NIOSH logo and tagline

Hydrogen Chloride


CAS No. 7647-01-0

Hydrogen chloride (HCl) is a colorless to slightly yellow gas with a pungent odor. Hydrogen chloride can irritate the skin, nose, eyes, throat, and larynx. Exposure to liquid hydrogen chloride may cause frostbite. Workers may be harmed from exposure to hydrogen chloride. The level of harm depends upon the dose, duration, and work being done.

Hydrogen chloride may be used in the workplace for fumigation, electroplating, mining, chemical synthesis, and the production of synthetic fibers, plastics, dyes, and pesticides. Some examples of workers at risk of being exposed to hydrogen chloride include the following:

  • Workers who  fumigate ships and buildings
  • Agricultural workers who fumigate outdoor pests in areas such as fruit orchards
  • Factory workers in industries that manufacture acrylic fibers, synthetic rubber, and plastics
  • Steel and iron workers who work in plants that harden iron and steel

NIOSH recommends that employers use the Hierarchy of Controls to prevent injuries. If you work in an industry that uses hydrogen chloride, please read chemical labels and the accompanying Safety Data Sheets for hazard information. Visit NIOSH’s page on Managing Chemical Safety in the Workplace to learn more about controlling chemical workplace exposures.

The following resources provide information about occupational exposure to hydrogen chloride. Useful search terms for hydrogen chloride include “anhydrous hydrogen chloride” “aqueous hydrogen chloride,” and “hydrochloric acid.”

NIOSH Chemical Resources

Related NIOSH Resources

Selected Publications

Related Resources

International Resources