ORNLERASE - EPA REGIONAL SCREENING LEVELS FALL 2024 THQ=1.0

The Regional Screening Levels (RSL) tables are a comprehensive resource developed by the U.S. Environmental Protection Agency (EPA) in collaboration with Oak Ridge National Laboratory (ORNL). It consolidates previous screening tables from multiple EPA regions into a unified platform, now serving as the primary source for screening levels across all EPA regions.

Designed to support Remedial Project Managers (RPMs), On-Scene Coordinators (OSCs), risk assessors, and other decision-makers, the website provides standardized screening tables and a dynamic calculator. These tools assist in evaluating contamination levels at CERCLA (Superfund) hazardous waste sites to determine if further investigation is warranted. While applicable to various programs, users should carefully consider the underlying assumptions to appropriately apply the screening levels (SLs).

The RSLs represent chemical-specific concentrations in air, drinking water, and soil that, if exceeded, may signal the need for additional analysis. The calculator can generate both default and site-specific concentrations for contaminants in soil, air, water, and sediment. SLs are particularly valuable during early project phases, such as Remedial Investigation (RI) scoping and chemical screening. However, these levels are not cleanup standards and should not be misconstrued as final remediation goals.

This tool integrates risk-based screening level equations, considering both carcinogenic and systemic toxicities of chemicals. Default tables address exposure scenarios for residential soil, outdoor worker soil, indoor air (residential and worker), and tap water. The SLs are derived using default exposure parameters and incorporate Reasonable Maximum Exposure (RME) conditions, ensuring standardized and reliable results for early-stage site assessment and planning.