WOODS CROSS — The video is silent but violent. A truck drives away from an area about to be engulfed in flame.
Twenty-three seconds after the truck leaves the area, a pipe bursts, spewing a cloud of 800-degree hydrogen gas within 9 feet of an open flame.
Instantly, the hydrogen ignites, erupting into a fireball estimated to be 100 feet high. The fire then continues to burn for several minutes.
What the video doesn't show is the four men who were working nearby and blown to the ground but not seriously injured.
It doesn't show the extent of damage at the nearby Morningside subdivision, where four homes were severely damaged, and two of them were deemed uninhabitable. At least 100 other damage claims are being processed.
The Nov. 4 explosion at Silver Eagle Refining is the third refinery incident in Utah this year being investigated by the U.S. Chemical Safety Board. The board also plans to look at how refineries are regulated in Utah. The three Utah incidents account for 20 percent of the board's 15 investigations this year.
"As a percentage, that is a high number," said Don Holmstrom, the board's lead investigator for the Nov. 4 explosion at Silver Eagle, as well as for a Jan. 12 explosion at the same refinery that injured four workers.
The third Utah incident occurred Oct. 21 at the Tesoro Corp. refinery in Salt Lake City, when a pool of crude oil caught fire and spread to become a three-alarm blaze, damaging several trailers and equipment. Interstate 15 and FrontRunner commuter train service near the scene were briefly closed. The Silver Eagle refinery in Woods Cross is currently in the process of shutting down its fifth and final processing unit so it can begin a wall-to-wall inspection of its infrastructure.
"The frequency of accidents at U.S. refineries is very troubling," said U.S. Chemical Safety Board Chairman John Bresland, who spoke to the media Tuesday in Woods Cross. "The current rate of accidents is not sustainable, and it is not acceptable."
Bresland called on refineries to redouble their commitment to safer operations and safer communities.
Holmstrom said refineries are supposed to have a mechanical integrity program that identifies when certain equipment and materials are maintained or replaced when necessary.
"Our investigation to date indicates that the Silver Eagle refinery was operating with a mechanical integrity program that had some serious deficiencies," Holmstrom said.
In a statement released Tuesday evening, Silver Eagle re-emphasized that it is sorry for the explosion and is grateful no one was injured.
"Silver Eagle has been following an established mechanical integrity program and disagrees with any suggestion or assertion to the contrary," according to the statement. "It is apparent to the refinery that the program was insufficient and that changes need to be made."
Silver Eagle has also worked hard in recent years to upgrade the refinery and improve safety, refinery officials said.
Holmstrom agreed and credited the refinery with dismissing a previous consultant when it was determined that certain inspections were inaccurate.
Some measurements showed the pipe that failed on Nov. 4 was thinner than previously measured and that other pipes and vessels have no documented thickness readings.
The refinery says it has hired an internationally renowned industry consulting firm to help with its current investigation and get proper thickness measurements during the shut-down period.
Safety-board officials don't expect employees to lose their jobs. Rather, there will likely be more work as operators move into maintenance.
It's too early to determine the financial cost — damage to homes and the refinery — of the Nov. 4 explosion, Bresland said.
But the economic cost to the refinery, which is capable of processing 10,000 barrels of oil a day, is significant.
Tuesday's crude-oil price was $79.14 per barrel, meaning the refinery is missing out on as much as $791,400 worth of product a day.
Holmstrom said his team will be in Utah for the rest of the week and will likely make return trips as it compiles information and interviews for a final report.
He and Bresland said they also plan to investigate how the refinery managed to operate without a robust mechanical integrity program, how residential housing came to be located so close to potential refinery explosions and whether existing guidelines for siting hazardous facilities provide enough protection for residents.
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