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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competencies and with regard for appropriate balance.
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COMMITTEE ON MARINE TRANSPORTATION OF HEAVY OILS
MALCOLM L. SPAULDING, chair,
University of Rhode Island, Narragansett
MALCOLM MacKINNON III,
NAE, MSCL, Alexandria, Virginia
JACQUELINE MICHEL,
Research Planning, Inc., Columbia, South Carolina
R. KEITH MICHEL,
Herbert Engineering, San Francisco, California
JAMES L. O'BRIEN,
O'Brien's Oil Pollution Service, Inc., Gretna, Louisiana
STEVEN L. PALMER,
Florida Department of Environmental Protection, Tallahassee
Laisons
PETER F. BONTADELLI,
California Department of Fish and Game, Sacramento
MICHAEL C. CARTER/DANIEL LEUBECKER,
Maritime Administration
BARBARA DAVIS,
Environmental Protection Agency, Washington, D.C.
JERRY A. GALT,
National Oceanic and Atmospheric Administration, Seattle, Washington
THOMAS HARRISON,
United States Coast Guard, Washington, D.C.
National Research Council Staff
SUSAN GARBINI, Project Director
DONNA HENRY, Project Assistant
CAROL R. ARENBERG, Editor,
Commission on Engineering and Technical Systems
DELPHINE D. GLAZE, Administrative Assistant
MARINE BOARD
JAMES M. COLEMAN,
NAE,
chair,
Louisiana State University, Baton Rouge
JERRY A. ASPLAND, vice chair,
California Maritime Academy, Vallejo
BERNHARD J. ABRAHAMSSON,
University of Wisconsin, Superior
LARRY B. ATKINSON,
Old Dominion University, Norfolk, Virginia
PETER F. BONTADELLI,
California Department of Fish and Game, Sacramento
LILLIAN C. BORRONE,
NAE, Port Authority of New York and New Jersey
BILIANA CICIN-SAIN,
University of Delaware, Newark
SYLVIA A. EARLE,
Deep Ocean Exploration and Research, Oakland, California
BILLY L. EDGE,
Texas A&M University, College Station
JOHN W. FARRINGTON,
Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
MARTHA GRABOWSKI,
LeMoyne College and Rensselaer Polytechnic Institute, Cazenovia, New York
R. KEITH MICHEL,
Herbert Engineering, San Francisco, California
JEROME H. MILGRAM,
NAE, Massachusetts Institute of Technology, Cambridge
JAMES D. MURFF,
Exxon Production Research Company, Houston, Texas
STEVEN T. SCALZO,
Foss Maritime Company, Seattle, Washington
MALCOLM L. SPAULDING,
University of Rhode Island, Narragansett
ROD VULOVIC,
Sea-Land Service, Charlotte, North Carolina
E.G. "SKIP" WARD,
Shell Offshore, Houston, Texas
Staff
PETER JOHNSON, Acting Director
SUSAN GARBINI, Senior Staff Officer
DANA CAINES, Financial Associate
THERESA M. FISHER, Administrative Assistant
DONNA HENRY, Project Assistant
Preface
Background
Maritime accidents that result in oil spills are high on the list of public environmental concerns. These spills are difficult to control and can contaminate the marine environment. When oil is spilled on the sea, it undergoes physical, chemical, and biological changes as it weathers and is degraded by bacteria. Most oil spill cleanup technologies, which have been developed for floating oils and the ensuing emulsions, are not very effective. For most spills, only about 10 to 15 percent of the oil is recovered, and the best recovery rates are probably about 30 percent (OTA, 1990).
Some oils with a specific gravity greater than 1.0 (and some other oils in certain circumstances) may be neutrally buoyant or sink when spilled on water, depending on the salinity of the water. Federal rules governing oil spill contingency plans categorize petroleum cargoes according to their physical properties. Oils with a specific gravity of > 1.0, referred to as Group V oils, include some heavy fuel oils, asphalt products, and very heavy crude oils. Vessels and terminals that handle Group V oils are required to include responses to spills of Group V oils in their facility response plans.
The electric power generation industry often uses Group V oils because some Group V oil products are cheaper and have higher BTU content than other fuel oil products. Among these products are manufactured oils consisting of bitumen, water, and emulsifying agents. The presence of an emulsifying agent in the oil complicates the physical behavior of the oil if it is spilled into the water. Emulsified oils have been shown to sink initially to the level of their specific
gravity and to surface later as the result of chemical changes caused by weathering.
Oils that sink to the bottom or remain suspended in the water column pose risks to certain resources that are not normally affected by floating oils. These resources include fish, shellfish, seagrasses, and other benthic (seabed) and water-column biota. Submerged oil may also cause episodic re-oiling of shorelines.
Although spills of Group V oils have been infrequent, there is some experience in responding to them and in cleaning them up. In most incidents in open water, oil in the water column is unrecoverable, and response operations are largely limited to locating and monitoring its movement. Where there is little or no current flow, suspended oil can sink and pool. In these cases, an effective response can be mounted, and most of the oil on the bottom can be recovered. Effective response (i.e., protecting the nearshore benthic communities) also means removing oil from the shoreline when and if it becomes stranded to keep it from being eroded and sinking in the nearshore tidal areas. Techniques that have been developed and demonstrated for recovering Group V oils following a spill include recovery of accumulations of oil on the seabed and vacuuming oily water for recovery in an oil-water separator. Other mechanical measures have also been investigated.
Origin and Scope of the Study
In the Coast Guard Authorization Act of 1996, the United States Coast Guard (USCG) was directed to assess the risk of spills for oils that may sink or be negatively buoyant, to examine and evaluate existing cleanup technologies, and to identify and appraise technological and financial barriers that could impede a prompt response to such spills. The USCG requested that the National Research Council (NRC) perform these tasks. In response to this request, the NRC established the Committee on the Marine Transportation of Heavy Oils under the auspices of the Marine Board.
The objectives of the study were: (1) to assess threats posed by the marine transportation of Group V oils by characterizing the trade of such oils and, in general terms, the resources at risk; (2) to assess the adequacy of cleanup technologies for spills of Group V oils and recommend research to develop new technologies and techniques, as appropriate; and (3) to identify barriers to effective responses to spills and recommend technological, financial, or management measures that would promote prompt and effective responses to spills of Group V oils. In discussions with the USCG and congressional staff, the committee clarified that the scope of study included the risk of oil spills and the capability of responding to them, although the environmental and health risks of spilled oil are not areas of the focus.
Committee members were selected with expertise in the following areas: the fate and effects of petroleum in water, habitats, and ecosystems; oil-spill response
and cleanup technologies and operations; engineering systems analysis; tank vessel operations and port operations; environmental and regulatory issues; and relevant management and economic issues. Biographies of the committee members are provided in Appendix A.
Early in the committee's deliberations, it became clear that Group V oils, as defined by the USCG (oils with a specific gravity greater than 1.0), did not encompass all of the oils of concern. The drawbacks of using this narrow classification are that some Group V oils remain on the sea surface throughout the early response phase, while some lower density (e.g., Group IV) oils can be dispersed in the water column and sink to the seabed after weathering and interaction with sediments in the water column or after stranding onshore. The committee, therefore, decided to focus on the behavior of oil and use the term "nonfloating oils" as its operational definition. "Nonfloating oils" refers to oils that either initially or after weathering can be found in the water column or on the seabed; this definition includes oils that are suspended in the water column, sink to the seabed, or interact with sediments and are then deposited on the seabed or shoreline. The terms "sunken oils'' or ''submerged oils" are also used to describe oils that behave in this way.
The committee met four times during 1998 to gather information and discuss the issues of concern. At three of the meetings, presentations were made by a wide variety of individuals representing organizations in the transportation, spill response, environmental, scientific, and regulatory communities. A workshop was held in conjunction with the committee's second meeting to obtain information and to facilitate discussions of the issues. Leading experts in the marine transportation and spill response communities with expertise in the transport and response to spills of heavy or nonfloating oils participated in the workshop and panel discussions. Participants in the meetings and workshop are listed in Appendix B.
The committee's report is divided into five chapters. Chapter 1 focuses on the risk of spills of nonfloating oils and describes the traffic and trading patterns and recent history of heavy-oil spills, based on an analysis of available databases.
Chapter 2 describes the behavioral models for spills of nonfloating oils that can further an understanding of the fate and impact of these oils and be used to identify the resources at risk. This chapter also includes a comparative assessment of the environmental risks from spills of floating and nonfloating oils. Chapter 3 summarizes the technologies and techniques available for responding to spills of nonfloating oils. Subsections focus on modeling and information systems, spill tracking and mapping techniques, and containment and removal systems. Chapter 4 presents a discussion of the managerial, technological, and financial barriers to effective spill response. Chapter 5 presents the committee's findings, conclusions, and recommendations.
Acknowledgments
The committee wishes to thank the many individuals who contributed their time and effort to this project by presenting material at committee meetings and workshops. Representatives of federal and state agencies, as well as private companies, provided invaluable assistance to the committee and the Marine Board staff.
This report has been reviewed by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the NRC’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the authors and the NRC in making the published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The content of the review comments and draft manuscript remains confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their participation in the review of this report:
John W. Farrington, Woods Hole Oceanographic Institution
Mervin F. Fingas, Environment Canada
Michael Herz, Marine Environmental Consultant
Donald S. Jensen, Jensen & Associates
Jerome H. Milgram, Massachusetts Institute of Technology
David Page, Bowdoin College
John Roberts, Coastal Towing
While the individuals listed above have provided many constructive comments and suggestions, responsibility for the final content of this report rests solely with the authoring committee and the NRC.
Boxes, Figures, and Tables
Boxes
2-1 |
The Nestucca Spill |
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2-2 |
The Morris J. Berman Spill |
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2-3 |
The Sansinena Spill |
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3-1 |
Oil-Spill Model |
Figures
1-1 |
Import/export and domestic movements of all crude oil and petroleum products in metric tons during calendar year 1996 |
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1-2 |
Import/export and domestic movement of crude oil and petroleum products in metric ton-miles during calendar year 1996 |
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1-3 |
Movements of petroleum by commodity in metric ton-miles during calendar years 1991 to 1996 |
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1-4 |
Movements of petroleum by tanker and tank barge in metric ton-miles during calendar years 1991 through 1996 |
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1-5 |
Volume of oil spilled from vessels in U.S. waters (1973 to 1996) |
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1-6 |
Geographical distribution of heavy-oil spills of 20 barrels or more from vessels in U.S. waters (1991–1996) |
2-1 |
The relationship between water density and salinity at a temperature of 15°C |
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2-2 |
Behavior of spilled nonfloating oils |
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2-3a |
Oil-to-water density < 1.0; low sand interaction; majority of oil floats |
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2-3b |
Oil-to-water density < 1.0; oil initially floats but sinks after stranding |
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2-3c |
Oil-to-water density < 1.0; oil initially floats but sinks after mixing with sand in water |
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2-3d |
Oil-to-water density > 1.0; low currents; majority of oil sinks |
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2-3e |
Oil-to-water density > 1.0; high currents; oil disperses in water column |
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2-4a |
Emulsified oil in freshwater; low currents; oil sinks |
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2-4b |
Emulsified oil in freshwater; high currents; oil disperses and eventually sinks |
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2-4c |
Emulsified oil in saltwater; high currents; oil initially disperses then coalesces into tarry slicks |
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3-1 |
Decision tree based on oil density and water depth |
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3-2 |
Decision tree for containment options for sunken oil |
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3-3 |
Decision tree for recovery options for sunken oil |
Tables
1-1 |
Movements of Petroleum by Tanker and Tank Barge during Calendar Years 1991 through 1996 |
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1-2 |
Oil Spills of 20 Barrels or More in U.S. Waters by Origin (1991 to 1996) |
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1-3 |
Heavy-Oil Spills of 20 Barrels or More in U.S. Waters by Origin (1991 to 1996) |
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1-4 |
Spill Rates for All Petroleum Cargoes in U.S. waters (1991 to 1996) |
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1-5 |
Spill Rates for Heavy Oil in U.S. Waters (1991 to 1996) |
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2-1 |
Relative Changes in the Resources at Risk from Spills of Nonfloating Oils Compared to Floating Oils |
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3-1 |
Options for Tracking Oil Suspended in the Water Column |
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3-2 |
Options for Mapping Oil Deposited on the Seabed |
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3-3 |
Options for Containing Oil Suspended in the Water Column |
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3-4 |
Options for Recovering Oil Deposited on the Seabed |