Heating Oil Tank cleanup site — Restorical Research
Block 38 West
520 Westlake Ave N, Seattle, King County
Restorical Research
Preliminary Site-Specific Analysis

This property has a documented history as a property with a heating oil tank going back to 1890. Historical insurance policies issued during those prior operations and through 1986 could fund a cleanup — and recover costs already spent.

This Seattle property has a commercial history extending to the 1890s, beginning with lumber storage and progressing through blacksmith and wagon shops from 1905, warehouse operations, and a used car dealership in the 1960s and 1970s. A 1,500-gallon heating oil underground storage tank serving the 1919 building's oil-fired boiler was removed in 1989, and two additional bunker fuel oil USTs of approximately 1,200 and 2,200 gallons were discovered during excavation in 2020. Site investigations have identified polycyclic aromatic hydrocarbons, benzene, and diesel- and gasoline-range petroleum hydrocarbons in groundwater. Cleanup is underway under a Consent Decree through the Standard Cleanup program. That history could support an insurance cost recovery claim against carriers who issued insurance policies 40+ years ago.

Former Use
Former Heating Oil Tank
Address520 Westlake Ave N, Seattle, King County
Historical UseHeating Oil Tank
Est. Operating Since1890
StatusCleanup Started
Contamination & Investigation
Site Assessment Summary
ContaminantsPolycyclic aromatic hydrocarbons (PAHs), benzene, and petroleum hydrocarbons (diesel and gasoline range) detected in groundwater
Media ImpactedSoil, Groundwater
Regulatory ProgramMTCA — Standard Cleanup
Ecology Site #15008

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.

Petroleum storage at this property — heating oil for the 1919 building, bunker fuel oil for building mechanical systems, and operations spanning a used car dealership era beginning in 1962 — was well established decades before 1986. The PAHs, benzene, and petroleum hydrocarbons now detected in groundwater trace to those long-standing operations and their underground storage infrastructure. Occurrence-based CGL policies issued to the property's operators during that pre-1986 window may carry obligations both to recover remediation costs already incurred and to fund the cleanup work still ahead under the active Consent Decree.

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.