Corrective Action Unit (CAU) 516 is located in Areas 3, 6, and 22 of the Nevada Test Site. CAU 516 is listed in the Federal Facility Agreement and Consent Order of 1996 as Septic Systems and Discharge Points, and is comprised of six Corrective Action Sites (CASs): CAS 03-59-01, Bldg 3C-36 Septic System; CAS 03-59-02, Bldg 3C-45 Septic System; CAS 06-51-01, Sump and Piping; CAS 06-51-02, Clay Pipe and Debris; CAS 06-51-03, Clean Out Box and Piping; and CAS 22-19-04, Vehicle Decontamination Area. The Nevada Division of Environmental Protection (NDEP)-approved corrective action alternative for CASs 06-51-02 and 22-19-04 is no further action. The NDEP-approved corrective action alternative for CASs 03-59-01, 03-59-02, 06-51-01, and 06-51-03 is clean closure. Closure activities included removing and disposing of total petroleum hydrocarbon (TPH)-impacted septic tank contents, septic tanks, distribution/clean out boxes, and piping.