WASHINGTON, Oct. 25, 2016 - The International Agency for Research on Cancer’s latest report, which looks at the cancer-causing potential of five chemicals, received swift criticism from the group that represents U.S. pesticide manufacturers.

IARC published a summary in The Lancet yesterday of its review of pentachlorophenol (PCP), 2,4,6-trichlorophenol (TCP), aldrin, dieldrin, and 3,3′,4,4′-tetrachloroazobenzene (TCAB). The first four have been used as pesticides, but are no longer registered by EPA. TCAB “is formed during the production and degradation of chloroanilide herbicides,” the Lancet news item said.

IARC categorized dieldrin, aldrin and TCAB as “probably carcinogenic to humans” (Group 2A in its classification framework); pentachlorophenol as “carcinogenic to humans” (Group 1), and TCP as “possibly carcinogenic to humans” (Group 2B).

But CropLife America, a frequent critic of the World Health Organization agency, raised questions about the report shortly after it appeared. CLA’s Janet Collins, senior vice president of science and regulatory affairs, said IARC had failed to put its findings in the proper perspective.

“When communicating with the general public about any potential health concerns in its environment, it is important that organizations characterize hazard with perspective regarding actual exposure and real human health risk, which IARC’s communication in Lancet fails to do,” Collins said in a statement posted on CLA’s website.

In an interview today, Collins elaborated on that position, but also questioned why IARC even evaluated the chemicals in the first place. All uses of aldrin and dieldrin in the United States, for example, have been banned since 1987.

“It begs the question: Why is IARC wasting time and resources and writing a press release?” Collins asked. “Our question continues to be: Why are we doing this?”

Pentachlorophenol “has been widely used as a wood preservative and insecticide, but its production and use are now restricted,” IARC said in The Lancet. “General population exposure can occur from treated wood products, contaminated food and water, and incinerator emissions.”

CropLife has been particularly outspoken in its criticism of IARC since March 2015, when the agency released a monograph – the official record of its working groups’ deliberations – concluding that glyphosate, the active ingredient in Roundup, is probably a human carcinogen. A spokeswoman for CLA said Collins wants to be clear that CLA's concerns are about IARC's monograph program, not about IARC itself.

The IARC report triggered a wave of regulatory reviews around the world, most of which found it was unlikely to cause cancer in humans. An EPA Scientific Advisory Panel (SAP) was originally supposed to meet last week to review an agency paper that found glyphosate is not likely to be carcinogenic, but one of the panel members withdrew, and now EPA hopes to reschedule the meeting for December.

Attempts to reach IARC for comment on Tuesday were not successful.

In another development concerning IARC and glyphosate, House Science Committee Chairman Lamar Smith, R-Texas, told EPA Administrator Gina McCarthy he “is concerned that the EPA will not evaluate glyphosate based on sound science.”

In a letter, Smith cited documents the committee obtained that appear to contradict McCarthy’s testimony to the committee about the extent of EPA involvement in the IARC glyphosate review.

“From documents it has obtained, the committee has determined unequivocally” that two EPA employees, Peter P. Egeghy in the Office of Research and Development (ORD), and Matthew T. Martin of ORD’s National Center for Computational Toxicology, “played a much larger role in the IARC’s assessment of glyphosate than you or any EPA official has previously admitted to the committee,” Smith said.

He asked McCarthy to make those two employees, as well as Jim Jones, assistant administrator for the Office of Chemical Safety and Pollution Prevention, available for interviews no later than 5 p.m. on Nov. 1.

Smith also raised questions about the inclusion on the glyphosate SAP of Kenneth Portier, an American Cancer Society statistician and the brother of toxicologist Christopher Portier, who participated in IARC’s glyphosate report.

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Christopher Portier contacted Jones after EPA’s initial Cancer Assessment Review Committee (CARC) report on glyphosate was accidentally posted online in May. That report, which was online for a few days before being removed, concluded glyphosate was not likely to be a human carcinogen.

On May 4, 2016, Portier forwarded Jones a Politico article reporting on the posting of the CARC study “and the implications it may have for a European Union decision on glyphosate,” Smith said in his letter. “Understanding Portier’s urgency in the matter, … Jones forwarded Portier’s email on to his EPA subordinates stating, ‘We need to think about a statement that goes beyond saying our assessment is not final. Looks like it will be used to inform other government decisions.’

Given Portiers apparent efforts to use IARC to influence global policy decisions and his desire to discredit the (European Food Safety Authority) glyphosate study, it is reasonable to assume that Assistant Administrator Jones acted to assist him and IARC by publically (sic) downplaying scientific analysis conducted by EPA,” Smith said. 

Also on Tuesday, Reuters reported that IARC officials were discouraging members of its glyphosate panel from releasing documents related to the glyphosate review.

IARC “does not encourage participants to retain working drafts or documents after the monograph has been published,” according to an email from IARC’s Kate Guyton to six members of the glyphosate panel, Reuters reported.

(The story was updated on Oct. 26 to add CLA spokeswoman's comment about IARC monograph program in ninth paragraph.)


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