A private college prep school in Minneapolis is mourning two employees after an explosion and partial building collapse Wednesday. Officials say receptionist Ruth Berg, 47, and janitor John Carlson, 82, were killed in the natural gas explosion at the upper campus of Minnehaha Academy, the Star Tribune reports. Nine other people were injured, one critically, authorities say, though the blast would have been far more catastrophic, with hundreds potentially killed or injured, if fall classes had been in session. Girls taking part in a summer cross-country run practice left the building just 30 seconds before the blast. Fire officials say the explosion happened in a boiler room, though it's not clear what triggered it.
Carlson's wife tells Minnesota Public Radio that he graduated from the academy in 1953, sent his own children there, and returned to work there part-time after retiring 14 years ago. She says he wasn't scheduled to have been there at the time of the blast, but he went to work early because he had a doctor's appointment later Wednesday. Berg had worked at the academy for 17 years. "As our receptionist, she welcomed everyone with a smile and was always willing to go the extra mile to help our students, families, and staff," the school said in a statement. "She will be greatly missed." The staff members were mourned at a prayer service Wednesday evening.