NTSB Probe Zeros in on Father-Son Team in Minnesota Gas Blast

Federal investigators said Friday they are looking into the oversight of a father-son team that was conducting the “hazardous operation” of moving a gas meter at a Minneapolis school when a natural gas explosion caused part of a building to collapse, killing two people.

The father and son were working for a contractor that was moving the meter from inside Minnehaha Academy to outside the school as part of gas company’s CenterPoint Energy’s plan to move meters outside for easier access, the National Transportation Safety Board said.

NTSB investigators were interviewing the father and son, who were working for contractor Master Mechanical, and planned to interview other employees and gas company workers as well, said Christopher Hart, an NTSB board member. He said investigators were seeking details about the relationship between the two companies, the process for contracts, and any oversight of the meter’s movement.

“That’s a very hazardous operation and requires considerable planning and oversight to conduct that operation safely … and we want to find out all we can about how robust was that oversight process,” he said.

The bodies of two longtime school workers – receptionist Ruth Berg, 47, and custodian John Carlson, 82 – were found in the rubble earlier this week. The medical examiner said Friday that both died from blunt force injuries sustained when part of a school building collapsed on them.

Hart said investigators will also look into whether the father or son attempting to move the meter were fatigued, distracted or impaired, which is standard in any investigation. He said he was unsure if other contractors or the gas company were on site at the time. The question of whether the gas was shut off at the street or at the building was also being examined.

A representative for Master Mechanical did not return a message Friday. CenterPoint Energy referred questions to the NTSB.

Hart said it will take some time for investigators to get into the building’s basement to examine the pipes because the building is structurally unsafe. Hart said he and an investigator used a firetruck’s ladder to get over the rubble and get a closer look at the destruction, but excavators need to begin the painstaking process of removing debris without destroying evidence before investigators can get inside.

A memorial service for Carlson, a part-time janitor known for giving students ice cream treats, is scheduled for Sunday at the school. Services for Berg, who was engaged to be married, haven’t been announced.

Minnehaha Academy is a private Christian school that serves students ranging from pre-kindergarten to 12th grade. The blast affected the “upper school,” which houses the high school. Administrators have delayed the start of that school by two weeks, to Sept. 5.