Landfill cleanup site — Restorical Research
King County Sunset Park Tub Lake Dump
13659 18th Ave S, Seatac, King County
Restorical Research
Preliminary Site-Specific Analysis

This property has a documented history as a landfill going back to 1941. Historical insurance policies issued during those prior operations and through 1986 could fund a cleanup — and recover costs already spent.

This property served as a dumping area for waste oil and bilge oil from ships between 1941 and 1945, and later hosted a Public Works facility whose underground storage tanks contributed additional contamination. A 1983 Abandoned Landfill Study documented waste oil, diesel, Bunker C, methane, and lead contamination spread across a 2–3 acre footprint at depths of 10–12 feet. Cleanup work has included excavation and removal of USTs at both the Public Works facility and Parks office, installation of a weir skimmer system, recovery of approximately 100 gallons of waste oil from a recovery well, and fencing of the site — with cleanup continuing. That history could support an insurance cost recovery claim against carriers who issued insurance policies 40+ years ago.

Former Use
Former Landfill
Address13659 18th Ave S, Seatac, King County
Historical UseLandfill
Est. Operating Since1941
StatusCleanup Started
Contamination & Investigation
Site Assessment Summary
ContaminantsWaste oil, bilge oil, diesel, Bunker C, petroleum hydrocarbons, methane, and lead detected in soil and groundwater
Media ImpactedSoil, Groundwater, Surface Water
Regulatory ProgramMTCA — Standard Cleanup
Ecology Site #2794

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 contamination at this site originated from wartime dumping operations that began in 1941 — more than four decades before the 1986 threshold at which occurrence-based CGL policies began incorporating effective pollution exclusions. The Public Works facility's USTs, installed well before 1986 based on typical tank lifespans, and the presence of lead contamination consistent with leaded-gasoline use, both point to pre-1986 operational windows during which carriers issued policies with no enforceable pollution bar. The documented remediation expenditures — UST removals, groundwater recovery, skimmer infrastructure, and ongoing cleanup — represent costs that historical carriers whose policies covered these operations may be obligated to fund.

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.