The Environmental Protection Agency (EPA) is taking final action on portions of six submissions from the state of Wyoming that are intended to demonstrate that the State Implementation Plan (SIP) meets certain interstate transport requirements of the Clean Air Act (Act or CAA). These submissions address the 2006 and 2012 fine particulate matter (PM<INF>2.5</INF>) National Ambient Air Quality Standards (NAAQS), 2008 ozone NAAQS, 2008 lead (Pb) NAAQS, 2010 sulfur dioxide (SO<INF>2</INF>) NAAQS and 2010 nitrogen dioxide (NO<INF>2</INF>) NAAQS. The interstate transport requirements under the CAA consist of four elements (or prongs): Significant contribution to nonattainment (prong 1) and interference with maintenance (prong 2) of the NAAQS in other states; and interference with measures required to be included in the plan for other states to prevent significant deterioration of air quality (prong 3) or to protect visibility (prong 4). Specifically, the EPA is approving Wyoming's submissions for interstate transport prongs 1 and 2 for the 2008 Pb and 2010 NO<INF>2</INF> NAAQS, and approving prong 1 and disapproving prong 2 for the 2008 ozone NAAQS. The EPA is also approving interstate transport prong 4 for the 2008 Pb and 2010 SO<INF>2</INF> NAAQS, and disapproving prong 4 for the 2006 PM<INF>2.5</INF>, 2008 ozone, 2010 NO<INF>2</INF> and 2012 PM<INF>2.5</INF> NAAQS.