KANSAS CITY, Mo. (AP) -- Authorities were bringing in heavy equipment Wednesday to remove blackened rubble and aid their search for a missing employee of a popular Kansas City restaurant destroyed by a gas explosion and the ensuing inferno.
Seven people injured in the Wednesday evening explosion at JJ's restaurant remained hospitalized Wednesday, including two whose conditions were critical. At least seven others were treated and released.
One of two people first feared to be missing was later found receiving treatment at a hospital. But a woman who worked at JJ's and who was seen there before the blast was still missing, and Mayor Sly James stressed that finding her would remain the primary focus of Wednesday's efforts.
"Our main concern right now is the fact that we have a missing individual whose family is very much in anguish about that," James said Wednesday morning. "We need to resolve that problem. There is some hope in light of the fact that last night there were two people missing and we found one."
Fire Chief Paul Berardi declined to release any information about the missing woman except that she worked at JJ's.
The blast happened at 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.
Witnesses reported that there was a strong smell of gas in the area before the blast, and Missouri Gas Energy, which supplies the area, said in a statement that "early indications are that a contractor doing underground work struck a natural gas line."
Cadaver dogs searched the rubble Tuesday night but did not find anything, so heavy equipment was brought in at dawn to remove several feet of heavy debris, James said.
Workers were rushing to remove the debris and investigate the cause because a major winter storm was forecast to hit the area Wednesday evening, James said.
"We have a major storm coming in this evening," James said. "We're going to work diligently to get in (to the blast site) to get underneath that weather."
Berardi said firefighters were called about 5:15 p.m. with a report that a construction worker had hit a gas line near the restaurant. Firefighters conferred with MGE workers and left the scene, and the explosion occurred about 45 minutes later. He said the cause of the gas leak and fire is still unknown.
"Once we confirm the victim is or isn't inside the building, that part of the investigation will continue," Berardi said.
JJ's had managed — until Tuesday night — to survive in the shadow a large construction project that has been under way across the narrow, one-way street for seven years. The work had complicated access to the street-corner restaurant, and a server needed hospital treatment in 2006 after she was struck by a rock sent flying by blasting for excavation of the construction site.
It was not known whether the contractor said by MGE to have been doing underground work was connected to the construction project.
Dr. John Verstraete, who works at Plaza Physicians Group next door to JJ's, told The Kansas City Star that several employees of the office smelled gas for several hours Tuesday afternoon. The smell grew stronger through the day, and a gas company employee entered the medical office just before 6 p.m. recommending that it be evacuated, he said.
The blast shattered windows in some businesses at a small strip mall nearby, and residents of some neighboring apartments reported minor interior damage. One side of a brick apartment building that shares the block with JJ's appeared to have been scorched.
Jim Ligon, a JJ's bartender, said he wasn't working Tuesday night but started getting texts and calls from co-workers minutes after the explosion. He said the incident happened during the peak of weekday happy hour, when there is typically anywhere from 15 to 45 people in the bar area as well as three to five tables of diners at the restaurant.
"JJ's has a small staff, a family feel," said Ligon, 45, of Kansas City, Mo. "You see the same 100 people all the time — a bar and restaurant for regulars. We're just really hoping we come out of here OK in terms of injuries."
The restaurant consistently received high ratings from contributors to Zagat's restaurant guides, both for its food and its wine list of hundreds of selections.
The shopping area was established in 1922 by J.C. Nichols. Based on the architecture of Seville, Spain, it includes retail, restaurants, apartments and offices.
Associated Press reporters Heather Hollingsworth in Kansas City and Jeff McMurray in Chicago contributed to this report.