Most people would probably not expect some of the same chemicals found in products like shoe leather and yoga mats to also be in their sandwiches. Food Babe blogger Vani Harirecently reported though, that Subway has been using azodicarbonamide asa dough conditioner in its US products, The Daily Meal reported recently. NBC also recently revealed that other fast food chains like McDonalds, Burger King, Wendy’s and Arby’s use the chemical in their bread products as well. After an online petition started by Hari circulated, Subway has agreed to stop using the chemical in their products, but other fast food chains have been defending their usage of the chemical.

“Food-grade azodicarbonamide is a common ingredient used for whitening and improving the texture of dough,” Burger King representatives said in a statement to The Daily Meal.”It is approved as safe by the Food and Drug Administration (FDA).The substance is found in many restaurant and grocery store baked goods and is used in the baking process of several of our BURGER KING® restaurant bread products. All of our products comply with federal, state and local food safety standards and regulations.”

According to the Center for Science in the Public Interest, the chemical is carcinogenic, and the FDA should consider banning the chemical, CSPI told CNN.

McDonalds, however, has posted on its website a statement that said, "A variation of Azodicarbonamide has commercial uses and is used in the production of some foamed plastics, like exercise mats. But this shouldn't be confused with the food-grade variation of this ingredient."