AUBURN – A worker was sent to the hospital when he was hit in the face by an explosive blast of air, oil and metal bits at about 8:30 a.m. Monday atop Auburn Hall.

Stanley Palmer, 22, of Lewiston was taken to Central Maine Medical Center and treated for injuries to his knee and face after being blasted by air from a ventilation system pipe. He was released Monday afternoon, according to a CMMC spokesman.

“There was so much air coming out of such a small space, it made quite an explosion,” Fire Prevention Officer Pete Simard said. “But there was no fire or heat. Just a lot of pressure.”

Palmer was one of several subcontractors working on the heating and air conditioning system on Auburn Hall. Simard said crews began testing the lines Friday. Palmer went to the roof of the newly constructed building to check one of the 6-inch pipes early Monday morning.

“Most likely it had been left, charged with air, all weekend,” Simard said. Palmer removed a metal cap on the pipe, and all of the air came rushing out. The metal cap hit him in the knee and his face and neck were blasted with air, water, oil and metal shavings.

“He was was wearing his helmet and his goggles,” Simard said. “But those pipes get filled with that stuff when they are being worked on. All that hit him in the face, so they are checking him for pieces of shrapnel. But otherwise, he’s OK.”

Simard said he has closed his investigation. Contractors will continue looking for a cause, he said.

“They want to know why it was charged and how long it had been left that way,” Simard said. “And then, why the men working on it were not notified.”