On Vinyl and Phthalates

I am writing on behalf of the Phthalate Esters Panel of the American Chemistry Council to point out the inaccuracies about phthalates contained in a letter to the editor written by Mr. Mark E. Kelley III [

EBN

Vol. 10, No. 11]. I request that you publish this letter so that your readers will not be left with an inaccurate impression about phthalates, ingredients that impart the critical quality of flexibility to PVC.

Contrary to assertions in Mr. Kelley’s letter, phthalates are NOT known to cause cancer in humans. One phthalate formerly had been designated as a “probable” carcinogen based on studies in rodents. In February 2000, however, the International Agency for Research on Cancer (IARC) changed the classification of that phthalate from a probable carcinogen to “not classifiable” as to carcinogenicity in humans. This was done based on IARC’s conclusion that the mechanism by which the phthalate causes cancer in rodents is not relevant to humans.

Phthalates are NOT bioaccumulative. Phthalates are readily metabolized by biological organisms such as fish and mammals. Humans exposed to phthalates metabolize them to by-products that are rapidly excreted, predominantly within 24 hours of ingestion. Because phthalates are excreted rather than retained by any organism for any significant period of time, phthalates do NOT biomagnify, or increase in concentration, as one moves up the food chain.

Mr. Kelley alleges that phthalates are endocrine disruptors. This is difficult to address since there are currently no agreed upon, validated tests or defined endpoints with which to identify endocrine disruptors.

The important question is whether phthalates pose reproductive risks to humans as a consequence of endocrine disruption or any other process. The Panel has conducted extensive research in this area and has shared the results of this research with government bodies around the world. Following a recent review of this and other research, the National Toxicology Program’s Center for the Evaluation of Risks to Human Reproduction expressed minimal to negligible concern for reproductive and developmental effects in humans from expected exposures to most phthalates. Where some few areas of concern were identified, the phthalate exposures were, nevertheless, well below levels at which even minor effects have been observed in animals.

A special expert advisory panel appointed by the Consumer Product Safety Commission to assess the safety of use of DINP (one of the most widely used phthalates) in consumer products issued a report in June of this year. The panel stated that “humans do not receive DINP doses from DINP-containing consumer products that are plausibly associated with a significant increase in cancer risk.” Additionally, the panel stated, “The risk to reproductive and developmental processes in humans due to DINP exposure is extremely low to nonexistent.”

I encourage your readers to contact the Panel for any information they might need regarding phthalates (Marian Stanley, Panel Manager, 703/741-5623) or to visit the Panel’s Web site at

www.phthalates.org.

Courtney M. Price

Vice President, CHEMSTAR

American Chemistry Council

Arlington, Virginia

Editors’ response:

Ms. Price may be understating the extent of concern surrounding the use of phthalate plasticizers in PVC products. The January 28 issue of Plastics News

reports that Health Canada (roughly equivalent to the U.S. Food & Drug Administration) is reviewing a technical report written by a special advisory panel and expects to recommend significant reductions in the use of di (2-ethylhexyl) phthalate—DEHP—in healthcare products. For example, the report recommends that healthcare products containing DEHP not be used with newborns or males before puberty.

Scientific studies support both sides of the phthalates issue. The precautionary approach is to reduce or eliminate use of such compounds where substitutes with established safety records can be found.