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The present draft Convention proposal of Regulation 13(1), 13(2), and 13(5) represent effective measures for accomplishing this requirement. The studies already presented to IMCO on segregated-ballast adequately show the feasibility of this concept for substantially reducing operational discharges without overly burdensome costs. Additionally, the segregatedballast solution carries with it the distinct benefit of eliminating the need for monitoring; enforcement is effectively "built-in." However, the shipbuilding and ship-owning community must be permitted adequate flexibility and time to determine the most suitable design for a segregated-ballast tanker. The overly restrictive provisions of draft Regulations 13(3) and 13(4) which specify ballast quantity and limit the application to only the large newly built tankers will not achieve the most productive results.

In dealing with segregated-ballast design, the Convention should concern itself with crude carriers only, and should determine a date of application. In addition, it should specify that ships be designed so as to prohibit the introduction of ballast water in cargo tanks except to assure the safety of the tanker and its crew. With this flexibility, and a reasonable starting date for segregated ballast in newbuildings, logical design processes which capitalize on technological advances will be encouraged. Of equal importance is the freedom to pursue the most cost-effective means of implementing the segre. gated-ballast concept.

It must be recognized that some lapse of time will occur before the Convention is ratified. But this does not need to cause undue delay in implementing the segregated-ballast measure. Exxon believes that the proposed dates in Regulation 11(2) of the final draft Convention are not early enough and could be advanced by several years.

Exxon is convinced the combination of improved load-on-top for the existing crude tankers plus a change to newly built segregated-ballast tankers will show a progressive and enforceable reduction of operational oil discharges. This is totally consistent with the Convention's broad objectives.

tional abatement measures appear warranted. The development of a segregated-ballast tanker fleet will in time obviate the need for special measures in such areas. This eventual solution makes it imperative that interim measures for special areas be developed with particular emphasis on minimizing capital requirements. While Exxon is fundamentally opposed to shore reception facilities as a primary long-term crude tanker pollution-abatement measure, limited application for the special trades just described may represent the only practical solution. Our views on shore reception facilities at crude loading terminals will be discussed further in a subsequent section of this paper.

Various provisions in the draft Convention deal with the problem of "special areas" as defined in Regulation 1(10). Regulation 12 has draft provisions specifically related to the Mediterranean, calling for full shore reception facilities to be provided by January 1, 1977. The draft Convention also includes specific regulations for the Baltic and Black Seas, and possibly other areas as well. Exxon regards the basic concept of designating "special areas" as unnecessary and contrary to the broad Convention objective of ensuring uniform, enforceable and effective world-wide regulations. However, for those trades where crude ships are unable to practice LOT fully and effectively, the Convention should require at crude loading terminals the installation of shore reception facilities, with capacity limited to handling the contents of the slop tank. Acceptance of this view would mean the deletion of Regulations 1(10) and 12.

Product Loading Terminals Tankers trading in product service must control operational pollution in a distinctly different manner than crude tankers. Tank-washing slops are the predominant source of oily mixtures in product tankers. Although a variation of loadon-top can be used on product tankers, the accumulated oily slops cannot be mixed with new cargoes because of product contamination. Accordingly, product tankers must have a separate means for oil slops disposal. Exxon believes the only practical pollution abatement measure suited to the particular characteristics of product-tanker trades is a requirement for limited shore reception facilities at all product loading terminals. Most terminals are located at refinery sites where effective oil/water separation systems already exist. The segregated-ballast concept is judged to be an ineffective measure for product tankers because of the extensive tankwashing requirement and the need to avoid product contamination by accumulated oily slops.

Special Areas The two-part program outlined above may be inadequate to achieve timely pollution abatement results in certain geographical areas. In those areas where LOT cannot be effectively practiced due to:

1) a high percentage of shipments being on vessels which have an unusually short ballast voyage or

2) a predominance of shipments being on ves. sels which mainly transit coastal zones, addi


Ship Repair Ports Tankers in both crude and product trades must periodically clean all tanks prior to entering repair ports. Such cleaning efforts constitute a significant source of marine pollution. Exxon believes the most practical measure for handling oily slops from pre-repair cleaning is to mandate installation of shore reception facilities at all repair ports. Such facilities should have the capacity to receive oily residues from tank washing. Dirty ballast can be handled by the load-ontop method prior to arrival at repair areas.

Crude Loading Terminals The preceding paragraphs describe several limited circumstances in which shore reception facilities are a reasonable pollution abatement measure-when product vessels or ship repairs are involved. As far as the daily operations of crude tankers are concerned, shore reception facilities can be viewed only as an interim mea. sure since the longer-range solution rests in the development of a segregated-ballast fleet of crude tankers.

Draft Regulation 20, however, requires shore reception facilties at all oil loading and discharge terminals and ship repair ports. It proposes capabilities for handling oily mixtures without causing undue delay to ships. Any other requirements for such facilities would be independently determined by contracting govern. ments. As drafted, this regulation, together with the optional use of shore reception facilities by all ships specified in Regulation 11(1)(c), encourages the widespread adoption of shore reception facilities as the primary long-term measure for minimizing operational discharges.

Exxon is strongly opposed to Convention provisions which make shore reception facilities the primary long-term pollution abatement solution, Shore reception facilities are inherently incapable of flexible and rapid response to normal source and volume changes in crude loading patterns. Within certain national jurisdictions, it may be difficult to ensure that such facilities are constructed and used and more difficult still to regulate their operations. Inevitably, shore reception facilities will localize and substantially increase oily discharges in the coastal waters at crude loading ports. Finally, shore reception facilities are not a technically feasible measure at offshore crude loading sites.

By contrast, primary emphasis on LOT for existing tankers and segregated ballast for new crude tankers avoids all of the above ections. A further intrinsic benefit of selecting segregated ballast for new crude tankers as the primary solution is the flexibility which it provides for future adoption of alternative solutions as they

are developed. A fully automatic shipboard monitoring control or separation system could make segregated ballast and other measures unnecessary. Segregated-ballast tanks then could be converted readily and economically to useful cargo-carrying service, an advantage not shared by other pollution-abatement measures.

Accordingly. Exxon recommends that draft Regulation 20 be modified to mandate only those limited shore reception facilities which are judged necessary for the special purposes already described, i.e., short or coastal crude trades, product trades and ship repair ports.

Definition of Oil Regulation 1(1) of Annex I in the final draft Convention defines oil as meaning "petroleum in any form including crude oil, residual fuel oil, sludge, oil refuse and refined products (other than petrochemicals ).” This broad definition is supported by a detailed listing-in Appendix Iof the substances which are to be regulated under Annex 1. The effect of this provision is the regulation and control for pollution abatement of non-persistent oils as well as persistent oils. The harmfulness of non-persistent oil discharges in the open seas, or the absence of adverse effect, has not as yet been scientifically determined. Exxon holds the belief that, until more is known, non-persistent oils should be subject to the same discharge controls as those governing persistent oil discharges. In addition, clean-product movements will only represent approximately five per cent of overall international petroleum movements. In view of these two factors, we cannot see the justification for establishing different discharge controls for persistent and non-persistent oils. Our recommendations for shore reception facilities at product loading terminals is completely consistent with this belief.

Control of Oil Discharges The integrated program just described repre. sents a responsive and achievable way to meet the Convention's primary long-term objective for effective control of operational discharges. The Convention must also include regulations for realistic and enforceable discharge controls. In Exxon's view, the 1969 IMCO Amendments to the International Convention for the Prevention of Pollution of the Sea by Oil (1954) basically contain discharge regulations which are realistic. Since the 1969 Amendments have not yet come into force or been wi cticed in serv. ice, they must be given an opportunity to be tested under the enforceable conditions already described before setting more stringent and arbitrary control levels.

Comprehensive shipboard testing using improved and monitored LOT has now proven the practicability of compliance with both the total oil limit (1/15,000 of the ship's deadweight tonnage) and the concentration rate (60 litres per mile). Exxon is not in favor of universally more stringent requirements and supports the provisions of Regulation 9(1) (including that feature which lessens the permissible discharge level for newly built large tankers to 1/30,000 of the tonnage).

Accidental Discharges The draft Convention preamble has as one of its goals "the minimizing of accidental discharges." Pollution avoidance from accidents is addressed in footnote 33 of draft Regulation 13(2) (double-bottom tankers); Regulations 22-24 (hypothetical oil outflow and tank size); and Regulation 25 (subdivision and stability). These regulations have been reviewed in conjunction with published technical and statistical data on tanker accidents. Exxon has concluded that, while a reasonable degree of tanker subdivision is required for ship safety, the basic premise of preventing accidental oil pollution through ship design features is not technically sound.

When consideration is given to the amount of energy which must be absorbed in large ship accidents, it is abundantly clear that no logical or productive way exists to make tankers collision- or grounding-proof. It can even be shown that features such as double-bottoms or doublesides could, in some instances, endanger the safety or survivability of tankers. Following accidents, such design features could produce a reduction of stability, increased difficulty of salvage or both, thereby endangering the survival of the crew and the entire ship with its cargo.

The Exxon position on avoidance of pollution from accidents is fundamentally oriented to accident prevention and not the mitigation of cargo outflow. In this context, we are opposed to that feature in footnote 33 of Regulation 13(2) which suggests a mandate for the construction of double-bottom tankers. Further, we do not believe Regulation 25 will provide sufficient benefit to warrant its inclusion in the Convention. Lastly, Regulations 22-24 in their present form provide little benefit relative to the cost of compliance. Exxon recommends reconsideration of an earlier proposal which would permit more realistic increase in tank size and hypothetical oil outflow with increases in tanker deadweight. This can be accomplished by amending the formula in Regulation 24(2) to 500 times the cube root of deadweight.

Consistent with the objective of preventing accidents, IMCO has already made significant progress in defining and encouraging the use of traffic separation zones in areas of high traffic density. Exxon supports the continuance of this endeavor and recommends mandatory use of traffic separation zones for areas where the risks are known to be highest. As an extension of this concept, it is felt IMCO should recommend, and where possible mandate, the development and use of harbor approach control systems for traffic entering busy ports. Additionally, IMCO should seriously consider requiring the installation aboard ships of improved navigation and collision avoidance equipment as these types of equipment become operational. Finally, Exxon supports work already started in regard to tightening of licensing and training standards for officers. These are judged to be the most productive steps for achieving a reduction of accidents and the pollution resulting therefrom.

Although none of these accident prevention measures are contained in the current 1973 Convention draft, Exxon proposes that they be considered as a more effective approach to minimizing accidental oil discharges.

A review of recent vessel collision and grounding accident statistics, with emphasis on the polluting incidents, indicates that the majority occur in harbors and their approaches. In these areas traffic density is high and waters are relatively shallow--conditions which clearly increase the probability of collision and grounding accidents. The growing use of larger tankers, which in many cases discharge their cargoes in offshore, deep-water facilities, represents a trend which will cause a continuing reduction in collision and grounding incidents. Exxon be. lieves the need for expensive vessel design features to mitigate pollution from accidents is obviated by this transportation and terminal trend. The preferable alternative to spending for such design features as double-bottoms is the use of capital for the construction of more environmentally sound deep-water terminals.

Conclusion The pollution-abatement recommendations contained in the foregoing position are responsive to the need for reducing operational discharges from tankers and for minimizing pollution caused by vessel accidents. The recommendations provide clear evidence of Exxon's support for pollution abatement by remedial measures which can be realistically attained by the international marine community. They represent a balanced combination of elements for a Convention which will be effective in satisfying marine environmental objectives at a minimum cost in relation to results.


William 0. Gray
Exxon Corporation
New York, New York


for being the most effective single international act ever devised for eventually bringing about effective control and prevention of noxious pollution from ships of all types. It is undoubtedly the most detailed set of pollution prevention standards and measures ever drafted for ships. Because of its great detail, many have already concluded that it will be many years before the new convention can be brought into force. We do not believe this need be or should be the case. We hope that by constructive and cooperative actions by both governments and industry, the 1973 IMCO convention will be effectively brought into force at the earliest practical date.

In order to analyze the above factors, this paper is divided into the following major sections:

The International Convention for the Prevention of Pollution from Ships, 1973, drafted in London under IMCO auspices last fall is undoubtedly the most comprehensive and potentially promising step yet taken to prevent pollution to the seas by ships. While this convention is now open for ratification by nations, its very detailed nature has already caused studies to commence to identify the steps which must be taken to assure its practical and timely implementation .

This paper reviews first the essential provisions of the convention, stressing the technological elements relating to oil tankers. These elements include ships' operational and equipment features, as well as fundamental design changes for new tankers ordered after December 31, 1975. In addition, questions of reception facilities ashore will be considered. The paper will include a status report in regard to each of these matters as of the date of this conference, rather than a recap of the many technical studies already done prior to the IMCO 1973 convention

While Exxon studies on this subject must form the basis of the paper, to the extent possible, activities of various industry groups and governments toward bringing the IMCO 1973 convention effectively into force will be covered as well

The need for a new convention
Principal 1973 convention features
Requirements of the 1973 convention for oil tankers
Progress towards ratification.

As each of these topics is discussed, we will attempt to highlight the specific studies and actions taken by industry, with governments, to foster a realistic and cooperative approach to solving mutual problems in achievable ways.

The need for a new convention

There still are many, both in industry and government, arguing against the need for further pollution regulations. Proponents of the status quo have argued that there are more than enough regulations already. Nevertheless, oil and shipping industry aitics seemingly have an inexhaustible supply of data describing the abuses under present regulations.

In our view, present international conventions and local regulations for prevention of pollution from tanker operations fail for one or more of the following reasons:

Much has already been written about the International Conference on Marine Pollution, 1973, which was concluded on November 2,1973, after four weeks in London. This conference was conducted pursuant to Resolution A 176(VI) of the IMCO (Inter-Governmental Maritime Consultative Organization) Assembly adopted on October 21, 1969. The main conference objective was set out in IMCO Assembly Resolution A 237(VII) as being "the achievement, by 1975 if possible, but certainly by the end of the decade, of the complete elimination of the willful and intentional pollution of the seas by oil and noxious substances other than oil and the minimization of accidental spills."

As this paper is written, one year after the conference, it is our hope to add perspective to that event by a review of the International Convention for the Prevention of Pollution from Ships, 1973. This document - the 1973 IMCO Convention was the principal product of the conference, and its future will largely determine whether or not the conference was successt al. Despite 2-1/2 years of intensive preparatory meetings at IMCO, and conference attendance by more than 600 representatives from 79 nations, six other U.N. specialized agencies, and a dozen nongovernmental organizations, the conference and the convention which it drafted remain essentially unknown to other than actual participants and the marine community directly affected. In short, as U.N-sponsored conferences go, this was not headline material, and many principals, even in the governments most directly concerned, have a vague understanding at best of the significance of the 1973 IMCO conven

(1) The 1962 amendments to the 1954 Pollution Prevention Convention fundamentally permit unlimited discharge of oil out. side of its prohibited zones from all tankers constucted prior to the 1970s. For all tankers, even in the prohibited zones right up to the shore, discharges are permitted at a rate of no greater than 100 ppm (oil in water), and the total quantity is not limited. The 1954 convention as modified by the 1962 amendments represents the only present international agreement on this subject which is in force.

(2) The 1969 amendments to the 1954 convention were intended to rectify the faults of the 1962 amendments by specifying a limitation on total quantity discharged per ballast voyage (1/15,000 d.w.t.), as well as a maximum rate of discharge (60 liters per mile). Both of these provisions would be applicable anywhere on the high seas, and they have been included in the new 1973 convention for all tankers other than new tankers. Nonetheless, despite initial agreement by the IMCO Assembly in 1969 and subsequent ratification by 21 nations controlling over 80% of the world's tanker tonnage, the 1969


Nonetheless, it is our belief, and that of increasing numbers in industry, that this convention, once implemented, has the potential



force compared to previous agreements. Furthermore, the new convention can be amended through a tacit acceptance procedure initiated at regular meetings of per mancnt IMCO bodies without the need of holding future conferences. Thus, it should be possible in the future to quickly change the agreement, making it inuch more responsive to environmental and technological developments.

amendments have not yet wme into force since ratification by at least 32 nations is required to make them international law.

(3) Under the 1962 and 1969 amendments, there is not specified a truly adequate enforcement procedure or regime. Enforcement of alleged high-seas violations is left to the sole discretion of the flag-state administration, and coastal or port states are powerless to act unless violations are actually detected in their territorial waters.

(4) The only oils covered by the 1962 and 1969 amendments are so-called persistent or heavy oils so that aside from a few national regulations which can apply only in territorial waters, there is no present limitation on the discharge of nonpersistent light oil (gasoline, jet fuel, etc.).

(5) Neither the 1962 nor 1969 amendments specify the means or hardware by which discharge standards are to be met.

Other features of particular importance to tanker operations will be brought out as we discuss the specific convention requirements for tankers which are contained in table 1.

Requirements of 1973 convention for oil tankers

During the two years of preparatory studies at IMCO which preceded the convention, five alternative systems were examined for the control and minimization of operational pollution from oil tankers. These included:

Each of these shortcomings has clearly been recognized by both industry and government advocates of the 1973 convention. To a large degree, the 1973 convention, once implemented, will correct these inadequacies. We definitely feel the new convention is needed since the shortcomings under present regulations are, unfortunately, all too evident, not only in the documents themselves, but in a continuing record of abuses under current standards.

Study I-segregated ballast tankers

Study II - membranes in cargo tanks to separate cargo oil from ballast water

Study III -retention of oil on board during ballast voyages, commonly referred to as load on top (LOT)

Study IV-cleaning of cargo tanks for clean ballast at tanker discharge port before sailing

Study V-installation of reception and processing facilities for oily ballast and slops at all tanker loading ports.

Principal convention features

A comprehensive review of the provisions of the new convention was given in an excellent article by Admiral W. M. Benkert, published in Proceedings of the Marine Safety Council, USCG. We have taken the liberty of appending to this paper his table comparing the various provisions of the new convention with the previous 1954 convention and its various amendments. (See table L.) Since Captain Sid Wallace has prepared a companion paper for this conterenæ discussing the new cunvention, particularly in terms of its legal aspects, we will touch only briefly on these. The following key points, however, may be found useful as we discuss the convention further

(1) Although we will be talking only of application to oil tankers, it is important to point out that the convention contains specific regulations for the prevention of pollution from ships of all types, and its coverage extends to all types of pollutants (other noxious liquid substances in bulk, hazardous substances in buik, sewage, and garbage).

(2) For the first time an international convention has been drafted specifying not only permissible discharge standards but also the means by which discharges will be controlled. That is, not only are the objectives to be achieved specified, but also the means and hardware are clearly specified, particularly for tankers.

(3) The methods for enforcing the 1973 convention's provisions for offenses on the high seas are somewhat improved over past international agreements. However, in our view and in that of many in industry, a further strengthening is still needed. Only limited inspection rights are accorded to port states (in which foreign ships call) for alleged high-seas violations. Prosecution rights still remain solely with flag-state administrations. Various recent industry position papers, both before and after the convention, have expressed the hope that through the Third U.N. Law of the Sea Conference, stricter port-state enforcement rights will eventually be agreed upon.

(4) The new convention does contain a very powerful enforcement provision. Contracting states are permitted to deny port entry to foreign vessels (a) which are not in conformance with the convention or (b) which fly the flag of noncontracting states, thus ensuring that they do not receive more favorable treatment than vessels controlled by the convention.

(5) Finally, the new convention contains two extremely important provisions; first, in regard to being brought into force, and secondly, in regard to future amendment of its technical provisions and regulations. As stated earlier, the 1969 amendments have not become international law due to the large number of nations whose ratifications are needed to bring them into force. Recognizing this failure, the present convention will be brought into force 12 months after ratification by only 15 nations who, between them, control 50% of the gross tonnage in the world's merchant fleet. This formula offers the possibility for rapid entry of the convention into

After considerable review at the preparatory IMCO meetings, the concepts of "in-lank" membranes (study II) and cleaning of dirty cargo tanks at discharge ports (study IV) were eliminated from further consideration as prime control measures at the conference itself. Each of these schemes, although theoretically promising, possessed substantial practical drawbacks, including possible adverse safety implications.

The final provisions adopted for control of operational pollution consist of a combination of the remaining three proposals ( segregated ballast tankers, LOT, and reception facilities at tanker loading ports and at repair ports). These provisions, and the interaction between them will now be discussed.

The LOT system for operating ballasted tankers was developed by industry in the early 1960s and has been used since that time by an increasingly large proportion of the world's crude oil tankers with varying degrees of success. LOT fundamentally involves carefully controlled handling of dirty ballast water and tank-washing slops in order to accumulate and retain the maximum amount of oil after gravity settling of this oil out of dirty ballast and wash water. While this operation is sensitive to the nature of the oil to be recovered, the weather encountered on a ballast voyage, and the diligence of a tanker's crew, it has indisputably been shown to be capable of recovering 98% to 99% of the oil remaining in a tanker following discharge of its cargo. In the absence of LOT, the amount of persistent oil that could be discharged to the sea in a typical ballast voyage would approximate between 0.3% and 0.6% of the tanker's d.w.t.-a quantity on the order of 1,000 tons or more for each ballast voyage of a large cude tanker. Properly conducted, LOT permits retention of this oil aboard the tanker at the conclusion of its ballast voyage. A new cargo of crude oil is “loaded on top" of these retained slops for discharge at the conclusion of its next loaded passage.

The problems encountered with LOT include the following:

(1) Since retained slops inevitably contain some sea water, these slops cannot be mixed with a new cargo in product-tanker service, as product contamination would result. Accordingly, LOT has traditionally been used only in crude service where a certain amount of water contamination is generally acceptable.

(2) A certain limited number of refineries have refused to accept aude cargoes containing water-contaminated slops resulting from the use of LOT. In such circumstance, the ballast-voyage tanker operator has no recourse other than to discharge the entirety of his oily slops to the sea prior to loading a new cargo; that is, of course, if there are no adequate slop-reception facilities at the tanker's loading port.

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