The EPA approves revisions to the South Dakota State implementation plan (SIP) submitted on May 2, 1997 and May 6, 1999 regarding the testing of new fuels or raw materials. Specifically, the State adopted a new provision in Chapter 74:36:11, Performance Testing, of the Administrative Rules of South Dakota (ARSD) that allows permitted sources to request permission to test a new fuel or raw material, to determine if it is compatible with existing equipment and to determine air emission rates, before requesting a permit amendment or modification. The State will grant approval for such testing of a new fuel or raw material if certain conditions in the State's regulation are met. The State's regulation provides, among other things, that the State will not approve a test if the test would cause or contribute to a violation of a national ambient air quality standard (NAAQS). EPA approves these revisions regarding testing of new fuels or raw materials because the revisions are consistent with the requirements of the Clean Air Act (Act) and applicable Federal regulations.