The Environmental Protection Agency (EPA) is taking final action to approve a Nevada State Implementation Plan (SIP) revision submitted by the Nevada Department of Environmental Protection (NDEP). On September 27, 2010, the EPA redesignated the Las Vegas Valley area from nonattainment to attainment for the carbon monoxide (CO) national ambient air quality standard (NAAQS) and approved the State's CO maintenance plan ensuring the area would maintain the NAAQS for ten years through 2020. On June 18, 2019, NDEP submitted to the EPA a second 10-year limited maintenance plan for the Las Vegas Valley area that addresses maintenance of the CO NAAQS for a second 10-year period ending December 31, 2030.