Exxon Valdez Oil Spill (EVOS) Lingering Oil

Lingering Oil found on July 8, 2021 at the northwest bay of Eleanor Island. Photograph taken and provided by David Janka.

Proposed impaired nearshore areas in Prince William Sound included in the 2026 Integrated Report.

For more information, contact:

Terri Lomax
907-269-7635

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The Exxon Valdez oil spill (EVOS) occurred on March 24, 1989 in Prince William Sound (PWS). An estimated 11 million gallons of oil were spilled in PWS with only approximately 10% of the released oil recovered from beaches and surface water.

During the last 30 years, much of the unrecovered oil has disappeared due to natural processes and cleanup efforts, but a portion of the oil still lingers in areas sheltered from wave action or in fine-gained sediments covered by cobble. This sequestered subsurface oil is termed lingering oil and is generally not bioavailable unless disturbed.

Using grant funds from the Exxon Valdez Oil Spill Trustee Council, DEC's Division of Water has been reviewing scientific literature, data, and developing a tiered, science-based process to assess whether lingering oil impairs a beach assessment unit's designated use(s) found in 18 AAC 70. A beach assessment unit is a section of coastline with consistent geomorphic features that is evaluated as one unit for water quality assessments.

Based on this robust approach, DEC recommends delisting 11 previously impaired assessment units, leaving five assessment units as impaired, and adding no new impaired assessment units (see map). EVOS scientific literature from the past decade indicates minimal change in the amount and distribution of lingering oil in PWS. The change in impaired areas reflects DEC's more robust decision approach and modified assessment units that more accurately reflect geomorphic conditions.

Read more about this process in the documents below and in the 2026 Integrated Report. The Integrated Report is available for public comment through April 6, 2026.