KANSAS CITY, Mo. (AP) — A day after a natural gas explosion leveled a popular restaurant, investigators raced to search the rubble and tried to understand how the blast happened despite suspicions that flammable fuel had been leaking, maybe for weeks, somewhere in the busy outdoor shopping area.
Hours before the explosion, witnesses reported a strong smell of gas, and firefighters were summoned to the scene at one point but left without ordering an evacuation.
As the cleanup got under way Wednesday, search-and-rescue crews recovered a body, and the mayor worried that the debris could be concealing other victims.
Mayor Sly James declined to say whether the body was that of a man or a woman, though authorities had been looking for a missing woman who worked at JJ's restaurant and had been seen there before the Tuesday evening blast. They previously said she was the only person still unaccounted for.
But James said at a news conference that authorities could not be "100 percent sure" they had accounted "for every single person that may have been at JJ's when the explosion occurred." The search started without a list of people who were in the building.
Crews using flashlights, cadaver dogs and heavy equipment rushed to finish the search ahead of a winter storm that was expected to bring heavy snow.
The explosion occurred after a construction crew apparently struck a natural gas line, touching off a blast that could be felt for nearly a mile.
Surveillance video from a nearby travel agency shows a fireball erupting from the restaurant's roof, showering the street with debris and throwing up a cloud of dust and smoke. The blast shattered glass in neighboring buildings.
Fifteen people were injured. Six were still hospitalized Wednesday, James said.
People who live and work in the area reported smelling gas for some time.
Jeff Rogers was waiting at a bus stop down the street from JJ's when the explosion knocked him and another man to the ground.
He said he had smelled gas — although "not strong" — at the intersection for the past couple of weeks. Then the odor intensified Tuesday.
William Borregard, who lives with his sister and her fiancé in the apartment building nearest to JJ's, said he had noticed a strange smell for weeks that had worsened in recent days. On Tuesday, they called the apartment manager.
"We said it's very pungent, and you should come out here and check it out," he said. "He came over and rapped on the door and said there's nothing to worry about. Stay in your apartment. That was five minutes prior to the explosion."
Dr. John Verstraete, a physician who works at a medical practice next to the restaurant, told The Kansas City Star that some office employees smelled gas for several hours Tuesday afternoon. The smell grew stronger through the day.
A gas company employee entered the building just before 6 p.m. and recommended evacuating.
The blast happened around 6 p.m. Tuesday, when the dinner crowd would have been filing into JJ's and the many other restaurants in the upscale Country Club Plaza shopping and dining district.
The restaurant was a fixture on the city's culinary scene for more than 27 years. Locals knew it as a prime after-work stop, though it won a broader reputation after receiving consistently high ratings from contributors to Zagat's restaurant guides, both for its food and its long wine list.
Firefighters received a call about 5:15 p.m. that a construction worker had hit a gas line near the restaurant, and they conferred with employees of Missouri Gas Energy, which supplies the area.
It wasn't clear Wednesday how hard firefighters or utility officials worked to evacuate the restaurant after gas was first noticed. Fire Chief Paul Berardi said the fire department deferred to the utility since it would have more expertise in assessing the seriousness of the situation.
Richard Kuprewicz, a pipeline safety consultant in Redmond, Wash., said federal law holds the utility responsible for deciding whether to evacuate, but assessing the risk isn't always easy.
Sometimes it's difficult to determine how much gas has been built up. And even highly trained people can underestimate the danger.
"I've seen people who work for gas companies and have gas sniffers, and their bodies are found in buildings," Kuprewicz said. "There is some art and some experience and some training in this stuff."
The fire chief said the precise cause of the gas leak is still under investigation.
A construction project had been going on across a narrow, one-way street from JJ's for seven years. But it was not clear Wednesday whether that work was connected to the contractor that MGE said had been underground.
MGE planned to issue a statement later Wednesday.
The Missouri Public Service Commission, which oversees utilities, launched an investigation into the blast, dispatching five employees to the site.
Commission Chairman Kevin Gunn said preliminary information indicates that gas pipelines had been marked as required.
Investigators will look at whether MGE followed state rules in responding to the gas leak reported beforehand. It could take up to six months before a final report is issued.
Rebecca Craven, program director for the Pipeline Safety Trust in Bellingham, Wash., said natural gas explosions are "ridiculously common," with 37 percent of the most serious incidents caused by digging damage.
"Distribution lines are everywhere in every big city," Craven said. "They get dinged by construction folks or people putting in a new mailbox all the time."