Coffee can give you the boost you need to make it through the day. And some studies have reported that drinking coffee can actually be good for you. But a new rule in California could make you think twice about guzzling your morning cup of joe. Soon, coffee sellers in the Golden State could be required to display a cancer warning in their stores.

Coffee hasn’t become more toxic all of a sudden. Rather, the new change has to do with Proposition 65. This measure from the Environmental Protection Agency requires California businesses to alert customers when they are exposed to potentially cancer-causing chemicals. One of these chemicals, acrylamide, is a natural byproduct of cooking certain foods at high temperatures — including coffee beans. In 2010, the nonprofit Council for Education and Research on Toxics filed a lawsuit in the state of California stating that coffee drinkers could be exposed to acrylamide, and that, therefore, companies that served coffee needed to warn their customers.

So far, 13 companies have agreed to post warning labels on walls or store counters, including 7-Eleven. Nine other defendants will face a trial on February 8th, and if the judge rules that they have violated California law, they will have to post cancer warnings and potentially pay a fine. The defendants have argued that the small level of acrylamide in coffee poses no risk to consumers.

So, does coffee actually cause cancer?

It’s notoriously difficult to determine the effects of a single food product on the human body. But according to the American Cancer Society, studies have found that acrylamide caused cancer in rats — but only when the animals were exposed to 1,000 to 10,000 times as much acrylamide as the average human. You may drink a lot of coffee, but chances are you consume a lot less acrylamide than those rats. As for human studies, results have been inconclusive.

The bottom line is that we don’t really know if drinking coffee causes cancer. And aside from the fact that excessive caffeine can be bad for you, you don’t need to worry about your coffee consumption too much. Until we find out for sure that coffee is bad for us, we’re going to keep enjoying our morning cup (or two).