The EPA approves revisions to the South Dakota State implementation plan (SIP) which update the State's incorporation by reference of the Federal New Source Performance Standards (NSPS). The SIP revisions were submitted by the designee of the Governor of South Dakota on May 2, 1997 and on May 6, 1999. The State adopts the Federal NSPS by reference in subchapter 74:36:07 of the Administrative Rules of South Dakota (ARSD). The State also repealed a rule that required stack tests for asphalt batch plants, aside from the initial stack test required by the NSPS, to be performed if certain conditions existed. EPA approves the revisions to the ARSD 74:36:07 because the revisions are consistent with Federal regulations. This approval action does not extend to sources in Indian country.