The 3,452-acre McClellan Air Force Base (Ground Water Contamination) site was established in 1936 and operated as an Air Force Logistics Command Base until 2001. Its primary mission included management, maintenance and repair of aircraft, electronics and communication equipment. The operation and maintenance of aircraft have involved the use, storage and disposal of hazardous materials, including industrial solvents, caustic cleansers, paints, metal plating wastes, low-level radioactive wastes and a variety of fuel oils and lubricants. The Air Force has identified 326 waste areas of known and suspected contamination. The site’s long-term cleanup is ongoing.