Is decaf coffee safe to drink? Experts weigh in on claims by health advocacy groups

For people avoiding caffeine, decaf coffee seems like a harmless option. But some health advocacy groups that argue otherwise are petitioning the U.S. Food and Drug Administration to ban a key chemical involved in the decaffeination process due to cancer concerns.

For people avoiding caffeine, decaf coffee seems like a harmless option. But some health advocacy groups that argue otherwise are petitioning the U.S. Food and Drug Administration to ban a key chemical involved in the decaffeination process due to cancer concerns.

That chemical is methylene chloride, a colourless liquid that’s used in certain industrial processes, “including paint stripping, pharmaceutical manufacturing, paint remover manufacturing, and metal cleaning and degreasing,” according to the Occupational Safety and Health Administration.

Methylene chloride has long been known to be a carcinogen, designated as such by the National Institutes of Health’s National Toxicology Program, the Environmental Protection Agency and the World Health Organization, said Dr. Maria Doa, senior director of chemical policy for the Environmental Defense Fund, one of five groups and individuals behind two food and color additive petitions sent to the FDA in November.

The FDA filed the petitions to its docket for consideration on December 21 and accepted public comments on the filing notice through March 11.

“In addition to being carcinogenic, methylene chloride can cause other health harms, such as liver toxicity and at higher exposures neurological effects, and in some cases death,” Doa added via email. These risks are in the context of external acute exposure to high levels of the chemical, or ingestion of the chemical on its own, according to the U.S. Centers for Disease Control and Prevention.

The toxicity of the chemical led the EPA to ban its sale as a paint stripper in 2019; in 2023 the agency proposed a ban of its sale for other consumer uses and many industrial and commercial uses, Doa said. But food uses regulated by the FDA under the Federal Food, Drug and Cosmetic Act remain. (The state assembly in California — which has one of the largest economies in the world, often influencing the rest of the nation — recently introduced a bill seeking to ban using methylene chloride in the decaffeination process.)

The Environmental Defense Fund and its co-petitioners argue that by allowing methylene chloride in food, the FDA “has been disregarding” a 66-year-old addition to the federal act called the Delaney Clause, which requires the FDA to ban food additives proven to cause or induce cancer when ingested by humans or animals.