20:12 Hrs: Rescue 7 was requested by Chief 7 to report to 300 West First St. for a possible CO Alarm. During the initial investigation, Crews encountered a high reading of CO at the main entrance. While the building was being evacuated, Chief 7 requested the remainder of the Department as well as EMS to assist with the investigation. Interior crews reported the cause was from multiple gas stoves being utilized with no ventilation equipment. Personnel spent over one hour ventilating the building before returning to service.