Some of the nation's largest child-product companies, including Johnson & Johnson, Proctor and Gamble and Kimberly Clark, are the target of a nationwide class-action lawsuit by parents after a study revealed that many of the companies' products contain questionable chemicals.

The suit, filed March 19 in U.S. District Court in Chicago, will represent parents or other consumers who purchased any of an extensive list of products, if the court certifies the action, according to law firm Hagens Berman Sobol Shapiro.

The findings were part of a study conducted by nonprofit, The Campaign for Safe Cosmetics, which tested commonly used baby products and found amounts of carcinogens such as formaldehyde and 1,4-dioxane. According to the report, manufacturers say the levels of the potentially cancer-causing toxins are so small that they do not pose a risk to the public, and are within government guidelines.

The defendants include Johnson & Johnson Consumer Companies, Gerber Products Company, The Proctor and Gamble Company, Kimberly-Clark Corporation, Expanscience Laboratories Inc. doing business as Mustela, and Limited Brands Inc.