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EPA, Northwest Natural Agree on Tar Clean-up in Portland Harbor
Release Date: 4/29/2004
Contact Information: Judy Smith
April 29, 2004
Sediment along the riverbank and river bottom next to the GASCO site is contaminated with tars containing polynuclear aromatic hydrocarbons and benzene. EPA has determined that removing the tar-body is time-critical and needs to take place quickly to reduce the possibility of releases of hazardous substances from the tar-body into the Willamette River and downstream areas. (See photo)
The Administrative Order on Consent (AOC) that the EPA and Northwest Natural voluntarily signed this week commits Northwest Natural to develop a work plan within 30 days, with the goal of completing removal of the tar-body in the river this summer, at times when the least impact to migrating salmon would occur. (The order is available by request or at https://yosemite.epa.gov/r10/cleanup.nsf/ph/GASCO .
GASCO, built and operated an oil gasification plant on the site between 1913 and 1956. From 1913 to 1941, waste and by-products from various gas production operations were discharged to a stream channel to the Willamette or low-lying areas of the site. From 1941 to 1956, wastewater effluent and tar still bottoms or residuals were disposed of in settling ponds. Approximately 30,000 cubic yards of tar waste had accumulated by the time the plant was shut down and the ponds were buried under 10 feet of fill in 1973.
“Northwest Natural is doing the right thing by agreeing to remove a known source of contamination in the river,” said EPA Regional Administrator John Iani. “In addition, the GASCO tar-body removal is responsive to public desires to get an early start on cleanup where it is possible.”