Downtown Chicago had a tense few minutes Sunday afternoon when a fire in an exhaust system on the second floor of the Builders Building at 222 N. LaSalle St. sent smoke into nearby Lower Wacker Drive and set off alarms across multiple office high-rises. The blaze was reported around 3:50 p.m., and fire crews quickly ramped up their response, upgrading the alarm and staging medical units as a precaution. Authorities did not immediately report any injuries.
According to the Chicago Fire Department, the fire started inside an exhaust system on the building’s second floor, as reported by CBS Chicago. The department called a still-and-box alarm and activated an EMS Plan 1, moves that bring in additional firefighting and medical resources for potentially complex incidents in dense downtown areas.
The Builders Building, a 26-story office tower completed in 1926, is a Loop mainstay with offices and street-level retail at 222 N. LaSalle, just off Wacker Drive and tied into the network of lower-level streets and pedestrian tunnels beneath downtown, according to Commercial Property Executive.
What The Extra Alarms Really Signal
A still-and-box alarm pulls in more engines, trucks, and command officers beyond the standard first response, while an EMS Plan 1 typically brings about five ambulances and additional medical command staff to the scene, according to Firehouse. For large or high-occupancy buildings, that kind of escalation is routine. It is designed to quickly boost manpower and medical support, and to cut down the chances that firefighters will have to deal with secondary evacuations in nearby properties.
Smoke In Lower Wacker And A Chorus Of Alarms
The fire triggered alarms in several neighboring buildings, and initial reports noted smoke migrating into the Lower Wacker Drive pedestrian tunnel. That can make life harder for both first responders and anyone on foot, since visibility and access are already tricky in the lower-level maze under the Loop. Crews stayed on scene to secure the area, track down the precise source of the exhaust fire, and work with building staff as the wider downtown alarm system was checked and reset.
The fire department’s early update did not list any transports to hospitals, and officials had not released a cause as of the initial coverage. Investigators and building management are expected to continue their follow-up as the scene is fully cleared and a formal origin-and-cause review moves forward.
