Antibacterial soap may expose hospital workers to significant and potentially unsafe levels of triclosan, a widely-used chemical currently under review by the U.S. Food and Drug Administration, according to a recent study.

Triclosan, a synthetic antibacterial agent, is found in thousands of consumer products, including soaps, cosmetics, acne creams and some brands of toothpaste. The FDA is reviewing its safety based on a growing body of research indicating that it can interfere with the action of hormones, potentially causing developmental problems in fetuses and newborns, among other health concerns.

"Antimicrobial soaps can carry unknown risks, and triclosan is of particular concern," said co-investigator Paul Blanc, a professor of medicine at the University of California at San Francisco. "Our study shows that people absorb this chemical at work and at home, depending on the products that they use."

For the study, researchers analyzed urine samples from two groups of 38 doctors and nurses - three fourths of them women - at two hospitals, identified as Hospital 1 and Hospital 2. Hospital 1 used an antibacterial soap containing 0.3 percent triclosan, while Hospital 2 used plain soap and water.

Workers at Hospital 1 had significantly higher levels of triclosan in their urine than workers at Hospital 2.

The scientists also asked the study participants if they used a popular commercial toothpaste containing triclosan. While those who did had higher triclosan levels than those who did not, the researchers found that washing with antibacterial soap accounted for even higher triclosan levels than did brushing with the toothpaste.

Blanc recommended that "if non-triclosan-containing soaps are available, use the alternative. This is based on the precautionary principle - that is, if you don't know for certain that something is unsafe, it's better to err on the side of caution."

The same principle "could be applied more generally in this case," Blanc said. "It should not be up to the individual to inspect every product for triclosan. Instead, it's the duty of the FDA to carry out a review of this chemical and, if indicated, get it off the market."

Blanc said plain soap and water is a good alternative to antibacterial soap.

The findings were recently published in the Journal of Occupational and Environmental Medicine.