Excerpts from the ChicagoSunTimes.com:

At 6:20 a.m. on Wednesday (5/1/19), a passerby alerted the Lisle-Woodridge Fire District (LWFD) to a structure fire in the 5600 block of River Drive. Firefighters en route learned that three people might still have been inside. When they arrived at 6:24 a.m., they reported heavy fire in the single-family home.

A nearby off-duty LWFD firefighter heard the radio report and went to help. He entered the home and got all three people, who did not know the home was on fire, out of the house. They were all treated and released at the scene. Firefighters got the blaze under control in 20 minutes. 

No civilians or firefighters were injured, and the cause of the fire is still under investigation.