- FDA - Color Additives Fact Sheet - What the FDA says about artificial colorings.
- FDA Listing of Color Additives, details of requirements for certification - amounts of contaminants allowed
- FD&C Yellow #5, Code of Federal Regulations - note how much benzidine is allowed, as well as how much lead, mercury, and arsenic.
- FDA Summary of Color Additives Listed for Use in the United States in Foods, Drugs, Cosmetics, and Medical Devices, November 2000
- How much do we use? - FDA - Color Certification Reports
- National Toxicoloty Program Report on Carcinogens