The purpose of an initial investigation is to determine whether hazardous substances may have been released into the environment on the site in amounts that warrant further action under the Washington State Model Toxics Control Act (MTCA). MTCA is the law that deals with contamination in Washington. Ecology requests an Initial Investigation in response to a complaint from the public regarding possible contamination.
Investigations can also be started when a business notifies Ecology of a hazardous material spill at the business location. The initial investigation helps us decide if the site should go back to Ecology for immediate action, should proceed through a Site Hazard Assessment, or be designated as a “no further action” site. A written report is prepared for each investigation. Investigations include site visits, data gathering, historical research, and possible analytical sampling, or testing at the site.
The Environmental Health Division’s Site Hazard Assessment (SHA) team conducts SHA’s at sites listed on Ecology’s Confirmed and Suspected Contaminated Sites list that are awaiting an SHA.
Sites in King County typically are former or current light industrial businesses, though residences can also be on the list. Typical sites include:
- Dry cleaners
- Auto wrecking yards
- Auto repair shops
- Construction companies
- Manufacturing facilities
- Abandon landfills
- Private residences
Sites receive a hazard ranking (from 1 to 5) using the Washington Ranking Method. Sites ranked a 1 are the most contaminated and 5 are the least contaminated. If the site shows no contamination, they will be recommended for a “No Further Action” status and are removed from the list. Sites that are ranked will be added to the Confirmed and Suspected Contaminated Sites list for follow up “remedial action,” or clean up, under the Model Toxics Control Act.
A Site Hazard Assessment is not intended to completely analyze every aspect of the site’s contamination, but must include enough information to determine if the site will be ranked or not. The following is a summary of what Public Health staff do during a Site Hazard Assessment:
- Conduct comprehensive review of any files associated with the property, conduct interviews with those most familiar with the site’s history, and gather other relevant data;
- Prepare a health and safety plan for each site;
- Conduct initial site visits in preparation of sampling;
- Prepare a detailed site map for each site, including all structures, wells, drainfields, utilities, vegetative areas, paved areas, and waste storage areas. Delineate sampling locations;
- Prepare a sampling and analysis plan for each site;
- Conduct sampling of surface water, groundwater, soil and sediment as necessary;
- Analyze samples for suspected contaminants in the laboratory;
- Compile all relevant data into data collection summary sheets and determine a hazard ranking using the Washington Ranking Method; and
- Prepare a final report for each site that includes a ranking recommendation and provide to Ecology.
Once a site has been ranked by the Site Hazard Assessment team, all of the information collected during the SHA is forwarded to Ecology. The contaminated site is then assigned an Ecology site manager who will track the status of the site until the contamination is removed.