At about 10 a.m. on April 27, 1978, workers began raising the day's second bucket of concrete up 166 feet to Lift 29. Each day, they poured another 5-foot lift to build the second of two 430-foot cooling towers for the new Pleasants Power Station at Willow Island.
But on that Thursday morning, 30 years ago today, something went terribly wrong.
The cable hoisting that bucket of concrete went slack. The crane that was pulling it up fell toward the inside of the tower. Scaffolding followed. The previous day's concrete, Lift 28, started to collapse.
Concrete began to unwrap off the top of the tower. First it peeled counter-clockwise, and then in both directions. A mess of concrete, wooden forms and metal scaffolding crumbled to the ground.
Fifty-one construction workers were on the scaffold at the time. They all plunged to their deaths.
On April 27th 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.
The Occupational Safety and Health Administration (OSHA) investigation team arrived at the site the day of the accident. A team from the National Bureau Of Standards (now called National Institute of Standards and Technology) arrived two days later. Like most disasters, it's still hard to point to one specific triggering event. Instead, a mix of safety lapses combined to bring the tower crashing down.
Scaffold was attached to concrete that hadn't had time to sufficiently cure.
Bolts were missing and the existing bolts were of insufficient grade. See Bolted joint
Only one access ladder, restricting ability to escape.
An elaborate concrete hoisting system was modified without proper engineering review.
Contractors were rushing to speed construction
On June 8, 1978, OSHA cited Willow Island contractors for 10 willful and 10 serious violations. Among other things, the violations cited the failure to field test concrete and properly anchor the scaffold system.
OSHA proposed $108,300 in fines. The cases settled for $85,500, or about $1,700 per worker killed in the disaster.
OSHA referred the case to the United States Department of Justice for a criminal investigation. A grand jury was convened, but no charges were ever filed.