New London — The Holiday Inn was evacuated briefly tonight after steam and heat in a second-floor laundry room set off a smoke detector.

The system that vents heat and water vapor from the dryers had become detached from them, causing vapor to build in the room, New London Fire Battalion Chief Marc Melanson said.

“The detector activated when it picked up all the moisture-laden warm air,” he said.

The smoke alarm set off a general activation alarm and the hotel was evacuated shortly before 8 p.m.

“Actually, the detector did its job,” Melanson said. Firefighters vented the laundry room and allowed people back inside in less than an hour.