The Boston Globe just reported:
Emergency management officials say sirens in a 10-mile area around the Vermont Yankee nuclear power plant were inadvertently activated by a plant contractor for about three minutes. There’s no emergency at the plant, which is off-line for refueling.
The sirens went off about 11:30 a.m. Wednesday. The area around the power plant is called the Emergency Planning Zone. Plans have been developed for warning and protecting people within this area, which includes about 20 towns in Vermont, New Hampshire and Massachusetts.