1910.134(i)(1)(ii): Grade D Breathing Air
Employers must make sure compressed breathing air meets at least Grade D under ANSI/CGA G-7.1-1989, including oxygen of 19.5-23.5%, condensed hydrocarbons of 5 milligrams per cubic meter or less, carbon monoxide of 10 ppm or less, carbon dioxide of 1,000 ppm or less, and no noticeable odor.
Key takeaways
- 1910.134(i)(1)(ii) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart I).
- OSHA cited it 31 times in the last 3 years, in 31 inspections, with $82,055 in current penalties.
- 2 deaths are linked to inspections that cited this rule.
- Most citations: IL (9), NJ (4), VA (3).
- 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)(1)(ii) is one requirement inside 1910.134 Respiratory protection, an OSHA general industry standard (Part 1910, Subpart I). It includes 5 sub-paragraphs. 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
(ii) Compressed breathing air shall meet at least the requirements for Grade D breathing air described in ANSI/Compressed Gas Association Commodity Specification for Air, G-7.1-1989, to include: 31 citations
(A) Oxygen content (v/v) of 19.5-23.5%; Open (i)(1)(ii)(a) 2 citations
(B) Hydrocarbon (condensed) content of 5 milligrams per cubic meter of air or less;
(C) Carbon monoxide (CO) content of 10 ppm or less;
(D) Carbon dioxide content of 1,000 ppm or less; and
(E) Lack of noticeable odor. 1 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)(1)(ii).
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
| Year | Citations |
|---|---|
| 2024 | 15 |
| 2025 | 9 |
| 2026 | 7 |
Top states: IL (9), NJ (4), VA (3), NC (2), KS (2)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| TEXTRON AVIATION INC | WICHITA, KS | $16,550 |
| HENKELS & MCCOY, INC. | YORK, PA | $16,550 |
| CABRAS MARINE CORPORATION | PITI, GU | $9,848 |
| RIGGINS COMPANY, L.C. | HAMPTON, VA | $7,690 |
| PACIFIC SHIPYARDS INTERNATIONAL, LLC | HONOLULU, HI | $6,347 |
Free toolbox talk
A 5-minute crew talk on 1910.134(i)(1)(ii), plus alerts when this rule changes. Free.
OSHA interpretation letters
- Clarifications for breathing air quality and use (2023-05-31)
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)(7) 30 citations
- 1910.134(i)(5)(iv) 24 citations
- 1910.134(i)(4)(i) 18 citations
- 1910.134(i)(8) 7 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
What grade must compressed breathing air meet?
At least Grade D breathing air as described in ANSI/Compressed Gas Association G-7.1-1989.
What is the carbon monoxide limit?
10 ppm or less.
What oxygen range is required?
19.5-23.5% oxygen content.
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 2026-10-21
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.