SAN ANTONIO (NewsNation Now) — A new study published in Nature reveals that phthalates, a chemical used to keep plastics soft, and similar chemicals were found in food purchased from McDonald’s, Burger King, Domino’s, Pizza Hut, Taco Bell and Chipotle.

The chemicals were also found in gloves used to handle the food, which the study authors hypothesized might be the source of the contamination.

The glove contamination concept would seem to make sense, given that more of the chemicals were found in burritos than hamburgers. Fries, which aren’t usually touched at all, showed no contamination. The study did not come to any firm conclusion on that point, however.

Phthalates are linked to a host of health issues in children and adults. In adults, they have been linked to everything from reproductive issues to endocrine system problems. The National Institutes of Health cited a need to regulate phthalates in food to protect brain development in children, linking the compounds to ADHD and behavioral disorders.

According to The Washington Post, efforts to get a statement from the six chains involved in the sampling were unsuccessful. The FDA has acknowledged being aware of the study findings, but hasn’t yet issued a statement or taken any action.