Agricultural groups challenge California weed-killer warning

SAN FRANCISCO – A coalition of national and Midwestern agricultural groups is suing to overturn a California declaration that the popular weed-killer Roundup can cause cancer.

The federal lawsuit filed Wednesday in California seeks an injunction barring the state from enforcing what the suit describes as a “false” warning that could eventually appear on product labels for the herbicide.

It claims the warning violates constitutional due-process and free-speech rights, as well as the supremacy clause giving precedence to federal regulations over state ones.

Roundup’s main ingredient, glyphosate, is not restricted by the U.S. Environmental Protection Agency.

But the International Agency for Research on Cancer, based in France, has classified it as “a probable human carcinogen.” That led California to decide to add it to its list of chemicals known to cause cancer.