Oil recovery operations have been under way since May 27, and as of June 1 about 56,000 gallons of crude had been recovered, according to Tom DeRuyter, the state on-scene coordinator.

The spill flowed into a lined gravel containment area and did not reach the outside environment, DeRuyter said. The Trans-Alaska Pipeline System was shut down from for three days, restarting after federal officials signed off on a restart plan. There were no disruptions to tanker loadings at the Valdez Marine Terminal due to sufficient crude oil in storage at the terminal.

The spill occurred as Alyeska was conducting tests at the pump station during a scheduled maintenance shutdown of the pipeline.

"Alyeska had switched the station's power supply from the electrical grid to an uninterrupted power source battery. A control circuit failed to close a valve, allowing oil to flow from the TAPS line into tank 190 and then out the tank's vents into a lined secondary containment," the state agency said in a situation report.

The storage tank has a capacity of 55,000 barrels of oil.

Alyeska estimated the amount of spilled oil at between 208,950 gallons (4,975 barrels) and 212,520 gallons (5,060 barrels), based on observations of the pooled oil and assumptions about the volume and porosity of the gravel above the liner, the state DEC report said.

A more precise estimate will be made after the recovered oil is measured.

Oil recovery began May 27 and pumping of oil into tank trailers continued through the Memorial Day weekend. Recovered oil is being trucked to the Valdez Marine Terminal and unloaded into storage, the state report said.

The U.S. Pipeline and Hazardous Materials Safety Administration May 27 issued a corrective action order to Alyeska before giving the permission to restart. The order contained a number of steps PHMSA asked Alyeska to take before approving a pipeline restart.

"Among other activities, we are requiring Alyeska to prepare a restart plan that outlines how the company will operate the pipeline without the use of pump station 9 relief tankage and ensure the use of qualified personnel during restart and continued operational procedures," agency spokesman Damon Hill said in a statement.

Alyeska told PHMSA it can operate the pipeline without the relief tank at pump station 9 by relying on relief tanks at other pump stations.

Meanwhile, DeRuyter said the state Department of Environmental Conservation and federal agencies are focusing their investigation on why the battery back-up power system failed when the station was switched from its main power supply during a test.

Also, the investigation will focus on why it took operators at the pump station a period of time before they realized the tank had overflowed.

DeRuyter said operators at the time were focused on getting the power back on.

"The failure of the backup power caused screens in the pump station's operations control center to go blank. They couldn't see the tank," when it overflowed and crude oil began spilling, he said.

PHMSA, meanwhile, has filed against Alyeska eight federal enforcement actions totaling more than $1 million in fines. The majority of the enforcement actions have been pending for more than two years.

The cases allege violations of federal pipeline safety regulations, including paperwork errors and inadequate procedures, as well as safety violations discovered after pipeline accidents. Others cases allege violations of the rules for monitoring and fixing corrosion in the pipeline.

Out of seven pending cases with fines attached that the pipeline agency has filed against Alyeska since 2006, the company has paid only one civil penalty of $56,000 levied in 2008 for Alyeska failing to maintain records of repairs and not maintaining adequate corrosion protection on the pipeline near Glennallen.

Tim Bradner can be reached at

tim.bradner@alaskajournal.com.