Section 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?(a) In General. Sections 176A and 184 of the Act apply for purposes of the 8-hour NAAQS.(b) RACT Requirements for Certain Portions of an Ozone Transport Region.(1) The State shall submit a SIP revision that meets the RACT requirements of section 184 of the Act for each area that is located in an ozone transport region and that is- (i) Designated as attainment or unclassifiable for the 8-hour standard;(ii) Designated nonattainment and classified as marginal for the 8-hour standard; or(iii) Designated nonattainment and covered solely under subpart 1 of part D, title I of the CAA for the 8-hour standard.(2) The State is required to submit the RACT revision no later than September 16, 2006 and shall provide for implementation of RACT as expeditiously as practicable but no later than May 1, 2009. 70 FR 71702 , Nov. 29, 2005