Loves Park Police Chief Chuck Lynde tells 23 News a package with a motorcycle battery exploded at the building on Monday.
Lynde says one worker has minor irritation after the explosion, but everyone in the building avoided significant injuries.
The building was evacuated as a precaution.
Several emergency crews have responded to the Loves Park Post Office on Windsor Road after a report of a possible package explosion.
The building, located at 1702 Windsor Road, is being evacuated. Police and ambulance are at the scene.
We will provide updates as more information as it becomes available.
Source: WIFR 23 Rockford