http://www.cnn.com/2010/US/02/07/connecticut.explosion/index.html?hpt=T1 (CNN) -- An explosion at a Connecticut power plant has caused "mass casualties," authorities said. The blast happened about 11:30 a.m. Sunday at the Kleen Power Plant in Middletown, a suburb of Hartford. The plant's general manager, Gordon Holk, confirmed the blast caused casualties, but wasn't sure how many. Fire and police officials in Middletown said there were "mass casualties," but no other details were immediately available. The site is a 620-megawatt gas-fired power plant, according to Holk.