Skip to main content

Hazard Ranking System

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.

[Liz Swain ]

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Hazard Ranking System." Environmental Encyclopedia. . Encyclopedia.com. 13 Nov. 2018 <https://www.encyclopedia.com>.

"Hazard Ranking System." Environmental Encyclopedia. . Encyclopedia.com. (November 13, 2018). https://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/hazard-ranking-system

"Hazard Ranking System." Environmental Encyclopedia. . Retrieved November 13, 2018 from Encyclopedia.com: https://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/hazard-ranking-system

Learn more about citation styles

Citation styles

Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

http://www.mla.org/style

The Chicago Manual of Style

http://www.chicagomanualofstyle.org/tools_citationguide.html

American Psychological Association

http://apastyle.apa.org/

Notes:
  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.