Four Ohio parents have filed a federal lawsuit against makers of baby bottles, claiming the companies failed to adequately disclose risks associated with the chemical bisphenol A.

The complaint filed last week in U.S. District Court alleges the companies knew that a chemical known as bisphenol A was associated with health problems. It cites scientific studies that conclude BPA, as the chemical is also known, seeps from bottles and sippy-cups into liquid.

Seeking to ease public concerns about any health hazards, a federal health official told a House energy and commerce subcommittee last week that the level of BPA exposure a person would receive from a plastic bottle is safe.

Many of the studies that have reported higher levels were conducted under unrealistic conditions, said Dr. Norris Alderson, the Food and Drug Administration's associate commissioner for science.

"Although our review is ongoing, there's no reason to recommend consumers stop using products with [bisphenol A]," he said.

The lawsuit, which seeks class-action status, names five companies: Vandalia, Ohio-based Evenflo Co., Illinois-based Avent America Inc., Missouri-based Handicraft Co., Connecticut-based Playtex Products Inc., and Swiss company Gerber Novartis. The plaintiffs are seeking an unspecified amount of damages.

Until recently, Health Canada had long maintained the chemical used in the manufacture of hard plastic water bottles, DVDs, CDs and liners in cans did not pose a risk to human health.

But on April 18, Health Minister Tony Clement announced a ban on the import and sale of polycarbonate baby bottles containing bisphenol A.

Handicraft spokesman Steve Richardson declined comment Wednesday. Playtex spokeswoman Jacqueline Burwitz said the company doesn't comment on pending legal matters. A Gerber spokeswoman referred questions to Switzerland-based Nestle SA, which acquired Gerber Products Co. from Novartis AG last year.

Messages for Nestle, Evenflo and Avent were not immediately returned. Messages also were left for the plaintiffs' attorney.

The U.S. government's National Toxicology Program said in April that there is "some concern" about BPA from experiments on rats that linked the chemical to changes in behavior and the brain, early puberty and possibly precancerous changes in the prostate and breast. While such animal studies only provide "limited evidence" of risk, the draft report said a possible effect on humans "cannot be dismissed."

Wal-Mart, Toys "R" Us pull BPA bottles

That finding prompted Wal-Mart Stores Inc., the world's largest retailer, to pledge BPA-free bottles by early next year. Toys "R" Us also pledged to purge its shelves of BPA-containing bottles by year's end.

Bisphenol A is a ubiquitous chemical in household goods, including eyeglasses, food cans and CDs and DVDs. It also is found in dental sealants. More than six million pounds of bisphenol are produced in the U.S. each year by Dow Chemical Co., Bayer AG and other manufacturers.

The American Chemistry Council, a trade group representing chemical makers, says BPA is a well-known chemical and the fretting is unreasonable.

"If you look at the government assessments, they have been strong, uniform and clear, that at the levels to which consumers are exposed, BPA base materials do not pose a risk to consumers," said American Chemistry Council plastics director Stephen Russell.

Russell said he had not seen the lawsuit but noted decades of research indicates that day-to-day exposure is not a reason for concern.

An Arkansas woman filed a separate lawsuit last month against Playtex, claiming that BPA can be toxic even at low doses and the company has failed to adequately disclose that its products are formulated using the chemical. That lawsuit, filed in U.S. District Court in New Haven, Conn., also seeks class-action status.