Oil Tanker design under scrutiny at IMO environmental meeting

Marine Environment Protection Committee - 46th session: 23-27 April 2001

A new global timetable for accelerating the phase-out of single-hull oil tankers is one of a raft of significant environmental measures to be addressed by the 46th session of the International Maritime Organization's Marine Environment Protection Committee (MEPC) this week.

During the week-long meeting (April 23rd - 27th) at IMO headquarters in London, the Committee is expected to adopt revised legislation that will have a major impact in minimising pollution by oil tankers.

It will see single-hull tankers scrapped several years earlier than previously required and all single hull oil tankers eliminated completely by 2017 or earlier. Double-hull tankers offer greater protection of the environment from pollution in the case of certain accidents.

Other key environmental issues on a packed agenda include putting the final touches to a draft convention to eliminate the use of toxic anti-fouling paints on ships, deciding crucial issues regarding preventing or minimising the carriage of harmful organisms in ships' ballast water and the prevention of air pollution from ships.

Phase-out schemes

The plan to accelerate the phasing-out of single-hull tankers is contained in a revised regulation 13G of Annex I to MARPOL 73/78, (the international convention that deals with pollution from ships) which the Committee is expected to adopt. The proposed amendments were considered and approved by the last meeting of the MEPC in October 2000 and later circulated to all IMO Member States.

Two alternatives for phasing-out single-hull tankers are set out in the draft revision. Both would see Category 1 vessels phased-out progressively between 1 January 2003 and 1 January 2007, depending on their year of delivery.

Category 2 tankers delivered in 1986 or earlier would be phased out after their 25th year of operation under both schemes, but Category 2 ships delivered after 1986 would be phased out between 2012 and 2015 under Alternative A and between 2012 and 2017 under Alternative B.

For Category 3 tankers, both alternatives entail progressive phasing out of tankers delivered in or before 1987 between 2003 and 2013, but ships delivered after 1987 would be phased out between 2013 and 2015 under Alternative A and between 2013 and 2017 under Alternative B.

The meeting will be tasked with selecting which of the two alternatives will form the basis of the new legislation. It will also deal with submissions that propose modifications to both schemes, while retaining the same final cut-off dates, and another that argues against radical changes to regulation 13G altogether on both economic and safety grounds.

The existing regulation 13G already legislates for the phasing-out of single-hull tankers but over a more protracted period. A key component of the proposed new regulation 13G is a Condition Assessment Scheme (CAS) to which ships seeking to trade beyond certain specified lifetimes would be subject. The purpose is to ensure the structural quality of tankers is maintained at an acceptable level as they grow older and closer to their eventual withdrawal date. Preliminary details of the CAS were agreed at an inter-sessional working group of the MEPC in London in February.

MEPC 46 will consider the draft CAS and a related MEPC resolution by which it would be formally adopted. Although the CAS does not specify structural standards in excess of the provisions of other IMO conventions, codes and recommendations, its requirements stipulate more stringent and transparent verification of the reported structural condition of the ship and that documentary and survey procedures have been properly carried out and completed.

As currently envisaged, the CAS applies to category 1 and 2 oil tankers and compliance with it will be assessed during the enhanced survey programme, concurrent with intermediate or renewal surveys already required.

While much of the attention surrounding so-called "post-Erika measures" has centred on the phase-out of single-hull tankers, it is only one of several areas under consideration in the quest to eliminate sub-standard oil tankers.

The meeting will be also hearing from various of its technical sub-committees about their progress in developing other such measures in what represents a co-ordinated effort by IMO to reduce the risk of damage to the environment from these ships.

Convention to outlaw TBT and other organotin compounds in marine anti-foulants

The effects of oil pollution may be dramatic but there are other, more insidious ways in which ships may adversely affect the environment and the MEPC will be dealing with several of these, too. Many existing anti-fouling paints used by ships to prevent barnacles and other marine life attaching themselves to ships' hulls work by slowly leaching metallic compounds into the sea. But studies have shown that these compounds persist in the water, killing sea life, harming the environment and possibly entering the food chain. One of the most effective types of antifouling paint, developed in the 1960s, contains the organotin tributyltin (TBT), which has been proven to cause deformations in oysters and sex changes in whelks.

A diplomatic conference will be held in October to adopt a Convention on the Control of Harmful Anti-fouling Systems. The essence of the Convention is that ships should no longer be allowed to apply organotin compounds after 1 January 2003, leading to a complete ban by 1 January 2008.

Under the terms of the proposed new Convention, ships above a certain size would be required to have their anti-fouling systems surveyed and to carry an anti-fouling certificate. Anti-fouling systems to be prohibited or controlled would be listed in Annex I of the Convention. Initially, the annex would include reference to "organotin compounds which act as biocides in anti-fouling systems".

The Convention would allow for other substances to be included in the Annex and sets out a procedure for doing this: a proposal for a particular substance to be prohibited or restricted would be put before a group established by IMO which would assess the adverse affects of the particular anti-fouling system. The Convention would provide an agreed format for an international anti-fouling certificate and set out procedures for survey and certification.

Although the MEPC approved in principle a draft Convention at its 45th meeting last October, a number of issues remain open for discussion before the planned conference later this year. One of the issues likely to be most keenly debated at MEPC 46 is that of whether ships should be allowed to over-paint existing TBT coatings with a sealer or be required to sandblast back to bare steel in order to comply with the Convention's requirements.

The nature and make-up of the group mandated to review substances proposed in the future for prohibition and control will also be addressed, as will the size of vessels to which the Convention will apply and its requirements for entering into force.

Reducing the effects of harmful organisms in ships' ballast water

The management of ballast water has become an important issue in international efforts to reduce pollution from ships. When a ship takes on ballast water, it may also inadvertently ingest a soup of microscopic aquatic organisms, some of which may be toxic, others potentially harmful if removed from their own local ecosystem and introduced into another when discharged. Alien species that have no natural enemies can reproduce dramatically and cause tremendous damage.

The MEPC is currently working towards convening a Diplomatic Conference to adopt a Convention on the management and control of ballast water in 2003. The tasks before MEPC 46 will be to finalize the key issues and progress further the drafting of the instrument.

A working group will be convened during the meeting to push this work forward. Members have been invited to submit specific proposals on the development of standards for ballast water management and for the procedure for their adoption. Among other things, debate is expected to centre around whether the standards enshrined in the Convention should refer to the specification of systems and equipment that ships would be required to install or to the quality of ballast water ships would be allowed to discharge.

Once this decision has been made, the details of the standards themselves can be developed. The proposed new instrument is based on a so-called "two-tier" approach.

Tier 1 includes requirements that would apply to all ships, such as mandatory requirements for a Ballast Water and Sediments Management Plan, a Ballast Water Record Book and a requirement that new ships shall carry out ballast water and sediment management procedures to a given standard or range of standards. Existing ships would be required to carry out ballast water management procedures after a phase-in period, but these procedures may differ from those to be applied to new ships.

Tier 2 includes special requirements which may apply in certain areas and would include procedures and criteria for the designation of such areas in which additional controls may be applied to the discharge and/or uptake of ballast water. The text for Tier 2 remains to be developed.

Ballast water exchange at sea is currently the only widely used technique for preventing the spread of unwanted aquatic organisms in ships' ballast water. But this technique has a number of limitations. Ship safety is a main concern, with weather and sea conditions playing a critical role in determining when 'at-sea exchange' is safe. It is, however, likely that new ships will be designed to accommodate ballast exchange in a much wider range of circumstances. Moreover, the percentage of organisms successfully removed by the method depends largely on the type of organism. To this end, MEPC 46 is expected to finalise and adopt a joint MEPC/MSC Circular emphasising the need for ballast water and sediment management options to be taken into account when developing and building new ships.

Ship Recycling

A key issue for MEPC is to determine IMO's role in the recycling of ships, the terminology used to refer to ship scrapping. After a fairly heated debate at MEPC 44 the Committee agreed to establish a correspondence group to research this issue and provide a range of information about current ship recycling practices and suggestions on the role of IMO. The comprehensive report of the correspondence group will be presented to the Committee: MEPC 46 will then need to determine the way ahead in this controversial issue.

Special Areas and Particularly Sensitive Sea Areas

MEPC 46 will review new draft Guidelines for the Designation of Special Areas under MARPOL 73/78 and new draft Guidelines for the Identification of Particularly Sensitive Sea Areas (PSSAs). In Annexes I, II and V, MARPOL 73/78 defines certain sea areas as "special areas" in which, for technical reasons relating to their oceanographical and ecological condition and to their sea traffic, the adoption of special mandatory methods for the prevention of sea pollution is required.

Under the Convention, these special areas are provided with a higher level of protection than other areas of the sea. A PSSA is an area that needs special protection through action by IMO because of its significance for recognized ecological or socio-economic or scientific reasons and which may be vulnerable to damage by international maritime activities. The previous meeting of the Committee (MEPC 45) agreed additional material to be drafted in advance of the current, MEPC 46, which is scheduled to approve the revised guidelines in the form of a draft Assembly resolution. This additional material includes a flow-chart to assist Member States in deciding the most appropriate measures in providing protection to sensitive sea areas. After approval, the proposed draft resolution is to be put forward to the 22nd Assembly in November 2001 for adoption.

The Committee will consider an application by the United States for the marine area around the Florida Keys to become a PSSA.

Other issues

Among a host of other issues to be decided at the meeting, MEPC 46 will discuss the development of a formal IMO policy on greenhouse gas emissions from ships, with a view to developing an emission standard for ships. It will consider and approve the Organization's report to the UN Commission on Sustainable Development as part of the so-called "Rio + 10" process.

The working group on implementation of the OPRC Convention will receive a detailed report from France about the clean-up operation following the sinking of the Erika. It will also further develop the issues to be subject of the 3rd International R&D Forum to be held in Brest, France in March 2002, which will examine research and development of new technology in oil spill response, particularly regarding spills of high density or heavy oils like bunker oil.

The 46th session of the Marine Environment Protection Committee will be chaired by Mr Mike Julian from Australia and will be held at IMO Headquarters in London between April 23rd and 27th.


1. Category 1 -- Oil tankers of 20,000 tons deadweight and above carrying crude oil, fuel oil, heavy diesel oil or lubricating oil as cargo, and of 30,000 tons deadweight and above carrying other oils, which do not comply with the requirements for protectively located segregated ballast tanks (commonly known as Pre-MARPOL tankers).

2. Category 2 - Oil tankers of 20,000 tons deadweight and above carrying crude oil, fuel oil, heavy diesel oil or lubricating oil as cargo, and of 30,000 tons deadweight and above carrying other oils, which do comply with the protectively located segregated ballast tank requirements (MARPOL tankers).

3. Category 3 - Oil tankers of 5,000 tons deadweight and above but less than the tonnage specified for Category 1 and 2 tankers.