PCE (perchloroethylene or tetrachloroethylene) was the main contaminant. The maximum level detected in drinking water was 215 parts per billion (ppb) in February 1985. The source of contamination was ABC One-Hour Cleaners, an off-base dry cleaning firm. The most contaminated wells were shut down in February 1985. Water modeling that ATSDR conducted for PCE complete. PCE concentration exceeded the current limit of 5 ppb in drinking water at the Tarawa Terrace water treatment plant for 346 months during November 1957-February 1987.