A fire at a heating building on Factory Street caused power to be cut to campus buildings on the West Side of Ohio University.
Fire crews from the Athens Fire Department and the Richland Area Volunteer Fire Department were on the scene fighting electrical fires that had begun because of the bad switch.
The official cause has not been determined by fire officials.
"We had trouble getting the power killed to the area," said Athens Fire Chief Robert Troxel on Monday night. "We have the fire knocked down now and we're just controlling it."
The explosion created heavy smoke with unknown chemicals in it, according to Troxel.
Firefighters cut out part of a wall at the back of the plant to get to the fire and were using carbon dioxide fire extinguishers to put out the blaze.
"I don't know how many we've used but we've used a lot," Troxel said.