Landfill cleanup site — Restorical Research
King County Cedar Hills Landfill
16645 228th Ave SE, Maple Valley, King County
Restorical Research
Preliminary Site-Specific Analysis

This property has a documented history as a landfill going back to 1965. Historical insurance policies issued during operations at this property and through 1986 could fund a cleanup — and recover costs already spent.

Cedar Hills Regional Landfill has been in operation since 1965, receiving approximately 2,500 tons of refuse daily and more than 800,000 tons annually across multiple fill areas. Cleanup activities under the Standard Cleanup program have included a groundwater extraction system that operated for at least seventeen years and produced approximately 868,000 gallons in 2004–2005, an ongoing landfill gas extraction system with multiple wells, a permanent geomembrane cover installed by 1991, and a leachate collection system first constructed in 1979 and partially replaced in 1984. Remediation work is ongoing. That history could support an insurance cost recovery claim against carriers who issued insurance policies 40+ years ago.

Former Use
Former Landfill
Address16645 228th Ave SE, Maple Valley, King County
Historical UseLandfill
Est. Operating Since1965
StatusCleanup Started
Contamination & Investigation
Site Assessment Summary
ContaminantsLandfill leachate and landfill gas from unlined solid waste disposal areas affecting groundwater
Media ImpactedSoil, Groundwater, Surface Water, Air
Regulatory ProgramMTCA — Standard Cleanup
Ecology Site #7027

Why Historical Insurance Policies May Be Accessible

Pre-1986 Commercial General Liability (CGL) policies were occurrence-based and did not contain an effective pollution exclusion in Washington. If contamination occurred while those policies were active, those historical insurance carriers may still have a legal obligation to fund the cleanup costs, even if the business closed or the property changed hands.

Solid waste disposal at this site began in 1965 in unlined fill areas — more than two decades before 1986, when occurrence-based Commercial General Liability policies still carried no effective pollution exclusion in Washington. Ecology has specifically identified the pre-1986 unlined areas as a focus of investigation, tying the contamination directly to operations conducted during the window those policies were in force. The scale of documented remediation — long-term groundwater extraction, landfill gas control, geomembrane capping, and leachate management spanning decades — represents substantial expenditures that historical carriers may be obligated both to recover and to fund going forward.

Restorical's role is to locate viable historical policies, determine whether a successful coverage claim is possible, and assist our clients and their legal counsel to obtain insurance coverage. Restorical then manages the claim, including accounting, to ensure the cleanup is funded in a timely manner.

What We Look For

  • Historical insurance policies (pre-1986)
  • Policy numbers, carrier names, and coverage periods
  • Connection between contamination timing and policy period
  • Evidence linking cleanup obligation to insured activity

What We Deliver

  • Historical Coverage Chart
  • Trigger Analysis & Property/Policy Nexus
  • Coverage strategy with recommendations
  • Insurance funding for your remediation
  • Claims Management & Forensic Accounting

The Restorical Proven Process

Task 1 — Research and Analysis
Restorical searches for viable historical insurance policies, researches the site history, analyzes the contamination impacts, and underwrites potential coverage — including a proprietary trigger analysis. At the end of Task 1, we provide a clear yes or no on whether a successful cost recovery is possible, along with a strategy and recommendation specific to your situation, even if you are not the policyholder.
Task 2 — Coverage and Funding
When Task 1 confirms viable coverage, Restorical works with your legal counsel to tender the claim, negotiate and secure insurance coverage. Restorical will manage the ongoing claim process, including accounting to ensure the insurance companies are funding your remediation in a timely manner.

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This analysis is preliminary and based on publicly available records. Restorical Research is not a law firm and does not provide legal advice.