Companies selling coffee in California will need to post signage to warn of risks.

Los Angeles Superior Court Judge Elihu Berle has ruled that coffee sold in the state of California must carry a cancer warning.

Judge Berle found that Starbucks and other companies failed to prove their case that a chemical found in coffee posed no significant harm, MarketWatch reported.

The Council for Education and Research on Toxics sued coffee sellers back in 2010, alleging that acrylamide, which is a chemical created during the roasting process, is carcinogenic and requires a warning under the California state law known as Proposition 65.

Last fall, the Starbucks and 90 other defendant companies argued for a chance to develop an alternative risk level for acrylamide in coffee.

Berle said in the ruling the companies “did not offer substantial evidence to quantify any minimum amount of acrylamide in coffee that might be necessary to reduce microbial contamination or render coffee palatable.” He also found the defendants arguments that coffee itself has some health benefit “was not persuasive.”

The defendants have a couple weeks to challenge the ruling before it is final and could appeal the ruling, CNBC reported.

According to CNN, if the verdict stands companies such as coffee shops and convenience stores selling coffee in California would need to post warnings about acrylamide with an explanation about the potential risks of drinking coffee, where they are visible at the point of sale.

The cancer agency of the World Health Organization moved coffee off its “possible carcinogen” list in 2016, and studies show coffee is unlikely to cause breast, prostate or pancreatic cancer, and it seems to lower the risks for liver and uterine cancers, according to the agency, CNBC reported. Evidence is inadequate to determine its effect on dozens of other cancer types.