Smoke was reported coming from the B Wing of Palo Verde Main on the Tempe campus Monday afternoon, according to ASU officials.
Students and faculty were evacuated for about 20 minutes, ASU Assistant Police Chief Jim Hardina said.
The cause of the smoke is still unknown, he added.
Tempe Fire Department spokesman Jim Schmit said the smoke was just in the hallway and once the doors were opened the smoke cleared out.
“We assume someone let off a smoke bomb or some sort of device,” he said.
Schmit said the smoke triggered the alarm, but no sprinklers were set off
The building sustained no damage from the smoke and no one was injured.
Reach the reporter at amrami13@asu.edu