11/19/2025 / By Evangelyn Rodriguez

For decades, chlorinated tap water has been considered a hallmark of public health safety—effectively eliminating harmful pathogens and preventing waterborne diseases. Yet mounting scientific evidence suggests that this widespread disinfection method may come at a steep cost: an increased risk of cancer.
Research from institutions such as the Medical College of Wisconsin has uncovered alarming connections between long-term consumption of chlorinated water and elevated rates of colorectal and bladder cancers. With over 98% of U.S. water supplies treated with chlorine, millions of Americans may unknowingly be exposing themselves to carcinogenic byproducts—raising urgent questions about water safety regulations and public health priorities.
Chlorine, while effective at killing bacteria, reacts with organic matter in water to form toxic compounds known as trihalomethanes (THMs). These byproducts—including chloroform, a Group B carcinogen—have been linked to serious health risks, including cancer, heart disease and reproductive harm.
A landmark meta-review published in the American Journal of Public Health pooled data from ten studies and found that individuals consuming chlorinated water faced a 21% higher risk of bladder cancer and a 38% increased risk of rectal cancer compared to those drinking non-chlorinated water. The researchers estimated that chlorinated water accounts for 6,500 cases of rectal cancer and 4,200 cases of bladder cancer annually in the U.S.
Further supporting these findings, a Swedish cohort study published in the Journal of the National Cancer Institute tracked nearly 59,000 individuals over 16.8 years. Researchers found that men exposed to higher THM levels (?15 micrograms, mcg/liter, L) faced a significantly elevated risk of colorectal cancer, particularly in the proximal colon.
Other THMs to watch out for, according to BrightU.AI‘s Enoch engine, include bromodichloromethane, dibromochloromethane and bromoform (tribromomethane), all of which are linked to increased risks of bladder, rectal, kidney, stomach, brain and pancreatic cancers, as well as liver damage, reproductive toxicity and neurological effects.
Despite the mounting evidence, concerns about chlorinated water have often been downplayed or ignored. A co-author of the American Journal of Public Health study revealed that their research was suppressed for a year before publication, with major journals reluctant to publish findings that could alarm the public without presenting an immediate alternative.
When the New York Times finally covered the study, it framed the increased cancer risk as “very slight”—despite the study’s conclusion that chlorinated water was responsible for thousands of cancer cases annually. Meanwhile, the U.S. Environmental Protection Agency (EPA), while acknowledging the potential dangers of THMs, has yet to enforce stricter regulations or mandate safer disinfection alternatives.
The dangers of chlorinated water extend beyond cancer. Studies have linked THM exposure to:
Canadian researchers have also found that just one hour in a chlorinated pool significantly increases chloroform levels in the bloodstream. Similarly, hot showers release chloroform vapor, which can be absorbed through the skin and lungs.
Given the pervasive presence of chlorine in water supplies, experts recommend several proactive measures to reduce exposure:
While chlorine has played a crucial role in preventing waterborne diseases, its long-term health consequences can no longer be ignored. With thousands of cancer cases linked to chlorinated water each year—and broader risks to cardiovascular and reproductive health—regulators must prioritize safer disinfection methods, such as ozonation or UV treatment, to reduce reliance on chlorine.
In the meantime, public awareness and individual precautions remain essential. As scientific scrutiny grows, the question remains: Will policymakers act to protect public health or will corporate and bureaucratic inertia continue to leave millions at risk?
For now, the responsibility falls on consumers to safeguard their own health—one filtered glass of water at a time.
Learn about the dangers of chlorinated pools by watching this video.
This video is from the Daily Videos channel on Brighteon.com.
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Bladder cancer, cancer criminals, chlorinated pools, chlorinated water, chlorination, chlorine, Colorectal Cancer, Dangerous, health science, poison, real investigations, research, Suppressed, tap water, toxic chemicals, toxins, Trihalomethanes, water supply
This article may contain statements that reflect the opinion of the author