A pipe failure is being blamed for Wednesday night's explosion and fire at the Holly refinery, 398 S. 800 West in West Bountiful. And company officials say it was a pipe that was already earmarked to be replaced.
Just before 9 p.m., a crack in one of the pressure release lines resulted in a leak and explosion that sent a fireball into the sky. It was a pipe in which the company already had discovered a small flaw the day before, said company spokesman Mike Astin.
"It was a pipe that we were scheduled to replace this summer," he said.
Once the crack was discovered, plans were made to move up the repair schedule and replace it Thursday morning. The company was already in the process of shutting down that unit, Astin said, but the crack apparently grew faster than anticipated.
"It didn't get shut down or repaired before it opened up," he said. "We do periodic maintenance at the plant. We knew we needed to replace it. We were watching it."
The refinery also has suffered two power outages within the last week, which could have placed additional pressure on the system and accelerated the weakening of the pipe, said South Davis Metro Fire Chief Jim Rampton.
The line was completely isolated by 2 a.m. Thursday, Astin said. That unit, which helps make high-grade gasoline, was expected to remain shut down for at least a week as the company explored repair and replacement options. But the remaining blend stocks were still in operation Thursday, Astin said.
It will cost an estimated $375,000 to replace the line, he said, but it was money the company already had budgeted for and was planning to spend in the summer to replace it.
A fire hose was already in position as a precaution prior to Wednesday's explosion because of the crack. Astin believes safety precautions and procedures put in place by the refinery, and the good work of the South Davis Metro Fire Department, prevented the situation from being worse.
"All the safety systems worked just like they were supposed to," he said.
The only reported injury was a worker who fell off a truck due to the force of the blast. The man was treated for minor injuries.