Take a look at ingredients for some varieties of Subway's bread and you'll find a chemical that may seem unfamiliar and hard to pronounce: azodicarbonamide.
To say this word, you would emphasize the syllable "bon" - but the attention the chemical has been getting has not been good. Besides bread, the chemical is also found in yoga mats and shoe soles to add elasticity.
"We are already in the process of removing azodicarbonamide as part of our bread improvement efforts despite the fact that it is (a) USDA and FDA approved ingredient," Subway said in a statement. "The complete conversion to have this product out of the bread will be done soon."
One of the breakdown products, derived from the original substance, is called urethane, a recognized carcinogen, the organization says. Using azodicarbonamide at maximum allowable levels results in higher levels of urethane in bread "that pose a small risk to humans," CSPI said.
Another breakdown product is semicarbazide, which poses "a negligible risk to humans" but was found to cause cancers of the lung and blood vessels in mice, CSPI said.
CSPI advocates for reducing the amount of the chemical that is allowed to be used.
"We urge the Food and Drug Administration to consider whether the Delaney amendment, which bars the use of food additives that cause cancer in humans or animals, requires the agency to bar its use," CSPI said.