Sulfur dioxide — workplace exposure limit
What is the pel (ppm) for Sulfur dioxide — workplace exposure limit?
For Sulfur dioxide, pel (ppm) is 5; pel (mg/m³) is 13; cas no. is 7446-09-5, verified against its source on 2026-08-05.
Sulfur dioxide | 7446-09-5 | 5 | 13 | - |
— osha.gov, retrieved 2026-08-05
5
The most of this substance workplace air may legally contain, averaged over an 8-hour shift — OSHA's permissible exposure limit (PEL), in parts per million, from the agency's own table row quoted below. Where federal OSHA and Cal/OSHA disagree, both limits are stated, each with its own agency's table row as evidence. NIOSH's number, where there is one, is shown separately: it is a recommended limit, not a legal one, and it is often the strictest of the three.
- Substance
- Sulfur dioxide verified
- CAS No.
- 7446-09-5 verified
- PEL (ppm)
- 5 verified
- PEL (mg/m³)
- 13 verified
- STEL (ppm)
- 5 per dir.ca.gov
- STEL (mg/m³)
- 10 per dir.ca.gov
- NIOSH REL (ppm)
- TWA 2 per cdc.gov
- NIOSH REL (mg/m³)
- 5 per cdc.gov
What cdc.gov says
NIOSH REL TWA 2 ppm (5 mg/m3) ST 5 ppm (13 mg/m3)
— cdc.gov, retrieved 2026-09-08
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 5, as of 2026-08-05.
Sulfur dioxide | 7446-09-5 | 5 | 13 | - |
https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
dir.ca.gov says pel (ppm) is 2, as of 2026-08-05.
7446095 | | Sulfur dioxide | 2 | 5 | | 5 | 10
https://www.dir.ca.gov/title8/5155.html
PEL (mg/m³)
osha.gov says pel (mg/m³) is 13, as of 2026-08-05.
Sulfur dioxide | 7446-09-5 | 5 | 13 | - |
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.
7446095 | | Sulfur dioxide | 2 | 5 | | 5 | 10
Sources
- osha.govhttps://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1
- dir.ca.govhttps://www.dir.ca.gov/title8/5155.html
- cdc.govhttps://www.cdc.gov/niosh/npg/npgd0575.html