Wearable device is disclosed to quickly deliver thermal treatment. port. A separate material or component is later added through a port at point of injury or a medical event. Wearable thermal device comprises: at least one containment pack of selected shape； containment pack(s) contains a selected amount of first material (preloaded component)； at least one port is attached to containment pack(s) configured to accept a second material (second component)； and said second material is added through said at least one port to create a chemical reaction when combined with said first material. In one embodiment, first material needed to create an endothermic reaction is a selected amount of ammonium nitrate contained within wearable hypothermic treating device. A port or valve is configured to accept water. When a selected amount ammonium nitrate is combined with water a selected amount of thermal mass is created.
