The Seattle Times via Associated Press, Christine Clarridge
Debris rests on the ground after a portion of Motel 6 exploded, just after the business had been evacuated due to reports of a gas leak, Tuesday, Aug. 18, 2015, in Bremerton, Wash. Manager Tonya Hinds said in a telephone interview that a passerby had come into her office to say a gas line was leaking at the back of the building.

SEATTLE — An explosion demolished part of a Motel 6 in Bremerton, Washington, critically injuring a gas company worker just minutes after the acting hotel manager had evacuated the building because she could smell and hear a gas leak.

Two people were unaccounted for out of the hotel's roughly 65 guests, but they may not have been in the building at the time of the blast Tuesday night, Bremerton Fire Chief Al Duke said. The search would continue until they were located, he said.

The blast west of Seattle tore off a 16-room chunk 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," Bremerton Police Chief Steve Strachan said.

Manager Tonya Hinds said in a telephone interview that a passer-by had come 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, said Hawkins of the fire department. One firefighter suffered bruised ribs and the other a concussion, Duke said.

The blast destroyed 16 rooms of the motel, which reopened last fall after an extensive remodel, officials and hotel managers said. Hinds said one guest reported having seen someone jump out a window of the three-story building and land on or near the gas line just before the leak.

The Red Cross was helping find alternative housing for hotel guests, Strachan said.

The investigation is expected to take weeks, with help from the National Transportation Safety Board, which regulates gas pipelines.