The system of the invention includes a method for monitoring changes in the status or condition of a Container using one or more monitoring units mounted to the Container. The monitoring units preferably include a power supply, sensors using reflective energy with programmable parameters, globally-unique sensor identification, recording capability on a timeline, long term memory and the ability to rebroadcast information on RFID radio technology. Programmable monitoring hardware in the monitoring unit detects significant changes in the sensor outputs as a triggering event. The programmable monitoring hardware includes memory for storing identification information for the Container. The sensors which can include conventional devices that detect various forms of energy including visible light, infrared light, magnetic fields, radio frequency energy and sound. In one embodiment, a monitoring unit is mounted inside a shipping Container suitable for long distance transport. The triggering event can be used for tamper detection security.