Tyler Smart was asleep in his mom's northwest suburban basement with his girlfriend early Sunday when he heard the boom.
"I jumped out of my bed, ran upstairs, looked over and I see these flames," Smart told reporters at the scene of the explosion in the 500 block of Seventh Avenue in Marengo.
"I went downstairs, grabbed my shirt, grabbed my shoes and came out here," Smart said.
The Marengo Fire Protection District responded at 4:50 a.m. to the report of an explosion and house fire, according to a statement posted on the city's website.
Smart assisted an elderly lady and her grandchildren. Only one person was hospitalized after the explosion.
"It's just a natural instinct for me to do that, to make sure everything is okay," Smart said.
Two homes were leveled, Marengo Fire Chief Bob Bradbury told reporters at the scene.
More than 45 homes were impacted by the explosion, and at least 14 were directly affected, according to a statement from the American Red Cross, which is providing immediate disaster relief for the families affected.
The Illinois State Fire Marshal is at the scene and has begun investigating, according to the city's statement.
Displaced residents are advised to go to Marengo High School at 110 Franks Rd. The school is additionally being used as a cooling station, and pets are welcome.
"Houses are replaceable. Everything's replaceable. Lives aren't," Smart said.