Trinity Lutheran Church

The site was issued a Site No Further Action Letter on December 5, 2007.

The Site is located at 4221 228th Avenue Southeast in Issaquah.  It is approximately 44 acres, and currently occupied by Trinity Lutheran College.  A detention pond is located on the property and used for containment of the stormwater and water expelled from the swimming pool and boiler.  A 500-gallon heating oil underground storage tank (UST) used to be located adjacent to the access road approximately 70 feet southeast of the pool and gym building. 

Contaminated soil was excavated from the detention pond and its three discharge outlets. The excavated area was restored with rip rap, and a discharge weir was created to contain any possible future release of oil.  Results from all the soil confirmation samples meet the state cleanup levels.

The UST was decommissioned and removed.  However, the product line was not removed outside the UST excavation area due to close proximity to the buried utilities. The product line did not show evidence of leaking heating oil.  Approximately 81 tons of petroleum-contaminated soil (PCS) were excavated and disposed of off-site. Oxygen release compound was applied to the sidewalls and floor of the excavation after PCS removal and before backfilling in order to make any residual PCS to break down at a faster rate and augment the bio-degradation of the residual PCS. Soil confirmation samples showed compliance with the state cleanup levels.

·         Total petroleum hydrocarbon and polycyclic aromatic hydrocarbons in soil in the detention pond

·         Total petroleum hydrocarbon as diesel in soil in the area where the former 500-gallon heating oil UST was located adjacent to the access road, approximately 70 feet southeast of the pool and gym building.