SLIPPERY ROCK — Multiple fire departments responded to an emergency call Tuesday night at Slippery Rock University's Patterson Hall which forced the evacuation of a number of students.

“When we were in there, we noticed the building was really hot,” said Caitlin Dunn, an SRU junior. “The fire alarm started going off, so we went out.”

Dunn was in the building with a group of five students who were working on a school project before leaving the building at about 9:45 p.m.

“When we were going down the stairwell, we noticed a gassy type of smell, but nothing we knew,” Dunn said.

Ryan Hanchosky, chief of Slippery Rock Fire and Rescue Team, which coordinated the emergency crews, said smoke and haze filled the basement, first and second floors of the building.

“We are unsure of where the smoke came from,” Hanchosky said.

Hanchosky said SRU police officers arrived on the scene first and reset the alarm system, which made it difficult to tell where the smoke originated.

Hanchosky said after arriving, firefighters did not find any flames, and looked around for the source.

“I believe it's an air duct unit that burnt a belt and pushed the haze through the ducts,” Hanchosky said.

He said SRU's maintenance department was called to the scene once it was cleared.

He said everyone inside the building exited unharmed.

“The (college's community adviser) had everybody out here and accounted for,” Hanchosky said.