The US Food and Drug Administration will decide by March 31, 2012 whether to ban the chemical BPA in food packaging.
The agency's promise settles a lawsuit brought in August by the Natural Resources Defense Council. The environmental advocacy group sued, saying the FDA was purposefully delaying a decision on the chemical.
"It is discouraging that we had to ask the court to intervene just to get FDA to do its job," said Sarah Janssen, senior scientist with the NRDC. "The agency has been dragging its feet on making a decision about BPA for far too long."
FDA officials declined to comment.
The chemical, which mimics the hormone estrogen, is used to make hard clear plastic. It is found in the lining of most metal cans. It's also used to line most cash register receipts.
Trace amounts of BPA have been detected in the urine of 91 percent of Americans tested.
Manufacturers argue the chemical is safe for all use. But environmental groups have pushed for a ban, citing a growing number of studies that link the chemical to health problems.
In January 2010, the FDA announced that it had some concerns about the potential effects of BPA on the brain, behavior, and prostate gland in fetuses, infants and young children. The agency said it supported the industry's actions to stop producing baby bottles and infant feeding cups made with BPA for the US market.
The agency said it would facilitate the development of alternatives to BPA for the linings of infant formula cans and support efforts to replace BPA or minimize BPA levels in other food can linings.
Scientific studies have linked BPA to diseases including cancer, diabetes, obesity and hyperactivity.
It has been banned for use in baby bottles in Canada and several states, including Wisconsin.
A three-year Journal Sentinel investigation found that FDA regulators deferred to industry scientists in the agency's original assessment of the chemical as safe, allowing scientists paid by chemical makers to write entire sections of the agency review.
The newspaper also found that the FDA originally relied on two studies to determine BPA's safety -- both of which were funded by the advocacy group that represents the chemical makers.
Under pressure by health groups, the agency reopened its assessment and heightened its concern in January 2010. The FDA promised a more definitive answer on the chemical's safety by June 2011, but none has been posted.
Meanwhile, a study cautions women to avoid BPA to minimize their chances of breast cancer. The report was issued by the Institute of Medicine, part of the National Academy of Sciences. The sole sponsor was a breast cancer advocacy group, Susan G. Komen for the Cure, which requested the report and spent $1 million on it.
The study said there was a "biological plausibility" that BPA is linked to breast cancer.
Scientists can see a mechanism in animals by which certain substances, including BPA, might cause breast cancer, but there is not enough information to assess the risk in humans, the study said.