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Likelihood of Release

HRS Rule, Section 2.3, page 51589:

  • The likelihood of release factor category measures the likelihood that a hazardous substance has been or will be released to the environment. The likelihood of exposure factor category measures the likelihood that individuals will come directly into contact with hazardous substances.
  • Likelihood of release has the same structure in all three migration pathways.
  • Either an observed release is documented or the potential to release factors are evaluated.
  • An observed release is assigned the maximum value for likelihood of release (550 points).
  • An observed release can be documented either by "chemical analysis" of environmental samples or by "direct observation" of substances entering the ground water, surface water, or air.
  • If an observed release cannot be documented, then the potential to release factors are evaluated.
  • Potential to release is assigned a value of between 0 to 500 points.
  • Potential to release is generally evaluated based on the product of source characteristics and source containment factors.
    • The source characteristics factors reflect the physical and environmental characteristics of the source and its location that influence the likelihood of release from the source in the absence of man-made barriers.
    • The containment factors represent the physical characteristics of the man-made barriers at the source that lessen the likelihood of release.

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