PG&E detected gas before massive Hayward building explosion that injured 6 people: NTSB report

HAYWARD, Calif. (KGO) — New details about the massive gas explosion that injured six people and set off a major fire in a Hayward neighborhood were released on Thursday as part of a preliminary report from the National Transportation Safety Board.

The NTSB report states that PG&E “detected gas at the ground level near the accident home” after the original leak was supposedly capped, but despite that, crews began digging operations and less than an hour later the explosion occurred.

The report also revealed that PG&E crews knocked on the doors of the accident home and neighboring homes to make contact with the residents, but no one responded.

Three people inside that home were seriously injured by the explosion and taken to the hospital. The report revealed that the three additional injured people were PG&E employees.

MORE: Witnesses describe seeing victims walk out of home after Hayward explosion: ‘Blood all over’

Below is a minute-by-minute timeline of the December 11, 2025 incident as stated in the NTSB report:

• 7:25 a.m. PG&E notified by Mayo Asphalt Milling that a service line was damaged while they were doing roadwork on East Lewelling Boulevard




• 7:48 a.m. PG&E arrived on scene and found the leak at 868 East Lewelling Boulevard




• 7:51 a.m. Alameda County Fire Department arrives on scene but left shortly after when PG&E responder told them their assistance was not needed




• 8:18 a.m. PG&E crew squeezed off the service line where the damage had been done by the construction crew. Shortly after this, they detected gas at the ground level of the explosion site. PG&E crews said they knocked on the doors of the homes at the explosion site but no one answered.




• 8:40 a.m. PG&E crew began digging




• 9:29 a.m. PG&E crew squeezed off the gas main and stopped flow of gas in the main and service lines at the explosion site




• 9:37 a.m. The explosion occurs, demolishing one home and severely damaging several others. Alameda County Fire returns to the scene

The NTSB said this report is only preliminary and is subject to change as their investigation continues to unfold.

“Future investigative activity will focus on the physical evidence secured at the accident site, safe excavation practices, and PG&E’s leak response and leak investigation procedures,” the NTSB wrote in the report.

Dramatic footage captured from a home’s doorbell camera showed a large excavator being used to dig in front of the home, which exploded as a worker stood nearby.

Within moments, a massive explosion and flames blew out the walls and the roof of the home. People nearby appeared to be dazed for a few seconds, before running toward the home to search for any victims. Several workers lifted a large piece of debris from where it landed near the excavator.

“We were sitting in the house and it just — everything shook. Stuff fell off the walls, and when we looked at the camera, it was like you were watching a war video,” Brittany Maldonado, who provided the doorbell cam footage, told ABC7 News.

Two homes were impacted by the explosion and fire, and a workshop in the back of one of them. Another home has some damage on the side facing the explosion. The neighborhood is a mixed housing and business area right off Highway 238.

PG&E, Cal/OSHA and several other agencies have also launched investigations into the explosion.

Why weren’t residents immediately evacuated?

ABC7 News I-Team reporter Melanie Woodrow investigated why first responders didn’t evacuate people from the area upon arrival. She talked with Richard Meier, a fire and explosion investigator, about what the standard protocol is in situations like this.

“To me, it’s not reasonable; it’s understandable why (shutting off the gas) takes them so long, but I don’t think it is reasonable in that they could do a better job identifying the locations where their valves are, put them in more accessible places where they are easier to access,” Meier said.

Another big question: why didn’t PG&E or first responders evacuate the area?

“It is not something that we typically do; it is something that first responders usually do,” Sarkissian said.

But first responders pushed back on that.

“When our crews showed up two hours prior, we did not smell gas, detect gas, or see any reason for an emergency, so we waited to speak to PG&E, and PG&E said they could handle the situation, so our crews were released at that point,” said Alameda County Fire Deputy Chief Ryan Nishimoto.

“It is the responsibility of the gas company to evacuate people in the event of a known leak; they can’t just push that off onto the fire department. What if no one had called the fire department and they’re the only ones there?” Meier said.

The Associated Press contributed to this article.

Stay with ABC7 News for updates on this developing story.