4.—(1) Every ship carrying in bulk noxious liquid substances or unassessed liquid substances shall comply with the provisions of Schedule 1 of Merchant Shipping Notice NLS No 1.
(2) Except as provided for in paragraph (3)(b) and (c) chemical tankers constructed before 1st July 1986 shall be constructed, fitted, equipped, arranged and operated in accordance with those requirements of the BCH Code relevant to it.
(3) Every ship specified in subparagraphs (a), (b) or (c) shall be constructed, equipped and operated in accordance with those requirements of the IBC Code relevant to it—
(a)chemical tankers constructed on or after 1st July 1986;
(b)ships converted to being chemical tankers on or after that date except oil tankers—
(i)which were built before that date;
(ii)which are converted for the purpose of carrying pollution hazard substances only;
(iii)the conversion of which consists only of modifications necessary for compliance with Chapter VA of the BCH Code; and
(c)(to the extent that the Secretary of State considers reasonable and practicable) chemical tankers which were constructed before 1st July 1986, but undergo repairs, alterations and modifications of a major character on or after, that date.
(4) Where a chemical tanker is constructed or adapted to carry substances listed in Chapter 19 of the IGC Code (whether or not such substances are listed in Chapter 17 of the IBC Code) then, to the extent that the requirements of the IBC and IGC Codes are inconsistent, the requirements of the IGC Code shall prevail.
(5) In every chemical tanker constructed on or after 1st July 1986 the pumping and piping arrangements serving any tank designated for the carriage of a Category B substance or a Category C substance shall be such that they comply with Schedule 1 in Merchant Shipping Notice No NLS 1.