Does decaf coffee contain a harmful additive? Advocates want to ban a certain chemical in the brew

WASHINGTON — There’s a fight brewing over the future of decaf coffee.

Consumer health advocates are petitioning the Food and Drug Administration to ban a key chemical, methylene chloride, used to decaffeinate coffee beans. While the chemical is almost entirely removed during the decaffeination process, advocates say that a little-known nearly 66-year-old federal law mandates the agency ban the additive because it has been proven to cause cancer in rodents.

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Methylene chloride, a since-banned consumer paint stripper, is used by nearly all of the major coffee companies in the U.S., including Starbucks and Dunkin’ Donuts, according to data compiled by the advocacy group Clean Label Project. The ingredient acts as a solvent, binding to caffeine in coffee beans so it can then be discarded.

Advocates know what they’re doing. In 2018 they successfully used the same argument to force a ban of seven artificial flavors used in foods.

The move is the latest flashpoint in a decades-long fight over the FDA’s regulation of food additives, which has been reignited in recent years largely thanks to renewed efforts by activists who have cobbled together a creative legal strategy to force federal bans of potentially cancerous food additives.

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The effort to ban methylene chloride centers on a provision in the FDA’s food additive laws, known as the Delaney Clause, which states that “no additive shall be deemed to be safe if it is found to induce cancer when ingested by man or animal.”

What the Delaney Clause means in practice is that the FDA can be forced to ban a substance that only has been proven to cause cancer in animal studies that don’t mimic anything close to the conditions consumers would face when consuming a product. The provision has been a source of constant frustration for the food industry — and even some FDA officials — since its passage in 1958.

“Every FDA chief counsel … has had to try to make sense out of it, because, of course, it doesn’t make any sense,” said Peter Barton Hutt, who served as FDA chief counsel from 1971 to 1975 and later represented the industry in food additive litigation.

The provision has forced the FDA to ban substances that regulators insist are safe. In 2018, for example, the FDA banned several artificial flavorings linked to cancer in rodents, despite the fact that the agency had “reasonable certainty that the substances do no harm under the intended conditions of use.” The coffee industry and its advocates say a similar situation is playing out with methylene chloride. The chemical is virtually undetectable in a brewed cup of decaf coffee, which is roasted at high temperatures after being decaffeinated.

“There’s more methylene chloride in the water that you brew your decaf with than came with the decaf roasted beans,” said James Coughlin, a food toxicology consultant to the coffee industry, who called the effort to ban the chemical “just so ill-conceived.”

In fact, the coffee industry argues banning the substance would actually harm consumers’ overall health and “deprive U.S. consumers of multiple documented health benefits associated with drinking decaffeinated coffee, including increased longevity and decreased risk of multiple cancers.”

The cancer risk linked to drinking decaf coffee is likely very low. The FDA estimated in 1985 that the risk of cancer for decaf drinkers was one in a million — though advocates maintain that that estimate is likely outdated. They note, for example, that the FDA considered a cup of coffee in that analysis to be just 5 ounces, which is less than half of a “tall” Starbucks cup, and just one-quarter the size of a “venti.”

They argue too that decaffeination of coffee puts those working in coffee factories at unnecessary risk, even if the ultimate consumer is likely pretty safe. The Environmental Protection Agency banned the use of methylene chloride as a consumer paint stripper in 2019 after finding that its use in “paint and coating removal present an unreasonable risk to human health.”

Most of all, advocates say there’s no reason not to ban the chemical given there’s other, albeit more expensive, ways to decaffeinate coffee.

“It’s not as if there’s no good substitute,” said Maria Doa, an official at the Environmental Defense Fund that is petitioning for the ban.

The coffee industry has argued, however, that the other methods for decaffeinating coffee — which typically involve extracting caffeine from coffee beans using water — are less effective, are more expensive, and lead to lower-quality coffee.

“Methylene chloride has always been the solvent of choice to remove caffeine from green coffee,” wrote a global coalition of decaf coffee companies in a recent letter to the FDA. “True coffee aficionados, in blind tasting, select the methylene chloride decaffeinated coffee as one of the best in class.”

It’s not the first time there’s been a push to ban the ingredient. In 1987 the advocacy group Public Citizen sued the FDA in an attempt to force a ban. The effort was thwarted when a judge ruled that the FDA was still considering the legality of the chemical and therefore couldn’t be sued at that time.

In the decades since that ruling, methylene chloride has remained the most popular way to decaffeinate coffee.

“I haven’t thought much about methylene chloride since,” said Coughlin, the toxicologist for the coffee industry, who said he thought this was an issue “we handled 40 years ago.”

The reignited efforts are the latest sign of a renewed push among food safety advocates to force a crackdown on potentially cancerous food additives. Much of that work can be traced back to the Environmental Defense Fund, which has commandeered the petitions the food industry typically uses to ask for regulators’ permission to introduce a new additive into the food supply, to instead force a ban on an existing product.

Dr. Maricel Maffini “and I started the strategy in 2014,” said Tom Neltner, the longtime head of the EDF’s chemical safety work, who recently left the organization to run a group focused exclusively on efforts to reduce children’s exposure to lead. “We’ve probably got 10 [or] 12 of those petitions in.”

It’s unclear what food additive could be challenged next, though advocates have complained about several substances, ranging from the artificial sweeteners aspartame and saccharin to the preservatives BHA and TBHQ, all of which have been shown to cause cancer in animals, and all of which are still on the market.