1910.272(g)(1)(iii): Testing the Air in Grain Bins, Silos and Tanks
Employers must test the atmosphere in a bin, silo or tank for combustible gases, vapors and toxic agents when there is reason to believe they are present, and for oxygen unless there is continuous natural or forced-air ventilation. If oxygen is below 19.5%, combustible gas exceeds 10% of the lower flammable limit, or toxic agents exceed limits, ventilation is required, and respirators if ventilation cannot fix it.
Key takeaways
- 1910.272(g)(1)(iii) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart R).
- OSHA cited it 19 times in the last 3 years, in 19 inspections, with $53,155 in current penalties.
- 2 deaths are linked to inspections that cited this rule.
- Most citations: IL (5), MO (3), OH (2).
- Related part: 1910.272(g) Entry into grain storage structures (110 citations).
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In this article
What this rule covers
29 CFR 1910.272(g)(1)(iii) is one requirement inside 1910.272 Grain handling facilities, an OSHA general industry standard (Part 1910, Subpart R). It includes 2 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
(iii) The atmosphere within a bin, silo, or tank shall be tested for the presence of combustible gases, vapors, and toxic agents when the employer has reason to believe they may be present. Additionally, the atmosphere within a bin, silo, or tank shall be tested for oxygen content unless there is continuous natural air movement or continuous forced-air ventilation before and during the period employees are inside. If the oxygen level is less than 19.5%, or if combustible gas or vapor is detected in excess of 10% of the lower flammable limit, or if toxic agents are present in excess of the ceiling values listed in subpart Z of 29 CFR part 1910, or if toxic agents are present in concentrations that will cause health effects which prevent employees from effecting self-rescue or communication to obtain assistance, the following provisions apply. 19 citations
(A) Ventilation shall be provided until the unsafe condition or conditions are eliminated, and the ventilation shall be continued as long as there is a possibility of recurrence of the unsafe condition while the bin, silo, or tank is occupied by employees.
(B) If toxicity or oxygen deficiency cannot be eliminated by ventilation, employees entering the bin, silo, or tank shall wear an appropriate respirator. Respirator use shall be in accordance with the requirements of § 1910.134.
Source: eCFR, text current as of 2026-10-15. Read all of 1910.272.
Injuries linked to this rule
2 deaths are linked to inspections where OSHA cited 1910.272(g)(1)(iii).
At approximately 7:00 p.m. on February 24, 2025, Employee #1 entered a grain binwhile operating an auger. While inside the bin, the employee was caught in the sweep auger and sustained fatal injuries.
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 |
|---|---|
| 2023 | 2 |
| 2024 | 7 |
| 2025 | 4 |
| 2026 | 6 |
Top states: IL (5), MO (3), OH (2), KY (1), KS (1)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| BLACK RIVER COMMODITIES, LLC | POCAHONTAS, AR | $16,134 |
| MFA INC | HAMILTON, MO | $16,131 |
| LITTLEJOHN GRAIN, INC. | WESTFIELD, IL | $10,000 |
| 66656 - OBRYAN COMPOSTING LLC | SAINT JOSEPH, KY | $3,920 |
| FARMERS CO-OPERATIVE | PILGER, NE | $3,387 |
Free toolbox talk
A 5-minute crew talk on 1910.272(g)(1)(iii), plus alerts when this rule changes. Free.
OSHA interpretation letters
None exist. OSHA has not published a letter of interpretation for 1910.272(g)(1)(iii).
Related parts of this rule
- 1910.272(g) Entry into grain storage structures 110 citations
- 1910.272(g)(1) 89 citations
- 1910.272(g)(1)(ii) 41 citations
- 1910.272(g)(1)(i) 22 citations
- 1910.272(g)(4) 7 citations
- 1910.272(g)(3) 5 citations
- 1910.272(g)(2) 5 citations
- 1910.272(g)(5) 4 citations
- 1910.272(g)(6)
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Trainers on Black Belt Safety: Marc Harvey, Dana Reyes
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Frequently asked questions
When must oxygen be tested?
Unless there is continuous natural air movement or continuous forced-air ventilation before and during the time employees are inside.
What readings require action?
Oxygen less than 19.5%, combustible gas or vapor in excess of 10% of the lower flammable limit, or toxic agents above subpart Z ceiling values or at levels that prevent self-rescue or calling for help.
What if ventilation cannot fix it?
Employees entering must wear an appropriate respirator used under 1910.134.
About this page
Sources
- 29 CFR 1910.272 (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.