Forensic investigation into sediment refutes legal claim against client, saving millions

Washington State Department of Transportation Tacoma, WA

Project highlights

Client challenge:
The Washington State Department of Transportation (WSDOT) built a public roadway near a legacy industrial property. The construction included a subgrade drainage system, connected to the stormwater sewer system that discharged into the head of the Thea Foss Waterway. In subsequent years, elevated levels of polycyclic aromatic hydrocarbons (PAHs) – chemicals found in petroleum, coal tar, creosote, and soot – were detected in the waterway, resulting in a Superfund remediation that cost the responsible parties more than $100 million. Citing the new roadway drainage system as a primary transport pathway for coal tar and PAHs from the former industrial site into the head of the waterway, some of the responsible parties and the U.S. Environmental Protection Agency filed two separate lawsuits against WSDOT. The lawsuits sought to recover more than $20 million of the remediation and agency oversight costs.

Our approach:
Haley & Aldrich performed a forensic evaluation of the existing remedial investigation data, and then developed expert reports and testified in both trials refuting the plaintiffs’ claims. Based upon an analysis of sediment data collected over nearly 20 years, watershed drainage runoff data, and air quality data, our findings identified a clear-cut alternate explanation for the elevation in PAH levels in the waterway, which absolved the subgrade drainage system as the primary cause of the conditions warranting remediation in the head of the waterway.

Value delivered:

  • The courts accepted Haley & Aldrich’s findings and found our client’s responsibility to be minimal, reducing the damages to a fraction of the claims.

Defense against remediation cost recovery claim

The complete story provides best defense against allegations of responsibility for sediment remediation

In the mid-1980s, our client built an access road adjacent to an industrial site that had previously undergone a lengthy remediation. More than two decades later, they found themselves the defendant in two separate lawsuits, alleging that the subgrade drainage system for the roadway provided a transport pathway for coal tar and associated polycyclic aromatic hydrocarbons (PAHs) from the industrial site to contaminate the Thea Foss Waterway in Tacoma, Wash.

As one of several constructed industrial waterways discharging into Commencement Bay, the Thea Foss Waterway was investigated as an extension of the Commencement Bay Superfund site. The waterway cleanup conducted in the mid-2000s required the City of Tacoma and various other responsible parties to spend more than $100 million on a cleanup to address multiple contaminants, focusing on coal tar residuals and PAHs in the head of the waterway. Now, several of the responsible parties sued our client to pay for the majority of the cleanup costs in the head of the waterway in a state trial, and then the U.S. EPA sued to recover a portion of its oversight costs in a federal trial. Combined, our client was sued for more than $20 million.

Sediment can’t testify – or can it?

The plaintiffs’ basis for their cost recovery claims was plausible, but was it correct? That’s what our client asked Haley & Aldrich to determine.

The team from Haley & Aldrich studied the history of contaminant sources and discharges into the waterway, including watershed runoff through storm sewers and air emissions during the 1980s and 1990s. The consideration of all factors influencing sediment quality led to a conceptual site model of contamination of the head of the waterway. PAH source forensic analysis was applied in the context of the working conceptual model to test various hypotheses.

The allegation that coal tar migration through the subgrade drainage system into the head of the waterway caused the conditions warranting remediation was countered with evidence showing that PAHs in “urban runoff” increased during the late 1980s due to increased PAH-containing soot in air emissions over that same period of time.

Our analysis and presentation of the facts proved persuasive. The judge in each of the two trials rejected the majority of the plaintiffs’ claims, significantly reducing our client’s liability for the cleanup. As a follow-up to our work, an allocator applied that same analysis to the natural resource damages claim, which also significantly reduced WSDOT’s responsibility.

For more information on this project, contact Helder Costa.