18.—(1) Subject to paragraph (2), no operator of a container, or tank vehicle shall cause or permit to be carried therein any dangerous goods which are required by the CDGCPL Regulations to be labelled with a “liable to explosion” subsidiary hazard sign together with any other dangerous goods unless effective measures have been taken to ensure that the carriage of such a mixed load is no more dangerous than the carriage of the same total quantity of dangerous goods in an unmixed load.
(2) The prohibition referred to in paragraph (1) shall not apply to any mixed load of dangerous goods where the load is mixed only to the extent that each of the dangerous goods is carried in separate, closed containers with complete sides.