# Formaldehyde — workplace exposure limit

For Formaldehyde, niosh rel (ppm) is TWA 0.016; cas no. is 50-00-0, verified against its source on 2026-09-08.

- **Substance:** Formaldehyde _(verified: appears in its own passage below)_
- **CAS No.:** 50-00-0 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** TWA 0.016 _(verified: appears in the quote below)_
- **PEL (ppm):** 0.75 _(per dir.ca.gov, not stated by the source above)_
- **STEL (ppm):** 2 _(per dir.ca.gov, not stated by the source above)_

## What the source says

> NIOSH REL Ca TWA 0.016 ppm C 0.1 ppm [15-minute]

## 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 - Formaldehyde

### CAS No.

> CAS No. 50-00-0

## What osha.gov says

> Formaldehyde; see 1910.1048 | 50-00-0 | - | - | - |

Source: https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1

## What dir.ca.gov says

> 50000 | | Formaldehyde, see Section 5217 | 0.75 | -- | | 2 | --

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

## Source

- https://www.cdc.gov/niosh/npg/npgd0293.html
- https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
- https://www.dir.ca.gov/title8/5155.html

Last verified: 2026-09-08. Review by: 2027-08-05.
Part of [US workplace chemical exposure limits: federal OSHA, Cal/OSHA and NIOSH, side by side](https://referencesource.org/workplace-exposure-limits/).