Before loading, these by-products shall be cooled to ambient temperature, unless they have been calcined to remove moisture. Wagons and containers containing bulk loads shall be adequately ventilated and protected against ingress of water throughout the journey. The cargo doors of the closed wagons and closed containers shall be marked with the following in letters not less than 25 mm high:

                  "WARNING
   CLOSED MEANS OF CONTAINMENT
               OPEN WITH CAUTION"

This shall be in a language considered appropriate by the consignor.