Only two out of a group of 11 industry studies given to European regulators in support of the re-approval of the main ingredient in Roundup herbicide are scientifically “reliable”, according to a new analysis of corporate-backed studies on the chemical glyphosate.
Glyphosate is the world’s most widely used herbicide and is not only the main ingredient in Roundup herbicide but also in hundreds of other products. It is extensively used by farmers in growing common food crops.
In a report released on Friday, researchers from the Institute of Cancer Research at the Medical University of Vienna in Austria said their review of a set of safety studies submitted to EU regulators by Bayer AG and a coalition of other chemical companies showed that the vast majority do not meet current international standards for scientific validity.
While two of the corporate studies were considered reliable, six were considered partly reliable and three were not reliable, according to the report.
The “reliable” studies were from 2016 and 2020 and both were sponsored by Monsanto, the original patent holder on glyphosate and maker of Roundup. Those considered not reliable were done more than a decade ago: two were sponsored by the former DuPont Co and one by the plant biotechnology firm Verdia Inc.
The corporate studies analyzed in the report concern the genotoxic properties of glyphosate. The companies maintain that glyphosate is not genotoxic, meaning it doesn’t cause DNA damage, which is a well-recognized factor in cancer development.
But Siegfried Knasmueller, the lead author of the report, told the Guardian that not only are most of the studies lacking in quality, but that the industry research does not include new and “probably better tests for the detection of genotoxic carcinogens”. He said there is evidence in published research that glyphosate may cause DNA damage in human-derived liver cells.
He said that while several industry studies were “correct from a methodological point of view at the time when they were conducted”, they are “not in agreement with the current strategy”.
In July, Knasmueller authored a similar report looking at 53 glyphosate studies submitted to regulators.
The new report alleging flaws with the corporate glyphosate studies comes at a critical time as the European Chemicals Agency (ECHA) and the European Food Safety Authority (EFSA) are evaluating whether or not to renew the license for glyphosate in the EU when current approval expires 15 December 2022.
In August, authorities from France, Hungary, the Netherlands and Sweden weighed in on the renewal question with a draft report concluding that glyphosate is not carcinogenic.
ECHA and EFSA allowed other “interested parties” to consult on the renewal question until 22 November. The Knasmueller analysis, which was requested by the SumOfUs non-profit advocacy group, was submitted as part of that consultation.
An ECHA spokesperson declined to comment on the Knasmueller report. The agency said it would “develop its opinion” on the glyphosate classification by June. An EFSA spokesperson said the Knasmueller report would be considered alongside all other comments submitted as part of the consultation.
Bayer, the lead registrant for the European renewal request, also did not offer a comment on the report.
Two independent scientists asked about Knasmuller’s report said it is not surprising that studies done years ago may not meet current guidelines, but that would be true of independent studies as well as corporate studies. They also said such studies should not necessarily be ignored.
For the last few years there has been a heated global debate about whether or not glyphosate herbicides such as Roundup should be restricted or banned because some scientific research shows that exposure to the weedkiller causes health problems.
In 2015 the World Health Organization’s International Agency for Research on Cancer pointed to several independent research studies in concluding that there was strong evidence of genotoxicity with the weedkiller, and glyphosate should be considered a probable human carcinogen.
Bayer, which bought Roundup maker Monsanto in 2018, denies there is any valid evidence the herbicides cause cancer. But the company has agreed to pay about $14bn to settle US litigation brought by more than 100,000 Roundup users alleging exposure to the weedkiller caused them to develop non-Hodgkin lymphoma. Bayer has also agreed to stop selling glyphosate to US consumers by 2023.
The report by Knasmueller and colleague Armen Nersesyan underscores growing concerns about a history of regulatory reliance on corporations to provide safety studies on the chemicals they are making and selling. A new system should be developed to eliminate corporate bias that could influence results, many scientists say.
“The government shouldn’t rely on industry studies,” said Peter Infante, former senior epidemiologist and director of the US office of carcinogen identification and classification for the Occupational Safety and Health Administration. “If the industry wants to do studies they should put the money into a pool and distribute it to independent scientists that don’t have conflicts of interest. That is the way it should be.”