Mohave Power Station - 1985 Pipe Failure Disaster

1985 Pipe Failure Disaster

On June 9, 1985, a 30-inch (760 mm) hot reheat line, under 600 pounds per square inch of pressure, burst open. The reheat line cycles steam back through the boiler stack after it has expanded through the high pressure (HP) turbine and before it reached the low pressure (LP) turbine. A 1,000-degree steam cloud blew down a door leading to the control room of the station, fatally scalding six workers: Michael Bowman, John Dolan, Ernest Hernandez, Terry Leroy, Danny Norman and Howard Turner. Ten others were injured. The station was out of service for six months while all the steam piping was replaced.

A report on the accident was completed in May, 1991, but was not released until Christmas Day because of Edison's objections that it would compromise civil suits.

Although several factors contributed to the pipe's failure, the report said Edison's actions—or lack of actions—were "primary and critical factors in causing the accident":

• Edison knowingly operated the system at temperatures above design specification for long periods of time, and operators were unable to control the temperatures within the system as a result of a "design flaw."

• Even so, the pipe, part of a steam reheat system, was not routinely maintained or inspected, though the pipe shifted and distorted because of exposure to abnormal stresses, the report said.

• Edison's management made high production a priority over safety. In 1979, Edison disciplined a supervisor for ordering an unauthorized inspection of unrelated pipe welds. "The fear SCE management has instilled in its employees is counterproductive to safety and increases the chances that additional incidents as serious as this one may occur in the future," the report said.

The report found no evidence that the accident was caused by a specific action on the day of the pipe failure.

The report recommended sweeping changes to Edison's policies, including annual reports to the PUC on the utility's safety training, inspection and maintenance programs. In addition, the report argues that, because the accident was avoidable, the costs should be borne by Edison's shareholders, not its rate-paying customers.