Section 52.781 - Rules and regulations(b) A part of the second sentence in section 3, APC-17, which states "Where there is a violation or potential violation of ambient air quality standards, existing emission sources or any existing air pollution control equipment shall comply with th(e) Section 2(d) of APC-20, Fugitive Dust Emissions, is disapproved because it is unenforceable within the terms of the regulation.(f) Subsections 3(b)(3) and 3(b)(5) of APC-2 (May 18, 1977) are disapproved because they are unenforceable within the terms of the regulation.(g)Disapproval. EPA is disapproving 326 IAC 25-2-1, 326 IAC 25-2-3 and 326 IAC 25-2-4 as revisions to the Indiana SIP.(h)Disapproval. EPA is disapproving the December 10, 2009 submittal of 326 IAC 7-4-14 as a revision to the Indiana SIP.37 FR 10863, May 31, 1972, as amended at 37 FR 15084, July 27, 1972; 38 FR 12698, May 14, 1973; 40 FR 50033, Oct. 28, 1975; 43 FR 26722, June 22, 1978; 75 FR 72965, Nov. 29, 2010; 78 FR 78725, Dec. 27, 2013