Subway recently made headlines when the sandwich chain announced plans to remove a controversial chemical from its bread. Now it seems that may be the tip of the azodicarbonamide iceberg.

Azodicarbonamide is commonly used as a dough "conditioner." It's also used in shoe rubber and yoga mats.

The Environmental Working Group studied the ingredients of thousands of grocery store foods and found nearly 500 foods that contain azodicarbonamide.

The items include many popular brands of breads, hot dog buns, pastries and TV dinners.

The World Health Organization has said that azodicarbonamide is safe for human consumption, but some research suggests it may play a role in the development of skin problems and respiratory issues, including asthma.

The chemical is banned as a food additive in Europe and Australia, but is FDA-approved in the United States in limited quantities.

To see the complete list of products, click here.