The United States National Toxicology Program (NTP) has uncovered evidence that exposure to formulated weed killers are potentially more toxic to humans than exposure to their active ingredient in isolation.
Formulated weed killers like Monsanto’s Roundup are widely used by farmers, landscapers, government workers, gardeners, and a host of others. Since it was brought to market in the mid-1970s, the use of Roundup in particular has skyrocketed, netting billions for Monsanto.
The U.S. Environmental Protection Agency (EPA) requested that the NTP conduct testing on formulated weed killers after a 2015 report from the International Agency for Research on Cancer (IARC) concluded that glyphosate, the active ingredient in Roundup, is a probable human carcinogen. The IARC report also expressed concern about the combination of glyphosate and other ingredients that make up formulated weed killer products.
Even though many formulated weed killers use a multitude of other ingredients in addition to glyphosate, government agencies have never examined the toxicity of formulations as used by consumers. Instead, regulators have only conducted extensive testing of glyphosate in isolation.
“This testing is important, because the EPA has only been looking at the active ingredient,” says Jennifer Sass, a scientist with the Natural Resources Defense Council. “But it’s the formulations that people are exposed to on their lawns and gardens, where they play and in their food.”
NTP Conducts First-Ever Examination of Glyphosate Formulations
While the agency’s testing is in the early stages, acting chief of the NTP Laboratory told the Guardian that preliminary findings are clear about one thing: “We see the formulations are much more toxic. The formulations were killing the cells. The glyphosate really didn’t do it,” DeVito said.
According to a summary of the NTP’s work thus far (Effects Of Glyphosate And Its Formulations On Markers Of Oxidative Stress And Cell Viability In HepaRG And HaCaT Cell Lines), glyphosate formulations significantly altered cell viability and mitochondrial membrane potential (MMP).
DeVito cautioned that these initial results do not necessarily mean that glyphosate formulations can cause cancer or other health issues. While the data suggests enhanced toxicity, the NTP summary appears to contradict findings in the IARC report, specifically that glyphosate and/or glyphosate formulations induce oxidative stress, a pathway to cancer. Nevertheless, the NTP will conduct further testing on the potential toxicity of glyphosate formulations on the genetic material of cells to better understand any health risks associated with exposure.
Monsanto and Other Companies Use Trade Secrets to Avoid Disclosing Formulation Ingredients
One of the issues for regulatory agencies studying this issue is that they simply do not know what ingredients are in Roundup or other formulated weed killers. According to documents obtained by Carey Gillam through Freedom of Information Act requests, the EPA is uncertain how the Roundup formulated product has changed over the last three decades. That uncertainty has also affected the NTP’s testing.
“We don’t know what the formulation is. That is confidential business information,” DeVito said. NTP scientists were forced to source samples of Roundup from store shelves. They ended up with products the EPA told them were the top sellers, according to DeVito.
Documents Indicate Monsanto May Not Know the Toxicity of Glyphosate Formulations
According to internal Monsanto communications now known as “The Monsanto Papers”, company scientists may not be clear on the toxicity of the Roundup formulated product. In a 2003 email, Monsanto scientist Donna Farmer said, “You cannot say that Roundup is not a carcinogen … we have not done the necessary testing on the formulation to make that statement. The testing on the formulations are not anywhere near the level of the active ingredient.”
In 2010, another scientist wrote, “With regards to the carcinogenicity of our formulations we don’t have such testing on them directly.”
Yet another email from 2003: “Glyphosate is OK but the formulated product … does the damage.”
Monsanto Faces Thousands of Roundup Cancer Lawsuits in Federal and State Courts
After the IARC report was released in 2015, individuals from across the U.S. filed lawsuits against Monsanto, alleging exposure to Roundup caused them to develop non-Hodgkin lymphoma (NHL). Per IARC, the cancer most commonly associated with exposure to glyphosate is NHL.
The law firm of Baum Hedlund Aristei & Goldman currently represents over 600 individuals who have filed Roundup cancer lawsuits against Monsanto. Some of those cases are pending in a federal multidistrict litigation before U.S. District Judge Vince Chhabria in Northern California. Other state court cases are pending in Missouri and California. The firm also represents individuals in class action litigation against Monsanto over the labeling of Roundup.