A new study has revealed that some foods marketed to kids contain high levels of the potentially dangerous chemical bisphenol A, or BPA, which is used in the epoxy lining of metal cans. This concerns many health advocates, because children are believed to be most susceptible to the effects of BPA. Researchers at the nonprofit Breast Cancer Fund , which conducted the study, say BPA must be removed from food packaging, "especially in foods marketed to children." Manufacturers say there's no proof the compound can harm kids. Here, a brief guide:

What exactly is BPA?
BPA helps to make plastics stronger and more resistant to breaks, corrosion, and heat damage. The chemical is used in food containers, medical equipment, toys, paint, electronics, water bottles — even cash register receipts are coated with it. But BPA is also "known to mimic the hormone estrogen in the body and may interfere with the body's endocrine system," says Jennifer Warner at WebMD. Some health experts say they worry about the presence of any hormone-like substance in children's food.

Is BPA definitely unsafe?
The jury's still out. "The chemical has been linked to all sorts of reproductive and developmental problems, including cancers, diabetes, early, and attention deficit disorders," says Emily Sohn at Discovery News. Canada, France, Sweden, and other countries have banned its use in baby bottles, and other food and drink containers. But many manufacturers say BPA is perfectly safe. The dangers have never been proven in human studies — only animal and cell studies have been conducted. 

What kinds of kids' foods contain BPA?
Researchers from the Breast Cancer Fund found high levels of the chemical in canned foods like Campbell's "Toy Story" soups, Earth's Best "Elmo Noodlemania" soup, and Annie's Homegrown "Cheesy Ravioli." While the Environmental Protection Agency estimates that 50 parts per billion (ppb) a day is a safe exposure level, many of these foods contained much more than that in a single serving. Samples of Campbell's "Disney Princess" soup, for example, contained up to 148 ppb.

Sources: ABC News, Discovery News, WebMD