Weyerhaeuser Snoqualmie Mill

Ecology considers the status of this Site to be Cleanup Started. Cleanup Started indicates that some cleanup has been done, but additional work is needed to complete the cleanup. 

Cleanup related activities at the Site so far have been done as what the Model Toxics Control Act calls an independent cleanup. This means the owners or operators of the Site have done them without Ecology involvement.

​Ecology has not been directly involved in cleanup activities, but has been involved in permitting related to current property use. Ecology’s Water Quality Program issued industrial stormwater permit #WAR310172 on April 26, 2021, which covers part of the Site. The permit expires on December 31, 2024.

The Model Toxics Control Act (MTCA) is Washington’s environmental cleanup law. It provides requirements for contaminated site cleanup and sets standards that protect human health and the environment. Ecology enacts MTCA and oversees cleanups.

MTCA works on units known as cleanup sites (Sites). A Site is defined by the boundaries of where contamination from a specific source, in this case the former mill, has ended up. A Site may include part of a property, a whole property, or multiple properties.

​The MTCA site cleanup process is completed in steps over a variable timeline. It can take many years to complete the cleanup process at a Site.

Initial Investigation - Done

Weyerhaeuser first discovered contamination and reported it to Ecology in 1989. Ecology completed the Initial Investigation in 1990. Additional areas of contamination were discovered by Weyerhaeuser and reported to Ecology in 1991 and 2005. All of these areas of contamination are considered part of the Site.

Site Hazard Assessment - Done

In August 2021, Ecology completed a Site Hazard Assessment and the Site was added to the Hazardous Sites List. The Site Hazard Assessment included assigning a numerical rank of 1 to the Site using the Washington Ranking System (WARM). WARM ranks assign a numerical score to a Site’s potential threat to human health and the environment, relative to other ranked sites in Washington State. Ranks range between 1 and 5, where 1 represents the highest potential threat and 5 represents the lowest potential threat.

How was the Site contaminated?

The reported contamination mostly happened during normal mill work. Chemicals leaked or spilled in the areas where they were stored or used.

When did the contamination happen?

Snoqualmie Falls Lumber Company opened the mill in 1916. Ownership later transferred to the Weyerhaeuser Company, who continued mill operations until 1993. In general, contamination happened some time during the period when the mill was operating. In some areas, the timing can be narrowed down based on when a specific piece of machinery or process was used at the mill.

What chemicals are present and where are they located?

Contamination has been found in multiple areas within the Site. What chemicals are present depends on the area. The main areas of contamination identified so far are:

• Plywood Plant: A fire destroyed the plant in 1989. During the fire, electrical transformers were damaged and released fluid with polychlorinated biphenyls (PCBs) in it. 
• Petroleum Storage Tanks: Petroleum products, used for vehicles, machinery, and road oil, leaked out of the underground and aboveground storage tanks (USTs and ASTs) where they were stored. 
• Dip Tank: Pentachlorophenol was used as part of a wood treatment mixture for specialty products, and has been found near the location of one of the dip tanks where treatment happened.   
• Sawmill, Morbark Chipper, and Lumber Strapping Areas: Petroleum contamination in these areas is related to specific pieces of machinery that used products like lubricating oils.
•  Boiler Ash Fill Area: Ash from boilers used to produce steam was mostly disposed of off-property, but some ended up in shallow soils near the Powerhouse. Polycyclic aromatic hydrocarbons (PAHs) and arsenic are contaminants found in the ash. The Powerhouse building is still present at the east end of this area.
• Borst Lake: Borst Lake was used as a log pond for part of the time the mill was operating. Sediment in the lake has elevated concentrations of phenols, which are a byproduct formed when wood waste breaks down in sediment.  

All of these areas have documented contamination in soil and groundwater except for the Boiler Ash Fill Area (only contaminated soil) and Borst Lake (contaminated sediment).

What cleanup has been done so far?

Most of the cleanup work done at the Site so far was done by Weyerhaeuser. The work can be divided into two categories: characterization and remediation.

Characterization includes sampling to identify what media are impacted, what chemicals are present, and what the concentration of those chemicals is. Some characterization has been done in all of the areas listed above and in some additional areas on the Site. More characterization needs to be done as the Site continues in the cleanup process.

Remediation includes actions that remove the contamination from the environment. Excavation of contaminated soil has occurred in some of the contaminated areas – Plywood Plant, Petroleum Storage Tanks, Sawmill, Morbark Chipper, and Lumber Strapping. Additional remediation may be needed in these areas, and in other areas where no remediation has been done yet.

Weyerhaeuser owned all of the property associated with the Site until 2005, when Snoqualmie Mill Ventures purchased most of the Site. Weyerhaeuser Real Estate Development Company still owns Borst Lake. King County purchased the eastern edge of the former mill area from Snoqualmie Mill Ventures in 2015.

Snoqualmie Mill Ventures Property

The northeastern portion of this property is currently used for commercial activities, including RV and boat storage and storage of construction equipment and supplies. The southern portion of this property is used by DirtFish Rally School, for both driver training classes and general business operations.

There is a proposed redevelopment for this property. The development plan includes residential, commercial, and light industrial uses, and would be completed in three phases. The Snoqualmie Mill Ventures website has more information on the proposal.

King County Property

This property includes the former mill office building, currently used by DirtFish, and associated parking. King County purchased this area for the Parks Department to use as part of the planned route to complete the existing Snoqualmie Valley Trail.

Weyerhaeuser Property

The Borst Lake area is not currently being used for any commercial activities.

The City of Snoqualmie is the lead agency issuing the permits for redevelopment of the Snoqualmie Mill Ventures property. The permitting process includes the environmental review required by the State Environmental Policy Act (SEPA). As part of the SEPA review process for the Planned Commercial/Industrial Plan for the redevelopment, a draft Environmental Impact Statement (dEIS) was published in April 2020. The final EIS was published in December 2021. The EIS includes information on contamination and other topics related to the overall environment at the property, including things like wildlife, wetlands, and areas of historical or cultural significance.

Ecology’s role in the SEPA review process is to provide comments to the lead agency, who can consider them when they make their decision. Multiple Ecology programs reviewed the draft EIS document and provided comments to the City of Snoqualmie.

The most up-to-date information on the status of the redevelopment can be found on the City’s project website.

City of Snoqualmie:
Community Development
Phone: 425-888-5337
Email: communitydevelopment@snoqualmiewa.gov

Ecology Water Quality Department - Stormwater
​Amy Jankowiak
Phone: (206) 594-0165
Email: amy.jankowiak@ecy.wa.gov

King County Parks
Phone: 206-477-4527
Email:  parksinfo@kingcounty.gov

Snoqualmie MIll Ventures:
Tom Sroufe
Phone: 425-444-0812
Email: info@snoqualmiemill.com  

Mac McInnis
Phone: 425-442-6002
Email: info@snoqualmiemill.com

Weyerhaeuser Real Estate: online inquiry form