NAICS - North American Industry Classification System.
Census Bureau website has bridge tables from this new industry coding system (NAICS) to former code (SIC).
A print edition of the manual, published in 2012, is in the Library, 2d floor Price Gilbert - part of Core collection (call number PREX 2.6/4)
Website from OSHA (Dept. of Labor) which has keyword searching for SIC codes (1987 ed.).
The Standard Industrial Classification Manual was last issued in 1987. Strengths were coding of manufacturing industries. Coding system replaced by NAICS. The 1987 print edition is at the Library Service Center, call number: PREX 2.6/2: IN 27/