North Market St

The North Market Street site is located about one mile north of the City of Spokane. The approximate property boundaries are south of Gerlach Road, between North Market and Freya Streets and north of Lincoln Road. The site is over the Spokane-Valley Rathdrum-Prairie Aquifer, the sole drinking water source for more than 500,000 people.

Previously, the site was used as a petroleum storage and distribution center that was part of an oil refinery complex. Several of the properties that comprise the North Market Street Site were developed as industrial or commercial facilities that were involved in or related to the refinement, recycling, and sale of petroleum products.

In the late 1930s, properties including the current Tosco Spokane Terminal tank farm and distribution center were developed as part of an oil refinery complex. Waste management practices common during that era released liquid refinery-related petroleum wastes into the environment.

Refinery operations ended in 1953. The facility continued operations as a petroleum tank farm after refinery decommissioning.

Today, the Tosco Spokane Terminal continues to operate as a petroleum fuels storage and distribution center with an estimated cumulative capacity of about 391,500 barrels, or 16,443,000 gallons, of primarily automotive fuels. Since 1976, at least two major product spills have occurred at the Tosco Terminal Facility. The facility and properties that comprise the Site are primarily zoned for commercial and industrial purposes.

The Tosco Refining Company and Phillips Petroleum Company were responsible for site cleanup. The two companies merged during the cleanup action. Since the Tosco/Phillips merger, Phillips and Conoco merged creating the ConocoPhillips Company. Phillips 66 split from ConocoPhillips in 2012, and Phillips 66 retained responsibility for the cleanup.

Contaminants of concern include petroleum products, arsenic, and manganese.

As early as 1978, local land owners and businesses located north of the present day Tosco tank terminal reported petroleum-contaminated soils on lands just north of the decommissioned oil refinery complex.

In 1984, state officials confirmed the presence of petroleum contamination to groundwater from samples collected at three private water supply wells in the area. Use of those wells was discontinued, and Ecology began supplying bottled water to users at that time. In 1991, the North Spokane Irrigation District No. 8 completed a 16-inch water line loop as far north as Magnesium Road to provide a potable water supply to users previously requiring alternate supplies.

In 1990, the U.S. Environmental Protection Agency listed the North Market Street Site on the federal Superfund National Priorities List of hazardous waste sites requiring cleanup. After the Site was listed, Ecology assumed the lead to direct cleanup under the Model Toxics Control Act (MTCA).

The cleanup actions included:

• Contaminated soils from 15 to 20 feet below ground surface were removed. The removal combined with thermal (heat) treatment removed the potential pathway for direct skin contact and ingestion.
• A large source of groundwater contamination was removed.
• A technology called air sparging treated groundwater contamination through April 2014.
• A bioventing system decreased soil vapor concentrations though May 2019.
• Restrictive covenants were recorded on the fuel terminal property and properties that lie over the groundwater plume. The covenants limit land uses. Restrictions include no withdrawal of water, maintenance of fences and locked gates. These restrictions limit or prohibit any activity that will interfere with the integrity of the cleanup actions and require future owners to comply with these restrictions.

Periodic reviews

Periodic reviews are required when institutional controls are required at a site. Ecology conducts reviews to make sure the controls remain effective and the cleanup still protects human health and the environment. We conduct periodic reviews about every five years.

Three period reviews have been completed for this site. In the 2019 periodic review, we concluded soil and groundwater contamination is decreasing, but groundwater contamination remains that doesn’t meet state standards so the restrictive covenants will remain. Groundwater monitoring will continue. Further periodic reviews are required as long as the restrictive covenants are in place at the site.

Learn more in the reports

• 2019
• 2013
• 2008