Display shelf containing coffee products available for purchase at a Starbuck's Cafe in South Pasadena, CA. Photo: Philip Pilosian

A long-running lawsuit that seeks to add a cancer warning to coffee based on a natural chemical in the beverage continues to wind its way toward a conclusion in California courts.

The lawsuit was originally filed by the Council for Education and Research on Toxics in 2010, according to the Metzger Law Group, which represents the non-profit.

The court documents available online argue that Starbucks and other coffee purveyors did not appropriately list acrylamide in warnings based on Proposition 65, otherwise known as the California Safe Drinking Water and Toxic Enforcement Act of 1986.

Thirteen of the defendants have already agreed to add the warning, and a mediation with the coffee retailers is set for next week, according to the latest reports.

Acrylamide, which is released when coffee beans are roasted, was first identified as a carcinogen for humans in 2002 based on animal research performed by the International Agency for Research on Cancer. However, further research published in 2014 contended that the studies showing the elevated cancer risks were done with doses from 1,000 to 100,000 times higher than relative amounts ingested by humans.

Other agencies have argued over the effects – or benefits – of coffee in incremental studies. Some show coffee can stave off cirrhosis, while others tout protective properties that prevent prostate cancer.

In California, however, it is already labeled in some stores and restaurants as a cancer-causer.

The suggested warning statement in a 2012 consent judgment with companies including Gloria Jean’s Gourmet Coffees, It’s a Grind, and Praise stores covers a wide swath of products.

“WARNING,” it reads, in part. “Chemicals known to the State of California to cause cancer and reproductive toxicity, including acrylamide, are present in coffee, baked goods, and other food or beverages sold here. Acrylamide is not added to our products, but results from cooking, such as when coffee beans are roasted or baked goods are baked. As a result, acrylamide is present in our brewed coffee, including coffee made at home or elsewhere from our beans, ground or instant coffee, baked good or other foods sold here, in grocery stores or other retail locations.”

The warning had to be in a visible location, on a sign at least 10 inches square, according to the filing.

The National Coffee Association, an industry group, has maintained throughout the litigation that coffee brings health benefits, not risks.

“Overwhelming research shows that regular coffee consumption is linked to a host of potential health benefits, from liver health to longevity,” the group says on its website. “Together, the chemicals in coffee work together to create a delicious beverage that can be part of a healthy lifestyle.” 

Acrylamide has been questioned through “aggressive” legislation and litigation – but the chemical remains a non-risk, the group added.

“While we encourage consumers to do their research and make good choices, the amount of acrylamide in coffee is negligible and does not present a risk - even when consumed in larger or more frequent quantities,” they add.

The Metzger lawyers have previously filed Proposition 65 cases against fast food and other groups. In 2008, McDonald’s and Burger King agreed to provide warnings about acrylamide in their French fries, and agreed to pay civil penalties and attorney’s fees.

The latest Prop 65 list includes nearly 1,000 substances – including wood, dust and talc, among many others.