For two of the three substances Zota examined—phthalates designated as DEHP and DiNP—there was a significant relationship between fast-food intake and exposure. People who ate more fast food had more evidence of phthalates in their urine. The third chemical they measured was Bisphenol A, or BPA, which is commonly used to line aluminum cans. That wasn’t significantly correlated with fast-food intake.

It’s difficult to determine what the health risks of phthalates are. The American Chemistry Council says that they’ve been thoroughly studied and “phthalates used in commercial products do not pose a risk to human health at typical exposure levels.” The Environmental Protection Agency, in a 2012 Phthalates Action Plan, notes that it is “concerned about phthalates because of their toxicity and the evidence of pervasive human and environmental exposure to them.”

Japan banned vinyl gloves in food preparation over concerns about DEHP, and the European Union has limited the use of the chemicals in food products and toys. Some phthalates, including DEHP, were restricted in children’s toys in the U.S. by a 2008 law.