The California Department of Toxic Substances Control (DTSC), pursuant to authority granted under Division 4.5, California Code of Regulations, Title 22, Chapter 20 prepared an addendum to amend the existing Hazardous Waste Facility (HWF) Permit to include additional project activities at the Edwards Air Force Base Hazardous Waste Facility (Facility). DTSC received a Permit Modification application for the Facility as authorized by the California Health and Safety Code, Chapter 6.5. The Facility is located at 195 E Popson Ave, Building 2750, Edwards Air Force Base, CA 93254 and operates under a current Hazardous Waste Facility Permit. Facility is a military base operated by the U.S. Air Force. It is home of the Air Force Flight Test Center and is responsible for US Air Force Research, Development, Test and Evaluation (RDT&E) of new and modified aircraft weapon systems and sub-systems. The RDT&E operations include testing various types of munitions dropped from aircraft and firing small and large caliber weapons. The Air Force Research Laboratory is also located at EAFB and is responsible for RDT&E of liquid and solid rocket motor propellant systems. As a result of these activities, EAFB generates waste munitions, energetic solid rocket propellant and solid propellant contaminated waste laboratory materials. Edwards AFB uses open burn and open detonation units to treat these wastes. EAFB also generates hazardous waste from several on-site sources including maintenance and repair activities, research, and development programs, as well as cleanup of occasional chemical spills. These wastes are stored on-site at the Hazardous Waste Support Facility and are shipped off-site for treatment or disposal.