905R91108
SEPA
United States
Environmental Protection
Agency
Office of Publication 9200.5-2161
Solid Waste and DCV»-* *"*.«4uly.l991
Emergency Response
Superfund
Records of
Update
201991
Office of Emergency and Remedial Response
Hazardous Site Control Division OS - 220W
Intermittent Bulletin
Volume 6 Number 3
This issue of the ROD Update summarizes recent policy concerning the baseline risk assessment and the delisting
process. A current list of Regional Coordinators for both Fund Lead and Enforcement Lead sites is also provided.
ROLE OF THE BASELINE RISK
ASSESSMENT IN SUPERFUND REMEDY
SELECTION DECISIONS
The Office of Solid Waste and Emergency Response
(OSWER) recently issued a policy directive titled Role
of the Baseline Risk Assessment in Superfund Remedy
Selection Decisions (OSWER Directive 9355.0-30, April
22, 1991). The directive provides clarification con-
cerning the role of the baseline risk assessment in the
development of Superfund remedial alternatives and
supporting risk management decisions. The memo-
randum discusses how to use the baseline risk assess-
ment in determining whether remedial action under
CERCLA Section 104 or Section 106 is warranted and
clarifies the use of the baseline risk assessment in
selecting appropriate remedies under CERCLA Sec-
tion 121. The directive also discusses technical factors
and information about consistency in preparing site-
specific risk assessments, and provides guidance for
presenting appropriate documentation from the
baseline risk assessment in Superfund remedy se-
lection documents.
The primary purpose of the baseline risk assessment
is to provide a quantitative and qualitative under-
standing of the actual and potential risks to human
health and the environment posed by the site and the
uncertainties associated with the assessment.
Risks Warranting Remedial Action
EPA generally uses the results of the baseline risk
ssessment to establish the basis for taking a remedial
action using either Section 104 or Section 106 author-
ity. EPA may use the results of the baseline risk
assessment to determine whether a release or threat-
ened release poses a risk to human health or the
environment that warrants remedial action and to
determine if a site presents an imminent and sub-
stantial endangerment.
Generally, where the baseline risk assessment indi-
cates that a cumulative site risk to an individual using
reasonable maximum exposure assumptions for ei-
ther current or future land use exceeds the 10~4 lifetime
excess cancer risk end of the risk range, action under
CERCLA is generally warranted at the site. For sites
where the cumulative site risk to an individual based
on reasonable maximum exposure for both current
and future land use is less than 10'4, action generally
is not warranted, but may be warranted if a chemical-
specific standard that defines acceptable risk is vio-
lated or unless there are non-carcinogenic effects or
an adverse environmental impact that warrant action.
A risk manager may also decide that a lower level of
risk to human health is unacceptable and that remedial
action is warranted where, for example, there are
uncertainties in the risk assessment results.
The cumulative site baseline risk should include all
media that the reasonable maximum exposure sce-
nario indicates are appropriate to combine and should
not assume that institutional controls or fences will
account for risk reduction. For non-carcinogenic ef-
fects of toxicants, unacceptable risk occurs when
exposures exceed levels which represent concentra-
tions to which the human population, including
sensitive subgroups, may be exposed without ad-
verse effect during a lifetime or part of a lifetime, as
appropriate to address teratogenic and developmen-
tal effects.
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Chemical-specific standards which define acceptable
risk levels, e.g., non-zero MCLGs, MCLs, also may be
used to determine whether an exposure is associated
with an unacceptable risk to human health or the
environment, and thus whether remedial action is
supported under Section 104 or Section 106. MCLs
and non-zero MCLGs are generally used in ground
water actions to determine whether remedial action
is triggered.
Unacceptable environmental risks also may prompt
remedial action and may occur where there is no
significant risk to human health. Threats or potential
threats to sensitive habitats, such as wetlands, and
critical habitats of species protected under the En-
dangered Species Act are especially important to
consider when determining whether to take an action
under CERCLA Section 104 or 106. Ambient Water
Quality Criteria for aquatic organisms are chemical-
specific standards that will generally be considered
when determining whether to take an action based on
the environmental risk of releases to surface waters.
Where current conditions have not resulted in a release
posing risks that require action but there is a signifi-
cant possibility that a release will occur that is likely
to result in an unacceptable risk, remedial action also
may be taken. The significance of the potential future
release may be evaluated, in part, based on the
quantities of material at the site and the environmental
setting.
Once a decision has been made to take an action, the
Agency has expressed a preference for cleanups
achieving the more protective end of the range (i.e.,
10~*), although waste management strategies achiev-
ing reductions in site risks anywhere within the risk
range may be deemed acceptable. The remedial ac-
tion must attain applicable or relevant and appropriate
requirements (ARARs) unless a waiver is invoked.
No-Action Decision
If the baseline risk assessment and the comparison of
exposure concentrations to chemical-specific stan-
dards indicates that there is no unacceptable risk to
human health or the environment, and that no re-
medial action is warranted, then the CERCLA Section
121 cleanup standards for selection of a Superfund
remedy including the requirement to meet ARARs
are not triggered. Sites that do not warrant action
under CERCLA Section 104 or Section 106 may war-
rant action under another State or Federal statute.
Point of Departure When Action is Warrante
Once remedial action is determined to be warranted,]
the results of the baseline risk assessment are used iri
establishing remediation goals.
Documentation of Baseline Risk Assessment
Results in the Record of Decision
Records of Decision (RODs) for remedial actions taken
at sites posing risks within the 10"4 to 10~6 risk range
must explain why remedial action is warranted. The
justification for taking action in the risk range 10"4 to
1 0~6 should be included in the discussion of the selected
remedy section of the ROD "Decision Summary,"
where cleanup levels are given. A decision not to take
action at a National Priorities List (NPL) site undei
Sectionl04and Section 106 also should be documented
in the ROD.
The chemical-specific remediation level and corre-
sponding chemical-specific risk level(s) to be attained
at the conclusion of the response action and the points
(or area) of compliance for the media being addressed,
and the basis for the remediation levels including the
risk calculation and ARARs, should be provided ir
the in the discussion of the selected remedy in the
"Decision Summary" section of the ROD. '
A discussion of the risks associated with current anc
future land use should be included in the "Summary
of Site Risks" section of the ROD, and should include
a table presenting these risk levels for each exposure
medium. When risks from exposure via more thar
one medium will affect the same potentially exposec
individual, the risks should be combined to indicate
the total risk posed by the site to that individual.
The "Comparative Analysis of Alternatives" sectior
of the ROD should include a discussion of each of the
nine criteria; consideration of risk is part of the dis
cussion of several of the criteria. The discussion o
overall protection of human health and the environ
ment should include a discussion of how the remedj
will eliminate, reduce, or control risks identified it
the baseline risk assessment posed through eacl
pathway and whether exposure levels will be reducec
to acceptable levels. The discussion of long-term ef
fectiveness and permanence should include, when
appropriate, an assessment of the residual risk fron
untreated residual waste remaining at the site. Thi
short-term effectiveness discussion should addresi
risks during remedial action to those on-site
nearby.
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Documentation of Risk for Interim Action
RODs
Interim action RODs do not require a completed
baseline risk assessment although enough informa-
tion must be available to demonstrate the potential
for risk and justify taking an action. Data sufficient to
support the interim action decision can be extracted
from the ongoing RI/FS for the site and set out in a
focused feasibility study or other appropriate docu-
ment that includes a short analysis of a limited num-
ber of alternatives. These data should include a
summary of contaminants of concern, concentrations
and relevant exposure information. A discussion
should accompany these data explaining the need for
immediate remedial action based on the presence of
contamination that, if left unaddressed in the short-
term, either contributes immediate risk or is likely to
contribute to increased site risk or degradation of the
environment/natural resources.
The interim action should demonstrate qualitatively,
and quantitatively if possible, that there is a risk or
potential for risk and explain how the temporary
measures selected will address a portion of this risk.
Also, the interim action ROD should indicate where
appropriate that some exposure pathways at the site
may not be addressed by the action.
An interim action ROD must be followed by a subse-
quent ROD for that operable unit based on the com-
plete RI/FS, that includes the baseline risk assessment,
in order to document long-term protection of human
health and the environment for that portion of the
site.
Requests for additional guidance on the interaction
between the baseline risk assessment and remedy
selection should be directed to David Cooper (703-
308-8361 or FTS 398-8361) in the Hazardous Site
Control Division, OERR. For guidance specific to
enforcement-lead sites contact Stephen Ells (202-475-
9803 or FTS 475-9803) in the CERCLA Enforcement
Division, OWPE.
DELISTING
Superfund Publication; 9347.3-09FS, September 1990,
A Guide to Delisting of RCRA Wastes for Superfund
Remedial Responses, provides guidance concerning
/vhen to consider delisting a waste; the basis for
delisting; how compliance is demonstrated; and ap-
propriate documentation and sample language for a
waste delisting in the RI/FS, the Proposed Plan, and
the Record of Decision (ROD).
Background
Delisting applies only to listed wastes, mixtures
containing listed wastes, or residuals derived from
treatment of a listed waste. Delisting requires a
demonstration that a listed RCRA hazardous waste,
or a mixture containing listed hazardous wastes, no
longer meets any of the criteria under which the
waste was listed and no other factors are known that
would make the waste hazardous. Characteristic
wastes can meet the land disposal restriction (LDR)
treatment standards or be rendered "non-character-
istic" to be eligible for Subtitle D management.
Only substantive requirements of delisting must be
met for on-site CERCLA actions. The delisting may be
granted when the Regional Administrator signs the
ROD.
Off-site CERCLA actions must comply with both
substantive and administrative requirements and
must follow the formal delisting petition process
when hazardous wastes or waste residuals are to be
delisted for management off-site. These administra-
tive requirements include review by the Office of
Solid Waste (EPA Headquarters) or State review for
those States that have adopted a delisting program at
least equivalent to the Federal Program, publication
of a proposed notice and final rule in the Federal
Register.
When to Consider Delisting
Delisting should be evaluated as a potential option
when remedial actions address materials contami-
nated with RCRA listed waste in low concentrations;
it is believed that these materials pose no significant
threat to ground water; and management in a Subtitle
D solid waste disposal facility would be fully protec-
tive of human health and the environment.
The delisting option should be considered as early as
the site characterization and the development of the
baseline risk assessment if RCRA wastes are at or near
delisting levels. Delisting evaluations should be made
early in the RI/FS process so that requirements and
disposal options related to delisting may be included
in the detailed analysis of remedial alternatives. When
results from treatability studies conducted during the
RI/FS indicate that treatment will attain delisting
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levels, these data may serve as the basis for approving
a delisting demonstration. When site-specific
treatability study data are not available, data from the
application of technologies to similar wastes may be
used to assess the probable effectiveness of the
treatment processes and to demonstrate that a par-
ticular waste would be rendered non-hazardous and
justify a delisting. If site managers believe that techni-
cally sound reasons exist that delisting levels can be
attained, the option to delist wastes can be pursued,
but another option should be specified for disposal of
the waste in case delisting levels cannot be attained.
Basis for Delisting
OERR recommends that for delisting at CERCLA
sites, the same analytical tests and models as those
recommended by the Office of Solid Waste be used.
Regardless of which model is used to analyze and
predict the potential fate and transport of waste con-
stituents and to substantiate a delisting request,
documentation should be made of why a particular
model is used.
Demonstrating Compliance
Verification testing may be required following treat-
ment of the wastes to confirm that delisting levels are
attained. These tests may require collecting samples
generated from treatment systems; analysis of samples
fortotal and TCLPleachate concentrations of inorganic
and organic constituents and other RCRA character-
istics; and analysis of other information relevant to
the delisting that may not have been anticipated or
considered at the time the original decision document
was signed. All data from verification testing must be
collected using the appropriate QA/QC procedures
such as those contained in the site's Quality Assurance
Project Plan (QAPP) prepared during the RI/FS
scoping or remedial design process.
Documenting a Waste Delisting
Although compliance with the RCRA administrative
delisting requirements are not required as part of an
on-site CERCLA remedial response, compliance with
the substantive requirements of delisting must be
documented in the appropriate CERCLA documents.
Since off-site CERCLA responses must comply with
both substantive and administrative requirements,
the formal delisting petition process (40 CFR 260.20
and 260.22) must be followed when hazardous wastes
or waste residuals are to be delisted for management
off-site.
RI/FS, The substantive requirements for delisting a
RCRA hazardous waste should be documented in the
RI/FS. A general discussion of why delisting is
warranted should be included in the "Detailed
Analysis of Alternatives" chapter of the FS Report as
a part of the description of each alternative for which
a delisting is contemplated. Where treatment is ex-
pected to produce a delis table residual, the discussion
should specify the concentrations of each waste
constituent expected to remain after treatment. Wastes
or waste residuals to be delisted and managed under
Subtitle D instead of Subtitle C should be identified in
the "Compliance with ARARs" criterion of the "De-
scription of Alternatives" section of the RI/FS.
Proposed Plan. The intent to delist wastes should be
stated in the "Description of Alternatives" section of
the Proposed Plan. The intent to delist wastes for both
on-site and off-site wastes should be identified for all
alternatives for which delisting is an option. The
opportunity for public comment on the Proposed
Plan fulfills the requirements for public notice and
comment on delisting petitions.
Record of Decision. A synopsis of the documenta-{
tion provided in the FS Report should be included in
the ROD. A statement that explains why delisting is
justified should be included as part of the discussion
of major ARARs for each remedial alternative in the
"Description of Alternatives" section, along with a
statement that the waste is being delisted under
CERCLA and that RCRA's substantive requirements
have been met. A statement that waste(s) is being
delisted should be included in the "Compliance with
ARARs" finding in the "Statutory Determinations"
section of the ROD.
The ROD should also address how to handle wastes
that do not achieve delistable levels unless treatability
studies conducted in the RI/FS indicate that a
technology's performance is reasonably certain. In
other words, the ROD should include a contingency
plan. A discussion in the "Selected Remedy" section
of the ROD should establish the parameters of both
the selected and contingent remedies and provide the
criteria by which the contingency remedy would be
implemented. The "Statutory Determinations" sec-
tion should demonstrate how either remedy would
fulfill CERCLA Section 121 requirements.
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SUPERFUND REGIONAL COORDINATORS
Fund Lead: RI/FS and ROD
Region
1
II
II
III
IV
Region
1
II
III
IV
V
Name FTS No.*
Jennifer Sutler 398-8363
Loren Henning 398-8392
(New Jersey)
Shahid Mahmud 398-8372
(New York)
Sharon Frey 398-8367
Tish Zimmerman 398-8370
Fund and Enforcement
Name FTS No.*
JoAnn Griffith 398-8353
Joe Cocalis 398-8356
Florence Blair 398-8327
Ken Skahn 398-8355
Tracy Loy 398-8349
Region
V
VI
VII
VIII
IX
X
Lead: Design and
Region
VI
VII
VIII
IX
X
Name
Andrea Mclaughlin
Robin Anderson
Tish Zimmerman
Nancy Briscoe
David Cooper
Susan Cange
Construction
Name
Ed Hanlon
Ken Skahn
Barbara McDonough
Steve Chang
Steve Chang
FTS No.*
398-8365
398-8371
398-8370
398-8362
398-8361
398-8360
FTS No.*
398-8352
398-8355
398-8347
398-8348
398-8348
Enforcement Lead: Removals, RI/FS, ROD, RD/RA Negotiations
Region
1
II
111
IV
Name FTS No.*
Amy Legare 398-8626
Lance Elson 398-8621
(New York, New Jersey)
Kathryn Boyle 398-8614
(Virginia, West Virginia)
Wendy Thomi 398-8627
(Pennsylvania)
Elisabeth Freed 398-8608
(Delaware, Maryland,
District of Columbia,
Pennsylvania)
NeilimaSenjalia 398-8630
(Florida, Alabama,
Georgia, Mississippi)
Dariene Boerlage 398-8646
(Kentucky, Tennessee,
North Carolina, South Carolina)
Region
V
VI
VII
VIII
IX
X
Name
Trish Gowland
(Illinois, Indiana)
Ernie Watkins
(Michigan, Wisconsin)
Leslie Jones
(Minnesota, Ohio)
Filomena Chau
Jack Schad
Lori Boughton
Rick Popino
(Site-Specific)
Kurt Lamber
(Site -Specific)
Joe Teiger
FTS No.*
398-8622
398-8633
398-8631
398-8619
398-8629
398-8613
398-8628
398-8624
398-8632
*Note: Commercial No. 703-308-xxxx
For ideas, submissions, or questions concerning the ROD Update, please contact Carol Bass 202/475-9752.
Members of the public may obtain copies by contacting the EPA Superfund Document Center (OS-240),
401M. St., S.W., Washington, DC 20460. Please use fax number 202/245-4386 or E-mail Box 5248 OERR/
PUBS or send a written request to ensure that your order is expedited.
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&EPA
United States
Environmental Protection
Agency (OS-120)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
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