A federal panel of scientists concluded Wednesday that an estrogen-like compound in plastic could be posing some risk to the brain development of babies and children.
Bisphenol A, or BPA, is found in low levels in virtually every human body. A component of polycarbonate plastic, it can leach from baby bottles and other hard plastic beverage containers, food can linings and other consumer products.
Culminating months of scientific debate, the decision by the 12 advisors of the Center for the Evaluation of Risks to Human Reproduction -- part of the National Institutes of Health -- is the first official, government action related to the chemical. Their recommendation will be reviewed for a federal report that could lead to regulations restricting one of the most used chemicals.
The scientists ranked their concerns about BPA, concluding they had "some concern" about neurological and behavioral effects in fetuses, infants and children, but "minimal" or "negligible" concern about reproductive effects. The findings put the panel roughly in the middle -- between the chemical industry, which has long said there is no evidence of danger to humans, and the environmental activists and scientists who say it is probably harming people.
Steve Hentges of the American Chemistry Council's polycarbonate division said the panel's report was "strong reassurance to consumers" that products containing BPA are safe.
Frederick vom Saal, a University of Missouri-Columbia reproductive toxicologist who has conducted studies on BPA, was disappointed that the panel did not rank the risk higher. But, he said, "the panel is now on record saying there are human health concerns."
The panel reviewed about 500 animal studies, many of which reported that the estrogen-like chemical alters various functions and parts of the body. Some have found altered brain development, precancerous changes in prostates and mammary glands, low sperm counts, and damage to the uterus. Plastics industry representatives say the lab experiments are inconclusive and flawed.
No study has looked for effects in people exposed to the plastic products, which have contained BPA for 50 years.
The panel had five rankings for its findings: negligible concern, minimal concern, some concern, concern and severe concern. In its conclusion, the level was "some concern."
For fetuses, pregnant women, infants and children, the panel reported there was "some concern that exposure to bisphenol A causes neural and behavioral effects." In studies of newborn animals, low doses of BPA cause structural changes in the brain that trigger learning deficits and hyperactivity.
For fetuses and children, they said there was "minimal concern" that BPA harms the prostate gland and causes premature puberty, and "negligible concern" that it causes birth defects.
For adults, they reported "negligible concern about adverse reproductive effects."
John Bucher, associate director of the National Toxicology Program, which oversees the reproductive health center, said the panel gave the most weight to neurological effects in children, infants and fetuses because studies consistently have found those effects when newborn animals are exposed to low doses similar to what people encounter. Bucher said that because the science remains uncertain, it is up to individuals to decide whether they want to avoid products containing BPA.
"To me, we're still in that stage of scratching around at the surface of this issue," he said.
Last week, Vom Saal and 37 other scientists published a consensus statement in a scientific journal concluding it was likely that BPA affected humans, even at low doses. The federal panel's findings were not as strongly worded.
Environmentalists lambasted the panel, saying it had minimized the risks and ignored important research.
"Only the chemical industry agrees with the decision that BPA has little or no human health risks. That by itself should speak volumes about the corrupted process endorsed by the panel today," said Dr. Anila Jacob of the Environmental Working Group.
In March, the Los Angeles Times reported that the panel's preliminary report on BPA was drafted by a private consulting firm with financial ties to the chemical industry. The National Toxicology Program fired the company but ruled that the report was unbiased.
Part of the reason the panel ranked the risks as less serious than did the other group of scientists is that the panel rejected several dozen animal studies that found reproductive effects. In those studies, animals were exposed through injections, rather than through their diet. The decision to reject the studies has been controversial with toxicologists.
Two of the panel's scientists are from private pharmaceutical companies, six from universities and two from federal agencies. It was chaired by Robert Chapin, head of developmental toxicology at Pfizer Inc. None has expertise in BPA.
Their recommendations will go to the National Toxicology Program, the federal scientists who help regulators mold policy about toxic substances. Officials there will send their report out for review by other scientists before deciding whether to declare BPA toxic to humans. Bucher said he would also update it with the consensus statement and studies published last week.
The final report could trigger a review of BPA by California officials under Proposition 65, which requires warnings on consumer products that pose a risk of cancer or reproductive harm.