Attorneys general from Connecticut, New Jersey and Delaware have sent letters to 11 companies that make baby bottles and baby formula containers, asking them to stop using bisphenol A because they said it was potentially harmful to infants.

The Food & Drug Administration has tentatively concluded that BPA is safe based on a review of research, and some manufacturers have already said they would make BPA-free baby bottles.

But Connecticut Attorney General Richard Blumenthal criticized the FDA for declining to take action after a preliminary study last month drew a possible connection to BPA and risks of heart disease and diabetes.

"Unfortunately the federal agency, the Federal Food and Drug Administration, has been asleep at the switch, in fact resistant to respecting the scientific evidence that grave harm can result in use of this product," Blumenthal said.

Scientists are at odds about the risks of BPA. A preliminary study released last month by the Journal of the American Medical Association suggested that adults exposed to higher amounts of the chemical were more likely to report having heart disease and diabetes. The study doesn't provide proof, although its authors said the results deserve scientific follow-up.

Michael Herndon, an FDA spokesman, said Monday that the agency is continuing to evaluate its risk assessment.

More than 90 per cent of Americans have traces of BPA in their bodies, but the FDA says the levels of exposure are too low to pose a health risk, even for infants and children. Other scientists, however, say BPA has been shown to affect the human body even at low levels. The scientific debate about the chemical could last for years.

In the letters, Blumenthal cites studies that indicate BPA can attach to food in heated containers. "The preventable release of a toxic chemical directly into the food we eat is unconscionable and intolerable," he wrote.

Letters were sent Friday to baby bottle manufacturers Avent America Inc., Disney First Years, Gerber, Handicraft Co., Playtex Products Inc. and Evenflo Co., and formula makers Abbott, Mead Johnson, PBM Products, Nature's One and Wyeth.

"Unfortunately the FDA has refused to do anything about it," Blumenthal said Monday. "We're asking the 11 manufacturers to do so voluntarily."

Jay Highman, president and CEO of Nature's One, who said his company doesn't sell its products in containers that have the chemical, hadn't received the letter by Monday.

Highman said the containers for his company's dry formulas are BPA-free and only the plastic lids have small traces of the substance. Because the lid is discarded before the formula is heated, there is very little chance the chemical will migrate into it, he added.

Shannon Jenest, a spokesperson for Philips Avent, parent of Avent America, said the company has not seen the letter and plans to review it carefully upon receipt.

Wal-Mart, Toys 'R' Us phase out products containing BPA

Several states are considering restricting BPA use, and some manufacturers have begun promoting BPA-free baby bottles. St. Louis-based Handicraft, maker of Dr. Brown's baby bottles, says on its website that its newest bottles do not contain BPA and urges consumers to check its products for symbols that identify bottles that don't contain the chemical. A message was left with the company seeking comment Monday.

Some U.S. stores, such as Wal-Mart Stores Inc. and Toys "R" Us, have already said they're phasing out products that contain BPA. The European Union has said BPA-containing products are safe, but Canada's government has proposed banning the sale of baby bottles with BPA as a precaution.

BPA is used in lightweight, durable plastics. Products include some baby bottles, sippy cups and reusable food and drink containers, such as reusable sports water bottles, Tupperware, compact discs, DVDs, eyeglass lenses and sports safety goggles and helmets. BPA is also in epoxy resins used to make paints, adhesives and canned food liners.

Animal studies have linked BPA with breast, prostate and reproductive system abnormalities and some cancers, but experts disagree on whether it poses health risks for humans.

The FDA's advice for consumers who want to reduce exposure includes avoiding plastic containers imprinted with the recycling number 7, as many of those contain BPA, and avoid warming food in such containers, the FDA said.