Superfund Information Systems: Site Profile

Superfund Site:

HARBOR ISLAND (LEAD)
SEATTLE, WA

Cleanup Activities

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Background

Harbor Island is an industrial island in Seattle, Washington's Elliott Bay. Built in the early 1900s, the 420-acre island supports businesses that conduct commercial and industrial activities, including ocean and rail transport operations. Site operations contaminated groundwater, sediment and soil with lead and other contaminants. Many Superfund sites like Harbor Island are large and complicated. These sites are often broken up into smaller areas to make cleanup easier and more manageable. These areas are called "Operable Units" or OUs. The EPA divided the site into six OUs, to better address site cleanup. The entire island and associated sediments are designated as the Superfund site. Cleanup decisions have been made at five OUs, and the remaining OU for cleanup is the East Waterway.

The East Waterway (EW) is a maintained waterway that was created during the construction of Harbor Island. Since the creation of Harbor Island, the original estuarine mudflat area has been either filled or dredged and channelized to create the EW. Early industrial and commercial use of the EW consisted of fish processing facilities, shipyards, and facilities with flour mills, grain elevators, lumber yards, and cold storage originally focused on the eastern shore. Wharves constructed on creosoted piles were built in the early 1900s along both sides of the EW. Commercial and industrial use continued after the 1940s on both sides of the EW, including oil terminals, shipyards, rail transfer terminals, cold storage, lumber yards, and sand and gravel transfer stations. From these uses, the mud of the EW is contaminated with high levels of pollutants including polychlorinated biphenyls (PCBs), arsenic, carcinogenic polycyclic aromatic hydrocarbon (cPAHs), tributyltin (TBT), and mercury. The potential sources of contaminants are both historical and from potentially ongoing sources.

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What Is the Current Site Status?

To date, the Harbor Island Superfund cleanup sites have been cleaned up and are undergoing long-term monitoring to ensure the cleanup activities are protective to human health and the environment. The site is being addressed through federal and potentially responsible party (PRP) actions.

The EPA has conducted several Five-Year Reviews of the site's remedy. The purpose of a Five-Year Review is to determine whether the remedy at a site continues to be protective of human health and the environment. For the remedy to be protective in the long term at Harbor Island, appropriate restrictive covenants must be recorded; cap inspections and maintenance must be completed annually; light non-aqueous phase liquid (LNAPL) removal must continue at Todd Shipyard; the groundwater monitoring program may need to be modified; and all the island's groundwater monitoring programs need to be coordinated. Contamination remains in both the uplands soil and sediments at concentrations greater than allowable for unrestricted use. Some institutional controls (ICs) are in place, such as restrictions in using groundwater for potable purposes, unrestricted excavation and "no anchor" areas. Most of these restricted areas are on properties owned by or under the control of large potentially responsible parties, i.e., Port of Seattle and major oil companies. In addition, Five-Year Review Reports identify issues or deficiencies found during the review, if any, and recommendations to address them.

For the East Waterway, because it has limited public access and a greater concentration of commercial shipping activity, swimming, kayaking and other recreational use of the waterway is limited or rare. However, recreational fishing by people other than tribal members is known to occur on the waterway despite existing fish advisories. The main way people are exposed to the chemicals in the East Waterway is by eating the seafood that live in the river year round.

A Washington Department of Health fish consumption advisory, warning individuals not to consume contaminated resident seafood caught in the waterway, is in place. However, salmon are safe to eat since they only pass through Elliott Bay and do not live year-round in the bay.

Special advice for fish consumption in the Puget Sound, Elliott Bay, the Lower Duwamish River, and other rivers is available from the Washington Department of Health and King County.

The Harbor Island site is heavily industrialized and is expected to remain industrialized in the future. There are currently no residences on the island. Many Superfund sites like Harbor Island are large and complicated. These sites are often broken up into smaller areas to make cleanup easier and more manageable. These cleanup areas are called “Operable Units” or OUs. The EPA divided the Harbor Island site into six cleanup areas, or operable units (OUs), to better address site cleanup. The entire island and associated sediments are designated as the Superfund site. Most of these cleanup areas are on properties owned by or under the control of large potentially responsible parties (or PRPs), i.e., Port of Seattle and major oil companies. The EPA has conducted several Five-Year Reviews of the site's remedy. The purpose of a Five-Year Review is to determine whether the remedy at a site continues to be protective of human health and the environment. Through these reviews, the EPA ensures that the remedies are working at the cleanup areas.

Five OUs of Harbor Island have been cleaned up:

  • Soil and Groundwater OU: Removed contaminated soil, treated and disposed soil off-site; capped remaining soil; implemented Institutional Controls (ICs); implemented long term removal and treatment of petroleum-related products, and continued with the shoreline groundwater monitoring program.
  • Tank Farms OU: BP, Kinder Morgan and Shell excavated and disposed of lead and arsenic contaminated shallow surface soil; removed total petroleum hydrocarbons (TPH), treated and disposed this soil off-site; treated remaining contaminated soil and groundwater; used natural processes to lessen contamination; implemented long-term groundwater monitoring and ICs.
  • Lockheed Upland OU: On Harbor Island, removed upland contaminated soil, treated and disposed soil off-site; capped remaining soil contamination; continued long-term groundwater monitoring; and implemented stormwater management.
  • Lockheed Shipyard Sediments OU: Demolished the existing pier on the West Side of Harbor Island and removed approximately 6,000 creosote-coated piles; dredged the nearshore area and capped remaining sediments; created a riparian buffer and a habitat-friendly soil layer on top of the capped sediments.
  • Todd Shipyards Sediments OU: Dredged the area near the berth; demolished piers; capped contaminated sediments under the remaining piers; and created a habitat area at a capped nearshore area.

The one area that remains to be cleaned up is the East Waterway. The EPA is overseeing the cleanup of the East Waterway, which is primarily conducted by the East Waterway Group. The Group consists of the Port of Seattle, the City of Seattle, and King County. The Port is leading the cleanup work under a legal agreement with the EPA. The City of Seattle and King County are supporting the Port's efforts and are conducting source control measures under EPA oversight.

In 2014, the Remedial Investigation (RI) was completed. Information gathered from the Remedial Investigation (RI) helps the EPA determine the best and most efficient ways to address the threats to human health and the environment from the East Waterway sediment. The data from the RI will support the analyses conducted in the Feasibility Study that is currently underway.

The Study will evaluate a range of options for cleaning up the contamination.The EPA is evaluating several cleanup options that will consist of removal of contaminants by dredging, capping over contaminants with an engineered clean sand cap, adding thin layers of sand to less contaminated areas where sediment does not move, and monitoring contaminant concentrations over time to ensure contaminant levels area decreasing.

The cleanup options will be detailed in a final document called a Feasibility Study (FS). The FS outlines the different methods available for sediment cleanup and describes a wide range of ways to combine those methods into cleanup alternatives. The EPA will use the both the RI and FS reports to help prepare a proposed plan to clean up the East Waterway. The Proposed Plan will summarize cleanup alternatives and propose a preferred course of action.

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