Osmium tetroxide — workplace exposure limit
What is the niosh rel (ppm) for Osmium tetroxide — workplace exposure limit?
For Osmium tetroxide, niosh rel (ppm) is 0.0002; niosh rel (mg/m³) is TWA 0.002; cas no. is 20816-12-0, verified against its source on 2026-09-08.
NIOSH REL TWA 0.002 mg/m3 (0.0002 ppm) ST 0.006 mg/m3 (0.0006 ppm)
— cdc.gov, retrieved 2026-09-08
- Substance
- Osmium tetroxide verified
- CAS No.
- 20816-12-0 verified
- NIOSH REL (ppm)
- 0.0002 verified
- NIOSH REL (mg/m³)
- TWA 0.002 verified
- PEL (mg/m³)
- 0.002 per osha.gov
- PEL (ppm)
- 0.0002 per dir.ca.gov
- STEL (ppm)
- 0.0006 per dir.ca.gov
- STEL (mg/m³)
- 0.006 per dir.ca.gov
Where each value comes from
This source states these in separate places, so each value is shown with the passage that states it.
Substance
CDC - NIOSH Pocket Guide to Chemical Hazards - Osmium tetroxide
CAS No.
CAS No. 20816-12-0
— all from cdc.gov, retrieved 2026-09-08
What osha.gov says
Osmium tetroxide (as Os) | 20816-12-0 | - | 0.002 | - |
— osha.gov, retrieved 2026-08-05
What dir.ca.gov says
20816120 | | Osmium tetroxide, as Os | 0.0002 | 0.002 | | 0.0006 | 0.006
— dir.ca.gov, retrieved 2026-08-05
Sources
- cdc.govhttps://www.cdc.gov/niosh/npg/npgd0473.html
- osha.govhttps://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
- dir.ca.govhttps://www.dir.ca.gov/title8/5155.html