MOBIL OWNS AND OPERATES SEVERAL UNDERGROUND STORAGE TANKS (USTS) AT AN AUTOMOBILE SERVICE STATION LOCATED AT THE CROSS KEYS INTERSECTION IN DOYLESTOWN, PENNSYLVANIA. HIGH LEVELS OF GASOLINE CONSTITUENTS, RESULTING FROM LEAKING USTS, HAVE BEEN DOCUMENTED TO BE PRESENT IN SEVERAL ON-SITE MONITORING WELLS. WITHIN 1000 FEE DOWN-GRADIENT OF THE MOBIL FACILITY IS A NEIGHBORHOOD OF RESIDENCES WHICH RELY ON PRIVATE WATER SUPPLIES. THE TOXIC CONSTITUENTS APPEAR TO BE MIGRATING IN THE DIRECTION OF THE PRIVATE WELLS. THE ORDER ON CONSENT REQUIRES MOBIL TO CONDUCT ROUTINE MONITORING AT SEVERAL OF THE PRIVATE WATERS TO ASSURE THEIR SAFETY. IF EPA EVER DETERMINES THAT ANY OF THE PRIVATE WATER SUPPLIES ARE UNSAFE, IT MAY REQUIRE MOBIL AND OTHER RESPONSIBLE PARTIES IN THE AREA TO FURNISH AN ALTERNATE WATER SUPPLY TO THE IMPACTED RESIDENTS.