Chlorine Facts for Pool & Spa Owners

Recently, the national media have carried stores about chlorine, reporting that "some scientists" and "an international commission" have suggested that chlorine and chlorine compounds may cause breast cancer.  Some suggest a chlorine "ban" is coming soon.

What did the reports say?

The Greenpeace Report, "Chlorine, Human Health and the Environment," widely cited as a source in news stories about chlorine and breast cancer, states that "organochlorines are by no means the only risk factor for breast cancer, and their role in incidence of the disease has not yet been proven..."  The essence of the Greenpeace report is basically a series of charts which show that breast cancer is more common in industrialized nations than in undeveloped areas, and that industrialized nations also use more chlorine and chlorinated compounds.

What about the proposed ban?

The Clinton Administration in early 1994 proposed that EPA develop a "strategy for substituting, reducing or prohibiting the use of chlorine and chlorinated compounds," in its proposed new Clean Water Act.  This proposal, however, was not included in the legistlation actually introduced in 1994, nor has the idea been revived in the Congress since that time.

Why we use chlorine

Ironically, eliminating chlorine would make our water less "clean," allowing disease to be spread through water-bourne pathogens, which chlorine now effectively controls in 98% of the nation's water supply.

What would a ban do?

A chlorine ban would be detrimental to the health and economic situation of all Americans.

--substitution for all current uses of chlorine would cost U.S. consumers over $90 billion per year.  (Charles River Associates, April 1993 report: "Assessment of the Economic Benefits of Chlor-Alkali Chemicals to the United States and Canadian Economies.")

--there are no adequate substitutions for some uses of chlorine, including water treatment.  (Even the anti-chlorine Greenpeace Report acknowledge this fact)  More than 98% of the drinking water supply in the U.S. is treated with chlorine.  Without chlorine treatment, the water supply would be the source of major public health epidemics, including diseases such as cholera and dysentery.

-- 85% of all pharmaceuticals, including vitamins and medicines that treat heart disease, hypertension, ulcers, leukemia, arthritis and pneumonia, require the use of chlorine chemistry for their production.

Does science support a ban?

All chlorinated compounds are not the same, and lumping the thousands of chemicals and products produced from chlorine is bad science.  Those compounds scientifically proven to be dangerous have already been banned (such as PCB and DT).  Banning all chlorine compounds because some are dangerous makes no sense at all.  Plastics such as PVC are chlorine compounds.  Ordinary table salt is a chlorine compound, which presumably would be banned under the administration proposal.

-- The U.S. Department of Health and Human Services National Toxicology Program, made up of representatives from the National Cancer Institute, National Institutes of Health, Food and Drug Administration, and the Center for Disease Control published a study on chlorinated and chloraminated water in 1992.  That two-year, long term study of eight groups of mice and rats, dosed with up to 275ppm of chlorine, or 200ppm of chloramine, found no evidence of carcinogenic activity in six of the group, and equivocal evidence in two groups.  (Equivocal defined by the study as "a marginal increase of newplasms that may be chemically related")  It should be noted that the levels of approximately 30 to 100 times higher than the levels of chlorine found in swimming pools, which is typically not ingested by pool users.

-- Dr. Susan Sieber, Deputy Director of the Division of Cancer Etiology, National Cancer Institute, says the idea that all chlorine-based chemicals should be banned, "is nonsense, based on data currently available.".

What's the bottom line?

No credible evidence exists that chlorine or pool chlorine compounds cause cancer  A chlorine ban would cost billions and would cause serious public health problems.  The proposal to spend $6 million to devise a strategy to ban or reduce chlorine use, without any scientific finding that the benefits of chlorine are outweighed by the risks, is bad science and bad public policy.

Are there alternatives to chlorine?

While chlorine continues to be the most popular sanitizer/disinfectant, there are a number of alternatives to using chlorine or a chlorine compound to sanitize your swimming pool, if you desire.  Keep in mind, however, that even non-chlorine systems require a chemical oxidizer of some sort, to eliminate organic materials in the water. Beware of claims for products which use fear of chlorine to sell their product; claims that chlorine is dangerous are false, and should make you skeptical of other claims as well.