Students were stopped in their tracks yesterday as they watched black smoke billow into the sky southwest of campus.

Although the smoke appeared to be close to campus, it was actually rising from an insulation plant that caught on fire near Armory Park.

Firefighters were called to ABC Roofing Supply, 535 E. 16th St., early yesterday when insulation in the plant’s materials yard caught on fire from fallen electrical lines, said Tucson Police Department Officer Mario Cruz.

“”Fire investigators told me there is a witness who said a large dust devil came through the yard, shot something up that hit the power lines, causing it to arc and explode and hit the ground, causing a fire,”” Cruz said.

Within a half-hour the fire was contained, and firefighters sprayed the remaining burning materials from the ladder of a fire truck.

TPD officers directed traffic because power to traffic signals in the area lost power.

Cruz said fire investigators were still talking to the witness, but they were ruling it as an accidental fire.

He said he knew of no injuries caused by the fire.