THE WATKINS-JOHNSON COMPANY IS A CORPORATION, INCORPORATED IN THE STATE OF CALIFORNIA, THAT OWNS AND OPERATES A MANUFACTURING BUSINESS ON THE WATKINS-JOHNSON SITE AND HAS OWNED AND OPERATED IT SINCE APPROXIMATELY 1963. AT THIS FACILITY, WATKINS-JOHNSON COMPANY PERFORMED INDUSTRIAL ACTIVITIES, INCLUDING METAL MACHINING, DEGREASING OPERATIONS, METAL PLATING, AND PHOTOGRAPHY LABORATORY ACTIVITIES. WATKINS-JOHNSON HAS USED A VARIETY OF ORGANIC OR CARBON CONTAINING CHEMICALS, INORGANIC OR MINERAL ACIDS, AND METALS AT THE SITE. IN THE COURSE OF ITS OPERATIONS, WATKINS-JOHNSON COMPANY GENERATED A VARIETY OF WASTE SOLVENTS. WATKINS-JOHNSON COMPANY DISCHARGED LARGE VOLUMES OF WASTE SOLVENTS AT ITS FACILITY. SOLVENTS DISCHARGED BY WATKINS-JOHNSON LEAKED INTO THE SOIL AND MIGRATED TO THE GROUNDWATER. SOLVENTS IN GROUND- WATER HAVE BEEN DETECTED DOWNGRADIENT FROM THE SOURCE AREAS. MANY CONTAMINANTS HAVE BEEN DETECTED IN THE SOIL AND GROUNDWATER. THE CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD DISCOVERED CONTAMINATION IN THE GROUNDWATER AT THE WATKINS- JOHNSON SUPERFUND SITE IN 1984. AFTER ADDITIONAL TESTS WERE CONDUCTED, EPA IN AUGUST 1990, INCLUDED THE WATKINS- JOHNSON SUPERFUND SITE EPA'S NATIONAL PRIORITIES LIST.