# Phenylhydrazine — US workplace chemical exposure limits: federal OSHA vs Cal/OSHA, side by side

For Phenylhydrazine, cas no. is 100-63-0; pel (ppm) is 5; pel (mg/m³) is 22, verified against its source on 2026-08-05.

- **Substance:** Phenylhydrazine
- **CAS No.:** 100-63-0
- **PEL (ppm):** 5
- **PEL (mg/m³):** 22

## What the source says

> Phenylhydrazine | 100-63-0 | 5 | 22 | X |

## Sources disagree

More than one authority states this, and they do not state the same
thing. Both are reproduced with the source each came from.

### PEL (mg/m³)

osha.gov says pel (mg/m³) is **22**, as of 2026-08-05.

> Phenylhydrazine | 100-63-0 | 5 | 22 | X |

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

dir.ca.gov says pel (mg/m³) is **20**, as of 2026-08-05.

> 100630 | S | Phenylhydrazine | 5 | 20 | | 10 | 45

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


## Source

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

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