Pacific Wood Treating Corp

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. 

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 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.

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.