KING-TV, Seattle

SEATTLE — Nine firefighters were injured when an apparent natural gas explosion destroyed several buildings in Seattle early Wednesday morning, authorities said.

City officials said Wednesday afternoon that the explosion was accidental, but investigators are still determining where the gas leak occurred.

A gas leak was first reported at 1:04 a.m. Pacific Time. The explosion tore through the city's Greenwood neighborhood, north of downtown Seattle, 39 minutes later.

Firefighters had already responded to the leak when the blast and fire occurred.

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The firefighters went to the hospital with minor injuries mostly involving cuts and abrasions. All nine were released by 8 a.m.

It was believed at least three businesses were destroyed and a bike shop was heavily damaged. Several other neighboring buildings had their windows blown out.

"I arrived pretty soon after the massive fire trucks, and at that point, there were tons of flames leaping over what was already the rubble of Neptune Coffee, which as you can see now totaled, gone," said Davey Oil, owner of bike shop G&O Family Cyclery. "We work pretty hard on our business and we really love the neighborhood. Our block is a pretty close-knit block and this is pretty terrible."

Chocolati Cafe manager Darla Weidman said she's relieved it happened overnight instead of 11 a.m. because they sometimes have a packed house.

As the neighborhood hummed to life Wednesday morning, crews were still dousing an active flame with foam. Residents were checking out the damage and the rubble and glass that littered the streets was being swept up. Employees from one cafe damaged in the blast were pouring coffee for firefighters.

Seattle Fire Department spokeswoman Corey Orvold said residents of an apartment building and another nearby residential structure were evacuated after the blast.

There was no word of any other injuries or anyone missing, but Orvold said dogs were being used to go through the rubble just in case.

Andy Wappler, a spokesman for Puget Sound Energy, said the company shut down five of the six control valves that service the area where the explosion happened.

Harborview Medical Center spokeswoman Susan Gregg said eight firefighters and a battalion chief were treated at the facility.

She said five were treated and released early Wednesday and four others were in being discharged.

"We didn't have anybody with burns, nothing life-threatening, nothing major," said Gregg, adding that some firefighters were sent to the hospital to be checked out because the blast was so powerful it pushed them back.

Gregg said eight men and one woman were treated.

Contributing: The Associated Press.