New research shows that a controversial chemical in plastic baby and water bottles, cups and food containers may be linked to heart disease and diabetes, prompting new fears about the ingredient. 

Bisphenol A (BPA), the subject of much scientific debate this year over its potential health effects, was associated with type 2 diabetes, angina, coronary heart disease and heart attack in adults with elevated levels of the chemical. The results, published in the Journal of the American Medical Association, are based on urine samples from 1,455 participants in a government health survey.

"The findings … challenge the safety of BPA," says an editorial that accompanies the study. The authors, biologists Frederick vom Saal and John Peterson Myers, blast the Food and Drug Administration (FDA) for deeming the chemical as "safe" and write that federal regulators should follow the lead of Canada, which has banned baby bottles made with BPA.

The FDA said in a draft report last month that BPA is safe at current levels of exposure — a call that contrasted with an April report by the National Toxicology Program citing "some concern" about the chemical. An FDA panel reviewed the agency's draft report today, and Iowa Sen. Charles Grassley asked Commissioner Andrew von Eschenbach to explain the criteria FDA is using to determine which studies it's taking into account in its safety ruling.

"A margin of safety exists that is adequate to protect consumers, including infants and children, at the current levels of exposure," FDA scientist Laura Tarantino told the panel, according to the Associated Press.

An FDA spokeswoman had no immediate response to how the agency would address Grassley's request.

An industry group dismissed the new findings, insisting that the study "is not capable of establishing a cause and effect relationship between bisphenol A and these health effects" because the onset of the diseases would have occurred before the urine samples were taken.

“This new study cannot support a conclusion that bisphenol A causes any disease,” Steven Hentges of the American Chemistry Council said in a statement. “The weight of scientific evidence continues to support the conclusion of governments worldwide that bisphenol A is not a significant health concern at the trace levels present in some consumer products.”

Most Americans are likely exposed to more than the 50 micrograms-per-kilogram daily dose of BPA that federal environmental regulators consider safe, according to the JAMA study. Previous animal studies have associated BPA with obesity, liver problems and thyroid dysfunction, and human and animal research has shown that the chemical mimics estrogens. Some parents started feeding their babies with glass bottles this year after word spread about BPA's possible health effects.

States including California, Maryland, Minnesota and Michigan may bar the chemical in children's products.