FRIDAY, Oct. 29 (HealthDay News) -- Scented consumer products such as air fresheners, laundry detergents, deodorants and shampoos give off many chemicals, including some that are classified as toxic, but a new study finds that these chemicals often aren't listed on the products' labels.

U.S. researchers analyzed 25 commonly used scented products, and found that they emit an average of 17 chemicals each. Of the 133 chemicals detected in all the products, nearly one-quarter are classified as toxic or hazardous under at least one federal law.

More than one-third of the products emitted at least one chemical classified as a probable carcinogen by the U.S. Environmental Protection Agency.

But only one of the 133 chemicals emitted by these items was listed on a product label, and only two of the chemicals were publicly disclosed elsewhere.

Federal law doesn't require companies to disclose ingredients used in fragrances, even though a single fragrance can be a mixture of several hundred ingredients, according to lead author Anne Steinemann, a professor of civil and environmental engineering and of public affairs at the University of Washington in Seattle.

"We analyzed best-selling products, and about half of them made some claim about being green, organic or natural," Steinemann said in a university news release. "Surprisingly, the green products' emissions of hazardous chemicals were not significantly different from the other products."

The study was published in the Oct. 26 online edition of the journal Environmental Impact Assessment Review.

More information

The U.S. National Library of Medicine offers a household products database.