On Saturday, the Bureau of Land Management announced the results of its preliminary investigation into the fire. Details on how the fire started were not specified, only that it was likely started by a military training incident. The Utah National Guard and the Dugway Proving Ground are both conducting their own investigations.
The Pony Fire started around 10 a.m. on June 11 and burned 928 acres of BLM-managed lands. The fire was contained the next evening after burning about 1/3 south of a Tooele County road known as the Pony Express Road and about 3 miles north of the BLM campground at Simpson Springs.