SEATTLE (AP) ' A powerful explosion tore through a Washington motel, critically injuring a gas company worker and knocking back firefighters just minutes after the manager evacuated the building because she could smell and hear a gas leak.Two people were unaccounted for of the roughly 65 guests at the Bremerton Motel 6, but they might not have been in the building at the time of the blast Tuesday night, said Al Duke, the city's fire chief. The search would continue until they were located, he said.The blast on the west side of Puget Sound, across from Seattle, ripped off a 16-room section of the hotel that collapsed in a pile of rubble and burned for hours. Some firefighters at the scene were blown back 20 feet by the force, and others pulled smoldering debris from the building to help contain the fire, Bremerton Fire Capt. John Hawkins said at a Wednesday news conference.Fire officials planned to go through the rubble carefully."The management did a really good job of getting the alarm in right away and getting the evacuation started," Police Chief Steve Strachan said.Acting manager Tonya Hinds said in a telephone interview that a passer-by came into her office to say a gas line was leaking at the back of the building. Hinds ' a former volunteer firefighter ' said she went outside and saw that the leaking line was a big one "with a lot of gas.""I pulled the alarm and started corralling people away from the building," Hinds said. "I wanted to make sure all my guests were out."The alarm came in just before 8 p.m., and the fire department and two Cascade Gas employees responded. The explosion came half an hour later, critically injuring one of the workers, who was flown to a Seattle hospital, Strachan said."Our prayers go out to his family. It could have been worse," an emotional Duke said at a news conference Wednesday.Two firefighters were injured in the blast, but both were home Wednesday and in good condition, Hawkins said. One firefighter suffered bruised ribs, and the other a concussion, Duke said.The three-story motel reopened last fall after an extensive remodel. Hinds said a guest reported seeing someone jump out a window and land on or near the gas line just before the leak.The Red Cross was helping find alternative housing for guests, Strachan said.The investigation is expected to take weeks, with help from the National Transportation Safety Board, which regulates gas pipelines.Join the conversation about this story Click here to read full news..