Methyl acetylene — CAS 74-99-7 — workplace exposure limit
What is the niosh rel (ppm) for Methyl acetylene — CAS 74-99-7 — workplace exposure limit?
For Methyl acetylene, niosh rel (ppm) is TWA 1000; niosh rel (mg/m³) is 1650; cas no. is 74-99-7, verified against its source on 2026-09-08.
NIOSH REL TWA 1000 ppm (1650 mg/m3)
— cdc.gov, retrieved 2026-09-08
- Substance
- Methyl acetylene verified
- CAS No.
- 74-99-7 verified
- NIOSH REL (ppm)
- TWA 1000 verified
- NIOSH REL (mg/m³)
- 1650 verified
- PEL (ppm)
- 1000 per osha.gov
- PEL (mg/m³)
- 1650 per osha.gov
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 - Methyl acetylene
CAS No.
CAS No. 74-99-7
— all from cdc.gov, retrieved 2026-09-08
What osha.gov says
Methyl acetylene (Propyne) | 74-99-7 | 1000 | 1650 | - |
— osha.gov, retrieved 2026-08-05
What dir.ca.gov says
74997 | | Methyl acetylene; propyne | 1,000 | 1,650
— dir.ca.gov, retrieved 2026-08-05
What dir.ca.gov says
74997 | | Propyne; see Methylacetylene
— dir.ca.gov, retrieved 2026-08-05
Sources
- cdc.govhttps://www.cdc.gov/niosh/npg/npgd0392.html
- osha.govhttps://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
- dir.ca.govhttps://www.dir.ca.gov/title8/5155.html