1. SECTION 1431 OF THE SAFE DRINKING WATER ACT ( SDWA ), 42 U.S.C. SEC. 300I. 2. TENNECO OIL COMPANY LINCOLN COUNTY, OKLAHOMA 3. TENNECO OIL CO., ET AL., HAVE ENGAGED IN OIL AND GAS PRO- DUCTION ACTIVITIES ON THE SAC AND FOX NATION SINCE 1925. THE SAC AND FOX HISTORICALLY OBTAINED THEIR DRINKING WA- TER FROM THE VAMOOSA-ADA AQUIFER VIA WELLS LOCATED ON THE NATION. IN THE 1950S AND 1960S, THE SAC AND FOX BEGAN TO COMPLAIN ABOUT THE POOR QUALITY OF THEIR DRINKING WATER. THE WATER EVENTUALLLY BECAME SO CONTAMINATED WITH OIL- FIELD BRINE AND OTHER OILFIELD PRODUCTS THAT IT WAS UNFIT FOR HUMAN CONSUMPTION. 1N 1974, THE SAC AND FOX NATION LEASED PROPERTY AND DRILLED NEW DRINKING WATER WELLS INTO AN UNCONTAMINATED PORTION OF THE AQUIFER TWO MILES OFF THE RESERVATION. SAMPLING OF THE PORTION OF THE AQUIFER UNDERLYING THE SAC AND FOX NATION HAS INDICATED THE PRE- SENCE OF EXCESSIVE CONCENTRATIONS OF BENZENE, SODIUM AND CHLORIDE. THE CONTAMINATION OF THE VAMOOSA-ADA AQUIFER WAS CAUSED BY THE NEGLIGENT OIL AND GAS PRODUCTION ACT- IVITIES OF TENNECO OIL CO., ET AL., RESULTING IN THE MI- GRATION OF BRINE INTO THE AQUIFER THROUGH IMPROPERLY PLUGGED PRIMARY PRODUCTION, SECONDARY RECOVERY AND SALT WATER DISPOSAL WELLS AS WELL AS THE LEACHING OF BRINE IN- TO THE AQUIFER FROM THE SURFACE P