Assessing contaminated sites

Contamination at a site can be in environmental media like soil, groundwater, surface water, sediment, and indoor air. The SHARP tool asks a series of questions about each media, then uses the answers to score the potential chemical exposure and its severity. Tracking them separately gives us the ability to focus on specific issues, like clean drinking water.

• Exposure
  The exposure score answers the question, “How likely are people or other living things to be exposed to the contamination at this site?” It’s graded A to D, where A means “there is a known exposure happening right now,” and D means “there’s no likely way for people or other living things to be exposed to this contamination.”

• Severity
  The severity score is an estimate of how risky an exposure would be if people or other living things were exposed. It’s estimated on a scale of 1 to 4, where 1 is the most severe and 4 is the least.

Overall site rating

We combine the five scores into an over-all rating of low, medium, high, or critical. The rating gives the most weight to known exposures. It’s an at-a-glance estimate of a site’s risk. The scores, rating, and other information about the site are displayed in a text report with a graphic summary.

If a site has a SHARP report, it will be on the cleanup site webpage. You can use our map or database to find cleanup sites.

More than just scores

These five media scores give us a picture of what and where contamination is at a site, but they’re not the only information included in a SHARP report.

Confidence: rating how much we know

Often, our initial information about a site is very limited. For instance, we might know of a chemical spill on soil but not know what the chemical was. The SHARP reports include confidence scores to show where we might need more information.

Context: seeing a bigger picture

SHARP also alerts us to factors that aren’t part of scoring, including:

• Information about local communities

• Risks of flooding, wildfires, and other impacts from climate change at the site

• Other pollution issues

Environmental Equity 

As part of the assessment we determine whether the population threatened by a contaminated site includes a vulnerable population or overburdened community. We use data from the Washington Environmental Health Disparities map and site-specific information to learn about the surrounding communities. This helps us to prioritize our work and support environmental equity across Washington. 

If we determine there is a likely vulnerable population or overburdened community threatened by a contaminated site, the SHARP report is marked with an “EJ flag.”

How we use SHARP results

We use SHARP ratings to:

• Support decisions to add or remove sites from the Contaminated Sites List and the No Further Action Sites List.
• Prioritize remedial actions and allocate agency resources.
• Inform the public and legislature about risks posed by contaminated sites.
• Track progress and reflect changes in site risks, based on new information or changes in site conditions.
• Identify whether the potentially impacted community includes a likely vulnerable population or overburdened community.

We assess every new site added to the Contaminated Sites List. We are also working on rating over 6,000 sites that are already on the list. We hope to assess the majority of sites by 2030. We may reassess current sites as appropriate, such as when we receive information about changed site conditions or completed cleanup activities.