PLUM, Pa. (NewsNation) — The cause of the house explosion in western Pennsylvania that killed five people, including a child, on Saturday remains under investigation.

Just 20 miles east of Pittsburgh, the explosion in Plum destroyed three structures and damaged at least a dozen others. It occurred shortly before 10:30 a.m. Saturday at a home owned by Heather Oravitz, the town’s community development director, and her husband. 

“We heard the huge explosion and we were being thrown from our couch almost all the way to the kitchen with glass shattering everywhere,” neighbor Rafal Kolankowski said. “I thought somebody threw a grenade at our house and was shooting our windows out.”

The Allegheny County fire marshal’s office and other authorities are still investigating several possible causes of the explosion, including the possibility that a hot water tank could be responsible.

The fire marshal’s office said in a statement Monday that it was aware of the reported hot water tank issues the homeowners were having. The agency planned to investigate the cause of the blast, with the hot water tank issue in mind, “along with any and all other possibilities,” the statement said.

Authorities cautioned that determining the exact cause of the explosion could take months.

“Nothing is officially given to the people or our community, Rustic Ridge, where we live. It’s probably going to be investigated for a very long time,” Kolankowski said.

Oravitz was among the five who were killed in the explosion. Other victims included 57-year-old Plum Borough Manager Michael Thomas and neighbors 55-year-old Kevin Sebunia, 38-year-old Casey Clontz and his 12-year-old son Keegan.

Oravitz’s husband, Paul, suffered severe burns over most of his body and remained hospitalized Tuesday in critical condition. Two others injured in the blast were treated at a hospital and have since been released.

Neighbors said they are still trying to comprehend this tragedy while mourning the loss of their friends.

“We are a pretty close-knit community in the neighborhood where we’re at, so this is pretty devastating, to be honest with you,” Kolankowski said.

NewsNation spoke with a home inspector who offered some warning signs for homeowners to be aware of when it comes to their own hot water systems.

“If you have a leaky tank, that’s a big warning sign that something is going on,” Bruce Fisher with White Glove Inspections said. “Something should be done.  It could be the pressure release valve, it could be from the tank itself that is leaking at the bottom. It’s failed and something should be done.”

Fisher said there have unfortunately been cases similar to what happened in Plum before where something exploded.

The Associated Press contributed to this report.