State regulators have settled on excavation of contaminated soil and a protective cap to clean up and contain the worst of thepetroleum pollution on the Port of Astoria’s central waterfront.
“This is a major milestone in a long-term effort to clean up historical contamination that poses a threat to people, fish and wildlife,” Laura Gleim, a spokeswoman for the state Department of Environmental Quality, said of the state’s final decision. “The selected cleanup plan is a culmination of 25 years of investigation and 10 years of remedy development, negotiation and public involvement.”
Since the early 1900s, bulk fuel storage and distribution facilities, manufacturers, auto service stations and other industrial firms lined the Port’s central waterfront.
The operations left behind underground pipes, tanks and pockets of pollution under the Port’s docks. The heaviest stretch of pollution runs beneath a commercial complex at the corner of Gateway and Hamburg avenues and the Port’s former offices to the southeastern base of a slip between piers 2 and 3.
In the late 1990s, an underground pipe leaked near the Port’s old offices and released a sheen of oil into the Columbia River between piers 2 and 3. The state began negotiations with the Port, Niemi Oil, Harris Industries and McCall Oil & Chemical Corp. to investigate the cause and plan a cleanup.
The chosen remedy involves excavating contaminated soil between piers 2 and 3, filling the area with a sloped layer of clay, silt, sand and absorbent material to stop pollution from reaching the river. How the barrier will be protected from waves and rough weather will be determined during design. A soil venting system would reduce vapor from reaching buildings above the pollution. Monitoring wells would track effectiveness of the barrier.
Over the years, contaminants have been pumped out, pipelines decommissioned, underground storage tanks removed and the Port’s stormwater system rerouted to avoid the main areas of pollution around the central waterfront. Booms were placed at the base of Pier 1 to catch fuel leaching into the river. The measures have led to a general decrease of petroleum in the groundwater.
The excavation and cap would be a final step in the decadeslong cleanup. The state identified the Port, as the landlord, and three oil companies — McCall, ExxonMobil and Niemi — as responsible parties.
“DEQ will continue working with these parties to design and implement the proposed remedy in the next few years,” Gleim said.
The cost of the cleanup depends on the design. Previous sediment cap proposals topped $3.5 million.
Lawyers for the Port will detail the chosen cleanup plan at a Port Commission meeting Tuesday.