Reference Source

Hydrogen chloride — CAS 7647-01-0 — workplace exposure limit

What is the pel (ppm) for Hydrogen chloride — CAS 7647-01-0 — workplace exposure limit?

For Hydrogen chloride, pel (ppm) is disputed: (C)5 per osha.gov, 0.3 per dir.ca.gov; pel (mg/m³) is disputed: (C)7 per osha.gov, 0.45 per dir.ca.gov; cas no. is 7647-01-0, verified against its source on 2026-08-05.

Hydrogen chloride | 7647-01-0 | (C)5 | (C)7 | - |

— osha.gov, retrieved 2026-08-05

(C)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.
Sourceosha.gov
Verified
Review by
DatasetUS workplace chemical exposure limits: federal OSHA, Cal/OSHA and NIOSH, side by side
Substance
Hydrogen chloride verified
CAS No.
7647-01-0 verified
PEL (ppm)
(C)5 sources disagree
PEL (mg/m³)
(C)7 sources disagree
Ceiling
2 ppm per dir.ca.gov
Ceiling notation
a ceiling value in addition to the TWA values per dir.ca.gov
NIOSH REL (ppm)
C 5 per cdc.gov
NIOSH REL (mg/m³)
7 per cdc.gov

What cdc.gov says

NIOSH REL C 5 ppm (7 mg/m3)

— cdc.gov, retrieved 2026-09-08

Substance

CDC - NIOSH Pocket Guide to Chemical Hazards - Hydrogen chloride

CAS No.

CAS No. 7647-01-0

What dir.ca.gov says

7647010 | | Hydrochloric acid; see Hydrogen chloride

— dir.ca.gov, retrieved 2026-08-05

What dir.ca.gov says

7647010 | | Muriatic acid; see Hydrogen chloride

— dir.ca.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 (C)5, as of 2026-08-05.

Hydrogen chloride | 7647-01-0 | (C)5 | (C)7 | - |

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

dir.ca.gov says pel (ppm) is 0.3, as of 2026-09-28.

7647010 | | Hydrogen chloride | 0.3 | 0.45 | 2 ppm

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

PEL (mg/m³)

osha.gov says pel (mg/m³) is (C)7, as of 2026-08-05.

Hydrogen chloride | 7647-01-0 | (C)5 | (C)7 | - |

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

dir.ca.gov says pel (mg/m³) is 0.45, as of 2026-09-28.

7647010 | | Hydrogen chloride | 0.3 | 0.45 | 2 ppm

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

Sources

Last verified against source: . Due for re-check by . This page as Markdown · OKF bundle · full dataset as JSON.

What is the OSHA exposure limit for this substance?Find the exposure limit for a substance in workplace air — federal OSHA, California and NIOSH, side by side.

Also see: Chemical reporting thresholds

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