By Catherine Tsai
The Associated Press

AP Photo/David Zalubowski Firefighters search through the rubble of the restaurant that collapsed after an explosion in the old town part of Pueblo, Colo., on Thursday.

PUEBLO, Colo. — An explosion laid waste to a restaurant and a shop Thursday in downtown Pueblo, killing one person, injuring at least seven and forcing several blocks to evacuate. Crews pulled a survivor from the rubble more than four hours after the blast.

The cause of the blast was being investigated. At least one witness said she smelled gas, and buildings for several blocks in all directions were evacuated.

The person who died was one of two women rescued from a shop next to the Branch Inn restaurant, said Fire Chief Chris Riley.

Firefighters dug a man out of the rubble of the restaurant around 6:30 p.m. Riley said he was conscious and talking.

A total of seven people, including the woman who died, were transported to the hospital. An eighth person went unassisted later, Fire Department spokesman Woody Percival said. He didn't know the conditions of the patients.

Authorities did not know whether the restaurant was open when the explosion occurred or how many people were inside. Crews were searching the buildings for anyone else who might be trapped inside, Percival said.

Smoke still rose from the rubble hours after the explosion. Glass block, bricks and other debris were strewn more than 100 feet from the restaurant. The third-floor windows of an apartment across the street were blown out.

The Branch Inn sign lay on its side in the street, and an odor of burnt plastic filled the air. The blast blew the restaurant's front door into an intersection, where a hinge lodged in the fender of a sport utility vehicle waiting at a stop sign.

The SUV driver, 35-year-old Christine Guerin, said she was looking for a business when she heard an explosion and saw glass flying toward her.

"You couldn't even see the building. It was just smoke, black smoke," she said, saying she could hear a hissing noise and smelled gas after she got out of her car.

Police quickly arrived quickly and began escorting people away.

Percival did not know what type of business was in the adjacent building. He said the neighborhood is dotted with boutiques that sell clocks, antiques, clothing and gifts.

"I don't recognize what's there," he said.

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Pueblo, a city of about 106,000, is 100 miles south of Denver.