Sunfair Chevrolet Inc

The site is an auto dealership and service facility. In March 1998, five underground storage tanks (USTs) were removed from the site. Tanks 1 through 4 each had a capacity of 1,000 gallons, and Tank 5 had a capacity of 3,000 gallons. Tank 1 contained motor oil, Tank 2 contained automatic transmission fluid, Tank 3 contained waste motor oil, Tank 4 contained diesel and Tank 5 contained waste motor oil. The tanks appeared to be in good condition upon removal.

Petroleum-contaminated soil was removed from the Tank 3 excavation pit until no visual indication of contamination remained. During removal, contamination was found to extend below the groundwater table. Following removal, soil samples were collected from the bottom and edges of the excavation pit and a groundwater sample was collected from groundwater flowing into the excavation pit. The final samples were analyzed for total petroleum hydrocarbons (TPH), and all detected concentrations were below Model Toxics Control Act (MTCA) Method A cleanup levels, except at Sample Number 6.
 
Sample Number 6 was collected beneath the concrete slab apron at the entrance to the facility. TPH-O (oil) was detected above MTCA Method A cleanup levels. However, since the consultant considered the environmental threat to be minimal, the residual petroleum contaminated soil was left in place to prevent disturbance to site operations. The environmental threat was determined to be minimal by the consultant due to the lack of petroleum contamination in groundwater, and the isolation of the contaminated soil by the concrete slab above. The petroleum-contaminated soil excavated from Tank 3 was reportedly stored on adjacent property for remediation by land farming.  

In an attempt to reduce the level of methylene chloride contamination found in the Tank 5 excavation pit, the excavation was left open for several weeks to allow the methylene chloride to volatilize.  No sources were identified for the methylene chloride contamination.

An institutional control was imposed to prevent exposure to hazardous substances remaining at the site. The institutional control consists of a surface cap formed by building foundations and a concrete pad or asphalt pavement over the area of concern. To ensure protectiveness of the remedy, an environmental covenant was recorded to prohibit or limit activities that would interfere with the integrity of the surface cap.

Based upon cleanup activities and the recording of the environmental/restrictive covenant, Ecology has determined the site is no longer a threat to human health and the environment. Ecology issued a no further action determination in February 2015.

Periodic reviews are conducted every 5 years by Ecology for sites that have 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

Based upon the site visit conducted in March 2021, the site continues to operate as an auto dealership and repair facility.  

The cleanup actions completed at the site appear to be protective of human health and the environment.

Soil cleanup levels have not been met at the site; however, the cleanup action 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 environmental covenant for the property is in place and is expected to be effective in protecting public health and the environment from exposure to hazardous substances and protecting the integrity of the cleanup action.

If the existing structures be removed or replaced, contaminated soils beneath the site must be remediated.

Based on the periodic review, Ecology has determined the restrictions in the environmental covenant are being observed. No additional remedial actions are required by the property owner. It is the property owner’s responsibility to continue to inspect the site to assure that the integrity of the site surface is maintained.