11.—(1) The operator of a barge which is carrying 3,000 kilograms or more of one or more explosives shall ensure that it displays hazard warning panels which shall be arranged so as to be visible on each side of the barge and each such panel shall—
(a)be weather resistant and durably marked so as to comply with the provisions of Schedule 4 (which relates to the required form, colour, information and specification);
(b)be either rigid or fixed so as to be rigid;
(c)be marked on or securely attached to the barge in a substantially vertical plane, and if that means of attachment is by a frame, that frame shall carry no other hazard warning panel; and
(d)have its lower edge at least one metre above the deck or, if that is not reasonably practicable, as high above the deck as is reasonably practicable.
(2) Where one or more explosives have been carried and all compartments have been emptied and cleaned or purged so that any explosive or its vapour which remains is not sufficient to create a risk to the health or safety of any person, then the operator shall ensure that the hazard warning panels and labels are either—
(a)completely covered or completely removed; or
(b)in the case of hazard warning panels only, partly covered or partly removed so as to leave visible only the telephone number and the text referred to in paragraph 3(c) and (d) of Schedule 4 respectively.
(3) Where two or more explosives have been carried and the compartments which were carrying one of them have been emptied and cleaned or purged so that any of the explosive or its vapour which remains is not sufficient to create a risk to the health or safety of any person, then the operator shall ensure that—
(a)the labels referring to the explosive which has been removed are completely covered or completely removed; and
(b)the hazard warning panels are changed, if necessary, so as to comply with paragraph 3 of Schedule 4.