The blast struck the Bristol Health & Rehab Center, also known as Silver Lake Nursing Home, in Bristol Township around 2 p.m. while crews from the local utility company PECO were investigating reports of a strong gas odour inside the building.

According to a PECO statement, workers had responded shortly after the initial odour was reported and were onsite when an explosion occurred. “While crews were on site, an explosion occurred at the facility. PECO crews shut off natural gas and electric service to the facility to ensure the safety of first responders and local residents,” the utility said, reports CBS58.

Bristol Township Fire Department Chief Kevin Dippolito said in a press briefing that five people were still missing amid the chaotic rescue effort. “We’re still in rescue mode. We have not transitioned into a recovery mode,” Dippolito said, indicating crews were combing through debris for survivors.

The explosion triggered a massive fire and caused significant structural damage, with parts of the building collapsing. Emergency responders, bystanders and nursing home staff worked to evacuate residents, many of whom are elderly and require assistance.

Governor Josh Shapiro said investigators are still working to determine the exact cause of the blast. Preliminary findings point to a possible gas leak, but officials stressed the investigation remains ongoing and no definitive cause has yet been confirmed.

The facility, which is certified for 174 beds, was reported to have smelled of gas in the days before the explosion, though residents and staff did not initially raise alarm. Authorities established a reunification center at a nearby high school for displaced family members and survivors.