HOUSTON—An “ineffective” safeguard failed to prevent an explosive combination of air and fuel at a Husky Energy refinery in Superior, Wisconsin, leading to a blast and fire in the plant’s gasoline-producing unit in April, a U.S. industrial safety group said Dec. 12.
The April 26 explosion led to a massive fire and a 24-hour-long evacuation of residents living within miles of the plant. It was caused by air seeping through a hole in a valve within a fluidic catalytic cracking unit (FCCU), the U.S. Chemical Safety Board (CSB) said.
