Risk Based Decision Making for the Remediation of Contaminated Sites

NOTE: The Urban/Residential Receptor Scenario is no longer applicable. This, along with updates to RBC values, are expected to be published early fall 2025.

Current guidance documents

Guidance for Risk Based Decision Making for the Remediation of Contaminated Sites
Human Health Risk Assessment Guidance - This document contains DEQ’s 2011 RBC spreadsheets in Appendix C; however, parties should use DEQ’s most recently released RBC spreadsheets
Guidance for Ecological Risk Assessment
Guidance for Assessing and Remediating Vapor Intrusion in Buildings
Frequently Asked Questions for Risk Based Decision Making

Current Risk-Based Concentrations

Generic Risk-Based Concentrations

Table of Risk-Based Concentrations (modified to show the lower of non-carcinogenic and carcinogenic RBCs. These PDF tables should be used unless performing site specific calculations.)
Table of Risk-Based Concentrations Abridged for Tank Program and Heating Oil Tank Program
Trichloroethene Toxicity Values
Vapor Intrusion Risk-Based Concentrations Spreadsheet
Vapor Intrusion Risk-Based Concentrations Table, Chronic
Vapor Intrusion Risk-Based Concentrations Table, Acute

Site-Specific Risk-Based Concentrations

Spreadsheet of Site-specific Risk-Based Concentrations for Individual Chemicals

Notes to Accompany Risk-Based Concentrations for Individual Chemicals Spreadsheet

Calculating RBCs for Total Petroleum Hydrocarbons (please right-click and save the file to your desktop)
Figure 2.2 Conceptual Site Model

Background

Oregon environmental cleanup law and regulations require a risk-based approach for assessing and managing environmental contamination. The Risk Based Decision Making Guidance and associated tables of risk-based concentrations provide a consistent, streamlined decision making process for evaluating risks to human health and the environment. Other models or approaches may be used to evaluate site risks provided they meet risk-based cleanup standards specified in Oregon Revised Statute 465.315.

In March 2024, DEQ published new information on vapor intrusion acute and chronic risk based concentrations. The most recent revisions are summarized below under Update history. Visit the Vapor Intrusion web page for more information

DEQ periodically updates RBCs when EPA makes substantive updates to screening tables. EPA updates its screening table semi-annually. DEQ evaluates those updates to determine how they relate to DEQ’s RBCs. Under special circumstances, DEQ may at any time require a revised screening value for a chemical based on new toxicity information. If a chemical does not have a DEQ RBC, then the EPA regional screening level should be used.

Update history

Applicable regulations

OAR 340-122-0100 through 340-122-0115
Releases of hazardous substances including petroleum under the state’s hazardous substance remedial action rules

Oregon Administrative Rules 340-122-0205 through 340-122-0260
Cleanup of petroleum releases from regulated underground storage tanks under Oregon cleanup rules for Leaking Petroleum Underground Storage Tank Systems.

Contact

For more information, contact the Environmental Cleanup Program contact:

Mike Poulsen
Cleanup Toxicologist
503-229-6773

To submit a report to DEQ, use Your DEQ Online.