Spills ≥ 50 Barrels (2,100 gallons) – 1995

January 25, 1995 - Mesa Operating Co.

Remarks: There were two storage tanks containing condensate located on the platform. A workboat struck the platform causing these tanks to rupture.

July 6, 1995 - Coastal Oil & Gas Corporation

Remarks: Failure of the condensate surge pump was the initial malfunction. However, numerous failures of the Surface Safety System occurred prior to the discharge of oil to the OCS waters. The following equipment failed: condensate pump shut down, surge vessel level safety high (LSH), sump tank LSH, Master control relay for the sump tank, Master control relay for the master panel. Extremely wet fuel and supply gas contributed to the failures. Ultimately, condensate carried through the sump tank water leg and into OCS waters.

NRC Report: 298669

October 3, 1995 - Meridian Oil Offshore, Inc.

Remarks: EXPLORATION SPILL. A weather change caused the motor vessel to drift into the port leg of the drilling rig resulting in punctures to the saddle tank of the boat and the release of approximately 89 bbl of diesel fuel. Due to rough weather and sea conditions, no attempt was made by the boat company to recover the spilled fuel. There was no damage to the drilling rig, and the boat returned safely to shore.

December 15, 1995 (2 days) - Chevron U.S.A. Inc.

Remarks: On December 14, 1995, a high-pressure separator on Platform A, and unmanned platform, was cleaned in an effort to reopen the separator's clogged water leg. Upon returning to the platform on December 15, the platform operators observed liquid hydrocarbons were spilling from the platform's sump tank and that a ball valve on the drain line from the separator to the sump tank was not holding. The valve, which had been opened and closed during the previous day's cleaning of the separator, was removed, and the line was blind flanged. The cause of the spill was the overflow of liquid hydrocarbon production from the thief hatch and water leg of the platform's sump tank. Contributing causes were: ineffective level safety high (LSH) configuration; and deformed valve stem which allowed the separator drain line valve to remain slightly open. Once production was restored, gas, water, and condensate began to cut out the ball valve and body and allowed an increasing flow of production to the sump tank. Two methods were employed to estimate volume of condensate spilled resulting in an estimate between 436 and 650 barrels. However, due the greater reliability of the average allocation meter method, 436 bbl was selected.

OCS Report: MMS 96-0038

NRC Report: 317241 and 317341

Last Updated: 10/19/09, 11:52 AM