This glossary explains some terms found on the Council’s website. Definitions may vary depending on how the term is used elsewhere.

Activated Carbon

Highly absorbent from of carbon used to remove odors and toxic substances from liquid or gaseous emissions. In waste treatment it is used to remove dissolved organic matter from waste water.


A process which promotes biological degradation of organic water. The process may be passive (as when waste is exposed to air) or active (as when a mixing or bubbling device introduces the air).

Air Pollution

Presence of contaminant or pollutant substances in the air that do not disperse properly and interfere with human health or welfare, or produce other harmful environmental effects.

Ballast Water

Water carried in vessel tanks for stability.

  • dirty ballast: ballast water that contains residual oil. When seawater is introduced into empty cargo tanks, residual oil mixes with the water and requires special handling at sea or treatment at a specialized facility before being discharged into the sea. Dirty ballast consists of seawater contaminated with approximately 1% crude oil.
  • clean ballast: ballast water that is essentially free from oil. Does not exceed 15 ppm total recoverable oil and grease (TROG) and does not exceed 15 ppb benzene, toluene, ethylbenzene, and xylene (BTEX).
  • segregated ballast: ballast water that is in tanks designed and used exclusively for that purpose.

Benthic Region

Bottom layer of a body of water.

Biological Treatment

Treatment technology that uses bacteria to consume waste. This treatment breaks down organic materials.


A floating barrier that extends above and below the water’s surface and is designed to prevent the passage of or contain oil floating on water (also called containment boom).


Contingency plan—an action plan with guidelines for what to do in case of an oil spill.

Command Post

Facility located at a safe distance upwind from an accident site, where the on-scene coordinator, responders, and technical representatives can make response decisions, deploy manpower and equipment, maintain liaison with news media, and handle communications.

Crude Oil

Petroleum in its natural state prior to any refining process. Main elements are hydrogen and carbon.

Current Buster

Oil spill containment device capable of collecting, containing, and separating oil at tow speeds and currents up to five knots.


Process by which a chemical is reduced to a less complex form.


Process by which one liquid is dispersed into another in the form of small droplets.

Entrapment Booming

Setting boom to guide oil into a confined area to prevent it from reaching another area.

Environmental Assessment

Written environmental analysis that is prepared pursuant to the National Environmental Policy Act to determine whether a federal action would significantly affect the environment and thus require preparation of a more detailed environmental impact statement.

Environmental Impact Statement

Document required of federal agencies by the National Environmental Policy Act for major projects or legislative proposals significantly affecting the environment. A tool for decision making, it describes the positive and negative effects of the undertaking and lists alternative actions.

Exclusion Booming

Placing boom to prevent oil from entering a specific area, such as a small bay.

Geographic Response Strategies

(GRS) Oil spill response plans tailored to protect a specific environmentally sensitive area from impacts following an oil spill.


Organic chemical compound composed mainly of carbon and hydrogen. Hydrocarbons are the main constituents of crude oils.

In-situ Burning

An oil spill clean up technique in which oil is burned directly where it spilled.

J Configuration

Formation for holding boom in the shape of a “J”.

Non-Indigenous Species

A species that is non-native (or alien) to the ecosystem under consideration.


Polynuclear aromatic hydrocarbon. PAHs are the most common smaller and more volatile compounds found in oil.


A state of becoming more poisonous when exposed to ultraviolet light.

Places of Refuge

A safe refuge (such as a protected bay) for leaking or disabled vessels.

Regional Stakeholder Committee

A group convened as part of a spill response to share their knowledge of the local context with the response Command and to create a bridge between the response and their communities — whether municipalities or villages, Tribes, or stakeholder groups.

What is the RSC?

Response Gap Analysis

A response gap occurs when oil can be transported in weather conditions not feasible for executing a successful oil spill response.

More: Oil Spill Response Gap


When oil that’s been broken apart by a dispersant re-coagulates and pops back to the water surface.

Risk Assessment

Qualitative and quantitative evaluation performed in an effort to define the risk posed to human health and/or the environment by the presence or potential presence and/or use of specific pollutants.


A piece of equipment that removes floating oil from water.

Tanker of Opportunity

A tanker that is in transit and is the closest and most available for storage use in the event of a spill.

Tanker Vapor Recovery System

A system installed on the berths at the Alyeska terminal that captures hazardous air pollutants from tanker loading operations. Vapors are incinerated or are burned in a power generation boiler.

Technological Disaster

Catastrophic event caused by humans that results in the toxic contamination of the environment.

U Configuration

Formation for holding boom in the shape of a “U”.

Wave Tank

A specialized tank that simulates wave action, used for testing oil spill clean-up methods.

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