C St, Shelton, WA 98594



Ecology invites comment on the following draft documents for this Site. 

Ecology has provided the city with a grant of about $1.98 million to perform the RI/FS, dCAP, and implement the cleanup. 

Information about the Site and the comment period can be found in the fact sheet.

If you wish to view electronic documents related to this site, click on the "View Electronic Documents" link on the right under "Site Information".

For tips on submitting comments, visit our commenting tips webpage.

Check out website for updates on the status of our offices.


We will host an online informational meeting on the Shelton C Street Landfill on Thursday November 18, 2021.

  • 6:00 to 6:30 pm: pre-meeting technology check. Join early to fix any technical issues before the meeting.
  • 6:30 to 7:30 pm: Ecology staff will present information about the Site and answer questions. 

Join the webex event online by clicking on the link below or copy the link into your browser:

Event number: 2452 224 6510

Event password: Shelton1

Or join by phone at US Toll +1-415-655-0001 

Access code/Event number: 245 222 46510

Event password: 74358661

Contact Nancy Davis or call 360-489-4971 for dial-in support options and other online meeting support. 

Close to the meeting date, we will make the presentation slides available here.

General location of Shelton C Street Landfill - click to enlarge
Please click on the photo for a larger view


The Site is a 16.7-property. Before 1928, the property was mined for sand and gravel. In 1928, the city purchased the property and began using it as a landfill until the mid-1980s. The waste is located in an area of about four acres on the property.

The landfill received mostly residential solid waste. Other waste included research waste and demolition debris. As was a common practice for the era, landfill operators burned waste in the open and in an incinerator at the Site.

Sludge from the city’s wastewater treatment plant was brought to the landfill between 1973 and the mid-1980s. From 1976 to 1981, fly ash from the wood-burning power plant at the Simpson Timber Company mill was mixed with the sludge and put in the landfill. The sludge was disposed of in the northwestern part of the landfill.

Contamination sources at the Site are the solid waste and wastewater treatment plant sludge.


Contact with hazardous materials at the Site may harm people’s health and the environment.

Soil. People and animals at the Site could potentially contact contaminants in soil by directly touching contaminated soil or accidently eating it from dirty hands or paws. Contaminants in soil include:

  • Dioxins/furans.
  • Carcinogenic polycyclic aromatic hydrocarbons.
  • Metals (barium, copper, lead, mercury, selenium, silver, zinc, and lead).

Groundwater. Metals (arsenic, iron, and manganese) in groundwater at the Site are likely from naturally occurring sources in the soil. The groundwater is slightly acidic, likely caused by rainwater moving through the waste in the landfill. The acidic condition causes the metals in the soil to move into the groundwater. 

People will not be in contact with groundwater. The water table is located more than 35 feet below the bottom of the buried waste. Movement of groundwater is not likely a threat for spreading contamination away from the Site.

Landfill gases. Gases from breakdown of waste are not building up in the landfill. Landfill gases are not a threat to people and the environment at the Site.

Cleanup action layout. The soil cap will cover any location where waste is present..
Please click on the photo for a larger view


The plan describes several actions that would include a soil cap, institutional controls, and monitoring.

Low-permeable soil cap constructed to cover all of the landfill waste. The cap will prevent contaminants from coming into contact with people and animals.  

The bottom layer of the soil cap will be constructed with a geotextile barrier that is covered by at least a 2-foot-thick layer or clean, low permeability material. The top of the cap will be a 1-foot thick layer of topsoil covered with grasses and other shallow-rooted vegetation.

The cleanup is based on protecting drinking water down-slope from the Site. The cap will be sloped and will minimize rainwater from entering the waste. With the cap in place, we expect the acidic condition in the landfill to decrease and the metals in groundwater to decrease. 

Institutional controls will keep people from entering the Site and prevent future activities from damaging the cap. Institutional controls will include fencing, a gate, and signage. An environmental covenant will be recorded with the property deed and prevent any future activity that could expose people and the environment to contaminated soil or landfill waste. 

Monitoring will make sure the cap continues to be effective in preventing exposure to contamination. Groundwater will be monitored regularly to make sure the cap is effective and the amount of metals in groundwater decrease. 

We will review conditions at the landfill every five years. 


We will consider comments received during the comment period. If there are no changes, then we will approve the cleanup documents and sign the AO. The city will do the cleanup work. 


Once engineering design and construction begins, cleanup will likely take less than one year to complete. 


For more information about cleanup sites in the neighborhood and throughout Washington, go to:

  • What's In My Neighborhood is a map based search tool. Enter an address or zoom into an area to find sites.
  • Cleanup and Tank Search is a text-based search tool and lets you filter lists by location, contaminant, cleanup status, and more. 

These tools also show completed cleanups.


Map showing site location as Mason County, WA SITE INFORMATION


View Electronic Documents

Cleanup Site Details Report

Facility Site ID: # 1186

Cleanup Site ID: 2295

Shelton, Mason County

Status: Cleanup Started   Get definitions of Status terminology

Andrew Smith
Site Manager
(360) 407-6316

Nancy Davis
Public Involvement Coordinator
(360) 407-0067

Document Repositories:

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

Shelton Library
710 W. Alder St.
Shelton, 98584

Shelton Civic Center
525 W Cota Street
Shelton, 98584