83152 Federal Register / Vol. 88, No. 227 / Tuesday, November 28, 2023 / Notices 

1The 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. 

DEPARTMENT OF LABOR 

Occupational Safety and Health 

Administration 

[Docket No. OSHA–2023–0004] 

Traylor-Sundt Joint Venture: Grant of 

Permanent Variance 

AGENCY: Occupational Safety and Health 

Administration (OSHA), Labor. 

ACTION: Notice. 

SUMMARY: In this notice, OSHA grants a 

permanent variance to Traylor-Sundt 

Joint Venture (SUNDTJV) related to 

work in compressed-air environments. 

DATES: The permanent variance 

specified by this notice becomes 

effective on November 28, 2023 and 

shall remain in effect until the 

completion of the Integrated Pipeline 

Tunnel project or until modified or 

revoked by OSHA. 

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: meilinger.francis2@dol.gov. 

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) 693–2110; 

email: robinson.kevin@dol.gov. 

Copies of this Federal Register notice. 

Electronic copies of this Federal 

Register notice are available at http://

www.regulations.gov. This Federal 

Register notice, as well as news releases 

and other relevant information, also are 

available at OSHA’s web page at http:// 

www.osha.gov. 

SUPPLEMENTARY INFORMATION: 

I. Overview 

On April 20, 2022, Traylor Bros., Inc. 

(Traylor) submitted an application by 

letter to modify the permanent variance 

granted to Traylor on March 11, 2016 

(2016 Variance) (81 FR 12954), to 

include an additional employer, the 

Traylor-Sundt Joint Venture 

(SUNDTJV), which is a joint venture 

made up of two construction 

companies; Traylor and Sundt 

Construction, Inc. (Sundt). SUNDTJV 

was awarded the tunneling contract for 

the Integrated Pipeline Tunnel Project 

in Dallas, Texas (OSHA–2023–0004– 

0002). The Integrated Pipeline Tunnel 

Project includes two tunnels, the Cedar 

Creek Tunnel, and the Hollywood Lake 

Tunnel, which require two separate 

tunnel drives. SUNDTJV also requested 

an interim order while OSHA evaluates 

the application (OSHA–2023–0004– 

0003). Because the joint venture 

includes an additional employer not 

covered by the previously issued 

permanent variance, OSHA has 

evaluated the modification request as an 

application by SUNDTJV for a new 

permanent variance. This notice covers 

the Integrated Pipeline Tunnel Project 

only and is not applicable to future 

tunneling projects by Traylor, Sundt, or 

SUNDTJV. 

This notice addresses the application 

by SUNDTJV (the applicant) for a 

permanent variance and interim order 

from the provisions of the standard 

governing compressed air work 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 compressedair 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 

1926.803(g)(1)(iii) and (g)(1)(xvii), 

respectively). 

OSHA reviewed SUNDTJV’s 

application for the variance and interim 

order and determined that they were 

appropriately submitted in compliance 

with the applicable variance procedures 

in Section 6(d) of the Occupational 

Safety and Health Act of 1970 (OSH Act; 

29 U.S.C. 655) and OSHA’s regulations 

at 29 CFR 1905.11 (Variances and other 

relief under section 6(d)), including the 

requirement that the applicant inform 

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. 

OSHA reviewed the alternative 

procedures in SUNDTJV’s application 

and preliminarily determined that the 

applicant’s proposed alternatives on the 

whole, subject to the conditions in the 

request and imposed by the interim 

order, provide measures that are as safe 

and healthful as those required by the 

cited OSHA standards. On May 1, 2023, 

OSHA published a Federal Register 

notice announcing SUNDTJV’s 

application for permanent variance, 

stating the preliminary determination 

along with the basis of that 

determination, and granting the interim 

order (88 FR 26600). OSHA requested 

comments on each. 

OSHA did not receive any comments 

or other information disputing the 

preliminary determination that the 

alternatives were at least as safe as 

OSHA’s standard, nor any objections to 

OSHA granting a permanent variance. 

Accordingly, through this notice OSHA 

grants a permanent variance, subject to 

the conditions set out in this document. 

A. Background 

The information that follows about 

SUNDTJV, its methods, and the 

Integrated Pipeline Tunnel Project 

comes from the SUNDTJV variance 

application. 

SUNDTJV is a contractor for the 

Integrated Pipeline Tunnel Project (the 

project), that works on complex tunnel 

projects using innovations in tunnelexcavation methods. The applicant’s 

workers engage in the construction of 

tunnels using advanced shielded 

mechanical excavation techniques in 

conjunction with an earth pressure 

balance 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 working chamber) 

of the TBM. 

SUNDTJV 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, groundtreatment 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 


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2See the definition of ‘‘Affected employee or 

worker’’ in section VI.C of this Notice. 

3The previous tunnel construction variances 

allowed further deviation from OSHA standards by 

permitting employee exposures above 50 p.s.i., 

based on the composition of the soil and the 

amount of water that will be above the tunnel for 

various sections of this project. The current 

Continued 

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. 

SUNDTJV’s Hyperbaric Operations 

Manual (HOM) for the Integrated 

Pipeline Tunnel Project indicates that 

the maximum pressure to which it is 

likely to expose workers during project 

interventions for the Integrated Pipeline 

Tunnel Project is 58 p.s.i. Therefore, to 

work effectively, SUNDTJV must 

perform hyperbaric interventions in 

compressed air at pressures nearly 15% 

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. except in 

emergency’’ (see footnote 1). 

SUNDTJV employs specially trained 

personnel for the construction of the 

tunnel. To keep the machinery working 

effectively, SUNDTJV 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., 

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 manlocks and the working chamber are 

designed to accommodate three people, 

which is the maximum crew size 

allowed under the permanent 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. 

SUNDTJV 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 the caisson work regulated 

by the current OSHA compressed-air 

standard for construction at 29 CFR 

1926.803. 

In addition to the reduced exposures 

resulting from the innovations in 

tunnel-excavation methods, SUNDTJV 

asserts that innovations in hyperbaric 

medicine and technology improve the 

safety of decompression from 

hyperbaric exposures. These 

procedures, however, 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 SUNDTJV, 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. 

SUNDTJV contends that the 

alternative safety measures included in 

the application provide SUNDTJV’s 

workers with a place of employment 

that is at least as safe under its proposed 

alternatives as they would be under 

OSHA’s compressed-air standard for 

construction. SUNDTJV also provided 

OSHA a project-specific HOM, (OSHA– 

2023–0004–0004) 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 to support their 

assertions of equivalency in worker 

protection. 

OSHA included all of the above 

information in the Federal Register 

notice announcing SUNDTJV’s variance 

application and did not receive any 

comments disputing any of that 

information, including the safety 

assertions made by SUNDTJV in the 

variance application. 

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 

application. In addition, the applicant 

has certified that it informed its workers 

of their right to petition the Assistant 

Secretary of Labor for Occupational 

Safety and Health for a hearing on the 

variance application. 

III. 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 

(tunnel construction variances). 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 completion of the Anacostia 

River Tunnel in Washington, DC (80 FR 

50652 (August 20, 2015)); (2) Traylor JV 

for the completion of the Blue Plains 

Tunnel in Washington, DC (80 FR 16440 

(March 27, 2015)); (3) Tully/OHL USA 

Joint Venture for the completion of 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 completion of the Northeast 

Boundary Tunnel in Washington, DC 

(85 FR 27767, (May 11, 2020)); (5) 

McNally/Kiewit SST Joint Venture for 

the completion of the Shoreline Storage 

Tunnel Project in Cleveland, Ohio (88 

FR 15080, March 10, 2023); and (6) 

Traylor-Shea Joint Venture for the 

completion of the Alexandria 

RiverRenew Tunnel Project in 

Alexandria Virginia and Washington DC 

(88 FR 15080, March 10, 2023). OSHA 

also granted an interim order to Ballard 

Marine for the Suffolk County Outfall 

Tunnel project in West Babylon, New 

York (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.3 OSHA is not 


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permanent variance includes substantively the 

same safeguards as the variances that OSHA granted 

previously even though employees will not be 

exposed to pressures higher than 58 p.s.i.g. 

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). 

aware of any injuries or other safety 

issues that arose from work performed 

under these conditions in accordance 

with the previous variances. 

IV. Applicable OSHA Standard and the 

Relevant Variance 

A. Variance From Paragraph (e)(5) of 29 

CFR 1926.803, Prohibition of Exposure 

to Pressure Greater Than 50 p.s.i. 

The applicant states that it may 

perform hyperbaric interventions at 

pressures greater than 50 p.s.i. 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, groundtreatment 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. 

SUNDTJV 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. 

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, SUNDTJV has developed a 

project-specific HOM (OSHA–2023– 

0004–0004) 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 manlock 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 (a competent person 

experienced and trained in hyperbaric 

operations, procedures, and safety) and 

attending physician. In addition, 

procedures include medical screening 

and review of prospective compressedair 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 manlock) 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. 

or 50 p.s.i.g. 

OSHA comprehensively reviewed the 

project-specific HOM and determined 

that the safety and health instructions 

and measures it specifies are 

appropriate and adequately protect the 

safety and health of the CAWs. 

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 Integrated 

Pipeline 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 commits to 

following the decompression 

procedures described in that HOM, 

which requires SUNDTJV to follow the 

1992 French Decompression Tables to 

decompress CAWs after they exit the 

hyperbaric conditions in the working 

chamber. 

Depending on the maximum working 

pressure and exposure times, the 1992 

French Decompression Tables provide 

for air decompression with or without 

oxygen. SUNDTJV 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 


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5See, 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 compressedair 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.’’ 

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 

SUNDTJV seeks 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 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 

16 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.5

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 requires 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. 

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 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 manlock 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. 

V. Decision 

After reviewing the proposed 

alternatives, OSHA has determined that 

the applicant’s proposed alternatives on 

the whole, subject to the conditions in 

the request and imposed by this 

permanent variance, provide measures 

that are as safe and healthful as those 

required by the cited OSHA standards 

addressed in section IV of this notice. 

In addition, OSHA has determined 

that each of the following alternatives 

are at least as effective as the specified 

OSHA requirements: 

A. 29 CFR 1926.803(e)(5) 

The applicant 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 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, SUNDJV 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) 

The applicant 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 


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83156 Federal Register / Vol. 88, No. 227 / Tuesday, November 28, 2023 / Notices 

6Anderson HL (2002). Decompression sickness 

during construction of the Great Belt tunnel, 

Denmark. Undersea and Hyperbaric Medicine, 

29(3), pp. 172–188. 

7Le Pe ́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 

Docket ID. OSHA–2012–0036–0005). 

8Under 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). 

9These state variances are available in the docket 

for the 2015 Traylor JV variance: Docket ID. OSHA– 

2012–0035–0006 (Nevada), OSHA–2012–0035– 

0005 (Oregon), and OSHA–2012–0035–0004 

(Washington). 

10See California Code of Regulations, title 8, 

subchapter 7, group 26, article 154, available at 

http://www.dir.ca.gov/title8/sb7g26a154.html. 

11These state variances are available in the 

docket: Docket ID. OSHA–2012–0035–0006 

(Nevada), OSHA–2012–0035–0007 (Oregon), and 

OSHA–2012–0035–0008 (Washington). 

12See California Code of Regulations, title 8, 

subchapter 7, group 26, article 154, available at 

http://www.dir.ca.gov/title8/sb7g26a154.html. 

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. 

Prior to granting the six previous 

permanent variances to IHP JV, Traylor 

JV, Tully JV, Salini-Impregilo Joint 

Venture, Ballard, and Traylor TSJV, 

OSHA conducted a review of the 

scientific literature and concluded that 

the alternative decompression method 

(i.e., the 1992 French Decompression 

Tables) SUNDTJV proposed would be at 

least as safe as the decompression tables 

specified by OSHA when applied by 

trained medical personnel under the 

conditions imposed by the permanent 

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. Anderson 

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. 

Anderson 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. 

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

OSHA’s experience with the previous 

six 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 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. 

C. 29 CFR 1926.803(g)(1)(iii) 

The applicant 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 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. 

D. 29 CFR 1926.803(g)(1)(xvii) 

The applicant 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. 

Based on a review of available 

evidence, the experience of State Plans 

that either granted variances (Nevada, 

Oregon, and Washington) 11 or 

promulgated a new standard 

(California) 12 for hyperbaric exposures 

occurring during similar subaqueous 

tunnel-construction work, and the 

information provided in the applicant’s 

variance application, OSHA is granting 

the permanent variance. 

Pursuant to Section 6(d) of the 

Occupational Safety and Health Act of 

1970 (29 U.S.C. 655(d)), and based on 

the record discussed above, the agency 

finds that when SUNDTJV complies 

with the conditions of the following 

order, the working conditions of the 

workers are at least as safe and healthful 

as if it complied with the working 

conditions specified by paragraphs 

(e)(5), (f)(1), (g)(1)(iii), and (g)(1)(xvii) of 

29 CFR 1926.803. Therefore, SUNDTJV 

must: (1) comply with the conditions 

listed below under ‘‘Conditions 

Specified for the Permanent Variance’’ 

for the period between the date of this 

notice and completion of the Integrated 

Pipeline Tunnel Project; (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 

conditions, including the affected 

employees of other employers, using the 

same means it used to inform these 

employees of the application for a 


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permanent variance. Additionally, this 

order will remain in effect until one of 

the following conditions occurs: (1) 

completion of the Integrated Pipeline 

Tunnel Project; or (2) OSHA modifies or 

revokes this final order in accordance 

with 29 CFR 1905.13. 

VI. Description of the Specified 

Conditions for the Permanent Variance 

The conditions for the variance are set 

out in the Order at the end of this 

document. This section provides 

additional detail regarding the 

conditions in the Order. 

Condition A: Scope 

The scope of the permanent variance 

limits coverage to the work situations 

specified. Clearly defining the scope of 

the permanent variance provides 

SUNDTJV, SUNDTJV’s employees, 

potential future applicants, other 

stakeholders, the public, and OSHA 

with necessary information regarding 

the work situations in which the 

permanent variance applies. To the 

extent that SUNDTJV exceeds the 

defined scope of this variance, it will be 

required to comply with OSHA’s 

standards. This permanent variance 

applies only to the applicant, SUNDTJV, 

and only to the remainder of 

construction work on the Integrated 

Pipeline Tunnel Project. 

Condition B: List of Abbreviations 

Condition B defines abbreviations 

used in the 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 permanent 

variance. 

Condition C: Definitions 

The condition defines a series of 

terms, mostly technical terms, used in 

the 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 permanent 

variance. 

Condition D: Safety and Health 

Practices 

This condition requires the applicant 

to develop and submit to OSHA an 

HOM specific to the Integrated Pipeline 

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 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. The applicant has submitted 

the HOM and proof of compliance with 

ASME PVHO–1.2019. 

Additionally, the 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. 

Condition E: Communication 

This 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 

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. Availability of such reliable 

means of communications enables 

affected workers and support personnel 

to respond quickly and effectively to 

hazardous conditions or emergencies 

that may develop during TBM 

operations. 

Condition F: Worker Qualification and 

Training 

This condition requires the applicant 

to develop and implement an effective 

qualification and training program for 

affected workers. The 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 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 hyperbaricrelated 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. 

Condition G: Inspections, Tests, and 

Accident Prevention 

Condition G 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 

helps to ensure the safe operation and 

physical integrity of the equipment and 

work areas necessary to conduct 

hyperbaric operations. The condition 

also enhances worker safety by reducing 

the risk of hyperbaric-related 

emergencies. 

Paragraph (3) of this 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 provides 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. 


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13See 29 CFR 1904 Recording and Reporting 

Occupational Injuries and Illnesses (http:// 

www.osha.gov/pls/oshaweb/owadisp.show_

document?p_table=STANDARDS&p_id=9631); 

recordkeeping forms and instructions (http://

www.osha.gov/recordkeeping/RKform300pkgfillable-enabled.pdf); and OSHA Recordkeeping 

Handbook (http://www.osha.gov/recordkeeping/ 

handbook/index.html). 

Condition H: Compression and 

Decompression 

This condition requires 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 advisor. 

This proposed provision ensures 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 have an 

opportunity to acclimate prior to 

exposure to these hyperbaric conditions. 

OSHA believes this condition will 

prevent or reduce adverse reactions 

among CAWs to the effects of 

compression or decompression 

associated with the intervention work 

they perform in the TBM. 

Condition I: Recordkeeping 

Under OSHA’s 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 SUNDTJV 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 

• the task performed; 

• the composition of the gas mixture 

(e.g., air or oxygen); 

• an estimate of the CAW’s workload; 

• the maximum working pressure; 

• temperature in the work and 

decompression environments; 

• unusual occurrences, if any, during 

the task or decompression 

Q15 

• time of symptom onset; 

• duration between decompression 

and onset of symptoms 

Q16 

• type and duration of symptoms; 

• a medical summary of the illness or 

injury 

Q17 

• duration of the hyperbaric 

intervention; 

• possible contributing factors; 

• the number of prior interventions 

completed by the injured or ill CAW; 

and the pressure to which the CAW was 

exposed during those interventions.13

Condition J below adds additional 

reporting responsibilities, beyond those 

already required by the OSHA standard. 

The applicant is required to maintain 

records of specific factors associated 

with each hyperbaric intervention. The 

information gathered and recorded 

under Condition J, in concert with the 

information provided under Condition I 

(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, and 1904.8–.12), enables the 

applicant and OSHA to assess the 

effectiveness of the permanent variance 

in preventing DCI and other hyperbaricrelated effects. 

Condition J: Notifications 

Under the notifications 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 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 Area Office in 

Dallas, Texas within 15 working days 

should the applicant need to revise the 

HOM to accommodate changes in its 

compressed-air operations that affect 

SUNDTJVs ability to comply with the 

conditions of the permanent variance; 

and (6) provide OTPCA and the OSHA 

Area Office in Dallas, Texas, 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 exposurerelated (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 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 condition requires 

the applicant to notify OSHA no later 

than seven (7) days of having knowledge 

that it will cease to do business, has a 

new address or location for the main 

office, or transfers the operations 

covered by the 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 

permanent variance and expedite the 

agency’s administration and 

enforcement of the permanent variance. 

Stipulating that the 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 permanent variance, 


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14Adapted from 29 CFR 1926.32(f). 

15See 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 http://www.cdc.gov/niosh/ 

docket/archive/pdfs/NIOSH-254/compReg1996.pdf. 16Also see 29 CFR 1910.146(b). 

thereby ensuring the safety of workers 

involved in performing the operations 

covered by the permanent variance. 

VI. Order 

As of the effective date of this final 

order, OSHA is revoking the interim 

order granted to the employer on May 

1, 2023, and replacing it with a 

permanent variance order. Note that 

there are not any substantive changes in 

the conditions between the interim 

order and this final order. 

OSHA issues this final order 

authorizing SUNDTJV to comply with 

the following conditions instead of 

complying with the requirements of 29 

CFR 1926.803(e)(5), (f)(1), (g)(1)(iii), and 

(g)(1)(xvii). These conditions are: 

A. Scope 

The permanent variance applies only 

when SUNDTJV 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 permanent variance applies only 

to work: 

1. That occurs in conjunction with 

construction of the Integrated Pipeline 

Tunnel Project, a tunnel constructed 

using advanced shielded mechanicalexcavation 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). 

4. This order will remain in effect 

until one of the following conditions 

occurs: (1) completion of the Integrated 

Pipeline Tunnel Project; or (2) OSHA 

modifies or revokes this final order in 

accordance with 29 CFR 1905.13. 

B. List of Abbreviations 

Abbreviations used throughout this 

permanent variance includes 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 

C. Definitions 

The following definitions apply to 

this permanent variance, SUNDTJV’s 

project-specific HOM, and all work 

carried out under the conditions of this 

permanent variance. 

1. Affected employee or worker—an 

employee or worker who is affected by 

the conditions of this 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 

58 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

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

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 (O2) 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

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 SUNDTJV for working in compressed 

air during the Integrated Pipeline 

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 

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.—pounds per square inch, a 

common unit of measurement of 

pressure; a pressure given in p.s.i. 

corresponds to absolute pressure. 

17. 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. 

18. 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 


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17Adapted from 29 CFR 1926.32(m). 

18See ANSI/AIHA Z10–2012, American National 

Standard for Occupational Health and Safety 

Management Systems, for reference. 

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 p.s.i.g. 

19. 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

20. Working chamber—an enclosed 

space in the TBM in which CAWs 

perform interventions, and which is 

accessible only through a man-lock. 

D. Safety and Health Practices 

1. SUNDTJV must implement the 

project-specific HOM submitted to 

OSHA as part of the application (see 

OSHA–2023–0004–0004). The HOM 

provides the minimum requirements 

regarding expected safety and health 

hazards (including anticipated 

geological conditions) and hyperbaric 

exposures during the tunnelconstruction project. 

2. SUNDTJV has demonstrated 

through documentation in the HOM that 

the TBM, including its hyberbaric 

chambers, is in compliance with the 

requirements of ASME PVHO–1.2019 

(or more recent edition of Safety 

Standards for Pressure Vessels for 

Human Occupancy). SUNDTJV must 

notify OSHA before making any 

alterations to the TBM that would affect 

the PVHO certification. Any such 

alteration to the TBM would require 

recertification of compliance with 

ASME PVHO–1.2019 requirements and 

OSHA approval prior to use. 

3. SUNDTJV must 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. SUNDTJV must ensure that there 

are no exposures to pressures greater 

than 58 p.s.i.g. 

5. SUNDTJV must ensure that air or 

oxygen is the only breathing gas in the 

working chamber. 

6. SUNDTJV must 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. SUNDTJV must equip man-locks 

used by employees with an air or 

oxygen delivery system, as specified by 

the HOM for the project. SUNDTJV is 

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 must use 

flame-retardant personal protective 

equipment and clothing. 

9. In hyperbaric work areas, SUNDTJV 

must maintain an adequate firesuppression system approved for 

hyperbaric work areas. 

10. SUNDTJV must 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 must include all 

the job functions that the risk 

assessment 18 indicates are essential to 

prevent injury or illness. 

11. SUNDTJV must develop a set of 

checklists to guide compressed-air work 

and ensure that employees follow the 

procedures required by the permanent 

variance (including all procedures 

required by the HOM approved by 

OSHA for the project, which this 

permanent variance incorporates by 

reference). The checklists must include 

all steps and equipment functions that 

the risk assessment indicates are 

essential to prevent injury or illness 

during compressed-air work. 

12. SUNDTJV must 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. 

E. Communication 

1. Prior to beginning a shift, SUNDTJV 

must 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. SUNDTJV must provide a powerassisted means of communication 

among affected workers and support 

personnel in hyperbaric conditions 

where unassisted voice communication 

is inadequate. 

(a) SUNDTJV must use an 

independent power supply for powered 

communication systems, and these 

systems 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) SUNDTJV must test 

communication systems at the start of 

each shift and as necessary thereafter to 

ensure proper operation. 

F. Worker Qualifications and Training 

SUNDTJV must: 

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 must 

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 interventionrelated 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 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 Dallas Area Office before 

the training takes place. 

G. Inspections, Tests, and Accident 

Prevention 

1. SUNDTJV must 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 fireprevention and fire-suppression 


lotter on DSK11XQN23PROD with NOTICES1
Federal Register / Vol. 88, No. 227 / Tuesday, November 28, 2023 / Notices 83161 

19See 29 CFR 1904 (Recording and Reporting 

Occupational Injuries and Illnesses) (http://

www.osha.gov/pls/oshaweb/owadisp.show_

document?p_table=STANDARDS&p_id=9631); 

recordkeeping forms and instructions (http://

www.osha.gov/recordkeeping/RKform300pkgfillable-enabled.pdf); and the OSHA Recordkeeping 

Handbook (http://www.osha.gov/recordkeeping/ 

handbook/index.html). 

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. SUNDTJV must 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. 

H. Compression and Decompression 

SUNDTJV must consult with its 

attending physician concerning the 

need for special compression or 

decompression exposures appropriate 

for CAWs not acclimated to hyperbaric 

exposure. 

I. Recordkeeping 

In addition to completing OSHA Form 

301 Injury and Illness Incident Report 

and OSHA Form 300 Log of WorkRelated Injuries and Illnesses, SUNDTJV 

must 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. 

J. Notifications 

1. To assist OSHA in administering 

the conditions specified herein, 

SUNDTJV must: 

(a) Notify the OTPCA and the OSHA 

Area Office in Dallas, Texas at 

www.osha.gov/contactus/byoffice of any 

recordable injury, illness, or fatality (by 

submitting the completed OSHA Form 

301 Injuries and Illness Incident 

Report) 19 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 must 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 must 

include a root-cause determination, and 

the preventive and corrective actions 

identified and implemented. 

(b) Provide certification to the OTPCA 

and the OSHA Area Office in Dallas, 

Texas within 15 working days of the 

incident that SUNDTJV 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 

Area Office Dallas, Texas within 15 

working days and in writing, of any 

change in the compressed-air operations 

that affects SUNDTJV’s ability to 

comply with the conditions specified 

herein. 

(d) Upon completion of the Integrated 

Pipeline 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 

Area Office in Dallas, Texas. 

Note: The evaluation report must 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 WorkRelated 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 conditions specified herein, inform 

the OTPCA and the OSHA Area Office 

in Dallas, Texas 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 permanent variance by the same 

means required to inform them of its 

application for a permanent variance. 

(g) This permanent variance cannot be 

transferred to a successor company 

without OSHA approval. 

OSHA hereby grants a permanent 

variance to SUNDTJV to the provisions 

of 29 CFR 1926.803 outlined in this 

notice. 

VII. Authority and Signature 

James S. Frederick, Deputy 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. 

8–2020 (85 FR 58393, Sept. 18, 2020), 

and 29 CFR 1905.11. 

Signed at Washington, DC. 

James S. Frederick, 

Deputy Assistant Secretary of Labor for 

Occupational Safety and Health. 

[FR Doc. 2023–26179 Filed 11–27–23; 8:45 am] 

BILLING CODE 4510–26–P 

DEPARTMENT OF LABOR 

Veterans’ Employment and Training 

Service 

Agency Information Collection 

Activities; Comment Request: Federal 

Contractor Veterans’ Employment 

Report VETS–4212 

ACTION: Request for comments. 

SUMMARY: The Veterans’ Employment 

and Training Service (VETS) is 

announcing an opportunity for public 

comment on a collection of information 

by the agency. Under the Paperwork 

Reduction Act (PRA) of 1995, Federal 

agencies are required to publish notice 


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