BEDFORD PARK, Ill. (AP) -- The busiest day of a national bioterrorism drill began Thursday with a building collapse and is scripted to end in triumph, with a raid on the fictional group responsible for a week of chaos.
State, local and federal officials in the Chicago area scrambled to deal with two mock catastrophes Thursday morning: the collapsed building and the release of a chemical at a chemical plant in suburban Bedford Park.
The incidents were reported one after the other around 9 a.m. According to the disaster script, rescuers responding to a building explosion believed 26 people were trapped and that another 20 about a mile away were in danger from the chemical release.
Dozens of fire trucks, ambulances and special teams trailers streamed into the site of the mock building collapse, which was complete with a very real pile of rubble.
As cranes dug through the debris, three helicopters buzzed overhead.
By afternoon, authorities said, 600 firefighters and emergency workers would be on the scene. Sometime in the afternoon, authorities planned to announce whether terrorism was to blame for the fictional disaster.
The rescuers' response will reveal to first responders the strengths and weaknesses of the system, authorities said.
``We're going to push the statewide plan to the limit and try to break it,'' said Jay Reardon, president of the Illinois Mutual Aid Box Alarm system. ``And if we can break it, then we know what we've got to fix.''
Homeland Security Secretary Tom Ridge planned a tour of Chicago's emergency operations center later in the day as the five-day drill winds down.
It began Monday in Seattle with the simulated detonation of a radioactive ``dirty bomb.'' In the script, a fictitious plague had been sprayed across Chicago but hadn't yet been detected. Volunteer patients began streaming into hospitals on Tuesday and were clamoring for antibiotics by Thursday.
The drill, headed by the Homeland Security Department at an estimated cost of $16 million, is meant to test the nation's readiness to deal with simultaneous terrorist attacks. More than 8,500 people from 100 federal, state and local agencies, the Red Cross and the Canadian government are participating.
While cities were warned that they would be targets of the drill, some details were kept secret to make the exercise more realistic.
Thursday's scheduled events included a mock plane crash in the early evening at Midway Airport. City officials warned residents around the airport of planned street closings and were posting signs at the airport about the drill, expected to generate billows of smoke and bring several emergency vehicles to the scene.
The drill was scripted to end with a raid on a secret biological lab in Chicago run by the fictional terrorist group responsible for both the plague and the Seattle bomb.