Maralco

Ecology held a public comment period from October 10 - November 8, 2024 for the Interim Action Work Plan – Phase 2 Removal Action.  The document describes how cleanup of contamination from former waste piles will be conducted at the Site.

Ecology did not receive any public comments during the comment period.  The liable party will continue to clean up the Site under the Agreed Order.

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 implements the law and oversees cleanups.

​The MTCA site cleanup process is completed in steps over a variable timeline.

Estimated Timeline

2024: Phase 2 Interim Action

2024-2025:  Implementation of Remedial Investigation.

2025:   Perform the Feasibility Study

2026: Prepare the Draft Cleanup Action Plan

Each of the remaining cleanup process steps will require a public comment period. The graphic above shows these different stages of cleanup. Sometimes multiple stages occur in one public comment period.

The Owner plans to redevelop the property as a warehouse following the Phase 2 interim cleanup action including:

• Demolition of all existing structures (some demolition will occur in conjunction with the cleanup).
• Construction of an approximate 178,700 square foot warehouse building with concrete and asphalt loading dock, roads, and parking area. 
• Installation of new stormwater facility and new utility connections.

For more information about the redevelopment, please contact Kyle Siekawitch at
ksiekawitch@bridgeindustrial.com or call 425-749-4325.

Portions of the western wetland and portions of the on-property ditch will be filled, and a new wetland will be created along the eastern portion of the property.

For more information on wetlands can also be found on the Ecology Wetlands Webpage.

The City of Kent is the lead agency for the State Environmental Policy Act SEPA for the redevelopment activity.  The SEPA includes remedial investigation and interim action activities as part of the Ecology-supervised cleanup. In September 2024, a Modified Mitigated Determination of Non-Significant (MMDNS) was issued.  For more information, please contact Nate Schildmeyer, AICP at 253-856-5454, email nschildmeyer@KentWA.gov or mail to 220 4^th Ave South, Kent WA, 98032.

Cleanup work at the Maralco site started in 2023 under Ecology’s Voluntary Cleanup Program (VCP).  The VCP provides technical help to owners of contaminated sites to fulfill the Model Toxics Control Act (MTCA) cleanup standards while undergoing cleanup independent of Ecology oversight. 

As a part of the independent cleanup, the dross and other stockpiled wastes on the property and inside the building were removed.  This removal was Phase 1 of the interim action and was conducted from August 2023 to November 2023.  Approximately 35,300 tons of waste were removed from the Site during the Phase 1 interim action. 

After the waste piles and dross were removed, surface soil samples were collected from the area beneath the removed stockpiles. Sample results showed that residual dross and/or contaminated soil was present in the drainage ditches.  The contaminated soil beneath the former dross pile and within the ditches that was not cleaned up under Phase 1 of the interim action will be cleaned up during Phase 2.

The Maralco Site is located at 7730 South 202nd Street in Kent, WA. The Owner purchased the approximately 12-acre property in the Kent industrial area in June 2023. Until recently, the property also included a 45,000 square foot building near the western boundary that had been largely abandoned since 1986. The eastern portion of the property is covered by wetlands.

Maralco Aluminum Company, Inc. operated a secondary aluminum smelter from 1980 to 1986. The smelter produced aluminum ingots from recycled aluminum cans, Kawecki-Berylco, Inc. (KBI) dross, and scrap metal using the molten salt process. The wastes created from this process included black dross which is typically a mixture of aluminum and metals (primarily arsenic, barium, copper, and mercury) or “salt cake” (fluorides and chlorides).  Washed oxides (aluminum oxide) were produced when water soluble components of the dross (typically salts) were removed from the dross as part of re-processing. 

Several waste piles remained on the property from the smelting operation (see photos to right) until the Phase 1 interim action was performed in 2023. Other by-products such as the aluminum oxide were also stockpiled on the property and inside the smelter building. 

Maralco property aerial photo (2023)



Maralco property and wetlands (2023)



Abandoned smelter building (2023)



Maralco property aerial photo (1993)

Investigations through 2023 found the following contaminants of concern on the property: 

• Soil:  Metals, total petroleum hydrocarbons (TPH) from diesel fuel
• Groundwater: Metals, TPH, chloride, fluoride, and ammonia

Metals were also found in soil in the offsite drainage ditch located north of the property.

This plan includes information for the public regarding opportunities to get involved in the cleanup process. The outreach activities and mechanisms presented reflect Ecology’s current plans for keeping the public informed and for receiving information and comments from the public.

Ecology recognizes the importance of protecting and managing Washington's natural and cultural resources in collaboration with Tribes.

We engage with Tribes both in formal government-to-government relationships and through broader outreach whenever cleanup activities or contamination discoveries may affect tribal interests and resources. This engagement provides opportunities for tribal input throughout the cleanup process.

Ecology also works closely with the Department of Archaeology and Historic Preservation to ensure that any ground-disturbing activities comply with state and federal historical and archaeological preservation laws.

We are committed to providing environmental justice to our most vulnerable communities. It is a priority in our efforts to restore and protect land, air, and water. 

What's In My Neighborhood shows contamination cleanup sites in Washington state. Ecology encourages cleanup of these sites to protect the health of people, plants, and animals. Cleanups are projects that remove, treat, or contain potentially harmful substances.

To report an environmental problem or concern, any time, day or night, use the online reporting form.

Counties: Island, King, Kitsap, San Juan, Skagit, Snohomish, and Whatcom
Email: nwroerts@ecy.wa.gov
Phone: 206-594-0000

Ecology is committed to providing people with disabilities access to information and services. To request an ADA accommodation, contact Ecology by phone at 360-407-6831 or email at ecyadacoordinator@ecy.wa.gov. For Washington Relay Service or TTY call 711 or 877-833-6341.  Visit Ecology’s website for more information.

​If you speak a non-English language, free language services are available.

 주 환경부는 마랄코 현장 환경 정화와 관련된 공개 논평 기간을 공지합니다. 한국어로 된 문서나, 이 현장에 대한 한국어 정보를 원하시면 담당자 (Jintae Lee: 360-890-5596, jintae.lee@ecy.way.gov) 에게 연락하십시오.

To request language services (interpreting/translation), contact Ecology by phone at 425-393-5679 or email nancy.lui@ecy.wa.gov or visit https://ecology.wa.gov/About-us/Accessibility-equity/Language-services. For Relay Service or TTY call 711 or 877-833-6341.