Police say an envelope that prompted the evacuation of a Janesville charter school posed no threat.
Investigators found no powder in the envelope as a person who opened the envelope had earlier reported.
Janesville police and firefighters were called Friday morning to a hazardous materials incident at Hewlett-Packard.
Police say the incident took place in a mail-processing area at Hewlett-Packard. Two workers who complained of irritation after being exposed to a powder were taken to a hospital along with three others who were in the room at the time.
Janesville Deputy Police Chief John Olsen says all indications are that the envelope was for normal business, The Janesville Gazette reports.
Students at the nearby TAGOS Academy were bused to another building as a precaution.