School explosion probe focusing on pipeline; NTSB investigating blast that killed 2 in Minneapolis

Published 8:44 am Friday, August 4, 2017

MINNEAPOLIS  — Investigators from the National Transportation Safety Board arrived at a Minneapolis school on Thursday to begin the painstaking task of 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 natural 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.

Email newsletter signup

NTSB 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.

The company was issued a permit on June 7 for “gas piping and hooking up meter” at the school, according to city records. The permit did not include details on the type of work involved. Master Mechanical said in a statement that its employees were among the injured.

Mark Farley, a Houston-based attorney who specializes in major accident response, said investigators are going to be honing in on the cause of the blast. He said that includes examining physical evidence and interviewing potential witnesses.

Questions will include what type of work was being done, whether the building should have been occupied at the time, if all precautions were taken to make sure it was done safely, and whether the contractors should have isolated the natural gas source before proceeding, Farley said.

“The investigators at this point are going to try to determine what the root cause of the incident was,” he said.

He said at this point, it’s premature to say whether the building should have been cleared beforehand.