Tiger Oil 24th Ave & W Nob Hill

This Tiger Oil Site is located at 2312 W Nob Hill Boulevard in Yakima, Washington.  In 1981, an explosion occurred in a drainage line adjacent to the Site which triggered an initial search for released fuel from the Site.  The explosion resulted from the presence of explosive levels of gasoline vapors which accumulated in and around the line.  Tank and line testing conducted by Tiger Oil Company in September 1982 showed a leaking pipe to a regular leaded gasoline dispenser at the station.

From 1982 to 1984, approximately 20,000 gallons of petroleum product leaked from the underground storage tank system at the retail petroleum station.  The petroleum has contaminated the soil and groundwater both at the Site and on adjacent properties. 

The site is currently on Ecology’s Hazardous Sites List with a ranking of “1”.  Sites on the Hazardous Sites List are a priority for Ecology, and have completed a Site Hazard Assessment (SHA). A SHA provides information about the environmental risk of the site. Risk is based on the amount of contaminants, how toxic they are, and how easily they can come in contact with people and the environment. Sites are ranked relative to each other on a scale of “1” to “5”; with a rank of “5” being the lowest.

Following the release, an interim action was conducted that consisted of the installation of a simple product recovery system.  Over 16,000 gallons of gasoline were recovered from soil and groundwater over the following 2 years. 
An interim remediation system, consisting of a groundwater and soil vapor extraction (SVE) system was operated from 1995 through 2006 to reduce the level of soil and groundwater contamination and to prevent contamination from moving onto adjacent properties.  

Ecology entered into a Consent Decree in 2004 to implement a cleanup action plan at the Site.  The leaking tanks have been removed, and 700 tons of contaminated soil were transported off-site. 

A restrictive covenant was recorded for the Site in 2005 which restricts the use of groundwater at the Site for domestic purposes.

The City of Yakima purchased the property in 2014.  Ecology and the City of Yakima entered into an Amended Consent Decree in September 2014 to implement an amended cleanup action plan at the Site.

During late spring and early summer of 2015, the former Tiger Mart building was demolished after all asbestos had been removed from the building.  Asphalt pavement within the extent of the excavation was also removed.

During excavation activities, shallow uncontaminated soils (from ground surface to approximately two feet below ground surface) were removed and segregated in stockpiles for screening. If screening indicated the absence of petroleum contamination, the stockpiled soils were stored on site for use as backfill. Excavation near the building footprints of adjacent buildings was limited in order to protect the integrity of the building foundations.

Petroleum contaminated soils were removed from approximately 9 to 14 feet below ground surface. A proprietary mix of chemicals were mixed with clean soil and used to fill up the excavated pit.  Approximately 8,740 tons of petroleum contaminated soils were transported to Anderson’s petroleum contaminated soils facility in Yakima, Washington.  Three additional groundwater monitoring wells were installed when backfilling was completed.

Groundwater monitoring will begin in November 2015, and continue every three months. This data will be used for making future cleanup decisions at the Site.

Periodic reviews are conducted every 5 years by Ecology for sites that have Environmental Covenants and/or Institutional Controls. The review is intended to examine the effectiveness of cleanup activities and to assure the continued protection of human health and the environment.

Periodic Review Results

• The remedy implemented at the Site to date does not meet the minimum requirements of MTCA and fails to be protective of human health and the environment; however, contaminants at the Site do not pose an immediate threat to human health and the environment. Exposure to contaminated soil, groundwater, and NAPL remaining beneath the Site is not likely as long as institutional controls and permanent Site surfaces are maintained.
• Soil and groundwater cleanup levels have not been met at the Site; however, the cleanup action for the Property is determined to comply with cleanup standards under WAC 173-340-740(6) (f), since the long-term integrity of the containment system is ensured and the requirements for containment technologies have been met.
• The restrictive covenant for the property is in place and will be effective in protecting public health and the environment from exposure to hazardous substances and protecting the integrity of the cleanup action.

Based on this periodic review, the Department of Ecology has determined that the requirements of the restrictive covenant are being followed. Additional remedial actions are required by the property owner, and are ongoing. It is the property owner’s responsibility to continue to inspect the Site to assure that the integrity of the cap is maintained.