2. You can also search for SIC information at OSHA http://www.osha.gov/pls/imis/sicsearch.html
3. Google (Search company name with NAICS as a keyword)
4. Lexis/Nexis (good for publicly-traded companies and non-profits) Search for the company in the Get Company Info search box at LexisNexis Academic for SIC and NAICS numbers.
6. Reference Book: Standard industrial classification manual HF1041 .U613 (kept at the Reference desk)
The North American Industry Classification System (NAICS) is the standard used by Federal statistical agencies in classifying business establishments for the purpose of collecting, analyzing, and publishing statistical data related to the U.S. business economy.
NAICS was developed under the auspices of the Office of Management and Budget (OMB), and adopted in 1997 to replace the Standard Industrial Classification (SIC) system. It was developed jointly by the U.S. Economic Classification Policy Committee (ECPC), Statistics Canada and Mexico's Instituto Nacional de Estadistica y Geografia to allow for a high level of comparability in business statistics among the North American countries. This link to a non-federal Web site does not imply endorsement of any particular product, company, or content.
The Standard Industrial Classification (abbreviated SIC) is a United States government system for classifying industries by a four-digit code.
Established in 1937, it is being supplanted by the six-digit North American Industry Classification System (NAICS code), released in 1997.