(KANSAS CITY, Mo.) -- More than a dozen people were injured after a natural gas explosion ripped through a popular downtown restaurant in an upscale section of Kansas City, Mo.
Witnesses say the huge fireball, which engulfed an entire city block Tuesday night, could be seen for miles. The explosion destroyed JJ's restaurant and rattled windows blocks away.
"Everything shook, and you could feel it almost as much as you could hear it," one witness said. "It was by far the biggest explosion I've ever felt in my life."
There were no initial reports of fatalities, but cadaver dogs are searching the area. Kansas City Fire Chief Paul Berardi told reporters Wednesday morning that one person is missing.
"At this time we're still searching for one victim and that employee is a female employee of JJ's restaurant," he said.
St. Luke's Hospital said it treated eight patients, including two men who were in critical condition. Six other people had less serious injuries, according to ABC News affiliate KMBC-TV. The University of Kansas Hospital said it had received four patients and had a fifth on the way, KMBC reported.
More than 100 firefighters worked overnight to knock back the thick black smoke and shooting flames that forced onlookers to flee the downtown Kansas City shopping district just after 6 p.m.
"We are concerned that there may be additional people not able to get out of the structure," Berardi told reporters late Tuesday. "This was happy-hour at a restaurant. There were patrons in the restaurant."
"I would always fear there are fatalities in a scene like this," he added.
Investigators are sifting through the rubble Wednesday morning and trying to figure out what caused the blaze. It is believed that a contractor might have hit an underground natural gas line.
It almost smelled like the radiators were seeping out gas," one witness said. "Strong enough for us to call the landlord to say something was wrong."
Witnesses say gas fumes could still be smelled hours after firefighters got the flames under control.
Copyright 2013 ABC News Radio