The fluorinated chemicals found in the wrappers of sandwiches and burgers known as PFOAs are a family of synthetic compounds. They include chemicals U.S. manufacturers began voluntarily phasing out more than a decade ago because of possible links to kidney and testicular cancer, low birthweight and thyroid disease.

The researchers, whose study was published in Environmental Science & Technology Letters, examined 407 samples from 27 chains. They found fluorinated chemicals in packaging from 21 of the companies, including McDonald’s, KFC and Burger King. The new study is billed as the most comprehensive assessment ever of fluorinated chemicals in U.S. food packaging.

The scientists found fluorinated chemicals in 56 percent of dessert and bread wrappers, in 38 percent of sandwich and burger wrappers, and in 20 percent of paperboard containers. None were found in paper cups.

“The use of fluorinated chemicals in fast food packaging is of great concern since millions of Americans, including children, eat fast food every day,” the study’s lead author, Laurel A. Schaider of Silent Spring Institute, said in a prepared statement.

STAY TUNED: I wrote a whole chapter in Nature's Detox on the effect of these chemicals on our health and on the legacy of our genes- They are raising our RISKS of CANCER and we must KNOW HOW TO DETOX from them. That information coming this SPRING!