# Ethyl butyl ketone — workplace exposure limit

For Ethyl butyl ketone, niosh rel (ppm) is TWA 50; niosh rel (mg/m³) is 230; cas no. is 106-35-4, verified against its source on 2026-09-08.

- **Substance:** Ethyl butyl ketone _(verified: appears in its own passage below)_
- **CAS No.:** 106-35-4 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** TWA 50 _(verified: appears in the quote below)_
- **NIOSH REL (mg/m³):** 230 _(verified: appears in the quote below)_
- **PEL (ppm):** 50 _(per osha.gov, not stated by the source above)_
- **PEL (mg/m³):** 230 _(per osha.gov, not stated by the source above)_
- **STEL (ppm):** 75 _(per dir.ca.gov, not stated by the source above)_
- **STEL (mg/m³):** 345 _(per dir.ca.gov, not stated by the source above)_

## What the source says

> NIOSH REL TWA 50 ppm (230 mg/m3)

## 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 - Ethyl butyl ketone

### CAS No.

> CAS No. 106-35-4

## What osha.gov says

> Ethyl butyl ketone (3-Heptanone) | 106-35-4 | 50 | 230 | - |

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

## What dir.ca.gov says

> 106354 | | Ethyl butyl ketone; 3-heptanone | 50 | 230 | | 75 | 345

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

## Source

- https://www.cdc.gov/niosh/npg/npgd0266.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/).