Oil Pollution – Prevention, Preparedness, Response and Cooperation

During the last few decades of the 20^th century, the pollution of the world’s oceans has become a matter of increasing international concern. Substantial contributors to marine pollution come from land-based sources including the by-products of industry, run-off from agriculture activities such as biocides as well as effluents from urban areas.

Nevertheless, a significant amount of marine pollution is caused by shipping and maritime activities, generally.  In tonnage terms, the most important pollutant resulting from maritime activities is oil.

Tankers and the environment

Until the late 1960s, it had been almost taken for granted that the oceans were so vast that they would be able to cope with whatever pollution and wastes were dumped into them. It was recognized that ships, especially oil powered ships, could cause pollution and both the United Kingdom and the United States introduced legislation in the 1920s to curb discharges of oil resulting from operations such as tank cleaning. Attempts to tackle the problem at an international level were unsuccessful, however, and the outbreak of World Wear II resulted in the problem being deferred.

The potential for oil to pollute was finally recognised by the International Convention for the Prevention of Pollution of the Sea by Oil, 1954 (OILPOL 1954), which was adopted in London at a conference organized by the United Kingdom. The Convention provided for certain functions to be undertaken by the International Maritime Organization when it came into being. In fact, the IMO Convention entered into force in 1958 just a few months before the OILPOL convention, so IMO effectively managed OILPOL from the start, initially through its Maritime Safety Committee.[1]

It is significant that the OILPOL Convention recognised that most oil pollution resulted from routine shipboard operations such as the cleaning of cargo tanks.  In the 1950s, the normal practice was simply to wash the tanks out with water and then pump the resulting mixture of oil and water into the sea.  OILPOL 54 prohibited the dumping of oily wastes within a certain distance from land and in 'special areas' where the danger to the environment was especially acute.  In 1962, the limits were extended by means of an amendment adopted at a conference organised by IMO.

Meanwhile, IMO in 1965, set up a Subcommittee on Oil Pollution, under the auspices of its Maritime Safety committee, to address oil pollution issues. But the possibility of massive pollution resulting from a tanker accident was not seriously recognized until 1967, when the Torrey Canyon ran aground while entering the English Channel and spilled her entire cargo of 120,000 tons of crude oil into the sea.  This resulted in the biggest oil pollution incident ever recorded up to that time.  The incident raised questions about measures then in place to prevent oil pollution from ships and also exposed deficiencies in the existing system for providing compensation following accidents at sea.

These series of photographs are taken off the Torrey Canyon disaster.

It was essentially this incident that set in motion the chain of events that eventually led to the adoption of MARPOL - as well as a host of Conventions in the field of liability and compensation.[2]

First, IMO called an Extraordinary Session of its Council, which drew up a plan of action on technical and legal aspects of the Torrey Canyon incident. [3]

It was still recognized, however, that although accidental pollution was spectacular, operational pollution was the bigger threat. In 1969, therefore, the 1954 OILPOL Convention was again amended, this time to introduce a procedure known as 'load on top' which had been developed by the oil industry and had the double advantage of saving oil and reducing pollution.  Under the system, the washings resulting from tank cleaning are pumped into a special tank.  During the voyage back to the loading terminal the oil and water separate.  The water at the bottom of the tank is pumped overboard and at the terminal oil is pumped on to the oil left in the tank. [4]

At the same time, the enormous growth in the maritime transport of oil and the size of tankers, the increasing amount of chemicals being carried at sea and a growing concern for the world's environment as a whole, made many countries feel that the 1954 OILPOL Convention was no longer adequate, despite the various amendments which had been adopted.

In 1969, the IMO Assembly decided to convene an international conference to adopt a completely new convention, which would incorporate the regulations contained in OILPOL 1954 (as amended).  At the same time, the Sub-Committee on Oil Pollution was renamed the Sub-Committee on Marine Pollution, to broaden its scope, and this became the Marine Environment Protection Committee (MEPC), which was eventually given the same standing as the Maritime Safety Committee, with a brief to deal with all matters relating to marine pollution.

The conference was set for October-November 1973, and preparatory meetings began in 1970. Meanwhile, in 1971 IMO adopted amendments to OILPOL 1954, which limited the size of cargo tanks in all tankers ordered after 1972. The intention was that given certain damage to the vessel, only a limited amount of oil could enter the sea.

 

1973 International Convention for the Prevention of Pollution from Ships (MARPOL)

The 1973 conference was attended by representatives from 71 countries and resulted in the adoption of the most ambitious international treaty covering marine pollution ever adopted. The Convention incorporated much of OILPOL 1954 and its amendments into Annex I, covering oil, while other annexes covered chemicals, harmful substances carried in packaged form, sewage and garbage.

            Annex I expanded and improved on OILPOL in several ways. It specified requirements for continuous monitoring of oily water discharges and included the requirement for Governments to provide shore reception and treatment facilities at oil terminals and ports. It also established a number of Special Areas in which more stringent discharge standards were applicable, including the Mediterranean, Red Sea and Gulf, and Baltic Seas. These special areas would be implemented when the littoral States concerned had provided adequate reception facilities for dirty ballast and other oily residues.

            An important regulation of Annex I was Regulation 13 which required segregated ballast tanks on new tankers over 70,000 deadweight tonnes.   The aim was to ensure that ballast water (taken on board to maintain stability, such as when a tanker is sailing empty to pick up cargo) is never going to be contaminated by oil carried as cargo or fuel.

This regulation was initially opposed by States with large shipowning interests, but ultimately the fact that there was, at the time, sufficient tonnage to provide capacity for another decade, led to the regulation being accepted.[5] However, a proposal strongly pushed by the United States for a requirement for double bottoms was not accepted.[6]

Despite doubts expressed over States' willingness to ratify the Convention, one commentator noted:  "The 1973 Conference - especially from an historical perspective - was a landmark in international environmental regulation. For the first time the installation is required of those ship and shore technologies necessary for the retention on board and proper port disposal of oil residues."[7]

As it turned out, there was slow progress at ratifying the Convention and the non-ratification of MARPOL became a major concern. At the same time, a series of tanker accidents in 1976-1977, mostly in or near United States waters and including the stranding of the Argo Merchant,[8] led to demands for more stringent action to curb accidental and operational oil pollution.

At the same time, a series of tanker accidents in 1976-1977, mostly in or near United States waters and including the stranding of the Argo Merchant,[9] led to demands for more stringent action to curb accidental and operational oil pollution.

The United States took the lead in asking the IMO Council, in May 1977, to consider adopting further regulations on tanker safety. The Council agreed to convene a Conference in February 1978 - the Conference on Tanker Safety and Pollution Prevention.  A working group met in May, June and July, and a combined MSC/MEPC met in October, to prepare basic documents for the Conference.

1978 Conference on Tanker Safety and Pollution Prevention

The Conference held in February 1978, was attended by delegates from 61 States, observers from three States and representatives from 17 international organizations - a total of 451 people.

The Conference adopted a protocol to the 1973 MARPOL Convention, absorbing the parent Convention and expanding on the requirements for tankers to help make them less likely to pollute the marine environment.

The Protocol expanded the requirements for segregated ballast tanks to all new crude oil tankers of 20,000 dwt and above and all new product carriers of 30,000 dwt and above. The Protocol also required segregated ballast tanks to be protectively located, in other words, placed in areas of the ship where they will minimise the possibility of and amount of oil outflow from cargo tanks after a collision or grounding.

New tankers over 20,000 dwt were required to be fitted with crude oil washing system. Crude oil washing, or COW, is the cleaning or washing of cargo tanks with high pressure jets of crude oil. This reduces the quantity of oil remaining on board after discharge.

The Protocol also called for existing tankers over 40,000 dwt to be fitted with either segregated ballast tanks or crude oil washing systems; while for an interim period, it also allowed for some tankers to use clean ballast tanks, whereby specific cargo tanks are dedicated to carry ballast water only.

Additional measures for tanker safety were incorporated into the 1978 Protocol to the International Convention for the Safety of Life at Sea (SOLAS), 1974. These included the requirement for inert gas systems (whereby exhaust gases, which are low in oxygen and thus incombustible, are used to replace flammable gases in tanks) on all new tankers over 20,000 dwt and specified existing tankers. The SOLAS Protocol also included requirements for steering gear of tankers; stricter requirements for carrying of radar and collision avoidance aids; and stricter regimes for surveys and certification.

Before the MARPOL convention was adopted, tankers were generally built with only one hull. The hull itself was divided into a series of tanks, but this was primarily for reasons of structural integrity than as a way of minimizing accidental oil spills. Nowadays most tankers have double hulls, the idea being that if the outer hull is penetrated the inner hull will still retain the cargo on board.

In order to speed up implementation of MARPOL, the Conference allowed that the Parties "shall not be bound by the provisions of Annex II of the Convention for a period of three years" from the date of entry into force of the Protocol, so that countries could accept Annex I and have three years to implement Annex II.

Both the 1978 MARPOL and SOLAS Protocols were seen as major steps in raising construction and equipment standards for tankers through more stringent regulations. Furthermore, a number of nations, such as the United States, made clear their commitment to pushing through the legislation to make the regulations mandatory and this was seen as help in spurring on other maritime nations, keen to protect their shipowners' competitiveness, into ratifying the Convention.

If the world needed further reminder of the need for strict regimes to control oil pollution, it got it just one month after the 1978 Conference, when the Amoco Cadiz ran aground off Brittany, giving France its worst oil spill ever. The tanker, filled with 223,000 tons of crude oil, lost its entire cargo, covering more than 130 beaches in oil. In places, the oil was up to 30 cm thick.

Sufficient States had ratified MARPOL by October 1982, and the MARPOL 1973/78 Convention entered into force on 2 October 1983.

Estimate of oil entering the oceans in 1979

(Metric tonnes per anum)

Source: The Impact of Marine Pollution. Douglas J. Cuisine and John P. Grant. Croom Helm Ltd. London 1980.

Oil pollution from ships probably reached its peak in 1979.  Despite the publicity that oil spills always attract, even in 1979 only a small fraction of the oil entering the sea came from tanker accidents. Most came from routine operations – and discarded lubricants – such as engine oil poured into drains – accounted for a much higher percentage of the total. Since 1979, the amount of sea getting into the sea as a result of shipping operations has declined dramatically.

 

The 1984 amendments

While MARPOL Annex I had entered into force, there was still work to be done in reviewing the Convention and ensuring it was being implemented.

The first amendments to MARPOL 73/78 were adopted in 1984, entering into force in 1986. They were designed to improve and strengthen existing provisions, such as Regulation 25 concerning subdivision and stability - intended to ensure that tankers can survive assumed damage. Certain provisions were waived, or relaxed, for example carriage of ballast water in cargo tanks was now permitted in certain circumstances, based on studies presented to the MEPC showing that this was appropriate.

In 1991, further amendments to Annex I, which entered into force in 1993, introduced a new chapter, requiring oil tankers and other ships[10] to carry a shipboard oil pollution emergency plan detailing the procedure to be followed in reporting an oil pollution incident, authorities to be contacted in the event of an oil pollution incident, a description of the action which must be taken and the procedures and point of contact on the ship for co-ordinating shipboard actions with national and local authorities.

Although tanker accidents are comparatively rare and result in only a small fraction of the total amount of oil entering the sea each year, some accidents have caused very serious local pollution and have had a major impact on the development of environmental legislation. They include the Argo Merchant spill on 1976 (below), the Amoco Cadiz in 1978 (top left) and the Exxon Valdez in 1989 (top right).

But it was another tanker accident that led to one of the most important changes to be made to the Convention since the adoption of the 1978 Protocol.

In March 1989, the Exxon Valdez, loaded with 1,264,155 barrels of crude oil, ran aground in the north-eastern portion of Prince William Sound, spilling about one-fifth of its cargo. It was the largest crude spill, to date, in US waters and - probably the one that gained the biggest media coverage to date. The U.S. public demanded action - and duly got it.

The United States introduced its Oil Pollution Act of 1990 (OPA 90), making it mandatory for all tankers calling at U.S. ports to have double hulls.

The United States also came to IMO, calling for double hulls this time to be made a mandatory requirement of MARPOL. The implications of the Exxon Valdez spill were not lost on IMO Members, and the MEPC began discussions on how the U.S. proposals could be implemented.[11]

As on previous occasions[12], there was some resistance on the part of the oil industry to double hulls being made mandatory, due mainly to the cost of retrofitting existing tankers.

At the same time, several of IMO's Member States said that other designs should be accepted as equivalents and that measures for existing ships should also be contemplated.  In 1991 a major study into the comparative performances of the double-hull and mid-height deck tanker designs was carried out by IMO, with funding from the oil and tanker industry.

It concluded in January 1992 that the two designs could be considered as equivalent, although each gives better or worse outflow performance under certain conditions. Eventually, the MEPC agreed to make mandatory double hulls or alternative designs "provided that such methods ensure the same level of protection against pollution in the event of a collision or stranding".  These design methods must be approved by the MEPC.  The amendments introducing double hulls (or an alternative) were contained in Regulation 13F, adopted in March 1992 and entering into force in July 1993. Regulation 13F applies to new tankers - defined as delivered on or after 6 July 1996 - while existing tankers must comply with the requirements of 13F not later than 30 years after their date of delivery.

Tankers of 5,000 dwt and above must be fitted with double bottoms and wing tanks extending the full depth of the ship's side.  The regulation allows mid-deck height tankers with double-sided hulls, such as those developed by Japanese and European shipbuilders, as an alternative to double hull construction.

Oil tankers of 600 dwt and above but less than 5,000 dwt, must be fitted with double bottom tanks and the capacity of each cargo tank is limited to 700 cubic metres, unless they are fitted with double hulls. The MEPC also adopted Regulation 13G, concerned with existing tankers, which makes provision for an enhanced programme of inspections to be implemented, particularly for tankers more than five years old.

This graphic, based on Clarkson’s Quarterly Ships Register, October 1997 and information provided by Japan, shows the age and size of the tanker fleet. It shows clearly how old the tanker fleet is, thanks to the overbuilding that occurred in the 1970s and how high is the number of single hulled ships. While there is general acceptance of the fact that double hulls offer better environmental protection, it would be impossible simply to scrap single hulls without disastrous effects on the global economy – there are simply not enough double-hulled ships to carry the oil required.

Regulation 13G also allowed for future acceptance of other structural or operational arrangements - such as hydrostatic balance loading (HBL)[13] - as alternatives to the protective measures in the Regulation.

It was anticipated that many older tankers which could not be brought up to the new standard economically, would be scrapped and the MEPC adopted a resolution recommending that Member Governments take initiatives in co-operation with the shipbuilding and shipping industries, to develop scrapping facilities at a world-wide level, to promote research and development programmes and to provide technical assistance to developing countries in developing ship scrapping facilities.

The MEPC also adopted amendments to MARPOL drastically reducing the amount of oil which can be discharged into the sea as a result of routine operations, by forbidding non-tankers to discharge oily wastes if the oil content exceeds 15 parts per million (an amount which is virtually undetectable), and permitting tankers to discharge oily mixtures only at a rate of 30 litres per nautical mile  (and only outside special areas). In November 1994, the MEPC adopted amendments to MARPOL aimed at improving implementation of the Convention, by   making it possible for ships to be inspected when in the ports of other Parties to the Convention, to ensure that crews are able to carry out essential shipboard procedures relating to marine pollution prevention.

The amendments, which entered into force on 3 March 1996, also applied to Annex II, which is concerned with pollution by noxious liquid substances (such as chemicals); Annex III, containing regulations for the prevention of pollution by harmful substances in packaged form; and Annex V, which deals with garbage.

Similar amendments were made to the International Convention for the Safety of Life at Sea (SOLAS), 1974 in May 1995. A number of IMO Conventions contain provisions for port State control inspections but previously these have been limited primarily to certification and the physical condition of the ship and its equipment.

Extending port State control to operational requirements was seen as an important way of improving the efficiency with which international safety and anti-pollution treaties are implemented.

In September 1997, the MEPC adopted a new Regulation 25A to Annex 1, specifying intact stability criteria for double hull tankers. The amendments, which enter into force on 1 February 1999, were deemed necessary after experience had shown that a small number of double hull tankers were being constructed without enough bulkheads to maintain stability. The regulation, which is technical in nature, defines the criteria for achieving intact stability for double hull tankers.

Another amendment made the North West European waters a "special area” from 1 August 1999, thereby prohibiting discharge into the sea of oil or oily mixture from any oil tanker and ship over 400 gt in the North Sea and its approaches, the Irish Sea and its approaches, the Celtic Sea, the English Channel and its approaches and part of the North East Atlantic immediately to the West of Ireland, from the time when littoral States have made provision for adequate reception facilities.

 

MARPOL Annex I - achievements

In 1990, the National Research Council Marine Board of the United States credited MARPOL 73/78 with making "a substantial positive impact in decreasing the amount of oil that enters the sea".

A study carried out by the Board showed that in 1981, some 1,470,000 tons of oil entered the world's oceans as a result of shipping operations.  Most of it came from routine operations, such as discharges of machinery wastes and tank washings from oil tankers (the latter alone contributed 700,000 tons).  Accidental pollution contributed less than 30% of the total. [14]

There is no doubt, therefore, that the MARPOL 73/78 Convention has made a significant impact on oil pollution from ships. Nonetheless, IMO Member States continue to approach IMO where they feel there is room for improvement. There is still concern over the fact that a number of important oil producing and exporting nations have so far failed to ratify MARPOL.

One reason may be that these countries would be obliged to provide reception facilities for oily wastes.  The costs of doing so could be great, since most tank cleaning operations take place during the ballast stage of the tanker's voyage: the reception facilities required at an oil loading port, therefore, are much greater than those needed elsewhere.

All of this makes life very difficult for tanker owners and crew.  MARPOL greatly limits the discharge of wastes into the sea and in some areas bans it completely: but if the ports fail to provide the reception facilities the captain of the ship has to dispose of the wastes in some other way.  The temptation is to do this illegally - and hope that no one finds out.

IMO is addressing the problem of inadequate reception facilities and the MEPC is currently looking at the best mechanisms for financing port reception facilities. It is also involved in a number of technical co-operation projects to help developing countries implement MARPOL requirements.

Despite the fact that tanker traffic is much safer now than it was twenty years ago, every so often an accident occurs. This was the case in December 1998, when the tanker Erika broke up off the western coast of France, resulting in massive coastal pollution.

This led to renewed calls for further action to be taken to improve the safety of tankers and in October 2000 IMO agreed on the first, formal step towards a global timetable for the accelerated phasing-out of single-hull oil tankers. The approval paves the way for the adoption of a revised regulation 13G of MARPOL at in April 2001 to accommodate the swiftest possible introduction of new rules. In its draft revision of MARPOL regulation 13G, the MEPC working group identified three categories of tankers:

•    Category 1 oil tanker means 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).

•    Category 2 oil tanker means 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).

•    Category 3 oil tanker means an oil tanker of 5,000 tons deadweight and above but less than the tonnage specified for Category 1 and 2 tankers.

The amendment to Annex 1 The draft revision sets out two clear alternative schemes, A and B, for phasing-out single-hull tankers. Both schemes 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 built in 1986 or earlier would be phased out after their 25th year of operation under both schemes, but Category 2 ships built 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 schemes entail progressive phasing out of tankers built in or before 1987 phased-out between 2003 and 2013, but ships built after 1987 would be phased out between 2013 and 2015 for ships under scheme A and between 2013 and 2017 under scheme B.

The working group also agreed that continued operation of Category 2 oil tankers beyond 2010 should only be permitted to high quality ships that had been subject to a Condition Assessment Scheme (CAS). There was general agreement at the meeting that phasing-out of single-hull tankers should be seen as just one of several measures needed to help eliminate sub-standard tankers. To this end, the working group drew up a preliminary list of topics to be considered in this regard. The Committee invited the Maritime Safety Committee (MSC) to establish a working group at MSC 73, in November 2000, to examine fully all the measures listed and, initially, separate the list into maritime safety and environmentally related issues.

In a related development, IMO’s MEPC agreed to hold a Research and Development Forum in March 2002, which will focus primarily on response to spills of high-density oil. France will host the forum, which will be the third R&D Forum sponsored by IMO. High-density fuel oils, or heavy fuel oil, such as that carried by the Erika, are among the most difficult and most costly to deal with when spilled because of their highly persistent nature and the damage they cause to the marine environment.

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[1]IMO's twin objectives today are stated as "the safety of shipping and the prevention of marine pollution by ships", but marine pollution was not specifically mentioned in the original IMO Convention, adopted in 1948. In 1975, however, the IMO Assembly adopted amendments to the IMO Convention, changing its name from Inter-Governmental Maritime Consultative Organization (IMCO) to IMO and changing Article I by adding to the list of purposes "the prevention and control of marine pollution from ships; and to deal with legal matters related to the purposes set out in this Article." The amendments entered into force in 1982.

[2]The Torrey Canyon incident is also seen as the turning point for IMO as an Organization, to the extent that IMO went on to expand its activities in the environmental and legal fields.

[3]An ad-hoc Legal Committee was established, which later became a permanent subsidiary organ of the IMO Council. International Conventions on liability and compensation followed, including the International Convention Relating to Intervention on the High Seas in Cases of Oil Pollution Casualties (INTERVENTION), 1969; the International Convention on Civil Liability for Oil Pollution Damage (CLC), 1969;  and the International Convention on the Establishment of an International Fund for Compensation for Oil Pollution Damage (FUND), 1971

[4]The amendment entered into force in 1978, but was incorporated into MARPOL 1973.

[5]Pollution, Politics and International law, Tankers at Sea. R. Michael M'Gonigle and Mark W. Zacher. University of California Press. 1979. p. 114.

[6]Double hulls were introduced in the 1992 amendments to MARPOL following the Exxon Valdez disaster.

[7] Pollution, Politics and International law, Tankers at Sea. R. Michael M'Gonigle and Mark W. Zacher. University of California Press. 1979. p. 120.

[8]The Argo Merchant ran aground off Massachussetts in December 1976. It was a small tanker, carrying 27,000 tons of oil, but caused huge public concern as the oil slick threatened New England resorts  and Georges Bank fishing ground.

[9]The Argo Merchant ran aground off Massachussetts in December 1976. It was a small tanker, carrying 27,000 tons of oil, but caused huge public concern as the oil slick threatened New England resorts  and Georges Bank fishing ground.

[10] Applies to oil tankers of 150 gross tons and above and ships other than tankers of 400 gt and above

[11] Another consequence of the Exxon Valdez disaster was the adoption in 1990 of an International Convention on Oil Pollution Preparedness, Response and Co-operation (OPRC), to provide a global framework for international co‑operation in combating major incidents or threats of marine pollution.

[12]The United States had called for double hulls to be made mandatory at both the 1973 and 1978 Conferences

[13]  Hydrostatic balance loading (HBL)  is based on the principle that if a hull is breached, the pressure from outside would be greater than that from the oil inside so seawater would flow in, pushing the oil upwards through non-return valves into ballast tanks; rather than an outflow of oil into the sea.

[14]See Focus on IMO - MARPOL