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Spills & Accidental Releases

Analysis of US Oil Spillage

Total petroleum industry spillage has decreased consistently over the last 40 years. Seventy-seven percent less oil is spilling since the 1970s and 54% less since the previous decade. The analyses in this report examine oil spillage and other oil inputs into U.S. waters from all angles; from the spills of greatest public concern, those from the oil industry tankers and offshore production platforms, to the spills attributable to public consumers.

For details, see the complete report: Analysis of U.S. Oil Spillage

Spill Prevention and Response Website

Spill Prevention and Response

Every day, a network of tanker ships, pipelines and trucks safely delivers millions of gallons of oil and natural gas to fuel the American economy. Spill Prevention and Response is an interactive website that explores how new technologies and better training yield continual improvements as we strive to conserve valuable energy resources and protect our nation's health and environment through spill prevention. And, when spills occur, the United States employs world-leading preparedness planning and response capabilities to minimize harm to the environment.

Preventing Spills

The U.S. oil and natural gas industry supplies more than 65 percent of America’s energy. Bringing important commodities like this to our homes, businesses, schools, hospitals, and the corner gasoline stations involves some risk that oil will accidentally spill. Therefore, industry has made a commitment to meeting the nation's energy needs while maintaining safe and environmentally sound operations. This requires preparedness and continuous improvement in every phase of operations where oil is produced, transported, stored or marketed.

And these prevention efforts are bearing fruit. As Captain James D. Spitzer, chief of the U.S. Coast Guard’s Office of Investigations, stated in a letter for the Pollution Incident Compendium: 1973-1997: "By nearly every measure, the volume of spills in U.S. waters has been on a steady downward trend since 1973."

API's Oil Spills in Navigable Waters report confirms this trend. The report uses data from the U.S. Coast Guard and U.S. Environmental Protection Agency, and is an important yardstick in measuring the industry’s progress in protecting the environment. The total volume of oil spilled in the U.S. has remained below 7,000 barrels approximately annually from 1991 – 1999. Based on data from the U.S. Coast Guard, less than 200 barrels (about 8,400 gallons) out of over 3.2 billion barrels of oil delivered by tanker to the U.S. were spilled in 1999. Click to download API's Oil Spills in Navigable Waters report.

Every segment of the oil and natural gas industry has contributed to this progress. Exploration and production facilities use advanced materials and techniques, with multiple back-up safety systems. Pipelines employ computers, electromagnetic instruments, and ultrasonic devices to detect weak spots so they can be repaired before a leak develops. Marine terminals and vessels are being designed differently. Tankers, for example, are being built with double hulls. And storage tanks are constructed of special materials to withstand corrosion. Prevention, however, is not just the job of industry; you play an important role in preventing oil spills, too!



Minimizing oil spills begins with preventing spills in theirs place. Every facility that drills, produces, refines, handles, processes, and/or stores oil has developed a spill prevention, control, and countermeasure (SPCC) plan, documenting that facility’s procedures and equipment for spill prevention. Equipment for spill prevention includes dikes, terms, or other forms of secondary containment installed around tanks and other processing vessels, to retain oil in the event of a release. Spill prevention procedures include tank integrity testing and leak testing to ensure that oil storage and process vessels are in sound operating condition.

Minimizing oil spill impacts on the environment, wildlife and affected communities requires rapid, coordinated responses from the responsible company and appropriate federal, state and local agencies. In the United States, the National Oil and Hazardous Substances Contingency Plan sets goals and assigns responsibilities for managing oil spills.

Each tanker, facility, platform and pipeline develops a plan that identifies the personnel, equipment and materials it needs to deal with a spill. It includes information about storage capacity, environmentally and economically sensitive areas, personnel training, practice drills and a "worst case" scenario. These plans are tested regularly to maximize the use of new technology and to sharpen personnel response skills.

Regional contingency plans identify federal and state concerns. Area contingency plans provide an opportunity for more localized planning and preparations by government and industry.

Oil transportation companies in the U.S. have developed oil spill response co-ops known as Oil Spill Removal Organizations (OSROs). These organizations, on contract with oil companies, provide equipment, personnel, and the skills needed to respond to an oil spill. For example, in 1990, some companies that ship oil in and out of American waters formed the Marine Spill Response Corporation (MSRC). MSRC’s fleet of 16 vessels, each 210 feet in length, is distributed among 16 staging sites in U.S. coastal waters, Hawaii and the Virgin Islands. In addition to MSRC, hundreds of smaller, locally operated OSROs are located throughout the country.

In 1991, API initiated the PetroAssist network, in which 38 member companies participated. Today, PetroAssist enables companies to access specialized expertise quickly and set up necessary legal agreements in advance. Thus, it provides an additional industry-wide safety net.

Recent Advances

Recent Advances

The oil industry has joined with government, universities, and other groups in the United States to conduct research and share information about advances in spill prevention and response.

State-of-the-art navigation systems help reduce the risk of accidents and oil spills in U.S. waters. Components include navigational charts, shoreline mapping, global satellite positioning, port navigation, and forecasting water levels and ocean currents.

Computer-aided detection devices have been developed to monitor how vessels react to stress. For example, a stress-monitoring system for vessels determines how hard waves hit the hull, allowing the crew to take corrective action to reduce structural stress. Some of these systems monitor stresses during normal vessel operations, cargo-transferring procedures, and during severe weather conditions.

Risk assessment processes have helped identify the need for new features on vessels, including: improved steering systems; improved radar detection systems; electronic chart displays; satellite and radio communication; new vessel identification systems such as transponders; and computer monitoring of engine, cargo and hull operations.

Industry, government and environmental experts exchange information about spill prevention, response and cleanup at the biennial International Oil Spill Conference. The published proceedings are critical references for people in this line of work. Beginning with the March 1999 conference, meeting proceedings are available on CD-ROM.

Improved countermeasures, including dispersants, surface washing agents, surface collecting agents, bioremediation agents and burning agents, have been developed and tested extensively. Industry laboratories have developed dispersants that are more effective in treating heavy crude oil over longer periods of time. An oil-weathering model enables oil spill personnel to determine the most opportune times to use dispersants.

The Petroleum Environmental Research Forum, an industry forum for companies to jointly sponsor research, has over the years, conducted research on biosurfactants and solidifiers.

API has sponsored experiments that examine the effects of in-situ (on-site) oil burning on wetland and upland habitat restoration, and researched factors that influence successful burns.

The U.S. Bureau of Ocean Energy Management, Regulation and Enforcement is testing prototype booms that contain and recover more oil faster. It is also striving to determine the thickness of spills with airborne sensors and remote-sensing devices.

API, in conjunction with several other sponsors, has funded research on tests to evaluate toxicity levels after an oil spill. The research examines toxicity levels at different water depths and under various climatic factors.

Low toxicity cleaning agents have been developed to clean shorelines without damaging them. Research conducted at Louisiana State University documents success in cleaning environmentally sensitive vegetation such as mangroves.


When a spill occurs in U.S. waters, the responsible company and the Coast Guard’s National Response Center notify the federal on-scene response coordinator and state officials. The responsible company then activates its response plan, and the National Response Center ensures that the responsible company is properly carrying out the activities in the plan. The federal on-scene response coordinator may also provide resources if it is determined that more are required or the responsible company is not responding adequately. If the spill is large, the U.S. Department of Commerce and the Department of Interior may be contacted for additional assistance.

Major spills, particularly those that occur close to shore, may affect fish, birds and aquatic mammals, as well as vegetation. Accordingly, the response team must include veterinarians, marine biologists, zoologists, botanists and others with specialized expertise.

A spill in the open ocean may have minimal environmental effects since the oil naturally dissipates and disperses. A spill that washes ashore is another matter. No spill cleanup method is a cure-all. Response techniques vary with each individual spill, and can include chemical or mechanical methods. Sometimes natural degradation is the best method of recovery. With the approval of the federal on-scene coordinator, chemical cleaning or dispersal agents can be employed for cleanup. Industry research in this area is continuing to improve the effectiveness of these agents on environmentally sensitive ecosystems.

Cleanup Tools

Generally, the strategy for cleaning up a spill begins with localizing the spill, using a variety of booms. Booms can be used in several ways: containment booms keep the oil from spreading; collection booms hold the oil near the ship, pier or terminal; deflection booms steer the oil towards collection areas and away from sensitive areas; and protection booms create barriers that keep oil from affecting sensitive areas. Booms work best in calm waters. Their effectiveness decreases as wave heights and currents increase.

Other chemical countermeasures are used in various ways. Herding agents push or compress surface slicks while emulsion-treating agents impede the formation of, or break down, emulsions of oil and water.

In-Situ burning entails corralling and igniting oil contained by a fire-resistant boom. In ideal circumstances, this technique removes 90-95 percent of the oil on the surface of water, but precautions must be taken to protect workers and surrounding areas from the fire and smoke. API has developed two downloadable publications to assist in the use of burning as a method of mitigation:

Bioremediation of oil on the shoreline uses naturally-occurring bacteria to "eat" oil. Fertilization of this bacteria increases the rate of natural degradation three to four times without harming plants and wildlife. Over the years, extensive research has shown that bioremediation can be an effective cleanup technique for environmentally sensitive areas. In recent years, the U.S. Environmental Protection Agency has determined that bioremediation is a safe and effective oil removal option.

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