ON 7/17/95, A RELEASE OF OIL OCCURRED WHEN A CHECK VALVE SEPARATING AN ACTIVE PORTION OF A 4 CRUDE OIL GATHERING LINE FROM AN INACTIVE LINE FAILED AND CRUDE OIL LEAKED OUT OF A CORRODED SECTION OF THE ABANDONED LINE. THE DISCHARGE TOOK PLACE ON BOTH PRIVATE AND GOVERNMENT LANDS. THE CRUDE OIL REACHED THE SOIL SURFACE AND FOLLWED A DRAW DOWNHILL TOWARDS LAKE SAKAKAWEA. APPROXIMATELY 100 TO 150 BARRELS OF OIL WERE RELEASED TO THE LAND; OF THESE, AN ESTIMATED 15 TO 20 BARRELS ACTUALLY FLOWED INTO THE WATER.