In 2000, Life magazine compiled a list of the Top 100 Events of the past millennium. The introduction of chlorine as a water-sanitizing agent registered No. 46.

The advent of chlorine water sanitization has stemmed the tide of cholera and typhoid epidemics, among countless other maladies.

For example, in 1991, Peru experienced its first cholera outbreak since the turn of the century. The culprit? International health officials said the disease was the result of the Peruvian government discontinuing well-water chlorination. This occurred after the U.S. Environmental Protection Agency revealed studies that pointed to an increase in cancer risks due to trihalomethanes (THM), a chlorine byproduct. That could cause up to 700 additional cancer cases per year in the United States. Yet the Peruvian cholera epidemic claimed nearly 4,000 lives in one year alone.

Nevertheless, several studies over the past decade have linked chlorine to a variety of health and environmental concerns.

Experts say the chlorine debate is not black and white. “It is a double-edged sword. Anyone who takes a position that [chlorine] is bad and should be banned is failing to see it’s a more complex issue,” says Tom Lachocki, CEO of the National Swimming Pool Foundation in Colorado Springs, Colo.

“Not all chlorine has the same properties,” adds Lachocki, who has a Ph.D. in organic chemistry. “There is good and bad on every side, and you have to look at the issue with caution.”

So just how real is the threat? And, if one exists, what does it mean for the pool and recreational water industries?

Study time

As a pool sanitizer, the most recent indictment of chlorine came in the form of several studies linking it to a surge in childhood asthma rates. Three years ago, research published in a peer-reviewed journal called Occupational and Environmental Medicine

implicated trichloramine, a volatile byproduct of chlorination, as the probable cause.

The study, conducted between 1996 and 1999, looked at nearly 2,000 children between ages 7 and 14. The data revealed that regular attendance at indoor pools was associated with respiratory epithelium, a condition caused by the destruction of cells protecting the lungs.

A Belgian study presented research that reached the same conclusion. Dr. Simone Carbonnelle looked at 226 schoolchildren and monitored their time spent in and around swimming pools. Carbonnelle, who works at the industrial toxicology and occupational medicine unit at the Catholic University of Louvain in Brussels, noted that their level of lung permeability was equivalent to what one would find in a heavy smoker.

The pool/asthma connection also came to light in a study conducted at Birmingham Heartlands Hospital in England. It was headed by Dr. K. Thickett of the Occupational Lung Diseases Unit. The research pointed out that the problem isn’t actually the chlorine itself. Instead, it’s what chlorine turns into when it reacts with organics in the pool water. These chemicals include nitrogen trichloride, aldehydes, chloroform, trihalomethanes and chloramines.

Defenders of chlorine say that with adequate water and air management, the problems are easily circumvented. “Proper chlorination will control chloramine levels,” says Jeffrey Sloan, director of the disinfection program at the Chlorine Chemistry Council, a division of the American Chemistry Council, in Arlington, Va. “They can also be controlled through proper ventilation.

“It’s a matter of good practices,” he adds. “Swimmers also have a responsibility not to bring contaminants into the pool [by showering beforehand].”

Sloan notes that the asthma/chlorine studies “raise a lot more questions than they answer. They never measured air quality levels in those pools, or showed which contaminants they’re actually studying.”

Alison Osinski, Ph.D., spends a lot of time inspecting and evaluating indoor pools and natatoriums. The majority of those she visits have indoor air quality problems, which is something that many of the studies overlook.

“Chlorine in the air is not the same as chlorine in the water, and many of these studies don’t distinguish between them,” says Osinski, owner of Aquatic Consulting Services in San Diego. “The scare stories on these studies are usually all about air quality. Not all the architects and engineers [who build indoor pools] get it.”

But other studies claim that the effects of chlorine use — especially in drinking water applications — may be far more insidious than asthma. In 2000, a Norwegian study linked the chemical to an increase in birth defects, such as spina bifida. The research looked at 141,000 births over a three-year period and noted a 14 percent increase in the risk of defects in areas with chlorinated water.

“This is an important finding because we know there are chemicals released by the action of chlorine on organic particles at treatment works,” says Dr. Per Magnus, head of the Norwegian research, in an article inThe Electronic Telegraph, an online daily U.K. newspaper. “We have observed mutations in these chemicals which seem to tie up with mutations that are found in babies.”

Other research has linked chlorine to miscarriages, as well. But a 2005 national study conducted by scientists from the University of North Carolina — considered to be the most comprehensive study done on the subject — concluded that women with “higher exposure to trihalomethanes through drinking water had no great risk of pregnancy loss than other women.”

The Chlorine Chemistry Council points out that existing EPA regulations limit trihalomethanes in drinking water. It says it supports measures to reduce disinfection byproducts (DBPs). The council has stated that chlorine byproducts are some of the most studied and tightly regulated. It points to an EPA study that suggests switching from chlorination to alternative disinfectants may reduce regulated DBPs, but may increase exposure to potentially toxic and nonregulated compounds.

The council also notes that the World Health Organization put many of these studies under its own microscope in preparing guidelines for recreational water. “Just this year, the WHO came out with its new health-based guidelines, and it looked at all these issues,” Sloan says. “The bottom-line conclusion was that the risk from a well-managed pool would be small when weighed against the greater risk of microbial infection.”

But many critics remain convinced that chlorine is dangerous in any application. “Of the thousands of organochlorines in production, only a small fraction has been subject to basic toxicity testing, and complete health hazard information is available for none,” stated biologist Joe Thornton in a book calledPandora’s Poison: Chlorine, Health and a New Environmental Strategy (MIT Press, 2000).

“Developing the information base to predict the health impacts of each chemical would take centuries,” added Thornton, a research scientist at Columbia University and the former research coordinator for Greenpeace. “In the meantime, the public is exposed to a cocktail of untested substances.”

Thus, the debate over chlorine is not likely to be resolved any time soon.

According to a white paper presented by award-winning journalists Michelle M. Malkin and Michael Fumento, “As long as the environmentalists’ view that all synthetic chemicals are ‘guilty until proven innocent’ prevails, no amount of exculpatory evidence will ever be enough to clear an arbitrarily indicated chemical.”

Cooler heads

Some scientists and academics believe that zealots on both sides of the issue have clouded the debate with exaggerated language. They say cooler heads are needed to truly protect the public.

Medicinal chemist Richard Cavestri, Ph.D., says how one looks at the chlorine debate “depends on where your politics lie.” “It’s easy to wave the flag,” notes the president of Imagination Resources, a research and development contract laboratory in Dublin, Ohio. “But chlorine in the pool industry is regulated. It’s there to prevent biological and environmental contamination.

“Remember, you can make anything look toxic in lab studies if you want,” Cavestri adds.

He also points out that chlorine is essentially salt. Some form of it can be found just about everywhere — on our skin and in our food, for example. “We take in 5- to 7 grams of sodium chloride a day,” Cavestri says. “That’s in excess of what’s in a pool, but this is in the form of a chloramine. That’s 3 ppm, which is nothing.”

Some scientists say those with extreme views on the issue aren’t keeping things in perspective. It’s a matter of balancing the hazard vs. the risk.

“I think people have been selective in using information and facts about chlorine to substantiate their own point of view,” says toxicologist Gary Wright, Ph.D., president of the Wright Alliance, a product safety/advocacy consulting firm specializing in regulatory sciences in Winchester, Ky.

“By peeling the onion, you see the benefits and risks, and then the probability of the risks and what they mean to human health,” he adds.

Others say that managing the risk by controlling exposure is crucial.

Steven Ashkin, president of The Ashkin Group, LLC, a Bloomington, Ind.-based consulting firm with a mission to “green” the commercial cleaning industry, admits that chlorine has many valuable uses. He says it has provided consistent sanitization around the world since its advent more than a century ago. However, he believes American industry needs to start looking into alternatives for chlorine — not just in water sanitization, but for all of its applications.

Long-term exposure may be where the problems lie. “The other side of all this is that [chlorine] is a 50-year old technology,” Ashkin says. “Our goal is to protect the public, and we are now seeing new innovations that are effective at removing biological contaminants and reducing the unintended adverse impact associated with chlorine.”

Ashkin doesn’t advocate banning chlorine, but he contends that we need to continue to look into other ways to protect the public’s health. For example, he advocates the use of hydrogen peroxide instead of chlorine as a bleaching agent for the paper industry. He’d also like to see the pool industry step up its use of ozone, UV and ionization sanitization methods as a way to cut back on chlorine usage.

“There are many things they can do to reduce the overall environmental impact of their operations,” Ashkin says. “It’s in everything they touch, from paints to lights and all the chemicals they use.”

The future

What would happen if we didn’t use chlorine? The results would be devastating because cholera and other waterborne diseases would rage out of control, experts say.

For now, there are checks and balances to protect us from disease and the byproducts resulting from the products used to kill those deadly microbes. “If we didn’t have chlorine, we would have big problems and the economic impact would be huge,” Osinski says. “There are places in the world where people are still dying of cholera, dysentery and typhoid. But [in the industrial world], it’s the reason our life spans are longer — we have clean drinking water.

“Right now, you are surrounded by chlorine products: the computer you’re typing on, the paper you print on, the herbicides in your garden and the cosmetics you use every day,” she adds. “Many people don’t realize it, but the problem is not with chlorine itself. It’s when it is not used and handled properly, and gets sent into the environment in ways not intended.”


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