# Sodium cyanide (as CN) — workplace exposure limit

For Sodium cyanide (as CN), niosh rel (ppm) is 4.7; niosh rel (mg/m³) is C 5; cas no. is 143-33-9, verified against its source on 2026-09-08.

- **Substance:** Sodium cyanide (as CN) _(verified: appears in its own passage below)_
- **CAS No.:** 143-33-9 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** 4.7 _(verified: appears in the quote below)_
- **NIOSH REL (mg/m³):** C 5 _(verified: appears in the quote below)_

## What the source says

> NIOSH REL C 5 mg/m3 (4.7 ppm) [10-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 - Sodium cyanide (as CN)

### CAS No.

> CAS No. 143-33-9

## Source

- https://www.cdc.gov/niosh/npg/npgd0562.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/).