MINNEAPOLIS _ Minnehaha Academy senior Chimali Day was in the school counselor's office, her parents by her side, when the sudden warning came.
"Get out!" a staffer cried, breaking the Wednesday morning calm on the upper school campus. "There's a gas leak."
Day leapt for the door just as the center of the south Minneapolis private school building exploded, the blast knocking her to the floor. Her mother jumped on top of her, instinctively sheltering her child with her body. Then they scrambled through the back door of the counseling office while Day's father went looking for her classmates.
The teenager was among the students and staff who escaped the natural gas explosion that killed receptionist Ruth Berg, 47, and janitor John F. Carlson, 82, and injured nine other people, one critically. Fire officials said the two bodies were found near each other, both on the south side of the rubble.
In a synopsis of the explosion released Thursday, the Fire Department said that Berg and Carlson "were located in the collapsed portion of the structure."
The next phase _ the investigation into the blast's cause _ began Thursday. A rapid-response team from the National Transportation Safety Board (NTSB) was at the school Thursday morning to investigate the leak.
The agency's team, whose overall responsibilities include investigating transportation and pipeline accidents, said it planned to brief the news media Thursday afternoon. The NTSB does not announce causes of accidents while on the scene. Rather, the agency says, such determinations can take a year or more before being reached.
Staff and parents at the Christian school along the Mississippi River gathered together to grieve Wednesday night, even as they gave thanks that fall classes were not yet in session when the blast occurred.
"Tonight is an example of the kind of caring community we are," Minnehaha Academy President Donna M. Harris, who was injured in the explosion, said during the prayer service at the academy's lower and middle campus.
Seven hundred people packed the campus chapel for the emotional event, which featured hymn-singing, words of comfort, and many tears.
"We're going to get through it," Harris said. "We trust God. He is going to do phenomenal work."
The explosion rocked and set ablaze the upper school at 10:23 a.m., causing a partial collapse. After the fire was extinguished, an intensive operation began to find the missing. The first body, later identified as that of Berg, was found about 2 p.m., according to Fire Chief John Fruetel. The second, that of Carlson, was found at dusk.
As of Thursday morning, assistant boys soccer coach and athletic facilities crew member Bryan Duffey remained hospitalized in critical condition and two were in satisfactory condition at Hennepin County Medical Center (HCMC).
"This morning our prayers are with Minnehaha's facilities team member Bryan Duffey and his family," the school said in a statement released Thursday. "We pray for his healing and for the wisdom of the doctors and nurses caring for him at this time."
Six others treated at HCMC, including Harris, have been released.
Dr. Jim Miner, the hospital's chief of emergency services, described the injuries as fractures, cuts and head wounds. He said no one was treated for burns.
"It could have been a lot worse," he told reporters outside the hospital Wednesday afternoon. "We were relieved; we were prepared for a lot more injuries." Still, he added, "It was a terrible tragedy."
After staff from the Hennepin County medical examiner's office removed Carlson's body from the blast site late Wednesday, fire investigators declared an end to their recovery operation.
