Midstate Aviation

The site is located north of Ellensburg at 1101 Bowers Road and is also known as "Bowers Field".  Midstate Aviation has operated as an aerial pesticide application service from this site from 1961 to the present.  Allegedly, discharge of rinsate to the ground ceased during 1974. Regardless, incidental spills and releases of pesticides and herbicides during aircraft tank loading and rinsing operations with these chemicals resulted in soil and groundwater contamination. Contaminants of concern include DDT, DDE, and Dinoseb, amongst others.

After a Site Hazard Assessment, the Site was ranked a “3” on the Hazardous Sites List. The Hazardous Sites List is a statewide list of contaminated properties.  Sites can be ranked from a “1” to “5”.  A rank of “1” is the highest level of environmental concern compared to other sites on the List, and a rank of “5” is the lowest.

In September 1997, Kittitas County and Ecology entered into an Agreed Order for a Remedial Investigation/Feasibility Study at the site. The focus of this work was to identify the source and extent of contamination as well as cleanup options. In addition, an amendment to the original agreed order was made which allowed for implementation of interim actions. These interim actions consisted of off-site disposal of approximately 2,000 cubic yards of pesticide contaminated soils, testing at various depths and groundwater monitoring via 2 existing wells, and the construction of 2 new wells for a total of 4 monitoring wells.

As a result of the soil removal, sampling, and groundwater monitoring that has taken place at this site since 1997, Ecology determined that the site does not pose a threat to human health or the environment. The Site was removed from the Hazardous Sites List.