UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
APR 13 1998
OFFICE OF
SOLID WASTE AND EMERGENCY RESPONSE
OSWER Directive 9200.4-26
MEMORANDUM
SUBJECT: Approach for Addressing Dioxin in Soil at CERCLA and
RCRA Sites
FROM: Timothy Fields, Jr. Acting Administrator
Office of Solid Waste and Emergency Respo
TO: Director, Office of Site Remediation and Restoration
Region I
Director, Emergency and Remedial Response Division
Region II
Director, Division of Environmental Planning and •>>
Protection
Region II
Director, Hazardous Waste.Management Division
Regions IX
Director, Waste Management Division
Region IV
Director, Waste, Pesticides, & Toxics Division
Region V
Director, RCRA Multimedia Planning & Permitting
Division
Region V
Director, Superfund Division
Regions III, V, VI, VII
Assistant Regional.Administrator, Office of Ecosystems
Protection and Remediation
Region VIII
Director, Hazardous Waste Program
Region VIII
Director, Office of Environmental Cleanup
Region X
Director, Office of Waste and Chemical Management
Region X
Printed on Recycled Paper
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PURPOSE
The purpose of this Directive is to recommend preliminary
remediation goals (PRGs) or starting points for setting cleanup
levels for dioxin in soil at Comprehensive Environmental
Response, Compensation and Liability Act (CERCLA) and Resource
Conservation and Recovery Act (RCRA) corrective action sites.
These recommended levels are to be used pending the release of
the U.S. Environmental Protection Agency (EPA) comprehensive
dioxin reassessment report and cross-program assessment of the
impacts of the report. One ppb (TEQs, or toxicity equivalents)
is to be generally used as a starting point for setting cleanup
levels for CERCLA removal sites and as a PRG for remedial sites
for dioxin in surface soil involving a residential exposure
scenario. For commercial/industrial exposure scenarios, a soil
level within the range of 5 ppb to 20 ppb (TEQs) should generally
be used as a starting point for setting cleanup levels at CERCLA
removal sites and as a PRG for remedial sites for dioxin in
surface soil. These levels are recommended unless extenuating
site-specific circumstances warrant a different level.
The dioxin levels discussed in this Directive are also
generally recommended for actions taken under RCRA at corrective
action sites. The recommended levels of 1 ppb (TEQs) for
residential soils and within the range of 5 ppb to 20 ppb (TEQs)
for commercial/industrial soils should generally be used as
starting points in setting soil cleanup levels at RCRA corrective
action sites. These levels are generally consistent with soil
cleanup levels set at RCRA facilities throughout the country
where dioxin is a principal contaminant of concern at the
facility. However, because states are the primary implementors
of the RCRA Corrective Action program, this Directive does hot
prescribe specific procedures for implementation under RCRA.
This Directive sets forth the policy basis for these
recommended levels and prescribes procedures for implementing
these recommendations.
BACKGROUND
To date, EPA has generally selected 1 ppb as a cleanup level
for dioxin in residential soils at Superfund and RCRA cleanup
sites where dioxin is a principal contaminant of concern at the
facility. EPA has also, to date, generally selected a cleanup
level for dioxin within the range of 5 ppb to 20 ppb for
commercial/industrial soils at Superfund and RCRA cleanup sites
where dioxin is a principal contaminant of concern at the
facility. The levels that EPA has selected at these sites are
protective of human health and the environment. Based on
presently available information, and using standard default
assumptions for reasonable maximum exposure scenarios, the upper-
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bound lifetime excess cancer risk from residential exposure to a
concentration of 1 ppb dioxin is approximately 2.5 x 10"", which
is at the higher end of the range of excess cancer risks that are
generally acceptable at Superfund sites. The calculated upper-
bound excess cancer risk associated with a lifetime
commercial/industrial exposure to 5 ppb, or the lower end of the
range recommended for commerciajL/industrial soils, is
approximately 1.3 x 10"!, which is also within the CERCLA risk
range. It should be noted that there is more difficulty in
generalizing about the cancer risk associated with
commercial/industrial cleanup levels than there is with
residential cleanup levels due to the greater variability in
exposures associated with commercial/industrial scenarios.
Accordingly, the consultation process for Superfund sites
referenced in the implementation section of this Directive should
be used to ensure the selection of appropriate, protective dioxin
levels at CERCLA commercial/industrial sites. Similarly, for
RCRA corrective action sites, please refer to the implementation
section of this Directive.
EPA is presently completing work on a comprehensive
reassessment of the toxicity of dioxin, to be embodied in the
documents entitled "Health Assessment Document for 2,3,7,8
tetrachlorodibenzo-p-dioxin (TCDD) and Related Compounds" and
"Estimating Exposure to Dioxin-like Compounds." The reassessment
report, which is scheduled to be issued in 1998, will represent
the culmination pf an Agency-wide effort to collect, analyze and
synthesize all of the available information about dioxin. It has
undergone significant internal and external review and is one of
the most comprehensive evaluations of toxicity of a chemical ever
performed by the Agency. Following release of the report, the
Office of Solid Waste and Emergency Response (OSWER) will
participate in a cross-program review of the implications of the
report for the regulation and management of dioxin by EPA. We
anticipate that this review will culminate in OSWER guidance
addressing the management of dioxin at CERCLA and RCRA sites.
The Office of Solid Waste and Emergency Response does not
believe it is prudent to establish new, and possibly varying,
precedents for Superfund or RCRA dioxin levels just prior to the
release of this reassessment report. As with any other
pollutant, it is important that EPA ensure appropriate national
consistency in remediation efforts. The Agency has used 1 ppb as
a residential cleanup level and between 5 ppb and 20 ppb as a
commercial/industrial cleanup level at CERCLA and RCRA cleanup
sites for dioxin in soil in the past; it is anticipated that
OSWER will be issuing guidance, informed by the reassessment
effort, that will provide a basis for the selection of dioxin
cleanup levels in the near future. In the interim, for sites
that require the establishment of a final dioxin soil cleanup
level prior to the release of the reassessment report and
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development of OSWER guidance, EPA should generally use 1 ppb
(TEQs) as a starting point for residential soil cleanup levels
for CERCLA non-time critical removal sites (time permitting, for
emergency and time critical sites) and as a PRG for remedial
sites. EPA should generally use a level within the range of
5 ppb to 20 ppb (TEQs) as a starting point for cleanup levels at
CERCLA non-time critical removal sites (time permitting, for
emergency and time critical sites) and as a PRG for remedial
sites for commercial/industrial soil. These levels should also
be used as starting points in setting soil cleanup levels at RCRA
corrective action sites.
For CERCLA remedial sites, consistent with 40 CFR
§ 300.430(f) (5) (iii) (D), EPA should commit to reviewing Records
of Decision (RODs) (i.e., RODs in which this Directive has been
used to develop dioxin soil cleanup levels) promptly following
the release and analysis of the reassessment report and OSWER
guidance, and, if necessary, to making changes to the RODs and
cleanup actions, based on the information contained in the
reassessment report and in the OSWER guidance. Similarly, in the
case of non-time critical removal actions (time permitting, for
emergency and time critical actions), EPA should commit to
reviewing Action Memoranda promptly following the release and
analysis of the reassessment report and OSWER guidance, and, if
necessary, to making changes to the-Action Memoranda and cleanup
actions, based on the information contained in the reassessment
report and the.OSWER guidance. EPA should similarly commit to
reviewing RCRA cleanup decisions (i.e., decisions for which this
Directive has been used) promptly following the release and
analysis of the reassessment report and OSWER guidance.
IMPLEMENTATION
Regional management should consult with the appropriate
Office of Emergency and Remedial Response (OERR) Regional Centers
on all proposed Fund and Potentially Responsible Party-lead site
decisions under CERCLA, including other Federal agency-lead and
state-lead site decisions, involving the development of dioxin
soil cleanup levels for non-time critical removal sites (time
permitting, for emergency and time critical removal sites) and
remedial sites. Consultation should be initiated at the risk
assessment stage. For Federal agency-lead sites, OERR will, in
turn, .notify the Federal Facilities Restoration Reuse Office of
ongoing consultations. The Office of Site Remediation
Enforcement will provide support if enforcement issues are
identified. For consultation procedures, refer to the OSWER
"Headquarters Consultation for Dioxin Sites", 9200.4-19,
December 13, 1996, plus the OSWER "Consolidated Guide to
Consultation Procedures for Superfund Response Decisions",
9200.1-18FS, May 1997.
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In the case of EPA-lead RCRA corrective action sites,
Regions should provide the Office of Solid Waste Permits and
State Programs Division (OSW/PSPD) with proposed dioxin soil
cleanup levels (i.e., prior to notice and comment) in order to
ensure appropriate implementation of this Directive. For
state-lead RCRA corrective action sites, it is also recommended
that states use the dioxin levels recommended by this Directive
as starting points in setting soil cleanup levels. States are
encouraged to share their approaches with the Regions in a manner
consistent with established procedures for EPA support and
oversight of state RCRA Corrective Action programs.
The levels in this Directive are recommended unless
extenuating site-specific circumstances warrant different levels,
a more stringent state applicable or relevant and appropriate
requirement (ARAR) establishes a cleanup level at CEP^LA sites,
or a more stringent state requirement applies at RCRA sites. We
recommend that levels other than 1 ppb (TEQs) for residential
soils and outside the range of 5 ppb to 20 ppb (TEQs) for
commercial/industrial soils be used only where evidence exists
that risks posed by the site differ from risks estimated using
standard national default guidance values. These recommendations
apply to RCRA corrective actions, CERCLA non-time critical
removal actions (time permitting, for emergency and time-critical
actions) and CERCLA remedial actions where cleanup levels are to
be developed for dioxin in soil, regardless of whether dioxin
itself drives the decision-making process.
The recommended levels found in this Directive, generally
considered protective of human health and the environment, apply
to surface soils. Please note that with respect to human health,
these levels are based on the direct contact exposure pathway.
The recommended levels in this Directive do not apply to other
exposure pathways, such as migration of soil contaminants to
ground water or to agricultural products. While the focus of
this Directive is on soils, these recommended levels also apply
to sediments in the event that this environmental medium is
considered to be a direct exposure pathway for human receptors.
This document provides guidance to EPA staff. The guidance
is designed to communicate national policy on dioxin cleanups for
soil. The document does not, however, substitute for EPA's
statutes or regulations, nor is it a regulation itself. Thus, it
cannot impose legally-binding requirements on EPA, states, or the
regulated community, and may not apply to a particular situation
based upon the circumstances. EPA may change this guidance in
the future, as appropriate.
If you have any questions1 concerning this Directive, please
contact either Marlene Berg at (703)603-8701 in Headquarters or
Elmer Akin of Region 4 at (404)562-8634, as Marlene and Elmer are
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co-chairs of the Superfund Dioxin Workgroup. For the RCRA
Corrective Action program, please contact Robert Hall of the
Office of Solid Waste Permits and State Programs Division at
(703)308-8484. Attached, for your information, is a list of
Regional points of contact who are serving on the dioxin
workgroup.
\ ,
Attachment: Superfund Dioxin Workgroup: Regional Points of
Contact
cc: Mike Shapiro, OSWER '
Peter Grevatt, OSWER
Steve Luftig, OERR
Elaine Davies, OERR
Larry Reed, OERR
Gershon Bergeisen, OERR
David Bennett, OERR
Bruce Means, OERR
Betsy Shaw, OERR
Paul Nadeau, OERR
Tom Sheckells, OERR.
Murray Newton, OERR
John Cunningham, OERR
Dave Evans, OERR
Joe LaFornara, OERR
Mark Mjoness, OERR
Jim Woolford, FFRRO
Elizabeth Cotsworth, OSW
Barry Breen, OSRE
Tudor Davies, OW
Craig Hooks, FFEO
Earl Salo, OGC
Bill Sanders, OPPT
Bill Farland, ORD
Regional Counsel, Regions I-X
Peggy Schwebke, Region 5
Superfund Dioxin Workgroup
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SDPERFUMD DIOXIN WORKGROUP - REGIONAL POINTS OF CONTACT
Region 1: Superfund/RCRA - Anne-Marie Burke. (617)223-5528
Region 2: Superfund - Marian Olsen. (212) 637-4313
RCRA - Richard Krauser. (212) 637-4166
Region 3: Superfund - Nancy Rios Jafolla. (215)566-3324
RCRA - Elizabeth Quinn. (215)566-3388
Region 4: Superfund - Elmer Akin. (404)562-8634
RCRA ^ Wesley S. Hardegree. (404)562-8486
Region 5: Superfund - Carol Braverman. (312)Br86-2610
RCRA - Mario Mangino. (312)886-2589
Region 6: Superfund - Ghassan Khoury. (214)665-8515
RCRA - Jeff Yurk. (214)665-8309
Region 7: Superfund - Bob Feild. (913) 551-7697
RCRA - Scott Ritchey. (913)551-7641
Region 8: Superfund contact Susan Griffin. (303)312-6651
RCRA - Tala Henry. (303)312-6648
Region 9: Superfund - Sophia Serda. (415) 744-2307
RCRA - Mary Blevins. (415)744-2069
Region 10:Superfund/RCRA - Marcia Bailey. (206) 553-0684
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