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A DEHP Flashback

August 31, 2015 | A version of this story appeared in Volume 93, Issue 34

“Chemical Labels Spark Clash” sparked a flashback to 1978 for me (C&EN, May 18, page 23). That year, I was assigned to do environmental impact and regulatory jeopardy assessments of the phthalates produced by the world’s largest manufacturer of those compounds—­Monsanto.

After a few months’ work, it was obvious to me that a national conference was needed to deal with that class of compounds, which comprises at least 30 different commercial products with a wide range of environmental and toxicological properties. The Toxic Substances Control Act, the Clean Water Act (CWA), and the Federal Food, Drug & Cosmetic Act were among the laws to which phthalates were subject. Environmental ubiquity and toxicity were major concerns at that time.

Di(2-ethylhexyl) phthalate (DEHP), which Monsanto no longer produced in 1978, appeared to be the phthalate that EPA intended to use in setting CWA regulations. Because the effective concentration (EC50) for inhibition of reproduction of Daphnia magna by DEHP was far below DEHP levels being reported in most aquatic ecosystems, the possibility for zero-discharge regulations under CWA for all phthalates was a serious threat to the entire vinyl plasticizer industry.

When I proposed that Monsanto take the initiative among members of the Chemical Manufacturers Association (CMA) in calling for a national conference to include industry, government, and ­academic participants to address that issue and others like it, resistance by the head of the environmental management staff of the plasticizers business group killed the idea. Head of that staff was Dr. Clayton Callis, soon-to-be-elected president of ACS. His objection was primarily that “it will just draw attention to our products.”

I eventually left Monsanto after a brief stint as chairman of the Human Health Research Committee of the CMA Phthalate Esters Panel. This was during the months following the November 1979 release of the National Toxicology Program (NTP) bioassay of DEHP that found “clear evidence of carcinogenicity in both sexes of rats and mice.” I joined EPA as senior scientist in the Risk Assessment Division of the Office of Toxic Substances in May 1981.

The National Conference on Phthalate Esters, sponsored by NTP, was held in June 1981.

Listing phthalates (as a group) with arsenic, benzene, cadmium, formaldehyde, mercury, and hexavalent chromium, among others, in a proposed warning label that reads, “This product can expose you to phthalates, a chemical known to the State of California to cause cancer,” must have my old friend Clay Callis, as they say, churning up the graveyard.

J. William Hirzy
Washington, D.C.



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