Skagit State Bank

The Skagit State Bank Site is located at 1501 Cornwall Avenue in Bellingham, Washington. The Site is owned and occupied by Skagit State Bank. The property lies approximately 600 feet south of Whatcom Creek, on a gently north- sloping plain at an elevation of approximately 70 feet relative to mean sea level. The property is utilized as a walk-in and drive-through banking facility.
 
The property was developed around 1930 as a gasoline station, which operated at the Site until the early 1950s. A used car lot was located at the Site in the early 1950s. The property was redeveloped and has primarily been used as a bank since 1955 (BEK Engineering and Environmental [BEK] 2000).
 
Free product was discovered in December 1999 in a storm drain that discharges to Whatcom Creek. Ecology spill team personnel determined that the product appeared to originate from the Skagit Bank property. Further investigation identified an 800-gallon underground storage tank (UST) located on the Site that was leaking heating oil. The UST was removed, and analytical results for soil samples collected from the floor and sidewalls of the UST confirmed that soils surrounding the tank contained total petroleum hydrocarbon (TPH) concentrations exceeding the site-specific MTCA Method B cleanup levels for residential soil of 2,000 milligrams per kilogram (mg/kg). As a result, excavation and off-site disposal of contaminated soil from the heating oil UST pit was initiated in January 2000. During soil removal activities, gasoline contaminated soil was found at a depth of approximately 6 feet to 9 feet below ground surface (bgs) in the vicinity of the former UST (BEK 2000).
 
A new Site investigation was then completed based on the presence of gasoline contaminated soils in the vicinity of the former UST. Soil samples were collected using a push-probe drill rig down to an approximate depth of 20 feet bgs at 15 locations across the site. Silty clay soils were encountered at approximately 20 feet bgs across the site. Groundwater was encountered at only one location, where the push-probe was advanced through the clay layer at 35 feet bgs. Thirty-three soil samples and one groundwater sample were analyzed for petroleum hydrocarbon products, due to indications that the Site had primarily been impacted by petroleum hydrocarbon products (i.e., heating oil) covering a small area near the former heating oil tank at a depth of 10 to 15 feet bgs. In addition, groundwater was not found to be impacted at the Site (BEK 2000).
 
An Independent Remedial Action (VCP #NW0448) was completed at the Site in February and March 2000 to address TPH contaminated soils and free product entering the storm sewer from the site. The selected remedial action included removal of a leaking UST, abandonment of storm sewer pipes, and removal of contaminated soils. An abandoned storm water pipe that had provided a direct conduit for heating oil to enter the storm sewer was removed. Stormwater sampling was conducted in April 2000 in catch basins to verify removal of the source contaminants. A total of eight storm water samples were collected from two catch basins between April 3 and April 25, 2000. TPH was not detected above the laboratory reporting limit in any of the samples collected. Soil with TPH concentrations greater than 2,000 mg/kg were removed from the site, with the exception of a small area located at the corner of the bank building. Soil removal in this area would undermine the building structure; therefore, soil was left undisturbed at this location. Approximately 415 tons of TPH contaminated soil were removed and transported off Site for disposal. This area was later paved with asphalt. The estimated volume of contaminated soil left in place under the north corner of the bank building was approximately 10 cubic yards (BEK 2000).
 
A Restrictive Covenant limiting activity in the impacted area with remaining TPH soil contamination was filed with Whatcom County on September 27, 2001. Ecology issued a ‘No Further Action’ determination by letter on October 1, 2001 for the Site based on documentation submitted to Ecology for the independent cleanup and filing of the Restrictive Covenant (Ecology 2001a, 2001b).