Is this chemical in decaf coffee unsafe?

Decaffeinated coffee beans are regular coffee beans with the caffeine stimulant removed. There are several methods to decaffeinate coffee, but the most common is called the European method, or the indirect solvent method.

In this method, coffee beans are boiled and then soaked in chemicals like methylene chloride or ethyl acetate, which bind to the caffeine in the coffee beans and extract it. After that, the beans are rinsed to remove any chemical residue, dried, and roasted.

Currently, several environmental and health advocacy groups are calling for FDA to ban methylene chloride in food, arguing that it's harmful to human health. Aside from being used in the decaffeination process, methylene chloride is also used in several industrial processes, including pharmaceutical manufacturing, paint stripping, and metal cleaning.

According to CDC, direct exposure to methylene chloride can lead to drowsiness, dizziness, numbness, and nausea. It has also been associated with eye, skin, liver, and heart damage, and has been designated as a carcinogen by NIH's National Toxicology Program, the Environmental Protection Agency, and the World Health Organization.

In 1985, FDA estimated that the risk of cancer to decaf coffee drinkers was one in a million, but advocates say that this estimate is likely outdated. In FDA's analysis, a cup of coffee was considered just five ounces, which is less than half the size of a "tall" Starbucks drink.

"It should be concerning to everyone that pregnant women and those with health issues looking to cut back on caffeine are unknowingly sipping trace amounts of methylene chloride in their decaf coffee," said Jaclyn Bowen, executive director of the Clean Label Project, an organization that tests consumer products for industrial and environmental contaminants.

Separately, Maria Doa, an official at the Environmental Defense Fund, said that "although the levels of methylene chloride may generally be minimal, it is completely unnecessary because safer processes for decaffeinating coffee are available and being used."

Two chemical-free ways to decaffeinate coffee are the CO2 decaffeination process and the Swiss Water method. The CO2 method involves soaking coffee beans before pumping carbon dioxide into a container to create sparkling water to leach caffeine from the beans. The Swiss Water method involves placing green coffee beans into water and letting the caffeine soak out over several hours.

How the coffee industry has responded

According to William Murray, president and CEO of the National Coffee Association, banning the European decaffeination process, which uses methylene chloride, "would defy science and harm American[s'] health."

"There is no evidence that European Method decaf presents any risk," Murray said. "Indeed, the overwhelming weight of independent scientific evidence shows that drinking European Method decaf, like all coffee, is associated with decreased risk of multiple cancers and with other significant health benefits."

The American Chemical Society has also noted that methylene chloride's "volatility makes it easy to remove residual solvent" from coffee and that any remaining solvent "is well below the 10-ppm concentration allowed by" FDA.

"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 expert who consults with the coffee industry. He also called the effort to ban methylene chloride "ill-conceived."

Coffee industry experts have also said that other decaffeination methods are less effective, more expensive, and result in lower-quality coffee.

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

What you can do if you want to avoid decaf coffee

Currently, more research on how methylene chloride in coffee can affect the human body is needed.

"[T]here still isn't a lot of clear or conclusive research that ingesting residual levels in coffee specifically will cause cancer or other problems," said Monique Richard, a registered dietitian nutritionist and owner of Nutrition-In-Sight.

However, "we certainly want to be obviously proactive and be aware of some of these things," Richard added. "We are exposed to so many things now that anything we can control or ask questions about and decrease that exposure that may be harmful is going to be advantageous."

According to Doa, if you want to avoid exposure to methylene chloride in decaf coffee, look for packages with labels that say solvent-free, Swiss Water processed, or certified organic.

"As a consumer, always do your research," Richard said. "Look up what you can about the company. Ask those questions if you can get on a customer hotline on their website."

And if you're concerned about how much or how often you're drinking decaf coffee, Richard recommends looking for substitutes that are caffeine-free. Some examples include drinks made from chicory root, dandelion root, cacao, rooibos, and yerba maté. (Mallenbaum, Axios, 5/21; Rogers, CNN, 4/17; Florko, STAT+ [subscription required], 3/28; Hoeffner, Food & Wine, 4/16)

Writing for the New York Times, Sophie Egan surveyed some of the top nutrition experts in the country to identify — and debunk — 10 common nutrition myths about fat, plant-based protein, dairy, and more.