A federal government panel reviewing phthalates is raising questions about the safety of a plasticizer commonly used in PVC medical devices. However, the group gave a clean bill of health to a sister chemical used in toys. The long-awaited preliminary report from the National Toxicology Program agrees with a report by former Surgeon General C. Everett Koop that diisononyl phthalate (DINP) is safe as a softening agent in chew toys.
But the Dec. 21 NTP statement said the panel of scientists was not able to reach any conclusions about di(2-ethylhexyl) phthalate (DEHP) during a three-day meeting that concluded Dec. 17. The group will need to reconvene to draw conclusions about DEHP and five other phthalates.
The panel said it had questions about particular medical applications, like repeated blood transfusions for infants. But John Bucher, deputy director of the environmental toxicology program at National Institute of Environmental Health Sciences in Research Triangle Park, N.C., said people exposed to phthalates intravenously from medical devices seem to be at less risk than those exposed orally. That's because intravenous exposure converts DEHP to its toxic by-product much more slowly, he said.
"It was clear that laboratory animal studies of DEHP have shown it to induce both fetal malformations and adverse effects on the reproductive systems," the report noted.
The panel could come back and say DEHP is safe, it is not safe, or that it is safe but exposures should not go any higher, Bucher said.
Marian Stanley, director of the Phthalate Esters Panel of the Chemical Manufacturers Association, said the NTP panel has a lot of questions, because there is a lot of data to sift through.
"I don't read it that they have serious questions," she said. "I think what they are wrestling with here is, as a scientist, you always want to know more."
Both the CMA panel and Health Care Without Harm, which is pushing for the reduction of PVC in medical devices, attended the NTP's North Carolina meeting and issued statements Dec. 17, several days before the NTP statement came out.
HCWH's statement said NTP confirmed that DEHP is hazardous to people, and co-coordinator Charlotte Brody said that "the direction [NTP] is going in is to express concern about exposure to DEHP in food and medical devices."
On DINP, Bucher said panel is firm in its conclusion. Its report said that "available research and testing data make it unlikely that current estimated exposure levels constitute a risk to human reproduction or development."