A study from the University of Notre Dame found that fast food restaurants are still using the grease-resistant wrappers treated with the same chemicals used in floor wax, even though the chemicals are known to be harmful.
The chemicals, known as per- and polyfluoroalkyl substances, or PFASs, have been previously linked to kidney and testicular cancer, thyroid disease, low birth weight and low sperm count, according to New Atlas. Although the compounds are only used in the fast food wrappers, other studies have confirmed that these fluorinated substances can leach into the food itself, especially when it's hot and greasy.
Perfluorooctanoic acid, known as PFOA, a similar fluorinated chemical, was phased out of food packaging in 2015.
The Verge reports that one-third of the fast food wrappers tested contained the harmful chemicals. More than 400 types of packaging from 27 fast food chains were tested, including those from Starbucks, McDonald's, Taco Bell and Dunkin' Donuts.
Philippe Grandjean, a professor of environmental health at Harvard, who was not involved in the study, tells the Verge that PFASs can especially affect children, whose bodies are still growing and are more vulnerable to toxins. The chemicals are thought to interfere with vaccine effectiveness, preventing normal immune responses to vaccinations.
According to New Atlas, one-third of children eat fast food daily. The researchers contacted the fast food restaurants involved in the study and informed them of their findings. Only two responded and both said they believed their packaging was PFAS-free.
"While it is difficult to draw conclusions on the basis of so few responses, this suggests a lack of knowledge in the fast food industry about the use of fluorinated packaging," the researchers wrote in the study published in Environmental Science & Technology Letters.
Arlene Blum, director of the Green Science Policy Institute and one of the researchers who contributed to the study, advocates for completely replacing PFASs with another, safer chemical.
“The question is, do you really need it, given the potential for harm?” asks Blum, according to The Verge. “Maybe you’d rather have greasy fingers than eat fluorinated chemicals with your french fries.”