# 5-Methyl-3-heptanone — workplace exposure limit

For 5-Methyl-3-heptanone, niosh rel (ppm) is TWA 25; niosh rel (mg/m³) is 130; cas no. is 541-85-5, verified against its source on 2026-09-08.

- **Substance:** 5-Methyl-3-heptanone _(verified: appears in its own passage below)_
- **CAS No.:** 541-85-5 _(verified: appears in its own passage below)_
- **NIOSH REL (ppm):** TWA 25 _(verified: appears in the quote below)_
- **NIOSH REL (mg/m³):** 130 _(verified: appears in the quote below)_
- **PEL (ppm):** 25 _(per osha.gov, not stated by the source above)_
- **PEL (mg/m³):** 130 _(per osha.gov, not stated by the source above)_

## What the source says

> NIOSH REL TWA 25 ppm (130 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 - 5-Methyl-3-heptanone

### CAS No.

> CAS No. 541-85-5

## What osha.gov says

> Ethyl amyl ketone (5-Methyl-3-heptanone) | 541-85-5 | 25 | 130 | - |

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

## What dir.ca.gov says

> 541855 | | Ethyl sec-amyl ketone; 5-methyl-3-heptanone | 25 | 130

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

## Source

- https://www.cdc.gov/niosh/npg/npgd0418.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/).