A large fire tore through an apartment building in Upper Darby Township on Saturday, killing one person and sending several others to the hospital, according to township officials.

Upper Darby Township Mayor Ed Brown and Fire Chief Nick Martin said one resident died as a result of the fire, after being taken to the hospital. Seven people remained hospitalized as of Saturday evening, including one person in critical condition. One firefighter was also transported to the hospital and later released, officials said.

Fire crews responded to Llanerch Place Apartments, an apartment complex on the 3200 block of Township Line Road, just before 11 a.m. after reports of heavy smoke and a working fire. Chief Martin said the blaze originated on a lower floor, making rescues especially challenging as smoke and fire spread upward through the building.

“When the fire is anywhere below the top floor, you have all of the floors above,” Martin said. “In this case, you had people trapped on the second and third floors. Probably dozens of those people were rescued by firefighters.”

Firefighters used ground ladders, aerial ladders and hands-on interior rescues to evacuate residents from more than 20 apartment units involved in the fire, Martin said. Crews from Upper Darby Township were joined by firefighters from surrounding municipalities, as well as Delaware County emergency services.

Several residents escaped through windows with the help of firefighters. Among them was 7-year-old Faith Arnault, who she saw smoke fill the building.

“I couldn’t breathe when I saw the smoke — it was burning a lot,” Arnault said.

Arnault said firefighters held onto her as they helped her climb down from the building.

“They were holding me to help me climb down,” she said.

Others residents, like Darin Simon, were able to get out on their own.

“[I grabbed] my dog — that’s it,” Simon said. “Everything else can be replaced.”

Township officials said more than a dozen residents were displaced. A temporary shelter was established at Drexel Hill Middle School, where families received assistance and support throughout the day.

Arnault said she wanted firefighters to know how much their help meant to her.

“Thank you,” she said. “They were so helpful.”

Several units in the building were damaged, along with widespread smoke and water damage, which officials said will prevent some residents from returning home in the near future.

The cause of the fire remains under investigation.