The Willow Island disaster was the collapse of a cooling tower under construction at a power station at Willow Island, West Virginia, on Thursday April 27, 1978. The falling concrete caused the scaffolding to collapse. 51 construction workers were killed. The Allegheny Power System was building a larger plant at Willow island, West Virginia. The new plant would have 2 generators with a total capacity of 1300 megawatts. This was in addition to the 2 smaller units that were already there. By April 1978 one natural draft cooling tower had been built, and a second was under construction.
On April 27, 1978 tower number 2 had reached a height of 166 feet (51 meters). Just after 10 AM, as the third lift of concrete was being raised, the cable hoisting that bucket of concrete went slack. The crane that was pulling it up fell toward the inside of the tower. The previous day's concrete, Lift 28, started to collapse. Concrete began to unwrap from the top of the tower, first peeling counter-clockwise, then in both directions. A jumble of concrete, wooden forms and metal scaffolding fell into the hollow center of the tower. Fifty-one construction workers were on the scaffold at the time. All fell to their deaths.
On the day of the collapse, an inspection team from the Occupational Safety and Health Administration (OSHA) arrived at the site and began an investigation into the collapse. A team from the National Bureau of Standards (NBS) join the the OSHA team two days later. NBS was requested to assist the field investigation conducted by OSHA at the site of the collapse and to carry out a detailed study aiming at the determination of the most probable cause of the collapse. In response to this request, NBS carried out field, laboratory and analytical studies.
Details of the NBS investigation can be found in the NBS report, "Investigation of Construction Failure of Reinforced Concrete Cooling Tower at Willow Island, West Virginia (NBS IR 78-1578)."