Monsanto Co. and U.S. farm groups sued California on Wednesday to stop the state from requiring cancer warnings on products containing the widely used weed killer glyphosate, which the company sells to farmers to apply to its genetically engineered crops.
California’s government added glyphosate, the main ingredient in Monsanto’s herbicide Roundup, to its list of cancer-causing chemicals in July and will require that products containing glyphosate carry warnings by July 2018.
California acted after the World Health Organization’s International Agency for Research on Cancer (IARC) concluded in 2015 that glyphosate was “probably carcinogenic.”
For more than 40 years, farmers have applied glyphosate to crops, most recently as they have cultivated genetically modified corn and soybeans. Roundup and Monsanto’s glyphosate-resistant seeds would be less attractive to customers if California requires warnings on products containing the chemical.
In the lawsuit, filed in federal court in California, Monsanto and groups representing corn, soy and wheat farmers reject that glyphosate causes cancer. They say the state’s requirement for warnings would force sellers of products containing the chemical to spread false information.