Dozens of environmental health organizations in the United States and Canada are calling for an immediate moratorium on the use of a chemical, bisphenol A - or BPA - in food and beverage containers, including baby bottles. They say a new study found that, when exposed to heat, baby bottles release a chemical that, researchers say, has been linked to obesity, diabetes and developmental problems in lab animals. When bottles are used extensively over time, and when they're heated, higher levels of this chemical leach out, exposing young infants to elevated levels of this unnecessary toxic chemical," says Mike Shaade at the Center for Health Environment and Justice. BPA is used to make plastic in 95 percent of baby bottles now on the market. But it is up for debate whether it is harmful or not. BPA is already in most of us: the Centers for Disease Control and Prevention found BPA in the urine of 95 percent of people it tested. Dr. Maida Galvez is a pediatrician at Mount Sinai Hospital in New York City, who studies whether traces of BPA found in children's urine is harmful to them. "We know the animal studies raise concerns, but there aren't human studies showing effects yet ... so, when we don't have the evidence, what we recommend is that parents try to err on the side of caution," she says.