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Chlorine

Overview

CAS No. 7782-50-5

Chlorine (Cl₂) is a greenish-yellow gas with a pungent, irritating odor. Exposure to low levels of chlorine can result in nose, throat, and eye irritation. At higher levels, breathing chlorine gas may result in changes in breathing rate and coughing, and damage to the lungs. Additional symptoms of exposure to chlorine can be severe. Workers may be harmed from exposure to chlorine. The level of exposure depends upon the dose, duration, and work being done.

Chlorine is used in many industries. It’s used in the pulp and paper industries, pool chemical products, cleaning products, mining products, bleach and plastics manufacturing.  Some examples of workers at risk of being exposed to chlorine include the following:

  • Workers in water treatment and sewage facilities
  • Agricultural workers who clean livestock facilities, such as dairy farms
  • Workers who clean pools
  • Janitorial workers who use cleaning products
  • Factory workers in bleach and plastic manufacturing

NIOSH recommends that employers use Hierarchy of Controls to prevent injuries.  If you work in an industry that uses chlorine, please read chemical labels and the accompanying Safety Data Sheet 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 chlorine. A useful search terms for chlorine include “molecular chlorine.”

NIOSH Chemical Resources

Logo of NIOSH Pocket Guide

NIOSH Pocket Guide

The NIOSH Pocket Guide to Chemical Hazards (NPG) helps workers, employers, and occupational health professionals recognize and control workplace chemical hazards.

Logo of Manual of Analytical Methods.

Manual of Analytical Methods

The NIOSH Manual of Analytical Methods (NMAM) is a collection of methods for sampling and analysis of contaminants in workplace air, and in the blood and urine of workers who are occupationally exposed.

Logo of Health Hazard Evaluations consisting of three letters: HHE

Health Hazard Evaluations

The Health Hazard Evaluation Program (HHE) conducts onsite investigations of possible worker exposure to chemicals. Search the HHE database for more information on chlorine.

Selected Publications

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International Resources

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