Firefighters battled a blaze Friday at a townhome in Darien.
Several departments responded to the fire at a home on the 7900 block of Knottingham Circle, which rendered the townhome uninhabitable.
At 1:52 p.m., the Darien-Woodridge Fire District responded to 911 reports.
When the first fire units arrived less than three minutes later, they found heavy smoke pouring from the roof of a four-unit townhome building.
Firefighters said initial reports from bystanders on the scene indicated there were people still in one of the units.
At that point, the fire was elevated to a box alarm level.
Crews entering the building were reporting heavy fire conditions on the second floor in two of the four units.
In the attempt to extinguish the blaze, firefighters made entry into attached units. Meanwhile, multiple hoselines were put in place to extinguish the fire.
After searching the four units, firefighters confirmed that the building was unoccupied.
Due to the spread of the fire throughout the walls and into the common attic space, extensive overhaul was necessary to put out the fire, according to firefighters.
Electricity, natural gas and water services to the entire building were shut off. That, along with the extent of the damage left all four units uninhabitable. Initial damage estimates are at $800,000, and the cause of the fire remains under investigation,
That investigation, however, will focus on plumbing work that was being completed in one of the units.
There was a minor injury reported by the Darien Police Department that a worker had suffered while inside the building. He was treated and released at the scene.
There were no casualties to firefighters, or anyone else as a result of the incident.
Darien-Woodridge received automatic aid for incident from Downers Grove, Westmont, Lisle-Woodridge, Lemont, LaGrange Park, Pleasantview, Tri-State, York Center, Argonne, Lombard and Romeoville Fire Departments.