Study Shows Positive Impact of
ASTM Risk-Based Corrective Action
by John A. Connor
In 1998, a study was undertaken to determine if use of the ASTM
risk-based corrective action (RBCA) standards by state environmental
agencies resulted in more effective management of leaking underground
storage tanks. The results of the study are a resounding yes.
John Connor, president of the company that conducted the study
for ASTM and USEPA, describes the bottom-line value of these ASTM
management standards as quantified in the study.
RESULTS of a nationwide study show that the ASTM guidelines for
risk-based corrective action (RBCA) have helped state environmental
agencies manage environmental cleanups more effectively through
faster case processing rates, reduced environmental cleanup costs,
and more effective targeting of resources toward higher-risk sites.
The ASTM standard E 1739, Guide for Risk-Based Corrective Action Applied at Petroleum
Release Sites, provides a risk-based framework for assessment
and remediation of soil and groundwater impacted by petroleum.
ASTM standard E 2081, Guide for Risk-Based Corrective Action, provides a risk-based
framework for assessment and remediation of soil and groundwater
impacted by any chemical including, but not limited to, petroleum.
With strong support from the U.S. Environmental Protection Agency
(USEPA), the RBCA process has been adopted by many state agencies
in an effort to improve the management of environmental cleanup
efforts, as needed to address increasing case backlogs and rising
costs associated with remediation of leaking underground storage
tank (LUST) sites. To evaluate the impact of the ASTM RBCA standards,
the Risk-Based Decision-Making (RBDM) Performance Assessment Study,
funded by the USEPA Office of Underground Storage Tanks (OUST)
under an assistance agreement to ASTM, involved detailed evaluation
of five state RBCA regulatory programs. The study was conducted
by Groundwater Services, Inc. (GSI), of Houston, Texas, and is
documented in two recently released ASTM Technical Bulletins. This article provides background on the RBCA standards and reviews
the procedures and results of this study.
Management Challenges Posed by Leaking Underground Storage Tank
State and federal environmental regulations require owners and
operators of underground storage tank facilities to investigate
and remediate spills of petroleum products to the underlying soil
and groundwater. Such fuel leaks can pose a concern with regard
to impacts on drinking water resources, as well as direct exposure
to contaminated soils or vapors. USEPA estimates that over 1 million
underground storage tanks have been in service in the United States,
principally used for fuel storage at gasoline service stations.
Of these, over 400,000 leaking underground storage tank (LUST)
sites have been identified to date, with new releases reported
at rates of 500 to 1000 per week over the past decade. State environmental
regulatory agencies have worked hard to oversee the proper investigation
and cleanup of LUST sites, completing over 240,000 case closures
nationwide. Nevertheless, over 160,000 LUST sites remain to be
completed, and new releases continue to be reported at a rate
of approximately 20,000 per year, posing a chronic backlog and
typical caseloads of 50 to 500 LUST sites per agency staff member.
At a median cost of over $100,000 to investigate and remediate
each LUST site, this cleanup effort represents a multi-billion
dollar expense on a nationwide basis. To offset the financial
burden of LUST cleanups for site owners and operators, 48 states
have established assurance funds, providing partial to full reimbursement
for corrective action expenditures at eligible sites. However,
throughout the past decade, claims have consistently exceeded
available fund revenues, posing a chronic financial crisis for
many states and, in some cases, leading to fund insolvency. In
response, many states are phasing out their assurance funds and/or
seeking to reduce LUST expenditures through more stringent cost
control measures, reduced reimbursement levels, and more cost-effective
cleanup policies. In all cases, however, state environmental agencies
are working to achieve such cost controls without compromising
protection of public health and the environment.
Development and Use of the ASTM RBCA Standard
To address the challenges posed by remediation of an ever-growing
population of LUST sites, in 1993, ASTM Subcommittee E50.01 on
Storage Tanks (part of Committee E50 on Environmental Assessment) began work on the development of
a streamlined process for assessment and response to subsurface
contamination problems. The subcommittee, composed of representatives
from USEPA, state regulatory agencies, major oil companies, banking
and insurance companies, academia, and environmental consulting
firms, identified a risk-based approach as the key to effective
LUST site remediation. ASTM E 1739 integrates risk assessment
practices with traditional site assessment and remedy selection
activities to determine cost-effective measures for protection
of public health and the environment. E 2081 is a companion to
E 1739 in that it addresses chemicals other than petroleum.
The ASTM RBCA process is a flexible, science-based, decision management
framework that may be customized for use by individual regulatory
agencies. In simple terms, the RBCA process entails: 1) identification
of applicable risk factors on a site-specific basis and 2) implementation
of appropriate corrective measures in a timeframe necessary to
prevent unsafe conditions. As defined in the ASTM standards, the
RBCA process involves three key elements:
Risk-Based Site Prioritization: Characterize risk drivers at each site and prioritize response
actions based on the timing and magnitude of potential impacts
to human health and the environment.
Site-Specific, Risk-Based Remediation Goals: Determine risk-based concentration limits for affected environmental
media designed to prevent impacts on human health and the environment.
To provide for economical use at both small and large facilities,
RBCA employs a tiered approach to the development of risk-based
cleanup goals, designed to match the site assessment effort to
the relative complexity of each site. Tier 1 remediation goals
represent generic concentration limits, based on conservative
default assumptions. Under Tiers 2 and 3, the user may derive
site-specific concentration limits, based on additional site data
and increasingly sophisticated methods of data analysis.
Remedy Selection: Minimize risk by preventing exposure to unsafe levels of site
chemicals. Options for management of contaminated soil and groundwater
include removal/ treatment, containment, natural attenuation,
institutional controls, or some combination thereof.
In 1996, USEPA OUST, through a cooperative agreement with ASTM
and public-private partnership organization known as Partners
in RBCA Implementation (PIRI), initiated a nationwide RBCA Training
Program designed to familiarize state regulatory agencies with
the ASTM RBCA framework and support development of state RBCA
regulatory programs customized to local needs. Today, over 43
states have received ASTM RBCA training, 25 states are in the
process of developing RBCA regulatory programs, and 16 states
have RBCA programs in place.
The RBCA Performance Assessment Study: Objectives and Procedures
States implementing RBCA regulatory programs share the common
goal of protecting human health and the environment from impacts
associated with releases from LUST sites. Toward this end, the
specific program management goals identified by these state agencies
Risk Reduction: Reduce risks posed to human health and the environment by releases
from LUST sites.
Expedited Site Evaluation, Remediation, and Closure: Streamline the site assessment process to expedite the remediation
of sites posing significant concerns and close cases presenting
no significant risks.
Cost Control/Resource Allocation: Without compromising protection of human health and the environment,
reduce the cost of the corrective action program by streamlining
the report submittal/review process, targeting resources toward
higher-risk sites, and reducing administrative oversight costs.
In order to measure the progress of state RBCA programs toward
achieving these management goals, the RBDM Performance Assessment
Study was initiated in December 1997 under a cooperative agreement
between USEPA OUST and ASTM. Groundwater Services, Inc., was selected
to conduct this evaluation with three principal objectives: 1)
develop practical, quantitative measures for evaluating the impact
of RBCA on achieving state agency management goals, 2) apply these
measures to five state RBCA agencies to evaluate program performance,
and 3) provide general guidelines for other state or territorial
environmental agencies interested in tracking the benefits of
their RBCA programs.
Five state environmental regulatory agencies (Illinois, Iowa,
North Carolina, Texas, and Utah) that had previously implemented
RBCA programs, volunteered to participate as RBCA pilot states
for the purpose of this study. These five states provide a broad
geographic distribution (e.g., no more than one state per USEPA
Region) and represent a variety of state-customized RBCA programs.
For this study, each state provided access to their LUST case
database and other information used to record the progress of
remediation sites through the regulatory process. In addition,
the pilot states provided input on the goals of their individual
programs, the performance measures currently utilized in their
state, and the utility and feasibility of the RBCA performance
criteria developed for this study.
In order to evaluate the impact of RBCA, GSI compiled individual
state data into a Microsoft Access© database and programmed queries
to characterize trends in these performance metrics over the period
of 1990 through 1999, encompassing the time period before and
after RBCA was implemented in each state. Pre-RBCA and post-RBCA
trends were then compared to identify changes in case backlog,
processing rates, and other key performance parameters.
Key Findings of the Performance Assessment Study
In addition to the data from the five pilot states, related information
was also obtained from the Michigan Department of Environmental
Quality (DEQ), Storage Tank Division, which conducted an independent
audit of their RBCA program. The results of this study support
the following general findings with regard to the common program
Expedited Site Evaluation, Remediation, and Closure: Immediately following implementation of their RBCA program, four
of the five pilot states observed a dramatic increase in case
closures per year and a stabilization or decrease in case backlog.
For example, in the first year of the Utah RBCA Tier 1 program
(1995), the number of case closures increased by 120%, indicating
that a Tier 1 process of generic screening criteria can significantly
impact program performance. In Iowa, 77% of RBCA Tier 1 and 28%
of Tier 2 site assessments resulted in case closure, indicating
that the RBCA process has been effective at identifying sites
for closure or remediation. In general, following RBCA implementation,
the average age of a LUST case at the time of case closure was
observed to increase, which, in combination with the increase
in case closure rates, indicates that many older cases that have
been in the regulatory process for many years are now being addressed.
Risk Reduction: Available information regarding risk-based site classification
(Texas and North Carolina) indicates that most of the LUST site
cases closed by these state RBCA programs are low-risk sites.
These data suggest that RBCA programs are effectively meeting
the state program objective of closing low-risk cases while retaining
higher-risk cases for further evaluation and/or remediation.
Cost Control/Resource Allocation: Cost data in the LUST site databases provided by the pilot states
were not sufficient to measure the cost impacts of RBCA programs
at this time. However, the significant reductions in case backlog
reported by some states clearly correspond to reduced program
cost liabilities. An internal cost survey was conducted by the
Texas Natural Resource Conservation Commission to determine the
impact of RBCA implementation on the cost of site remediation.
Between 1994 and 1998, LUST site remediation/closure costs were
reduced by 70% for soil-impact-only sites (median cost reduced
to $24,000/site from $80,000/site) and by 58% for low-risk groundwater
impact sites (median cost reduced to $107,000 from $250,000/site).
In addition to the five pilot states evaluated for this study,
the Michigan Department of Environmental Quality (DEQ) Storage
Tank Division, has independently evaluated the performance of
their LUST management program following the implementation of
RBCA in April 1995. In 1996, Michigan DEQ reported a 61% increase
in LUST case closures compared to the average case closure rate
for 1990 to 1995. In addition, Michigan DEQ achieved a 30% decrease
in case backlog from 1995 to 1998. Implementation of the RBCA
program resulted in a 24% average reduction in remediation/closure
costs for UST sites, representing a $39,000 cost savings per site
(Michigan DEQ, 1996).
The results of the RBDM Performance Assessment Study clearly demonstrate
the benefits of the ASTM RBCA standards to state environmental
regulatory agencies in terms of more cost-effective management
of environmental impacts associated with LUST sites. In the majority
of pilot states, implementation of a RBCA program resulted in
an immediate increase in LUST case closures and a stabilization
or decrease in case backlog. Such backlog reductions represent
a decreased administrative burden for the agency as well as a
substantial reduction in cost liabilities, allowing staff and
funding resources to be focused on remediation of higher-risk
sites. In addition, RBCA was found to target low-risk sites for
closure, while retaining higher-risk for further action, which
is consistent with the objective of streamlining the corrective
action process without compromising protection of human health
and the environment.
State environmental agencies, with support from USEPA, have made
significant progress toward assessing and remediating the over
400,000 LUST cases reported to date nationwide. However, over
160,000 known LUST sites remain to be addressed, and new releases
continue to be reported at a rate of approximately 20,000 per
year. As state financial assurance programs are phased out in
coming years, remediation costs will increasingly shift to tank
owners and operators or other insurance mechanisms. Consequently,
cost-effective management of LUST sites will remain a critical
need for years to come, and regulatory agencies may continue to
look to ASTM RBCA as an effective model for addressing this challenge.
The study was funded by the United States Environmental Protection
Agency (USEPA) Office of Underground Storage Tanks (OUST) under
Assistance Agreement #X825708-01 to the American Society for Testing
and Materials (ASTM). Groundwater Services, Inc. (GSI), of Houston,
Texas, conducted the study. Richard Mattick, USEPA OUST project
manager, provided oversight and review of this study. In addition,
we would like to thank the participating states, USEPA regions,
and the Partnership in RBCA Implementation (PIRI) for their support
Copyright 2000, ASTM