Chicago first responders to practice mass casualty drill at Willis Tower

If you see a massive amount of Chicago police, firefighters and other first responders downtown Saturday, don't be surprised. 

The Office of Emergency Management and Communications (OEMC) says there will be a Public Safety Active Threat/Mass Casualty Drill at Willis Tower on Wacker Drive from 5 p.m. until 10 p.m. 

Traffic should not be impacted during this exercise. 

The Chicago Fire Department will being leading the activity with Chicago Police Department and the OEMC. 

Chicago's first responders participate in simulated situations a few times each year to practice emergency preparedness. For more information visit