Cascade Autovon Co


The Washington State Department of Ecology (Ecology) plans to remove the Cascade Autovon Company site from the Hazardous Sites List. The site is located at 12727 412th Ave SE in North Bend, Washington. The owners cleaned up contamination at the site under the Voluntary Cleanup Program. Ecology reviewed the cleanup and determined that:

  • The site is no longer a threat to human health or the environment; 
  • The site cleanup actions meet state cleanup standards;
  • No further action is needed.
We invite you to comment on several site documents from July 9 – August 7, 2018:
Ecology will be accepting comments on these documents until August 7, 2018.  You can comment by contacting one of the listed people to the right of this page, or with Ecologys E-Comment system.

If the comments received warrant no significant changes, Ecology will move forward with its No Further Action Letter and de-listing the site from the Hazardous Sites Lists. 


Ecology received a petroleum product release notification in June 1991 during an underground storage tank (UST) removal activity at the site. Ecology completed a Site Hazard Assessment (SHA) in June 2013. The resulting SHA rank for the site was 3, based on a scale of 1 to 5, where 1 represents the greatest potential impact to human health and the environment.
The main contamination identified in the SHA was diesel range petroleum hydrocarbon, in soil in and around the former UST excavation. Cleanup work included removal of 350 cubic yards of petroleum contaminated soil in 1991.  Some diesel contamination remained in soil after the excavation due to the presence of a security fence. The site was added to the Confirmed and Suspected Contaminated Sites List in July 2011, and to the Hazardous Sites List in August 2013. The site entered Ecology’s Voluntary Cleanup Program in October 2016.

Between 1992 and 2017, additional investigations were conducted to evaluate the remaining diesel contamination in soil. The additional work included the following:

  • In 1992 three monitoring wells were installed around the former UST. Ground water samples collected from 1992 – 1995 were below the state cleanup standards.  The three monitoring wells were properly decommissioned in 2018.
  • In 2007 another UST located within the same excavation was removed. Soil samples collected from the excavation were below the state cleanup standards. 
  • In 2016 and 2017 six soil borings were sampled around the former UST. All soil and ground water samples collected from these borings were below the state cleanup standards.

The soil sampling results confirmed that the remaining diesel concentrations detected in 1991 were in compliance with the state cleanup standards. The ground water sampling results confirmed ground water is in compliance with the state cleanup standards at the site.
The site cleanup qualifies for Ground Water Model Remedy No. 1, because the contaminated soil was removed to the greatest degree practical, and because soil and groundwater at the site are in compliance with state cleanup standards.


This site is under the Voluntary Cleanup Program at Washington State Department of Ecology. The Voluntary Cleanup Program enables owners of contaminated sites to meet state cleanup standards independently and to receive technical guidance from Ecology during the process.

The Voluntary Cleanup Program enables owners to work on a contractual basis rather than under an Ecology legal order. Participants in the Voluntary Cleanup Program pay fees to Ecology to cover the department’s costs for guidance and review. Voluntary Cleanup Program sites must meet the same cleanup standards as properties formally managed by Ecology under the state’s cleanup law, the Model Toxics Control Act, created by a 1989 voter initiative.


Map showing site location as King County, WA SITE INFORMATION


View Electronic Documents

Site Summary Report

Facility Site ID: # 36296841

Cleanup Site ID: 8879

North Bend, King County

Status: No Further Action   Get definitions of Status terminology

Jing Song
Site Manager
(425) 649-7109

Brad Petrovich
Project Planner and Public Involvement Coordinator
(425) 649-4486

Document Repositories:

Northwest Regional Office
3190 160th Ave SE
Bellevue, 98008-5452