BRISTOL, Pa. (AP) — Construction crews and drones searched the rubble of a Pennsylvania nursing home Wednesday, a day after a powerful explosion killed at least two people, collapsed part of the building and left several residents unaccounted for.

Emergency responders from across the region had evacuated residents and dug through debris on Tuesday amid flames, smoke, and a strong smell of gas. Governor Josh Shapiro confirmed during a news briefing that a second explosion also occurred shortly after the initial blast.

The explosion at the 174-bed nursing home in Bristol Township, located about 20 miles northeast of Philadelphia, occurred shortly after a utility crew had responded to reports of a gas odor at the facility. Investigators are currently examining whether a gas leak caused the explosion, though officials stress that this finding is still preliminary.

According to town fire chief Kevin Dippolito, five individuals remain unaccounted for, but it’s possible they left the scene with family members. The first report of an explosion came in at around 2:15 p.m. Tuesday. Rescuers faced a chaotic scene, pulling people from stairwells and elevator shafts, and firefighters successfully rescued two individuals from a collapsed section of the building.

Witness Willie Tye shared that he heard a loud boom while watching a basketball game, prompting him to rush outside where he was met with flames and people fleeing the premises.

The local gas utility, PECO, disclosed that its crews were already in transit to investigate reported gas odors when the explosion transpired. While the utility shut off gas and electricity to protect first responders and bystanders, it remains unclear whether PECO’s equipment was involved in the explosion.

Musuline Watson, a certified nursing assistant at the facility, described staff reporting a gas smell over the previous weekend but not expecting a serious issue as there was no heat detected in the room. The nursing home recently became affiliated with Saber Healthcare Group, previously known as Silver Lake Healthcare Center. Saber characterized the event as devastating, stating that they had promptly reported the gas odor before the explosion.

State records indicate that the facility had been cited for multiple violations in its most recent inspection, including insufficient fire safety measures. Following the incident, inquiries are expected from the Pennsylvania Public Utility Commission, which is investigating potential causes of the explosion.

As rescue operations continue, the community remains alert and supportive, seeking to help those affected by this tragic event.