47.All cargo containers shall be designed and made for safe transportation. In addition,
(1) in the case of a top-loading metal cargo container, it shall have continuously welded joints and an impermeable bottom;
(2) in the case of a side-loading cargo container used to store receptacles of liquid materials, it shall have an impermeable basin able to contain 25% of the total capacity of all the stored receptacles; and
(3) in the case of a top-loading, side-unloading cargo container used to store bulk materials, it shall be equipped with a leakproof side opening able to retain the materials.