The Fire Department uses the Certificate of Occupancy (C.O.) information to help identify potential hazards that may be encountered while responding to emergency calls. The Post Office requires a current C.O. with the correct address before mail will be delivered. When the building is new, the C.O. verifies that it conforms to the most current life safety standards. When the building is existing, has an ownership change, tenant change, or change in how the building is used, a new C.O. is required to provide that the building is still safe to occupy.