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to either marine resources or human health or cause serious harm to amenities 
or other legitimate uses of the sea and therefore justify the application of 
stringent anti-pollution measures. 
(bv) Category B—Noxious liquid substances which if discharged into the sea 
from tank cleaning or deballasting operations would present a hazard to either 
marine resources or human health or cause harm to amenities or other legitimate 
uses of the sea and therefore justify the application of special anti-pollution 
measures. 
(c) Category C—Noxious liquid substances which if discharged into the sea 
from tank cleaning or deballasting operations would present a minor hazard to 
either marine resources or human health or cause minor harm to amenities or 
other legitimate uses of the sea and therefore require special operational 
conditions. 
(d) Category D—Noxious liquid substances which if discharged into the sea 
from tank cleaning or deballasting operations would present a recognizable 
hazard to either marine resources or human health or cause minimal harm 
to amenities or other legitimate uses of the sea and therefore require some at- 
tention in operational conditions. 
(2) Guidelines for use in the categorization of noxious liquid substances are 
given in Appendix I to this Annex. 
(3) The list of noxious liquid substances carried in bulk and presently cate- 
gorized which are subject to the provisions of this Annex is set out in Appen- 
dix II to this Annex. 
(4) Where it is proposed to carry a liquid substance in bulk which has not 
been categorized under paragraph (1) of this Regulation or evaluated as re- 
ferred to in Regulation 4(1) of this Annex, the Governments of Parties to the 
Convention involved in the proposed operation shall establish and agree on a 
provisional assessment for the proposed operation on the basis of the guidelines 
referred to in paragraph (2) of this Regulation. Until full agreement between the 
governments involved has been reached, the substance shall be carried under 
the most severe conditions proposed. As soon as possible, but not later than 
ninety days after its first carriage, the Administration concerned shall notify 
the Organization and provide details of the substance and the provisional assess- 
ment for prompt circulation to all Parties for their information and consider- 
ation. The Government of each Party shall have a period of ninety days in which 
to forward its comments to the Organization, with a view to the assessment of 
the substance. 
Regulation 4 
OTHER LIQUID SUBSTANCES 
(1) The substances listed in Appendix III to this Annex have been evaluated 
and found to fall outside the Categories A, B, C and D, as defined in Regulation 
3(1) of this Annex because they are presently considered to present no harm 
to human health, marine resources, amenities or other legitimate uses of the 
sea, when discharged into the sea from tank cleaning or deballasting operations. 
(2) The discharge of bilge or ballast water or other residues or mixtures 
containing only substances listed in Appendix III to this Annex shall not be 
subject to any requirement of this Annex. 
(3) The discharge into the sea of clean ballast or segregated ballast shall not 
be subject to any requirement of this Annex. 
Regulation 5 
DISCHARGE OF NOXIOUS LIQUID SUBSTANCES—CATEGORIES A, B AND C SUBSTANCES 
OUTSIDE SPECIAL AREAS AND CATEGORY D SUBSTANCES IN ALL AREAS 
Subject to the provisions of Regulation 6 of this Annex— 
(1) The discharge into the sea of substances in Category A as defined in 
Regulation 3(1)(a) of this Annex or of those provisionally assessed as such 
or ballast water, tank washings, or other residues or mixtures containing such 
substances shall be prohibited. If tanks containning such substances or mixtures 
are to be washed, the resulting residues shall be discharged to a reception 
facility until the concentration of the substance in the effluent to such facility 
is at or below the residual concentration prescribed for that substance in column 
III of Appendix II to this Annex and until the tank is empty. Provided that the 
residue then remaining in the tank is subsequently diluted by the addition of a 
