A wildfire that burned down 15 buildings near the town of Wickenburg, Arizona, two months ago and cost nearly $1 million to fight was caused by railroad work, authorities said Monday.

Investigators found a section of cut track from work along the BNSF rail line, the Arizona Department of Forestry and Fire Management said. Investigators concluded the Rose Fire was sparked by sparks from a welder, grinder or torch used to cut the track, said Tiffany Davila, spokeswoman for the department.

Based on the way the fire moved away from the tracks, they were able to determine that this area was where the fire started.

“Fires along our rail line are rare, but we work hard to prevent them,” BNSF spokesman Kendall Sloan said in a statement. “In the rare event that fires do occur, we assist local communities with firefighting efforts and provide assistance to affected communities.”

“We remain committed to learning from this incident by continuing to reduce the fire risk around our tracks and working closely with local authorities throughout the fire season,” Sloan added.

The 266-acre wildfire began on June 12 and was fully contained five days later, according to Davila, with an estimated cost of $971,000.

The fire also destroyed 12 vehicles, a horse trailer and a motor home. US 60, the main route between the Phoenix metropolitan area and Las Vegas, was temporarily closed.

Wickenburg is located about 60 miles (97 kilometers) northwest of Phoenix.

Watch the player above to see ABC15’s coverage of the Rose Fire.