Safety board investigates school blast
MINNEAPOLIS — Investigators from the National Transportation Safety Board arrived at a Minneapolis school on Thursday to begin determining what caused an apparent natural-gas explosion that killed two people and injured at least nine others, including one critically.
The explosion at Minnehaha Academy caused part of a school building to collapse Wednesday. The bodies of longtime school receptionist Ruth Berg and custodian John Carlson were found in the rubble.
City fire officials said the collapse was caused by a gas explosion in a utility area. 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.
Safety board spokesman Eric Weiss said the federal agency is investigating because it has jurisdiction over gas pipelines. Experts said the investigation will take time and include interviewing witnesses, including employees from Master Mechanical Inc.
Three people remained hospitalized Thursday. Six other patients taken to the hospital after Wednesday’s blast have been released.