Understanding Subsurface Elevated Temperature (SET) Events is critical for properly operating a municipal solid waste (MSW) facility. Once a SET Event initiates in a MSW landfill, it is difficult to isolate and/or contain the event. Usually, operators take a “wait and see” approach, which delays implementation of techniques to isolate and contain the SET Event. This webinar will present recommendations and suggested best management practices to reduce the impacts of a SET Event and allow the landfill to properly collect landfill gas without initiating and/or expanding the SET Event. This presentation will also discuss proposed changes to the U.S. Environmental Protection Agency (USEPA) New Source Performance Standards (NSPS) and National Emissions Standards for Hazardous Air Pollutants (NESHAP) regulations for landfills under sections 111 and 112, respectively, of the Federal Clean Air Act to reduce the potential for a SET Event to occur. 1.0 PDH