The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) announced that effective July 7, glyphosate, the active ingredient in Monsanto’s Roundup weed killer, will be added to the state’s Proposition 65 list of chemicals known to cause cancer.
With the glyphosate Prop 65 listing, California’s Environmental Protection Agency becomes the first regulatory agency in the United States to list the chemical as a known carcinogen.
OEHHA said in its announcement the glyphosate Prop 65 listing will proceed following an unsuccessful attempt by Monsanto to block the agency’s glyphosate listing in court. Monsanto’s requests to stay the listing were denied by a state appellate court and the California Supreme Court.
“OEHHA has made the decision to protect the health of Californians and all those who regard California as a standard bearer,” said attorney Pedram Esfandiary, who was one of dozens to speak about the health risks associated with glyphosate exposure before OEHHA at a public hearing earlier this month.
The process of adding glyphosate to the Prop 65 list began in 2015 when the World Health Organization’s International Agency for Research on Cancer (IARC) classified glyphosate as a “probable human carcinogen.” California legislation permitted OEHHA to adopt IARC’s findings and list glyphosate as a chemical known to the state to cause cancer in accordance with Prop 65.
A ballot initiative approved by voters in 1986 to address concerns about exposure to toxic chemicals, Proposition 65 requires California to publish a list of chemicals known to cause cancer, birth defects or other reproductive harm.
Monsanto filed a lawsuit against OEHHA shortly after the agency announced its intention to list glyphosate as a Prop 65 chemical. On March 10, 2017, Fresno County Superior Court Judge Kristi Kapetan ruled against Monsanto, and just over two weeks later, OEHHA announced on its website that glyphosate would be added to the Prop 65 list.
Monsanto first requested a stay with the Court of Appeals, which was denied on June 15, 2017. On June 16, 2017 Monsanto asked for a stay from the Supreme Court, which was also denied on June 22, 2017. Monsanto filed an administrative petition for reconsideration with OEHHA on June 20, but OEHHA went ahead and listed glyphosate after Monsanto’s stay with the Supreme court was denied.
Listing glyphosate as a chemical known to the state to cause cancer requires companies that sell the chemical to add a warning label to packaging. Monsanto and other companies that sell glyphosate-based herbicides will have one year to comply with the listing.
Warnings would also be required if glyphosate exposure exceeds what is considered safe by regulators. OEHHA is currently debating what should be considered a safe exposure level for glyphosate.
OEHHA proposed a No Significant Risk Level (NSRL) for glyphosate of 1,100 micrograms per kilogram of body weight per day, meaning that any level of glyphosate exposure below the NSRL would not require a warning. A decision on the NSRL is expected within the coming months.
No matter what OEHHA decides with regard to the NSRL, the glyphosate Prop 65 listing will remain in place pending the outcome of Monsanto’s appeal of the OEHHA ruling.