NTSB investigates blast that killed 2 at Minneapolis school

MINNEAPOLIS -- Investigators from the National Transportation Safety Board were sent to a Minneapolis school Thursday to look into an apparent natural-gas explosion and partial building collapse that killed two people and injured at least nine, including one critically.

The explosion at Minnehaha Academy reduced part of a building on its upper-school campus to rubble. City fire officials said Wednesday's collapse was caused by a natural-gas explosion. Contractors were working in the school at the time, and some witnesses said they were warned of a gas leak moments before the blast.

Some first responders also reported smelling natural gas as they pulled people to safety.

The blast occurred in a utility area as students were playing soccer and basketball at school, according to fire and school officials. NTSB spokesman Eric Weiss said the agency is investigating because it has jurisdiction over gas pipelines.

Minneapolis fire chief John Fruetel said two bodies were pulled from the rubble Wednesday. While officials have not identified them formally, Minnehaha Academy said on its Facebook page the victims were Ruth Berg, a receptionist for 17 years at the school who "welcomed everyone with a smile," and John Carlson, a part-time janitor known for giving Dilly Bars to students.

Carlson, 81, attended the school as a child, sent his own children there and was a grandfather figure to students, school officials said.

Three people remained hospitalized Thursday, including one in critical condition, according to Hennepin County Medical Center.

Six other patients who were brought to the hospital after Wednesday's blast have been released.

Dr. Jim Miner, the hospital's chief of emergency medicine, said victims suffered injuries ranging from head injuries and broken bones to cuts from debris.

Minnehaha Academy is a private, Christian school that serves students from pre-kindergarten through 12th grades.

The explosion affected only the upper school; the lower and middle school campus is about a mile and a half away.

Aerial video footage of the school's campus showed part of a building was ripped apart, with wood splintered and bricks scattered about. Windows in other areas were blown out and shattered.

Three people were rescued from the building's roof shortly after the explosion and fire, Tyner said.

The Star Tribune reported city records show Master Mechanical Inc. was issued a permit June 7 for "gas piping and hooking up meter" at the school's address.

Master Mechanical said in a statement Thursday its employees were among the injured. The contractor did not say how many of its employees were hurt.

Master Mechanical has been cited twice for workplace violations in recent years, according to the newspaper.

Jenny O'Brien, a spokeswoman for the Minnesota Occupational Safety and Health Administration, said in 2010 there was a violation related to protecting an employee from falling. In 2014, the company had paperwork violations.