Tier I/II Designation and Screening Process Summary

Introduction/Purpose
This document summarizes EPA's Tier I and Tier II definitions and screening process for sites being addressed through voluntary cleanup programs. Tier I sites are among those where EPA has historically taken cleanup actions under the Federal Superfund program. Tier II sites are generally representative of those where EPA has not historically taken Federal Superfund cleanup actions. EPA intends that any party can use the process outlined below to make Tier I/II designations. Understanding the potential for Superfund involvement enables stakeholders to make more informed property cleanup, transfer, and redevelopment decisions.

Defining Tier I and Tier II Sites
Tier I sites are those that have greater potential to require long-term or emergency cleanup work under the Federal Superfund program. These are sites which have a release of a hazardous substance, pollutant, or contaminant that has caused, or is likely to cause, human exposure or contamination of a sensitive environment. These sites typically involve contamination of drinking water, surface water, air, or soils which has either caused, or is likely to cause, exposure to nearby populations, or has contaminated, or is likely to contaminate, sensitive environments (such as wetlands, national parks, and habitats of endangered species, etc). Tier II sites are those that have less potential to require long-term or emergency cleanup work under the Federal Superfund program. This includes sites which: 1) do not qualify for response under Superfund (e.g., CERCLA petroleum exclusion sites); 2) score below 28.5 based on EPA's Hazard Ranking System (HRS), 55 FR 51532; 3) are being adequately addressed under other Federal statutes, subject to the restrictions specified in Section III. A. "Scope and Applicability" of the MOA/VCP guidance document; or 4) otherwise do not meet the criteria given above for Tier I sites.

Screening Process
To conserve resources, EPA has employed a phased, progressively more detailed screening process to identify Federal Superfund sites. Key factors in making decisions about sites include whether a release of hazardous substances has occurred or is likely to occur and determining whether people or sensitive environments have been or are likely to be impacted by the release. Only about 15 percent of the sites screened by Superfund to date have required removal or remedial actions - most are screened out. The Superfund screening process differs from the private sector site evaluation approach which typically is interested in what environmental liabilities and remediation costs are associated with a site or property. Consequently, the private sector assessments focus on collecting information on the property, not offsite impacts. The Tier I/II screening process outlined below uses common elements of both approaches and incorporates, when necessary, the data needed for EPA to ensure human health and environmental issues are addressed.

The five major steps in making a Tier I/II determination include: 1) Exclusions; 2) Phase I; 3) Expanded Phase I; 4) Limited Sampling; and 5) Extensive Sampling. Each step in the process involves gathering sufficient information about a site and/or it's environs to determine whether the site should be classified as Tier II or continue on to the next step for additional information. Sites continuing in the process may ultimately reach the final step, Extensive Sampling, which results in either a Tier I or Tier II determination; however, a site should be classified as Tier I at any step in this process if information indicates a release of a hazardous substance, pollutant, or contaminant has caused, or is likely to cause, human exposure or contamination of a sensitive environment.

EPA's HRS model can also be applied at any point in the assessment process to assist parties in determining the likelihood of Federal Superfund interest. Sites with an HRS score below 28.5 are considered Tier II by the Agency and account for most of the sites assessed under Superfund.

The steps involved in making a Tier I/II determination are further described in the Screening Process section of the Tier I/II Designation and Screening Process document.

Conclusion
EPA believes the screening process described above can by used by any party to determine whether a site, in most cases, would be Tier I or Tier II. It enables parties to make many Tier I or Tier II designations based on information collected as part of the private due diligence process. Additional detail can be found in the attachment entitled "Tier I/II Designation and Screening Process."

DRAFT - July 31, 1997