At a high-tension House hearing, members of Congress and expert witnesses yet again debated the safety of the pesticide glyphosate, the active ingredient in Monsanto’s Roundup, the most popular herbicide in the world. The hearing, convened by the House Committee on Science, Space, and Technology, brought a diverse panel to weigh the Environmental Protection Agency’s assessment of the chemical’s safety against the International Agency for Research on Cancer’s assessment.
In 2015, IARC sparked controversy and a cascade of lawsuits when it classified glyphosate as “probably carcinogenic to humans.” The EPA undertook a review of the chemical soon after and in a draft report in December said that it is likely not a carcinogen. EPA’s glyphosate assessment is still underway and will be open to public comment once it is completed.
There have long been fears about Glyphosate’s potential health risks, and traces of the chemical have been detected in consumer products and even in organic foods. But some research and farm groups warn that without glyphosate, U.S. farmers’ abilities to produce certain crops would be hobbled.
IARC, which is the cancer research arm of the World Health Organization, has been criticized by some in the industry for anti-industry bias. One of the hearing witnesses, Dr. Robert Tarone, wrote a critique of IARC’s methods in 2016. His research found that IARC ignored data that disagreed with its conclusion that glyphosate is a probable carcinogen. In the hearing, he said that IARC has never substantively responded to his criticisms. IARC committee members, however, have said that they only consider published scientific studies in their evaluations—and studies cited by industry have not always met that bar.
According to committee leaders, the director of IARC declined to attend the hearing.
Members of the committee expressed strong sentiments both for and against IARC’s methods and designations. Committee vice chair Rep. Frank Lewis, an Oklahoma Republican, said in his opening statement that IARC’s work has “[created] unnecessary fear in people,” and that the glyphosate designation was “agenda-driven manipulation.” Committee Chairman Lamar Smith, a Texas Republican, said in his opening statement that “the selective use of data, and the lack of public disclosure, raise questions about why IARC should receive any government funding in the future.”
But others on the committee disagreed. “For too long, industry’s influence on this process has endangered the public’s health and safety,” said Oregon Democratic Rep. Suzanne Bonamici in support of the IARC’s glyphosate designation. “Today there is an assault on independent scientists, and independent scientific organizations, by the Trump administration, particularly by the Environmental Protection Agency.”
Other panelists represented a range of viewpoints on the issue. Dr. Timothy Pastoor, a toxicologist and former principal scientist for Syngenta, said he believes that IARC’s methods are outdated. Dr. Jennifer Sass, a senior scientist at the Natural Resources Defense Council, expressed support for IARC’s “very credible” research, and emphasized the risks of glyphosate exposure on vulnerable populations. Dr. Anna Lowit, a senior science advisor at EPA, sat somewhere in the middle, and primarily emphasized the agency’s efforts at transparency on this issue.
One difference between the two agencies is the types of assessments they make. IARC makes purely hazard-based assessments, which means that the group may designate a chemical as a carcinogen without qualifying that designation with information about dosage or exposure. The EPA, on the other hand, makes risk-based assessment, in which hazard and exposure are considered together to yield a judgment of whether a chemical is likely to be a health risk.