Harbor Island Lead

⚠ Superfund · Cleanup underway

To date, cleanup decisions were made by EPA at five of the Harbor Island operable units and by the Washington Department of Ecology at the Tank Farm OU. These OUs are undergoing long-term monitoring to ensure the cleanup activities continue to protect people’s health and the environment.

Location

CitySeattle
CountyKing County
StateWashington
Coordinates47.57940, -122.35220

Contaminants of concern

Contaminated media

Cleanup timeline

  1. Initial Assessment Completed — 01/01/1980
  2. Proposed to the National Priorities List — 12/30/1982
  3. Finalized on the National Priorities List — 09/08/1983
  4. Remedial Investigation Started — 09/07/1988
  5. Remedy Selected — 09/30/1993
  6. Final Remedy Selected — 05/28/2024
  7. Remedial Action Started — 07/31/1995
  8. Construction Completed — Not Yet Achieved
  9. Deleted from National Priorities List — Not Yet Achieved
  10. Most Recent Five-Year Review — 09/12/2025

EPA references

Other Superfund sites in King County

EPA-regulated facilities nearby

Understanding this Superfund site

Harbor Island Lead is a federal Superfund site in Washington. The Superfund program, created by Congress in 1980, addresses sites where hazardous substances have been released or threaten release into the environment. EPA scores potential sites using the Hazard Ranking System; those that score high enough are placed on the National Priorities List.

Current status: Cleanup underway. Active cleanup is underway, meaning EPA has approved a remediation plan and work is in progress. Cleanup timelines vary widely — some sites take decades depending on contamination depth, groundwater involvement, and funding availability.

EPA has identified 10 contaminants of concern at this site, including 1,1,1-trichloroethane, 1,2-dihydroacenaphthylene, 1,4-dichlorobenzene. Contamination has been detected in groundwater, sediment, fish tissue, soil.

If you live near this site and have health concerns, your state health department can provide site-specific guidance. EPA maintains a community involvement program for most NPL sites, and site documents — including the Record of Decision, five-year reviews, and public health assessments — are typically available through EPA's Superfund site profile.