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hazardous ranking system HRS

The hazardous ranking system is the principle screening tool used by the Environmental Protection Agency (EPA) to evaluate risks to public health and the environment associated with abandoned or uncontrolled hazardous waste sites.

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The HRS calculates a score based on the potential of hazardous substances spreading from the site through the air, surface water, or groundwater and on other factors such as density and proximity of human population. This score is the primary factor in deciding if the site should be on the National Priorities List (NPL) and, if so, what ranking it should have compared to other sites on the list.