Effective on Friday, California will add a weed killer made by Monsanto to its list of chemicals "known to the state to cause cancer."
Glyphosate, a chemical found in the widely used herbicide Roundup, now officially joins hundreds of other chemicals determined by the state to be linked with cancer. Monsanto disputes the designation, and is pursuing an appeal in a court case over the issue.
California's decision is at odds with conclusions reached by other government agencies, including the federal EPA and European agencies, which have said that scientific evidence does not support linking glyphosate with cancer. However, the state's listing is in keeping with the World Health Organization's conclusion that glyphosate is "probably" cancer-causing to humans.
California's decision will not result in a state-wide ban, but products containing glyphosate will be required to carry a warning label.
Some local governments, including the city of Encinitas, have already implemented municipal bans on glyphosate.
Glyphosate is no longer sprayed in Encinitas parks or on the city's public lands, due to a 2015 city council decision. Encinitas park operations manager Annette Saul said the city has found ways to suppress weeds without relying on glyphosate.
"There are other herbicides we're able to use, and we also use manual labor," she said. "People wanted it not to be used in the city, and the council's direction was to ban it."
Saul said the city has not determined how fazing out glyphosate has affected the city's landscaping costs.
Elsewhere in California, Irvine's city council has also decided to move away from using glyphosate, and the Burbank Unified School District no longer sprays the weed killer on school grounds.
