Camp Lejeune officials first became aware that volatile organic compounds (VOCs) were interfering with the analysis of drinking water samples in 1981 that were being collected to comply with future drinking water standards. In 1982 and 1983, continued testing identified two VOCs--trichloroethylene (TCE), a metal degreaser, and tetrachloroethylene (PCE), a dry cleaning solvent--in two water systems that served base housing areas, Hadnot Point and Tarawa Terrace. There were no regulatory standards at the time and Base officials did not know the source of VOCs; water treatment plants and piping infrastructure were investigated as the source. In 1984 and 1985, a Navy environmental program identified VOCs in some of the individual wells serving the Hadnot Point and Tarawa Terrace water systems. The affected wells were subsequently removed from service. Department of Defense (DOD) and North Carolina officials concluded that on- and off-base sources were likely to have caused the contamination.