Frequently Asked Questions

T-117 Site Background and Facts

Why are T-117 and adjacent streets and yards being cleaned up?
T-117 is designated by the Environmental Protection Agency (EPA) as an “Early Action Area” for the larger Lower Duwamish Waterway Superfund site. Due to its history as an asphalt-shingle manufacturing facility – Malarkey Asphalt and Duwamish Manufacturing – the T-117 site and the river sediments next to the property are contaminated and require cleanup. Additionally, contaminants were tracked by equipment off the site and into the adjacent neighborhood, causing the need for cleanup in some nearby streets and residential yards.

The Washington State Department of Ecology (Ecology) studies hazardous sites in the state, and assigns these sites with a ranking to estimate the potential threat the site poses if not cleaned up. T-117 is ranked as a “1” which represents the highest level of concern relative to other sites being studied by Ecology.

Who is conducting the cleanup?
The Port of Seattle and the City of Seattle are jointly responsible for cleaning up the T-117 Early Action Area. The Port owns the T-117 site and is taking the lead for cleaning up the uplands (T-117 site) and adjacent sediments (river). The City is taking the lead for cleaning up the adjacent streets and some residential yards. EPA is the lead environmental regulatory agency and is responsible for the oversight of the entire project. Neighbors and community members may hear from or contact any of these agencies regarding the cleanup. See a list of project team contacts here.
How were the boundaries of the study area defined?
The purpose of this cleanup is to remove highly contaminated sediment and soil that could be a source of contamination to the river. Originally, this site was identified for early cleanup based on high PCB concentrations in the river and on the former Duwamish Manufacturing and Malarkey Asphalt site, (which is the T-117 upland property). The site now consists of three cleanup areas: off-shore river sediments; T-117 upland property; and adjacent streets and some residential yards.

The sediment and upland cleanup boundary was determined based on extensive sediment and soil sampling. Contaminated sediments were removed between the shore and this clean sediment boundary, and replaced with backfill material, by the Port in 2014.

EPA identified a “Study Area” for streets and yards between T-117 and 14th Avenue South, Dallas Avenue South and South Donovan Street. The study area was defined using data from soil samples containing PCBs as they are the primary concern for recontamination to the river. Residential yards and streets have not been sampled for PCBs on the west side of 14th Avenue because Ecology’s source tracing data from area catch basins demonstrated there was not an accumulation of PCBs to indicate this area as a potential recontamination source to the river.

Is Basin Oil part of the cleanup?
Basin Oil is a privately-owned site that will not be cleaned up as part of the T-117 cleanup. Ecology has sampled the site and the surrounding groundwater and found very little contamination. It has been determined that recontamination of T-117 from the Basin Oil site is not expected.

For additional information, a recontamination analysis was performed for both Basin Oil and the South Park Marina in the Engineering Evaluation and Cost Analysis document (EE/CA).

Is South Park Marina part of the cleanup?
South Park Marina is a privately-owned site that will not be cleaned up as part of the T-117 cleanup. Recontamination of the waterway from the South Park Marina site is not expected based on sampling performed by Ecology. Any additional cleanup of the South Park Marina, if necessary, will be overseen by Ecology.

For additional information, a recontamination analysis was performed for both Basin Oil and the South Park Marina in the Engineering Evaluation and Cost Analysis document (EE/CA).

Is T-117 located in the city of Seattle or in unincorporated King County?
T-117, (formerly the Duwamish Manufacturing and Malarkey asphalt site), is located in unincorporated King County. The streets and yards portions of the T-117 site are located in the City of Seattle.
What is the estimated cost of the cleanup? What is the funding source?
The estimated cost of the cleanup is about $34 million. The cleanup is being funded by the Port of Seattle, City of Seattle, Ecology’s Toxics Grant Fund and insurance proceeds from the former companies on this site.
Are Duwamish Manufacturing and/or Malarkey Asphalt contributing to the cost of the Terminal 117 cleanup?
Both Duwamish Manufacturing and Malarkey Asphalt were involved in the lawsuit, which took several years to reach an agreement with the Port and the City, to clean up T-117. In addition to their earlier cleanup work at the site and other fees and expenses, the final settlement resulted in Malarkey and Duwamish (through their insurer) paying $10.5 million toward the cleanup.
How were the sampling locations identified?
Sample locations are generally selected based on what is known about the area and its past practices, areas where previous facility operations occurred, and in areas adjacent to where previous investigations revealed elevated contaminant concentrations. Specific sample locations and data results are provided in this project’s Sampling Plans.
Why were some streets and yards selected for cleanup and not others? Can I request to have my yard retested?
Streets and yards identified for removal have PCB levels greater than Ecology’s residential cleanup levels and also represent a possible source of contamination to the Duwamish River via stormwater erosion and run-off.

Between 2004-2009, extensive sampling was done in all residential yards facing South Donavan and Cloverdale Streets and 16th, 17th and Dallas Avenues South. Residential yards between South Cloverdale Street and Dallas Avenue South and west of 16th Avenue South had a higher potential for tracking out contaminants associated with historical operations at T-117. In other areas, sampling has been more focused on the portion of the yards adjacent to the road, which might have a higher likelihood of contamination from truck tracking.

The original sampling showed that, of the 24 yards tested within the Study Area, six contained areas where cleanup was needed. The sampling results and selection criteria are documented in the Engineering Evaluation and Cost Analysis document (EE/CA). Confirmation sampling was conducted in seven yards and an alleyway in 2012.

Have you done any sampling of the soils beyond the study area (i.e. outside South Park)?
The removal cleanup project is limited to soil and groundwater sampling within the footprint of the affected area, (i.e. the areas that were contaminated by the former asphalt plant at the T-117 site). The sampling area extended to about four blocks to the west and north from the T-117 site.

However, in 2009-2010, Ecology conducted a separate “Urban Seattle Area Soil Dioxin and PAH Concentrations” study, which sampled for dioxins/furans and Polycyclic Aromatic Hydrocarbons (PAHs). The results showed the concentrations in the neighborhoods west of 14th Ave South were on average a little higher than the state cleanup standards and lower than EPA’s proposed cleanup standards. More information about this sampling effort and the results can be found here.

To date, there have been no decisions by Ecology or EPA regarding these data.