# Osmium tetroxide (as Os) — US workplace chemical exposure limits: federal OSHA vs Cal/OSHA, side by side

For Osmium tetroxide (as Os), cas no. is 20816-12-0; pel (mg/m³) is 0.002, verified against its source on 2026-08-05.

- **Substance:** Osmium tetroxide (as Os)
- **CAS No.:** 20816-12-0
- **PEL (mg/m³):** 0.002

## What the source says

> Osmium tetroxide (as Os) | 20816-12-0 | - | 0.002 | - |

## Source

- https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1

Last verified: 2026-08-05. Review by: 2027-08-05.
Part of [US workplace chemical exposure limits: federal OSHA vs Cal/OSHA, side by side](https://referencesource.org/workplace-exposure-limits/).