Water bottles made with the controversial carbonate plastic bisphenol A, or BPA

Q&A: How Am I Affected?
Where is BPA found?

The National Toxicology Program says the main source of human exposure to bisphenol A, or BPA, is the tiny amounts that leach from Nalgene-type polycarbonate water bottles and from metal cans — that could include canned vegetables and fruits — lined with an epoxy resin that contains BPA. The chemical is also found in baby bottles, tableware and food storage containers.

Does BPA cause health problems?

Studies about the effects of BPA have been conflicting. Some animal studies have suggested a link between BPA and effects on the brain, behavior and the prostate gland — and raised concerns about the effects of exposure on the developing fetus and young children. But there are no conclusive studies linking BPA to human health problems.
It's also unclear what determines how much leaching occurs. It may depend on the temperature of the liquid or bottle or how the plastic is reused.

What should I avoid?

To minimize exposure to BPA, the National Toxicology Program recommends that people avoid microwaving plastic food containers or washing them in the dishwasher with harsh detergents. Repeated exposure to high temperatures and harsh cleaning agents can deteriorate the plastic and release BPA.

Additionally, some sources, such as NTP, have advised consumers to avoid hard, clear plastic containers with the No. 7 on the bottom. While the chemical industry maintains that plastic bottles contain little BPA and leach trace amounts too low to be harmful to humans, some companies have voluntarily elected to sell BPA-free products. Nalgene sells BPA-free water bottles, and retailers such as Toys R Us and Wal-Mart offer baby bottles and other children's products that are BPA-free.

— Kathleen Masterson