A mailroom worker opening the day's correspondence at the Cook County Building found something alarming Thursday morning: an envelope addressed to Cook County Treasurer Maria Pappas containing a mysterious white powder. The discovery, made just after 10 a.m. on the first floor of Pappas's office at 118 N. Clark St., set off a chain reaction that brought hazmat crews, police and firefighters converging on the downtown Chicago building within minutes.
The worker put the envelope in a plastic bag as 911 was called. Pappas said the employee did not know what the substance was, which is why it was bagged rather than handled further. The Chicago Fire Department responded with a level-one hazmat operation, and as reported by abc7chicago.com, a hazmat crew, police and firefighters all arrived at the building within minutes of the envelope being found.
Pappas said her office was not evacuated and that she herself was not present when the envelope turned up, the station's report notes. The envelope appeared to have been mailed from the Carol Stream Post Office, based on its postmark, per the same account. Hazmat, fire and police teams worked to resolve the mystery quickly, and abc7chicago.com reported that authorities determined within about 45 minutes that the powder was baking powder. CBS Chicago separately reported that Pappas said the substance was determined to be baking soda and was not threatening.
Pappas Weighs In On Who May Be Behind It
Pappas offered her own theory on a possible sender, saying she believes a constituent angry about property taxes may have sent the envelope. She said she did not believe the incident was connected to a broader, nationwide investigation into suspicious letters sent to government offices, and that the sender probably intended to disrupt her office's operations and intimidate people or spread fear, according to CBS Chicago's reporting.
It wasn't immediately clear to responders whether the hazmat alert concerned Chicago's City Hall building or the separate Cook County Building, since the structure at 118 N. Clark Street houses multiple county government offices, including the treasurer's, the assessor's and the county board's. A broader nationwide investigation into similar mailings was underway, though its connection to the Chicago incidents had not been determined. The FBI declined to comment specifically on the letter sent to Pappas, per CBS Chicago, though the bureau said it was working with local law enforcement on several similar cases around the country to identify who is responsible for mailing the letters.
Second Scare Hits Nearby Elections Office
Hours later, emergency crews responded to another incident nearby at 69 W. Washington St., the address of Chicago's Board of Elections office, abc7chicago.com reported. The Chicago Fire Department's hazmat team was called to that building for a reported suspicious package shortly before 4 p.m., according to CBS Chicago. Police found no hazardous substance after inspecting the location.
Part Of A Wider Pattern Targeting Election Offices
The Cook County incident unfolded against the backdrop of a nationwide investigation into suspicious mailings sent to election and government offices. The FBI and U.S. Postal Inspection Service were investigating a series of such mailings sent to addresses across the country, some containing an unknown substance, according to votebeat.org. More than 100 letters were reportedly sent to people and groups nationwide, though the exact number directed at election officials specifically remains unknown, the outlet reported.
Officials in Louisiana and Oklahoma said they received suspicious letters containing a powdery white substance, votebeat.org reported, while the Wisconsin Elections Commission said a mail piece containing an unidentified powdery substance was examined and deemed not dangerous after a thorough review. Federal officials intercepted similar letters bound for the offices of the Ohio and New Hampshire secretaries of state, and Pennsylvania reported that the Postal Service blocked delivery of a suspicious letter before it arrived. Letters sent to Georgia, Idaho and South Dakota were also intercepted, per the same votebeat.org report.
In Ohio, the FBI opened its own investigation after the U.S. Postal Service intercepted a letter containing white powder intended for the secretary of state's office, according to cleveland19.com. That letter never reached its destination, as delivery was preempted by Postal Service investigators, the station reported. Separately, CNN reported that law enforcement agencies are investigating suspicious substances mailed to election offices nationwide as well as several congressional offices. Votebeat.org also noted that suspicious packages were sent to election officials in at least six states back in 2024, underscoring that this type of targeting is not new to election administrators.
