Landfill cleanup site — Restorical Research
Cedar Hills LUSTs
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 1980. Historical insurance policies issued during operations at this property and through 1986 could fund a cleanup — and recover costs already spent.

This property is part of the King County Cedar Hills Landfill, where underground storage tanks supporting landfill operations were installed as early as the 1980s. One 1,000-gallon UST was removed in 1995 along with approximately 300 cubic yards of petroleum-contaminated soil, and three additional USTs were removed in 1996 with another 60 to 80 cubic yards of impacted soil excavated and backfilled with clean material. The UST remediation project spanned from 1995 to 2012 and concluded with a No Further Action determination, though the broader site remains under Ecology's cleanup oversight. The landfill continues in active operation. 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 Since1980
StatusCleanup Started
Contamination & Investigation
Site Assessment Summary
ContaminantsPetroleum hydrocarbons from leaking USTs detected in soil
Media ImpactedSoil, Groundwater
Regulatory ProgramMTCA — Standard Cleanup
Ecology Site #7173

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.

The USTs at this landfill were installed before 1986, placing their operational period within the era of occurrence-based Commercial General Liability policies that carried no effective pollution exclusion in Washington. Seventeen years of documented remediation — UST removals, large-scale soil excavation, dewatering, and long-term project oversight — generated substantial costs tied directly to those pre-1986 installations. Historical carriers who wrote CGL policies during that window may be obligated to reimburse those past cleanup expenditures, and because the site remains under active cleanup oversight, to participate in any future remediation costs that arise.

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.