[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]

You may never have heard of bisphenol A, also known as BPA, but odds are you're carrying it around in your body right now. Researchers tested more than 2000 people between the ages of six and 85.  And 93 percent of them tested positive for BPA, according to the U.S. Centers for Disease Control and Prevention.

Why should you care? Well, BPA is a component of the polycarbonate plastic in eyeglass lenses and DVDs among other things.  And high levels of it have been linked to heart disease, diabetes and liver failure in humans, according to the Journal of the American Medical Association.

In fact, the National Toxicology Program warns that BPA may cause babies to develop abnormally. The Canadian government went so far as to ban it in baby bottles as well as listing it as a toxic substance. But the U.S. Food and Drug Administration and the Environmental Protection Agency maintain that BPA is perfectly safe.

Congress, for its part, is considering banning the substance in some products. In the meantime, note that items made from BPA are typically marked with a number seven. These plastics should never be microwaved or exposed to hot liquids—heat can dissolve BPA into what you’re drinking.   Better safe than sorry.

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