Industry Classification

Foreign Trade Classification Codes
http://www.census.gov/foreign-trade/reference/codes/index.html
Publisher: U.S. Bureau of the Census

Harmonized Tariff Schedule of the United States
http://www.usitc.gov/tata/index.htm
Publisher: U.S. International Trade Commission. Office of Tariff Affairs and Trade Agreements.
Catalog Record/Annotation 98644901

North American Industry Classification System (NAICS)
http://www.census.gov/epcd/www/naics.html
Publisher: U.S. Bureau of the Census
Catalog Record/Annotation 98803224

PLU Codes (for produce)
http://plucodes.com/
Publisher: International Federation for Produce Standards