4407 Henderson Blvd SE, Olympia, WA 98501-4699


The Department of Ecology (Ecology) proposes removing the Briggs Nursery site from the Hazardous Sites List. Ecology invites your comments on the proposal during the public comment period

Please click on the photo for a larger view


The site is about 120 acres, and it is located north of the intersection of Henderson Blvd and Yelm Highway. The site is the former location of a wholesale nursery in operation since 1912. During the mid-2000s, the nursery moved away and the site is now changing to houses and businesses.


In 2002, Thurston County Health Department on behalf of Ecology decided a study of possible contamination was necessary based on information about pesticide use at the site. In 2004, Ecology put the site on the Hazardous Sites List because dieldrin (a pesticide) levels in some soil samples were above state cleanup levels.

In 2004, Briggs Nursery entered into an Agreed Order with Ecology to conduct a remedial investigation and feasibility study to find the extent of contamination and plan options for cleanup. As part of the investigation, owners tested soil, sediment, groundwater, and surface water for pesticides, metals, polychlorinated biphenyls (PCBs) and dioxins/furans.

Results of these studies showed there was no contamination of groundwater, or of nearby Ward Lake, from nursery operations.

Some areas at the site had dieldrin and PCBs contaminated soil exceeding state cleanup levels. To clean up the site, owners removed

  • 20,250 tons of dieldrin contaminated soil.
  • 1,811 tons of dieldrin and PCBs contaminated soil.

Following cleanup, concentration of contaminants in soil was below state cleanup levels, except for residual contamination remaining in the bottom of the kettles (natural depressions) at the site. Kettle landforms are created by melting ice blocks as a glacier retreats.

To eliminate possible exposure to contamination in the kettle bottoms, in 2008 an environmental covenant was filed for the site. The covenant restricts public access to the kettles and requires the owner to place fences and signs around the kettles. Thurston County is the current owner of the kettles and it is responsible for maintaining the fences and signs restricting public access to the kettle bottoms.

Ecology reviewed the cleanup work in combination with the environmental covenant that restricts access to the kettle bottoms and concluded that conditions at the the site are effective in protecting people's health and the environment. Ecology proposes removing the site from the Hazardous Sites List.



After the comment period ends, Ecology will post responses to the comments on the site webpage. Ecology may withdraw the proposal to remove the site from the Hazardous Sites List based on information given during the comment period. Otherwise, Ecology will remove the site from the list.

Because some contamination remains in the kettle bottoms, Ecology will periodically review conditions at the site to ensure that people's health and the environment continue to be protected.



Map showing site location as Thurston County, WA SITE INFORMATION


View Electronic Documents

Site Summary Report

Facility Site ID: # 35797926

Cleanup Site ID: 4150

Olympia, Thurston County

Status: Cleanup Started   Get definitions of Status terminology

Mohsen Kourehdar
Site Manager
(360) 407-6256

Nancy Davis
Public Involvement Coordinator
(360) 407-0067

Document Repositories:

Southwest Regional Office
300 Desmond Dr SE
Lacey, 98503-1274

Timberland Olympia Library
313 8th Avenue SE
Olympia, 98501-9300