Heating Oil Tank cleanup site — Restorical Research
Denny & Warren Petrol Plume
101 Denny Way, 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 1968. Historical insurance policies issued during those prior operations and through 1986 could fund a cleanup.

The property at 101 Denny Way, developed in 1926, was heated by an oil-burning furnace from at least 1968 through 1997; petroleum contamination beneath and adjacent to the property is attributed primarily to that on-site heating oil use and to adjoining gasoline service stations whose underground storage tanks date to 1925. Remedial work tied to adjacent sources has included the removal of eight USTs and approximately 17,180 tons of petroleum-contaminated soil in 2005, and the recovery of an oil-water mixture from a leaking tank in 2014. Vapor intrusion mitigation — SVE system components and a vapor barrier installed under a new building — has been completed, and a neighboring parcel remains under active cleanup. The primary remediation of the contaminated plume beneath this property has not yet commenced. That history could support an insurance cost recovery claim against carriers who issued insurance policies 40+ years ago.

Former Use
Former Heating Oil Tank
Address101 Denny Way, Seattle, King County
Historical UseHeating Oil Tank
Est. Operating Since1968
StatusAwaiting Cleanup
Contamination & Investigation
Site Assessment Summary
ContaminantsPetroleum hydrocarbons (GRPH and DRPH) from heating oil storage and adjacent gasoline USTs, detected in soil and groundwater
Media ImpactedSoil, Groundwater
Regulatory ProgramMTCA — Standard Cleanup
Ecology Site #14751

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 contamination at this site traces to heating oil and gasoline operations that began decades before 1986 — adjacent tank installations date to 1925 and the on-site furnace was in service by 1968, both within the era when occurrence-based CGL policies carried no effective pollution exclusion. The carriers who issued those policies to operators storing petroleum beneath this city block for generations may remain liable under Washington's occurrence-based coverage rules. The primary soil and groundwater remediation work still lies ahead, and that forthcoming cleanup is precisely the category of expenditure pre-1986 policies were written 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.