The following report is the independent product of the Accident Investigation Committee which was commissioned by the Department of Energy following the accident on September 21, 1978, at the Strategic Petroleum Reserve site at West Hackberry, Louisiana. This Committee is charged with the task of determining the nature, extent, and causes of that accident, which resulted in loss of life, injury and property damage, and the need for corrective action. A nonburning oil spill went into nearby Black Lake, but was contained by the deployment of a series of oil spill containment booms and a prevailing wind from the northeast that kept the oil spill in a restricted area near shore. Because of the rapid and effective containment and cleanup of the oil spill by the Rapid Response Team, it appears very likely at this time that Black Lake will not sustain any permanent environmental damage. Cavern 6 initially contained approximately 7,000,000 barrels of oil at a pressure of 650 psig measured at the well head. As of September 29, 1978, the Strategic Petroleum Reserve Office - New Orleans (SPRO) estimated that oil expulsion from Cavern 6 was 67,510 barrels. Of this, 34,620 barrels of oil are accounted for, including 31,200 barrels of oil released into Black Lake and subsequently recovered. The remainder (32,890 barrels) was assumed by SPRO to have been burned. The total loss is presently estimated by the Accident Investigation Committee 's consultant to be $12 million. An assessment of the technical problems present at the time of the accident is given. Recommendations for improved safety procedures are included.