Minnehaha Academy explosion NTSB report: Worker urged evacuations over radio

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The National Transportation Safety Board has released its preliminary report on the Aug. 2 gas explosion at Minnehaha Academy in Minneapolis. Two school staff members were killed in the explosion, and nine others were injured.

The explosion occurred at 10:22 a.m. at a building at Minnehaha Academy's Upper School. The school was on summer vacation at the time, but activities were still going on for a small number of students and staff. 

“At the time of the explosion, two workers were installing new piping to support the relocation of gas meters from the basement of the building to the outside,” the NTSB reported in its preliminary investigation. “ Two new meters mounted on a wall were ready for the new piping to be connected. While workers were removing the existing piping, a full-flow natural gas line at pressure was opened. The workers were unable to mitigate the release of the gas, so they evacuated the area.”

The NTSB report refers to a school maintenance worker using a handheld radio moments before the explosion. The report does not say whether or not the radio contributed to the explosion.

“A school maintenance worker heard and smelled the natural gas release and went to its source in the basement meter room where the workers had been,” the report said. “As he exited the basement, he made an announcement over his hand-held radio that there was gas in the building and to evacuate immediately. As he made his radio announcement, he ran up the stairs and searched for occupants. Less than one minute later, the building exploded.”

Longtime receptionist Ruth Berg and custodian John Carlson died in the explosion.

Minnehaha Academy is in the process of finalizing a lease for a temporary site for its Upper School. A source told Fox 9, Brown College in Mendota Heights will be the Upper School's temporary home school for the 2017-2018 school year. School leaders are planning to use pods for administrative staff offices, but not as classrooms.