Hydrogen cyanide
For Hydrogen cyanide, cas no. is 74-90-8; pel (ppm) is 10; pel (mg/m³) is 11, verified against its source on 2026-08-05.
- Substance
- Hydrogen cyanide
- CAS No.
- 74-90-8
- PEL (ppm)
- 10
- PEL (mg/m³)
- 11
What the source says
Hydrogen cyanide | 74-90-8 | 10 | 11 | X |
— osha.gov, retrieved 2026-08-05
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 10, as of 2026-08-05.
Hydrogen cyanide | 74-90-8 | 10 | 11 | X |
https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
dir.ca.gov says pel (ppm) is 4.7, as of 2026-08-05.
74908 | S | Hydrogen cyanide | 4.7 | 5 | C
https://www.dir.ca.gov/title8/5155.html
PEL (mg/m³)
osha.gov says pel (mg/m³) is 11, as of 2026-08-05.
Hydrogen cyanide | 74-90-8 | 10 | 11 | X |
https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
dir.ca.gov says pel (mg/m³) is 5, as of 2026-08-05.
74908 | S | Hydrogen cyanide | 4.7 | 5 | C
Sources
- osha.govhttps://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
- dir.ca.govhttps://www.dir.ca.gov/title8/5155.html