Most residents along Utah County's Wasatch Front were awakened early Monday by an explosion at the Ireco Inc. explosives plant west of Utah Lake.
But quick thinking by plant employees prevented any injuries.The 4:35 a.m. blast was caused when 40 pounds of nitrate salt mixture exploded and detonated another 2,000 pounds of nearby explosives in Ireco's 1-A building. More than 3,000 pounds of a non-explosive nitrate oxidizer also was in the building.
According to Ireco vice president Jay Anderson, the specialty explosives emulsion was being mixed when four employees noticed the product was heating. They turned off all the equipment and evacuated the building.
"It appears the product heated up and a detonation resulted," Anderson said.
The explosion occurred when the four employees - three workers and a security guard - were about 75 yards from the building. The blast blew the rear window out of the truck in which they were fleeing, but no one was injured.
"The employees acted properly and evacuated the site," Anderson said.
He said a piece of equipment likely malfunctioned, causing the product to overheat. The plant featured newly reinforced walls, which helped contain the blast within the building.
Located between Lehi and Elberta on U-68, Ireco manufactures explosives used for mining.
A Jan. 25, 1983, explosion at the plant killed four employees. Anderson said the company no longer manufactures the product that caused that explosion.
Monday's explosion was felt throughout Utah Valley and shattered windows in several businesses from Lehi to Provo as the shock waves traveled eastward over Utah Lake. Utah County sheriff's dispatchers were flooded with calls from as far away as Spanish Fork and Benjamin immediately after the blast, but no other damage was reported.
Emergency officials were expected to keep U-68 and all roads to the area closed Monday while waiting for a fire at the site to burn out. Anderson said all the explosive material in the building likely detonated and no further explosions should occur. However, officials will not go on the site until they know it's safe.
Utah County investigators and officials from OSHA and the Bureau of Alcohol, Tobacco and Firearms are due at the site Tuesday.
As daylight broke about 6:45 a.m., a dark cloud of smoke rose from the blast area. Concerned that the smoke might be toxic, officials were considering possible evacuation procedures before determining the smoke was not dangerous and was likely due to burning of an oil-based material.
Deseret News staff writer Scott Taylor contributed to this report.