The Department of Agriculture does not require manufacturers to list flavorings on the label, so anything goes.
In addition, it has been shown that processed meats in general increase the risk of pancreatic cancer by 67% in a study conducted by the University of Hawaii.
Some of the most problematic additives used in hot dogs are nitrates and nitrites. Even organic hot dogs contain nitrites, sometimes even in higher amounts than conventional hot dogs. These two additives combine with amines in processed meat when exposed to high heat, producing nitrosamines. Nitrosamines have been linked to cancer, particularly bladder, pancreatic, colon, and stomach cancer.
The American Institute for Cancer Research indicates that eating one hot dog a day increases the risk of colorectal cancer by 21%.
