ORONO – The State Fire Marshal’s Office is still investigating the cause of Thursday night’s fire at the former Birch Street School, but it’s not considered suspicious, Fire Chief Buddy Webb said Friday.

Fire marshal investigators are expected to be back at the scene today.

The fire caused roughly $10,000 in damage to the back stairwell area.

“It got up into the attic a little bit, but not a lot,” Webb said. No one was in the building at the time of the fire.

The former school, which houses the town’s senior center and thrift shop, was being renovated and updated to meet new building codes and to make the facilities accessible to people with disabilities.

There was some damage to work that recently had been completed, mainly to the sheet rock, Webb said. “We were very lucky,” he said.