---
type: threshold
id: osmium-tetroxide-as-os-2
asset: workplace-exposure-limits
title: "Osmium tetroxide, as Os — US workplace chemical exposure limits: federal OSHA vs Cal/OSHA, side by side"
sources:
  - https://www.dir.ca.gov/title8/5155.html
source_quote: "20816120 | | Osmium tetroxide, as Os | 0.0002 | 0.002 | | 0.0006 | 0.006"
generated: true
harvested: 2026-08-05
stale_after: 2027-08-05
substance: "Osmium tetroxide, as Os"
pel_ppm: "0.0002"
pel_mgm3: "0.002"
stel_ppm: "0.0006"
stel_mgm3: "0.006"
verified: true
---
**Substance:** Osmium tetroxide, as Os

**PEL (ppm):** 0.0002

**PEL (mg/m³):** 0.002

**STEL (ppm):** 0.0006

**STEL (mg/m³):** 0.006

> 20816120 | | Osmium tetroxide, as Os | 0.0002 | 0.002 | | 0.0006 | 0.006

Source: <https://www.dir.ca.gov/title8/5155.html>