Five months after an explosion leveled three rowhomes and killed two people in Baltimore, Fire Chief Niles R. Ford has provided a cause."The explosion was caused by a large natural gas buildup," Ford said at a Tuesday morning news conference.The Fire Department on Wednesday released its reportTwo people were killed -- Lonnie Herriott, 61, and Joseph Graham, 20 -- and seven people were injured after three rowhomes exploded on Labyrinth Road in northwest Baltimore in August.“Although five months have gone by, we continue to pray for recovery in this community,” Mayor Brandon Scott said. Ford said the explosion resulted from a buildup of natural gas and that on Aug. 9, the day before the explosion, unpermitted HVAC work was being done in the basement of 4232 Labyrinth Road. A buildup of natural gas formed, which was found to be spiked on four gas meters between 1:30 a.m. to 2 a.m. on Aug. 10."The readings revealed a spike in natural gas levels the morning of the explosion," Ford said.Ford said that on the morning of Aug. 10, a stove was lit, igniting the explosion.Ford clarified that the contractor was licensed, but no proper permits have been found for that address.In the Fire Department's report released Wednesday, fire officials said they're not ruling out that incomplete or improper installation caused the gas leak."It is never our goal to walk away from a scene with lives lost," Ford said. "Our goal is to help people and protect this community and I remain incredibly proud of the men and women of this department for their heroic efforts." Watch the full update on the explosion belowFire investigators have made contact with the landlord. Baltimore Gas and Electric released a statement Tuesday afternoon, saying: "As reported, BGE's equipment -- gas mains, gas service pipes, gas meters and electric equipment -- were operating safely and were not the cause of the natural gas explosion that occurred on Aug. 10."The investigation into the specific events leading to the explosion was conducted by the Baltimore City Fire Department which indicated today that work was being done on customer equipment by a licensed contractor in the basement of 4232 Labyrinth Road with no evidence of a Baltimore City permit."According to the Fire Department, a build-up of natural gas occurred and was ignited when a stove was turned on. Equipment beyond the meter -- including natural gas appliances -- are the responsibility of the customer. This incident is a very tragic reminder of the importance of natural gas safety. Our thoughts and prayers are with the families who lost loved ones and others affected by this incident. "Customers should ensure their gas appliances and piping are routinely inspected and properly maintained by licensed plumbers and appliance technicians and that they have the appropriate permits for the work. For more gas safety tips, go to bge.com/gassafety."As always, customers are reminded to call local emergency personnel at 911 from a safe location if they think they smell gas. Customers can contact BGE at 800-685-0123 from a safe location at any time, 365 days a year if they have any gas or electric safety concerns. BGE crews will respond promptly to assess the situation and work to make it safe."WBAL-TV 11 News spoke with northwest Baltimore residents who were relieved to have answers. “This is not easy. I think somebody should be held responsible for it,” said Monica Scovens, a northwest Baltimore resident said.“While it's good to have answers, it still puts people on edge,” said Arianne Burroughs, a northwest Baltimore resident.The grass covered area where three houses once stood is a troubling reminder of that horrific day.When asked about what goes through her head looking at the empty space, Burroughs said: “My neighbors still aren't home. That big open space. We don't know what the future holds for it.”“I believe the best thing for me is to move out. My daughter is in the first year of college. She doesn't sleep. We don't sleep,” Scovens said.Scott said the city is still working to help rebuild this shattered community.