WASHINGTON, D.C. — The U.S. Supreme Court is scheduled to hear oral arguments on April 27 in a case brought by Monsanto that will determine whether federal pesticide law pre-empts states' labeling requirements for products containing glyphosate, a widely used weed-killing chemical that has been linked to cancer in multiple studies. The case could reshape the legal landscape for thousands of pending lawsuits filed by people who say glyphosate-based herbicides caused them to develop cancer.

Monsanto argues that under the Federal Insecticide, Fungicide, and Rodenticide Act, known as FIFRA, it cannot be held liable for failing to warn of a cancer risk if the Environmental Protection Agency has not determined that such a risk exists. Monsanto states in its Supreme Court brief: "EPA has determined that glyphosate and Roundup do not cause cancer and that a warning stating otherwise is neither required nor permitted under Fifra." A ruling in its favor, the company has said, would help end lawsuits by people who claim Roundup and other glyphosate products caused their cancer.

After losing multiple jury trials, Monsanto, which has been owned by the German conglomerate Bayer since 2018, has paid billions of dollars to resolve the bulk of glyphosate lawsuits and has proposed spending $7.25 billion toward a class action settlement aimed at resolving up to 60,000 pending cases. Opposing legal briefs warn that if the Court sides with Monsanto, consumers could lose the right to sue if they develop cancer or other serious diseases they believe are caused by exposure to dangerous chemicals.

Hundreds of organizations and individuals have filed legal briefs on both sides. More than 100 groups filed briefs opposing Monsanto's position, arguing that federal law allows separate state labeling requirements and that a new interpretation of FIFRA's pre-emption provisions would immunize manufacturers from accountability. Eight former EPA officials, a group of scientists, more than a dozen farmworker groups, and U.S. Senator Cory Booker filed briefs against Monsanto.

A federal court vacated the EPA's most recent glyphosate safety review, finding the agency's assessment was not scientifically sound. Attorneys general for Texas, Florida and Ohio cited a 2005 Supreme Court case in briefs urging the court not to rule for Monsanto. "Pre-emption through federal agency action poses particular threats to state sovereignty," the attorneys general wrote.

On the other side, more than 100 groups filed briefs supporting Monsanto, including attorneys general for 15 states and dozens of agricultural organizations. Several farm groups argue that removing glyphosate from the market would pose an immediate risk to the country's food supply. The U.S. Solicitor General filed an amicus brief supporting Monsanto, and a February executive order directed that glyphosate production be protected.

"The political pressure should play no role in the Court's decision," said Nora Freeman Engstrom, a professor at Stanford Law School. "In some areas, the views of the federal government are entitled to special deference. This isn't one of those areas," she added.

Members of the Make America Healthy Again movement are planning a rally outside the Supreme Court building ahead of the hearing. Many organizations and individuals have also entered a court lottery for tickets to attend the April 27 arguments in person.