Product Allergen Watch: Triclosan

Lauren Campbell; Matthew J. Zirwas


Dermatitis. 2006;17(4):204-207. 

In This Article

Potential Carcinogenicity

In addition to the concerns of bacterial resistance, there are also environmental concerns. Reports have suggested that triclosan can combine with chlorine in tap water to form chloroform gas, a gas the US Environmental Protection Agency classifies as a potential human carcinogen. As a result, triclosan has been the target of a cancer alert in the United Kingdom. In reality, one study showed that the amount of chloroform gas generated was less than the amount present in regular chlorinated water.[50]

In the laboratory, it has been shown that triclosan can react with the free chlorine in water to produce lesser amounts of other potentially harmful compounds, including 2,4-dichlorophenol. These intermediates can convert to dioxins upon exposure to ultraviolet radiation. Although very small amounts of dioxins are produced, there is concern over this effect because dioxins are very toxic and are potent disruptors of the endocrine system. Dioxins are also chemically stable, are eliminated from the body slowly, can accumulate to dangerous levels, and remain in the environment for long periods.[50] It is unclear if this conversion of triclosan to dichlorophenol to dioxin can occur outside the laboratory setting.


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