When a truck explosion defied science and left a crater in a Utah highway

Twenty years ago this month, Utahns were puzzling over a question that took almost a decade to answer: How could a single truck explosion be big enough to blast a whole crater into a mountain?

• This is Old News, where we dig through the wreckage of Utah history.

What drove the news: On Aug. 10, 2005, a truck carrying mining explosives rolled over near the mouth of Spanish Fork Canyon, detonating 35,500 pounds of cast boosters.

• The explosion left a 70-foot crater in the highway, ripped rail tracks out of the ground and shot debris a quarter-mile away, causing some brushfires.
• No one was killed — passersby pulled the driver and his passenger from the wreck just before the blast — but at least 20 people were injured.

The intrigue: No one was surprised that a truckload of explosives went boom. But the scale of its power was astonishing, blowing the sunglasses off people's faces 10 miles away.

Friction point: That wasn't supposed to happen, University of Utah researchers wrote in a study of the blast.

• The boosters were designed to deflagrate, rather than detonate — a slower, far less violent reaction, they wrote.

How it worked: After years of computer simulations, researchers concluded the explosives were either damaged or simply packed too tightly into the truck.

The bottom line: That research helped identify safer ways to pack and transport explosives.

Previously in Old News

• When "The Book of Mormon" musical opened in Utah
• A pyrrhic victory for environmentalism
• Sally Hemings and Thomas Jefferson: Sealed for eternity?
• Naked lady steals, crashes police cruiser
• Olympic scandal