# 2025-23804: OSHA Bends Rules for Cleveland's Deep Tunnel Diggers

2025-23804, McNally Tunneling Corp./ASI Marine Southerly Tunnel and Consolidation Project: Grant of Permanent Variance, is a Federal Register notice from Labor Department, Occupational Safety and Health Administration published 2025-12-29, effective 2025-12-29 (as of 2026-06-08).

- Canonical: https://policyrisk.com/federal-register/2025-23804
- As of: 2026-06-08
- Plain-text twin of the page above; the HTML and this file carry the same facts.

## Facts
- Document number: 2025-23804
- Title: McNally Tunneling Corp./ASI Marine Southerly Tunnel and Consolidation Project: Grant of Permanent Variance
- Type: Notice
- Agencies: Labor Department; Occupational Safety and Health Administration
- Citation: 90 FR 60752
- Published: 2025-12-29
- Effective: 2025-12-29
- Comments close: not stated
- Significant: no
- Touches household money: no
- Regulation identifier numbers: none
- Last updated: 2026-06-08

## In one line

OSHA Bends Rules for Cleveland's Deep Tunnel Diggers

## Summary

OSHA gave McNally Tunneling Corp./ASI Marine a permanent green light to work in compressed-air conditions for their Southerly Tunnel project in Cleveland. This special permission starts December 29, 2025, and lasts until the project wraps up or OSHA changes its mind. It means McNally/ASI Marine can keep digging safely with some relaxed rules, helping the job move along without costly delays.

## Abstract

In this notice, OSHA grants a permanent variance to McNally Tunneling Corp./ASI Marine (McNally/ASI Marine) related to work in compressed-air environments.

## Effects PRIA read

- Allowed Compressed-Air Pressure Raised: mixed, medium. OSHA gave McNally/ASI Marine permission to expose workers to compressed-air pressures up to 58 p.s.i.g. during interventions in the TBM for the Southerly Tunnel project. This permission is effective December 29, 2025 and lasts until the project is finished or OSHA modifies or revokes the variance.
- Use of 1992 French Decompression Tables: benefit, medium. McNally/ASI Marine may use the 1992 French Decompression Tables (including oxygen-assisted staged decompression) instead of OSHA's Appendix A decompression tables for workers on the Southerly Tunnel project. The company says the alternative can reduce decompression time by about 33 percent and lowe…
- Manual Staged Decompression Allowed: benefit, medium. Instead of requiring automated continuous decompression controllers, the variance allows staged (manual) decompression under the direct control of trained man-lock attendants and oversight by a hyperbaric supervisor and certified physician for the Southerly Tunnel project. OSHA found this manual st…
- Man-Locks Replace Special Chamber: benefit, low. Because of TBM space limits, the variance allows use of the TBM's twin man-locks and the staging chamber instead of adding a separate special decompression chamber for the Southerly Tunnel project. The man-locks and staging chamber must accommodate the maximum crew of three and allow movement durin…
- Variance Limited to McNally/ASI Southerly Project: mixed, low. The permanent variance applies only to McNally Tunneling Corp./ASI Marine and only to the remainder of construction work on the Southerly Tunnel and Consolidation Project in Cleveland. It does not apply to other McNally/ASI Marine tunneling projects or other employers.

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## Sources
- [2025-23804 on federalregister.gov](https://www.federalregister.gov/documents/2025/12/29/2025-23804/mcnally-tunneling-corpasi-marine-southerly-tunnel-and-consolidation-project-grant-of-permanent)
- [2025-23804 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2025-12-29/pdf/2025-23804.pdf)

## Related
- [Previous: 2025-23803, Certain Welded Large Diameter Line Pipe from Japan](https://policyrisk.com/federal-register/2025-23803)
- [Next: 2025-23805, CBNA/Halmar Joint Venture; Potomac River Tunnel Project; Grant of Permanent Var…](https://policyrisk.com/federal-register/2025-23805)
- [All Federal Register documents](https://policyrisk.com/federal-register)

Source: PRIA, https://policyrisk.com/federal-register/2025-23804 (as of 2026-06-08).