Hazard Ranking System Encyclopedia Article

Hazard Ranking System

The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.

(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.

The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.

The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.

All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.

Hazard Ranking System


The Hazard ranking system (HRS) is a numerical scoring procedure that the federal Environmental Protection Agency (EPA) uses to place and prioritize waste sites on the National Priorities List. Only these priority sites can be cleaned up through the Superfund Trust Fund program.

The HRS score is based on an evaluation of threats related to the release or potential release of hazardous substances. The HRS assessment of a site ranks public health factors such as threats to drinking water, the food chain, and populations exposed through occupational and ambient environments. Also evaluated are environmental threats like the effect of substances on air quality, resources, and sensitive ecosystems.

Federal investigators score a site by evaluating four pathways that could be affected by hazardous releases. The pathways are ground water migration, surface water migration, air migration, and soil exposure.

The pathway scores are combined using a root-mean-square equation. This calculation produces the overall score for a site. A high HRS score does not guarantee immediate action because clean-up work may be going on at other sites. The decision to take action on a site is based on additional research that includes a remedial investigation of what corrective action is needed.