1910.134(i)(8): Breathing Air Couplings Must Not Fit Other Lines
Employers must make sure breathing air couplings cannot connect to outlets for non-breathable worksite air or other gas systems. No asphyxiating substance may be put into breathing air lines.
Key takeaways
- 1910.134(i)(8) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart I).
- OSHA cited it 7 times in the last 3 years, in 7 inspections, with $56,473 in current penalties.
- 2 deaths are linked to inspections that cited this rule.
- Related part: 1910.134(i) Breathing air quality and use (149 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1910.134(i)(8) is one requirement inside 1910.134 Respiratory protection, an OSHA general industry standard (Part 1910, Subpart I). The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
(8) The employer shall ensure that breathing air couplings are incompatible with outlets for nonrespirable worksite air or other gas systems. No asphyxiating substance shall be introduced into breathing air lines. 7 citations
Source: eCFR, text current as of 2026-10-15. Read all of 1910.134.
Injuries linked to this rule
2 deaths are linked to inspections where OSHA cited 1910.134(i)(8).
At 11:43 a.m. on February 24, 2025, Employee #1 was spray painting aircraft parts while wearing a supplied air respirator. Nitrogen back flowed into the breathing air system, displacing oxygen and causing the employee to be asphyxiated. Employee #1 was fatally injured.
Full case list with employer, penalty, filters and download is part of OSHA Data (Purple Belt).
Unlock with Purple BeltWhere and how often it was cited
Free toolbox talk
A 5-minute crew talk on 1910.134(i)(8), plus alerts when this rule changes. Free.
OSHA interpretation letters
- Couplings used in supplied air respirator systems. (1986-04-24)
Related parts of this rule
- 1910.134(i) Breathing air quality and use 149 citations
- 1910.134(i)(4) 43 citations
- 1910.134(i)(1) 34 citations
- 1910.134(i)(5) 34 citations
- 1910.134(i)(1)(ii) 31 citations
- 1910.134(i)(7) 30 citations
- 1910.134(i)(5)(iv) 24 citations
- 1910.134(i)(4)(i) 18 citations
- 1910.134(i)(4)(ii) 3 citations
- 1910.134(i)(5)(i) 3 citations
- 1910.134(i)(1)(ii)(A) 2 citations
- 1910.134(i)(1)(i)
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Frequently asked questions
Why must breathing air couplings be incompatible with other outlets?
So a respirator cannot be hooked up to non-breathable worksite air or another gas system.
Can anything else be put into breathing air lines?
No asphyxiating substance may be introduced into breathing air lines.
Who is responsible for this?
The employer must ensure it.
About this page
Sources
- 29 CFR 1910.134 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-22
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.