The director of the UN International Agency for Research on Cancer rebutted criticism of his agency’s listing of glyphosate, the most widely used herbicide in the world, as probably carcinogenic to humans, saying the criticism included “repeated misrepresentations” of the IARC’s deliberations. In a letter to two Republican leaders of the House Science Committee, IARC director Christopher Wild said the group’s March 2015 classification of glyphosate was the consensus of an international panel of scientists “based on their critical review of the published scientific literature.”
U.S.-based Monsanto, which launched the GMO crop boom by genetically engineering field crops to tolerate glyphosate, has vigorously defended the safety of the weedkiller. Assessments by other regulators have said the product poses no risk. For two years, the European Union has been unable to decide whether to extend its license, which expires in mid-December, for use of the chemical. An EU appeal committee may attempt to reach a decision next Monday, said the news site Euractiv.
House Science chairman Lamar Smith has probed for months into the IARC decision. On Nov. 1, he wrote the IARC for information following published reports that it had disregarded studies that indicated glyphosate did not cause cancer and to root out who had rewritten drafts of the proposed IARC finding. Smith and subcommittee chair Andy Biggs said a published report maintained that epidemiologist Aaron Blair “withheld critical research from the IARC” that “could have prevented” the listing of glyphosate as a probable carcinogen.
“It is false to assert Dr. Blair was in a position to withhold critical information from IARC,” said Wild in a written reply, because the material had not been published. The IARC panels review only published research and do not look at “unpublished or ‘secret data’ unavailable publicly.”
In addressing differences between drafts and the final IARC monograph, Wild wrote, “Most of these differences specifically relate to a review article co-authored by a Monsanto scientist and which has been the subject of investigative reporting concerning ‘ghost writing.’ ” The working group decided the material in the article was insufficient to support the conclusions “reached by the Monsanto scientists and other authors.” The IARC said that its evaluations represent “the scientific consensus of the whole working group,” and that there are no individual authors. The monographs are “the preserve of working group members,” whose deliberations are confidential, in order to assure independence, said the IARC chief.
Wild also dismissed the contention by Smith and Biggs that Christian Portier, in a conflict of interest, had steered the IARC into reviewing glyphosate. The congressmen said that “Portier made at least $160,000” as a consultant to law firms that sued Monsanto over glyphosate. Portier worked for the firms at the same time that he chaired an IARC committee that proposed the review of the chemical, they said.
“In April 2014, when Dr. Portier chaired the Advisory Group … he did not have any contractual relationships with litigation lawyers relating to glyphosate nor any other declared activities that could be construed as creating a real or perceived conflict of interest,” wrote Wild. The advisory group had 21 members.
In closing his three-page letter, Wild, who is based in Lyon, France, parried Smith’s broad hint of a congressional investigation of the scientific integrity of the IARC and its cancer assessments. Where Smith asked for names of potential witnesses for a hearing, Wild responded that the IARC “is not in a position to provide witnesses for any potential hearing.” He said the lawmakers were “welcome to visit the agency and pose your questions to me and my staff.”