The nearly nine-hour closure of a stretch of the Eisenhower Expressway on Thursday was caused by an explosion that left a person dead, federal authorities confirmed Friday.
Just after 10 a.m., Illinois state troopers came onto an “active incident” on the westbound Interstate 290 between Mannheim Road and the Tri-State Tollway (Interstate 294), state police said in a statement.
Authorities shut down all lanes of the expressway as multiple law enforcement agencies, including the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives, assisted on the scene.
A coordinated investigation led by federal authorities determined the incident was an explosion that resulted in the death of one person, ATF said in a statement Friday afternoon. Federal officials said they found no evidence that the incident was connected to any other event or that any other individuals were involved.
In the wake of the incident, the Cook County medical examiner’s office confirmed the death of a male of unknown age on the roadway just west of 25th Avenue in Hillside but provided no other details.
The person’s identity and cause of death had not been publicly released as of Friday afternoon.
“We recognize the significant public interest generated by the law enforcement response and roadway closures,” the ATF stated Friday. Authorities had released scant information about the incident throughout the day on Thursday as the Eisenhower remained closed for hours.
“The involvement of highly specialized federal, state, and local resources was necessary to safely process the scene and ensure public safety,” the ATF continued.
The expressway was finally reopened just before 7 p.m. Thursday.
The ATF said additional details will be released “as appropriate.”
The Tribune’s William Lee contributed.
