News

Study estimates emissions from 2022 incident

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A new Council report contains an estimate of crude oil vapors emitted during an incident at the Valdez Marine Terminal in 2022.

Damage from snow and ice during winter 2021-2022

Over the winter of 2021 to 2022, excessive snow and ice built up on top of the vast tanks that store crude oil at the terminal, damaging the pressure vacuum vents on many of the tanks. In some cases, the vents were completely sheared off. These vents control the internal tank pressures, preventing dangerous overpressure or vacuum conditions.

The image shows two photos. One is a distance shot of the storage tanks, which demonstrates how vast the tanks are. The second photo is a closeup of the vents, which are metal and stick up off of the top edge of the tanks.
Oil is stored in tanks until it can be loaded onto ships for transport. Each of the storage tanks can store over 21 million gallons of crude oil.
Pressure vacuum vents are located on the outside edge of the roof on each tank. (Larger image)

During normal tank operations, the internal tank pressure can vary. Oil levels inside the tanks increase or decrease, and other factors such as sunlight heating the tanks can affect the internal pressure.

When the tank vapor pressures get too high, the vents can open and release those vapors to the atmosphere. They also prevent too much oxygen from entering the tanks, which could lead to a fire or explosion.

Damage to the vents led to concerns about the release of crude oil vapors into the surrounding atmosphere and other dangers.

Evaluating the impact

In incidents like these, precise emission volumes are difficult to measure. However, estimates can be calculated using key data points. Last year, the Council hired Dr. Ron Sahu, a nationally respected expert in air quality and engineering, to do just that. By gaining a better understanding of the volume of emissions that was released, the Council hoped to better understand the potential effects on the environment of Port Valdez or nearby residents from this incident.

The Council provided Dr. Sahu with documents from Alyeska and data from the State of Alaska, acquired via public records requests. From these documents, he was able to determine key points such as:

  • The number of tank vents that were damaged.
  • The extent of damage to individual vents.
  • The time period between when the damages were discovered until vent repairs were made and when pressure management of the tanks stopped.
  • The amount of oil in each tank.

Dr Sahu also considered ambient conditions such as temperature, among other factors to complete his analysis.

Using special software developed by the U.S. Environmental Protection Agency that calculates air pollutant emissions from organic liquid storage tanks, Dr. Sahu conservatively estimated that between 79 to 193 tons of volatile organic compounds and hazardous air pollutants were released into the surrounding atmosphere from February through March 2022. Dr. Sahu emphasizes that his estimate is conservative, and that the total is likely higher. Among other factors, he only accounted for losses when the oil levels were not changing in the tanks.

He also provided input on Alyeska’s response to the incident, including areas to improve safety.

Alyeska disagrees with the estimate

Dr. Sahu used the best information that was available to the Council at the time of the report’s release. In preliminary feedback provided by Alyeska, they disagreed with the report’s calculations, noting that they believe the total emissions to be lower. The Council has requested additional information on what Alyeska believes to be inaccurate; however, Alyeska has so far declined to provide any more feedback, limiting the Council’s ability to address their concerns.

Read the report

The full report details Dr. Sahu’s calculations and how he arrived at his conclusions: Report on VOC Emissions from Snow Removal Incident at VMT in 2022

Pilot test evaluates testing methods for buried liners

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How do you detect damage underground? The Council, Alyeska, and the Alaska Department of Environmental Conservation, or ADEC, have been trying to answer that question. The results from a recent pilot test are providing direction to help ensure that oil will not leak through the secondary containment liners under the storage tanks at the Valdez Marine Terminal.

Finding flaws in an underground liner

Last summer, Alyeska conducted a pilot test for locating damage in the special asphalt liners that surround the crude oil storage tanks at the terminal.

The liners are part of a system surrounding the tanks that is designed to prevent oil from leaking into the environment. The liners are difficult to examine because they are buried under several feet of earthen fill. Digging them up for inspection is expensive, time-consuming, and historically has caused damage.

Since the liners were installed nearly 50 years ago, only a small percentage has ever been uncovered and evaluated for damage. When sections have been uncovered, holes or cracks have been found about 19% of the time.

Both Alyeska and the Council have been looking for a method that can determine whether there are cracks or faults in the liner, and if so, where they are located, without having to dig, per requirements set by ADEC.

Results from pilot test

Of the methods that were tested last July, electrical leak location was determined to be the most feasible. This type of survey is done by applying electric currents to the ground outside the liner and measuring electric currents on the surface of the fill inside the liner. A solid liner would block the currents. Holes or cracks would allow the current to flow through. The currents that flow through the liner can be detected from the surface, allowing technicians to create a map of damaged areas.

Further analysis to come

Alyeska conducted this pilot test in preparation for a larger-scale test. When approving the last update to Alyeska’s oil spill contingency plan, ADEC placed a condition on the plan’s approval, requiring that Alyeska conduct further analysis of the liner. The timeline for these additional tests is yet to be determined.

How much of the liner needs to be tested?

The Council hired Dr. Craig Benson, Distinguished Professor Emeritus of the University of Wisconsin-Madison, and Dr. Joe Scalia, Associate Professor of Civil and Environmental Engineering at Colorado State University, to weigh in on the pilot test results. They determined that when the large-scale testing is done, at least 20% of the liner needs to be examined to be able to confidently estimate the frequency and size range of defects in the liner.

Details in the report:

Find out more about the pilot test and the expert’s recommendations in the report:

Anchorage office has relocated

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The Council is excited to announce that our Anchorage office has moved!

MAP to new location: RAM Building at 2525 Gambell Street, Suite 305.

New mailing address:

Prince William Sound Regional Citizens’ Advisory Council
2525 Gambell Street, Ste 305
Anchorage, AK 99503

All other contact information for the Anchorage and Valdez offices will remain the same.

Questions? Please call 907-277-7222.

Council held meeting and reception in Valdez, April 30 – May 2

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The Council held several events in Valdez, April 30 – May 2, 2025, including the Council’s annual Board meeting and a public reception.

Public reception: Wednesday, April 30

In conjunction with the meeting, the board of directors for Alaska Tanker Company, Hilcorp and the Council co-sponsored a public reception on Wednesday, April 30.

Board meeting: Thursday and Friday, May 1-2

The meeting was held in the Valdez Civic Center, at 314 Clifton Drive.

Meeting materials and links for teleconference, videoconference, and presentations.

Final agenda

On the agenda

The Council conducted regular business during the meeting, including seating of established directors and committee members, election of new Board officers and updates from Council ex officio members, staff and committees. Other topics included on the agenda were:

  • An activity report by Alyeska Pipeline Service Company on the Valdez Marine Terminal and Ship Escort Response Vessel System operations.
  • A review of a pilot study of methods to evaluate the integrity of the secondary containment liners in the East Tank Farm at the Valdez Marine Terminal.
  • A presentation on marine bird surveys conducted in September and November 2024, in and around the Prince William Sound tanker escort zone and Valdez Marine Terminal.
  • An update on non-indigenous species biofouling risks from vessels arriving in Prince William Sound.
  • An analysis of the preliminary conservative emission estimates from crude oil storage tanks at the terminal during the tank vent damage incident in 2022.
  • An update on recommendations from the Council’s report “Assessment of Risks and Safety Culture at Alyeska’s Valdez Marine Terminal.”
  • A summary of the Council’s monitoring of drills and exercises in 2024.
  • An update on community outreach activities done by the Council over the past year.
  • An overview of plans to further distribute the Council’s “Peer Listener Manual.”
  • A report from the Council’s legislative monitors and staff on political developments and prospects coming out of Washington, D.C. and Juneau.

Council board meetings are routinely recorded and may be disseminated to the public by the Council or by the news media.

Media release: Prince William Sound RCAC board meeting and reception in Valdez, April 30-May 2, 2025

 

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