Finding Potentially Responsible Parties (PRP)

Early in the cleanup process, EPA conducts a search to find all of the potentially responsible parties (PRPs). EPA looks for evidence to determine liability by matching wastes found at the site with parties that may have contributed wastes to the site. EPA uses many approaches to do this research, including:

  • Reviewing documents,
  • Site investigation and sampling,
  • Interviews,
  • Using "information request letters" to gather information,
  • Title searches, and
  • Research on the internet and at libraries, courthouses, and state offices.

In addition to identifying PRPs, EPA tries to determine early on:

  • The nature of a party's involvement (e.g., owner, generator),
  • A party's potential defenses (e.g., 3rd party defense),
  • Any applicable exemptions or exclusions,
  • The amount of waste a party contributed, and
  • Whether the party can pay only very little or nothing at all toward the cleanup.

Under EPA's Enforcement First for Remedial Actions at Superfund Sites ("Enforcement First" policy), EPA will usually ask PRPs to conduct the investigation and to perform the cleanup before using Superfund money.

Issuing information request letters is a basic component of nearly all PRP searches. The letters are used for information gathering purposes and do not designate an entity as a potentially responsible party.

PRP Search Manual

Cover of PRP Search Manual

EPA's "PRP Search Manual" (2009) provides guidance on how to search for PRPs that may be liable for cleanup at a Superfund site. The manual, divided into four chapters, 13 appendices, and one addendum (2011), gives the user historical background on Superfund and its enforcement program and describes the planning stages, baseline tasks and followup tasks for conducting effective PRP searches.

Download the complete print edition of the 2009 PRP Search Manual (including 2011 addendum).

Learn More about finding PRPs:

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