The present invention generally relates to an RFID inventory and expiration date tag for an in-cabin airline metal chemical oxygen generator canister or other in-cabin assets (such as canisters) and a method of using the same. The tag is especially suitable for use in connection with metal oxygen or other gaseous metal canisters used in the aerospace industry. The RFID tag allows for the rapid, efficient, accurate, frequent and easy monitoring of the expiration date of the oxygen generator. The tag has a plurality of stacked layers including layers of polypropylene, polyester, UHF Inlay, fire retardant polypropylene and an acrylic adhesive. The tag extends directly outward from the generator at a tangent to approximately a ninety degree angle with respect to the generator.