All known residents at a Silver Spring apartment complex that exploded and caught fire on Thursday have been accounted for, Fire Chief Scott Goldstein announced at a press conference Friday morning. 

Officials are still working to confirm that there were no other visitors in the Friendly Garden Apartments at the time of the explosion, which injured 14 people. Goldstein said three people are seriously injured, while 11 others sustained minor to moderate injuries. In a press conference later Friday afternoon, Goldstein said one of those seriously injured is a child, but he did not have an age.

Montgomery County Fire and Rescue received a call of an explosion and fire at the apartment complex on Lyttonsville Road at around 10:30 a.m. Thursday, and crews were able to rescue several people from a four-story building before a significant part of it collapsed. A video from a nearby resident’s security camera captured the moment of the explosion.

WATCH: Video shows the moment an explosion and a fire erupted at an apartment complex in Silver Spring. https://t.co/E2ntqgJ3zz pic.twitter.com/NGILDQ8WwX

— NBC4 Washington (@nbcwashington) March 3, 2022

By late Thursday afternoon, five buildings in the complex, in addition to the one where the explosion took place, had been evacuated as crews worked to account for residents and identify any further structural issues. Three of the six buildings in the complex were deemed unsafe for occupancy, and residents were expected to be allowed back into the remaining three buildings later Thursday evening. But around 7 p.m., Goldstein said Pepco officials were notified that all six buildings remained without power, as the blast had damaged the complex’s transformer — leaving a total of around 225 residents displaced overnight.

Around 3 p.m. on Friday, Goldstein announced that three of the six buildings would be reopening and residents would be able to return to their homes by 8 p.m.

Throughout the day Friday, fire and rescue workers continued investigating the pile of debris — by hand. Goldstein said dogs trained to identify human remains have signaled alerts in one area of the pile, but nothing has been found yet.

“It is still possible and this is a three or four-day event, continuing from this point forward based upon the complexity involved and the issues of working safely,” Goldstein said.

Friday’s investigation found that a gas pipe was cut in the basement of the building that exploded and caught fire, according to Goldstein. Earlier Friday morning, he had shared that a property maintenance worker was in the building at the time of the blast, and was cooperating with officials. He said it’s possible that the worker may have cut the pipe, but crews are still working to identify the source of the blast.

“We don’t not have the ability to connect that it was a human error that caused the explosion,” Goldstein said. “We have a cut gas pipe in the basement, we’re still working theories.”

County Executive Marc Elrich said Friday that the apartment building last had a fire safety inspection on February 2, 2022 and its last building code inspection (which occurs tri-annually) in September 2021.

“If [the cause is] something structural or a defect, those are the things that the county or state have the ability to regulate,” Elrich said. “If it’s human error, that’s not something we can regulate…better training perhaps. We’re waiting to get [more] information to determine what we do next, to make sure things like this don’t happen again.”

In 2016, a massive fire resulting from a gas explosion killed seven people and injured more than 30 at an apartment complex in Silver Spring, about a 15 minute drive away from the Friendly Garden Apartments. The National Transportation Safety Board concluded that Washington Gas failed equipment caused the explosion.

A fundraiser set up to assist the residents displaced by the fire has raised $220,000 in less than 24 hours, Elrich said.