Finding of Failure To Attain by the Attainment Date for the 2010 1-Hour Primary Sulfur Dioxide National Ambient Air Quality Standard; Guam; Piti-Cabras Nonattainment Area

The Environmental Protection Agency (EPA) is determining that the Piti-Cabras, Guam, sulfur dioxide (SO<INF>2</INF>) nonattainment area (NAA) failed to attain the 2010 1-hour SO<INF>2</INF> primary national ambient air quality standard (NAAQS, "standard," or "2010 SO<INF>2</INF> NAAQS") by the applicable statutory attainment date of April 9, 2023. This determination is based on an analysis of available modeling, emissions data, and information concerning control strategy implementation. This action addresses the EPA's obligation under Clean Air Act (CAA) section 179(c) to determine whether the Piti-Cabras SO<INF>2</INF> NAA ("Piti-Cabras area") attained the 2010 SO<INF>2</INF> NAAQS by the April 9, 2023 attainment date.