WASHINGTON - The federal government said Monday it has no evidence that antibacterial chemicals used in liquid soaps and washes help prevent the spread of germs, and it is reviewing research suggesting they may pose health risks.

Regulators at the Food and Drug Administration said they are revisiting the safety of chemicals such as triclosan in light of recent studies suggesting the substances can interfere with hormone levels and spur the growth of drug-resistant bacteria.

The government's preliminary ruling lends new support to outside researchers who have long argued that the chemicals are, at best, ineffective and at worst, a threat to public health.

"The FDA is finally making a judgment call here and asking industry to show us that these products are better than soap and water, and the data don't substantiate that," said Stuart Levy of Tufts University School of Medicine.

Under a proposed rule released Monday, the agency will require manufacturers to prove that antibacterial soaps and body washes are safe and more effective than plain soap and water. Products that are not shown to be safe and effective by late 2016 would have to be reformulated, relabeled or removed from the market.

A spokesman for the cleaning product industry did not immediately respond to a request for comment from The Associated Press.

The FDA ruling does not apply to hand sanitizers, most of which use alcohol rather than antibacterial chemicals.

The agency will accept data from companies and researchers for one year before beginning to finalize the rule.

The FDA proposal comes more than 40 years after the agency was first tasked with evaluating triclosan, triclocarban and similar ingredients. Ultimately, 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 triclosan. The chemical is found in an estimated 75 percent of antibacterial 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.

While the FDA ruling only applies to liquid hygiene cleaners, it has implications for a broader $1 billion industry that includes thousands of antibacterial products, including kitchen knives, toys, pacifiers and toothpaste. Over the last 20 years, companies have added triclosan and other cleaners to thousands of household products, touting their germ-killing benefits.

The FDA was tasked with confirming those benefits in 1972, as part of a law designed to set guidelines for dozens of common antibacterial cleaners. The agency published a preliminary draft of its findings in 1978, but never finalized the results until Monday.