Council updates position on dispersant use during an oil spill

Prevention and mechanical recovery should remain primary options

A vessel sprays water as practice for applying dispersants during an oil spill drill.
A vessel sprays water as practice for applying dispersants during an oil spill drill.

The Council’s Board of Directors has updated the organization’s position on use of chemical dispersants in the event of an oil spill in the Prince William Sound and the Exxon Valdez oil spill region. The updated position states that dispersants should not be used on Alaska North Slope crude oil spills in the waters of our region.

Chemical dispersants are substances applied to floating oil slicks that break the oil into smaller droplets that disperse into the water column.

The Council has long endorsed mechanical recovery as the primary tool to clean up an oil spill. Unlike dispersant use, mechanical recovery with booms and skimmers removes oil from the water. Conditions in Prince William Sound often limit the feasibility of dispersant application and dispersants have not been demonstrated to be effective in marine environments with similar temperatures and salinity levels to those found in the Sound. Uncertainty exists over the toxicity caused by adding chemical dispersants to an oil slick and the long-term effects of dispersants application are not well understood. The known harms and potential risks caused by dispersants, in addition to a lack of proven effectiveness and safety, preclude the Council from supporting dispersants.

Oil spill prevention remains the Council’s top priority because once oil is spilled there will always be adverse impacts to human health and the environment. In the event of an oil spill in our region, mechanical recovery and containment of oil spilled at sea should remain the primary response method. The Council also recommends that oil spill response research and development should focus on enhancing and improving mechanical recovery technologies and methods.

The Council’s previous position on dispersant use was adopted in 2006, after years of promoting research and testing to increase knowledge about dispersants and the environmental consequences of their use. In the intervening years, the Council has continued to track developments and analyze peer reviewed scientific literature from around the world regarding the use of dispersants. Discussion and work to develop this update have occurred over the past year, with the final approval taking place at the directors’ meeting in Seward, Alaska, on September 23, 2022.


Further materials on the evidence and rationale supporting the position update are currently being finalized by the Council for publication in early 2023.

PDF of news release: 

PWSRCAC Dispersant Use Position Press Release 

Plan for applying dispersants to crude oil spills in Alaska waters updated

Stricter rules applicable in certain areas

This map from the ARRT (larger image at the link) shows the “preauthorized area” between 24 and 200 nautical miles from shore (within the green boundaries). Within the preauthorized areas, some “avoidance areas” have been reclassified (striped areas) and will require the case-by-case approval.

The Alaska Regional Response Team, or ARRT, recently updated a list of areas that would receive extra scrutiny before dispersants are applied to a crude oil spill. The update completes the planned changes to the Dispersant Use Plan for Alaska. The plan is a guide for spill responders, and it spells out how oil spill dispersants would be used during a crude oil spill. The previous dispersant use plan had not been updated since 1989.

The first changes went into effect in 2016. Two different processes for deciding whether to use dispersants, depending on the location of the spill, were developed at that time. The application of dispersants is now considered “preauthorized” except for “avoidance” areas. In an avoidance area, a decision to use dispersants must undergo more extensive scrutiny on a case-by-case basis.

By pre-authorizing use of dispersants in certain areas, the ARRT can speed up the decision-making time on whether or not to use dispersants. Consultation with U.S. Fish and Wildlife and National Marine Fisheries Services is still required before dispersants would be used in a preauthorization area. For avoidance areas, additional consultation and a consensus between the Environmental Protection Agency, the Department of Interior, the Department of Commerce, and the Alaska Department of Environmental Conservation is required prior to use.

There is a short window of time after a spill when dispersants should be applied. Dispersants work best on freshly spilled oil.

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New plan for using dispersants in Alaska is in effect

The Alaska Regional Response Team, or ARRT, established a new plan earlier this year for how oil spill dispersants, an alternative oil spill response option, would be used during an oil spill. The ARRT is a group of federal and state agencies that share responsibilities for managing oil and chemical spill responses in Alaska.

Mechanical response, such as booms and skimmers that actually remove oil from the water, is the priority response option by state and federal law.

The new plan was effective January 27, 2016, although parts of the plan will not go into effect until 2018.

Details of new plan

The new plan describes two different processes for dispersant use. Dispersants will be “preauthorized” in certain areas, and all other areas are “undesignated.”

A new “preauthorization area” will go into effect in 2018. This area extends from 24 nautical miles offshore out to 200 nautical miles offshore (approximately 27.6 to 230 miles), south of Alaska’s mainland through the Aleutian chain. The ARRT’s rationale is that preauthorizing, or deciding before an oil spill occurs where chemical dispersants are allowed, could speed up response time. In the preauthorized area, dispersants are considered to be approved by government agencies before an oil spill happens. Therefore, the U.S. Coast Guard, as federal on scene coordinator, can decide to apply dispersants to a crude oil spill. Areas farther than 200 nautical miles from shore are international waters, and are not part of this plan.

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Environmental Protection Agency revising rules on oil spill dispersants

A vessel sprays water as practice for applying dispersants during an oil spill drill.
A vessel sprays water as practice for applying dispersants during an oil spill drill.

By Joe Banta
Council Project Manager

The Environmental Protection Agency is updating the rules for using chemicals, including dispersants, to respond to oil spills in the United States. This update is intended to address the concerns that arose during and after the BP Deepwater Horizon disaster in 2010. During that disaster, an estimated 210 million gallons of oil was spilled, and over 1.8 million gallons of dispersants were applied to the spill.

Dispersants are chemicals applied to spilled oil to try to break down the oil into small particles with the hope that these particles disperse into the water column rather than remain floating on the surface in a slick.

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