# Manganese compounds and fume (as Mn) — workplace exposure limit

For Manganese compounds and fume (as Mn), niosh rel (mg/m³) is TWA 1; cas no. is 7439-96-5 (metal), verified against its source on 2026-09-08.

- **Substance:** Manganese compounds and fume (as Mn) _(verified: appears in its own passage below)_
- **CAS No.:** 7439-96-5 (metal) _(verified: appears in its own passage below)_
- **NIOSH REL (mg/m³):** TWA 1 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL TWA 1 mg/m3 ST 3 mg/m3

## 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 - Manganese compounds and fume (as Mn)

### CAS No.

> CAS No. 7439-96-5 (metal)

## Source

- https://www.cdc.gov/niosh/npg/npgd0379.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/).