This week a local battle over the safety of Roundup will play out in California, as Monsanto and the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) will meet in court. Based on scientific evidence, the state of California was planning to list glyphosate as a carcinogen—and in response, Monsanto sued them.

The clash started in 2015, when the California’s Office of Environmental Health Hazard Assessment (OEHHA) announced it was preparing to list glyphosate – Roundup’s active ingredient – as a substance known to cause cancer. The agency was acting under California’s Safe Drinking Water and Toxic Enforcement Act of 1986, also called Proposition 65. 

OEHHA’s notice came after the International Agency for Research on Cancer (IARC)’s determined that glyphosate is a likely carcinogen. The IARC’s conclusion caused quite a stir in 2015, in part because Roundup was once pitched as benign, and because the weed-killer is so widely used. Nearly 300 million pounds of Roundup are applied to U.S. farms every year, making it the most-used agrichemical in the U.S. 

Monsanto responded swiftly to California’s OEHHA by filing a lawsuit seeking to prevent glyphosate from being added to California’s list of known carcinogens. Monsanto argues that because the IARC is not subject to oversight by a state or federal entity, the OEHHA is violating the company’s right to procedural due process. 

The OEHHA has filed a motion to dismiss Monsanto’s lawsuit in response, pointing out that their reasoning for listing glyphosate as a carcinogen is based not only on the IARC’s determination, but on the basis of several scientific studies. On Friday, January 27, a judge will decide whether or not to allow the case to proceed. After the hearing, environmental lawyer Robert F. Kennedy, Jr. and the law firm of Baum, Hedlund, Aristei & Goldman will hold a press conference. The press conference will take place outside the courthouse at Noon PST. We will be live-tweeting the event and you can follow along here.

While the Environmental Protection Agency is reviewing the safety of glyphosate, states like California and local communities are already acting to protect themselves from Roundup’s harm. 

Larger cities and smaller towns like Portland, Ore. and Dubuque, Iowa have banned or limited Roundup in public places. But based on Monsanto’s objection to California’s efforts to protect its citizens from a likely carcinogen, there will be resistance to local action. Local communities and states should be able to protect their citizens as they see fit based on the scientific evidence available, which strongly suggests that Roundup is harmful to our health.