It's a comforting time to be a germ freak. In addition to anti-bacterial hand soaps and shampoos, the microbe-averse can buy bacteria-fighting clothes, toys, towels, sheets, sponges, mops and even pens.

Never mind that trillions of bacteria happily live on our skins and noses and in our mouths and intestines. Or that some exposure to germs helps develop a healthy immune system.

In 2004, Americans spent more than $540 million on anti-bacterial soaps, hand cleaners and detergents that contain chemicals such as triclosan to kill germs, though a U.S. Food and Drug Administration panel found that they are no better than soap and water. People in healthcare settings may see benefits, but not in the general population.

The issue isn't just that, for most of us, products impregnated with germ-fighting chemicals are a waste of money. It's not even that they could promote the growth of antibiotic-resistant bacteria, something the Soap and Detergent Association maintains happens in the lab but not in the real world.

The association says people confuse anti-bacterial with antibiotic. If there were a link, the organization says, it likely would have been seen in settings such as hospitals, and it also says the rampant overuse of antibiotics by doctors to treat infection likely plays a far greater role in the rise of super-resistant bugs.

More disturbing is that the germ-fighting chemicals found in anti-bacterials, namely triclosan and triclocarban, are turning up in fish, breast milk and wastewater. Then they are released into the environment through municipal sludge, which is recycled and spread on agricultural fields.

Although this has been going on for the past 50 years, scientists only recently looked into what happens once the chemicals are flushed down the drain. This all concerns researchers such as Rolf Halden, assistant professor at the Center for Water and Health at Johns Hopkins Bloomberg School of Public Health.

The United States Geological Survey has shown that triclosan, which mimics the thyroid hormone and is commonly added to soaps, toothpaste, deodorant, dog shampoo, cutting boards, clothing, toys and other anti-bacterial products, is present in 60 percent of U.S. waterways investigated.

Halden's studies showed a similar dispersal of triclocarban, triclosan's chemical brother, which is found mostly in deodorant bar soaps.

Both chemicals are known by several other names, and annually more than 1 million pounds of each are used in the U.S. alone.

Though the amounts turning up are minute, a recent study has shown it is enough to disrupt thyroid function in frogs. Equivalent data on humans isn't yet available.

As ingredients in products, the chemicals aren't necessarily harmful to humans, scientists say. But evidence is mounting that "these chemicals are remarkably persistent and possibly bioaccumulating, not only through products (applied to the skin) but environmentally through drinking water and potentially contaminated crops," said Halden, a member of the FDA panel that looked at the benefits and hazards of antiseptic hand soaps.

Now he and other scientists are asking: Do the potential benefits of anti-microbial products outweigh their possible environmental human health risks?

"Plain old soap and water also removes and kills micro-organisms and has done so for thousands of years," Halden said.

Also, anti-bacterial soaps don't prevent colds or flu, which are caused by viruses, not bacteria. And most experts say that unless you're in a hospital environment, using products with triclosan — a biocide that can destroy biological structures at random — is like using a jackhammer to kill an ant.

The American Medical Association has opposed routine use of anti-bacterial soaps since 2002. This year, the Canadian Pediatric Society asked parents to stop buying anti-bacterial products and instead use soap and water to wash toys, hands and household items. Allison Janse, co-author of the indispensable manual "The Germ Freak's Guide to Outwitting Colds and Flu" (Health Communications, $11.95 paper), points out that when you buy an anti-bacterial cutting board and put raw chicken on it, you've just contaminated it. Buying these products, she said, "may give some people a false sense of security."

There is a place for anti-bacterial products: a hospital. Think twice about using them in your home for everyday use, especially when soap and water are just as effective. And much cheaper.