Every year, U.S. consumers spend an estimated $1 billion on household and personal care products to shield themselves from a host of unseen germs. Yet many items marketed for their so-called “anti-bacterial” properties contain an ingredient perhaps more insidious than the microorganisms they’re designed to combat: triclosan.

Invented by the chemical company Ciba in the 1960s to kill germs in medical settings, triclosan now appears in an array of popular hand-sanitizers, soaps, toothpastes, deodorants, cosmetics, clothing, and children’s toys. Yet a mounting body of scientific evidence shows that the chemical is no more effective at killing germs than plain soap and water. And it may cause more harm than good.

While triclosan has been shown to kill most of the bacteria it encounters, both good and bad, bacteria that survive emerge stronger and thus harder to eradicate. Triclosan can also irritate skin and has been linked to higher rates of allergies and hay fever among children. Lab studies have found that triclosan can impair thyroid function, upset estrogen and testosterone levels, and promote problems that could interfere with fetal development.

Scientists have also grown critical of the chemical’s potential effects on the environment. Triclosan can now be found in rivers, streams, and the sewage sludge that’s often used to fertilize crops. It’s toxic to algae, phytoplankton, and other aquatic life. Its absorption by these organisms means it can spread through the food chain. Even consumers who avoid triclosan still risk exposure to the chemical.

Our exposure to triclosan is so widespread that it lurks not only in our soap, but in our own bodies. Studies have found traces of it in urine, breast milk, and umbilical cord blood.

While these effects are known, the U.S. government has failed to protect consumers from triclosan’s potential hazards. The Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) share responsibility for regulating the marketing claims companies make about products containing triclosan, but neither agency restricts use of the chemical in consumer products.

Although the federal government remains apathetic towards triclosan’s risks, momentum is building elsewhere to ban the chemical in consumer products. Food & Water Watch and Beyond Pesticides, along with other advocacy groups, submitted a petition to the FDA in July 2009 warning these products don’t prevent illness and have the potential to harm human health and the environment.

Last year, Rep. Ed Markey (D-MA)–who at the time served as the House Energy and Environment Subcommittee Chairman–sent letters to the EPA and FDA requesting information about the health and environmental impacts of the chemical. He also urged these agencies to ensure that products containing it live up to their claims of killing germs without adversely affecting human health. Later that year, Representatives Louise Slaughter (D-NY), Betty McCollum (D-MN), and Raul Grijalva (D-AZ) urged the FDA to ban triclosan altogether.

Recently, a class action lawsuit was brought against Dial Corporation, a leading manufacturer of products containing triclosan, for false claims that triclosan-containing products kill 99.9 percent of germs.

Ciba has pulled its EPA registrations for triclosan in some products, and Colgate Palmolive has even removed the chemical from its antibacterial “Softsoap” product line. While these developments are a positive step, they don’t go far enough.

In addition to banning triclosan, we need to ensure that a different, equally harmful chemical doesn’t replace it. Under current law, chemicals are innocent until proven guilty, constituting a failure to protect consumers and the planet from their potential dangers. We should use triclosan as an example of why we need to reform our regulation of toxic chemicals.