WEDNESDAY, Jan. 28 (HealthDay News) -- Bisphenol A, a controversial chemical used to harden plastics for consumer products such as baby bottles and food containers, appears to remain in the body much longer than thought, a new study says.

The finding suggests that exposure to BPA may come from many different sources, not just food products, or that the body doesn't metabolize the chemical as fast as has been thought, the researchers said.

The finding also adds to the controversy about the health consequences of exposure to the chemical, which some studies have linked to cancer, diabetes, heart disease and developmental problems in children.

"What this study shows is that either we are getting exposed to a lot more BPA than we thought, or it's hanging around longer than we thought, or both," said lead researcher Dr. Richard W. Stahlhut, a postdoctoral fellow at the University of Rochester Medical Center's Environmental Health Sciences Center, in New York.

The U.S. Food and Drug Administration was criticized by some scientists -- including one of its own advisory panels -- after it said last August that BPA did not pose a health threat. By December, the agency had agreed to re-examine that earlier ruling.

For the new study, Stahlhut's team collected data on 1,469 people who participated in the U.S. Center for Disease Control and Prevention's National Health and Nutrition Examination Survey. The researchers looked at the amount of BPA in urine and the length of time the participants had been fasting before the urine sample was taken.

Conventional wisdom says food is the most common source of BPA, and the body clears the chemical fairly quickly. The researchers expected to see less BPA in those who fasted the longest, compared to those who had eaten recently.

But, the researchers found that the levels of BPA in people who had fasted the longest were only moderately lower than in those who had just eaten. BPA levels dropped about eight times more slowly than expected, the scientists said.

One possibility is that people are exposed to more BPA than can be found in food alone, Stahlhut said, citing tap water or house dust as other sources. The other possibility is that BPA gets "hung up" in fat cells in the body, he said.