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News from the National Academies

Date: Nov. 6, 1997
Contacts: Molly Galvin, Media Relations Associate
Kristen Nye, Media Relations Assistant
(202) 334-2138; Internet <>


Publication Announcement

Double-Hull Vessels Could Significantly Reduce Oil Spills,
But New Design Standards Are Needed

After the Exxon Valdez ran aground in Prince William Sound, spilling more than 11 million gallons of oil into Alaska waters, the Oil Pollution Act of 1990 was enacted. Because of the law -- and the international maritime regulations that followed -- nearly all vessels used to transport oil will have double hulls by the year 2020, to help protect against spills caused by punctures. Such events cause some 70 percent of maritime oil disasters.

If properly designed, double-hull tankers and barges can significantly lower the risk of large oil spills and offer more protection to the marine environment, says a new report by a committee of the National Research Council. The congressionally requested report is a follow-up to a 1991 Research Council report on tanker designs.

The U.S. Coast Guard should quickly take the lead in developing design standards aimed at ensuring that all double-hull vessels will prevent oil leaks and operate safely, the committee said. Some of the new ships with double-hull designs -- particularly those without a center bulkhead partition -- will not protect against spills as thoroughly as other double-hull designs. They also are not as stable during loading and unloading. New design standards should ensure stability and greater protection from oil leakage.

About 10 percent of oil-transporting vessels had double hulls as of 1994, and many new ones will enter service within the next few years as the industry complies with U.S. and international requirements. Replacing all single-hull tankers with correctly designed double-hull vessels could prevent a great number of spills attributed to collisions and groundings, the report says, and reduce by as much as two-thirds the total volume of oil spilled by such accidents.

In addition, the Coast Guard should develop a surveillance program to monitor the physical condition, maintenance, and operational procedures of older, single-hull vessels that are still permitted in U.S. waters, the committee said. An exemption to U.S. law until the year 2015 allows single-hull vessels with less than 30 years' service to use deep-water ports and offshore areas designated for transferring cargo from vessel to vessel. Other nations such as Japan and Korea are preventing older vessels from calling at their ports, which may increase the number of older tankers that use U.S. areas under the exemption.

The impact of the double-hull requirement on the U.S. domestic shipping industry should be assessed further, the committee said. An independent panel should be appointed to examine policy options that would ensure that enough U.S.-built vessels will be available when needed. Under existing law, vessels that transport oil between any two points in the United States must be built and registered in the United States, and they must be owned and operated by U.S. citizens. Many industry experts have observed that operators may have to replace single-hull vessels in the domestic fleet before the end of their service lives. In addition, uncertainty about future demand in the Alaskan crude oil and coastal products trades may discourage shippers from investing in new vessels.

The Coast Guard needs to develop better data-gathering and analysis techniques to evaluate the impact of double-hull requirements in the future, the committee added. Although oil spills in U.S. waters declined between 1990 and 1995, the drop is probably not because of the double-hull requirements, which are just beginning to take effect. The decline may have resulted from other factors, such as new policies and greater emphasis within the maritime community on protecting the environment.

The study was funded by the U.S. Coast Guard. Copies of Double-Hull Tanker Legislation: An Assessment of the Oil Pollution Act of 1990 will be available in December from the National Academy Press for $34.00 (prepaid) plus shipping charges of $4.00 for the first copy and $.50 for each additional copy; tel. (202) 334-3313 or 1-800-624-6242. Reporters may obtain pre-publication copies from the Office of News and Public Information (contacts listed above).

Commission on Engineering and Technical Systems
Marine Board

Committee on Oil Pollution Act of 1990 (Section 4115)
Implementation Review

        Douglas C. Wolcott (chair)
        Former President
        Chevron Shipping Co.
        Ross, Calif.

        Peter Bontadelli (vice chair)
        Administrator of the Office of Oil Spill Prevention and Response
        California Department of Fish and Game

        Lars Carlsson
        Concordia Maritime AB
        Göteborg, Sweden

        William R. Finger
        ProxPro Inc.
        Friendswood, Texas

        Ran Hettena
        Maritime Overseas Corp.
        New York City

        John W. Hutchinson (1,2)
        Gordon McKay Professor of Applied Mechanics
        Harvard University
        Cambridge, Mass.

        Sally Ann Lentz
        Co-Executive Director and General Counsel
        Ocean Advocates
        Columbia, Md.

        Donald Liu
        Senior Vice President for Technology
        American Bureau of Shipping
        New York City

        Dimitri A. Manthos
        Admanthos Shipping Agency Inc.
        Stamford, Conn.

        Henry Marcus
        Professor of Marine Systems
        Massachusetts Institute of Technology

        Keith Michel
        Herbert Engineering Corp.
        San Francisco

        John H. Robinson
        Santa Barbara, Calif.

        Ann Rothe
        Executive Director
        Trustees for Alaska

        David G. St. Amand
        President and Founder
        Navigistics Consulting
        Boxborough, Mass.

        Kirsi K. Tikka
        Associate Professor
        Webb Institute
        Glen Cove, N.Y.


        Jill Wilson
        Study Director

        (1) Member, National Academy of Sciences
        (2) Member, National Academy of Engineering