Semi crash near Utah-Arizona border causes fire, backup on I-15 By: St. George News and last updated 2020-12-21 00:57:03-05 ST. GEORGE, Utah â A semitrailer crash slowed traffic and caused a one-acre fire Sunday afternoon on south Interstate 15 just past the Utah-Arizona border. The semitractor was hauling a box trailer from Hurricane to the Las Vegas area, St. George Fire Chief Robert Stoker told The truck slid off the right side of the road and hit the metal guard rail, which ruptured a fuel tank and caused a fire. The flames spread from the truck into the brush about one acre, but the fire department was able to control it and put it out, Stoker said.