P.O. Box 40441, Providence, RI 02940

Tel. 401-351-9193, E-Mail:


(Sharing Information on Toxics in Everyday Life

& Providing Healthier Alternatives)



Children’s Health Environmental Coalition (CHEC)



Common Names: chloramine, sodium hypochlorite, bleach, hydrochloric acid, trihalomethanes, disinfection byproducts

Chlorine is a highly corrosive gas with a pungent odor that is derived from natural sources such as salt (sodium chloride) and produced in mass quantities for industrial use.  Chlorine is a building block for PVC plastics (vinyl) and for numerous chemicals, including pesticides, refrigerants, anti-knock compounds, and antifreeze.  Dissolved in liquid to form sodium hypochlorite, or bleach, it is widely used as a disinfectant, in bleaching, and to purify public water supplies.  Another form, hydrochloric acid, may be used in some toilet bowl cleaners.

Household bleach is a weak sodium hypochlorite solution.  Household bleach is the most common cleaner accidentally swallowed by children.  Children can also be exposed to dangerous gases when cleaners containing bleach are mixed with other cleaning agents, such as ammonia.

Concern about chlorine exposure also arises from its ability to form more toxic byproducts.  Chlorine reacts with organic matter in drinking water to produce trihalomethanes, which may cause cancer and possibly developmental effects.  A recent study links children's exposure to one byproduct, nitrogen trichloride, in chlorinated indoor pools to asthma.  Chlorine bleaching of paper and the manufacture and incineration of PVC plastic results in the formation of highly toxic dioxins and furans.


Significant Statistics:


In 2000, poison control centers in the United States reported that  chlorine  bleach was implicated in exposures to 18,863 children under the age of six.

            From: Litovitz. "2000 AAPCC Annual Report." American Journal of Emergency Medicine, Vol. 19, No.5 (September 2001), pg. 375.

The total inhalation exposure of  chlorine and chlorine byproducts due to showering, dishwashing and water boiling is comparable to that from dietary exposure.

            From: Lin, T.F., Hoang, S.W. "Inhalation exposure to THMs from drinking water," Water Supply, Vol. 17, No. 3 (1999), pp. 169-175.

Trihalomethanes, toxic byproducts of  chlorine disinfection of water supplies, may cause more than 10,000 cases of bladder and rectal cancer each year, according to an analysis of more than a dozen peer-reviewed, published, epidemiological studies.

            From: Morris, R.D., et al. "Chlorination, Chlorination By-Products, and Cancer: A Meta-Analysis," American Journal of Public Health, Vol. 87, No. 7 (1992), pp. 955-63.

The largest use of  chlorine is as a raw material in the production of PVC plastic (vinyl).

            From: Chemical Summary for Chlorine. U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics, August 1994.

In 1995, 98% of U.S. drinking water was purified by  chlorine.  Water treatment uses only about 5% of the chlorine produced nationally each year, however.

            From: Tibbetts, John. "What's in the Water: The Disinfectant Dilemma," Environmental Health Perspectives, Vol. 103, No. 1 (January 1995).


Health Effects


            Chlorine  bleach can cause severe skin and eye irritation or chemical burns to broken skin.

            Possible slight increase in the risk of bladder and rectal cancers in long-time users of chlorinated water supplies.

            Inhaled in high concentrations, can cause respiratory problems including coughing, choking, chest pain, emphysema, chronic bronchitis.  A recent study links children's exposure to nitrogen trichloride, a chlorination byproduct, at indoor swimming pools to an increased risk in developing asthma.

            Inhalation of  chlorine gas can corrode the teeth.

            In laboratory animals, repeated inhalation of  chlorine has damaged the liver, kidney, blood, heart, and immune and respiratory systems.


How Exposures Occur


            Cleaning Products Cleaners containing  bleach could be swallowed by children. Clear products may be mistaken for water.  Children can inhale toxic chlorine gases if products containing bleach are mixed with  ammonia or cleaners containing acids, such as some toilet bowl and oven cleaners.

            Chlorinated Swimming Pool Treatments  Children can inhale significant amounts of  chlorine and chlorination byproducts at levels potentially damaging to their lungs from chlorinator tablets in pools, particularly if they frequently swim in indoor pools, and if high levels of urine or other acidic compounds are present in water.  Exposure to chlorine from a typical swim is roughly the same as occupational chlorine exposures. Chloroform, a trihalomethane, is the volatile byproduct present at highest levels.  It is a carcinogen and developmental toxicant, among other things.  Exposure to chloroform from a typical swim is equivalent to an entire week's exposure from drinking and showering.  Exposure is best kept at a minimum.

            Drinking Water Disinfected with Chlorine  Children can ingest small amounts of  chlorine and its byproducts in drinking water that has been treated with chlorine to kill microbes.

            Steam from Showers and Appliances  Children can inhale  chlorine and its byproducts in steam from showers and baths.  These toxins can also be absorbed through the skin.  Steam from dishwashers using chlorinated water also contains chlorine and byproducts.




How to detect chlorine

            Cleaning products containing  chlorine are sometimes labeled as such, but chlorine can also be identified by its strong, distinct odor. 


How to minimize exposure to chlorine

            Avoid cleaning with chlorine-based products, especially if you or your children have asthma

or chronic lung or heart problems.  If you do use cleaning products that contain  chlorine, wear gloves

to avoid direct contact with skin, and provide plenty of ventilation by opening windows.  Keep children out of the room! 

To prevent the creation of toxic  chlorine or  chloramine gases, which can damage lungs and cause coughing and choking, never mix chlorine-containing cleansers with other cleaning products, particularly ones containing  ammonia or other acidic substances. 

            Carbon filters can remove the  chlorine and chlorine disinfection byproducts from water.  These filters are available for showerheads.  It is extremely important to change filters regularly.  Otherwise, the filters will start releasing contaminants back into the water. 

            To reduce chlorine and  trihalomethanes (THMs) in drinking water: - Store drinking water in pitchers.  About 20% of the THMs will evaporate from the water. -Drink hot beverages (rather than cold tap water).  The THMs and chlorine will evaporate. Cooking also helps reduce THMs intake, but the steam will expose the cook.  (Do not use hot water from the tap as hot water leaches  lead from pipes.) 




            Chlorine-free cleaning products, disinfectants, and laundry bleaches.  Some are made with hydrogen peroxide.  Chlorine-free cleaning products are are available at most natural foods stores and by mail order.  See also Antibacterials and Disinfectants: Safer Way to Keep Germs at Bay.  

            To prevent the entry of toxic chlorine byproducts into the environment, avoid buying and using PVC (vinyl) plastic products and chlorinated pesticides.  Choose recycled and unbleached, or chlorine-free paper products.  For more information, go to the Chlorine Free Products Association website.

            Install an ozonator in your swimming pool, hot tub or jacuzzi to reduce the amount of  chlorine needed.  Many pool supply retail stores have them. 


For More Information


Books, articles, fact sheets and reports


Dickey, Philip. Safer Cleaning Products. Washington Toxics Coalition, May 1998.|0|0


Other government agencies


U.S. Environmental Protection Agency Office of Ground Water and Drinking Water

Ariel Rios Building, 1200 Pennsylvania Avenue, NW, Washington, DC 20460-0003 organizations


Chlorine Free Products Association, 19 North Main Street, Algonquin, IL 60102  847-658-6104


Greenpeace USA702 H Street, NW, Washington, DC 20001  800-326-0959


Washington Toxics Coalition, 4649 Sunnyside Ave N, Suite 540, Seattle, WA 98103



Other websites


Pesticide Action Network Pesticide Database

Greenpeace USA Toxics Campaign

Environmental Defense Chemical Scorecard




            Chemical Summary for  chlorine. U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics, August 1994.

            Chemicals in the Environment:  chlorine. U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics, August 1994.

            Chlorine Chemical Backgrounder. National Safety Council.

            Chlorine, CASRN: 7782-50-5 (Human Health Effects). Toxnet Hazardous Substances Data Bank, National Library of Medicine, February 2002.

            Agent Monograph: Chlorinated Drinking-Water. World Health Organization, International Agency for Research on Cancer, November 17, 1997. (link has expired)

            Harte, John, et al. Toxics A to Z: A Guide to Everyday Pollution Hazards. Berkeley and Los Angeles: University of California Press, 1991.

            Tibbetts, John. "What's in the Water: The Disinfectant Dilemma." Environmental Health Perspectives, Vol. 103, No. 1 (January 1995).

            Chlorine. Health Effects Notebook for Hazardous Air Pollutants. U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards,

May 7, 2001.  (link has expired)

            Morris, R.D., et al. "Chlorination, Chlorination By-Products, and Cancer: A Meta-Analysis." American Journal of Public Health, Vol.87, No.7 (1992), pp.955-63.

            Drinking Water and Health, Volume 7: Disinfectants and Disinfectant By-Products. National Academy of Sciences, Commission on Life Sciences, 1987.

            Corsi, Richard, et al. "Household Appliances and Indoor Air Pollution," Environmental Science and Technology, July 1999.

            Rushall, Brent. "Chlorine Toxicity: A Matter That Should be of Concern to All Swimmers, Coaches, andParents," Swimming Science Journal .

            Graves, CG, Matanoski GM, Tardiff RG. "Weight of evidence for an association between adverse reproductive and developmental effects and exposure to disinfection by-products: a critical review," Regulatory Toxicology & Pharmacology, Vol. 34, no. 2 (2001), 103-24.

            Jo, W. "Chloroform in the water and air of Korean indoor swimming pools using both  sodium hypochlorite and ozone for water disinfection," J Exposure Analysis and Env Epidemiol., Vol. 4 (1994), 491-502.

            Drobnic F, Assumpcio F. "Assessment of  chlorine exposure in swimmers during training," Medicine and Science in Sports and Exercise, Vol. 28 (1996), 271-274

            Lin, T.F., Hoang, S.W. "Inhalation exposure to THMs from drinking water," Water Supply, Vol. 17, No. 3 (1999), 169-175.

            Batterman, S., Huang, A.T. ,Wang, S., Zhang, L. "Reduction of Ingestion Exposure to  trihalomethanes Due to Volatilization," Environmental Science & Technology, Vol. 34, no. 20 (2000), 4418-4424.


For more information, or to share your own concerns, problems, comments, questions, contact:

Toxics Information Project (TIP), P.O. Box 40441, Providence, RI 02940,

Tel. 401-351-9193,  E-Mail:  Website:

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