5 Toxins to avoid and Why: BPA

From CNN's Toxic America series

BPA - Bisphenol A

What it does: BPA is a building block of a lightweight, clear, heat-resistant and almost unbreakable plastic called polycarbonate. It's also used in epoxy resins.

Where it's found: Water bottles, baby bottles, reusable food containers, plastic tableware, infant feeding cups, linings of infant formula cans and other cans, jar lids, CDs, electrical and electronic equipment, dental sealants.

How we're exposed: Eating food or drinking liquids stored in containers containing BPA. Infants and small children may also be exposed from hand to mouth contact with materials containing BPA. BPA also migrates from dental sealants into patients' mouths. Fetuses are exposed in the womb by their mothers. Almost everyone has been exposed. The Centers for Disease Control and Prevention found BPA in the urine of 93 percent of the people it tested.

Health effects: The American Chemistry Council, an industry trade group, says exposure is so low there are no ill health effects. A new five-year Kaiser Permanente study of Chinese factory workers found higher BPA exposure linked to reduced male sexual function. This research joins a growing body of research on animals that suggests BPA poses a potential cancer risk and may mimic the female hormone estrogen and disrupt the extremely sensitive chemical signals in the body called the endocrine system. According to the Food and Drug Administration, these studies suggest BPA could affect "the brain, behavior and prostate gland in fetuses, infants and young children."

Regulation: BPA is an Environmental Protection Agency "chemical of concern," one of five substances the agency has targeted for increased scrutiny and potential new regulation. (The others are phthalates, short-chain chlorinated paraffins, PBDEs, and perfluorinated chemicals including PFOA.)

The Food and Drug Administration allows BPA in flexible food packaging.

What you can do to reduce exposure: Buy stainless steel bottles and glass food storage containers. If you buy plastic, check for the recycle number on the bottom. If there is a number 7, assume the container contains BPA unless it explicitly says otherwise. Switch to fresh or frozen vegetables instead of canned. Other precautions include not microwaving or putting hot liquids in BPA plastic containers and throwing away baby bottles and feeding cups that are scratched.

Read more of this great toxins 'primer' at CNN