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In a report of comprehensive hearings issued by the Senate Committee on Commerce on March 28, 1972 there is the statement: "Double Bottoms. Perhaps the clearest instance of a standard presented at the committee's hearings that must be seriously considered, is that of double bottoms. Groundings, such as that of the Torrey Canyon, can be serious causes of catastrophic oil spills."

There seems to be the clear implication here that the Senate Commerce Committee felt double bottoms might be effective in an accident as extreme as the Torrey Canyon disaster. Yet in hearings before the House Committee on Merchant Marine and Fisheries on June 6, 1973 a Coast Guard witness stated categorically that the double bottom construction would not have saved the Torrey Canyon. Their testimony generally supports industry views that it would be of little use in what Coast Guard described as "high energy" groundings—that is, the high speed, serious accidents. As previously noted, it is the small number of serious accidents which historically have produced 60% of grounding spillage.

Turning to the question of additional cost so often cited as the basis for objections to fitting double bottoms, the 1972 Senate Commerce Committee hearings concluded that the additional cost of double bottom construction would be approximately 4% (but) the Committee also received somewhat higher estimates." The Committee went on further to state "even the highest of these estimates would be a minuscule factor in terms of petroleum cost because of the tiny proportion of total petroleum cost that is represented by tanker transport."

These values may be contrasted with estimates supplied by the Coast Guard for the House Merchant Marine and Fisheries hearings a year later in which a percent cost increase of 834% was presented. Furthermore the House Committee, referring to long haul crude tanker traffic, estimated transportation cost at "about 20% of the total cost as a minimum of landed product."

While AIMS believes the higher Coast Guard estimates to be

more nearly correct, we also believe that capital increments of this order would not represent an unreasonable burden for industry or consumersif the double bottom could assuredly do what its advocates feel it could. Faced, however, with the prospect of little improvement at best, the additional cost and additional steel requirements on the order of 6,000 tons for each double bottom tanker of 200,000-300,000 tons, represent a wasteful misuse of capital and steel at a time of pressing shortages of each.

Finally, it is important to consider how marine regulatory experts outside of the United States view this proposal from an environmental protection viewpoint. On his return from the 1973 IMCO Marine Pollution Conference the leader of the U.S. delegation, the Hon. Russell Train, appeared before hearings of the Senate Committee on Commerce held on November 14, 1973. In reference to questions about the IMCO decision not to require double bottoms, Mr. Train said: "While I was not present in the technical committee where most of this discussion took place, I think it is fair to say that there is a very strong difference of opinion with the United States on the subject of double bottoms. Not simply from the standpoint of the additional costs involved, but I gathered real differences of opinion as to effectiveness of double bottoms as a means for reducing accidental discharges.

"There were those who feel, for example, that with double bottoms if a ship goes on a reef and the double bottom is breached and fills with water, even though this is not mixing with oil and there may be no discharge of oil at that point, the ship will settle more positively, if that is the phrase, upon the reef and be that much more difficult to get off.


may well be that the use of the double bottom in such cases could be a detriment rather than an advantage in terms of protecting the seas."

In our view Mr. Train summarized very well the principal points made by the world's marine regulatory experts. At the IMCO deliberations U.S. proposals for mandatory double bottoms were put to a vote on two occasions. They were both defeated, first by a vote of 22 to 9 as a requirement for larger tankers, and later by a vote of 21 to 5 for the smaller tankers.

Summary The preceding discussion covers generally all significant arguments made both for and against a requirement for double bottoms in tankers. It will never be possible to absolutely prove whether or not this construction would provide at least some measure of protection or whether it would turn out to be a step backwards in preventing oil pollution of the seas. The preponderance of actual evidence and technical information strongly suggests that double bottoms would be of no value whatsoever in major grounding accidents which though fortunately small in number cause the larger share of oil spillage from groundings.

Though not discussed herein, it seems clear that other measures now receiving serious consideration can definitely bring about a positive reduction in both grounding and collision accidents in the most sensitive coastal areas, and be applicable to all tankers, not just new ones.

Chief among these measures with high potential for preventing accidents are: > Harbor traffic control using shore radar and positive communica

tions with all ships.

> Better ship navigational equipment for position fixing and com


> Improved training programs for personnel.

The potential for preventing accidents by such measures should be obvious, but has only recently been recognized in the United States. AIMS supports steps in this direction now being taken by our Coast Guard and looks for them to be effective in the near future. Such steps based on sound technical and human engineering should be pursued as a matter of high priority.

July 1974


Exxon Corporation is committed to continuing its efforts to make its operations and its products compatible with a clean environment. It is Exxon's objective to work with outside groups to develop a consensus on those environmental qualities which are both desirable and attainable. It is also Exxon's objective to work with governmental groups to foster and encourage the development of regulations needed to achieve reasonable standards of environmental quality.

In accord with these broad objectives, Exxon has taken a position on sea pollution abatement that describes techniques and policies that will do most to reduce oil discharges from tankers if adopted by fleets worldwide. The position takes into account two main needs: Reduction must be scheduled in a manner and on a scale which minimizes ecological and aesthetic damage to the environment. Reduction must also be undertaken in a practical manner consistent with the character and capability of the marine tanker industry.

The purpose of this paper is to set forth Exxon's position and to outline specific recommendations for implementing-through an international Convention-a program for the reduction of oil discharges from tankers. A comprehensive and up-to-date view of the tanker industry in relation to marine environmental concerns is given in the attached brochure, Safer Tankers and Cleaner Seas. This background paper highlights five key aspects of the ocean pollution problem: the sources of oil pollution; scope; current knowledge of effects on the marine environment; marine industry control efforts; and governmental abatement activities. Exxon's position is derived from this view of the problem.

will depend heavily on several general considerations.

Exxon believes the Convention must respond to public and governmental pressures to improve the conduct and regulation of all marine industry operations. At the same time, it must take into account the recognized lack of scientific information on the capacity of the seas to assimilate various discharges, and it must consider the benefits of various corrective actions in relation to their costs.

Operational discharges, characterized by many governments as intentional, are defined as oil or oily mixtures discharged during normal vessel operations. These would include dirty ballast (i.e., ballast from a tank which has not been cleaned), tank-washings, cargo sediment, engineroom bilge and fuel or lube sediments from purifying systems. However, accidents which result in oil spills are an integral part of the pollution problem. Improved measures to prevent accidents-e.g., better equipment, procedures, training-should be considered during Convention development, whether or not these measures are specifically incorporated in the Convention.

Because operational and accidental discharges result from so many different situations, there is need for a Convention with a balance of remedial measures. Despite the attractiveness of a simple "one-solution" approach to future oil discharge regulations, Exxon believes that a variety of anti-pollution measures are needed to deal effectively with the different types of ships and trades. A balanced combination of measures will not only be more realistic and effective, but less costly in relation to results.

A balance of anti-pollution measures will prob. ably be more widely acceptable and enforced. Nations differ greatly in the nature of their coastal concerns and their capability for under. taking enforcement programs. Exxon feels it is essential to have a realistic Convention which encourages meaningful national legislation with enforceable penalties for failure to comply.

Solutions for oil tanker discharge problems are costly and are additive to the massive capital outlay requirements already facing the petroleum industry to meet other environmental requirements and rapid growth. These outlays are also of great significance to some of the nations involved. Because such expenditures are so crit

Marine Pollution Convention

General Considerations

Exxon's basic, long-term objectives are the minimization of operational discharge of oil and other harmful substances, and the reduction of accidental release of such substances. A new international Convention will be necessary in order to approach or attain those objectives. Rapid Convention adoption and implementation


ical to achieving an acceptable and effective pollution-avoidance program, and because certain of the control techniques will produce identical results, the Convention must guard against requirements which would result in duplication.

Finally, Exxon sees significant advantage in a Convention which provides rapid ratification procedures. Such procedures would help ensure earlier attainment of environmental objectives, promote the establishment of national priorities and aid planning by the marine industry.

Assessment of Convention Elements Taking into account the broad considerations covered above, we have reviewed the proposed features in the final draft Convention with the objective of defining the most effective combination of requirements for a new Convention. Our review has attempted to identify those elements most likely to guarantee progress in the areas of: controlling operational pollution; ensuring compliance with Convention provisions; and minimizing accidental oil discharges from tankers. While we fully recognize the need for Convention provisions for ships other than tankers, and pollutants other than oil, our analysis is concerned only with tanker-related pollution abatement.

To achieve reductions in operational pollution, Regulation 11 of Annex I contains three basic control measures: optional and/or mandatory provisions for retention of oil on board (loadon-top); segregated-ballast tankers; and shore reception facilities-either singly or in some yet. to-be-defined combination. When assessing each of these three measures, certain characteristics of international oil movements must be taken into account.

Energy growth trends to the end of the century indicate a near doubling each decade of marine oil movements, with a preponderance of seaborne movements of crude oil relative to refined products. In the crude oil trades, the principal sources of operational discharges are dirty ballast and tank washings for clean ballast. In the product trades, tank washings are a more important consideration than dirty ballast be. cause the washing of tanks is carried on more frequently. Ships in both trades require cleaning of all tanks prior to entering repair ports. Lastly, the loading areas for crude oil are increasingly moving to offshore sites, and they may be expected to change both in volume throughput and location with new oil finds and shifts to larger tankers.

With these basic features as background, there follows an analysis for the three basic pollution-control measures.

Load-on-Top Of the three measures, retention of oil residues on board, or load-on-top (LOT), is the only one already being practiced to a significant de gree. It is also the only one which, if sufficiently improved, will provide immediate further abatement of operational oil discharges. While LOT has already produced substantial reductions, we do feel a significant potential exists for further reductions using this technique. LOT can be improved by more detailed instructions for the use of this technique, on-board monitoring instrumentation of oil discharges, and a pro gram of in-port inspection for compliance.

New guidelines for the conduct of load-on-top have been developed by industry (OCIMF and ICS) for consideration by IMCO. It is our expectation that these instructions will form the basis for the draft requirements for a manual in Regulation 15(3)(f).

With regard to monitoring instrumentation, the equipment requirements (exclusive of automatic control features) of Regulations 15, 3(d) and 3(e) should be achievable at about middecade with instruments already under development and partially in use. Reasonable performance criteria for the monitoring equipment are also essential to the Convention. Lastly, to assure the fullest possible compliance with load-on-top, the inspection provisions of Regulation 4 should be supplemented by specific requirements for loading port inspection of retained slops on all crude tankers.

A Convention embodying these features would make the load-on-top system an effective measure for attaining the necessary operational discharge reductions from existing crude tankers throughout their useful lives.

Technological progress in the instrumentation field has not advanced to the state where automatic monitoring, recording and effluent control of oily discharges are possible. If such an automated system or so-called "black box" device is developed, the LOT procedure could become the primary long-term measure for pollution avoidance from all crude tankers. In the absence of such equipment, other primary pollution abatement measures for new-built tankers appear warranted.

Segregated-Ballast Tankers Exxon believes that a change in tanker design should be undertaken to further improve pollution controls over a period of time. The most logical way to effect such evolutionary improvement is to require, through Convention mandate, that all newly built crude tankers ordered and delivered later in this decade have segregatedballast tanks.

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