Risk-based decision making for site cleanup

              Risk Based Decision Making • June 2013 • Page 1 of 7
The Oklahoma Department of Environmental Quality
(DEQ) has adopted a risk based decision making
process to provide a framework for determining
cleanup requirements at contaminated sites. This
process ensures that DEQ’s cleanup decisions are
protective of human health and the environment.
Risk based decision making is a tool that ensures
contaminated properties are adequately addressed.
DEQ uses risk based decision making to oversee
remediation of contaminated properties and ensure
that cleanups are protective, all Applicable or
Relevant and Appropriate Requirements (ARARs) are
evaluated, and cleanup is accomplished in a practical
and effective manner. Risk based decision making
allows properties to be returned to productive reuse.
DEQ uses risk based decision making for cleanups
conducted under the Comprehensive Environmental
Response, Compensation and Liability Act (CERCLA),
Resource Conservation and Recovery Act (RCRA),
Oklahoma Voluntary Clean-Up Program (VCP), and
the Oklahoma Brownfields Voluntary Redevelopment
Act. DEQ is committed to the application of
consistent decision making to determine the level of
cleanup that needs to occur at a site.
What is Risk Based Decision
Making?
Risk based decision making involves evaluating actual
and potential risks posed by a contaminated site in
order to make responsible and practical decisions to
mitigate those risks. The process includes identifying
hazards, assessing exposure, assessing toxicity,
characterizing the risk, and making an informed
decision. Risk based decision making cannot be
fully utilized without adequate site characterization.
Adequate site characterization includes sampling
an adequate list of analytes to effectively determine
the nature and extent of contamination. The DEQ
typically requires minimum analysis for volatile organic
compounds (VOCs), semi-volatile organic compounds
(SVOCs), metals and total petroleum hydrocarbons
(TPH) to adequately characterize a contaminated site
and determine the chemicals of concern. Additional
analyses may be required if the history of the site
suggests other chemicals may be present.
Risk based decision making is not appropriate when
immediate risks are recognized (i.e spills) or waste
is present. Immediate risks and observable waste
should be addressed by prompt actions that protect
human health and the environment.
General Requirements for Risk
Decisions
Information about the property is needed to make
informed decisions about the environmental risks to
the community and future occupants. In general, the
following must be evaluated:
1. Data Quality Objectives (DQOs):
a. DQOs are quantitative or qualitative
statements developed in the planning stage
to define the goals of data collection. DQOs
guide the project and ensure the data
collected is usable, sufficient, and exhibits
the quality necessary to make cleanup
decisions. DQOs are established in the
Quality Assurance Project Plan or Work Plan
for the site.
b. The DEQ requires that data be suitable to
perform an evaluation of risk. DEQ will
consider, but will not always accept, data that
is collected outside its oversight. If data is
more than two years old, further sampling and
analysis may be required.
July 2013
Risk-Based Decision Making for Site Cleanup