Roundup manufacturer Monsanto is suing the state of California for placing cancer warnings on products containing glyphosate.
California labeled Glyphosate, a key ingredient in Roundup, a carcinogen in July. Roundup could be required to display a cancer warning by July 2018 in accordance with the state's Proposition 65.
Monsanto has contested that its product could cause cancer ever since the World Health Organization’s International Agency for Research on Cancer listed it as "probably carcinogenic" in 2015.
Other studies have found no link between the chemical and cancer. In 2007, the Office of Environmental Health Hazard Assessment determined it was not a likely carcinogen.
Earlier in November, a study of U.S. farm workers published as part of a project called Agricultural Health Study found no connection between glyphosate and cancer.
A scientist who sat on the 2015 IARC panel regarding glyphosate said in June he was aware of the AHS research at the time, but didn't mention it because it had not yet been published, according to Reuters.
Regardless of the health consequences or lack thereof, California's warning would hurt Monsanto, which sells the weed-killer to farmers who grow the company's genetically modified corn, wheat and soy.
Farmers would also be hit by the regulation, which would increase costs through required tests and scare away consumers.
Representatives from agricultural industries including the Iowa Soybean Association, the Agribusiness Association of Iowa and the National Corn Growers Association have joined Monsanto in suing California. Organizations from Missouri and the Dakotas are also part of the lawsuit, the Des Moines Register reports.
Kirk Leeds, CEO of the Iowa Soybean Association, said the effect of requiring a cancer warning label in the nation's most populous state would be "a devastating blow to Iowa soybean farmers and an industry valued at more than $5 billion.'
Leeds also criticized the assessment of the herbicide's safety, saying that numerous studies have proven that it is "one of the safest herbicides ever developed."
“Everything that we grow is probably going to have to be labeled,” said Blake Hurst, president of the Missouri Farm Bureau, a plaintiff in the lawsuit.
Under one proposal, products containing low amounts of glyphosate might not have to be labeled. Those products are considered as having No Significant Risk Level, according to state spokesman Sam Delson.
"We do not anticipate that food products would cause exposures that exceed the proposed NSRL," he said. "However, we cannot say that with certainty at this point and businesses make the determination."