Investigators spent much of the weekend sifting through debris scattered across the yard of a house that was leveled in an explosion Friday.

Plenty of questions lingered Monday.

Firefighters from Jacksonville and South Jacksonville responded about 4:50 p.m. Friday to the 2100 block of East Morton Avenue near Blacks Lane.

Witnesses reported hearing a loud boom but said there was no indication of a problem beforehand.

The blast was so intense it send sheets of insulation into the branches of nearby trees.

Two people living in the house were trapped in the rubble; they were taken to Jacksonville Memorial Hospital and then transferred to a trauma center in Springfield, according to Morgan County Emergency Management Director Phil McCarty. They remained hospitalized Monday, he said.

At least one dog also was rescued from the scene.

Jacksonville Fire Department is working with Ameren Illinois, the Office of the Illinois State Fire Marshal, Illinois Commerce
Commission and Morgan County Sheriff’s Department to determine the cause of the explosion.

“When we cleared from the scene, the state fire marshal arson investigator, ICC and Ameren were still there,” Jacksonville Fire Department Capt. Curt Rueter said Monday.

State offices were closed Monday for Columbus Day and representatives of the Office of the Illinois State Fire Marshal and Illinois Commerce Commission, which “oversees the provision of adequate, reliable, efficient and safe utility services” in the state, according to its website, were unavailable for comment.

An Ameren Illinois spokesperson said the incident is being investigated locally and Ameren had no information about a cause or where the investigation stood.

The house, reduced to a pile of rubble barely recognizable as ever having been a structure — except for a portion of roof that remained intact — was a total loss, Rueter confirmed. The home was valued at $120,000.

Despite the destruction, there was little to no fire involved.

“There was no fire or smoke when we arrived,” Rueter said. “I believe there was dust in the air, but no signs of a fire.”

The lack of fire was unusual for such an explosion, McCarty said.

He did not expect to have answers about the cause of the blast for weeks, if not months, he said.