# Chromic acid and chromates — workplace exposure limit

For Chromic acid and chromates, niosh rel (mg/m³) is TWA 0.0002; cas no. is 1333-82-0 (CrO3), verified against its source on 2026-09-08.

- **Substance:** Chromic acid and chromates _(verified: appears in its own passage below)_
- **CAS No.:** 1333-82-0 (CrO3) _(verified: appears in its own passage below)_
- **NIOSH REL (mg/m³):** TWA 0.0002 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL (as Cr): Ca TWA 0.0002 mg/m3 (8-hours)

## 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 - Chromic acid and chromates

### CAS No.

> CAS No. 1333-82-0 (CrO3)

## Source

- https://www.cdc.gov/niosh/npg/npgd0138.html

Last verified: 2026-09-08. Review by: 2027-09-08.
Part of [US workplace chemical exposure limits: federal OSHA, Cal/OSHA and NIOSH, side by side](https://referencesource.org/workplace-exposure-limits/).