Notice2025-13889
McNally Tunneling Corp./ASI Marine Southerly Tunnel and Consolidation Project; 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 McNally Tunneling Corp./ASI Marine (McNally/ASI Marine) 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 McNally/ASI Marine'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 34887-34897]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-13889]
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DEPARTMENT OF LABOR
Occupational Safety and Health Administration
[Docket No. OSHA-2025-0004]
McNally Tunneling Corp./ASI Marine Southerly Tunnel and
Consolidation Project; 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 McNally
Tunneling Corp./ASI Marine (McNally/ASI Marine) 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 McNally/ASI Marine'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
Southerly Tunnel and Consolidation (SOTC) Project for Cleveland, Ohio,
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-2025-0004). 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#066b636f6a6f686163742860746768656f75344662696a28616970"><span class="__cf_email__" data-cfemail="ef828a86838681888a9dc1899d8e818c869cddaf8b8083c1888099">[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#780a171a11160b171656131d0e1116381c1714561f170e"><span class="__cf_email__" data-cfemail="42302d202b2c312d2c6c2927342b2c02262d2e6c252d34">[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 July 16, 2024, McNally Tunneling Corp./ASI Marine (McNally/ASI
or the applicant), submitted under Section 6(d) of the Occupational
Safety and Health Act of 1970 (OSH 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-2025-0004-0002). This notice
addresses McNally/ASI's application for a permanent variance and
interim order for construction of the Southerly Tunnel and
Consolidation (SOTC) Project in Cleveland, Ohio, only and is not
applicable to future McNally/ASI Marine or McNally-related joint
venture tunneling projects.
Specifically, this notice addresses McNally/ASI Marine's
application for a permanent variance and interim order from the
provisions of the standard that: (1) prohibit compressed-air worker
exposure to pressures exceeding 50 pounds per square inch (p.s.i.)
except in an emergency (29 CFR 1926.803(e)(5)); \1\ (2) require the use
of the decompression values specified in decompression tables in
Appendix A of the compressed-air standard for construction (29 CFR
1926.803(f)(1)); and (3) require the use of automated operational
controls and a special decompression chamber (29 CFR
[[Page 34888]]
1926.803(g)(1)(iii) and .803(g)(1)(xvii), respectively).
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\1\ The decompression tables in Appendix A of subpart S express
the maximum working pressures as pounds per square inch gauge
(p.s.i.g.), with a maximum working pressure of 50 p.s.i.g.
Therefore, throughout this notice, OSHA expresses the 50 p.s.i.
value specified by 29 CFR 1926.803(e)(5) as 50 p.s.i.g., consistent
with the terminology in Appendix A, Table 1 of subpart S.
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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 underground
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 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.
McNally/ASI Marine asserts that generally 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.
McNally/ASI Marine's variance application indicated that the
maximum pressure to which it is likely to expose workers during project
interventions for the SOTC Project is 58 p.s.i. Therefore, to work
effectively, McNally/ASI Marine must perform hyperbaric interventions
in compressed air at pressures 16 percent higher than the maximum
pressure specified by the existing OSHA standard, 29 CFR
1926.803(e)(5), which states: ``No employee shall be subjected to
pressure exceeding 50 p.s.i.g. except in emergency'' (see footnote 1).
McNally/ASI Marine employs specially trained personnel for the
construction of the tunnel. To keep the machinery working effectively,
McNally 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 58 p.s.i.g., which exceeds the maximum pressure specified by the
existing OSHA standard at 29 CFR 1926.803(e)(5). 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.
McNally/ASI Marine 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, McNally/ASI Marine 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(e)(5) and (f)(1) and the decompression
tables in Appendix A of 29 CFR 1926, subpart S. Nevertheless, according
to McNally/ASI Marine, 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.
McNally/ASI Marine 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, a better application of hyperbaric medicine, and
the development of a project-specific Hyperbaric Operations Manual
(HOM), (OSHA-2025-0004-0003) 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 McNally/ASI Marine's application for
a permanent variance and interim order for the construction of the SOTC
Project in Cleveland, Ohio, OSHA has preliminarily determined that
McNally/ASI Marine 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
1905.11), the applicant has certified that it notified its workers \2\
of the variance 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
[[Page 34889]]
application. In addition, the applicant informed its workers and their
representatives of their rights to petition the Assistant Secretary of
Labor 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 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 Joint Venture for the New York
Economic Development Corporation's New York Siphon Tunnel project (79
FR 29809, May 23, 2014); (4) Salini-Impregilo/Healy Joint Venture 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 Joint
Venture 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 interim orders. 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.
B. Variance From Paragraph (e)(5) of 29 CFR 1926.803, Prohibition of
Exposure to Pressure Greater Than 50 p.s.i.g. (See Footnote 1)
The applicant states that it may perform hyperbaric interventions
at pressures up to 58 p.s.i.g. in the working chamber of the TBM; this
pressure exceeds the pressure limit of 50 p.s.i. specified for
nonemergency purposes by 29 CFR 1926.803(e)(5). The TBM has twin man-
locks, with each man-lock having 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.
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. As noted earlier, 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 staging chamber and the forward working
chamber. The staging chamber is the section of the working chamber
between the man-lock door and the entry door to the forward working
chamber. The forward working chamber is immediately behind the cutter
head and tunnel face.
McNally/ASI Marine will pressurize the working chamber to the level
required to maintain a stable tunnel face. Pressure in the staging
chamber ranges from atmospheric (no increased pressure) to a maximum
pressure equal to the pressure in the working chamber. The applicant
asserts that they may have to perform interventions at pressures up to
58 p.s.i.g.
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 maximum crew size allowed in the forward working chamber
is three. At certain hyperbaric pressures (i.e., when 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.
Further, the applicant asserts that it has developed a project-
specific HOM (OSHA-2025-0004-0003) that describes in detail the
hyperbaric procedures, the required medical examination used during the
tunnel-construction project, the standard operating procedures and the
emergency and contingency procedures. The procedures include using
experienced and knowledgeable man-lock attendants who have the training
and experience necessary to recognize and treat decompression illnesses
and injuries. The attendants are under the direct supervision of the
hyperbaric supervisor and attending physician. In addition, procedures
include medical screening and review of prospective compressed-air
workers (CAWs). The purpose of this screening procedure is to vet
prospective CAWs with medical conditions (e.g., deep vein thrombosis,
poor vascular circulation, and muscle cramping) that could be
aggravated by sitting in a cramped space (e.g., a man-lock) for
extended periods, or by exposure to elevated pressures and compressed
gas mixtures. A transportable recompression chamber (shuttle) is
available to extract workers from the hyperbaric working chamber for
emergency evacuation and medical treatment; the shuttle attaches to the
topside medical lock, which is a large recompression chamber. The
applicant believes that the procedures included in the HOM provide safe
work conditions when interventions are necessary, including
interventions above 50 p.s.i.g.
OSHA has comprehensively reviewed the project-specific HOM and has
determined that the safety and health instructions and measures it
specifies are appropriate, conform with the conditions in the variance,
and adequately protect the safety and health of the CAWs.
C. 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
[[Page 34890]]
appropriate).\3\ The applicant asserts decompression protocols using
the 1992 French Decompression Tables for air or oxygen as specified by
the SOTC 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
compressed-air worker (CAWs) after they exit the hyperbaric conditions
in the working chamber.
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\3\ 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. McNally/ASI Marine 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 (competent person), 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.
D. 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 (see footnote 12 in this notice discussing a 1985 NIOSH report on
DCI).
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.\4\ 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 (a competent person experienced and
trained in hyperbaric operations, procedures, and safety) 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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\4\ 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 percent 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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E. 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 the 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-
[[Page 34891]]
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
document.
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(e)(5)
McNally has developed, and proposed to implement, effective
alternative measures to the prohibition of using compressed air under
hyperbaric conditions exceeding 50 p.s.i. The proposed alternative
measures include use of engineering and administrative controls of the
hazards associated with work performed in compressed-air conditions
exceeding 50 p.s.i. while engaged in the construction of a subaqueous
tunnel using advance shielded mechanical-excavation techniques in
conjunction with the TBM. Prior to conducting interventions in the
TBM's pressurized working chamber, McNally/ASI Marine halts tunnel
excavation and prepares the machine and crew to conduct the
interventions. Interventions involve inspection, maintenance, or repair
of the mechanical-excavation components located in the working chamber.
B. 29 CFR 1926.803(f)(1)
McNally/ASI Marine 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 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 (competent person), 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) McNally/ASI Marine 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 it 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).\5\ 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 percent compared
to a previous incidence rate of 0.14 percent. 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.
---------------------------------------------------------------------------
\5\ Anderson HL (2002). Decompression sickness during
construction of the Great Belt tunnel, Denmark. Undersea and
Hyperbaric Medicine, 29(3), pp. 172-188.
---------------------------------------------------------------------------
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.\6\
---------------------------------------------------------------------------
\6\ 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).
---------------------------------------------------------------------------
OSHA's experience with the other previous tunneling permanent
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 \7\ that either granted variances
(Nevada, Oregon and Washington) \8\ or promulgated a new standard
(California) \9\ for hyperbaric exposures occurring during similar
subaqueous tunnel-construction work, provide additional evidence of the
effectiveness of this alternative procedure.
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\7\ 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 Plans.'' Occupational safety and health standards developed
by State Plans 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).
\8\ 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).
\9\ 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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C. 29 CFR 1926.803(g)(1)(iii)
McNally/ASI Marine 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.
[[Page 34892]]
In reaching this preliminary conclusion, OSHA again notes the
experience of previous nearly identical tunneling variances, the
experiences of State Plans, and a review of the literature and other
information noted earlier.
D. 29 CFR 1926.803(g)(1)(xvii)
McNally/ASI Marine 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 tunneling
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
(e)(5), (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 McNally/ASI Marine's CAWs to perform interventions in
hyperbaric conditions not exceeding 58 p.s.i.g. during the SOTC
Project, subject to the conditions that follow in this document. This
interim order will remain in effect until completion of the SOTC
Project or until the agency modifies or revokes the interim order or
makes a decision on McNally/ASI Marine's application for a permanent
variance. During the period starting with the publication of this
notice until completion of the SOTC Project, or until the agency
modifies or revokes the interim order or makes a decision on its
application for a permanent variance, the applicant 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
(hereafter, the standard) that:
1. Prohibit exposure to pressure greater than 50 p.s.i. (29 CFR
1926.803(e)(5));
2. 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));
3. Require the use of automated operational controls (29 CFR
1926.803(g)(1)(iii)); and
4. Require the use of a special decompression chamber (29 CFR
1926.803(g)(1)(xvii)).
In order to avail itself of the interim order, McNally/ASI Marine
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
McNally/ASI Marine's completion of the SOTC 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 approving or rejecting the request
for 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(e)(5), (f)(1), (g)(1)(iii), and (g)(1)(xvii) and provides
additional detail regarding the proposed conditions that form the basis
of McNally/ASI Marine's application for an interim order and for a
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 McNally/ASI Marine, McNally/ASI
Marine'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 McNally/ASI Marine 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) \10\ 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 instance, if OSHA were to grant a
permanent variance, it would apply to only the applicant, McNally/ASI
Marine and only the SOTC Project. As a result, it is important to
understand that if OSHA were to grant McNally/ASI Marine a permanent
variance, it would not apply to any other employers, such as other
joint ventures the applicant may undertake in the future.
---------------------------------------------------------------------------
\10\ 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 SOTC 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 serves 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,
[[Page 34893]]
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 an HOM specific to the SOTC 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 McNally/ASI Marine 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 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, McNally/ASI Marine 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 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
question on the form) are:
[[Page 34894]]
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.\11\
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\11\ 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; (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 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 Cleveland Ohio OSHA Area
Office within 15 working days should the applicant need to revise the
HOM to accommodate changes in its compressed-air operations that affect
McNally/ASI Marine's ability to comply with the conditions of the
proposed permanent variance; and (6) provide OTPCA and the Cleveland
Ohio Area Office, at the end of the project, with a report evaluating
the effectiveness of the decompression tables.
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 if it ceases to do business, has a new address or location
for the main office, or transfers 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 proposed permanent variance, thereby ensuring the safety
of workers involved in performing the 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 McNally/ASI Marine for the SOTC Project. These conditions
specify the alternative means of compliance with the requirements of
paragraphs 29 CFR 1926.803(e)(5), (f)(1), (g)(1)(iii), and
(g)(1)(xvii). In addition, these conditions are specific to the
alternative means of compliance with the requirements of paragraphs 29
CFR 1926.803 (e)(5), (f)(1), (g)(1)(iii), and (g)(1)(xvii) that OSHA is
proposing for McNally/ASI Marine'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.\12\
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\12\ 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
McNally/ASI Marine 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 McNally/ASI Marine stops the tunnel-boring work, pressurizes
the working chamber, and the CAWs either
[[Page 34895]]
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 variance apply only to work:
1. That occurs in conjunction with construction of the SOTC
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(e)(5), (f)(1), (g)(1)(iii), and (g)(1)(xvii).
B. Duration
The interim order granted to McNally/ASI Marine will remain in
effect until McNally/ASI Marine completes the SOTC Project, OSHA
modifies or revokes this interim order, or OSHA grants McNally/ASI's
request for a permanent variance. The proposed permanent variance, if
granted, would remain in effect until the completion of McNally/ASI's
SOTC 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--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
McNally/ASI Marine'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 50 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.\13\
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\13\ 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).\14\
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\14\ 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>
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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 Micro 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.\15\
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\15\ 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 McNally/ASI Marine
for working in compressed air during the SOTC 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 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.\16\
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\16\ Adapted from 29 CFR 1926.32(m).
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[[Page 34896]]
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. McNally/ASI Marine would have to adhere to the project-specific
HOM submitted to OSHA as part of the application (see OSHA-2025-0004-
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. McNally/ASI Marine 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. McNally/ASI Marine 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. McNally/ASI Marine would have to ensure that there are no
exposures to pressures greater than 58 p.s.i.g.
5. McNally/ASI Marine would have to ensure that air or oxygen is
the only breathing gas in the working chamber.
6. McNally/ASI Marine 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. McNally/ASI Marine would have to equip man-locks used by
employees with an air or oxygen delivery system, as specified by the
HOM, for the project. McNally/ASI Marine would be required not to store
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, McNally/ASI Marine would have to
maintain an adequate fire-suppression system approved for hyperbaric
work areas.
10. McNally/ASI Marine 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 \17\ indicates are essential
to prevent injury or illness.
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\17\ See ANSI/AIHA Z10-2012, American National Standard for
Occupational Health and Safety Management Systems, for reference.
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11. McNally/ASI Marine 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. McNally/ASI Marine 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
McNally/ASI Marine 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
McNally/ASI Marine 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)(2)(b) of this
proposed condition periodically and as necessary (e.g., after making
changes to its hyperbaric operations).
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 Cleveland Ohio Area Office before the
training takes place.
H. Inspections, Tests, and Accident Prevention
1. McNally/ASI Marine 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. McNally/ASI Marine 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 job.
[[Page 34897]]
I. Compression and Decompression
McNally/ASI Marine 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,
McNally/ASI Marine 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,
McNally/ASI Marine would have to:
(a) Notify the OTPCA and the Cleveland, Ohio 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 Cleveland Ohio Area Office within
15 working days of the incident that McNally/ASI Marine 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 Cleveland Ohio Area Office within 15
working days and in writing, of any change in the compressed-air
operations that affects McNally/ASI Marine's ability to comply with the
proposed conditions specified herein.
(d) Upon completion of the SOTC 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 Cleveland Ohio
Area Office.
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 Cleveland Ohio 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 variance.
2. OSHA would have to approve the transfer of the proposed
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(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. 2025-13889 Filed 7-23-25; 8:45 am]
BILLING CODE 4510-26-P
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