Can chemical in Roundup cause cancer?

California ruling that might lead to warning labels on weed killer is challenged in federal court

Agricultural groups are trying to overturn a California ruling that might require warning labels on a popular weed killer.

According to a recent Associated Press story, a coalition of a dozen national and Midwestern groups is seeking an injunction that would keep the state from enforcing a ban that could include a cautionary phrase about Roundup potentially causing cancer.  

The lawsuit, filed in federal court in Sacramento, claims the warning would be "false" and "misleading" and alleges that the state's decision "violates constitutional due process and free speech rights and should be superseded by federal regulations."

Roundup's main ingredient, glyphosate, has been widely used since 1974. The AP story notes that it kills unwanted weeds while leaving crops and other plants alive — and is not restricted by the U.S. Environmental Protection Agency.

However, the story also reports that International Agency for Research on Cancer, based in Lyon, France, has classified glyphosate as "a probable human carcinogen," an action that prompted the California Office of Environmental Health Hazard Assessment to add it last summer to a list of chemicals known to cause cancer.

That listing, the AP indicates, "could eventually lead to a requirement for warning labels on the product."

Among the plaintiffs is the St. Louis-based Monsanto Co., which makes Roundup and, the suit says, has invested "'hundreds of millions of dollars" in the herbicide and its related glyphosate-tolerant seeds.

Gordon Stoner

Sam Delson

The story quotes Gordon Stoner, past president of the National Association of Wheat Growers, as saying a cancer warning "would result in higher food costs, crushing blows to state and agricultural economies and lost revenue up and down the entire supply chain."

But Sam Delson, COEHHA spokesman, said the agency "is confident its rules are legal."

Details about various disease risks can be found in "Rollercoaster: How a man can survive his partner's breast cancer," a VitalityPress book I, Woody Weingarten, aimed at male caregivers.