Pasco Bulk Fuel Terminal Site

The site, formerly known as the Port of Pasco site, covers nearly 90 acres and has been used primarily as a petroleum storage and distribution facility since the early 1940s. At one time the site housed 50 above-ground petroleum storage tanks as well as other smaller tank farms. In addition to petroleum, agricultural chemicals such as fertilizers, soil fumigants, and solvents were stored at the site. By 1999, all of the storage tanks were removed from the property.

As early as the 1950s, oil was seen on water discharged into a collection pond. Investigations beginning in 1969 discovered free-product petroleum in groundwater and soil.

We conducted a Site Hazard Assessment and ranked the site a 1 due to the levels of contamination and the site’s location near the Columbia River. A rank of 1 is the highest level of concern and 5 the least concern. The site was then added to the state's Hazardous Sites List. The site may be removed from this list after state cleanup requirements are met.

Petroleum and chlorinated solvents were found in soil and groundwater.

Treatment systems to address petroleum and chlorinated solvents in soil and groundwater were in place until 2018. Due to decreasing effectiveness, the parties responsible for cleanup proposed revising the remedial approach to monitored natural attenuation, or allowing contamination to degrade through natural processes. Treatment equipment remains on-site and available, but is no longer be used as the primary remedial action. 

Free-phase petroleum products consisting of gasoline and diesel were recovered until 2003. Monitoring ended in May 2006 since testing met state criteria.

Groundwater monitoring continues to evaluate cleanup progress.

We complete a periodic review at least every 5 years after cleanup construction is complete at a site when institutional controls are part of the cleanup. The purpose of the review is to evaluate site conditions to en​sure people and the environment are protected.

In January 2009, Ecology completed the first Periodic Review. Treatment systems continued to remove contamination from groundwater and soils at the site. Cleanup levels were achieved for some indicators in several monitoring wells. Monitoring wells 63 and 11A improved but still showed elevated levels of total petroleum hydrocarbons and/or benzene.

Arsenic still exceeded the cleanup level in most of the monitoring wells, and the dissolved oxygen in groundwater remained low. Perchloroethylene (PCE) exceeded the cleanup level at the oil-water separator, and contamination in monitoring well 48 had not shown a decreasing trend since July 2004.
 
The first Periodic Review identified several recommendations to continue improving site conditions. Generally, they included continuing treatment, evaluating and improving treatment systems, recommendations addressing the PCE contamination, and continuing monitoring.

Following the 2009 periodic review, a report reviewing potential additional cleanup actions was prepared. After discussing this report in 2014, an in-situ chemical treatment using lance injection to reduce hot spot concentrations was pilot tested. A combination of chemicals designed to enhance biological oxidation of contaminants were injected near monitoring well 63. Results were mixed, and ultimately Ecology agreed that the technology was not appropriate for full-scale application.

In July 2020, we completed the second Periodic Review and recommended no further cleanup actions. Groundwater monitoring will continue to track cleanup progress. Deed restrictions will be required if the site is redeveloped.