The information in the indirect additive database is generated from an application maintained by the U.S. Food and Drug Administration (FDA) Center for Food Safety and Applied Nutrition (CFSAN) under an ongoing program known as the Priority-based Assessment of Food Additives (PAFA). PAFA contains administrative and chemical information on over 3000 substances mentioned in Title 21 of the U.S. Code of Federal Regulations (21CFR) Parts 175, 176, 177, and 178. These parts of 21CFR deal with what are known as "indirect" food additives. These are substances used in food-contact articles, and include adhesives and components of coatings (Part 175), paper and paperboard components (Part 176), polymers (Part 177), and adjuvants and production aids (Part 178). In general, these are substances that may come into contact with food as part of packaging or processing equipment, but are not intended to be added directly to food. Additional "indirect" additives that are effective as part of the food contact substance notification program or that are exempted from regulation as food additives in accordance with 21 CFR 170.39 Threshold of Regulation exemptions for substances used in food-contact articles are listed in separate inventories.