From ScientificAmerican website:
Plastic (Not) Fantastic: Food Containers Leach a Potentially Harmful Chemical
Is bisphenol A, a major ingredient in many plastics, healthy for children and other living things?
By David Biello
Bisphenol A (BPA) is a ubiquitous compound in plastics. First synthesized in 1891, the chemical has become a key building block of plastics from polycarbonate to polyester; in the U.S. alone more than 2.3 billion pounds (1.04 million metric tons) of the stuff is manufactured annually.
BPA is routinely used to line cans to prevent corrosion and food contamination; it also makes plastic cups and baby and other bottles transparent and shatterproof. When the polycarbonate plastics and epoxy resins made from the chemical are exposed to hot liquids, BPA leaches out 55 times faster than it does under normal conditions, according to a new study by Scott Belcher, an endocrine biologist at the University of Cincinnati. "When we added boiling water [to bottles made from polycarbonate] and allowed it to cool, the rate [of leakage] was greatly increased," he says, to a level as high as 32 nanograms per hour.