Crews were trying to determine Sunday night whether a gas leak triggered the fiery blast that started with an explosion at about 5 a.m. in the 500-block of 7th Avenue.
The family who lives in the home that exploded was on vacation in California. One hundred thirty-six ComEd customers lost power.
Few were awake when the explosion rocked the entire neighborhood on the northeast side of Marengo, which is located about 60 miles northwest of Chicago.
"I just heard a really big boom and I saw my wall flex. My garage," said resident Dierkes Taylor.
"We woke up to our window pushing into our bedroom," said resident Jennifer Reher.
"We thought a car had hit the front of the house. It was a loud enough boom that all the pictures on the wall all fell down," said resident Kyle Alt.
The ball of fire was seen miles away, steadily growing as it spread to four other homes, taking vehicles along with it. Residents began to pour out onto the street and while they soon realized nobody was in the now-destroyed home others were in trouble.
"I didn't know what was going on. Just saw fire," said resident Jennifer Reher. "I heard Kim screaming down the street. There was a family trapped."
Neighbors were able to use a ladder to get the trapped family out of the house just before it collapsed under the weight of the spreading flames. The fire department made additional rescues when they arrived.
"They made several rescues out of the windows in the houses next door that were also on fire," said Chief Bob Bradbury, of the Marengo Fire Department.
Home damage ranged from blown-out windows to houses rocked off their foundation.
The American Red Cross was in the neighborhood immediately afterwards.
"We don't know when they're getting back in. We've got a dozen homes that are for sure uninhabitable and that list is growing," said Tony Blumberg, of the American Red Cross.
It was immediately unknown when residents from the immediate blast area would be able to return to their homes.