# Malonaldehyde — workplace exposure limit

For Malonaldehyde, niosh rel, as stated is Ca See Appendix A See Appendix C (Aldehydes); cas no. is 542-78-9, verified against its source on 2026-09-08.

- **Substance:** Malonaldehyde _(verified: appears in its own passage below)_
- **CAS No.:** 542-78-9 _(verified: appears in its own passage below)_
- **NIOSH REL, as stated:** Ca See Appendix A See Appendix C (Aldehydes) _(verified: appears in the quote below)_

## What the source says

> NIOSH REL Ca See Appendix A See Appendix C (Aldehydes)

## 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 - Malonaldehyde

### CAS No.

> CAS No. 542-78-9

## Source

- https://www.cdc.gov/niosh/npg/npgd0377.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/).