Park Laundry Site

We are entering into a legal settlement, called a consent decree, with the City of Ridgefield. The consent decree is in the process of completion and will be finalized when signed by the court. The settlement requires the city to acquire the Park Laundry parcel that is the source of contamination and clean up contamination at the site. 

We held a comment period from August 10 to September 11, 2023, for public review of documents including Consent Decree DE 21768, draft Cleanup Action Plan, State Environmental Policy Act (SEPA) Determination of Non-Significance, and Public Participation Plan. 

We received two comments during the comment period. We considered the comments and did not change the documents. 

The comments and our responses are available in our responsiveness summary. 

From about 1965 to 1977, the Park Laundry property was a laundry and dry cleaners. Since then, the building was removed. 

Dry cleaners used tetrachloroethylene (PCE) as a solvent to clean soiled fabrics. During dry cleaning operations, PCE was released to the environment. Microbes in the environment can change PCE into trichloroethylene (TCE) and other chemicals. PCE and TCE contaminated soil and groundwater at the site. PCE and TCE are volatile chlorinated solvents (VOCs) that are hazardous to people’s health and the environment.

The Park Laundry property and the parcels on the north side of the property are the source area of contamination. Concentrations of VOCs in soil, groundwater, and soil vapor are highest in the source area and need to be addressed under the state’s cleanup law, the Model Toxics Control Act (MTCA).

Soil: Contaminated soil is generally limited to the source area. People using earth-moving equipment and in contact with contaminated soil may be exposed to VOCs by touching it or accidently eating it from dirty hands. People could be exposed by inhaling vapors while working in the source area. During excavation, a health and safety plan will reduce potential exposure to workers at the site. 

Groundwater: The area of solvent contamination in groundwater is called a plume. The plume is confined to shallow groundwater, so exposure to contamination from the site is not a concern for drinking water. The groundwater plume extends to the north and west of the source area and covers about 22 acres. People working in the source area might inhale solvent vapors from contaminated groundwater. If contaminated groundwater seeps into soil excavations, then people doing the excavating could be exposed to VOCs. Potential exposure of workers to contaminated groundwater at the site will be reduced by following the health and safety plan.

Vapor intrusion: VOCs are found in soil vapor, but vapor intrusion is not a pathway of concern at the site. Vapor intrusion occurs when volatile chemicals move from soil and groundwater up through buildings and into indoor air.

In 2012 and 2013, air inside and soil gas at buildings that sit over contaminated groundwater were tested. Outdoor air away from the site was tested for comparison. The VOCs detected in the buildings were likely coming from products used or stored in the buildings and from background sources--not from vapor intrusion coming from the Park Laundry site. 

In the future, if contamination remains in the source area and a building is constructed over the contamination, then additional work will be needed to show that soil vapor is not moving into the building.

Ecology’s plan is designed to clean up VOCs-contaminated soil and groundwater. The cleanup plan combines soil excavation and groundwater treatment to reduce the amount of contamination at the site. The plan includes a monitoring plan to make sure the cleanup is successful. Institutional controls will make sure the cleanup is effective in the long term.

Soil excavation and removal: The city will excavate about 1,000 square yards of contaminated soil to several depths below the surface. The engineering-design phase of the cleanup will determine the excavation area and depth more precisely. The excavated contaminated soil will be removed from the site and disposed of appropriately. Water collected from the excavations will be treated and properly disposed of. Removal of contaminated soil and water will reduce the source of groundwater contamination. Excavations will be filled with clean soil and the site returned to the original grade. Gravel or asphalt pavement will be used to cover the soil surface.

Groundwater treatment by bioremediation: A material that bioremediates groundwater contamination will be injected into the groundwater. The material includes microbes that naturally live in the soil and can breakdown the VOCs into non-hazardous compounds. The material also includes compounds that help speed-up microbial breakdown of VOCs.

Monitoring: Groundwater will be tested periodically to determine if the treatment is successful. If VOCs concentrations are not likely to decrease within a reasonable amount of time (like 20 years), then the groundwater will be treated again until monitoring results show the treatment is successful.

Institutional controls: The city will file an environmental covenant with the county. Among the covenant’s restrictions, it may limit land use and describe requirements for future development. With a covenant in place, Ecology reviews conditions at the site every five years.