A Los Angeles judge has ruled that California law requires coffee companies to carry an ominous cancer warning label because of a chemical produced in the roasting process.

Elihu Berle, a superior court judge, wrote in a proposed ruling on Wednesday that Starbucks and other coffee companies failed to show that the threat from a chemical compound produced in the roasting process was insignificant.

A not-for-profit group had sued coffee roasters, distributors and retailers under a state law that requires warnings on a wide range of chemicals that can cause cancer. One of those chemicals is acrylamide, a carcinogen present in coffee.

“While plaintiff offered evidence that consumption of coffee increases the risk of harm to the fetus, to infants, to children and to adults, defendants’ medical and epidemiology experts testified that they had no opinion on causation,” Berle wrote. “Defendants failed to satisfy their burden of proving by a preponderance of evidence that consumption of coffee confers a benefit to human health.”

The coffee industry had claimed the chemical was present at harmless levels and should be exempt from the law because it results naturally from the cooking process necessary to make the beans flavorful.

The case has been developing for eight years and is still not over. A third phase of the trial will determine any civil penalties that coffee companies must pay. With potential penalties of up to $2,500 per person exposed each day over eight years, that figure could be astronomical in a state with close to 40 million residents, though such a large figure is very unlikely.

In the first phase of the trial, Berle said the defense failed to present enough credible evidence to show there was no significant risk posed by acrylamide in coffee.

The law put the burden on the defense to show that the level of the chemical would not result in one excess case of cancer for every 100,000 people exposed. Berle said the epidemiology studies presented were inadequate to evaluate that risk.

Having failed to show there was no significant risk to drinking coffee, the industry had to show during the trial’s second phase that there should be a less strict level for coffee because of health benefits from drinking it. Berle said the coffee companies failed to show that.

The judge can reverse his tentative ruling, but that rarely happens.

