Baltimore City residents watched as rescue personnel investigated the Aug. 10 explosion. Photo credit: Sarah Y. Kim for WYPR.

The Aug. 10 explosion in Northwest Baltimore that killed two people, injured seven and reduced three rowhomes to rubble was due to a “large natural gas buildup” ignited by a stove, city officials said Tuesday morning.

“Based on the investigation and evidence, it appears as though a stove was turned on, which provided the ignition source” at 4232 Labyrinth Rd, Fire Chief Niles Ford said.

He said a licensed contractor did HVAC work at the address the day before the explosion, but investigators did not find proper permits for their work.

“We weren’t able to receive extensive particular information on all the repairs that were done,” Ford said. He declined to name the contractor.

Ford also said that investigators were able to identify four gas meters associated with the explosion. Baltimore Gas and Electric records showed a spike in natural gas levels in those meters between 1:30 a.m. and 2:00 a.m. the morning of the incident, which occurred at 9:54 a.m.

The response and subsequent investigation of the incident was a multi-agency effort; Baltimore City’s Special Operations Team, police department, crime lab, housing department and Office of Emergency Management were aided by the Baltimore County Fire Department, Howard County Fire and Rescue Canine Unit, the American Red Cross the State Fire Marshal’s Office and the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Read more at WYPR