The chlorine gas this morning that interrupted a hotel convention to celebrate furry animals may have been released intentionally, authorities in Illinois said.
Rosemont police have no suspects, but said the incident is being treated as a criminal matter that is under investigation.
Guests at the Hyatt Regency Hotel in Rosemont first reported symptoms of nausea and dizziness early this morning. Nineteen guests were taken to area hospitals for treatment.
Gottlieb Memorial in Melrose Park, Illinois, confirmed that it treated three adult patients for chemical inhalation. Advocate Lutheran General Hospital in Park Ridge also confirmed it received patients, but would not say how many.
The Rosemont Public Safety department responded and measured a high amount of chlorine gas in the air. Hotel guests were ordered to evacuate.
Among the guests were attendees of the Midwest FurFest, an annual convention to "come together to celebrate...art, literature and performance based around anthropomorphic animals," according to the convention's website.
Furry animal fans, dressed up as their favorite characters, formed a line outside the hotel, waiting to go back inside.
HAZMAT technicians found the source of the gas in the hotel's ninth-floor stairwell. The substance was identified as powdered chlorine. The technicians then collected, decontaminated and ventilated the area.
Guests were allowed to return to their rooms after the hotel was deemed safe and chlorine gas-free.