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Toxics Cleanup Program

Area-wide Soil Contamination Project History

Photo:  Aerial view of the old Tacoma Smelter PlumeArea-wide soil contamination is low-to-moderate arsenic and lead soil contamination spread over a large area.  The area could range from several hundred acres to many square miles.  In Washington State, area-wide contamination comes from three main historical sources:

  • Emissions from metal smelters in Everett and Tacoma.
  • Use of arsenical pesticides, especially on orchards.
  •  Combustion of leaded gasoline. 

Area-Wide Soil Contamination Toolbox

This toolbox provides background on how Ecology is addressing area-wide arsenic and lead.  The Area-Wide Soil Contamination Task Force helped to develop these maps and tools.  Please note that this is historical information and may not be up-to-date.

  • Background information on area-wide soil contamination.

  • Maps and other information describing the location and extent of area-wide soil contamination in Washington.  This information is organized according to the three main sources of area-wide soil contamination:
    • historical emissions from metal smelters located in Tacoma, Harbor Island, Everett, Northport, and Trail, BC;
    • historical use of lead arsenate pesticides on apple and pear trees; and
    • emissions from combustion of leaded gasoline.  
  • Tools for conducting individual property evaluations to determine whether there is the potential for exposure to elevated levels of lead and arsenic in soil.  These tools include:
    • Individual Property Evaluation Flowchart – to determine whether arsenic and lead soil contamination is likely to be present in soil on a property using information about the property’s location and its land-use and development history,
    • Qualitative Evaluation Checklist for Understanding Potential Exposures to Arsenic and Lead in Soil – to determine whether there is potential exposure on the property and inform decisions about whether to test soils and/or implement protection measures to reduce potential exposure, and
    • Sampling Guidance – to provide instructions for how to collect and analyze soil samples for arsenic and lead at three types of land uses: child-use areas, residential properties, and commercial properties.
    Photo: old container arsenate of ead
  • Information on health risks from exposure to low-to-moderate levels of arsenic and lead in soil.  
  • Examples of individual protection measures that individuals can use to limit potential exposure to arsenic and lead in soil.  In particular, individual protection measures are designed to minimize the potential for exposure of children, gardeners, and other adults who frequently work in soil.  This toolbox contains four sets of example practices:
    • Personal hygiene practices and other guidelines for how residents may reduce potential exposure, developed by Public Health – Seattle & King County
    • Actions that schools may use to reduce potential exposure of schoolchildren, developed by the Tacoma-Pierce County Health Department
    • Worker protection guidelines, developed by the Snohomish Health District for the Everett smelter area
    • Guidelines for gardening on soils that may contain elevated levels of arsenic and lead, developed by the Washington State University, Agricultural Extension

  • Information describing the range of protective measures that might be taken to respond to area-wide soil contamination and providing guidance on how to implement those protective measures in an effective, practical, and affordable manner.  

History of the Area-Wide Soil Contamination Task Force

In the early 2000’s, the State of Washington brought together a task force to develop a strategy for dealing with “area-wide” soil contamination.  In 2003, the task force put out a report with their recommendations.  Ideas included educating the public, protecting children, and cleaning up areas of highest contamination. 

Ecology is using many of these ideas for the Tacoma Smelter Plume , the Everett Smelter , and at schools built on former orchard lands.

Contact information for Federal, State, and local agencies that are available to answer questions and provide additional help.