THIS UAO PURSUANT TO RCRA 7003 IS ISSUED TO CHEVRON U.S.A. INC., EXXONMOBIL CORPORATION, ATLANTIC RICHFIELD COMPANY, CONOCO INC., KAYO OIL COMPANY, DOUGLAS OIL CO. OF CALIF., UNOCAL CORPORATION, MOBIL OIL CORPORATION, TOSCO CORP., THRIFTY OIL COMPANY, BEST CALIFORNIA GAS LTD., KAZUHO NISHIDA, AND HLW CORPORATION. IN AUGUST 1995, THE CITY OF SANTA MONICA FOUND THE GASOLINE ADDITIVE MTBE IN ITS CHARNOCK MUNICIPAL WATER WELLFIELD. THE RESPONDENTS, WITH RESPONDENTS TO AN EPA UAO ISSUED ON SEPTEMBER 22, 1999 (SHELL OIL COMPANY/SHELL OIL PRODUCTS COMPANY/EQUILON ENTERPRISES LLC), HAVE RESPONSIBILITY FOR RELEASES OF MTBE AND OTHER GASOLINE CONSTITUENTS THAT ARE CONTRIBUTING TO THE ENDANGERMENT AT THE WELLFIELD. THE ORDER REQUIRES RESPONDENTS TO PARTICIPATE AND COOPERATE WITH THE SHELL PARTIES IN PROVIDING REPLACEMENT WATER TO THE CITY OF SANTA MONICA AND SOUTHERN CALIFORNIA WATER CO. FOR A PERIOD OF FIVE YEARS.