Mesityl oxide — CAS 141-79-7 — workplace exposure limit
What is the pel (ppm) for Mesityl oxide — CAS 141-79-7 — workplace exposure limit?
For Mesityl oxide, pel (ppm) is disputed: 25 per osha.gov, 15 per dir.ca.gov; pel (mg/m³) is disputed: 100 per osha.gov, 60 per dir.ca.gov; cas no. is 141-79-7, verified against its source on 2026-08-05.
Mesityl oxide | 141-79-7 | 25 | 100 | - |
— osha.gov, retrieved 2026-08-05
- Substance
- Mesityl oxide verified
- CAS No.
- 141-79-7 verified
- PEL (ppm)
- 25 sources disagree
- PEL (mg/m³)
- 100 sources disagree
- NIOSH REL (ppm)
- TWA 10 per cdc.gov
- NIOSH REL (mg/m³)
- 40 per cdc.gov
- STEL (ppm)
- 25 per dir.ca.gov
- STEL (mg/m³)
- 100 per dir.ca.gov
What cdc.gov says
NIOSH REL TWA 10 ppm (40 mg/m3)
— cdc.gov, retrieved 2026-09-08
Substance
CDC - NIOSH Pocket Guide to Chemical Hazards - Mesityl oxide
CAS No.
CAS No. 141-79-7
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 — deciding between them is yours, not ours.
PEL (ppm)
osha.gov says pel (ppm) is 25, as of 2026-08-05.
Mesityl oxide | 141-79-7 | 25 | 100 | - |
https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
dir.ca.gov says pel (ppm) is 15, as of 2026-08-05.
141797 | | Mesityl oxide; 4-methyl-3-pentene-2-one | 15 | 60 | | 25 | 100
https://www.dir.ca.gov/title8/5155.html
PEL (mg/m³)
osha.gov says pel (mg/m³) is 100, as of 2026-08-05.
Mesityl oxide | 141-79-7 | 25 | 100 | - |
https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
dir.ca.gov says pel (mg/m³) is 60, as of 2026-08-05.
141797 | | Mesityl oxide; 4-methyl-3-pentene-2-one | 15 | 60 | | 25 | 100
Sources
- osha.govhttps://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
- cdc.govhttps://www.cdc.gov/niosh/npg/npgd0385.html
- dir.ca.govhttps://www.dir.ca.gov/title8/5155.html