The detonation, which occurred while construction work was taking place on the gas supply, ripped Minnehaha Academy’s Upper School in half at around 10am. It destroyed the main stairwell area and a group of classrooms for grades 9-12.
A small number of children were in the gym and on the field at the time of the explosion, but local authorities said that none students were harmed. All of those reported missing or injured are adults, they said.
Minneapolis officials initially said that one person had died, according to KARE 11, but that claim was later retracted by local fire department.

Fires were seen at the site after the roof collapsed in the wake of the explosion, but they have since been put out.  Authorities say a ruptured gas main may have caused the detonation just seconds after the alarm was raised.

 A prayer circle was led by the school chaplain after the explosion

One person who was unaccounted for was found unharmed outside the building by firefighters. Around a dozen students were in the gym when the explosion occurred, but none were killed, officials said.

Officials at the school, which is located on 3100 West River Parkway, said that all of the students – some of whom were on the field at the time, and many of whom were in the gym – had been accounted for.
However, two people are still missing, according to Assistant Fire Chief Brian Tyner. He said that while rubble is being combed for the pair – both believed to be adults – they could also be ‘walking around out here’.
‘I’m not confident that they are in there,’ he told the Star Tribune. ‘Our hopes are that they are not in there.’
The unaccounted-for figure was originally three, but that was lowered to two after one of the people was found unharmed outside the building.
Nine people were hospitalized at Hennepin County Medical Center after the explosion, three of whom were in critical condition and one of whom was treated and released.
Four of the victims were said to be in serious condition, and two had ‘very minor trauma’ according to Dr Jim Miner, chief of emergency services at HCMC.
Miner said that the treatments were for fractures, cuts and bruises, not burns, and that ‘It could have been a lot worse.’ He added: ‘We were relieved, we were prepared for a lot more injuries. It was a terrible tragedy.’
There are no details about the condition of the other victims, other than they were not in critical condition.
Contractors were working on the building when the explosion occurred, fire department officials said.

Photo shows a section of the school building  roof and walls collapsed in the wake of the massive explosion. The  school took in some 825 students during the 2015-16 year

Three other people were rescued from the roof of the building by the fire officials. They were school employees, a father visiting the school at the time of the explosion said. It’s not clear why they were on the roof.
It’s believed that the gas leak may have been caused by a ruptured gas line. Part of the brick building collapsed after the explosion, authorities said.
Becca Virden, spokeswoman for CenterPoint Energy, said that the gas supply to the school had been cut off after the explosion and that ‘well-trained, experienced crews on site [are] coordinating with local emergency officials to secure the area.’
‘We will conduct an investigation to determine the cause,’ she added.
City of Minneapolis records obtained by the Star Tribune said Master Mechanical Inc, based around five miles away in Eagan, had obtained a permit for ‘gas piping and hooking up meter’ at the school.
The company had previously been fined $1,000 in 2010 for a violation related to a worker’s protection from falling and $600 in 2014 for paperwork violations regarding hazard communication and an employee’s right to know, paperwork said.
Jenny O’Brien, a spokeswoman for Minnesota OSHA, said neither were ‘huge penalties’.
The explosion only affected the Upper School, officials said; the Lower School is several miles away and is undamaged. All of the unaccounted-for people are believed to be adults.

A school gym coach said that the explosion came just seconds after the warning was raised. He said someone had smelled gas.A father in the school said there were two groups inside the building when the explosion occurred: A group in the counselor’s office having a meeting, and a group of about a dozen students in the gym, practicing basketball.
He said that his daughter went to the door when the alarm went off, but was blown back by the explosion. She was unharmed, he said.
The school’s director of advancement, Sarah Jacobson, said that staff and children were told to evacuate before the explosion, although she declined to give further details.
Sophomore student and cross-country runner Kylee Kassebaum was inside the building at the time of the explosion; she and the rest of her cross-country team were just about to get an early lunch.
Both of the school’s campuses reopen on August 23.

Fire crews are now conducting a search-and-rescue operation within the rubble to look for the missing people, although it’s not known whether they are actually trapped beneath it, the fire department said.

Flames continued to burn an hour after the explosion, likely fed by gas lines, but were ultimately extinguished. Firefighters kept their hoses on the smoldering ruins to ensure the flames did not reignite.

Fire and medical crews descended on the site after the explosion early Wednesday morning

‘Being briefed regularly by Chief Fruetel and Acting Chief Arradondo regarding the gas explosion and building collapse at Minnehaha Academy,’ mayor Betsy Hodges tweeted shortly after news broke. ‘City first responders are fully engaged.’
Those in the neighborhood said that the explosion rattled windows on nearby buildings. ‘It was just a really loud boom,’ one resident told KARE 11. ‘You felt it in your chest.’
Minnesota Governor Mark Dayton said in a statement that his office is in constant contact with the school.