On January 1, 1997, the U.S. Government, in cooperation with the governments of Canada and Mexico, adopted a new industry classification system, the North American Industry Classification System (NAICS), to replace the Standard Industrial Classification (SIC) codes (April 9, 1997, 62 FR 17288). The applicability of some Part 68 requirements is determined, in part, by SIC codes, and Part 68 also requires the reporting of SIC codes in the RMP. Therefore, EPA has revised Part 68 to replace all references to SIC code'' with NAICS code.'' In addition, EPA is replacing, as proposed, the nine SIC codes with ten NAICS codes, as follows: