(CNN) Glyphosate, an herbicide that remains the world's most ubiquitous weed killer, raises the cancer risk of those exposed to it by 41%, a new analysis says.
Researchers from the University of Washington evaluated existing studies into the chemical -- found in weed killers including Monsanto's popular Roundup -- and concluded that it significantly increases the risk of non-Hodgkin lymphoma (NHL), a cancer of the immune system.
"All of the meta-analyses conducted to date, including our own, consistently report the same key finding: exposure to GBHs (glyphosate-based herbicides) are associated with an increased risk of NHL," the authors wrote in a study published in the journal Mutation Research.
The potential carcinogenic properties of glyphosate are the subject of widespread scientific debate. The US Environmental Protection Agency said in a 2017 draft risk assessment that the herbicide "is not likely to be carcinogenic to humans," while the European Food Safety Authority maintains a similar stance. Bayer, which acquired Monsanto in 2018, said the same year that glyphosate is a "safe and efficient weed control tool."
In 2015, however, the World Health Organization's International Agency for Research on Cancer classified glyphosate as "probably carcinogenic to humans." Moreover, the chemical has triggered multiple lawsuits from people who believe that exposure to the herbicide caused their non-Hodgkin's lymphoma. In 2017, CNN reported that more than 800 people were suing Monsanto; by the following year, that figure was in the thousands.
One high-profile case against Monsanto was that of Dewayne Johnson, a former school groundskeeper diagnosed with terminal non-Hodgkin lymphoma in 2014. In August 2018, a judge ordered Monsanto to pay Johnson $289 million in damages, an award subsequently reduced to approximately $78 million after Monsanto appealed.