GUIDELINES FOR DISCHARGE REQUIREMENTS UNDER
MARPOL ANNEXES I AND II
1 Introduction
1.1 Regulations 15 and 34 of MARPOL Annex I prohibit the discharge into the sea of oil
and regulation 13 of Annex II prohibits the discharge into the sea of noxious liquid substances
except under precisely defined conditions. A record of these operations shall be completed,
where appropriate, in the form of an Oil or Cargo Record Book as applicable and shall be kept
in such a place as to be readily available for inspection at all reasonable times.
1.2 The regulations referred to above provide that whenever visible traces of oil are
observed on or below the surface of the water in the immediate vicinity of a ship or of its wake,
a Party should, to the extent that it is reasonably able to do so, promptly investigate the facts
bearing on the issue of whether or not there has been a violation of the discharge provisions.
1.3 The conditions under which noxious liquid substances are permitted to be discharged
into the seas include quantity, quality and position limitations, which depend on category of
substance and sea area.
1.4 An investigation into an alleged contravention should therefore aim to establish
whether a noxious liquid substance has been discharged and whether the operations leading
to that discharge were in accordance with the ship’s Procedures and Arrangements Manual
(P and A Manual).
1.5 Recognizing the likelihood that many of the violations of the discharge provisions will
take place outside the immediate control and knowledge of the flag State, article 6 of MARPOL
provides that Parties shall cooperate in the detection of violations and the enforcement of the
provisions using all appropriate and practicable measures of detection and environmental
monitoring, and adequate procedures for reporting and gathering evidence. MARPOL also
contains a number of more specific provisions designed to facilitate that cooperation.
1.6 Several sources of information about possible violations of the discharge provisions
can be indicated. These include:
.1 reports by masters: article 8 and Protocol I of MARPOL require, inter alia, a
ship’s master to report certain incidents involving the discharge or the
probability of a discharge of oil or oily mixtures, or noxious liquid substances
or mixtures containing such substances;
.2 reports by official bodies: article 8 of MARPOL requires furthermore that a
Party issue instructions to its maritime inspection vessels and aircraft and to
other appropriate services to report to its authorities incidents involving the
discharge or the probability of a discharge of oil or oily mixtures, or noxious
liquid substances or mixtures containing such substances;
.3 reports by other Parties: article 6 of MARPOL provides that a Party may
request another Party to inspect a ship; the Party making the request shall
supply sufficient evidence that the ship has discharged oil or oily mixtures,
noxious liquid substances or mixtures containing such substances, or that
the ship has departed from the unloading port with residues of noxious liquid
substances in excess of those permitted to be discharged into the sea; and
.4 reports by others: it is not possible to list exhaustively all sources of
information concerning alleged contravention of the discharge provisions;
Parties should take all circumstances into account when deciding upon
investigating such reports.
1.7 Action which can be taken by States other than the flag or port States that have
information on discharge violations (hereinafter referred to as coastal States):
.1 coastal States that are Parties to MARPOL, upon receiving a report of
pollution by oil or noxious liquid substances allegedly caused by a ship, may
investigate the matter and collect such evidence as can be collected; for
details of the desired evidence, reference is made to appendices 3 and 4;
.2 if the investigation referred to under sub-paragraph.1 above discloses that
the next port of call of the ship in question lies within its jurisdiction, the
coastal State should also take port State action as set out in paragraphs 2.1
to 2.6 below;
.3 if the investigation referred to in sub-paragraph.1 above discloses that the
next port of call of the ship in question lies within the jurisdiction of another
Party, the coastal State should in appropriate cases furnish the evidence to
that other Party and request that Party to take port State action in accordance
with paragraphs 2.1 to 2.6 below; and
.4 in either case referred to in sub-paragraphs.2 and.3 above and if the next
port of call of the ship in question cannot be ascertained, the coastal State
shall inform the flag State of the incident and of the evidence obtained.
2 Port State action
2.1 Parties shall appoint or authorize officers to carry out investigations for the purpose
of verifying whether a ship has discharged oil or noxious liquid substances in violation of the
provisions of MARPOL.
2.2 Parties may undertake such investigations on the basis of reports received from
sources indicated in paragraph 1.6 above.
2.3 These investigations should be directed towards the gathering of sufficient evidence
to establish whether the ship has violated the discharge requirements. Guidelines for the
optimal collation of evidence are given in appendices 3 and 4.
2.4 If the investigations provide evidence that a violation of the discharge requirements
took place within the jurisdiction of the port State, that port State shall either cause proceedings
to be taken in accordance with its law, or furnish to the flag State all information and evidence
in its possession about the alleged violation. When the port State causes proceedings to be
taken, it shall inform the flag State.
2.5 Details of the report to be submitted to the flag State are set out in appendix 16.
2.6 The investigation might provide evidence that pollution was caused through damage
to the ship or its equipment. This might indicate that a ship is not guilty of a violation of the
discharge requirements of MARPOL Annex I or Annex II provided that:
.1 all reasonable precautions have been taken after the occurrence of the
damage or discovery of the discharge for the purpose of preventing or
minimizing the discharge; and
.2 the owner or the master did not act either with intent to cause damage or
recklessly and with knowledge that damage would probably result.
2.7 However, action by the port State as set out in chapter 3 of these Procedures may be
called for.
3 Inspection of crude oil washing (COW) operations
3.1 Regulations 18, 33 and 35 of MARPOL Annex I inter alia require that crude oil washing
of cargo tanks be performed on certain categories of crude carriers. A sufficient number of
tanks shall be washed in order that ballast water is put only in cargo tanks which have been
crude oil washed. The remaining cargo tanks shall be washed on a rotational basis for sludge
control.
3.2 Port State authorities may carry out inspections to ensure that crude oil washing is
performed by all crude carriers either required to have a COW system or where the owner or
operator chooses to install a COW system in order to comply with regulation 18 of
MARPOL Annex I. In addition, compliance should be ensured with the operational
requirements set out in the Revised specifications for the design, operation and control of
crude oil washing systems (resolution A.446(XI), as amended). This can best be done in the
ports where the cargo is unloaded.
3.3 Parties should be aware that the inspection referred to in paragraph 3.2 may also lead
to the identification of a pollution risk, necessitating additional action by the port State as set
out in chapter 3 of these Procedures.
3.4 Detailed guidelines for in-port inspections of crude oil washing procedures have been
approved and published by IMO (Crude Oil Washing Systems, revised edition, 2000) and are
set out in part 4 of appendix 3.
4 Inspection of unloading, stripping and prewash operations
4.1 Regulation 16 of MARPOL Annex II requires Parties to MARPOL to appoint or
authorize surveyors for the purpose of implementing the regulation.
4.2 The provisions of regulation 16 are aimed at ensuring in principle that a ship having
unloaded, to the maximum possible extent, noxious liquid substances of category X, Y or Z,
proceeds to sea only if residues of such substances have been reduced to such quantities as
may be discharged into the sea.
4.3 Compliance with these provisions is in principle ensured in the case of categories X,
Y and Z substances through the application of a prewash in the unloading port and the
discharge of prewash residue water mixtures to reception facilities, except that, in the case of
non-solidifying and low viscosity categories Y and Z substances, requirements for the efficient
stripping of a tank to negligible quantities apply in lieu of the application of a prewash.
Alternatively, for a number of substances ventilation procedures may be employed for
removing cargo residues from a tank.
4.4 Regulation 16.6 permits the Government of the receiving Party to exempt a ship
proceeding to a port or terminal under the jurisdiction of another Party from the requirement to
prewash cargo tanks and discharge residue/water mixtures to a reception facility.
4.5 Existing chemical tankers engaged on restricted voyages may by virtue of
regulation 4.3 of MARPOL Annex II be exempted from the quantity limitation requirements of
regulations 12.1 to 12.3. If a cargo tank is to be ballasted or washed, a prewash is required
after unloading category Y or Z substances and prewash residue water mixtures must be
discharged to shore reception facilities. The exemption should be indicated on the certificate.
4.6 A ship whose constructional and operational features are such that ballasting of cargo
tanks is not required and cargo tank washing is only required for repairs or dry-docking may
by virtue of regulation 4.4 be exempted from the provisions of regulation 12 of MARPOL Annex
II, provided that all conditions mentioned in regulation 4.4 are complied with. Accordingly, the
certificate of the ship should indicate that each cargo tank is only certified for the carriage of
one named substance. It should also indicate the particulars of the exemption granted by the
Administration in respect of pumping, piping and discharge arrangements.
4.7 Detailed instructions on efficient stripping and prewash procedures are included in a
ship’s P and A Manual. The Manual also contains alternative procedures to be followed in case
of equipment failure.
4.8 Parties should be aware that the inspection referred to in paragraphs 1.3 and 1.4
above may lead to the identification of a pollution risk or of a contravention of the discharge
provisions, necessitating port State action as set out in chapter 3 of these Procedures.
4.9 For details in respect of inspections under this section, reference is made to
appendix 4.