Chlorine is used almost universally in the treatment of public drinking water because of its toxic effect on harmful bacteria and other waterborne, disease causing organisms. But there is a growing body of scientific evidence that shows that chlorine in drinking water may actually pose greater long term dangers than those for which it was used to eliminate. These effects of chlorine may result from either ingestion or absorption through skin. Scientific studies have linked chlorine and chlorination by-products to cancer of the bladder, liver, stomach, rectum, and colon, as well heart disease and arteriosclerosis (hardening of the arteries), anemia, high blood pressure, and allergic reactions. There is also evidence that shows that chlorine can destroy protein in our body and cause adverse effects on skin and hair. The presence of chlorine in water may also contribute to the formation of chloramines in the water, which can cause taste and odor problems. Since chlorine is required by public health regulations to be present in all public drinking water supplies, it is up to the individual to remove it at the point-of-use. The best available method of chlorine removal, for the individual consumer, is to filter the water at the point of entry to the home, ensuring that no matter which tap or shower is used it will be chlorine free.


Although useful for killing many pests, chlorine is not especially effective against cysts and larger parasites a leading source of dysentery, worldwide and provides essentially no protection against Cryptosporidium. (More than 400,000 people were sickened by Cryptosporidium in Milwaukee in 1993; thousands were hospitalized, and more than 100 deaths were attributed to this parasite. More died in Las Vegas the next year, and there have been many other incidents… mostly on “safe” water supplies meeting all health safety standards.) Cryptosporidium, Giardia, and amoebic dysentery cysts are found essentially everywhere. Additionally, foul tastes and odors, sometimes coming from fiberglass storage tanks holding chlorinated water, can render water almost undrinkable, especially in the concentrations necessary for assured protection against bacteria growth.


Importantly, in addition to microbiological and aesthetic considerations, it is now well established that chlorine contributes to many known and suspected cancer-inducing agents such as chloroform, carbon tetrachloride and many other halogenated hydrocarbons. (Chlorine also has been implicated in heart disease.) Halogenated hydrocarbons are hydrocarbon pollutants that link chemically with chlorine, iodine, bromine or fluorine. This reaction needs only trace amounts of contaminant compounds, and since our nation’s waterways and water sources are practically all contaminated to at least a minor extent, the E.P.A. has estimated that probably all water supplies contain at least some cancer causing agents.


“In June 1988 the US National Cancer Institute released the results of an intensive 10,000 – person study, which showed that people who drink chlorinated water for long periods of time have twice the incidence of bladder cancer as those who don’t drink chlorinated water.

SCIENCE NEWS- 11 July 1992

“A new statistical analysis indicates that people who drink chlorinated water run a 21 percent greater risk of bladder cancer and a 38 percent greater risk of rectal cancer than people who drink water with little or no chlorine.” “I am quite convinced, based on this study, that there is an association between cancer and chlorinated water.”

NEW SCIENTIST 18 September 1986

“Taking long hot showers is a health risk, according to research presented last week in Anaheim, California, at a meeting of the American Chemical Society. Showers, and to a lesser extent baths, lead to greater exposure to toxic chemicals contained in water supplies than does drinking the water. The chemicals evaporate out of the water and are inhaled. They can also spread through the house and be inhaled by others. House holders can receive 6 to 100 times more of the chemical by breathing the air around showers and bath than they would by drinking the water.”


“On one hand, chlorination has freed civilization from the constant dangers of waterborne epidemics. On the other hand in the mid –70s scientists discovered that chlorination could create carcinogens in water. 80% of the population drinks chlorinated water. There was a higher incidence of cancer of the esophagus, rectum, breast and larynx and of Hodgkin’s Disease among those drinking chlorinated surface waters. Volatile organics can evaporate from water in a shower or bath. Conservative calculations indicate that inhalation exposures can be as significant as exposure from drinking the water, that is, one can be exposed to just as much by inhalation during a shower as by drinking 2 liters of water a day. People who shower frequently could be exposed through ingestion, inhalation and/or dermal absorption.”


“Showering is suspected as the primary cause of elevated levels of chloroform in nearly every home because of the chlorine in the water.”


“A Professor of Water Chemistry at the University of Pittsburgh claims that exposure to vaporized chemicals in the water supplies through showering, bathing, and inhalation is 100 times greater than through drinking water.”

“As chlorine is added to kill pathogenic microorganisms, the highly reactive chlorine combines with fatty acids and carbon fragments to form a variety of toxic compounds, which comprise about 30% of the chlorination by – products.”

“Epidemiological studies suggest a link between ingestion of toxic chemicals in the water and elevated cancer mortality risks.”


“Cancer risk among people drinking chlorinated water is 93% higher than among those whose water does not contain chlorine.”


“Drinking tap water that is chlorinated is hazardous, if not deadly to your health.”


“Known carcinogens are found in drinking water as a direct consequence of the practice of chlorination. A long established public health practice for the disinfection of drinking water.”

The simple solution is to install a water filter where it enters your house eliminating Chlorine at every tap and every shower head