UNOCAL CHEMICALS DIVISION OF UNION OIL COMPANY OF CALIF. OWNS/OPERATES A CHEMICAL STORAGE & DISTRIBUTION FACILITY AT 13TH STREET AND RIO COURT IN DENVER, CO. THE SITE IS UNDERLAID BY PUBLIC UTILITY CONDUITS AND STORM SEWERS AND HAS MANY MANHOLES. THE STORM SEWERS DISCHARGE INTO CHERRY CREEK AND THE SOUTH PLATTE RIVER. TOLUENE AND NAPHTHA-LIKE SUBSTANCES WERE FIRST IDENTIFIED UNDER THE SITE IN FEB. 1983. TESTS SHOWED HIGH LEVELS OF TOLUENE, TCE, PCE, DCE, AND OTHER NAPHTHA-LIKE SUBSTANCES (TESTS INCLUDED AIR MONITORING OF UNDERGROUND VAULTS, SOIL VAPOR ANALYSIS AND WATER SAMPLING). AS MUCH AS 2 FEET OF THIS PRODUCT HAVE BEEN FOUND SITTING ON TOP OF THE WATER TABLE AND LEVELS OF TOLUENE VAPORS WERE FOUND TO BE AS HIGH AS 1000PPM. EPA MONIOTRING DATA INDICATES THAT THE SOURCE OF CONTAMI- NATION IS THE UNOCAL FACILITY. RESPONDENT WAS OFFERED THE OPPORTUNITY TO PERFORM NECCES- SARY REMOVAL ACTIONS UNDER AN AO, BUT RESPONDENTS FAILED TO NEGOTIATE IN EARNST.