 minutes. When decompression exceeds 75
minutes, crews can open the door connecting the two compartments in
each man-lock (during decompression stops) or exit the man-lock and
move into the staging chamber where additional space is available. The
applicant asserts that this alternative arrangement is as effective as
a special decompression chamber in that it has sufficient space for all
the CAWs at the end of a shift and enables the CAWs to move about and
flex their joints to prevent neuromuscular problems.
III. Agency Preliminary Determinations
After reviewing the proposed alternatives, OSHA has preliminarily
determined that the applicant's proposed alternatives on the whole,
subject to the conditions in the request and imposed by this interim
order, provide measures that are as safe and healthful as those
required by the cited OSHA standards addressed in section II of this
notice.
In addition, OSHA has preliminarily determined that each of the
following alternatives are at least as effective as the specified OSHA
requirements:
A. 29 CFR 1926.803(f)(1)
CBNA has proposed to implement equally effective alternative
measures to the requirement in 29 CFR 1926.803(f)(1) for compliance
with OSHA's decompression tables. The project-specific HOM specifies
the procedures and personnel qualifications for performing work safely
during the compression and decompression phases of interventions. The
HOM also specifies the decompression tables the applicant proposes to
use (the 1992 French Decompression Tables). Depending on the maximum
working pressure and exposure times during the interventions, the
tables provide for decompression using air, pure oxygen, or a
combination of air and oxygen. The decompression tables also include
delays or stops for various time intervals at different pressure levels
during the transition to atmospheric pressure (i.e., staged
decompression). In all cases, a physician certified in hyperbaric
medicine will manage the medical condition of CAWs during
decompression. In addition, a trained and experienced man-lock
attendant, experienced in recognizing decompression sickness or
illnesses and injuries, will be present. Of key importance, a
hyperbaric supervisor, trained in hyperbaric operations, procedures,
and safety, will directly supervise all hyperbaric operations to ensure
compliance with the procedures delineated in the project-specific HOM
or by the attending physician.
As it did when granting the nine previous tunneling permanent
variances to IHP JV, Traylor JV, Tully JV, Salini-Impregilo JV,
McNally/Kiewit, Traylor-Shea, Traylor-Sundt JV, Ballard (Lower
Olentangy), Ballard (Bay Park) and one interim order to Ballard
(Suffolk), OSHA conducted a review of the scientific literature and
concluded that the alternative decompression method (i.e., the 1992
French Decompression Tables) CBNA proposed would be at least as safe as
the decompression tables specified by OSHA when applied by trained
medical personnel under the conditions that would be imposed by the
proposed variance.
Some of the literature indicates that the alternative decompression
method may be safer, concluding that decompression performed in
accordance with these tables resulted in a lower occurrence of DCI than
decompression conducted in accordance with the decompression tables
specified by the standard. For example, H.L. Andersen studied the
occurrence of DCI at maximum hyperbaric pressures ranging from 4
p.s.i.g. to 43 p.s.i.g. during construction of the Great Belt Tunnel in
Denmark (1992-1996).\6\ This project used the 1992 French Decompression
Tables to decompress the workers during part of the construction.
Andersen observed 6 DCI cases out of 7,220 decompression events and
reported that switching to the 1992 French Decompression tables reduced
the DCI incidence to 0.08% compared to a previous incidence rate of
0.14%. The DCI incidence in the study by H.L. Andersen is substantially
less than the DCI incidence reported for the decompression tables
specified in Appendix A.
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\6\ Anderson HL (2002). Decompression sickness during
construction of the Great Belt tunnel, Denmark. Undersea and
Hyperbaric Medicine, 29(3), pp. 172-188.
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OSHA found no studies in which the DCI incidence reported for the
1992 French Decompression Tables were higher than the DCI incidence
reported for the OSHA decompression tables.\7\
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\7\ Le P[eacute]chon JC, Barre P, Baud JP, Ollivier F (September
1996). Compressed air work--French Tables 1992--operational results.
JCLP Hyperbarie Paris, Centre Medical Subaquatique Interentreprise,
Marseille: Communication a l'EUBS, pp. 1-5 (see Ex. OSHA-2012-0036-
0005).
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OSHA's experience with the previous several variances, which all
incorporated nearly identical decompression plans and did not result in
safety issues, also provides evidence that the alternative procedure as
a whole is at least as effective for this type of tunneling project as
compliance with OSHA's decompression tables. The experience of State
Plans \8\ that either
[[Page 34906]]
granted variances (Nevada, Oregon and Washington) \9\ or promulgated a
new standard (California) \10\ for hyperbaric exposures occurring
during similar subaqueous tunnel-construction work, provide additional
evidence of the effectiveness of this alternative procedure.
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\8\ Under section 18 of the OSH Act, Congress expressly provides
that States and U.S. territories may adopt, with Federal approval, a
plan for the development and enforcement of occupational safety and
health standards. OSHA refers to such States and territories as
``State Plan States'' Occupational safety and health standards
developed by State Plan States must be at least as effective in
providing safe and healthful employment and places of employment as
the Federal standards (29 U.S.C. 667).
\9\ These state variances are available in the docket for the
2015 Traylor JV variance: Exs. OSHA-2012-0035-0006 (Nevada), OSHA-
2012-0035-0005 (Oregon), and OSHA-2012-0035-0004 (Washington).
\10\ See California Code of Regulations, Title 8, Subchapter 7,
Group 26, Article 154, available at <a href="http://www.dir.ca.gov/title8/sb7g26a154.html">http://www.dir.ca.gov/title8/sb7g26a154.html</a>.
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B. 29 CFR 1926.803(g)(1)(iii)
CBNA developed, and proposed to implement, an equally effective
alternative to 29 CFR 1926.803(g)(1)(iii), which requires the use of
automatic controllers that continuously decrease pressure to achieve
decompression in accordance with the tables specified by the standard.
The applicant's alternative includes using the 1992 French
Decompression Tables for guiding staged decompression to achieve lower
occurrences of DCI, using a trained and competent attendant for
implementing appropriate hyperbaric entry and exit procedures, and
providing a competent hyperbaric supervisor and attending physician
certified in hyperbaric medicine to oversee all hyperbaric operations.
In reaching this preliminary conclusion, OSHA again notes the
experience of previous nearly identical tunneling variances, the
experiences of State Plan States, and a review of the literature and
other information noted earlier.
C. 29 CFR 1926.803(g)(1)(xvii)
CBNA developed, and proposed to implement, an effective alternative
to the use of the special decompression chamber required by 29 CFR
1926.803(g)(1)(xvii). The TBM's man-lock and working chamber appear to
satisfy all of the conditions of the special decompression chamber,
including that they provide sufficient space for the maximum crew of
three CAWs to stand up and move around, and safely accommodate
decompression times up to 360 minutes. Therefore, again noting OSHA's
previous experience with nearly identical variances including the same
alternative, OSHA preliminarily determined that the TBM's man-lock and
working chamber function as effectively as the special decompression
chamber required by the standard.
Pursuant to section 6(d) of the Occupational Safety and Health Act
of 1970 (29 U.S.C. 655), and based on the record discussed above, the
agency preliminarily finds that when the employer complies with the
conditions of the proposed variance, the working conditions of the
employer's workers would be at least as safe and healthful as if the
employer complied with the working conditions specified by paragraphs
(f)(1), (g)(1)(iii), and (g)(1)(xvii) of 29 CFR 1926.803.
IV. Grant of Interim Order, Proposal for Permanent Variance, and
Request for Comment
OSHA hereby announces the preliminary decision to grant an interim
order allowing CBNA's CAWs to perform interventions in hyperbaric
conditions not exceeding 50 p.s.i.g. during the Potomac River Tunnel
Project, subject to the conditions that follow in this document. This
interim order will remain in effect until completion of the Potomac
River Tunnel Project or until the agency modifies or revokes the
interim order or makes a final decision on CBNA's application for a
permanent variance. During the period starting with the publication of
this notice until completion of the Potomac River Tunnel Project, or
until the agency modifies or revokes the interim order or makes a final
decision on the application for a permanent variance, CBNA is required
to comply fully with the conditions of the interim order as an
alternative to complying with the following requirements of 29 CFR
1926.803 (hereinafter, the standard) that:
1. Require the use of decompression values specified by the
decompression tables in Appendix A of the compressed-air standard (29
CFR 1926.803(f)(1));
2. Require the use of automated operational controls (29 CFR
1926.803(g)(1)(iii)); and
3. Require the use of a special decompression chamber (29 CFR
1926.803(g)(1)(xvii)).
In order to avail itself of the interim order, CBNA must: (1)
comply with the conditions listed in the interim order for the period
starting with the grant of the interim order and ending with CBNA's
completion of the Potomac River Tunnel Project (or until the agency
modifies or revokes the interim order or makes a decision on its
application for a permanent variance); (2) comply fully with all other
applicable provisions of 29 CFR part 1926; and (3) provide a copy of
this Federal Register notice to all employees affected by the proposed
conditions, including the affected employees of other employers, using
the same means it used to inform these employees of its application for
a permanent variance.
OSHA is also proposing that the same requirements (see above
section III) would apply to a permanent variance if OSHA ultimately
issues one for this project. OSHA requests comment on those conditions
as well as OSHA's preliminary determination that the specified
alternatives and conditions would provide a workplace as safe and
healthful as those required by the standard from which a variance is
sought. After reviewing comments, OSHA will publish in the Federal
Register the agency's final decision granting or denying a permanent
variance.
V. Description of the Specified Conditions of the Interim Order and the
Application for a Permanent Variance
This section describes the alternative means of compliance with 29
CFR 1926.803(f)(1), (g)(1)(iii), and (g)(1)(xvii) and provides
additional detail regarding the proposed conditions that form the basis
of CBNA's application for an interim order and permanent variance. The
conditions are listed below. For brevity, the discussion that follows
refers only to the permanent variance, but the same conditions apply to
the interim order.
Proposed Condition A: Scope
The scope of the proposed permanent variance would limit coverage
to the work situations specified. Clearly defining the scope of the
proposed permanent variance provides CBNA, CBNA's employees, potential
future applicants, other stakeholders, the public, and OSHA with
necessary information regarding the work situations in which the
proposed permanent variance would apply. To the extent that CBNA
exceeds the defined scope of this variance, it would be required to
comply with OSHA's standards.
Pursuant to 29 CFR 1905.11, an employer (or class or group of
employers) \11\ may request a permanent variance for a specific
workplace or workplaces. If OSHA approves a permanent variance, it
would apply only to the specific employer(s) that submitted the
application and only to the specific workplace or workplaces designated
as part of the project. In this
[[Page 34907]]
instance, if OSHA were to grant a permanent variance, it would apply to
only the applicant, CBNA, and only the Potomac River Tunnel Project. As
a result, it is important to understand that if OSHA were to grant CBNA
a permanent variance, it would not apply to any other employers, or to
projects the applicant may undertake in the future.
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\11\ A class or group of employers (such as members of a trade
alliance or association) may apply jointly for a variance provided
an authorized representative for each employer signs the application
and the application identifies each employer's affected facilities.
---------------------------------------------------------------------------
Proposed Condition B: Duration
The interim order is only intended as a temporary measure pending
OSHA's decision on the permanent variance, so this condition specifies
the duration of the order. If OSHA approves a permanent variance, it
would specify the duration of the permanent variance as the remainder
of the Potomac River Tunnel Project.
Proposed Condition C: List of Abbreviations
The proposed condition defines a number of abbreviations used in
the proposed permanent variance. OSHA believes that defining these
abbreviations serve to clarify and standardize their usage, thereby
enhancing the applicant's and its employees' understanding of the
conditions specified by the proposed permanent variance.
Proposed Condition D: Definitions
The proposed condition defines a series of terms, mostly technical
terms, used in the proposed permanent variance to standardize and
clarify their meaning. OSHA believes that defining these terms serves
to enhance the applicant's and its employees' understanding of the
conditions specified by the proposed permanent variance.
Proposed Condition E: Safety and Health Practices
This proposed condition requires the applicant to develop and
submit to OSHA a HOM specific to the Potomac River Tunnel Project at
least six months before using the TBM for tunneling operations. The
applicant must also submit, at least six months before using the TBM,
proof that the TBM's hyperbaric chambers have been designed,
fabricated, inspected, tested, marked, and stamped in accordance with
the requirements of ASME PVHO-1.2019 (or the most recent edition of
Safety Standards for Pressure Vessels for Human Occupancy). These
requirements ensure that the applicant develops hyperbaric safety and
health procedures suitable for the project.
The submission of the HOM to OSHA, which CBNA has already
completed, enables OSHA to determine whether the safety and health
instructions and measures it specifies are appropriate to the field
conditions of the tunnel (including expected geological conditions),
conform to the conditions of the variance, and adequately protect the
safety and health of the CAWs. It also facilitates OSHA's ability to
ensure that the applicant is complying with these instructions and
measures. The requirement for proof of compliance with ASME PVHO-1.2019
is intended to ensure that the equipment is structurally sound and
capable of performing to protect the safety of the employees exposed to
hyperbaric pressure.
Additionally, the proposed condition includes a series of related
hazard prevention and control requirements and methods (e.g.,
decompression tables, job hazard analyses (JHA), operations and
inspections checklists, incident investigation, and recording and
notification to OSHA of recordable hyperbaric injuries and illnesses)
designed to ensure the continued effective functioning of the
hyperbaric equipment and operating system.
Proposed Condition F: Communication
This proposed condition requires the applicant to develop and
implement an effective system of information sharing and communication.
Effective information sharing and communication are intended to ensure
that affected workers receive updated information regarding any safety-
related hazards and incidents, and corrective actions taken, prior to
the start of each shift. The proposed condition also requires the
applicant to ensure that reliable means of emergency communications are
available and maintained for affected workers and support personnel
during hyperbaric operations. The availability of such reliable means
of communications would enable affected workers and support personnel
to respond quickly and effectively to hazardous conditions or
emergencies that may develop during TBM operations.
Proposed Condition G: Worker Qualification and Training
This proposed condition requires the applicant to develop and
implement an effective qualification and training program for affected
workers. The proposed condition specifies the factors that an affected
worker must know to perform safely during hyperbaric operations,
including how to enter, work in, and exit from hyperbaric conditions
under both normal and emergency conditions. Having well-trained and
qualified workers performing hyperbaric intervention work is intended
to ensure that they recognize, and respond appropriately to, hyperbaric
safety and health hazards. These qualification and training
requirements enable affected workers to cope effectively with
emergencies, as well as the discomfort and physiological effects of
hyperbaric exposure, thereby preventing worker injury, illness, and
fatalities.
Paragraph (2)(e) of this proposed condition requires the applicant
to provide affected workers with information they can use to contact
the appropriate healthcare professionals if the workers believe they
are developing hyperbaric-related health effects. This requirement
provides for early intervention and treatment of DCI and other health
effects resulting from hyperbaric exposure, thereby reducing the
potential severity of these effects.
Proposed Condition H: Inspections, Tests, and Accident Prevention
Proposed Condition H requires the applicant to develop, implement,
and operate a program of frequent and regular inspections of the TBM's
hyperbaric equipment and support systems, and associated work areas.
This condition would help to ensure the safe operation and physical
integrity of the equipment and work areas necessary to conduct
hyperbaric operations. The condition would also enhance worker safety
by reducing the risk of hyperbaric-related emergencies.
Paragraph (3) of this proposed condition requires the applicant to
document tests, inspections, corrective actions, and repairs involving
the TBM, and maintain these documents at the jobsite for the duration
of the job. This requirement would provide the applicant with
information needed to schedule tests and inspections to ensure the
continued safe operation of the equipment and systems, and to determine
that the actions taken to correct defects in hyperbaric equipment and
systems were appropriate, prior to returning them to service.
Proposed Condition I: Compression and Decompression
This proposed condition would require the applicant to consult with
the designated medical advisor regarding special compression or
decompression procedures appropriate for any unacclimated CAW and then
implement the procedures recommended by the medical consultant. This
proposed provision would ensure that the applicant consults with the
medical advisor, and involves the medical
[[Page 34908]]
advisor in the evaluation, development, and implementation of
compression or decompression protocols appropriate for any CAW
requiring acclimation to the hyperbaric conditions encountered during
TBM operations. Accordingly, CAWs requiring acclimation would have an
opportunity to acclimate prior to exposure to these hyperbaric
conditions. OSHA believes this condition would prevent or reduce
adverse reactions among CAWs to the effects of compression or
decompression associated with the intervention work they perform in the
TBM.
Proposed Condition J: Recordkeeping
Under OSHA's existing recordkeeping requirements in 29 CFR part
1904 regarding Recording and Reporting Occupational Injuries and
Illnesses, the employer must maintain a record of any recordable
injury, illness, or fatality (as defined by 29 CFR part 1904) resulting
from exposure of an employee to hyperbaric conditions by completing the
OSHA Form 301 Incident Report and OSHA Form 300 Log of Work-Related
Injuries and Illnesses. The applicant did not seek a variance from this
standard and therefore CBNA must comply fully with those requirements.
Examples of important information to include on the OSHA Form 301
Injury and Illness Incident Report (along with the corresponding
questions on the form) are:
Q14
<bullet> the task performed;
<bullet> the composition of the gas mixture (e.g., air or oxygen);
<bullet> an estimate of the CAW's workload;
<bullet> the maximum working pressure;
<bullet> temperature in the work and decompression environments;
<bullet> unusual occurrences, if any, during the task or
decompression
Q15
<bullet> time of symptom onset;
<bullet> duration between decompression and onset of symptoms
Q16
<bullet> type and duration of symptoms;
<bullet> a medical summary of the illness or injury
Q17
<bullet> duration of the hyperbaric intervention;
<bullet> possible contributing factors;
<bullet> the number of prior interventions completed by the injured
or ill CAW; and the pressure to which the CAW was exposed during those
interventions.\12\
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\12\ See 29 CFR 1904 Recording and Reporting Occupational
Injuries and Illnesses (<a href="http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9631">http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9631</a>); recordkeeping
forms and instructions (<a href="http://www.osha.gov/recordkeeping/RKform300pkg-fillable-enabled.pdf">http://www.osha.gov/recordkeeping/RKform300pkg-fillable-enabled.pdf</a>); and OSHA Recordkeeping Handbook
(<a href="http://www.osha.gov/recordkeeping/handbook/index.html">http://www.osha.gov/recordkeeping/handbook/index.html</a>).
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Proposed Condition J would add additional reporting
responsibilities, beyond those already required by the OSHA standard.
The applicant would be required to maintain records of specific factors
associated with each hyperbaric intervention. The information gathered
and recorded under this provision, in concert with the information
provided under proposed Condition K (using OSHA Form 301 Injury and
Illness Incident Report to investigate and record hyperbaric recordable
injuries as defined by 29 CFR 1904.4, 1904.7, 1904.8-1904.12), would
enable the applicant and OSHA to assess the effectiveness of the
permanent variance in preventing DCI and other hyperbaric-related
effects.
Proposed Condition K: Notifications
Under the proposed condition, the applicant is required, within
specified periods of time, to notify OSHA of: (1) any recordable
injury, illness, in-patient hospitalization, amputation, loss of an
eye, or fatality that occurs as a result of hyperbaric exposures during
TBM operations within 8 hours; (2) provide OSHA a copy of the
hyperbaric exposures incident investigation report (using OSHA Form 301
Injury and Illness Incident Report) of these events within 24 hours of
the incident; (3) include on OSHA Form 301 Injury and Illness Incident
Report information on the hyperbaric conditions associated with the
recordable injury or illness, the root-cause determination, and
preventive and corrective actions identified and implemented; (4)
provide the certification along with the OSHA Form 310, that affected
workers were informed of the incident and the results of the incident
investigation; (5) notify OSHA's Office of Technical Programs and
Coordination Activities (OTPCA) and the OSHA Baltimore/Washington Area
Office within 15 working days should the applicant need to revise the
HOM to accommodate changes in its compressed-air operations that affect
CBNA's ability to comply with the conditions of the proposed permanent
variance; and (6) provide OTPCA and the OSHA Baltimore/Washington Area
Office, at the end of the project, with a report evaluating the
effectiveness of the decompression tables within 30 days of the
completion of the Potomac River Tunnel Project.
It should be noted that the requirement for completing and
submitting the hyperbaric exposure-related (recordable) incident
investigation report (OSHA 301 Injury and Illness Incident Report) is
more restrictive than the current recordkeeping requirement of
completing OSHA Form 301 Injury and Illness Incident Report within 7
calendar days of the incident (1904.29(b)(3)). This modified, more
stringent incident investigation and reporting requirement is
restricted to intervention-related hyperbaric (recordable) incidents
only. Providing rapid notification to OSHA is essential because time is
a critical element in OSHA's ability to determine the continued
effectiveness of the variance conditions in preventing hyperbaric
incidents, and the applicant's identification and implementation of
appropriate corrective and preventive actions.
Further, these notification requirements also enable the applicant,
its employees, and OSHA to assess the effectiveness of the permanent
variance in providing the requisite level of safety to the applicant's
workers and based on this assessment, whether to revise or revoke the
conditions of the proposed permanent variance. Timely notification
permits OSHA to take whatever action may be necessary and appropriate
to prevent possible further injuries and illnesses. Providing
notification to employees informs them of the precautions taken by the
applicant to prevent similar incidents in the future.
Additionally, this proposed condition requires the applicant to
notify OSHA no later than seven (7) days of having knowledge that it
will cease to do business, have a new address or location for the main
office, or transfer the operations covered by the proposed permanent
variance to a successor company. In addition, the condition specifies
that the transfer of the permanent variance to a successor company must
be approved by OSHA. These requirements allow OSHA to communicate
effectively with the applicant regarding the status of the proposed
permanent variance and expedite the agency's administration and
enforcement of the permanent variance. Stipulating that an applicant is
required to have OSHA's approval to transfer a variance to a successor
company provides assurance that the successor company has knowledge of,
and will comply with, the conditions specified by the proposed
permanent variance, thereby ensuring the safety of workers involved in
performing the
[[Page 34909]]
operations covered by the proposed permanent variance.
VI. Specific Conditions of the Interim Order and the Proposed Permanent
Variance
The following conditions apply to the interim order OSHA is
granting to CBNA for the Potomac River Tunnel Project. These conditions
specify the alternative means of compliance with the requirements of
paragraphs 29 CFR 1926.803(f)(1), (g)(1)(iii), and (g)(1)(xvii). In
addition, these conditions are specific to the alternative means of
compliance with these requirements that OSHA is proposing for CBNA's
permanent variance. To simplify the presentation of the conditions,
OSHA generally refers only to the conditions of the proposed permanent
variance, but the same conditions apply to the interim order except
where otherwise noted.\13\
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\13\ In these conditions, OSHA is using the future conditional
form of the verb (e.g., ``would''), which pertains to the
application for a permanent variance (designated as ``Permanent
Variance'') but the conditions are mandatory for purposes of the
interim order.
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The conditions would apply with respect to all employees of CBNA
exposed to hyperbaric conditions. These conditions are outlined in this
section:
A. Scope
The interim order applies, and the permanent variance would apply
only when CBNA stops the tunnel-boring work, pressurizes the working
chamber, and the CAWs either enter the working chamber to perform an
intervention (i.e., inspect, maintain, or repair the mechanical-
excavation components), or exit the working chamber after performing
interventions.
The interim order and proposed permanent variance apply only to
work:
1. That occurs in conjunction with construction of the Potomac
River Tunnel Project, a tunnel constructed using advanced shielded
mechanical-excavation techniques and involving operation of an TBM;
2. In the TBM's forward section (the working chamber) and
associated hyperbaric chambers used to pressurize and decompress
employees entering and exiting the working chamber; and
3. Performed in compliance with all applicable provisions of 29 CFR
part 1926 except for the requirements specified by 29 CFR
1926.803(f)(1), (g)(1)(iii), and (g)(1)(xvii).
B. Duration
The interim order granted to CBNA will remain in effect until CBNA
completes the Potomac River Tunnel Project, OSHA modifies or revokes
this interim order, or OSHA grants CBNA's request for a permanent
variance. The proposed permanent variance, if granted, would remain in
effect until the completion of CBNA's Potomac River Tunnel Project or
until modified or revoked by OSHA pursuant to 29 CFR 1905.13(a)(2).
C. List of Abbreviations
Abbreviations used throughout this proposed permanent variance
would include the following:
1. CAW--Compressed-air worker
2. CFR--Code of Federal Regulations
3. DCI--Decompression Illness
4. DMT--Diver Medical Technician
5. TBM--Earth Pressure Balanced Tunnel Boring Machine
6. HOM--Hyperbaric Operations Manual
7. JHA--Job hazard analysis
8. OSHA--Occupational Safety and Health Administration
9. OTPCA--Office of Technical Programs and Coordination Activities
D. Definitions
The following definitions would apply to this proposed permanent
variance. These definitions would supplement the definitions in CBNA's
project-specific HOM.
1. Affected employee or worker--an employee or worker who is
affected by the conditions of this proposed permanent variance, or any
one of his or her authorized representatives. The term ``employee'' has
the meaning defined and used under the Occupational Safety and Health
Act of 1970 (29 U.S.C. 651 et seq.).
2. Atmospheric pressure--the pressure of air at sea level,
generally 14.7 pounds per square inch absolute (p.s.i.a)., 1 atmosphere
absolute, or 0 p.s.i.g.
3. Compressed-air worker--an individual who is specially trained
and medically qualified to perform work in a pressurized environment
while breathing air at pressures not exceeding 49.5 p.s.i.g.
4. Competent person--an individual who is capable of identifying
existing and predictable hazards in the surroundings or working
conditions that are unsanitary, hazardous, or dangerous to employees,
and who has authorization to take prompt corrective measures to
eliminate them.\14\
---------------------------------------------------------------------------
\14\ Adapted from 29 CFR 1926.32(f).
---------------------------------------------------------------------------
5. Decompression illness--an illness (also called decompression
sickness or ``the bends'') caused by gas bubbles appearing in body
compartments due to a reduction in ambient pressure. Examples of
symptoms of decompression illness include, but are not limited to:
joint pain (also known as the ``bends'' for agonizing pain or the
``niggles'' for slight pain); areas of bone destruction (termed
dysbaric osteonecrosis); skin disorders (such as cutis marmorata, which
causes a pink marbling of the skin); spinal cord and brain disorders
(such as stroke, paralysis, paresthesia, and bladder dysfunction);
cardiopulmonary disorders, such as shortness of breath; and arterial
gas embolism (gas bubbles in the arteries that block blood flow).\15\
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\15\ See Appendix 10 of ``A Guide to the Work in Compressed-Air
Regulations 1996,'' published by the United Kingdom Health and
Safety Executive available from NIOSH at <a href="http://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-254/compReg1996.pdf">http://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-254/compReg1996.pdf</a> pdf.
Note: Health effects associated with hyperbaric intervention,
but not considered symptoms of DCI, can include: barotrauma (direct
damage to air-containing cavities in the body such as ears, sinuses,
and lungs); nitrogen narcosis (reversible alteration in
consciousness that may occur in hyperbaric environments and is
caused by the anesthetic effect of certain gases at high pressure);
and oxygen toxicity (a central nervous system condition resulting
from the harmful effects of breathing molecular oxygen
---------------------------------------------------------------------------
(O<INF>2</INF>) at elevated partial pressures).
6. Diver Medical Technician--Member of the dive team who is
experienced in first aid.
7. Earth Pressure Balanced Tunnel Boring Machine--the machinery
used to excavate a tunnel.
8. Hot work--any activity performed in a hazardous location that
may introduce an ignition source into a potentially flammable
atmosphere.\16\
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\16\ Also see 29 CFR 1926.1202 for examples of hot work.
---------------------------------------------------------------------------
9. Hyperbaric--at a higher pressure than atmospheric pressure.
10. Hyperbaric intervention--a term that describes the process of
stopping the TBM and preparing and executing work under hyperbaric
pressure in the working chamber for the purpose of inspecting,
replacing, or repairing cutting tools and/or the cutterhead structure.
11. Hyperbaric Operations Manual--a detailed, project-specific
health and safety plan developed and implemented by CBNA for working in
compressed air during the Potomac River Tunnel Project.
12. Job hazard analysis--an evaluation of tasks or operations to
identify potential hazards and to determine the necessary controls.
13. Man-lock--an enclosed space capable of pressurization and used
for compressing or decompressing any employee or material when either
is
[[Page 34910]]
passing into, or out of, a working chamber.
14. Medical Advisor--medical professional experienced in the
physical requirements of compressed air work and the treatment of
decompression illness.
15. Pressure--a force acting on a unit area. Usually expressed as
pounds per square inch (p.s.i.).
16. p.s.i.a.--pounds per square inch absolute, or absolute
pressure, is the sum of the atmospheric pressure and gauge pressure. At
sea level, atmospheric pressure is approximately 14.7 p.s.i.a. Adding
14.7 to a pressure expressed in units of p.s.i.g. will yield the
absolute pressure, expressed as p.s.i.a.
17. p.s.i.g.--pounds per square inch gauge, a common unit of
pressure; pressure expressed as p.s.i.g. corresponds to pressure
relative to atmospheric pressure. At sea level, atmospheric pressure is
approximately 14.7 p.s.i.a Subtracting 14.7 from a pressure expressed
in units of p.s.i.a. yields the gauge pressure, expressed as p.s.i.g.
At sea level the gauge pressure is 0 psig.
18. Qualified person--an individual who, by possession of a
recognized degree, certificate, or professional standing, or who, by
extensive knowledge, training, and experience, successfully
demonstrates an ability to solve or resolve problems relating to the
subject matter, the work, or the project.\17\
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\17\ Adapted from 29 CFR 1926.32(m).
---------------------------------------------------------------------------
19. Working chamber--an enclosed space in the TBM in which CAWs
perform interventions, and which is accessible only through a man-lock.
E. Safety and Health Practices
1. CBNA would have to adhere to the project-specific HOM submitted
to OSHA as part of the application (see OSHA-2025-0002-0003). The HOM
provides the minimum requirements regarding expected safety and health
hazards (including anticipated geological conditions) and hyperbaric
exposures during the tunnel construction project.
2. CBNA would have to demonstrate that the TBM on the project is
designed, fabricated, inspected, tested, marked, and stamped in
accordance with the requirements of ASME PVHO-1.2019 (or most recent
edition of Safety Standards for Pressure Vessels for Human Occupancy)
for the TBM's hyperbaric chambers.
3. CBNA would have to implement the safety and health instructions
included in the manufacturer's operations manuals for the TBM, and the
safety and health instructions provided by the manufacturer for the
operation of decompression equipment.
4. CBNA would have to ensure that there are no exposures to
pressures greater than 49.5 p.s.i.g.
5. CBNA would have to ensure that air or oxygen is the only
breathing gas in the working chamber.
6. CBNA would have to follow the 1992 French Decompression Tables
for air or oxygen decompression as specified in the HOM; specifically,
the extracted portions of the 1992 French Decompression tables titled,
``French Regulation Air Standard Tables.''
7. CBNA would have to equip man-locks used by employees with an air
or oxygen delivery system, as specified by the HOM for the project.
CBNA would be prohibited from storing in the tunnel any oxygen or other
compressed gases used in conjunction with hyperbaric work.
8. Workers performing hot work under hyperbaric conditions would
have to use flame-retardant personal protective equipment and clothing.
9. In hyperbaric work areas, CBNA would have to maintain an
adequate fire-suppression system approved for hyperbaric work areas.
10. CBNA would have to develop and implement one or more Job Hazard
Analysis (JHA) for work in the hyperbaric work areas, and review,
periodically and as necessary (e.g., after making changes to a planned
intervention that affects its operation), the contents of the JHAs with
affected employees. The JHAs would have to include all the job
functions that the risk assessment \18\ indicates are essential to
prevent injury or illness.
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\18\ See ANSI/AIHA Z10-2012, American National Standard for
Occupational Health and Safety Management Systems, for reference.
---------------------------------------------------------------------------
11. CBNA would have to develop a set of checklists to guide
compressed-air work and ensure that employees follow the procedures
required by the proposed permanent variance and this interim order
(including all procedures required by the HOM approved by OSHA for the
project, which this proposed variance would incorporate by reference).
The checklists would have to include all steps and equipment functions
that the risk assessment indicates are essential to prevent injury or
illness during compressed-air work.
12. CBNA would have to ensure that the safety and health provisions
of this project-specific HOM adequately protect the workers of all
contractors and subcontractors involved in hyperbaric operations for
the project to which the HOM applies.
F. Communication
CBNA would have to:
1. Prior to beginning a shift, implement a system that informs
workers exposed to hyperbaric conditions of any hazardous occurrences
or conditions that might affect their safety, including hyperbaric
incidents, gas releases, equipment failures, earth or rock-slides,
cave-ins, flooding, fires, or explosions.
2. Provide a power-assisted means of communication among affected
workers and support personnel in hyperbaric conditions where unassisted
voice communication is inadequate.
(a) Use an independent power supply for powered communication
systems, and these systems would have to operate such that use or
disruption of any one phone or signal location will not disrupt the
operation of the system from any other location.
(b) Test communication systems at the start of each shift and as
necessary thereafter to ensure proper operation.
G. Worker Qualifications and Training
CBNA would have to:
1. Ensure that each affected worker receives effective training on
how to safely enter, work in, exit from, and undertake emergency
evacuation or rescue from, hyperbaric conditions, and document this
training.
2. Provide effective instruction on hyperbaric conditions, before
beginning hyperbaric operations, to each worker who performs work, or
controls the exposure of others, and document this instruction. The
instruction would need to include:
(a) The physics and physiology of hyperbaric work;
(b) Recognition of pressure-related injuries;
(c) Information on the causes and recognition of the signs and
symptoms associated with decompression illness, and other hyperbaric
intervention-related health effects (e.g., barotrauma, nitrogen
narcosis, and oxygen toxicity);
(d) How to avoid discomfort during compression and decompression;
(e) Information the workers can use to contact the appropriate
healthcare professionals should the workers have concerns that they may
be experiencing adverse health effects from hyperbaric exposure; and
(f) Procedures and requirements applicable to the employee in the
project-specific HOM.
3. Repeat the instruction specified in paragraph (G) of this
proposed condition periodically and as necessary (e.g., after making
changes to its hyperbaric operations).
[[Page 34911]]
4. When conducting training for its hyperbaric workers, make this
training available to OSHA personnel and notify the OTPCA at OSHA's
national office and OSHA's Baltimore/Washington Area Office before the
training takes place.
H. Inspections, Tests, and Accident Prevention
1. CBNA would have to initiate and maintain a program of frequent
and regular inspections of the TBM's hyperbaric equipment and support
systems (such as temperature control, illumination, ventilation, and
fire-prevention and fire-suppression systems), and hyperbaric work
areas, as required under 29 CFR 1926.20(b)(2), including:
(a) Developing a set of checklists to be used by a competent person
in conducting weekly inspections of hyperbaric equipment and work
areas; and
(b) Ensuring that a competent person conducts daily visual checks
and weekly inspections of the TBM.
2. Remove from service any equipment that constitutes a safety
hazard until it corrects the hazardous condition and has the correction
approved by a qualified person.
3. CBNA would have to maintain records of all tests and inspections
of the TBM, as well as associated corrective actions and repairs, at
the job site for the duration of the tunneling project and for 90 days
after the final project report is submitted to OSHA.
I. Compression and Decompression
CBNA would have to consult with its attending physician concerning
the need for special compression or decompression exposures appropriate
for CAWs not acclimated to hyperbaric exposure.
J. Recordkeeping
In addition to completing OSHA Form 301 Injury and Illness Incident
Report and OSHA Form 300 Log of Work-Related Injuries and Illnesses,
CBNA would have to maintain records of:
1. The date, times (e.g., time compression started, time spent
compressing, time performing intervention, time spent decompressing),
and pressure for each hyperbaric intervention.
2. The names of all supervisors and DMTs involved for each
intervention.
3. The name of each individual worker exposed to hyperbaric
pressure and the decompression protocols and results for each worker.
4. The total number of interventions and the amount of hyperbaric
work time at each pressure.
5. The results of the post-intervention physical assessment of each
CAW for signs and symptoms of decompression illness, barotrauma,
nitrogen narcosis, oxygen toxicity or other health effects associated
with work in compressed air for each hyperbaric intervention.
K. Notifications
1. To assist OSHA in administering the conditions specified herein,
CBNA would have to:
(a) Notify the OTPCA and the OSHA Baltimore/Washington Area Office,
at <a href="http://www.osha.gov/contactus/byoffice">www.osha.gov/contactus/byoffice</a> of any recordable injury, illness,
or fatality (by submitting the completed OSHA Form 301 Injuries and
Illness Incident Report) resulting from exposure of an employee to
hyperbaric conditions, including those that do not require
recompression treatment (e.g., nitrogen narcosis, oxygen toxicity,
barotrauma), but still meet the recordable injury or illness criteria
of 29 CFR 1904. The notification would have to be made within 8 hours
of the incident or 8 hours after becoming aware of a recordable injury,
illness, or fatality; a copy of the incident investigation (OSHA Form
301 Injuries and Illness Incident Report) must be submitted to OSHA
within 24 hours of the incident or 24 hours after becoming aware of a
recordable injury, illness, or fatality. In addition to the information
required by OSHA Form 301 Injuries and Illness Incident Report, the
incident-investigation report would have to include a root-cause
determination, and the preventive and corrective actions identified and
implemented.
(b) Provide certification to the OSHA Baltimore/Washington Area
Office within 15 working days of the incident that CBNA informed
affected workers of the incident and the results of the incident
investigation (including the root-cause determination and preventive
and corrective actions identified and implemented).
(c) Notify the OTPCA and the OSHA Baltimore/Washington Area Office
within 15 working days and in writing, of any change in the compressed-
air operations that affects CBNA's ability to comply with the proposed
conditions specified herein.
(d) Upon completion of the Potomac River Tunnel Project, evaluate
the effectiveness of the decompression tables used throughout the
project, and provide a written report of this evaluation to the OTPCA
and the OSHA Baltimore/Washington Area Office within 30 days after the
workers final day onsite.
Note: The evaluation report would have to contain summaries of:
(1) The number, dates, durations, and pressures of the hyperbaric
interventions completed; (2) decompression protocols implemented
(including composition of gas mixtures (air and/or oxygen), and the
results achieved; (3) the total number of interventions and the
number of hyperbaric incidents (decompression illnesses and/or
health effects associated with hyperbaric interventions as recorded
on OSHA Form 301 Injuries and Illness Incident Report and OSHA Form
300 Log of Work-Related Injuries and Illnesses, and relevant medical
diagnoses, and treating physicians' opinions); and (4) root causes
of any hyperbaric incidents, and preventive and corrective actions
identified and implemented.
(e) To assist OSHA in administering the proposed conditions
specified herein, inform the OTPCA and the OSHA Baltimore/Washington
Area Office as soon as possible, but no later than seven (7) days,
after it has knowledge that it will:
(i) Cease doing business;
(ii) Change the location and address of the main office for
managing the tunneling operations specified herein; or
(iii) Transfer the operations specified herein to a successor
company.
(f) Notify all affected employees of this proposed permanent
variance by the same means required to inform them of its application
for a permanent variance.
2. OSHA would have to approve the transfer of the permanent
variance to a successor company through a new application for a
permanent variance.
VII. Authority and Signature
Amanda Laihow, Acting Assistant Secretary of Labor for Occupational
Safety and Health, 200 Constitution Avenue NW, Washington, DC 20210,
authorized the preparation of this notice. Accordingly, the agency is
issuing this notice pursuant to 29 U.S.C. 655(6)(d), Secretary of
Labor's Order No. 7-2025 (90 FR 27878, June 30, 2025), and 29 CFR
1905.11.
Signed at Washington, DC, on July 7, 2025.
Amanda Laihow,
Acting Assistant Secretary of Labor for Occupational Safety and Health.
[FR Doc. 2025-13885 Filed 7-23-25; 8:45 am]
BILLING CODE 4510-26-P
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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.