The Oregon Department of Consumer and Business Services, Occupational Safety and Health Division (Oregon OSHA) has fined Siemens Power Generation a total of $10,500 for safety violations related to an Aug. 25, 2007, wind turbine tower collapse that killed one worker and injured another. The investigation found no structural problems with the tower, according to the agency; rather, the tragedy was the result of a system that allowed the operator to restart the turbine after service while the blades were locked in a hazardous position. The company has made changes to the tower's engineering controls to ensure it does not happen again, the agency said.
The event took place at the Klondike III wind farm near Wasco where three workers were performing maintenance on one of the turbine towers. After applying a service brake to stop the blades from moving, one of the technicians entered the hub of the turbine. He then positioned all three blades to the maximum wind resistance position and closed all three energy isolation devices on the blades. The devices are designed to control the mechanism that directs the blade pitch so that workers don't get injured while they are working in the hub. Before leaving the confined space, the worker did not return the energy isolation devices to the operational position. As a result, when he released the service brake, wind energy on the out-of-position blades caused an "overspeed" condition, causing one of the blades to strike the tower and the tower to collapse, the Oregon OSHA investigation found.
A worker working at the top of the tower died in the collapse. Another worker, who was on his way down a ladder in the tower when it collapsed, was injured. The third worker was outside the tower and unharmed. During the investigation, Oregon OSHA found several violations of safety rules:
The company has 30 days to appeal the citation.