Facility Site ID: 1019 Cleanup Site ID: 3020

Current Status

Figure 1. Residential neighborhood east of the Port of Ridgefield property affected by dioxin-contaminated soil. Click to enlarge.
Figure 1. Residential neighborhood east of the Port of Ridgefield property affected by dioxin-contaminated soil. Click to enlarge.

Soil sampling coming to the neighborhood east of the Port of Ridgefield's property.

Ecology and the Port of Ridgefield's consultant, Maul, Foster, Alongi (MFA) will be reaching out to homeowners in the neighborhood affected by dioxin-contaminated soil, located east of the port's property.

Property owners that already signed access agreements to sample their yards will be asked by MFA to confirm the access agreements. MFA will ask owners of recently purchased property for new access agreements to sample their yards. Agreement by the homeowner is voluntary.

The purpose of the soil sampling is to measure how many inches of soil is contaminated with dioxins. 

A fact sheet summarizes this information. 

Starting in 2009, Ecology and the port sampled soil to find the extent of dioxin contamination in the neighborhood. In 2018 and 2017, the port completed soil replacement in 29 residential properties and associated rights-of-way. 

Based on the yard soil sampling done since 2019, we know the extent of remaining dioxin contamination includes 15 residential yards and rights-of way (see Figure 1).

Next steps are to sample the depth of soil contamination in the 15 yards and rights-of-way to estimate the volume of replacement soil needed and design the Cleanup Action Plan. When the plan is ready, the plan and the legal agreement to implement the plan will be available for public comment. 

After these steps are completed, yard soil replacement will begin on the 11 parcels and rights-of-way shown in orange in phase 1 of the cleanup (see Figure 1). Soil replacement in the four parcels and rights-of way shown in blue will be completed later in phase 2 of the cleanup. 

At this point, timing is not clear for starting phase 1 and phase 2 of the cleanup. This partly depends on when the cleanup action plan is drafted, the comment period is completed, and the plan is finalized. 

Funds are available for cleanup of phase 1 properties and rights-of-way. Ecology needs to acquire funds to complete the soil replacement for phase 2 properties and rights of way. 

Site History

Click to enlarge
Click to enlarge

From 1964 to 1993, Pacific Wood Treating (PWT) operated in the general area of 111 West Division Street in Ridgefield. At the facility, PWT pressure-treated wood products and poles using a variety of hazardous chemicals, including pentachlorophenol. Commericial pentachlorophenol is a mixture that contains dioxins, which is formed when pentachlorophenol is manufactured. In 1993, PWT stopped using pentachlorophenol, when the facility closed and declared bankruptcy. In 1996 the port started cleanup of the facility. By 2015, cleanup at the former PWT plant site was completed.

Starting in 2009, Ecology and the port sampled soil in the neighborhood east of the port's property to find the extent of contamination from PWT that moved beyond the plant's boundary. Dioxins were the only contaminant found in soil above state cleanup levels in the area outside the port property. Dioxin-contaminated soil likely came from airborne dust from PWT operations. Dust may have blown off the port property, been tracked onto roads from truck tires, and come off trucks hauling treated wood on Ridgefield city streets.

Dioxins

Dioxins are made naturally by forest fires and volcanoes. They are also the unintentional by-product of burning from fireplaces, wood stoves, and exhaust from diesel engines. Dioxins are found everywhere because they do not break down easily in the environment. Most people are exposed to very low levels of dioxins when they consume food or milk, breathe air, or have contact with dioxin-contaminated soil.

Dioxins do not pose an immediate health risk. But long-term exposure to elevated levels increases the risk of health problems. Young children are more at risk than adults. The health risk comes from accidentally swallowing or breathing in the dust from contaminated soil over a long period. We recommend you protect yourself and your family by practicing healthy actions.

Healthy Actions

Dioxins transported by dust tend to stay in the upper layer of soil until they are disturbed. If you or your family are concerned, you can reduce exposure to potentially contaminated soil by doing healthy actions. 

  • Wash your hands after working or playing outside and before eating.
  • Remove shoes when you come inside the house.
  • Wear gardening gloves while gardening or landscaping. 
  • Wash food from the garden.
  • Vacuum regularly and dust with a damp cloth.
  • Wash children's toys often.
  • Use grass or other ground covers to help prevent exposure. Landscaping and development can also dilute dioxins in soil.

Past Cleanup

From June 2014 to early spring 2015, the port cleaned up:

  • Soil in the railroad overpass construction area.
  • Sediments in Carty Lake/Ridgefield National Wildlife Refuge.
  • Sediments in Lake River.

From 1996 to 2012, the port did partial cleanups to remove contamination. The port used a steam enhanced remediation system to remove wood treating chemicals from undergrounds. This system removed: 

  • 24,800 gallons of liquid contamination.
  • 1,545,000 pounds of contaminated sludge.
  • Contamination from over 1 million gallons of groundwater.

The port also removed 5,392 cubic yards of contaminated soil. They replaced the old stormwater system with new drains, piping, and outfalls. The port placed a clean soil cover over approximately 41 acres of land where PWT once operated, restoring the land for development.  

Site use restrictions called institutional controls are in effect

Institutional controls can be fences, signs, or restrictions on how the property is used. For instance, an institutional control may prohibit installing drinking water wells or disturbing a protective cap that isolates contamination. These restrictions keep the contamination contained and keep people from being exposed to the contamination. The controls are usually listed in environmental covenants recorded with the county.

Periodic reviews are required when institutional controls are required at a site. Ecology conducts reviews to make sure the controls remain effective and the cleanup still protects human health and the environment. We conduct periodic reviews about every five years.

Environmental Covenant

County Recording #: 6156256 COV
County Recording Date: 12/5/2023

Restrictions/Requirements

  • Control Vapor/Gas
  • Maintain/Protect Monitoring System
  • Ongoing Maintenance of Remedy
  • Prevent the Reuse or Relocation of Site Soil
  • Prohibit Soil Disturbance
  • Restrict Land Use

Restricted Media

  • Groundwater
  • Soil
Legal 8
Map 1
Document Title Document Date Document Type
Initial Off-property soil sample results map 10/30/2015 Map
Public Information 27
Document Title Document Date Document Type
Pacific Wood Treating Off-property Informational Fact Sheet 10/24/2023 Fact Sheet\Public Notices
Responsiveness Summary Pacific Wood Treating Site - De Minimis Consent Decree 8/1/2020 Responsiveness Summary
Union Pacific Comment Period Comment_ Brush 7/8/2020 Responsiveness Summary
Union Pacific Comment Period Contact List 7/8/2020 Responsiveness Summary
Union Pacific Railroad Company 5/19/2020 Fact Sheet\Public Notices
Neighborhood Soil Sampling Continues 5/1/2019 Fact Sheet\Public Notices
2017 Post construction Factsheet 8/31/2017 Fact Sheet\Public Notices
Right-of-way sampling results factsheet 12/9/2016 Fact Sheet\Public Notices
2016 Post Constuction factsheet 11/3/2016 Fact Sheet\Public Notices
PWT 2016 Pre-cleanup construction notice 7/20/2016 Fact Sheet\Public Notices
Factsheet on Interim Action Work Plan & SEPA public comment period 4/7/2016 Fact Sheet\Public Notices
Cleanup and Yard Replacement Process 10/30/2015 Fact Sheet\Public Notices
Healthy Actions poster 10/30/2015 Fact Sheet\Public Notices
Update on off-property soil study mailer 10/30/2015 Fact Sheet\Public Notices
Pacific Wood Treating Off-Property Soil Investigation FAQ 4/1/2015 FAQ (Frequently Asked Questions)
Pacific Wood Treating Neighborhood Soil Dioxin Study Presentation 3/10/2015 Multimedia
Pacific Wood Treating Neighborhood Soil Dioxin Study Sampling Process Handout 3/10/2015 Fact Sheet\Public Notices
Pacific Wood Treating Dioxin Investigation Community Meeting Postcard 2/24/2015 Fact Sheet\Public Notices
Pacific Wood Treating Off-Property Dioxin Investigation Fact Sheet 12/1/2014 Fact Sheet\Public Notices
Pacific Wood Treating Public Participation Plan 11/24/2014 Public Participation Plan
Pacific Wood Treating Update on 2014 - 2015 Cleanup Work 5/22/2014 Fact Sheet\Public Notices
Pacific Wood Treating RI/FS, Draft CAP, and Consent Decree Responsiveness Summary 11/14/2013 Responsiveness Summary
Pacific Wood Treating Fact Sheet for Consent Decree, RI/FS, and CAP 7/25/2013 Focus Sheet
Pacific Wood Treating Off-property fact sheet 1/25/2012 Fact Sheet\Public Notices
Pacific Wood Treating 2011 Interim Action Responsiveness Summary 6/14/2011 Responsiveness Summary
Pacific Wood Treating Interim Action Fact Sheet 4/15/2011 Fact Sheet\Public Notices
Pacific Wood Treating Fact Sheet Interim Action July 2010 6/7/2010 Fact Sheet\Public Notices
State Environmental Policy Act 6
Technical Reports 47
Document Title Document Date Document Type
Pacific Wood Treating - January 2024 Groundwater Monitoring for the Former Pacific Wood Treating Co. Site 4/3/2024 Groundwater Monitoring Report
Pacific Wood Treating - Comprehensive Operations and Maintenance Plan - Appendix E 1/22/2024 Operation and Maintenance Plan
Pacific Wood Treating - Comprehensive Operations and Maintenance Plan - Appendix C and D 1/22/2024 Operation and Maintenance Plan
Pacific Wood Treating - Comprehensive Operations and Maintenance Plan - Appendix A and B 1/22/2024 Operation and Maintenance Plan
Pacific Wood Treating - Comprehensive Operations and Maintenance Plan - Text, Tables, and Figures 1/22/2024 Operation and Maintenance Plan
Pacific Wood Treating Corp - Unrecorded EC Transmittal 11/29/2023 Site Specific Administrative Document - other (Administrative correspondence)
Pacific Wood Treating - Project Manager Change Notice 10/25/2022 Site Specific Administrative Document - other (Administrative correspondence)
Pacific Wood Treating Corp - Ecology Response to October 15, 2021 letter 7/19/2022 Site Specific Administrative Document - other (Administrative correspondence)
Construction Completion Report Overpass Property, Pacific Wood Treating 10/22/2021 Remedial Action/As-Built Report
PWT Groundwater Monitoring Report Aug 2021 10/15/2021 Groundwater Monitoring Report
Lake River 2020 Sediment Monitoring Report (Year 5) 2/1/2021 Performance/Confirmational Monitoring Plan or Report
Lake River Vegetation Monitoring 2020 Memo 12/16/2020 Performance/Confirmational Monitoring Plan or Report
Carty Lake Vegetation Monitoring 2020 Memo 12/16/2020 Performance/Confirmational Monitoring Plan or Report
Carty Lake 2019 Sediment Monitoring Report 1/28/2020 Performance/Confirmational Monitoring Plan or Report
Lake River Construction Completion Report - Appendix C - Photos 10/1/2018 Remedial Action/As-Built Report
Lake River Construction Completion Report 10/1/2018 Remedial Action/As-Built Report
Pacific Wood Treating GW Monit Rpt Jan 2018 5/10/2018 Groundwater Monitoring Report
Lake River Sediment Monitoring Report (Year 2-2017) 1/25/2018 Performance/Confirmational Monitoring Plan or Report
Lake River Vegetation Monitoring 2017 Technical Memo 11/21/2017 Performance/Confirmational Monitoring Plan or Report
Carty Lake Vegetation Monitoring 2017 Technical Memo 11/21/2017 Performance/Confirmational Monitoring Plan or Report
August 2016 groundwater monitoring for former Pacific Wood Treating Co. Site 10/18/2016 Groundwater Monitoring Report
Off-Property Portion Phase 2 Remedial Investigation Approach Memo 5/24/2016 Remedial Investigation Work Plan
Tech Memo-Cultural Resources Survey for the Port of Ridgefield Cleanup Project, Clark County, WA 4/7/2016 Initial Investigation Report
Off-Property Interim Action Work Plan Appendix B 4/4/2016 Interim Action Documents
Off-Property Interim Action Work Plan 4/4/2016 Interim Action Documents
Off-Property Portion Interim Action Work Plan 4/4/2016 Interim Action Documents
Carty Lake Sediment Monitoring Sampling and Analysis Plan 3/2/2016 Performance/Confirmational Monitoring Plan or Report
Carty Lake Construction Completion Report 11/17/2015 Remedial Action/As-Built Report
Lake River Sediment Monitoring Report Year 0 - 2015 7/1/2015 Performance/Confirmational Monitoring Plan or Report
Lake River Sediment Monitoring Sampling and Analysis Plan 4/9/2015 Performance/Confirmational Monitoring Plan or Report
Final Off-Property Portion Remedial Investigation Work Plan 4/2/2015 Remedial Investigation Work Plan
Carty Lake Engineering Design Report Appx DEF 10/22/2014 Engineering Design Report
Carty Lake Engineering Design Report Appx ABC 10/22/2014 Engineering Design Report
Carty Lake Engineering Design Report 10/22/2014 Engineering Design Report
Lake River 90% Remedial Design Report 3/3/2014 Engineering Design Report
PWT Railroad Ave Completion Report 1/13/2014 Final Cleanup Action Report
Carty Lake Predesign Sampling Report 1/8/2014 Engineering Design Report
Cleanup Action Plan for Pacific Wood Treating 10/14/2013 Cleanup Action Plan
Remedial Investigation and Feasibility Study for Pacific Wood Treating 7/25/2013 Remedial Investigation / Feasibility Study
Lake River Remedy Predesign Sampling Report 6/14/2013 Engineering Design Report
Carty Lake Predesign Sampling and Analysis Plan 5/28/2013 Engineering Design Report
Lake River Predesign Sampling Plan 9/28/2012 Engineering Design Report
Lake River Dioxin Natural Background Sediment Evaluation 11/18/2011 Site Specific Technical Document - other
Pacific Wood Treating 2011 Interim Action Work Plan - Cells 1-2 4/13/2011 Interim Action Documents
Lake River Sediment Remedial Investigation - February 2011 2/11/2011 Remedial Investigation Report
Pacific Wood Treating 2010 Interim Action Work Plan Cells 3-4 6/2/2010 Interim Action Documents
Pacific Wood Treating Corp Site Hazard Assessment 8/1/1996 Site Hazard Assessment Report
There may be more documents related to this site. To obtain documents not available electronically, you will need to make a public records request.

Places to see print documents

  • Southwest Regional Office
    300 Desmond Dr SE
    Lacey, 98503-1274
    Please schedule an appointment to view print documents at this location.

Contaminants 7

Contaminant Type
Soil
Groundwater
Surface Water
Air
Sediment
Bedrock
Halogenated Organics - Halogenated Organics S C
Metals - Metals Priority Pollutants C
Non-Halogenated Organics - Petroleum Products-Unspecified C C
Non-Halogenated Organics - Phenolic Compounds C C S C
Non-Halogenated Organics - Non-Halogenated Solvents S C
Halogenated Organics - Dioxins/Furans C S C
Non-Halogenated Organics - Polycyclic Aromatic Hydrocarbons C C B
S
Suspected
C
Confirmed Above Cleanup Levels
B
Below Cleanup Levels
RA
Remediated-Above
RB
Remediated-Below
R
Remediated
This contaminant list was based on our best information at the time it was entered. It may not reflect current conditions at the site.