EPA is approving certain State implementation plan (SIP) revisions submitted by the designee of the Governor of South Dakota on May 2, 1997. The May 2, 1997 submittal included revisions to the Administrative Rules of South Dakota (ARSD) pertaining to the State's regulatory definitions, minor source operating permit regulations, open burning rules, stack testing rules, and new source performance standards (NSPS). This document pertains to the entire State SIP submittal with the exception of the revisions to the NSPS regulations and the new State provision regarding pretesting of new fuels or raw materials: EPA will act on those two regulations separately. EPA has found the remaining rule revisions to be consistent with the Clean Air Act (Act) and corresponding Federal regulations. Therefore, pursuant to section 110 of the Act, EPA is approving the SIP revisions discussed above.