Nitric acid — workplace exposure limit
What is the pel (ppm) for Nitric acid — workplace exposure limit?
For Nitric acid, pel (ppm) is 2; pel (mg/m³) is 5; cas no. is 7697-37-2, verified against its source on 2026-08-05.
Nitric acid | 7697-37-2 | 2 | 5 | - |
— osha.gov, retrieved 2026-08-05
2
The most of this substance workplace air may legally contain, averaged over an 8-hour shift — OSHA's permissible exposure limit (PEL), in parts per million, from the agency's own table row quoted below. Where federal OSHA and Cal/OSHA disagree, both limits are stated, each with its own agency's table row as evidence. NIOSH's number, where there is one, is shown separately: it is a recommended limit, not a legal one, and it is often the strictest of the three.
- Substance
- Nitric acid verified
- CAS No.
- 7697-37-2 verified
- PEL (ppm)
- 2 verified
- PEL (mg/m³)
- 5 verified
- STEL (ppm)
- 4 per dir.ca.gov
- STEL (mg/m³)
- 10 per dir.ca.gov
- NIOSH REL (ppm)
- TWA 2 per cdc.gov
- NIOSH REL (mg/m³)
- 5 per cdc.gov
What dir.ca.gov says
7697372 | | Nitric acid | 2 | 5 | | 4 | 10
— dir.ca.gov, retrieved 2026-08-05
What cdc.gov says
NIOSH REL TWA 2 ppm (5 mg/m3) ST 4 ppm (10 mg/m3)
— cdc.gov, retrieved 2026-09-08
Sources
- osha.govhttps://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
- dir.ca.govhttps://www.dir.ca.gov/title8/5155.html
- cdc.govhttps://www.cdc.gov/niosh/npg/npgd0447.html