Thirteen companies, including 7-Eleven, agreed on Wednesday to serve coffee with a side of cancer warnings in California. This settlement is in response to a lawsuit first filed in Los Angeles in 2010 by the nonprofit Council for Education and Research on Toxics, arguing that several companies failed to warn their customers that drinking their coffee could expose them to acrylamide.

Acrylamide, a chemical found in coffee and other foodstuffs, including potato chips and bread, has raised concerns because it has been found to increase the risk for cancer in rodent studies. It has yet to be linked to the development of cancer in humans, however. Regardless, the 2010 lawsuit argues that selling coffee without a warning that it can cause cancer is in violation of California’s Proposition 65, which requires businesses give a “clear and reasonable warning” of any agents that can affect health.

On Wednesday, CNN reported that the 13 companies that have conceded to give warning will have to post signs about the potential risk of drinking coffee on store counters and walls.

The remaining nine companies mentioned in the lawsuit, which have not been publicly named but originally included Starbucks and BP West Coast Products, have until February 8 to reach a settlement as well. If they don’t, a judge will likely decide by the end of the year if their practices violate Proposition 65.

7-Eleven, coffee
7-Eleven has agreed to post warnings about coffee.

According to the American Cancer Society, “it’s not yet clear if acrylamide affects cancer risk in people.” While it has been found to increase the chance of developing several types of cancers in rats and mice when inserting into their drinking water, it has not been found to increase the risk of cancer for humans. Because of the animal model results, the International Agency for Research on Cancer identifies acrylamide as a “probable human carcinogen” and the U.S. Environmental Protection Agency classifies it as “likely to be carcinogenic to humans.”

Whether or not coffee contains enough acrylamide to cause damage is debatable. It forms in coffee as an consequence of roasting the beans. The Council for Education and Research on Toxics (CERT) asserts that its goal isn’t to get rid of coffee altogether but to get companies to change the roasting process.

“I’m addicted — like two-thirds of the population,” CERT’s lawyer Raphael Metzger told the Associated Press in September. “I would like the industry to get acrylamide out of the coffee so my addiction doesn’t force me to ingest it.”

lawsuit, coffee
A section of the lawsuit.

In response to the lawsuit, Bill Murray, CEO of the National Coffee Institute, released a statement to CNN saying, “Coffee has been shown over and over again, to be a healthy beverage. The U.S. Government’s own Dietary Guidelines state that coffee can be part of a healthy lifestyle. This lawsuit simply confuses consumers, and has the potential to make a mockery of Prop 65 cancer warning at a time when the public needs clear and accurate information about health.”

Many studies have found that coffee is healthy in some ways: It can decrease the chance of developing liver cirrhosis after drinking too much alcohol, drinking it in moderate amounts can decrease the chance of developing Alzheimer’s and dementia, and it appears to reduce the likelihood of dying from digestive or circulatory diseases. In order to definitively say whether it can cause cancer in humans, however, more studies must take place.