The National Research Council Monday reaffirmed that styrene - the key chemical component of foam cups and other food service items - may cause cancer in people.
A panel of 10 experts in medicine, chemistry and toxicology used a rather stilted definition, "reasonably anticipated to be a human carcinogen," to uphold the same finding from three years ago by the National Toxicology Program in its 12th Report on Carcinogens.
"I think it's important to keep in mind that this is a hazard assessment," said Dr. Jane Henney, who chaired the research council's committee of experts.
"Our report says this chemical could be a problem, but a full risk-assessment on dose, exposure, quantification and further characterization of the risk would need to be done before one would think about regulation in this area," added Henney, who headed the U.S. Food and Drug Administration during the Clinton administration.
Henney said her panel's conclusion-"reasonably anticipated to be a human carcinogen" - means there is scientific evidence suggesting that styrene causes cancer, but that there may be "alternative explanations, such as chance, bias or confounding factors," according to the report.
Another definition - "known to be a carcinogen," sets a much higher bar because it states overwhelming scientific evidence and leaves no element of doubt. Neither the research council nor the toxicology program used that definition.
The National Toxicology Program is part of the National Institutes of Health. The National Research Council is a major policy body and division of the National Academies, which includes the Institute of Medicine, the National Academy of Science and the National Academy of Engineering.
Styrene is a widely used compound in resins and plastics, but is best known to the public as the polymer polystyrene, which is widely used in plastic foam products.
For decades, industry leaders have insisted that styrene-based products, especially those used in food service, are safe.
On Long Island, the council's announcement was met with applause from advocates pushing for a ban of styrene-based products.
"Styrene is an endocrine disrupter and one of the chemicals we are concerned about in the breast cancer community," said Laura Weinberg, president of the Great Neck Breast Cancer Coalition.
An endocrine disrupter, Weinberg said, is any chemical that mimics estrogen and drives the growth of cancers.
Other groups also have been trying to eliminate plastic foam from contact with the food supply, especially warm liquids, which they say causes styrene to leach out.
"Since 2000 we have been actively working on plastics issues and styrene has been at the top of the list, along with PVC," said Patti Wood, executive director of Grassroots Enviromental Education, a Port Washington, N.Y., health advocacy organization.
Styrene is not only a possible carcinogen, she said, but plastic foam products have been cited for polluting waterways and the national landscape because it does not easily disintegrate.
"The fact that it is used so ubiquitously as a material for food and drink made us focus on it, especially where children are being exposed every single day. So this is good news," Wood said Monday of the panel's decision.