An arson incident in the first-floor men’s restroom of Marston Hall resulted in the evacuation of the building Thursday morning.

Ames Assistant Fire Chief Phil Harris said someone ignited toilet paper which set off the fire alarms about 10 a.m. He said the damage to the building was minimal, and no one was injured. Ames Fire Department officials are conducting an investigation. The cost of the damages wasn’t immediately available.

Students, faculty and staff filed outside after hearing the alarms. Harris said fire officials had a difficult time finding the source of the smoke. It was first suspected that a bad pump in the basement was the cause. Department of Public Safety officials told the crowd of about 50 people outside the building that Marston Hall would most likely be sealed for the day.

The people were allowed to go inside in small groups to gather their belongings about an hour later. The building was reopened shortly before 1 p.m. after firefighters discovered the restroom. Harris said the fire was already out when it was discovered.

David Holger, assistant dean of engineering and Marston Hall supervisor, said he was relieved that it didn’t turn out to be a major fire. “I am glad that Marston Hall wasn’t severely damaged, but I’m disappointed that it was possibly someone from the ISU community who did this,” he said.

When Holger evacuated the building he took his cap and gown with him because he wasn’t sure if he could get back in the building. Faculty members standing outside the building joked that he was taking the fire a little too seriously. He needed the outfit for a Thursday night ceremony in the Scheman Building.

Eric Sjoberg, a freshman in engineering, had just sat down in Engineering 170 when the alarms went off. He said the alarms sounded for about 20 minutes as people filed outside.

“We had a test and my stuff’s still up in the classroom,” he said. “When I entered the building I could faintly smell smoke coming out of the building.”

Holger said many staff members were sent home for the day and many afternoon classes were scheduled for other buildings or cancelled. Faculty members, he said, went to other offices while firefighters investigated the fire.