The U.S. Supreme Court is expected to rule next month on whether lawsuits can be brought against pesticide and herbicide makers over claims their products have caused cancer.

The court heard arguments in the case in April, and the justices appeared split.

With a ruling weeks away, here are five things to know about the topic of pesticide use and cancer.

1. Geographic correlation between heavy pesticide use and high cancer rates

Numerous studies and an analysis of federal data have shown a potential correlation between pesticide use and cancer.

Out of the 500 U.S. counties with the highest pesticide use per square mile (largely concentrated in corn, soybean and fruit-producing states like Iowa, Illinois, Missouri, California and Florida), 60% have cancer rates higher than the national average of 460 cases per 100,000 people.

A 2024 study in Frontiers in Cancer Control and Society suggests the impact of pesticide use on cancer incidence may rival that of smoking.

2. Thousands of lawsuits have been won against agrichemical companies

State courts have also found that correlation credible, as Bayer, the maker of the herbicide Roundup, has lost thousands of cases and agreed to pay more than $12 billion in settlements, including individual jury verdicts such as an initial $2 billion award in California and a recent $1.25 million verdict in Missouri.

According to the company, more than 65,000 lawsuits have been filed by farmers, gardeners and other users alleging the chemical caused their cancer.