Data is stored on a tag unit. The tag unit provides for alert monitoring capabilities and monitoring of events, these capabilities allow for supply chain plans to be restructured and for events to be rescheduled. The tag unit is attached to an item for tracking purposes. The tag unit monitors and stores a status of the item. Then the item is sent to a destination. The tag unit is scanned when the item has been sent to a destination. The data on the tag unit is updated as a function of scanning. The data is updated when the tag unit is scanned at a destination. Then the data on the tag unit is validated. The data is validated for security purposes. The data on the tag unit is scanned to identify conditions to trigger actions. The system recovers from failure to read data on the tag unit by reconstructing the expected data from a history of the tag unit. Failure may be a result of identified or unidentified tempering of tag units, failure of the tag unit mechanism, or violation of the tag unit access limitations.