The agency will accept data from companies and researchers for one year before beginning to finalize the rule.
The proposal comes more than 40 years after the FDA began evaluating triclosan, triclocarban and similar ingredients. The government only agreed to publish its findings after a three-year legal battle with the Natural Resources Defense Council, an environmental group that accused the FDA of delaying action on potentially dangerous chemicals. Triclosan is found in an estimated 75 percent of anti-bacterial liquid soaps and body washes sold in the U.S., including some brands of Dial from Henkel AG & Co., one of the nation's largest soap makers.
More than 93 percent of bar soaps also contain triclocarban or triclosan, according to the FDA.
The FDA was asked to confirm those benefits in 1972, as part of a law designed to set guidelines for dozens of common anti-bacterial cleaners. But the guidelines got bogged down in years of regulatory delays and missed deadlines. The agency published a preliminary draft of its findings in 1978, but never finalized the results until Monday.
Most of the research surrounding triclosan's safety involves laboratory animals, including studies in rats that showed changes in testosterone, estrogen and thyroid hormones. Some scientists worry that such changes in humans could raise the risk of infertility, early puberty and even cancer.
FDA scientists stressed Monday that such studies are not necessarily applicable to humans, but the agency is reviewing their implications.
On a conference call with journalists, Kweder noted that the government's National Toxicology Program is already studying whether daily skin exposure to hormone-altering chemicals could lead to cancer.
Other experts are concerned that routine use of anti-bacterial chemicals such as triclosan contributes to a surge in drug-resistant germs, or superbugs, that render antibiotics ineffective.
In March 2010, the European Union banned the chemical from all products that come into contact with food, such as containers and silverware.
A spokesman for the American Cleaning Institute, a soap and cleaning product trade organization, said the group will submit new data to regulators, including studies showing that company products do not lead to antibiotic resistance.
"We are perplexed that the agency would suggest there is no evidence that anti-bacterial soaps are beneficial," said Brian Sansoni. "Our industry sent the FDA in-depth data in 2008 showing that anti-bacterial soaps are more effective in killing germs when compared with non-anti-bacterial soaps."The group represents manufacturers including Henkel, Unilever, Colgate-Palmolive Co. and Dow Chemical Co.