THIS IS A UNILATERAL ADMINISTRATIVE ORDER (UAO) PURSUANT TO RCRA 7003 ISSUED TO CHEVRON U.S.A. INC., EXXON MOBIL CORP., ATLANTIC RICHFIELD COMPANY, CONOCO, INC., KAYO OIL COMPANY, DOUGLAS OIL COMPANY OF CALIFORNIA, UNOCAL CORPORATION, MOBIL OIL CORPORATION, TOSCO CORPORATION, THRIFTY OIL CO., BEST CALIFORNIA GAS LTD., KAZUHO NISHIDA, HLW CORPORATION AND WINALL OIL COMPANY. IN AUGUST 1995, THE CITY OF SANTA MONICA FOUND THE GASOLINE ADDITIVE MTBE IN ITS CHARNOCK (MUNICIPAL WATER SUPPLY) WELLFIELD. THESE RESPONDENTS, WITH RESPONDENTS TO AN EARLIER EPA ADMINISTRATIVE ORDER ON CONSENT (AOC) ISSUED ON NOVEMBER 30, 2000 (SHELL OIL COMPANY/SHELL OIL PRODUCTS COMPANY/EQUILON ENTERPRISES LLC), HAVE RESPONSIBILITY FOR RELEASES OF MTBE AND OTHER GASOLINE CONSTITUENTS THAT ARE CONTRIBUTING TO ENDANGERMENT OF PUBLIC HEALTH AT THE WELLFIELD. THE PRESENT ORDER REQUIRES THE RESPONDENTS TO PARTICIPATE AND COOPERATE (P&C) WITH THE SHELL PARTIES IN PERFORMING INITIAL REGIONAL RESPONSE ACTIVITIES THAT WILL ASSIST EPA AND THE LOS ANGELES REGIONAL WATER QUALITY CONTROL BOARD IN SELECTING APPROPRIATEE REGIONAL REMEDIES AND IN DETERMINING IF THERE IS A BETTER ALTERNATIVE THAN THE CURRENT METHOD OF WATER REPLACEMENT.