Authorities found an unspecified amount of potassium cyanide Thursday during a well-being check on the 2200 block of Wharf Drive in Woodridge, police said Friday.
The toxic substance prompted a response by hazardous material crews, which determined there was no danger and cleaned up the area. Nearby residents were evacuated from their homes from roughly 3:30 to 6:30 p.m.
No injuries were reported but police said one resident, who had taken the chemical from his employer, was taken to a hospital for evaluation. The case remained under investigation.