Baltimore City

Deadly explosion in Northwest Baltimore was caused by gas buildup after HVAC work in a home, officials say

The August explosion that leveled rowhomes in a Northwest Baltimore neighborhood, killing two, was caused by a large natural gas buildup the day after a contractor worked on an HVAC system in one of the homes, city officials said Tuesday.

The morning of Aug. 10, someone turned on their stove, igniting the blast, Baltimore City Fire Chief Niles Ford said at a news conference.


The contractor was licensed, but the city has not located a permit for the HVAC work that took place at 4232 Labyrinth Road, Ford said. Officials did not identify the contractor.

“A spike in natural gas levels were detected between 1:30 and 2:00 in the morning of Aug. 10 from address 4232 Labyrinth Road,” Ford said.


Lonnie Herriott, a 61-year-old who was staying at that house at the time of the explosion, was killed. The massive blast also killed 20-year-old Morgan State University student Joseph Graham, and injured seven others. It leveled three two-story rowhomes and displaced dozens of residents in the Reisterstown Station neighborhood.

The Fire Department released a redacted report on the investigation into the explosion late Tuesday.

“It can’t be ruled out that improper or incomplete installation of the new HVAC system was the cause for the gas leak,” the report said. “It also can’t be ruled out that unknown person/s tampered with the gas piping the night before the explosion causing the gas leak.”

Typically, when the city’s Department of Housing and Community Development learns that work is being completed on a home without the proper permits, they file a “stop work” order with the property owner, said city spokeswoman Stefanie Mavronis. After that, the department could issue a fine, she said.

In this case, the department was awaiting the conclusion of investigations into the explosion before deciding whether to issue any penalties for the unpermitted work.

As part of the investigation, the fire department was able to reach the landlord who owned the three homes leveled in the explosion, Ford said.

Property records show that Leroy and Robin Johnson of Owings Mills own the homes, plus a fourth adjacent home that was condemned. They could not be reached for comment Tuesday.

The house at 4232 Labyrinth Road was not properly licensed for renters, Mavronis said, a requirement as of January 2019. The owners had started the licensing process but hadn’t finished it. It was, however, inspected as a rental in April 2019, and it passed.


The other three impacted properties were properly licensed for renters, Mavronis said.

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Leon Phillips, who lived at 4232 Labyrinth Road, told The Baltimore Sun in August that he smelled “a little bit of gas” when he woke up the morning of the explosion to head to work. He would’ve reported it, he said, but he stopped noticing the smell as he moved around the house.

“I wasn’t smelling much of it,” he said in an interview. “It wasn’t strong at all.”

Phillips confirmed that maintenance work was done on the home the day before the blast.

Shortly after the explosion, Baltimore Gas & Electric said it wasn’t to blame. Its gas mains, gas service pipes and gas meters were all functioning properly that day. Instead, it was likely customer-owned equipment — like gas pipes or appliances — that caused the disaster, the gas company said.

Mayor Brandon Scott, who grew up in Northwest Baltimore, said his mother called him on the day of the blast to tell him she had felt the ground shake at the nearby Giant supermarket where she works.


He thanked the neighbors and firefighters who rescued people trapped in the debris, as well as volunteers from across the city who donated food, clothing and other items in the aftermath.

“Rather than filming or standing on the sidelines, we saw neighbors in this community step up and work to save their neighbors who were trapped,” the mayor said. “Although five months have gone by, we continue to pray for the recovery in this community, and will continue to aid and encourage the healing process after this tragedy.”