Government toxicologists have reiterated safety concerns about a chemical used in baby bottles and food containers, just weeks after the Food and Drug Administration declared the substance safe.

A report issued Wednesday said there is "some concern" that bisphenol A can cause developmental problems in the brain and hormonal systems of infants and children.

The conclusion from the National Toxicology Program repeats initial findings issued in April. The group — which includes scientists from the National Institutes of Health and other agencies — said bisphenol's risks to humans cannot be ruled out, but acknowledged its concerns are based on the findings of studies on animals.

The American Chemistry Council, which represents plastics manufacturers, stressed that studies from animals provide "limited and inconclusive evidence." The group has spent the last year defending the safety of bisphenol from new concerns about the risks of plastics to children.

Bisphenol is a plastic-hardening chemical used to seal canned food and make baby bottles. After more than a year of complaints from consumer and parent groups, the FDA has agreed to revisit the chemical's safety. The agency last month said the trace amounts that leach out of food containers are not a threat to children or adults.

But the toxicology group said that may not be true.

"More research is clearly needed to understand exactly how these findings relate to human health and development," said Michael Shelby, who directed the group's report. "But at this point we can't dismiss the possibility that the effects we're seeing in animals may occur in humans."

Shelby's group did back away from one issue raised in its draft report. While the group said in April there was "some concern" the chemical could speed up puberty in girls, the final report states there is now only "minimal concern" about those risks.

The National Toxicology Program ranks its conclusions about chemical risks on a five-tiered scale ranging from "negligible concern" to "serious concern."

Shelby said it is too early to recommend changes in what consumers buy and eat, but he added that parents who are concerned can avoid buying food containers made from bisphenol.

Several major retailers — including Wal-Mart Stores Inc. and Toys "R" Us Inc. — have said they would stop selling baby bottles made with the chemical next year. And smaller companies like Eveflo and BornFree have ramped up production of glass baby bottles as a bisphenol-free alternative.

Canada has said it intends to ban the use of the chemical in baby bottles, and state and federal lawmakers have introduced legislation to ban bisphenol in U.S. children's products.

More than 6 billion pounds of bisphenol are produced in the U.S. each year by Dow Chemical, Bayer AG and other manufacturers.