Remarks: Smoke was noticed coming from a gas turbine exhaust stack. Valves on the WHRU and on the heat exchange system were found to be in the correct closed position. Flames started coming out of the exhaust, and the fire hoses were used to cool the unit. Gas and diesel fuel supplies were isolated, and the process systems were shut in. There continued to be hot spots on the exterior of the WHRU. A water wash was done. This dropped the temperature of the WHRU after three cycles. Heat exchanger fluid leaking into exhaust insulation was the cause.
 

Remarks: At some time prior to May 1, 1996, the four drain valves on the pig launcher were left in the open position. This may have happened during the last pigging operation which occurred March 16, 1996. On May 1, 1996, Platform Harmony had a shutdown due to a faulty circuit board on the fire and gas system, which in turn shutdown Platform Heritage. Heritage personnel decided to test shutdown valves and pressure operated valves on the pipeline and other valves that require a complete platform shutdown in order to perform these tests. One of the valves that was function tested was pressure operated valve 791-3. The operator noticed an air leak on the stem of the valve. He closed the valve and turned the air off. It appears that air leaked past the controller and reopened the valve (this valve is not a fail-safe close valve).
 

Remarks: Caused by a thrust-bearing failure, which allowed the shaft of the electric motor to rub against the seal assembly causing friction and heat.