1910.1000(b)(2): Ceiling Limits for Air Contaminants
Employers must keep a worker's exposure to any substance in Table Z-2 from going over its acceptable ceiling concentration at any time during an 8-hour shift. The only exception is a peak above the ceiling that stays within the maximum duration and concentration listed in the table for that substance.
Key takeaways
- 1910.1000(b)(2) is part of OSHA's general industry standards (29 CFR Part 1910).
- OSHA cited it 9 times in the last 3 years, in 9 inspections, with $373,879 in current penalties.
- 2 deaths are linked to inspections that cited this rule.
- Related part: 1910.1000(b) Table Z-2 (12 citations).
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In this article
What this rule covers
29 CFR 1910.1000(b)(2) ("Acceptable ceiling concentrations") is one requirement inside 1910.1000 Air contaminants, an OSHA general industry standard (Part 1910). 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
(2) Acceptable ceiling concentrations. An employee's exposure to a substance listed in Table Z-2 shall not exceed at any time during an 8-hour shift the acceptable ceiling concentration limit given for the substance in the table, except for a time period, and up to a concentration not exceeding the maximum duration and concentration allowed in the column under “acceptable maximum peak above the acceptable ceiling concentration for an 8-hour shift.” 9 citations
Source: eCFR, text current as of 2026-10-15. Read all of 1910.1000.
Export the list: 9 inspections cited 1910.1000(b)(2) in the last 3 years, with employer, location, penalty and date.
Purple Belt, $59/moInjuries linked to this rule
2 deaths are linked to inspections where OSHA cited 1910.1000(b)(2).
At 3:22 p.m. on May 29, 2024, Employee #1 was attempting to rescue a fellow employee who had been overcome by hydrogen sulfide (H2S) gas in an underground pump house. Prior to this incident, multiple coworkers had been working in the pump house and were…
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
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OSHA interpretation letters
None exist. OSHA has not published a letter of interpretation for 1910.1000(b)(2).
Related parts of this rule
- 1910.1000(b) Table Z-2 12 citations
- 1910.1000(b)(1) 8-hour time weighted averages 3 citations
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Frequently asked questions
What is a ceiling concentration?
A limit in Table Z-2 that a worker's exposure must not exceed at any time during an 8-hour shift.
Can exposure ever go above the ceiling?
Only for a time and concentration not exceeding the maximum peak values listed in Table Z-2.
Which substances does this cover?
Substances listed in Table Z-2.
About this page
Sources
- 29 CFR 1910.1000 (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 2026-11-06
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.