On March 5, 2014, RAP joined the Western Interstate Energy Board (WIEB) for a webinar on forthcoming United States Environmental Protection Agency (EPA) regulations on carbon emissions from existing power plants under Section 111(d) of the Clean Air Act. Listen in as David Farnsworth and John Shenot present an overview of policy options states may have for compliance, with relevant examples from Western states. They emphasize and illustrate the likelihood that compliance decisions made by state air regulators will have cross-state effects, and encourage ongoing dialogues between state air and energy regulators across the West. Vickie Patton of the Environmental Defense Fund and Jack Ihle from Xcel Energy address the legal framework within which EPA must promulgate its Section 111(d) regulations, as well as the effect differing legal interpretations have on compliance options. More than 70 participants from Western state energy offices, public utility commissions, and air quality agencies joined the webinar.