# Asbestos — workplace exposure limit

For Asbestos, niosh rel, as stated is Ca See Appendix A See Appendix C; cas no. is 1332-21-4, verified against its source on 2026-09-08.

- **Substance:** Asbestos _(verified: appears in its own passage below)_
- **CAS No.:** 1332-21-4 _(verified: appears in its own passage below)_
- **NIOSH REL, as stated:** Ca See Appendix A See Appendix C _(verified: appears in the quote below)_

## What the source says

> NIOSH REL Ca See Appendix A See Appendix C

## 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 - Asbestos

### CAS No.

> CAS No. 1332-21-4

## Source

- https://www.cdc.gov/niosh/npg/npgd0041.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/).