OSWER Policy Directive 9476.00-8.C
October 12, 1987
Prepared by:
P.O. Box 4400
Reston, VA 22090
Submitted to:
Office of Solid Waste
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
Contract No. 68-01-7090

This Technical Guidance Document presents the elements that
should be addressed in the development, implementation, and
certification of a clean closure plan for a hazardous waste
surface impoundment. These elements are waste and site
characterization, establishment of contamination cleanup
targets, delineation of waste removal and disposal procedures,
and sampling to confirm that targets have been met.
Marcia E. Williams
Director, Office of Solid Waste

Section	Page
Preface	vii
Executive Summary	ix
1	Introduction	1-1
1.1	Purpose, Content, and Organization	1-1
1.2	Background	1-2
1.3	Selecting a Closure Option	1-5
1.4	Clean Closure Requirements	1-9
1.5	References	1-13
2	Surface Impoundment Waste and Site	2-1
2.1	Facility Description	2-1
2.2	Waste Characterization	2-2
2.2.1 Waste Sampling and Analysis Plan	2-2
2.3	Ground-Water Evaluation	2-5
2.4	Surface Water Evaluation	2-6
2.5	Soil Evaluation	2-7
2.6	Quality Assurance/Quality Control
Requirements	2-8
2.6.1	General	2-8
2.6.2	Data Quality Objectives	2-9	DQO Stages	2-10	DQO Documentation	2-12
2.7	Chain of Custody	2-1!
2.8	References	2-1
3	Contamination Cleanup Targets
3.1	Introduction
3.2	Identification of Contaminants
of Concern
3.2.1	Waste Analysis
3.2.2	Environmental Media Sampling
and Analysis	3-5
3.3	Preliminary Cleanup Targets	3-6
3.4	Final Cleanup Targets	3-19
3.4.1	Chemical Mixtures	3-19
3.4.2	Detection Limits	3-20
3.4.3	Environmental Impacts	3-21
3.4.4	Site-Specific Exposure Pathways	3-21
3.4.5	Elevated Background Levels	3-21

Section	Page
3.5	Establishment of Background Levels	3-22
3.5.1	Ground Water	3-22
3.5.2	Soil	3-23
3.5.3	Surface Water	3-24
3.5.4	Air	3-24
3.6	Establishing Targets in the Absence of
Standards, Criteria, and Guidance	3-25
3.7	Incorporation of Final Cleanup Targets
into Facility Closure Plan	3-25
3.8	References	3-27
4 Waste Removal and Disposal	4-1
4.1	Introduction	4-1
4.2	Site Safety Plan	4-3
4.2.1	General	4-3
4.2.2	Information and Evaluation Factors	4-3
4.3	Liquid Removal	4-4
4.3.1	General	4-4
4.3.2	Information and Evaluation Factors	4-5
4.4	Sediment/Sludge Excavation and Removal	4-5
4.4.1	General	4-5
4.4.2	Information and Evaluation Factors	4-6
4.5	Liner Removal	4-7
4.5.1	General	4-7
4.5.2	Information and Evaluation Factors	4-7
4.6	Contaminated Soil Excavation and Removal	4-8
4.6.1	General	4-8
4.6.2	Information and Evaluation Factors	4-9
4.7	Soil Testing During Closure	4-9
4.7.1	General	4-9
4.7.2	Available Methods	4-10
4.7.3 Information and Evaluation Factors
4.8	Equipment Decontamination
4.6.1	General
4.8.2	Information and Evaluation Factors
4.9	Air Emissions Controls
4.9.1	General
4.9.2	Information and Evaluation Factors
4.10	Air Testing During Closure
4.10.1	General
4.10.2	Available Methods
4.10.3	Information and Evaluation Factors
4.11	References

Confirmation Monitoring and Sampling Programs	5-1
5.1	Introduction	5-1
5.2	Ground Water	5-1
5.3	Soils	5-2
5.4	Surface Water	5-3
5.5	Evaluation of Equipment Decontamination	5-4
5.6	References	5-5
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Excerpt from the Preamble to the	A-l
Final Rule on Modifications to the
Interim Status Regulations for the
Closure of Hazardous Waste Surface
Impoundments (40 CFR 265.228) dated
March 19, 1987 (Clean Closure
Two-Dimensional Random Sampling	B-l
Existing Standards, Criteria, and	C-l
EPA's Guidelines for the Health Risk	D-l
Assessment of Chemical Mixtures and
Guidelines for Carcinogen Risk Assessment
(Federal Register, September 24, 1986)
Onsite Treatment and Offsite Shipment	E-l
Information Requirements and Evaluation
Synthetic Precipitation Leach Test for Soils	F-l

Table No.	Page
1-1 Clean Closure Feasibility Checklist	1-4
1-2 Sample Outline Summary of Clean Closure
Plan	1-6
1-3 Checklist for Clean Closure Submittal	1-7
1-4 Comparison of Requirements Under	1-8
Clean and Landfill Closure Options
for Surface Impoundments
1-5 Sampling and Analysis Matrix for
Clean Closure of Surface Impoundments	1-10
3-1 Standard Intake Assumptions for Use
in Setting Preliminary Target Levels	3-8
3-2 Maximum Contaminant Levels (MCLs)
Promulgated Under the Safe Drinking
Water Act	3-9
3-3 Agency-Established Exposure
Limit Criteria and Preliminary
Cleanup Targets for Systemic Toxicants 3-10
3-4 Agency-Established Exposure Limit
Criteria and Preliminary Cleanup
Targets for Carcinogens	3-13
3-5	EPA Ambient Water Quality Criteria
(WQC) for Protection of Human Health	3-15
Figure No.	Page
1-1	Clean Closure Demonstration	1-3
2-1	DQO Three-Stage Process	2-11
3-1	Establishing Cleanup Targets	3-2
4-1	Key Steps in Surface Impoundment	4-2
Clean Closure

Subtitle C of the Resource Conservation and Recovery Act
(RCRA) required the U.S. Environmental Protection Agency
(EPA) to establish a Federal hazardous waste management pro-
gram. This program must ensure that hazardous wastes are
handled safely from generation until final disposition. EPA
issued a series of hazardous waste regulations under Sub-
title C of RCRA that are published in Title 40 Code of Fed-
eral Regulations (CFR) Parts 260 through 265 and Parts 122
through 124.
Parts 264 and 265 of 40 CFR contain standards applicable to
owners/operators of all facilities that treat, store, or
dispose of hazardous wastes. Wastes are identified or
listed as hazardous under 40 CFR Part 261. Part 264 stan-
dards are implemented through permits issued by authorized
States or EPA according to 40 CFR Part 270 and Part 271
regulations. Land treatment, storage, and disposal (LTSD)
regulations in 40 CFR Part 264 issued on July 26, 1962, and
July 15, 1985, establish performance standards for hazardous
waste landfills, surface impoundments, land treatment units,
and waste piles. Part 265 standards impose minimum tech-
nology closure and post-closure care requirements on the
owners/operators of certain landfills, surface impoundments,
and waste piles.
EPA is developing three types of documents to assist
preparers and reviewers of permit applications and/or plans
for hazardous waste land disposal facilities. The types are
RCRA Technical Guidance Documents (TGDs), Permit Guidance
Manuals, and Technical Resource Documents (TRDs). Although
emphasis is given to hazardous waste facilities, the infor-
mation presented in these documents may be used for design-
ing, constructing, and operating nonhazardous waste LTSD
facilities as well.
The RCRA TGDs present Resign, construction, and operating
specifications or evaluation techniques that generally
comply with or demonstrate tompliance with the Design and
Operating Requirements and the Closure and Post-Closure
Requirements of Part 264 and 265. The Permit Guidance
Manuals are being developed to describe the permit appli-
cation information the Agency seeks and to provide guidance
to applicants and permit writers in addressing information
requirements. These manuals will include a discussion of
each step in the permitting process and a description of
each set of specifications that must be considered for
inclusion in the permit.
The TGDs and Permit Guidance Manuals present guidance, not
regulations. They do not supersede the regulations promul-

gated under RCRA and published in the CFR. Instead, they
provide recommendations, interpretations, suggestions, and
references to additional information that may be used to
help interpret the requirements of the regulations. The
recommendation of methods, procedures, techniques, or speci-
fications in these manuals and documents is not intended to
suggest that other alternatives might not satisfy regulatory
The TRDs present summaries of state-of-the-art technologies
and evaluation techniques determined by the Agency to con-
stitute good engineering designs, practices, and procedures.
The summaries support the RCRA TGDs and Permit Guidance
Manuals in certain areas by describing current technologies
and methods for designing hazardous waste facilities or for
evaluating the performance of a facility design. Whereas
the RCRA TGDs and Permit Guidance Manuals are directly
related to the regulations* the information in the TRDs
covers a broader perspective and should not be used to
interpret the requirements of the regulations.
This document has been developed by the Agency to assist
owners and operators of hazardous waste surface impoundments
to comply with the "clean closure" requirements of 40 CFR
Parts 264 and 265. These regulations require removal or
decontamination of all waste residues, contaminated contain-
ment systems, and contaminated subsoils. The information
contained in this document provides a detailed description
of the policy regarding "clean closure" requirements that
was introduced in the preamble to the regulations amending
40 CFR Part 265.228(a), published in the March 19, 1987
Federal Register (Volume 52, No. 53).

This manual provides guidance to owners and operators seeking
to implement the "clean closure" of a hazardous waste surface
impoundment* The manual serves as a companion document to
another Agency publication: RCRA Guidance Manual for
Subpart G Closure and Post-Closure Care Standards and
Subpart H Cost Estimating Requirements, OSWER Policy
Directive 9476.00-5, January 1987. The primary focus of the
latter manual is in the area of general closure requirements
applicable to all hazardous waste facilities, such as proce-
dural and administrative requirements, closure cost estima-
tion methodology, post-closure care, and closure plan
This manual specifically addresses the technical
implementation and documentation requirements attendant to a
clean closure demonstration. The objective is to provide
necessary amplification of certain sections of the draft
Subpart G manual, and not to reiterate areas adequately
covered. In addition, detailed discussion of closure tech-
nologies such as removals, decontamination, or sampling and
analysis technique is not included; rather, the reader is
referred to the appropriate Agency guidance throughout the
A logical methodology is presented that can be used by the
applicant to determine what cleanup levels must be achieved
and what level of documentation of the clean closure process
will be required. Methodology to assess the adequacy of the
existing site data base and to collect additional data, as
necessary, is presented in Section 2. Section 3 provides
guidance and reference material that can be used to establish
contaminant cleanup targets. Section 4 discusses documenta-
tion of the proposed waste removal processes, and Section 5
discusses monitoring necessary to assure that cleanup
targets have been achieved.
Owners or operators planning to institute the clean closure
of a surface impoundment are advised to review the content
of the entire manual to first gain a realistic assessment of
the probability that a. clean closure can be achieved at
their particular sites. It is hoped that this document pro-
vides the necessary clarification of the difficult technical
issues associated with the demonstration of a clean closure
for hazardous waste surface impoundments.

Section 1
This guidance document specifically addresses the
requirements that must be met to implement the clean closure
of a hazardous waste surface impoundment in compliance with
the provisions of 40 CFR Parts 264.228 and 265.228. It pre-
sents both a detailed discussion of the elements of a clean
closure demonstration as well as the data requirements and
documentation that must be developed for incorporation into
the 6ite closure plan.
This manual supplements and is intended to be used with the
draft document RCRA Guidance Manual for Subpart G Closure
and Post-Closure Care Standards and Subpart H Cost
Estimating Requirements (Subpart G Guidance) (U.S. EPA,
1987), which addresses closure requirements applicable to
all hazardous waste treatment, storage, or disposal facil-
ities (TSDF). Together these two documents provide guidance
on data requirements and documentation that must be submit-
ted by an owner/operator planning to implement the clean
closure of a surface impoundment.
This guidance is not intended as a technical resource for
the scientific and engineering related elements of physical
closure procedures (i.e., waste removal, sampling proce-
dures, etc.); these aspects are covered in several other
Agency publications that will be referenced throughout this
document. The Technical Resource Documents titled Closure
of Hazardous Waste Surface Impoundments (U.S. EPA, 1982) ,
Hazardous Waste Surface Impoundments (U.S. EPA, 1986a), and
Guidance Document for Cleanup of Surface Impoundment Sites
(U.S. EPA, 1986b) should be consulted in conjunction vith
this document for guidance on closure technologies.
The methodologies and procedures presented in this manual
are based on a compilation of experience gained in the clo-
sure of many surface impoundments under the RCRA program.
They represent an acceptable means of satisfying clean clo-
sure requirements and an attempt to better define some of
these elements. However, this manual embodies no regulatory
authority; the owner or operator may of necessity use dif-
ferent procedures that are more technically suitable to clo-
sure of the individual surface impoundment, as long as the
performance standard for clean closure is met.
In addition to the delineation of clean closure
requirements, guidance on preparation of a clean closure
demonstration under these requirements will be presented.
The guidance presents the four primary components of a clean

closure demonstration in the order in which they would be
o Section 2 - Surface Impoundment Waste and Site
Characterization—Presents background data that
must be developed and submitted.
o Section 3 - Contamination Cleanup Targets-
Identifies the contaminants of concern and the
levels to which they must be removed.
o Section 4 - Waste Removal and Disposal—Describes
items that must be considered and documented for
the physical waste removal process.
-o Section 5 - Confirmation Monitoring and Sampling
Program—Describes sampling and analysis at the
conclusion of closure activities to ensure that
cleanup targets have been met.
A flow diagram of the clean closure demonstration process is
presented in Figure 1-1, indicating decision points and the
incorporation of the above elements into closure plan prepa-
ration. Prior to initiating the planning and engineering
analyses that are necessary to clean close a surface
impoundment, the owner or operator must first assess if
clean closure will be possible based on the characteristics
of the facility. The remainder of this section presents the
regulatory background and factors that must be considered in
making this decision.
All surface impoundments that have been used to manage
hazardous wastes, as defined in 40 CFR 261, must be closed
in compliance with the requirements of 40 CFR 264 or 265
(for interim status facilities) upon the cessation of opera-
tions. A surface impoundment is defined in 40 CFR 260.10 as
"a facility or part of a facility which is a natural topo-
graphic depression, man-made excavation, or diked area
formed primarily of earthen materials (although it may be
lined with man-made materials), which is designed to hold an
accumulation of liquid wastes or wastes containing free liq-
uids, and which is not an injection well." The owner or
operator of the impoundment must have a written closure plan
that is in compliance with all requirements of 40 CFR 264
Subpart G and 40 CFR 264.228 (40 CFR 265 Subpart G and
40 CFR 265.228 for interim 6tatus facilities).
The draft Subpart G Guidance (U.S. EPA, 1987) presents a
thorough discussion of the procedural and administrative

mplemekt son. sampling
Figure VI

Table 1-1
If answers to any of the following questions are "yes," it
is recommended that the owner/operator perform a feasibility
study before developing a closure demonstration plan or
beginning closure activities pursuant to achieving clean
1.	Do ground-water samples indicate contamination?
2.	Has extensive soil contamination beyond the unit
boundary been determined?
3.	Are soil or ground-water contaminant levels high,
relative to natural background levels?
4.	Have preliminary estimates of the volume of waste and
soil removal been made?
5.	Have preliminary estimates of the cost of treatment or
subsequent disposal of removed materials been made?
6.	Are many Appendix VIII hazardous constituents (more
than 10) found in the wastes at the unit? Are many
types of hazardous constituents (e.g.! volatiles,
metals, pesticides, etc.) present at the unit?
7.	Are any of the Appendix VIII constituents classified by
EPA as Class A or B carcinogens?
8.	Is excavation and subsequent management of the waste
likely to be dangerous to onsite employees or offsite
individuals because of release of volatiles to the

requirements that apply to plan submittal in Chapter 3,
guidance on preparation of a closure cost estimate in Chap-
ter 4, and an example of recommended closure plan content
and format in Appendix C.3. Administrative considerations
reviewed in that manual include Agency review procedures,
public involvement requirements, plan amendment procedures,
closure scheduling, closure notification, and closure certi-
-fication. The recommended outline for a clean closure plan
submittal is summarized in Table 1-2 on the following page.
The figure summarizes a detailed checklist of overall clo-
sure plan information submittal requirements presented in
Section A.3.1.8 of the Subpart G Guidance. This guidance
provides expanded information and a more detailed method-
ology .description for certain elements of the recommended
outline, primarily in the area of facility decontamination.
Table 1-3 presents a checklist of information submittal
requirements addressed in this manual for permitted facil-
ities. This checklist represents a guide to the submittal
of supplemental information immediately prior to the actual
date of closure implementation.
The owner or operator has two distinct closure options for a
surface impoundment: clean closure, or closure as a land-
fill. A summary of the key requirements under each of these
options is presented in Table 1-4. For clean closure, all
waste residues, contaminated containment system components
(liners, etc.), contaminated subsoils, and structures and
equipment contaminated with waste and leachate must be
removed from the site. If wastes or contaminated materials
are to be left on the site after closure, the facility must
be closed as a landfill. Landfill closure requirements,
specified under 40 CFR 264.310 and 40 CFR 265.310 (interim
status facilities), include the installation of a low perme-
ability cover, post-closure inspection, maintenance, and
monitoring, and, where appropriate, corrective action.
Landfill closure will not be addressed in this guidance doc-
ument. The reader is referred to the Permit Applicant's
Guidance Manual for Hazardous Waste Land Treatment, Storage,
and Disposal Facilities (U.S. EPA, 1984) for a.description
of landfill closure requirements and references to applica-
ble technical documents. It should be noted that 40 CFR
264.228 requires that an owner or operator submitting a
clean closure plan for a surface impoundment with no liner,
or a deteriorated liner, must also prepare contingency land-
fill closure and post-closure plans that would be imple-
mented in the event clean closure could not be achieved.
The owner or operator considering the implementation of
clean closure at a surface impoundment should first assess
the probability that such a closure can be successfully

Table 1-2
1.	FACILITY CONDITIONS: Includes facility description,
surface impoundment description, maximum extent of
operation, environmental permits, and list of
year; frequency of partial closure; time required for
waste treatment, removal, decontamination, final
closure; and support for deadline extensions
3.	REMOVAL OF ALL WASTE INVENTORY: Includes maximum waste
volume, handling and treatment/disposal of waste
liquids and sludges, and disposition of all removed
wastes and soils
4.	FACILITY DECONTAMINATION: Presents containment
systems, equipment and structures, contaminated soil,
and site reclamation and future use or disposition of
5.	GROUND-WATER MONITORING: Includes analyses required
during closure; maintenance of equipment; results of
monitoring during operating period; extent of contami-
nation, if any; and measures for corrective action
7.	CLOSURE CERTIFICATION: Lists the activities to be
conducted by Independent Registered Professional
Engineer and the documentation requirements
8.	CLOSURE COST ESTIMATES: Includes all sampling and
monitoring, waste management, and contingency closure
setting preliminary target levels, discussing
contingency for revising preliminary targets, and
sampling and monitoring plans to confirm that targets
are met
SOURCE: RCRA Guidance Manual for Subpart G Closure and
Post-Closure Care Standards and Subpart H Cost Estimating
Requirements, OSWER Policy Directive 9476.00-5, U.S. EPA,
January 7, 1987, Section A.3.1.8.

Table 1-3
o Waste, site characteristics tan update of originally
submitted data for permitted facilities)
o	Waste sampling and analysis plan
o	Ground-water evaluation
o	Surface water evaluation (sampling plan, if necessary)
o	Soil evaluation (sampling plan, if necessary)
o	Preliminary corvtamisvaftt cleanup targets
o	Site safety plan
o	Wa&te, liner, and contaminated soil removal procedures
o	Equipment decontamination procedures
o	Air emission control and sampling plan (if necessary)
o	Performance monitoring program
o	Confirmation monitoring plan
o	Site monitoring program OA/QC procedures including DQO
documentation and proposed chain-of-custody

Table 1-4
Clean Closure
Complete removal
Waste Constituents
Land Use
Operation and
Removal to the point
that no current or
future threat to human
health or the
environment exists
Required to confirm
clean closure has been
achieved; no
None (may be
necessary for other
units at the
Landfill Closure
Liquid removal;
stabilization of
remaining residues
may be required
to support cap
Left in place
Required during
Full RCRA cap
Deed/plat notice
required to
activities to
those that will
not disturb
access control
may be required
Maintain cover,
containment for
As dictated by

The primary factor to consider is the volume and areal
extent of contaminated subsoil (unsaturated and saturated)
that is likely to have resulted from surface impoundment
operation. In general, if contaminated ground water has
been detected at the downgradient point of compliance that
is attributable to the surface impoundment, clean closure
will not be possible until ground water has been cleaned up.
In practical terns, cleanup of contaminated ground water may
take an extensive period of time (well beyond the 180 days
required under 40 CFR 265.113), thereby rendering clean clo-
sure infeasible. In the case of a permitted facility, the
owner/operator would be required to implement a corrective
action program that will require monitoring for a period of
years. By definition, closure as a storage impoundment
(clean closure) requires no post-closure maintenance or
monitoring (see Appendix A for a more complete discussion of
the differences between landfill closure and clean closure).
If a significant amount of contaminated subsoil is likely to
exist at the facility, it may be more feasible for the owner
to implement landfill closure and post-closure care, and to
perform corrective action, rather than attempt to excavate
and dispose of all contaminated soil. This case is likely
to occur in impoundments without low permeability lining
systems or with liners that have deteriorated. Other fac-
tors that should be considered include the physical and
chemical characteristics of the waste, the permeability of
underlying strata, depth to the ground-water table, the
length of time- the facility has been in use, and the mobil-
ity of the potential contaminants in the subsurface environ-
ment. These factors are identified during characterization
of the waste and site, and other sampling and monitoring
programs. Table 1-5 summarizes the sampling and analysis
steps necessary for the clean closure process.
As discussed in succeeding sections, clean closure requires
that contamination in the subsoil be removed to levels that
would not pose a health risk through any route of exposure,
to include a dermal contact or direct ingestion scenario.
In addition, soil samples must be tested by an appropriate
leaching procedure, with the extract meeting applicable
standards. If there has been a contaminant release from the
facility, cleanup to these levels could involve excavation
of a significant volume of material. An owner or operator
who does not evaluate these factors could expend a signifi-
cant amount of resources on subsoil excavation and then
could find that cleanup levels cannot be met, and that clean
closure is not a feasible option.
The preamble to the final conforming changes to 40 CFR
265.228 promulgated on March 19, 1987, presents a detailed

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discussion of clean .osure requirements and the rationale
employed to arrive at these criteria. In addition to better
defining clean closure requirements, the regulation essen-
tially provides equivalent and consistent performance stan-
dards for closures of permitted and interim status facil-
ities. The technical discussion from the preamble is pre-
sented in Appendix A to this document; the remainder of this
section presents a summary of those requirements.
As stated in 40 CFR 265.226, to obtain the clean closure of
a surface impoundment the owner or operator must:
"Remove or decontaminate all waste residues,
contaminated containment system components (liners,
etc.,) contaminated subsoils, and structures and equip-
ment contaminated with waste and leachate...."
The remove or decontaminate mandate also applies to any
ground water that has been contaminated as a result of
facility operations. The Agency gives the following guid-
ance in the preamble to the regulation concerning the level
of decontamination that must be effected:
"...contaminants left in the subsoils will not impact
any environmental media including ground water, surface
water, or the atmosphere in excess of Agency estab-
lished exposure levels, and that direct contact through
dermal exposure, inhalation, or ingestion will not
result irt a threat to human health or the environment."
The point of exposure at which the above conditions must be
met is directly at or within the unit boundary. Thus, soil
or ground water at the surface impoundment excavation
(laterally and beneath) must meet decontamination criteria
or else must be removed. Remaining soils or other materials
must meet ingestion and dermal contact criteria based on
total waste constituent levels. In-place waste and/or soil
stabilization techniques are not considered to be viable
options, because of the uncertainty regarding their long-
term effectiveness.
The clean closure demonstration allows no presumption of
attenuation of contaminants (such as adsorption, chemical
reduction, etc.); therefore, fate and transport modeling or
other predictive methodologies are not applicable. Upon the
successful completion of clean closure, no post-closure con-
trols (fencing, capping, deed restrictions, etc.), inspec-
tion, maintenance or monitoring is required; the land may be
developed or transferred with no restrictions because of
prior hazardous waste management activities.
One of the primary goals of this manual is to provide the
surface impoundment owner or operator with guidance on what

data must be developed and submitted to demonstrate that the
requirements discussed above have been met. The demonstra-
tion would be described in detail, along with general clo-
sure information (as outlined in the draft Subpart G
Guidance, Section A.3) to form the overall site closure
plan. This guidance is intended to clarify requirements and
to answer as many questions as possible concerning the clean
closure demonstration. Some of the questions that have been
anticipated and the sections of this document that provide
guidance on them are presented below:
o What concentration of a specific contaminant may
remain in the subsoil or ground water?--
Section 3.4
o What constituents must be sampled for before and
after waste removal?—Section 3.2
o What information must be submitted concerning the
proposed waste removal and decontamination
methodology?—Section 4.0
o What if no standards or criteria exist for the
hazardous constituents of concern in the surface
impoundment?--Sections 3.5 and 3.6
o Can stabilized or solidified wastes or liner
materials be left onsite under clean closure?—
Section 1.4 '
o How many samples must be taken and at what
locations to confirm that clean closure has been
achieved?—Section 5.0
After the closure plan is approved and closure activities
have begun, it may be necessary to modify the closure plan
to incorporate revised or additional sampling and analysis,
based on the results of ongoing closure activities.

U.S. EPA, 1982, Closure of Hazardous Waste Surface
Impoundments, SW-873.
U.S. EPA, 1984, Permit Applicant's Guidance Manual for
Hazardous Waste Land Treatment, Storage, and Disposal
Facilities, SW-84-004.
U.S. EPA, 1986a, Hazardous Waste Surface Impoundments,
HWERL, Cincinatti, Ohio, Contract No. 68-03-1816.
U.S. EPA, 1986b, Guidance Document for Cleanup of Surface
Impoundment Sites, OSWER Policy Directive No. 9380.0-6.
U.S. EPA, 1986c, Test Methods for Evaluating Solid Wastes,
SW-846. 3rd Ed.
U.S. EPA, 1987, RCRA Guidance Manual for Subpart G Closure
and Post-Closure Care Standards and Subpart H Cost
Estimating Requirements, OSWER Policy Directive No.

Section 2
It is recommended that a description of the waste and site
characteristics should be prepared and included in the
closure plan as a guide to help the owner or operator
determine if all aspects of clean closure have been fully
addressed. For facilities permitted under 40 CFR Part 264
and 270, much of this data will have been included in the
RCRA Part B Permit application. Interim status facilities
may be required to complete additional investigations with
the results included in the submitted closure plan. The
owner or operator should refer to the draft Subpart G
Guidance (U.S. EPA, 1967) to determine information required
for Agency approval of a closure plan.
For applicants submitting a closure plan as part of a Part B
application for a new facility, it is recognized that cer-
tain data discussed in this section would not be available,
such as monitoring data, corrective activities, site safety
personnel, etc. The plan should be updated to include the
recommended information as soon as this information is
available and prior to beginning facility closure
Sections 2.1 through 2.7 give an overview of the data
recommended to characterize the waste and site. These
sections include facility description; waste, ground water,
surface water, and soil characterization; quality assurance/
quality control (QA/QC) procedures; and chain-of-custody
requirements. For new facility applicants or for operating
permitted facilities, the owner or operator can refer to the
applicable Part B information.
A detailed description of the facility, which incorporates
the surface impoundment being proposed for clean closure,
should be completed as a part of the initial site character-
ization. This description should include the following:
o Facility location and size
o Description of surface impoundment unit to be
closed, to include size, volume, type of liner,
access, and other technical specifications
o List of types of wastes managed at the impoundment
during its operating life, to include chemical and
physical characteristics

o List of other hazardous waste management units at
the facility, their volumes and capacities, and
types of wastes handled
o List of onsite facility equipment and structures
possibly requiring decontamination
o Description of security systems
o Description of weather and climatic conditions
that might potentially affect closure operations
such as flooding or freezing conditions, etc.
o Description of waste management corrective
measures being taken at the facility
o Description of any previous releases from the
unit or any other releases at the facility,
including spills from loading, unloading, or
overtopping, etc., and description of any
corrective measures taken in response
For an initial characterization of the waste, a summary of
the data identifying contaminants and physical state of
waste present in the surface impoundment should be com-
pleted. This -summary should include an estimate of the
maximum volume of waste present onsite in liquid, sludge,
and bulk waste form.
The waste within the surface impoundment boundary should be
analyzed to determine what hazardous constituents are pre-
sent. In addition, the waste sampling and analysis program
should be completed to characterize the waste depth, compo-
sition and homogeneity. Also, sludges, waste residues, soil
liners, and any subsurfade materials should be analyzed to
identify hazardous constituents and to provide a basis for
estimating the extent of excavation that may be required.
Section 3.2.1 contains a discussion of the identification of
contaminants of concern, which is the goal of the waste
sampling and analysis plan.
The owner/operator is strongly encouraged to prepare a
complete waste sampling and analysis plan. The purpose of
this plan is to identify Appendix VIII and any additional
hazardous constituents (e.g., asbestos) considered to be
possibly present in the surface impoundment unit, which
could result in a public health threat. If certain haz-
ardous constituents present in the surface impoundment were

not associated with the process that produced the waste, the
possibility exists for excessive levels of such contaminants
remaining in the environment after closure. Therefore, to
avoid the possibility of incomplete closure, an evaluation
of all records of waste materials present in the surface
impoundment should be reviewed, in addition to a comprehen-
sive sampling and analysis program. These sampling and
analysis results should be used to develop the following:
o An evaluation of the feasibility of clean closure
o Cleanup targets
o_ Safety considerations to be implemented during
closure operations, which includes a determination
of potential air emission problems
o A plan to manage the w&ste and other materials
upon removal from the surface impoundment
o Documentaticr ft> - r^during analytical parameters
for environmental media analysis
The waste sampling and analysis plan should include waste
sampling strategies and procedures, waste analysis methods,
and appropriate QA/QC procedures.
Some specific parameters of the waste sampling and analysis
plan for clean closure of a surface impoundment are
presented below:
o Appropriate Sampling Location and Depths—-
Representative samples of the waste should be
collected at several depths within the surface
impoundment to characterize the waste. The areal
distribution of the sampling locations should be
determined using a two-dimensional, random-sampling
technique as specified in Appendix B. Adequate
samples should be collected to establish the waste
stratification within the surface impoundment,
based on viscosity and/or density analysis. The
plan should include the rationale used to
determine the sampling locations, depths, and
analysis parameters.
o Sufficient Number of Sampling Sites—Generally,
the greater the number of sampling sites used, the
more reliable the data will be. No standard
number can be prescribed for all facilities.
However, the number of sampling sites necessary
will be a function of the variability of waste
stream constituents received over time and the

area and depth of the surface impoundment. A
sufficient number of samples (in no case fewer
than four) from each depth (discussed in the
paragraph above) should be collected and analyzed.
The number of samples at each depth should be
determined by the random sampling approach applied
to the site to ensure representative sampling of
the waste that is in the impoundment at the time
of closure.
o Parameters To Be Measured—The objective of the
waste analysis is to identify contaminants of con-
cern including Appendix VIII parameters present at
the site. Rather than perform a full Appendix VIII
analysis on all samples, the owner/operator may
choose to first screen the sample to identify
classes of pollutants that may be present, using
standard SW-846 (U.S. EPA 1986a) test methods. If
classes of contaminants (metals, volatile and semi-
volatile organics, pesticides, PCBs, etc.) are not
found, the tests for individual Appendix VIII para-
meters within the class need not be conducted.
Any additional hazardous (non-Appendix VIII) con-
stituents that are determined to be possibly pre-
sent in the surface impoundment and that are a
threat to public health should be analyzed. The
owner/operator should analyze at least some of the
samples collected for general physical or chemical
parameters. A knowledge of these parameters can
help define the waste removal, treatment, and
disposal requirements. Although the lack of
appropriate analytical techniques may limit the
analysis, the owner/operator should make every
reasonable effort to identify any Appendix VIII
The waste residues that are removed from the
impoundment must be managed as a hazardous waste
(unless they are no longer hazardous wastes pur-
suant to 40 CFR Part 261.3(d)) and, therefore, may
be subject to prohibitions on any subsequent land
disposal, pursuant to 40 CFR Part 268. If the
waste is restricted from land disposal, it must be
treated by an appropriate method that meets the
treatment standards of 40 CFR Parts 268.40 to
268.44. The owner/operator should analyze the
waste for chemical and physical properties rela-
tive to the methods of treatment that may be used
for subsequent management of the removed waste.
o Types of Samples—Grab samples are preferable to
composite samples. This is particularly true for
the identification of volatile organic compounds.

However, the use of composite samples may prove
useful for other parameters, particularly at sites
where the chemical characteristics of the waste
vary considerably over time and a large number of
samples are required. A description of the types
of samples obtained and the rationale behind this
decision should be included in the waste
characterization discussion.
The purpose of evaluating the ground-water system is to
complete a preliminary assessment of ground-water quality
and to determine the presence and extent of ground-water
contamination. Monitoring results may be used to identify
constituents for setting cleanup targets, as discussed in
Section 3.2. Based on this information, the owner/operator
can more accurately determine if clean closure is a feasible
option for the surface impoundment in question. Clean
closure of a surface impoundment cannot be evaluated without
having in place an adequate ground-water monitoring system.
Where the owner/operator can demonstrate that no contamina-
tion has reached the water table, limited ground-water
monitoring (i.e., for confirmation purposes only) may be
required. Where ground-water contamination 
The purpose of the surface water evaluation is to determine
if the surface water or sediments have been contaminated by
the surface impoundment or if the surface water or sediments
will be threatened with potential contamination during clo-
sure activities. This evaluation should help determine if
cleanup targets must be set for the surface water and
An evaluation of potentially contaminated surface water
bodies located directly adjacent to or downgradient from the
surface impoundment should be completed. The evaluation
should also consider locations where the surface water body
may be hydraulically connected to ground water. If it is
shown that surface water or sediment could not be affected
by the impoundment because of factors such as distance or
topographic features, then sampling and analysis would not
be necessary.
During the site characterization, the potential for past and
future contaminant migration to surface water and sediments
should be addressed. Where records of previous releases
exist, they should be included. This evaluation is neces-
sary to determine if surface water or sediments have been
contaminated from runoff, flooding, or ground-water dis-
charge, or if they may be contaminated during closure. If
it has been determined that sampling is necessary, the
number of samples, locations, and frequency of sampling
should be included in the closure plan. The number of
samples necessary to adequately characterise the potential
contaminant will depend on the size of the surface water
body and flow rates. A minimum of four samples should be
collected and analyzed from each potential surface water
body and sediment source downstream from the surface
impoundment. These samples should be taken as close to the
boundary of the surface impoundment as possible, or at the
point of entry to the surface water body of any known prior
release. However, if it appears there is discharge from an
aquifer into the surface water, samples should be obtained
from the point where the ground water discharges into the
surface water. If less than four samples are taken from one
source, documentation and justification need to be included
in the submitted report.
It will be necessary to estimate the extent of any soil
contamination to determine the feasibility of clean closure.
If hazardous constituents have migrated into the soil column
or have spread from the unit into adjacent soils as a result

of spills, leaking, over-topping, or other releases, the
owner/operator may be required to perform extensive soil
excavation prior to completing closure. Hazardous constit-
uents that are migrating through the soil column may not
have caused ground-water contamination at the time of clo-
sure, when ground-water monitoring results are being
reviewed to determine the feasibility of clean closure.
However, before clean closure can be completed, soil
contamination profiles must be examined and any hazardous
constituents in concentrations that may eventually cause
ground-water target levels to be exceeded must be removed.
Operations records should be reviewed to determine the
potential nature and extent of soil contamination in areas
that are directly adjacent to the surface impoundment, which
might have been contaminated by spills, overflows during
flooding, or routine operations. This determination will
help the owner/operator decide if clean closure is feasible
by providing a basis for estimating the amount of 6urficial
soils that might need to be excavated.
The soil evaluation should include an estimate of the
quantity of contaminated soil and a description of the
criteria used to determine the amount of contaminated soil.
As presented in the Subpart G Guidance (U.S. EPA, 1987),
these criteria would include the following:
o Types of soil testing (soil core, composite, grab
samples, etc.)
o Number, location, and depth of soil samples before
and after waste removal
o Parameters for analyses (contaminants of concern
identified during waste characterization)
o Analytical techniques, including column studies or
leaching procedures
The soil underlying the surface impoundment will be
evaluated upon removal of the waste and liner. This soil
testing program is discussed in Section 4.7—Soil Testing
During Closure. A sufficient number of soil cores should be
taken to adequately characterize the extent of vertical
migration of hazardous constituents in the unsaturated
In addition to the preceding, the owner/operator should
evaluate the chemical and physical characteristics of the
contaminated soil with respect to its treatability. Any
soil that is removed from an impoundment unit during closure
will, in most case6, be a hazardous waste and will be sub-
ject to regulation under Subtitle C of RCRA. The contamina-

ted soil may be banned from land disposal pursuant to 40 CFR
Part 268 (Land Disposal Restriction, FR Vol. 51, No. 216,
November 7, 1986) and may have to meet the treatment stan-
dards of 40 CFR Parts 266.40 to 268.44. The owner/operator
must determine the type of treatment that is appropriate for
soils contaminated with hazardous constituents and that will
meet the 40 CFR Part 268 treatment standards.
If the owner/operator can demonstrate that the soil removed
during closure activities is no longer a hazardous waste,
pursuant to 40 CFR 261.3(d), there is no further requirement
to manage the soil as a RCRA Subtitle C waste. However, the
non-hazardous soil must be removed and managed in a manner
consistent with Federal, State, and local requirements for
municipal solid waste, or nonhazardous industrial waste.
The scientific and related analytical data developed for,
and implemented during, clean closure of a surface impound-
ment is to be of a quality that will support and withstand
any scientific and/or legal inquiries. Therefore, a quality
assurance/quality control (QA/QC) program should be imple-
mented for all installation, monitoring, sampling, and
analyses required prior to and during closure operations.
The objective of the QA/QC program is to ensure that there
is sufficient and adequate documentation to defend the
To assure that this objective is met, the QA/QC program
submitted as a section of the closure plan should, at a
minimum, include the following:
1.	Methods used to determine the number of samples and
location of sampling points in the waste, ground water,
surface water, soil, and air
2.	Depth of sample collection
3.	Type(si of sampling and removal equipment used
4.	Methods of decontamination of equipment (sampling and
removal equipment, etc.)
5.	Compositing procedures to be used
6.	Analytical methods to be used

7. A list uf all analytical parameters, preservation
methods, and handling and shipping procedures
(Replicate samples should be analyzed routinely to
monitor sampling procedures.)
The material in this section is abstracted from the OSWER
Directive 9355.0-7A, Data Quality Objectives Development
Guidance for Uncontrolled Hazardous Waste Site Remedial
Response Activities (U.S. EPA,. 19B6c). The reader should
refer to that manual for a more detailed discussion of the
Data quality objectives (DOOs) are qualitative and
quantitative statements that outline the decisionmaking
process and specify the data required to support Agency
decisions during closure activities, including site charac-
terization, confirmation monitoring. Individual site char-
acteristics make it impossible to apply a generic set of
DQOs to all RCRA activities; therefore, site-specific DQOs
must be developed based on the proposed end uses of the data
from sampling and analytical activities.
To ensure that the data generated during closure activities
are adequate to support decisions, a clear definition of the
decisions should be established early in the closure plan-
ning process. These determinations are facilitated through
the development of data quality objectives (DQOs).
It is important to realize that DQOs are an integrated set
of thought processes that define data quality requirements
based on the identified end use of the data base. The DQO
is not a separate deliverable. The rationale behind the
selection of a particular sampling and analysis option will
appear in meeting minutes or internal memos that will become
part of the closure plan, and in work plans for the sampling
and analysis. The result of the DQO process will be a well'
thought-out sampling and analysis plan that details the
chosen sampling and analysis options.
DQOs are established before data collection and are critical
in developing a sampling and analytical plan (S&A Plan)
consistent with RCRA program objectives. DQOs are developed
to address the specific requirements of individual sites and
are based on the intended uses of the data. Through imple-
mentation of the DQO process, it is possible to calculate
the level of uncertainty associated with the data collected
during closure activities. It is important to note that
this calculation can be done accurately with a large (i.e.,
approximately 20 data points) existing data base. With a
limited amount of data, the calculation of the level of
uncertainty can be done only at the conclusion of data

analysis. The level of uncertainty can then be used in
making decisions regarding site closure.
Data quality objectives should be specified for each data
collection activity associated with closure, including site
characterization, soil excavation, and confirmation moni-
toring. All investigation activities should be conducted
and documented so that sufficient data of known quality are
collected to make sound decisions concerning closure.
Data quality objectives are identified during the course of
site characterization planning and during development of
sampling and analysis plans. DQOs are established to ensure
that the data collected are sufficient and of adequate qual-
ity for their intended uses. Data collected and analyzed in
conformance with the DQO process can be used in assessing
the uncertainty associated with each closure activity. DQO Stages
Data quality objectives are developed through a three-step
process as illustrated in Figure 2-1. Although the three
stages are identified and discussed sequentially below, they
should be undertaken in an interactive and iterative manner
whereby all elements of the DQO process are continually
reviewed and applied during closure. As such, the DQO
process is applied and the resultant S&A plan is developed
for inclusion in the closure plan. The process is revised
or expanded as needed based upon the results of each data
collection activity. This process is illustrated in the
companion OSWER Directive, Data Quality Objective Develop-
ment Example for Uncontrolled Hazardous Waste Site Remedial
Response Activities (Example Scenario I—RI/FS Activities at
a Site with Contaminated Soils and Ground Water) (U.S. EPA,
1986d). It is anticipated that several DQO Example Manuals
addressing a range of different site conditions (landfills,
lagoons, etc.) will be developed in the future.
o STAGE 1—Identify Decision Types.
Stage 1 of the DQO process provides the foundation
for Stages 2 and 3. Stage 1 is undertaken to
define the types of decisions that will be made.
In Stage 1, all available information on the site
is compiled and analyzed to dievelop & conceptual
model understanding of the site. This model
describes suspected sources, contaminant pathways,
and potential receptors. The model facilitates
identification of decisions that must be made and
deficiencies in the existing information. Stage 1
activities include defining program objectives and
identifying and involving end-users of the data.

Figure 2-1
Sourc* US EPA 1966d

Stage 1 results in specifying the decisionmaking
process and in forming an understanding of why new
data are needed.
o STAGE 2—Identify Data Uses/Needs.
Stage 2 results in the stipulation of the criteria
for determining data adequacy. This stage
involves specifying the level of data uncertainty
sufficient to meet the objectives specified in
Stage 1. Stage 2 Includes selection of the sam-
pling approaches and the analytical options for
the site, including evaluation of multiple-option
approaches to effect more timely or cost-effective
data collection and evaluation.
o STAGE ^--Design Data Collection Program.
Stage 3 results in the specification of the
methods by which sufficient data of acceptable
quality and quantity will be obtained to make
decisions. The StA plan should provide this
information. DQO Documentation
The DQO development process is initiated during site
characterization planning and is completed in conjunction
with the development of a sampling and analysis (SiA) plan
for each project phase. The various stages of the DQO
development process are interactive in nature. As addi-
tional details regarding the site are discovered, the
decisions that will be made during closure are further
refined. This refinement of decisions allows for further
specification of data needs and for design of the data
collection program.
The owner/operator should include full documentation of
Stages 1, 2, and 3 in the closure plan. During closure plan
evaluation, the State or Regional EPA permit writer will
review and approve the DQO documentation. As closure
activities commence, the owner/operator and the permit
writer will determine more precisely the Stage 2 data uses
and needs and the Stage 3 data collection program.
It should be noted that as the DQO process continues, the
scoping of the project will become refined. It may be
determined that additional decision types are needed
(Stage 1) or that data collection activities previously
identified should be modified (Stage 2 and Stage 3) as a
result of evaluation of data (Stage 1) collected during
earlier phases of closure.

Development of DQOs in a formal manner ensures that the
appropriate data are obtained to meet the closure objec-
tives. Documentation of DQOs can be provided primarily in
the S&A plan with summary information listed in the work
Chain of custody establishes the documentation and control
required to identify and trace a sample from collection to
completion of analysis. The owner/operator should include a
section in the closure plan explaining how chain of custody
will be implemented and followed during all sampling and
analysis phases.
The chain-of-custody plan should include the following:
o Labeling samples
o Sealing containers to control tampering
o Securing custody
o Maintaining necessary records to support potential

U.S. EPA, 1986a, Test Methods for Evaluating Solid Wastes.
SW-84 6, 3rd Ed.
U.S. EPA, 1986b, RCRA Ground-Water Monitoring Technical
Enforcement Guidance Document, OSWER Policy Directive
No. 9950.1.
U.S. EPA, 1986c, Data Quality Objectives Development
Guidance for Uncontrolled Hazardous Waste Site Remedial
Response Activities (Draft), OSWER Directive 9355.0-7A.
U.S. EPA, 1986d, Data Quality Objectives Development Example
for Uncontrolled Hazardous Waste Site Remedial Response
Activities, (Example Scenario I--RI/FS Activities at a
Site with Contaminated Soils and Ground Water) (Draft),
OSWER Directive 9355.0-7A.
U.S. EPA, 1987, RCRA Guidance Manual for Subpart G
Closure and Post-Closure Care Standards and Subpart H
Cost Estimating Requirements (Draft), OSWER Policy
Directive No. 9476.00^5.

Section 3
This section presents a systematic approach that can be used
to identify contaminants of concern and cleanup targets, as
well as help the owner/operator understand the ultimate
cleanup goals that must be met to effect the clean closure
of a hazardous waste surface impoundment. To certify clean
closure of a hazardous waste surface impoundment unit, the
owner/operator must comply with the closure performance
standard specified in 40 CFR Part 264.111/265.111. The
closure performance standard referenced above states:
"The owner or operator must close his facility in a«
manner that:
(a)	Minimizes the need for further maintenance
(b)	Controls, minimizes, or eliminates, to the
extent necessary to protect human health and
the environment, post-closure escape of haz-
ardous wastes, hazardous waste constituents,
leachate, contaminated rainfall, or waste
decomposition products to the ground or sur-
face waters or to the atmosphere."
Compliance with this performance standard for clean closure
will require particular emphasis on the underlined require-
ments. In addition, contamination cleanup targets for clean
closure must be 6et in a manner that eliminates the need for
post-closure maintenance or monitoring. It is important to
stress that upon clean closure, no subsequent post-closure
monitoring will be required and the property owner will not
be subject to RCRA-imposed restrictions on the use of the
property. Additional discussion of clean closure require-
ments and goals is presented in Section 1.4.
The process of establishing appropriate contamination
cleanup targets requires (1) the identification of the con-
taminants of concern (Section 3.2) and (2) the identifica-
tion of residual contaminant concentration levels that the
owner/operator can demonstrate are protective of public
health and the environment (Sections 3.3, 3.4). Step (2)
above is generally accomplished through the identification
of preliminary cleanup targets which may be subsequently
modified to establish final cleanup targets as shown on
Figure 3-1.
Generally, the identification of the contaminants of concern
is accomplished by conducting a comprehensive sampling and
analysis program of the waste preser.t in the surface

Figure 3-1

impoundment (as discussed in Section 2.1), by examining
records of wastes managed at the impoundment, and by examin-
ing ground-water monitoring data. However, there may be
situations that warrant analysis for additional Appen-
dix VIII constituents. These situations will be discussed
in Section 3.2. In addition, the intensity of the waste
sampling and analysis program (number and location of sam-
ples required) may be affected by the consideration of cer-
tain factors. These factors are also discussed in
Section 3.2.
Preliminary cleanup targets (PCTs) should be set for all
contaminants of concern based on maximum concentration lev-
els (MCLs) or Agency-established health-based exposure lim-
its (Section 3.3) when MCLs do not exist. If these stan-
dards and criteria do not exist for certain contaminants of
concern, the PCT may be based on background concentration
(Section 3.5) or toxicity test data (Section 3.6).
Site-specific data is used to adjust PCTs (either up or
down) to establish final cleanup targets (FCTs) (Sec-
tion 3.4). Often, this data will not be available until
after the closure plan is submitted and approved, and after
the waste, liner, and possibly some soils have been removed.
PCTs may have to be lowered due to additive effects of chem-
ical mixtures, site-specific exposure scenarios, or poten-
tial environmental impacts. PCTs may be raised if it can be
demonstrated that no benefit would be gained from the
attainment of -the lower target levels. This could occur in
areas with high background concentrations, attributable to
naturally occurring sources, or other man-made sources
beyond the control of the owner or operator of the facility.
As presented in Figure 3-1, the establishment of cleanup
targets may involve an iterative process of waste removal
and disposal (Section 4), confirmation sampling (Section 5),
evaluation of the potential health risks posed by residual
contamination (Section 3.4 and Appendix D), and either
another round of contaminant removal followed by.confirma-
tion sampling and ri6k evaluation, or confirmation of clean
closure. This reevaluation process is important for the
owner or operator to assure that the preliminary target lev-
els are still realistic and that clean closure is still fea-
sible. If there is any doubt that final confirmation
monitoring will indicate that all final target levels can be
met, the owner/operator may want to evaluate other closure
The owner/operator of a hazardous waste surface impoundment
is responsible for identifying all of the hazardous constit-
uents that may have been generated, used, stored, disposed

of, or otherwise managed at the facility and may be present
in the impoundment or surrounding environmental media at the
time of closure. These constituents include, but are not
limited to, those listed in 40 CFR Part 261, Appendix VIII.
To accomplish this identification, the owner/operator may
analyze waste, soil, surface water, and ground water for all
such hazardous constituents. However, analysis of all these
constituents in each medium may not be necessary for all
samples if it can be demonstrated that only a limited number
of these constituents could be present at the surface
impoundment unit. The most convincing means of demonstrat-
ing the absence of Appendix VIZI contaminants in the
environment is by performing a thorough Appendix VIII waste
analysis and by examining the results of ground-water moni-
toring performed during the operating period.
The owner/operator should develop a comprehensive waste
sampling and analysis plan that is designed to determine,
authoritatively, the constituents of concern at the surface
impoundment unit. Waste sampling and analysis plans are
discussed in Section 2*2.1. In general, the owner/operator
has the option of developing and proposing the use of an
analysis plan or analyzing all waste samples collected under
the waste sampling and analysis plan for all Appendix VIII
hazardous constituents, other hazardous substances known to
be used, stored, or disposed of at the facility, and any
degradation products of the above.
As previously discussed, rather than perform a full
Appendix VIII analysis on all samples, the waste analysis
plan may include a preliminary screening step to identify
classes of pollutants that may be present, using standard
SK-846 (U.S. EPA, 1986a) test methods. If classes of con-
taminants (metals, volatile and semi-volatile organics, pes-
ticides, PCBs, etc.l are not found, the tests for individual
Appendix VIII parameters.within the class need not be con-
ducted. The owner/operator should propose a reporting plan
such as all Appendix VIII constituents identified during
analysis plus the 10 to 20 non-Appendix VIII constituents in
highest concentration. A variance ©ay be granted for con-
stituents for which analytical procedures have not been
approved by the Agency. Also, where reliable records exist
on the wastes managed at the impoundment throughout its his-
tory, and where a high degree of certainty has been achieved
in any ongoing waste sampling and analysis program, waste
analysis requirements could be reduced. The State or
Regional EPA permit writer will review the waste analysis
results and will determine the extent of further analysis of
waste samples. The elimination of any Appendix VIII con-
stituent from analysis in soil, ground water, surface water,
or other environmental samples will be considered if that

constituent is not identified as a constituent of concern
upon review of the results of the waste sampling and
analysis program, and if there is no likelihood that the
constituent could degrade to produce other Appendix VIII
The owner/operator way be required to analyze all soil,
ground-water, and surface water samples for all Appen-
dix VIII or Appendix IX constituents and any potential
degradation byproducts. However, if warranted and properly
documented, the owner/operator may reduce the number of
parameters analyzed in the remainder of the closure process.
The criteria for determining whether a hazardous constituent
listed in Appendix VIII or Appendix IX should be eliminated
as a contaminant of concern at a surface impoundment unit
will normally be based on the results of waste sampling and
analyses and on the records of waste management, where the
records are reliable. However, the owner/operator may wish
to provide a demonstration that analyses for certain con-
stituents are not necessary based on the waste analysis plan
results. Such demonstrations will be reviewed on a case-
by-case basis. The owner/operator must demonstrate either
that (1) certain constituents could not be present at the
facility or that (2) analyses of certain constituents would
not provide reliable analytical results regarding the
presence of those constituents, because of limits of
To demonstrate that certain constituents could not be
present at the facility, the owner/operator may wish to pro-
vide information that includes but is not necessarily
limited to:
o The raw materials, intermediate products,
byproducts, and final products used or produced at
the facilities contributing wastes to the surface
impoundment (e.g., manifests, chemical purchase
orders, record ledgers, etc.)
o The degradation products of the constituents known
to be present in the unit
o Available waste sampling and ar.alysis data
For relatively simple wastes, such information may support a
demonstration that environmental media analyses could be
reduced from the Appendix VIII or Appendix IX listing, yet
could still identify all of the constituents of concern at a
facility. However, in some cases, even well presented
demonstrations may still leave a reasonable doubt regarding
unidentified waste constituents during clean closure.

To v-emonstrate that analysis for certain constituents would
not provide reliable analytical results, the owner/operator
must identify the constituents for which no standard or
acceptable analytical methods have been developed.. Upon
Agency review of the list of such constituents, the require-
ment to analyze for these constituents may be waived, if
Preliminary cleanup targets for soils and ground water are
concentration-b#sed numbers derived from Agency-established
health-based exposure limit criteria. Preliminary cleanup
targets provide an initial estimate of clean closure
requirements for hazardous waste surface impoundments. In
addition, these targets provide a means for estimating clean
closure requirements in written closure plans that muet be
submitted before determining actual types and concentrations
of contaminants in the 6oils and ground water beneath the
surface impoundment. In addition, targets provide numbers
that an owner/operator can consider when evaluating the fea-
sibility of the clean closure option. For facilities with
sufficient monitoring data, preliminary cleanup targets may
help the owner/operator to develop an order-of-magnitude
cost estimate for contaminated soil removal. The use of
preliminary targets may also allow a more precise soil
removal cost estimate during closure with data generated
during soil testing (see Section 4.7).
To evaluate the carcinogenic and systemic health effect
risks posed by residual concentrations of constituents in
soil and ground water under a surface impoundment, health-
based targets for clean closure are derived from Agency-
established exposure limits. Agency-established exposure
limits include:
o Maximum Contaminant Levels (MCLs) developed by the
Office of Drinking Water
o Health-based limits on verified reference doses
(RfDs) developed by the E7A Risk Assessment Forum
(U.S. EPA, 1986a)
o Carcinogenic potency factors (CPF) developed by
EPA's Carcinogenic Assessment Group (U.S. EPA,
o National Ambient Air Quality Standards
RfDs are chemical exposure criteria for noncarcinogenic
effects of systemic toxicants. For substances not known to
display carcinogenic properties, the RfDs are daily intake
levels at which no adverse effects are likely to occur over

chronic exposure. CPFs are a measure of the probability of
a carcinogenic response per unit intake of a chemical over a
lifetime. The CPF is the slope of the dose-response curve
based on the linearized multistage model. These exposure
criteria are discussed in more detail in Appendix C.
The application of the Agency's risk assessment guidelines
and chemical exposure criteria to evaluate potential health
risks requires the establishment of intake rates. Standard
intake assumptions have been developed for the purposes of
this manual and are presented in Table 3-1. The intake
assumptions are based on reasonable worst case scenarios and
are applied consistently to all clean closure target levels
regardless of any unique site factors. This conservative
approach is considered necessary because there are no
restrictions on future site use once clean closure has been
completed. Therefore, there is no basis for assuming at any
site that the worst case scenario will not, in fact, occur.
It is important to note that the Agency has published Guide-
lines for Estimating Exposure (U.S. EPA, 1986c) that should
normally be used for assessing health risks from environ-
mental pollutants.
Preliminary cleanup target for each potential route of
exposure should be based on the most appropriate Agency-
established exposure limits and the exposure assumptions
listed in Table 3-1. The following levels should be used
for setting preliminary target levels in each medium:
1.	For all routes of exposure involving a drinking water
scenario, the target levels should be the Maximum Con-
taminant Levels (MCLs) established as drinking water
standards under the Safe Drinking Water Act. The
Agency is in the process of proposing and finalizing
additional MCLs, and will continue to do bo over the
next several years. (See Table 3-2.)
2.	Where no MCLs currently exist, however, the target
levels involving a drinking water scenario should be
based on the Reference Doses (RfDs) for threshold con-
taminants and on Carcinogenic Potency Factors (CPFs)
forgnonthreshold contaminants, assuming a_risk level of
10~ for Class A and B carcinogens and 10~ for Class C
carcinogens.* (See Tables 3-3 and 3-4.)
•The Superfund program sets cleanup targets for carcinogens
based on evaluation of various alternatives that will
achieve levels of protection within the range of 10~ to
10" . Although cost and technical practicability are
additional factors that would be considered at Superfund
sites that would not be considered in setting cleanup
targets for RCRA clean closures, most Superfund remedies
achieve a level of protection of 10~ to 10~ anyway.

Table 3-1
1	gram/dav for 17 kg child
Ground Water:
2	liters/day for 7 0 kg adult
Surface Water:
2 liters of water/day for 70 kg adult
6.5 gm of fresh water fish/day for 70 kg adult
20 air/day for 70 kg adult
10 air/day for 10 kg child
^Assumes normal hand-to-mouth behavior of an infant or
toddler (less than 6 years old).
NOTE: Exposure assumptions are subject to change, based
on the results of Agency review.

Table 3-2
Chemical		MCL (mg/1)
Arsenic	0.05
Barium	1.0
Cadmium	0.01
Chromium (hexavalent)	0.05
2,4-D	0.1
Endrin	0.0002
Fluoride	1.4-2.4
Lindane	0.004
Lead	0.05
Mercury	0.002
Methoxychlor	0.1
Selenium	0.01
Silver	0.05
Toxaphene	0.005
2,4,5-Trichlorophenoxy	0.01
acetic acid
agency should be contacted to confirm values prior to

Ifcblc 3-3
LV.ir CRiraiA AM)

IE* 01
Allyl alcohol
Alualoua phosphide
Barlun cyanide
BIj (2-«thylbexyl) phthalate
Cacodyllc Acid
(HydroxydlBethylarslDe oxide)
Calclua cyanide
Carbon disulfide
Carton tetrachloride
Chlorine cyanide
l-Chloro-2,3 epoxypropaae
Chroalua (III)
C^roBlux (VI)
Copper cyanide
SI-o-bu tylpbtbalate
DlcblorodlfluoroM thane
1,1 Dlchloroethylene
(Hetbyleoe chloride)
2 £*03
2 EH) 2
Diethyl phtbalate

Table 3-3
IS do thai
Tonic acid
Heptachlor epoxide
Hexacb lorofcutadl «>e
Hydrogen cyanide
Hydrogen sulfide
Isotutyl alcohol
Malelc hydrailde
Methyl etbyl ketone
Methyl ethyl ketone peroxide
(2-Butasone peroxide)
Methyl paratblon
Nickel cyanide
Nitric oxide
Nitrogen dioxide
Osalua tetroxlde
jy rcfc1eroethylene
Phenyl aercurlc acetate
Potasslua cyanide
Potastlui silver cyanide
Pronaalde (Kerb)

Table 3-3

Selenlous add
Silver cyanide
Sllvex (2,4,5-TP)
Sodlua cyanide
IE *00
• E-Ol
Tetraetbyl lead
Ttalllc oxide
Ttalllua acetate
Th&lliun carbonate
TbalHum chloride
Tballlua nitrate
Thalliua seleolte
Tballlua sulfate
acetic acid
V&oadlua peatOKlde
Zloc cyanide
Zinc pboipblde
These preliminary targets are subject to change based on the results
of ongoing Agency review; the regulatory agency should be contacted
to confirm values prior to use.
These values are based on a conversion model that has not received
full Agency review and are, therefore^ subject to change.

Table 3-4
fug/n 1
BIS(cllcrcaetbyllether CBCKE)
Carton tetrachloride
1. JOE-Ol
(Ifclcblorohy drlii)
Chlorooetbyl Methyl Ether fCMHE)
Chroalua [bcxavaleDt)
DlieD: (a ,b)aDthraceoe
l,2-S>ll>roao-3-chloropTopeDe tDBCP)
DlinrtylD ltroiaslDe
1,2-Dlchloroe tbane
1,1 DichloroetliyleTie
Dicn lor oa*t Juse
lHellvyl«* chloride)

Dletbylst llbestrol IDES)
2,4-Dlo it rotolueee
Ethylene oxide
Heptachlor epoxide

feble 3-1
Che* leal
Hydra ill*, Hydrailne Sulfate
Lindane fGasna-Hexaclilorocyclo-
N-Hitroso-N-nethyl urea
Pronaalde (Kerb)
1E-04 4E-03
7E-03 2E-01
tuq/a )
(1>Tbese preliminary targets are subject to change based on tb« results of ongoing Agency
review; the regulatory ageicy should be contacted to conf ir» values prior to use.
Tbese values are based os a conversion aodel that has not reaelved full kgmcy review
and are, therefore, subject to change.

3.	For the surface water route of exposure, target levels
should correspond to human health-based ambient water
quality criteria appropriate for the current or pro-
jected use of the water. (See Table 3-5.)
4.	For routes of exposure involving direct contact with
the soil surface and direct soil ingestion, the target
levels should be based on the RfDs and CPFs as
described above.
5.	For routes of exposure involving inhalation of chemical
contaminants or particulate matter, the target levels
should be based on the National Ambient Air Quality
Standards (NAAQS), where they exist. Where no NAAQS
exist, the target levels should be based on the RfDs
and CPFs, assuming an inhalation route of exposure.
It should be noted that the health-based limits and exposure
assumptions upon which the target levels in Tables 3-2
through 3-5 are based are subject to change, due to ongoing
Agency review. Additional toxicity data and further analy-
sis by the Agency may result in changes to the current
limits and may result in generation of limits for additional
chemical contaminants. The target levels, included in this
document will be revised when necessary. The user of this
document should contact either of the following EPA offices
for current information on health-based limits and for
access to the Integrated Risk Information System (IRIS)
Environmental Criteria and Assessment Office
Cincinnati, Ohio
Office of Health and Environmental Assessment
Washington, D.C.
Preliminary cleanup targets should be set for each hazardous
constituent known or expected to be present in the subsur-
face or in the ground water or surface water and should be
based on each potential route of exposure. The lower, or
most protective, level for each constituent should be used.
As discussed' earlier in this section, if an MCL or health-
based exposure limit does not exist for a particular con-
stituent, background concentration levels may be used for
preliminary cleanup targets. The appropriate use and
limitations of background concentrations for preliminary
cleanup targets is discussed in Section 3.5.
Under a third option, when there are no existing Agency-
established health-based exposure limits, the owner/operator
may wish to submit data for the Agency to determine the

Table 3-5
(from U.S. EPA, 1986)m
VQC (Concentrations Corresponding to
for Potential Careinogens are in
a Risk of 1Q-*
Consumption of
Aquatic Organisms
and Drinking Water
Adjusted for
Drinking Water
Consumption Only(3)
320 ug/1
540 ug/1
0 (58 ng/1)
0 (63 ng/1)
0 (0.074 ng/1)
0 (1.2 ng/1)
146 ug/1
146 ug/1
0 (2.2 ng/1)
(25 ng/1)
0 (0.66 ug/1)
0 (0.67 ug/1)
0 (0.12 ng/1)
0 (0.15 ng/1)
0 (3.7 ng/1)
0 (3.9 ng/1)
10 ug/1
10 ug/1
Carbon tetrachloride
0 (0.4 ug/1)
0 (0.42 ug/1)
0 (0.46 ng/1)
0 (22 ng/1)
Chlorinated benzenes

0 (0.72 ng/1)
0 (21 ng/1)
38 ug/1
180 ug/1
74 ug/1
570 ug/1
4B8 ug/1
488 ug/1
Chlorinated ethanes

0 (0.94 ug/1)
0 (0.94 ug/1)
16.4 mg/1
19 mg/1
0 (0.6 ug/1)
0 (0.6 ug/1)
0 (0.17 ug/1)
0 (0.17 ug/1)
0 (1.9 ug/1)
0 (2.4 ug/1)
Chlorinated phenols

0.2 ug/1
0.2 ug/1 (Organoleptic)

1.0-ug/1 (Organoleptic)
1.0 ug/1 (Organoleptic)
2600 ug/1
2600 ug/1
0 (1.2 ug/1)
0 (1.8 ug/1)
Chloroalkyl ethers

bis-(Chloromethyl) ether
0 (0.0036 ng/1)
0 (0.003? ng/1)
bis(2-Chloroethyl) ether
0 (30 ng/1)
0 (30 ng/1)
bis-(2 Chloroisopropyl)
34.7 ug/1
34.7 ug/1

0 (0.19 ug/1)
0 (0.19 ug/1)
0.1 ug/1 (Organoleptic)
0.1 ug/1 (Organoleptic)
Chromium Cr+6
50 ug/1
50 ug/1
170 mg/1
170 ®g/l
200 ug/1
200 ug/1
0 (0.024 ng/1)
0 (>1.2 ng/1)
Dichlorobenzenes (all
400 ug/1
470 ug/1

Table 3-j
2,4-Dieh 2orophen ol
Hexachlorocyclohexanes (HCCK)
Phthalate esters
Dune thylphtha late
Polychlorinated biphenyls
WQC (Concentrations Corresponding to a Risk of ID
for Potential Carcinogens are in Parentheses)
Consumption of
Aquatic Organisms
and Drinking Water
0 (10.3 ng/1)
0 (33 ng/1)
See Halomethanes
0.3 ug/1 (Organoleptic)
67 ug/1
0 (0.071 ng/1)
400 ug/1 (Organoleptic)
0 (0.11 ug/1)
0	(42 ng/1)
74 ug/1
1	ug/1
42 ug/1
0 (0.19 ug/1)
0 (0.28 ng/1)
0 (0.45 ug/1)
Adjusted for
Drinking Water
Consumption Only
0 (20.7 ng/1)
0 (33 ng/1)
See Haloaethanes
0.3 ug/1 (Organoleptic)
87 ug/1
0 (1.1 ng/1)
400 ug/1 (Organoleptic)
0 (0.11 ug/1)
0	(46 ng/1)
138 ug/1
1	ug/1
188 ug/1
0 (0.19 ug/1)
0 (11 ng/1)
0 (0.45 ug/1)
0 (9.2 ng/1)
0 (16.3 ng/1)
0 (18.6 ng/1)
0 (12.3 ng/1)
206 ug/1
50 ug/1
144 ng/1
13.4 ug/1
19.8 ng/1
13.4 ug/1
70 ug/1
0 (1.4 ng/1)
0 (0.8 ng/1)
0 (6.4 ng/1)
0 (16 ng/1)
1.01 rog/1
3.5 mg/1
313 ng/1
350 ng/1
34 ng/1
0 (0.079 ng/1)
10 ug/1
50 ug/1
0 (13 ng/1)
0 (23.2 ng/1)
0 (18.6 ng/1)
0 (12.3 ng/1)
206 ug/1
50 ug/1
10 ug/1
15.4 ug/1
19.8 ng/1
13.6 ug/1
70 ug/1
0 (1.4 ng/1)
0 (0.8 ng/1)
0 (6.4 «g/l)
0 (16 ng/1)
1.01 ng/1
3.5 mg/1
350 ng/1
434 ng/1
44 ng/1
0 (>12.6 ng/1)
10 ug/1
50 ug/1

Table 3ii:
Vinyl chloride
WQC (Concentrations Corresponding to a Risk of 10"
for Potential Carcinogens are in Parentheses)
Consumption of
Aquatic Organisms
and Drinking Water
0 (0.000013 ng/1)
13 ug/1
14.3 ng/1
0 (0.71 ng/1)
0 (2.7 ug/1)
0 (2.0 ug/1)
Adjusted for
Drinking Water ...
Consumption Only
0 (0.00018 ng/1)
17.8 ug/1
15 ag/1
0 (26 ng/1)
0 (2.8 ug/1)
0 (2.0 ug/1)
These criteria are subject to change; the regulatory agency should be
contacted to confirm values prior to use.
The criterion value, which is sero for all potential carcinogens, is listed
for all chemicals in the table. The concentration valge given in parentheses
.for potential carcinogens corresponds to a risk of 10~ , which is the midpoint
of the range of 10 to 10 given in water quality criteria documents.
These adjusted criteria, for drinking water ingestion only, were derived from
published EPA ambient water quality criteria (45 Federal Register,
pp. 79318-79379, November 28, 1980) for combined fish and drinking water
ingestion and for drinking water ingestion alone. The adjusted values are
not official EPA ambient water quality criteria, but may be appropriate for
use in the evaluation of facilities with contaminated surface water. In the
derivation of these values, intake was assumed to be 2 liters/day for
drinking water and 6.5 grams/day for fish, and human body weight was assumed
to be 70 kilograms. Values for bioconcentration factor, carcinogenic
potency, and acceptable daily intake were those used for water quality
criteria development.
Criteria designated as organoleptic are based on taste and odor effects, not
human health effects. Health-based water quality criteria are not available
for these chemicals.

environmental and health effects of the contaminant in order
to establish the preliminary cleanup target. This is dis-
cussed briefly in Section 3.6.
Final cleanup targets must be established in the air, ground
water, surface water, and soil to account for all possible
routes of exposure such as inhalation, ingestion of drinking
water, and direct ingestion of soil, that adequately pro-
tects human health and the environment. Preliminary cleanup
targets may be modified based on several site-specific fac-
tors described below. For carcinogens, preliminary targets
were set to achieve a risk level range of 10~ to 10~ .
Final target levels established according to procedures
outlined in this section should still maintain a risk level
range of 10~ to 10" . Often, final cleanup targets will
depend on data obtained during confirmation monitoring. The
following factors may be used to modify PCTs to establish
final cleanup targets:
o	Cumulative effects of chemical mixtures
o	Detection limits
o	Environmental impacts
o	Site-specific exposure scenarios
o	Elevated background levels
Based on confirmation monitoring data, it may be necessary
to revise the preliminary target levels to reflect the mix-
ture of chemicals that are present at the impoundment.
Because of the potential additivity of effects of carcin-
ogens and the potential for noncarcinogenic compounds to
cause the same systemic or target organ health effects,
final cleanup targets can be significantly lower. For exam-
ple, if the owner/operator discovers extensive soil contami-
nation upon liner removal, the presence of numerous
compounds that can result in the same health effects will
result in lower ultimate target concentrations than pre-
dicted by preliminary targets. In addition, if more than
one route of exposure is possible, the cumulative effect on
an exposed individual must be taken into account in setting
final target levels.
If more than one constituent is detected in environmental
media at levels at or near preliminary target levels, an
assessment of the cumulative potential risk may be required
(Appendix D). Because preliminary targets have been devel-
oped only for single constituents for single medium consid-
erations (e.g., lead in soils); the presence of more than
one constituent in any one medium (e.g., several heavy metal

contaminants in the soil); or the same constituent in
several media (e.g., lead in soils, ground water, and air)
may represent an unacceptable health risk even if each indi-
vidual constituent is below its preliminary target concen-
tration. The final cleanup target concentrations must be
protective of human health and the environment based on the
cumulative health risks posed by exposure to any residual
contamination, considering additive effects and multiple
route exposures.
As stated previously, final cleanup targets for clean
closure must be protective of human health and the environ-
ment. Because this confirmation must be accomplished with-
out the benefit of post-closure monitoring or site use
restrictions, potential direct exposure health risks must be
evaluated. A qualitative judgment can be made by reviewing
confirmation monitoring data from soils and ground water in
comparison to preliminary cleanup targets. Constituents
with the same toxic effects should be evaluated together.
For carcinogens, if review of the residual concentrations
remaining in soils and ground water indicates the lifetime
cancer risk may exceed 10~ for Class AiB carcinogens and
10~ for Class C carcinogens, the owner/operator must evalu-
ate the additional cancer risk under guidelines presented in
Guidelines for Carcinogen Risk Assessment (Appendix D),
revise the appropriate target levels, and remove additional
soil to ensure the revised targets are met.
For noncarcino'gens and carcinogens that exhibit
noncarcinogenic systemic toxicity, constituents should be
grouped by the same systemic toxicological effects when
these effects are known. If two or more constituents
exhibit the same systemic toxicological effect, an eval-
uation of health risks should be conducted in accordance
with Appendix D (Guidelines for Carcinogen Risk Assessment
and Guidelines for the Health Risk Assessment of Chemical
Mixtures). Final cleanup targets, therefore, must be met
based upon cumulative exposure and potential health effects
before clean closure can be completed.
When final target levels in any medium are below the limits
of detectability, based on currently available analytical
techniques, the final target level could be modified to
equal the detection limit. Since detection limits depend
directly on the analytical technique employed, it will be
necessary for the owner/operator to designate the analytical
techniques to be employed and to obtain approval from the
Agency on the actual detection limits that will be used in
lieu of levels based on health-based standards. This
approval will be accomplished through the preparation and
approval of the QA/QC program discussed in Section 2.6. The

analytical methods selected should be those contained in
Test Methods for Evaluating Solid Waste, SW-846 (U.S. EPA,
1986dJ. Since this document is updated regularly to include
new and revised test methods, the owner/operator is advised
to consult the most recent edition or to contact the
Technical Assessment Branch of the Office of Solid Haste in
Washington, DC, (202/382-4761) for current information on
Agency-approved test methods.
Target levels for any medium (sbil, air, or water) could be
based on the elimination or prevention of adverse effects on
sensitive environmental receptors. Where such environmental
effects are potentially significant for surface water, the
target levels should be based on federally approved State
water quality criteria (for protection of aquatic species)
appropriate for the intended use of the impacted water body.
For this pathway, the assumption is made that a contaminant
in the air, soil, or ground water, in addition to the sur-
face water, could affect an aquatic organism if migration to
surface water was potentially significant.
If an unusual exposure scenario or vulnerable receptor
population exists at a site, more stringent cleanup targets
may be warranted. Conversely, site conditions may dictate
that a less stringent standard would still be protective of
human health and the environment. For example, for the
ground-water exposure scenario, this may be the case if the
potentially impacted aquifer is non-potable and does not
provide a migration pathway for contamination of other
environmental media.
If the owner/operator can demonstrate that elevated
background levels at the site exist due to natural causes or
another man-made contaminant source, the final cleanup tar-
get may be raised to the detected level. The demonstration
must show that cleanup to a lower level than background
would not provide any significant reduction in risk to
actual or potential receptors in the vicinity of the cite.
Background levels must be properly established and docu-
mented in accordance with procedures presented in
Section 3.5.
The owner/operator may use background contaminant
concentration levels for ground water, soil, and surface

water in setting preliminary cleanup targets where no
Agency-established levels exist for a particular contami-
nant. In addition, properly documented elevated background
levels may be used as final cleanup targets in certain
instances. It is critical that levels established as
background be representative of the natural or existing
local conditions that were not affected by operations of the
surface impoundment. Therefore, the owner/operator will
have to document the adequacy of the sampling and analysis
procedures used to determine the background levels. Proce-
dures for the sampling and analysis to determine these lev-
els are discussed in Sections -3.5.1 through 3.5.3.
Chain-of-custody and QA/QC procedures for the sampling pro-
gram are covered in Sections 2.6 and 2.7, respectively.
For those hazardous constituents for which no health-based
standards exist, the use of background levels is acceptable.
In the future, as Agency-approved standards are developed
for more constituents, the use of background levels for pre-
liminary cleanup targets will be less frequent.
For clean closure of surface impoundments, the guidelines
outlined in Section 2.2 of the RCRA Ground-Water Monitoring
Technical Enforcement Guidance Document (U.S. EPA, 1986e) to
develop a ground-water background sampling plan should be
followed as summarized below. For surface impoundments, the
determination of background levels will involve a review of
the in-place ground-water monitoring system and existing
data. Where unsaturated zone migration of waste constitu-
ents is significant, it may be necessary to determine the
potential impact on background ground-water quality of con-
taminants present in the unsaturated zone. This data review
should be included in the closure plan within the site char-
acterization data described in Section 2.0.
The first step in establishing background ground-water
quality is to identify ground-water flow paths by performing
a flow-net analysis. Information related to ground-water
flow should be developed as discussed in Section 2.0. After
this determination is completed, monitoring wells are
installed upgradient to evaluate background concentration
levels of contaminants. Care should be taken in establish-
ing upgradient wells to ensure that the ground water is
unaffected by the closing unit, as a result of variable
flow, pumping, mounding, or highly irregular geologic fea-
tures. The analytical procedures that will be used to
determine background concentrations should be included in
the closure plan.
The background well(s) are placed in an upgradient area of
subsurface strata comparable to that which underlies the

surface impoundment. To assure data comparability and to
obtain the most accurate ground-water chemistry data, the
wells monitoring background levels will sample the same
stratigraphic horizon as downgradient monitoring wells
located on the perimeter of the surface impoundment. It is
assumed that this horizon will be the uppermost aquifer; if
the uppermost aquifer is thought to be hydraulically con-
nected to a lower aquifer, then the sampling has to occur in
both zones. To determine if the wells are far enough upgra-
dient, available water level data should be reviewed. Ade-
quate attention should also be given to lateral and vertical
gradients in each saturated zone and to unsaturated zone
flow. Performing a flow net/flow line analysis (as
described in Criteria for Identifying Areas of Vulnerable
Hydrogeoloqy Under the Resource Conservation and Recovery
Act (U.S. EPA, 1986f), Appendix B—Ground-Water Flow Net/
Flow Line Construction and Analysis, and Appendix C—
Technical Methods for Calculating Time of Travel in the
Unsaturated Zone (July 19B€)) will enable the owner/operator
to determine whether the monitoring system is appropriate
for establishing background ground-water quality.
The number of upgradient wells necessary to determine the
spatial variability in water quality will be determined on a
site-specific basis. The minimum number of background moni-
toring wells is one. If only one upgradient well is used,
sufficient hydrogeologic sampling and analysis information
should be provided to assure that the uppermost aquifer is
essentially homogeneous.
The number of samples to be collected and analyzed depends
on the number of monitoring wells installed. Therefore, the
rationale for the number of wells and samples taken to
determine ground-water background levels should be included
in the closure plan. For each background well, a minimum of
quarterly ground-water samples for 1 year is desirable. The
use of clustered wells is highly recommended, to ensure that
a complete vertical profile of ground-water quality is
obtained throughout the depth of the saturated zone.
3.5.2 SOIL
To determine background levels of soil for a surface
impoundment being proposed for clean closure, it is neces-
sary to collect and analyze background soil core samples
from an area that has not been affected by routine opera-
tions of the impoundment, by accidental or emergency inci-
dents, or by operations of other units at the facility.
For soil core sampling, the area where soil background
levels are measured should be from the same soil horizon in
the same geologic formation as that which directly underlies
the surface impoundment's waste or liner. The closure plan

should specify how the background sampling area should be
determined. Within the area outlined for background deter-
minations/ the specific sampling locations should be
determined using the two-dimensional random-sampling tech-
nique as specified in Appendix B.
The closure plan should outline the sampling method to be
used, number of samples taken, sampling equipment, and basis
of these decisions. To account for spatial variability in
the soil horizons, a sufficient number (no fewer than four)
samples in each distinctive soil horizon should be collected
and analyzed. In many cases, more than four samples will be
Surface water should be sampled upgradient from the surface
impoundment and in an area with no impact from the surface
impoundment. Additionally, sediment sampling upstream from
a point of surface runoff or ground-water discharge to the
surface water body should be undertaken to establish
The number of samples taken should be determined on a
site-by-site basis with the objective being to sufficiently
characterize the surface water and sediment background lev-
els. A minimum of four samples should be taken from each
potential surface water pathway. Because of the flow and
volume variability of surface water sources (streams, ponds,
lakes, etc.), four samples may not be an adequate represen-
tation of the source; therefore, additional sampling may be
required. The surface water and sediment sampling schedule
and procedures should be included in the closure plan along
with specific information on the number of samples to be
taken, frequency, and location.
3.5.4	AIR
Determining air background levels upwind of the surface
impoundment may need to be completed when monitoring for air
emissions is necessary. The owner/operator must consider
air contaminant levels during closure activities such as
soil excavation or performance and confirmation monitoring
and sampling. To protect the health and safety of the work-
ers and surrounding populations, air emission controls may
be necessary during the closure period. Such controls
should be designed to prevent emissions because of volatil-
ization, as well as fugitive dust or particulate emissions.

If no Agency-established exposure limits are available for a
hazardous constituent, the owner/operator may submit toxi-
city test data of sufficient quality for the Agency to
determine the environmental and human health effects. Data
submitted by the owner/operator on environmental and health
effects of a constituent should, when possible, follow the
toxicity testing guidelines of 40 CFR Parts 797 and 798 (50
FR 39252, September 27, 1965). In the event that the Agency
is able to establish exposure limits with data submitted by
the owner/operator, these exposure limits may be used in
establishing preliminary cleanup targets. For assistance in
preparing and submitting adequate toxicity test results, the
owner/operator should contact the Health Assessment Section
of the Characterization and Assessment Division of the
Office of Solid Waste at EPA's Headquarters in Washington, DC
Final cleanup targets must be established by the owner or
operator of the surface impoundment and included in the
closure plan submitted to the Agency or to the authorized
State for final approval. If a closure plan had been
approved previously, without the final cleanup targets, a
modification of the closure plan and re-approval will be
necessary. The Agency will require public notice of the
proposed final closure plan, and will review any comments
received, prior to closure plan approval. It will be nec-
essary, therefore, for the closure plan submitted for Agency
approval to contain an adequate description of the basis for
deriving the final cleanup target. At a minimum, the fol-
lowing information will be required:
o Identification of constituents
o Agency-approved health based level for each
o Exposure assumptions employed
o Basis for calculating each target level
o Methodology for determining cumulative effects due
to multiple constituents or due to multiple expo-
sure routes
o Sampling and analysis data to establish background
levels, as appropriate

o Source of detection limits for standard analytical
methods used, where appropriate
Upon review of any comments received on the proposed closure
plan and the derivation of the final cleanup targets, the
Agency will perform a final review of the closure plan prior
to approval.

U.S. EPA, 1986a, Risk Assessment Forum, ECAO-CIN-475.
U.S. EPA, 1986b, Carcinogenic Assessment Group,
OHEA, EPA/600/6-83/012 FF, September 1966.
U.S. EPA, 19B6c, Guidelines for Estimating Exposure, F.R.
Vol. 51, No. 185.
U.S. EPA, 1986d, Test Methods for Evaluating Solid Waste,
S.W. 846, 3rd Ed.
U.S. EPA, 1986e, RCRA Ground-Water Monitoring Technical
Enforcement Guidance Document, Office of Water Programs
Enforcement, Office of Solid Waste and Emergency
U.S. EPA, 19E6f, Criteria for Identifying Areas of
Vulnerable Hydrogeology Under the Resource Conservation
and Recovery Act, Appendix B—Ground-Water Flow Net/
Flow Line Construction and Analysis, Interim Final
(July 1986J; and Appendix C—Technical Methods for Cal-
culating Time of Travel in the Unsaturated Zone (July

Section 4
As stated in the preamble to 40 CFR 264.22B and 265.228
regarding clean closure (see Appendix A),
"...EPA intends that the terns 'remove' and
'decontaminate* mean removal of all wastes, liners,
leachate, and materials contaminated with the waste or
le&chate (including ground water) that pose a substan-
tial present or potential threat to human health or the
environment...To provide the necessary level of assur-
ance, the Agency will require owners or operators to
remove all wastes and contaminated liners and to demon-
strate that any hazardous constituents left in the
subsoils will not cause unacceptable risks to human
health or the environment."
Figure 4-1 depicts a sequence of the closure steps that must
be carried out to achieve clean closure as it is defined in
the regulations. The order of steps may not be appropriate
for every site, and many of the steps are interrelated so
that they cannot be accommodated in a generalized procedure.
Therefore, it is important to understand the applications
and limitations of each of the major closure steps discussed
in this secti6n, as well as the selection and use of alter-
native methods and equipment to complete each step. The
closure steps indicated in Figure 4-1 are discussed indi-
vidually in Sections 4.3 through 4.8 below. In addition,
preparation of a site safety plan is addressed as a first
step in Section 4.2, and guidance on providing air emission
controls throughout closure is presented in Section 4.9.
Section 4.10 lists useful references relevant to these
closure activities.
Each of the sections below provides the regulatory background
for the subject closure step, lists the relevant information
the owner or operator should submit to the Agency in the
closure plan, and identifies several important considerations
the owner or operator and Agency reviewer should address in
preparing and reviewing the closure plan.
From a technical perspective, this section does not address
onsite treatment options in depth, nor does it cover offsite
waste shipment, treatment, storage, or disposal. Appendix E
presents relevant closure plan information requirements and
evaluation factors on these topics that are applicable to
each of the closure steps described below. Finally, the

Figure 4-1
Source US EPA, 1985(MotJrfied)

discussion does not extend beyond removal of contaminated
materials, since having progressed that far would constitute
clean closure.
A site safety plan that establishes policies and procedures
to protect workers and the public from the potential hazards
posed by excavation of hazardous materials must be developed
before site activities proceed. The site safety plan should
provide measures to prevent accidents and injuries that may
occur during normal daily activities or during adverse
weather conditions.
Development of a written site safety plan helps ensure that
all safety aspects of site operations are thoroughly
examined prior to commencing field work. The site safety
plan should be modified as needed for every stage of site
activity and whenever new information about site hazards is
obtained. The site safety plan must, at a minimum, address
the requirements of the December 19, 1986, OSHA regulations
for hazardous waste operations (29 CFR 1910; 120, Federal
Register, Vol. 51, No. 244, pp. 45654-45675).
The reader should also consult Chapter 3 of the Occupational
Safety and Health Guidance Manual for Hazardous Waste Site
Activities IN10SH, 1985) for more detail on the topics
addressed below. Sections 4.2.3 and of the Guidance
Document for Cleanup of Surface Impoundment Sites (U.S. EPA,
1986) also contain useful information concerning site safety.
A preliminary 6ite safety plan should be developed so that
the initial sampling and analysis (see Section 2.0) can pro-
ceed in a safe manner. The information from initial sampling
and analysis can then be used to refine the site safety plan
so that further closure activities can proceed safely.
This section should be used as a guide, not a standard, for
designing a site safety plan.
At a minimum, the site safety plan should include the
following information:
o List names, addresses, and telephone numbers of
key personnel and alternates responsible for site
o Describe the risks associated with each operation

o Confirm that personnel are adequately trained to
perform their job responsibilities and to handle
the specific hazardous situations they may
o Describe any site-specific personnel medical
surveillance program, including initial and periodic
follow-up physicals.
o Describe the protective clothing and equipment,
including respirators, to be worn by personnel
during various site operations.
o Describe any onsite or offsite air monitoring.
o Describe the actions to be taken to mitigate
existing hazards (e.g., containment of contaminated
materials) to make the work environment less
o Define site access control measures and include a
site map.
o Establish decontamination procedures for personnel
and equipment (see Section 4.6, Equipment
o Document the site's standard operating procedures,
(i.e., those activities that can be standardized,
such as decontamination and respirator fit
testing, and where a checklist can be used).
o Set forth a contingency plan for safe and effective
response to emergencies.
Much of the above information is already required by
Subparts B, C, and D of Part 264 of RCRA, and should be
easily obtainable by the owner/operator.
Removal of all hazardous wastes at closure is a key element
of demonstrating "clean closure," as discussed in the
preamble to 40 CFR 264.228 and 265.228. The first step in
the waste removal procedure is the removal of any standing
liquid. This liquid generally occurs as a layer above the
waste solids and is comparatively free of suspended solids.
Removal of this liquid is normally necessary before the
residual solids can be removed or before sediments/sludges
can be dewatered. In most cases, this liquid must be
A - A

managed as a hazardous waste, unless it meets the criteria
of 40 CFR Part 261.3 (d).
The reader should refer to Section 4.1 of Closure of
Hazardous Waste Surface Impoundments (U.S. EPA, 1982) and
Section of the Handbook on Remedial Actions at Waste
Disposal Sites (U.S. EPA, 19B5a) for information on liquid
removal methods.
The owner or operator 6hould include the following
information on liquid removal in the closure plan:
o Maximum anticipated volume of waste liquids and
sediments/sludges in the impoundment at closure,
taking into account waste being stored or treated
elsewhere onsite that is destined for the
o Characterizations of both the waste liquids and
sediments/sludges with respect to hazardous con-
stituents and their concentrations. (See
Section 2.0.)
o Description of any liquid waste treatment steps to
be employed in the impoundment prior to liquid
removal, including types and amounts of chemicals
to be added, reactions anticipated, types and vol-
umes of products expected, equipment and procedures
to be used, and time required.
o Description of the liquid removal techniques to be
employed, including necessary equipment, capacities,
procedures, and time.
o Description of any onsite treatment process to be
used after liquid removal, including necessary
equipment, capacities, procedures, reagents,
reactions, products, volumes, and time. (See Appen-
dix E for a discussion of information requirements
and evaluation factors relating to onsite treatment
and offsite shipment.)
As discussed in the preamble to 40 CFR 264.226 and 265.228,
the RCRA regulations governing clean closure require removal
of all wastes from the surface impoundment. Waste
sediment/sludge removal should occur before and separate

from impoundment liner removal to ensure that the liner's
integrity is maintained and that leakage of waste or
leachate to the underlying soils prior to the excavation
process is prevented.
The reader should refer to Section 4.2 of Closure of
Hazardous Waste Surface Impoundments (U.S. EPA, I9B2) and
Section 7.1 of the Handbook on Remedial Action at Waste
Disposal Sites tU.S, EPA, 1965a) for a more detailed
discussion of excavation procedures.
Owner or operators should provide the following information
regarding waste sediment/sludge removal in their closure
o Physical and chemical characterization of the
sediment/sludge, including viscosity, water content,
and contaminant concentrations, that is as represen-
tative as possible of the actual vertical and hor-
izontal change in these parameters in the
impoundment. {Sampling to full depth may lead to
further contamination where there is a clay liner
or no liner: see Section 2.1 for methodology.)
o Description of any onsite sediment/sludge treatment
proposed before or after removal from the impound-
ment, including information on equipment, proce-
dures, capacities, volumes, reagents, reactions,
products, and time necessary.
o Description of the equipment, capacities,
procedures, and time necessary to remove the
sediment/sludge from the impoundment.
o Description of how waste sediments/sludges will be
removed in such a manner that will preserve the
integrity of the linez as much as is possible to
minimise subsoil contamination prior to the excava-
tion and liner removal process.
o Where dry excavation processes are used, assessment
of the possibility of water accumulation from
rainfall. Description of scheduling of the excava-
tion process to confine excavation operations to
small areas that can be cleaned up and diked off,
thereby preventing rainfall runoff from the
remaining sediments/sludges into excavated areas.
o Description of how the liner will be inspected
after sediment/sludge removal for breaches and
possible leakage; this will enable the subsequent

subsoil sampling plan to be adjusted to focus on
areas of possible leakage.
o The reader should see Appendix E for a discussion
of information requirements and evaluation factors
relating to onsite treatment and offsite shipment.
As stated in the preamble to the closure regulations, removing
contaminated portions of the liner is a key step in achieving
clean closure. (Note that 'contaminated portions of the
liner" is interpreted as all of a synthetic liner and the
contaminated thickness of a clay liner.) In addition, in
cases where the closed surface impoundment site vill be back-
filled and returned to some suitable use, complete liner
removal is probably necessary to avoid creation of an arti-
ficial subsurface water reservoir that could affect the sur-
face load bearing capacity of the soil.
Liner removal should occur after, and separate from, waste
sediment/sludge removal to preserve liner integrity and to
minimize any further subsoil contamination caused by leakage
of waste or leachate through breaches in the liner.
Similarly, liner removal should occur before, and separate
from, subsoil removal to minimize the potential for
contamination of the subsoil by hazardous constituents on or
in the liner. The manual user should refer to Section 4.4
of Closure of Hazardous Waste Surface Impoundments (U.S.
EPA, 1982) for more guidance on liner removal.
The following information on liner removal should be included
by the owner or operator in the closure plan:
o Liner type, composition, manufacturer, thickness,
and age.
o Brief description of original liner installation
procedure, including seaming and QA/QC checks.
o Brief description of any liner maintenance and
inspection performed after installation and an
assessment of liner condition at the time of
removal. This description could help to identify
potential areas where leakage may have formerly

o Area and volume of liner to be removed. The
closure plan should include provisions for removal
or decontamination of the entire thickness and
areal extent of the contaminated portions of the
liner (i.e., all of a synthetic liner and the
contaminated thickness of a clay liner); otherwise,
the impoundment xoay have to be closed as a
o Description of liner removal equipment and
step-by-step procedures, such as processing areas,
disposal method, end Any decontamination, if
o Descriptions of precautions that will be taken to
prevent contamination of underlying soils. The
owner or operator should conduct an inspection
prior to liner removal to check for and remove any
waste residue remaining after the sediment/sludge
removal step. (As previously discussed, the
inspection should also check for and record the
location of breaches in the liner to guide subse-
quent subsoil sampling and analysis.) Care should
be taken during liner removal to minimize mixing
of contaminated liner materials with the subsoils.
o The reader should see Appendix E for a discussion
of information requirements and evaluation factors
relating to onsite treatment and offsite shipment.
The RCRA regulations for clean closure of surface
impoundments (40 CFR 264.228 and 40 CFR 265.228) require
"...owners or operators to remove all wastes and contaminated
liners and to demonstrate that any hazardous constituents
left in the 6ubsoils vill not cause unacceptable risks to
human health or the environment." Section 3.0 of this manual
describes how to establish 6oil cleanup targets that are
consistent with the clean closure standard. Section 4.7
describes methods of soil testing "to measure cleanup progress
during 6oil excavation and removal, and Section 5.3 addresses
soil cleanup confirmation testing.
Contaminated subsoils should be excavated and removed
separate from and after waste and liner removal to minimize
contamination of additional subsoils.
The reader should refer to Section 7.1 of the Handbook on
Remedial Action at Waste Disposal Sites (U.S. EPA, 1985a)

and Section 4.2 of Closure of Hazardous Waste Surface
Impoundments (U.S. EPA, 1982) for information on contaminated
soil excavation methods.
The clean closure plan should include the following information
and estimates regarding soil excavation and removal:
o A map or site plan shoving the locations of all
known or potential contamination areas on the site.
o A list of contaminated areas identified on the map
including the probable surface area, depth, and
nature of contamination, as well as the type of
evidence used to identify the area.
o The probable total area and volume of 6oil to be
excavated based on the preliminary target levels
indicated in the closure plan, and based on any
revised target levels corresponding to subsequent
waste and soil analyses.
o A brief description of the excavation and removal
equipment and procedures to be used, including
staging areas.
o A schedule of excavation and removal activities,
by contaminated area.
o Procedures for soil testing during excavation.
(See Section 4.7.)
o The reader should see Appendix E for a discussion
of information requirements and evaluation factors
relating to onsite treatment and offsite shipment.
Upon removal of the surface impoundment's waste and liner(s),
and removal of the bulk of the most highly contaminated
soils, a soil sampling and analysis program should be
implemented to determine the extent of contaminant migration
to the underlying soils from the impoundment. This sampling
and analysis program should continue through the cleanup
phase of the surface impoundment to monitor when and where
contaminant cleanup targets are met and to ensure that no
localized areas of elevated concentrations have been
overlooked during the excavation process.

The soil sampling and analysis plan should be included in
the closure plan; the results from this program will be a
key element in determining when the confirmation monitoring
program should be implemented to certify clean closure. For
more information, the manual user may consult Section 4.5 of
Closure of Hazardous Waste Surface Impoundments (U.S. EPA,
19B2) and Sections 4.4.4 and 4.4.5 of the Guidance Document
for Cleanup of Surface Impoundment Sites (U.S. EPA, 1986).
The first phase of the soil sampling and analysis program
should.include a complete evaluation of the soils underlying
the surface impoundment. Initially, a visual inspection of
the soils should be completed to assess any abnormalities
(i.e., discolored soils, odors) within the area. These
abnormalities might indicate contaminated areas (referred to
as "hot spots"). Upon completion of the visual examination,
a sampling plan should be implemented to sample the possible
"hot spots" and the surface impoundment area as a whole.
For the soils underlying the entire surface impoundment,
soil core samples (using a split spoon sampler) should be
collected with the sample locations determined using two-
dimensional random sampling (described in Appendix B).
Separately, the potential "hot spots" should be sampled to
determine if these areas are actually contaminated.
Using the random sampling methodology, the owner/operator
will collect a minimum of four samples for each quadrant in
an area of 10,000 square feet or less. For possible "hot
spot" areas, one sample for each quadrant in an area of
2,500 square feet or less should be sampled and analyzed.
It is necessary to remove additional soil that has been
determined by the first phase of sampling and analysis to
have contaminant levels above the target levels. The soil
should be excavated in a logical, layer-by-layer sequence
unless it becomes obvious, based on the visual inspection
and the sampling to identify "hot spots," that layer-by-
layer removal is inappropriate. In many cases, contaminant
migration may not be uniform throughout a soil horizon, but
may have followed macropore channels (or fractures) or other
avenues of high effective porosity. In such cases, a more
directive soil excavation approach would be more appropri-
ate. The thickness of each layer to be removed should be
indicated in the closure plan with the soil sampled and
analyzed after each layer is removed. As areas are deter-
mined to be within the established cleanup target levels,
the excavation and removal program will focus on smaller
contaminated areas of the impoundment. Therefore, the soil
sampling and analysis program should be readjusted to
account for the smaller cleanup areas.

The time necessary to complete the soil excavation process
should be an important consideration. The site should be
excavated as rapidly as possible to lessen the possibility
of a precipitation event that will transport contaminants
through the unsaturated zone. The owner/operator is
responsible for scheduling and planning the excavation to
limit the occurrence of this potential situation.
The soil grab samples collected should be analyzed for the
hazardous constituents determined to be present during the
waste characterization phase. (See Section 2.1.) Soil grab
samples should be analyzed using total digestion techniques
and the appropriate leaching procedure. Chain-of-custody
and QA/QC procedures apply to all sampling and analysis com-
pleted during this phase; these procedures are discussed in
Section 2.6 and 2.7, respectively.
The following information relative to soil testing during
excavation should be included in the closure plan:
o Description of soil sampling and analysis
methodology and procedure
o Rationale for number of samples, location, and
frequency, which should be determined on a site-
specific basis
o Depth of soil cores and concentration profiles for
all contaminants of concern
o Procedures to readjust the sampling procedure when
contaminant "hot spots" are located
o QA/QC and chain-of-custody procedures to be
All contaminated items such as equipment, tools, supplies,
and used protective garments that are involved in operating,
maintaining, and closing the surface impoundment must be
decontaminated or removed to an approved hazardous waste
treatment, storage, or disposal facility to meet the clean
closure standard. The reader should refer to Chapter 10 of
the Occupational Safety and Health Guidance Manual for
Hazardous Waste Site Activities (NIOSH, 1965), and the Guide
for Decontaminating Buildings, Structures, and Equipment at
Superfund Sites (U.S. EPA, 1985b) for more guidance on
equipment decontamination.

A decontamination plan should be developed as part of the
site safety plan (see Section 4.2) and set up before any
personnel or equipment may enter areas where the potential
for exposure to hazardous substances exists. The decontami-
nation plan should address:
o Procedures to prevent contamination of clean areas
or further contamination of equipment.
o The types and concentrations of contamination to
be addressed. The extent of contaminant permeation
of materials should be considered; relevant factors
to address include contact time, concentration,
temperature, size of contaminant molecules and
pore space, and physical state of wastes.
o A list of equipment to be decontaminated,
including personal protective gear, large
equipment, and vehicles.
o The number and layout of decontamination stations.
o Decontamination equipment needed. Decontamination
equipment selection should also consider that same
equipment's suitability for decontamination or
o Decontamination methods to be used. The selected
methods must be compatible with the hazardous
substances being removed and with the clothing or
equipment being decontaminated; the methods must
not pose a direct hazard to closure workers.
o Methods of testing for the effectiveness of
decontamination. (See Section 5.6.)
o Methods and procedures to minimize worker contact
with contaminants.
o Emergency decontamination procedures.
o Description of the anticipated composition and
volume of decontamination residues (e.g., spent
wash solutions and used personal protective gear).
o Description of measures to collect, contain, and
handle decontamination residues as hazardous wastes
in compliance with RCRA and the clean closure

o The reader should see Appendix E for a discussion
of information requirements and evaluation factors
relating to onsite treatment and offsite shipment.
Closure of hazardous waste surface impoundment sites may
produce gaseous emissions and fugitive dusts containing haz-
ardous constituents.
Gases nay be emitted by the vaporization of liquids, the
venting of entrained gases, or the chemical and biological
reaction with solid and liquid waste material. Volatile
organics, therefore, may be released slowly but continuously
from surface impoundments; the process could be accelerated
during waste removal during closure.
Fugitive emissions are particulates that are lifted from the
ground by means of one or more of the following processes:
o Hind erosion of exposed waste materials
o Reentrainment of particulate matter by vehicular
traffic on haul roads and exposed surfaces
o Excavation of waste materials during closure
The manual user should refer to Section 4.9 of Closure of
Hazardous Waste Surface Impoundments (U.S. EPA, 1982) and
Section 4 of the Handbook on Remedial Actions at Waste Dis-
posal Sites (U.S. EPA, 19B5a) for more information on air
emissions control during closure.
The owner/operator should provide the following information
regarding air emission control in the clean closure plan:
o Waste characterization by phase (i.e., liquid,
sludge, contaminated soils, etc.) with respect to
volatiles and fugitive dust emission potential
o Identification of closure work steps or activities
that will potentially generate hazardous air
o Description of volatiles and fugitive dust
emissions controls corresponding to each closure
work step or activity

4.10.1	GENERAL
Air sampling and monitoring guidelines for hazardous waste
surface impoundments are in the process of being prepared by
U.S. EPA. In the meantime, the guidelines for the Air Con-
firmation Sampling and Monitoring Program will be extracted
from Michigan's Ambient Air Monitoring Guidelines for Act 64
Facilities (Michigan Department of Natural Resources, 1986).
The South Coast (California) Air Quality Management District's
Guidelines for Implementing Rule 1150.1 {SCAQMD, 19851
contains additional information.
The surface impoundment facility must have an air monitoring
network if volatiles and/or particulates are present. Based
on contaminants that may be present in some surface impound-
ment gas, certain samples must be analyzed for hazardous air
Michigan's Ambient Air Monitoring Guidelines for Act 64
Facilities is paraphrased in the following paragraphs.
Although these are not required under RCRA, they are
presented as an example of the considerations to be
addressed for an adequate air monitoring program.
The number of samplers should be determined on a case-by-case
basis, as will the parameters and limits of the air monitor-
ing network.
At least one monitor should be sited to measure the highest
predicted concentration. For ground level sources, the use
of representative meteorological data will determine the
predominant wind direction. Monitors should be sited,
downwind along the perimeter of the facility (property
line). They must also be located off company property
unless it is demonstrated that onsite monitoring represents
ambient air. For elevated sources, dispersion modeling
should be used to determine the maximum impact point.
Background monitoring may also be necessary. Background
samplers should be sited upwind for the predominant wind
Additional offsite monitors may be required to determine the
impact of the source on nearby residents. If receptor
monitoring is appropriate, the monitor should be located in
the direction of the nearest human receptor.

Actual siting of the air monitoring probes should follow the
criteria listed below:
o Locate the sampler in an area that has
unobstructed airflow, especially from the
direction of the source. The distance between the
nearest obstruction and the sampler should not be
closer than tvo times the height of the
o Locate the sampler at least 20 meters from trees.
o Avoid locations where reactive surfaces may cause
chemical changes in the air samples. For partic-
ulate measurements, there should be vegetative
ground cover or a paved surface.
o Place the intake probe 3 to 5 Deters above ground
o The probe should extend at least 2 meters from the
supporting structure. If the probe is located on
a building, it should be mounted on the windward
At or near the beginning of the program, a period of
intensive sampling will be required. During this period,
samplers must, operate on a 3-day schedule. This period must
include the season of greatest predicted impact from the
source. At the end of 6 months, the owner/operator may
request a relaxation of the sampling frequency to a routine
6-day sampling schedule. A reduction in sampling frequency
will not be approved if documented standard operating proce-
dures have not been followed or if the company has failed a
quality assurance audit. Both the initial intensive and
eventual routine sampling schedules must coincide with the
EPA TSD monitoring schedule.
The owner/operator should develop an air monitoring plan, as
necessary, and submit it with the closure plan for approval.
The monitoring plan shall include the following information:
o	Monitoring objective
o	List of parameters and associated limits
o	Number of samplers
o	Location of monitors
o	Sampling schedule

o Timeliness of sample analysis
o Data reporting requirements
o Overview of sample collection method including
performance parameters such as sample flow rates
and sampling periods
o Overview of sample analysis including performance
parameters such as detection limits and the preci-
sion and accuracy of each method
o Target dates for completing each phase of the
o Identification of key personnel
During closure, the air should be monitored at least once
per month or more frequently depending on the closure activ-
ities (i.e., during waste removal or soil excavation) and
the type of contaminants (i.e., if volatiles are present,
more frequent monitoring may be necessary). The number of
samples collected will depend on the area of the surface
impoundment. The surface impoundment area will be divided
into grid areas such as those discussed in the soil core
sampling section ( One air sample will be
collected using the two dimensional random sampling
methodology from each grid.
An air monitoring system will be placed downwind along the
perimeter of the surface impoundment property line. Addi-
tional monitors must be placed off property to measure ambient
air standards.

Michigan Department of Natural Resources, 1986, Ambient Air
Monitoring Guidelines for Act 64 Facilities.
NIOSH, OSHA, USCG, U.S. EPA, 1985, Occupational Safety and
Health Guidance Manual for Hazardous Waste Site Activ-
South Coast Air Quality Management District, 1985,
Guidelines for Implementing Rule 1150.1
U.S. EPA, 1982, Closure of Hazardous Waste Surface
Impoundments, SW-873.
U.S. EPA, 1985a, Handbook on Remedial Action at Waste
Disposal Sites (Revised), EPA/625/6-85/006.
U.S. EPA, 1985b, Guide for Decontaminating Buildings, Struc-
tures, and Equipment at Superfund Sites,
U.S. EPA, 1986, Guidance Document for Cleanup of Surface
Impoundment Sites, OSWER Policy Directive No. 9380.0-6.

Section 5
The confirmation monitoring and sampling program will be
implemented after removal of surface impoundment wastes,
liners, and soils to ensure that final contaminant cleanup
targets are met. In Sections 5.2 through 5.4, the monitor-
ing and sampling programs are divided into ground water,
soils, and surface water, respectively. Evaluation of
equipment decontamination is discussed in Section 5.5. As
previously discussed in Sections 2.6 and 2.7, QA/QC and
chain-of-custody procedures should be established and
followed for all sampling and analysis programs, including
performance and confirmation sampling.
The objective of these monitoring and sampling programs is
to acquire sufficient environmental media sampling data to
assure that clean closure goals have been met. Sufficient
sampling and analysis must be performed to assure the Agency
that no residual contamination in excess of the final
cleanup targets remains after closure. Therefore, it is
necessary to collect the optimum number of samples to ade-
quately represent the environmental media being sampled.
The sampling methodology for each of the media will allow a
variety of differing site conditions and factors to be taken
into consideration, such as soil type, potential contaminant
mobility, depth to ground water, and flow conditions. It
should be emphasized that clean closure will not be certi-
fied as complete until the EPA or authorized state personnel
have performed an onsite inspection and have verified that
sampling analytical procedures are proper and that final
cleanup targets have been met.
The objective of the ground-water confirmation monitoring
program is to assure that final ground-water cleanup targets
for hazardous constituents are not exceeded either at the
time of completion of closure activities or at any time in
the future. If ground-water contamination in excess of the
Subpart F standard (40 CFR 264.92) for any Appendix IX con-
stituents is determined to have occurred and is attributable
to the operations of the impoundment, clean cloture cannot
be completed until corrective action has been performed.
The monitoring and sampling plan for ground water to be
included in the closure plan should follow guidelines docu-
mented in RCRA Ground-Water Technical Enforcement Guidance

Document (TEGD) (U.S. EPA, 1986a). An overview of the major
points of this document is outlined below.
Before sampling begins, contaminants of concern will be
determined (see Section 2.2); sampling technique(s) will be
based on this determination. The rationale for using spe-
cific sampling techniques should be included by the owner/
operator in the closure plan. In addition, the laboratory
analytical procedure(s) to determine concentrations of con-
stituents from the samples will be referenced in the plan.
As specified in 40 CFR Parts 264 and 265 and in the TEGD,
the owner/operator is required to have in place an adequate
number of monitoring wells to guarantee, to a reasonable
degree of certainty, that any significant leakage of con-
taminants will be detected. Monitoring wells are placed
downgradient of the site as close to the boundary of the
surface impoundment as is reasonable. Spacing for monitor-
ing wells is determined on a site-specific basis. The fac-
tors used to determine this spacing include items such as
flow direction, aquifer homogeneity, permeability, and gra-
dient. Justification of decisions made as to the number and
placement of wells should be included in the closure plan.
The location, depth, and completion intervals of existing
monitoring wells need to be evaluated to determine if they
are adequate to fit the needs of confirmation monitoring and
sampling programs, if these wells are being considered for
use during closure. Well installation documentation and the
rationale of using these wells will be required in the
closure plan.
The closure plan should include sampling and analysis
history of the in-place monitoring wells before the start of
clean closure operations. During the closure operation,
samples from each well will continue to be taken quarterly,
with final samples taken to confirm clean closure. The
withdrawal procedures and subsequent analysis of these sam-
ples should follow the TEGD procedures. The closure plan
should consider field analyses and laboratory analyses to be
completed. The plan should outline procedures and methods
for sample collection and handling and for sample
Upon final closure of the surface impoundment, the soil
within the area of the impoundment and any adjacent areas
where contaminants may have been present as a result of the
operations of the impoundment will be sampled and analyzed
to verify that contaminant levels do not exceed the final
cleanup targets set for clean closure. Soil core samples
are to be collected at random sampling points (see

Appendix B) over the total surface impoundment area and at
areas where known "hot spots" had existed.
The number of samples to be collected should be determined
following the number of samples guidelines specified in
Section 4.7 (Soil Testing During Excavation). The rationale
of the owner/operator in choosing the number of samples,
frequency, and sampling locations for the soil confirmation
testing should be presented in the closure plan. Further
guidance on determining these factors is presented in Unsat-
urated Zone Monitoring for Hazardous Waste Land Treatment
Units (U.S. EPA, 1984).
The samples should be analyzed to assure that final target
levels for soils, based either on direct soil ingestion or
on leaching to ground water and eventual ingestion of
drinking water, are met. To accomplish this assurance, it
will be necessary to perform a total constituent analysis
based on an acid digestion procedure such as Method 3050 of
Test Methods for Evaluating Solid Waste (SW-846)(U.S. EPA,
1986b). Tests for individual constituents (also included in
SW-846) would be performed, as appropriate, based on the
Appendix VIII constituents for which target levels had been

Fader*)	/ Vo! 51 No 1&5 / Wed-eiday S^pte-bf 24 1966 I Nc;!ai
Qjtdeil/vM for C4rt»« U S Environment*)
Protecuoo Agency la today taauing five
guideline! for aliening the health naka
of environmental pollutanta Thnt vt
Cuidelmea for Carcinogen Rjk
Cuidtlmei for Eaumatlng Eipoaum
Guideline! for Mutagenicity Riak
GuideUnet (or the Health Aaaeaament of
Suipect Devefopmemal Toucaau
Cuidelmea for the H«lih Riak
Ajeenoent of Cbrmjc4l Milium
T\ji ooec* tonuinj the Guidelinei for
Carcinogen R.ik Aaieuaeot the other
guideline! ippeLr eieewhere u lod»yi
FadaraJ Regular
Tbt Giudelinei for Carcinogen Rjik
Ajienment (hereif!er "Guidellnee ') art
Intended to guide Aweary evaluation of
aujpeel carcinogen! m lire with the
policjn and procedure! eitablnlved in
the iiir-jtM admirunere^ by the EPA.
Tbete Guideline! were developed •»
pan of an interoffice guideline!
dev elopaie n proyix under the
anpicei of the Offo* of Heilth end
I/H-jonmentaJ A*»eiiment (OHE.A) In
the Agency i OfSce of Rric arch ud
Development. Tbey reQast Agency
conjiderenon of public and Science
Advuory Board I5AJ) comment* on the
Propoaed Guideline! for Carcinogen
Rjil Aiieifsent publ.ihed November
23 1964 [49 FR 46264)
Tbn publication oomplefei (he flrat
round of rvik aiieument guidelines
development Tbeie Gwdelwai will be
rrvued. tad nJA:-6a8fl.
MniJiiinijr mwowmatwk Ln 1MJ
the Nitionei Academy of Science*
(N'ASi pubbihed iu book enotled Risk
Auettmeni  appropriate
Interpretation to uaeit nak. The
fujdelnei aJw itren that thja
in/ormaUor wiU be fuliy pre tented in
Agency nk aneiisent document! and
that Agency icienuiti *itl identify the
ao^nfthi and »cak.teiiei of each
aneiirsent by deicnbirg unceriaintiei
anumpuoru and lm.'.anona ai weU ai
the acienLfic bai i a:d rationale for
•ach aneaameoL
Finally the fuideLnei are fonaulated
to part to bnd|e gap* ui nak aautimest
^toethodoloiy aod data By identifying
theee gapa and the importance of the
ajiimg in/onsation to the nak
aiaeaizeni proceaa EPA wi&hea to
mcounge rtaliarcb and anaJyeia that
will lead to •*** nik UMaastest
aeihoda and data
GuidalioM for CairiaofM Itiak
Work on the GuideLnea for
Carcinogen Rjik Aaietimcdt b«|aa la
January IBM Draft (uidelinci wert
developed by Agency work groupa
coffipoaed ol e»pen acientiata {rota
throughout the Agency Tbe drafu wert
peer-reviewed by ttpen acientiata In the
field of carcifiOfenem from univertibai.
•nvironaental froupi mduatry labor,
and other governmental agenciet Tbey
were then propoaed for public comment
in the Fadanl Repitet |«9 FR «62M) On
N'ovenbeil 1M4 the Admiruitrator
directed that Agency ofTicei uae the
propoaed puidelmei in performing nak
aiMiimenn unnl final guideliMi
K*come available
A.''e' 'Jie doae of Lhe pubiic cor.-er*
persd Agency naff prepared
aum.T.anea of the comment and
ana.'yiei of the maior laauet preier.'ec
by the conunenton and p*opoied
change! in the language of tne
gudcjiei to deal with the iaiuei ra.ied
Thrie analyaei were prvaer.'.ed u
review paneli of the SA£ on Marth 4
and ApnJ U-23 IMS and to the
Emcuuv* Committee of the SA£ on
Apr.! 2V20.19&S The SAB mee^Jtgi
were announced m the Federal Reciter
aa followa February 12. IMS (SO FR
Mil) and Apnl «. 19&S (30 FR IK20 and
ln a letter to the Adairuatrator dated
June IB 1BAS the Exacuuve CommiMee
generally coocurrad en all five of the
yuidelmea but reconusended certain
rvviaioni and rtqueated that any
rvviaed gujddinei b« aubautted to the
appropnate SAB review panel cKairr.an
for review and concurrence on behalf of
the E»eeuuve Committee Aa deacr.bed
Is the rraponaea to coomiinu (tee Pan
B Reiponae to the Public and Science
Aduaory Board Commenul aach
lujdelmei document wet reviied. where
app*opnate. eanautent with the SAB
rtcommendauona and remaed draft
gtudelinei were aubmitted to the panel
chairmen. Reviaad draft Gutdeltnei fcr
Carcinogen Riik Aiienment were
concurred on in a letter dated February
7.19M Copiea of the letter* are
available at the Public Information
Reference Una EPA Headquirere
Librar) ai indicated eliev. here l-. thu
Following thia Preamble are two pant.
Pan A contain! the Cuidelinea and Pan
B the Reipor.ie to the Public and
Science Adtnory Board Commenti (a
lummar) of the mi tor public tommer.ti.
SAB commenti and Agency reaponaei
to ihoie cotnmrntil
The Agency ie conunuing to atudy the
nak aiieaemcnt taiuea raned tn the
fuidrlinei and will revue thaae
guidelmei in line with new information
aa appropnata
Refertncea tupporung document!
and commente received on the propoaed
yuidelmei aa well ai copiea of the final
guidtiinai art available for inipection
and copying at the Public Wormauon
Reference Unit ISE-Mi-MMI EPA
Headquarter* Library W1 M Strtet.
SW . Waihmgton DC beiween the
bourt of 100 a tn and 4 >0 p ov
I certify that theie Cuideiinei art not
Biaior rulei ai defined by Executive
Order 12271 became they are
oonbinding policy atatementi and have
eo direct effect on the regulated
comraututy Therefore they will hate no
affect on coati or pncei and they will

T*6ertJ R»*j*ter / Voi II No US / Wtdntdiy Sofrr.b«T J4 IMe / Ncoeei

k*»» no cLS*.*»4?;ir,cjnf tivtnf Uftc'.r
or the rccncn- j Tim Cjideid tt »«-i
ftmi»rd by ihe orrw of Maiufemam
tni Btidgti j/iitr Extcuu»e Order
Dl'«C 'd|wii 11 9M1
Im M TVouk
fir A Carbon for Car.ll»|W. Eak
/ Ininotfi/Ctiori
II	Hour* SOtntifiaatien
A 0»tr»i»w
B tlrmtrn or Hi ldfnUf>ejtioB
1 Pt-jucjl Chfr^cjl Properties tn£ Route*
end Ptitrmi of CipOiurt
£ Sl^CiwW Aciinr} Rf 11 nonihip*
1 Kfiboi't tnd ftiiTOicotLnnit
4 Te>ieB'ofic Lhti*
t Shan T«nr Ttm
& lx>M Tt^h Ajtsiim! 5u1j«»
t Hitr.«r, Stjditt
C *ti|*" gfttidinu
D Cd'tftnci for Do»f Rttpcnm Attntartii
L Sanvtit") *fij Zone..won
Hi Dei# Amwm	Lipotvrt
Aurtftri 0*?/Lti Cfi6ncxrit.ati0n
A Oew RtlpCBH AjMIIVtril
1 &«peiuPT
C R'ik C-t'tc-t'tti.c.i
1 Opuom far Vifnirul JL(k £*tuntitt
I Cocirumri £ipo»tm
1 Sjrjir) «f Kj»k Ch*r«citntanen
/V CP* Ctou 'tte'-scr- in'rjn for
Ccrr|s-f| K( jV o'fntftnor 'or
Coreiraftr,; 'f f~vn Ms/mart et.i Ajiimei
SuC'ti i 4Jc?jt< Frofr 1.4JIZI
A- A»i«um»nt of Wrijjit dtndract let
C*rc:no(tP'Ciry	tt H,j6*r.l
t A»«um«iM #f *«.(~¦ #r tuOeau tci
Ca/waftfiift'* frem Sludial IB
Ew*nmmitl Aaimeli
C Cjir|^nun»n o! Ovtnt) Wftjfti of
I fiiim icr	CtreitevvniciTy
V	Aetirwnni
Ptfl • Xwtoew le Pubta ui *uor) fcatrs Ciwanu
I to
H O" u o< Scttnei TKJmstoty H.'fr
Rtpon en Ctvrrml Ccrzinaftit
III	Mtinot Cvidthnti
fV Ertluaucfi ef Irnifri Tumom
V	Twte/acinictBAC Mul: jtfi4iviionel
Aji'mei hocucyt
VI Monifivin Tsitrvitd Dcjf
Ytl M««*t L't- Tumon
Vl'l	tv lrnc* CeirfOTt
IX Quc/ttwt'** £»Ufliei« »!Kha
tin A Ciiddia* fat Cefdec^o L«k
J }f>industiot>
Thai u Oif fif»l rtvuion of iht irt
Imrnm Procid'J** tri Cu-diUi«i l«i
Httlih Hitk AiMiMrnti pi SittpKiti
Carcino| p^tmicoio© tnd*[«btuc«)
let cJTincf^n r/k turnaenc
Cu» documtn'- ut i nunSvr
aftntt »t thi ekti'tcuntttimet
vtc*nairtT) Ai ih^a ta«n»'Itdj« tad
•tMiiment oiibodolofY irt d«vtlop«d.
ih*« Cwdtlinti »i)l b« rt*i*«d
•rbmtvir tppropnn*
A tuauntrjr of tit rumni itatc of
k/icwltdfr Ln ihf fieid ofurctnoftntiu
uid t utiroitAi of brMd iDtnufic
pnnapiti of ctruno|te n»*
uirtiment »htd". wtt developed by
the Office of Science tnd Ttctaolofy
Po/ic> (OSTP ;«il (otim »» mponjnt
bitii for ihtit Ciudtlmei the forstt of
then Guideline* it tiQiltr lo thtt
propoted by Lh*	*«e*rei
Cokacil (KKC) of ihe Siuontl Acedetry
ef Sci«att» tn » book mtiUed Ritt
Aututntni us tAt Fttftrv! Gcvtmmtni.
ManagJU t^r Procttt (SIlClWl)
Thete Cutdeline* *r* io be uwd
•oih:n Lb* policy frtff.twork tlrctdy
prov.dtd b)- ipplittsJ» U>A iiatuiu
•r.d da aoi tlm tush policvti Tint
Cvudtlinei providi ttntril diivnou
for iBiljnaj uid o^tAisni ivitliili
4mu Ther do not utplj tht: an« k^e ef
dtit or aacih*f a prtfri;jji,u lot
ittulticrjr tcoon loconysi prombi'. cr
allow ib* u»e of a urwoff n
R«XU ,,0T deniion irtkir^ evolve*
two wiffipor.er.u ntk itMiimici and
mk mtni|einent Kiik turiimeni
define* the tdterM betlth cor.ir<|uencei
of txfotuft lo toxic ifenrr The ntk
utetinenu v\l! be umed cot
k&depeDdthtJy from untiderttion* of
Oie unaiqutncci of rcfultiory truen.
*i»k e*Jt*|tment oootbintt the nik
tiMtuacnc «nth (he dimnivti af
i*|Mlaiory leptlttiorv to|tth*; with
tcetotcortomie. ttcJuucti. poticicat and
other BonnderaOoni. la tttcK a decmon
•t to whtiher or how much lo control
blurt aspotur* to lbt miptned touc
Kiik atMiintst Ladudei one or sort
of lfe« foUowvti coapoaent* bAurd
it/tfluficstion doM-retporiM
aiM»iaenL txpotun Mtetiment and
ntk chtncitnuuon [NUC. 1S6JI
Htitrd idenuficatjon it » quelitabve
r(il titeiiitenL diilmi with the
procett of detemiiuai whither
txpotun to u t|int bat the pottnb^l lo
incMtie the uicidenc« of cgnetr For
purpotet of vhtM Guideline*, both
Btlipitnt tnd benipi rumor* • rr oted in
the evi!u»i>on of the earcinotenjc
btttrd TK* bittrd tdtnsriution
compontnl qutlittQvtly aniwtn tht
quetuon of iow tiit'y tn t|tnt u to be
a huntri urcmo|en
Traditionally qutnijitOve ntk
atietimem hti been vitd «• tn
tacJunvt ttfjo to dttenbe ali or pant of
dcie-mpomr iii(iimtnc.iKpotui«
uteiimrot and nik chtrietemation
Cutnutaiiv* ntk ihiwiuiiiua be a
uiiU (tntrtf irra in lomt
orruninncet' bui the more eiplicli
rtrm.-noJcio- developed by the SHC
u u*ut(ly prtfirred The doie-
mponie titettmem definn Hie
nlaiicnthip between dii dott ot *n
4|*m and iht pmbtbJjiy of indiicuoo of
a CArtinoftnc efTect Tbn component
eiuil y inttilt an turtpclttior. (rem lh*
generally Ki|h doiei tdminiittred to
ttpcrvatnttj arum tit or ajpoturei
acted in ep>demiolo|ic itudiet to the
*>;>glust le*di eipected fron huffun
contact with thr tff.n in (he
environment, it aJio meludei
contidertboni of (he vabdjry of ibeie
The txpoiure aiHttmeni idrntifi«i
popuitficni expoted lo the afenl.
detenbet their compotition and tin.
tnd prtttBrt tht typtt oapsnudfi
trequendei asd du/auoo* of tapoiurt
to tht «|«nL

Fadartl RogLaier I Vol SI No 1&S I Wtdnevlav Stpttmbe* 14 1006 / Koftcej
It r.ai chinctenieiion. the rvsulta of
the evpoture auetimem tod the doae-
iripi-.M esaesiaeot are oocvSmed to
mi .Titif quantitatively the carcinogenic
fin A« p*i of nit charecieruaooa. a
lusnio of the srrtngtha and
*»riu".ritti in Lbt hazard identification.
de»t iti;;.v< iifcitrinL iipout
itwunen: tod LSr ptclic health riafc
estimates err prtsen.ee. Mj>or
assumptions tciesLr.c ftcgiaecu. end
to t£e (kttni points*. estimate of Ua
uncertainties embodied to Ibe
aiirssoeai art also preaeaied.
dminguisinng clearly between lad
assumption. and acienct pobey.
The National Research Council (\RC.
1983) poioied out thai there an cuo)
questions encountered in the nak
asseiimni process thai art
unanswerable given cvurtni scientific
knowledge To bndge the uncertainty
that eitttt in these anas where tbtn la
do mfnr.fic consensus tnfereaeaj mull
be made lo ensort thai prog-cis
con-nun vn the aisesiaeat procaas
The OSTP (1«SJ nsffirwed this
poinion. and generally left to the
rt-f-Jaiory agencie* the )ob of
amculaung these inferences
Aocordinglv the Gutdehne* incorporate
ludgmentil ponnons (acieftc* policies]
baaed on evaluanon of the presently
ax ¦ liable Information and en the
regulatory evuion of the Agency The
Cuidelinei are oonaitteot with the
pnnople* developed by the OSTP
(10&i] elvhoug1" It mam instance* arc
neceit*':> more speaGc.
II Hazard IdeeLficoiian
A. ^ervww
The qualitative aiietsment or hazard
Identifies ncn part of rtai aiaeaiment
contain* a review of the relevant
biologies! and rtemical In/onnaUofl
beanng on wfcether or sot an sgmt may
poie t earonogr*ic hazard Since
chemical sg*ni» »«ldom occur in a pure
ante and aft often transformed In (he
bod) the w*new should include
available Information on contaminant*,
degradation products and metabolite*
Studtca art evaluated according to
aound biological and atatiancal
consideration! and prooedum Hieae
ha\e b«*n described m arvera)
publteanona (Interagency Regulatory
Lisison Group \STV OSTT 19&S Pete e*.
al 1000 Mantel 1H> Mantel tad
Haenste! iu» Interdisciplinary Panel
on Carcinoeemcitv 19M National
Ceaier for ToucologicaJ Raaaarch. 1M'
NationaJ To*icolog> Profram. 19M U S.
CPA. 1963a. lMJb 1963c. Haaema/t
1W41 Rfiulta and Qtmdutou
conea-nung the fcjroi den«ed frea
d.!!ertnt t>-pe» of m/ormauoo. whether
Ir^bcitlnf pewnve or ncfativ*
rviponaea. art irelded io|e'Jter into a
«ei|M-of-*vidence detcRTUi>a,J0& Tbe
atrenpih of the av.dence tupporun| a
potential human carcinoftmcity
ludfmen' •• developed In a »ei|ht-of.
endenct atratiflcation acheme
B Caseata of Hazard idenu/ieatjon
Hazard Jdrntificanon ahovtld include a
rrw* al the foUomng Information to
astent that tt ta available
1 Phyticol-Chemicel Prgptrtiat and
Kovln and Poturrj of Expeturw
Parameter* nlevant to oaimnoveMala.
tncJudinc phyncai atata. pkyatcai-
chetrucaTpropertiea. and tspoaun
paihwiyi in the enwenaest ahouid bo
de»cnbed where poaaibla
2. Savctur*-Activity Rshtionthipt
Thji aectioe ahouid au&manxe nlevant
atructuri^activiry corralatioaa that
auppon or arfut age mat the prediction
at potential eardoofeniary
) Mutbohe erd PhonroeekJMUe
Prcptnet Tbj aecooa ahouid
aurtL-nrtie relevant BauboUe
lA/orreaaoo. lafonzuoon euch aa
wteihrr the a|eoi ta durct-act>B| or
require! conversion to a reactive
earuoofenic (a g. an elecoophiltel
opeon. ffletaboltc paihwayi for audi
converaiona BacronolacuJar
tnteranona and (ate (a f. tranapori
atorage. and novnool aa well aa
apeoei differentet ahodd be diacuwed
and vocally evaJuatad.
Phartaaeokmenc prop«ttiei determine
(he biolcf cally e-e:S>e dow and tray
be reWvant to haiar^ identifuaUon and
other eempoaanu of nak aiaeaamenL
4	Tonoclonic Efrets Toxicalofic
affacta other ihi£ carnnoferuary (e-|-
auppreinoB of the una one ayatem.
oodoavaa dMrurbancei organ damage]
thai art rclevaat to tht evaluaQao of
cartmoyenjory ahouid be auamanced.
btancnona with other chemjcala or
a|enva and with Lfrtryle factor* ahouid
be diacuiaad Prechroruc and ctroaic
toudty evaJuabona ai weU ai other
(•tt rtauJti. nay yield infortubon on
Urget org 10 eifecu pathophyaiolofteal
rtactiona. and preneoplaiuc laaiona that
baar oo the evaluation of
caro&afvniciT) Doae-reaponae and
aaa-t>mporae analyiea of thaae
raacnona ma) alto be helpful
5	Short Ttm Teau Teiti lot point
sutaooaa. euaartul and amciunf
chromoaoma abemnona DNA damage/
repair and ui nm nnafomjooe
pro«ode aupponjva eridenoe of
caraoofemciiy and may fi*t
trJorraanon on potential carctnoftnle
(nediiruami A range of teata froon each
of lha above and potnta Selpi lo
charactanta aa agent a rvaponsa
Shor^-term ir nro and "» te»u
An can ft* inmcanor of incaMO" and
promotion imnry enay alic pronde
aupportive evidence for carcinoeeruciry
Lack of pot'.t:\e reauiti tr. ar.;n tern
teen for geneti: touci'y doe* not
provide a bam for diicoor.L^ ponjve
reauJn ui long terre amtr.a.' arjd ea
t Long Ttrm AmmolSivd.et C-te.-.a
for the technical adequacy of animal
carcmogeaicity atudjei havt beeo
pubtiahed [i| IS Food and Dru|
Admlmatrahon. 1BA1 lntera|tr.cy
KefuJatory Lianon Croup, irv
National Toxieolofy Prograo. IBM.
OSTP. 1M3 US EPA. t9Ua 1tt3b.
1943c. Faron et al. 19B&. Mantel 1000)
*ad abouJd be uaed to |ud|< the
accepubtlity of Individual arudiea.
TraniplaoeetaJ aad BuJti|eneraiiOQat
carcuiogeaeiu atudjet tc addjuoo to
more conventional long-term animal
atudjra. can yield uaeful Infomaitoo.
about the carcmo|«iucity of agenia.
It li recognuad that chemicaJ* that
Induce benign turn on tn^ucntly alee
Induce maJipant tuaon. and that
berogn nun on ohen pioyeaa to
oalifnint tun on (InttrditopUAary
Paaal os Carcu>Oferucj*y 1964). The
incidence of berths and malignaai
tumor* will be combined when
•ctan&fically defensible (OSTP. lftS
Principle •) For eumple the Aftacy
wtll lo geoeral conaiderthe
coobmauoo of beaj^o and mali^iant
tunon to be scientifically defanaibla
unleti the benign tuson arc sot
eonndfTd to have the potential to
prognu to the asaociaitd malig&aacir*
of the same hiatofcnic ongtrt 1/as
Increaacd tandaoce of beugn tuson la
observed ta the absence of malignant
turn or* in moat cues tbt evidence wUJ
be coaaidared as Lai lad e vide ace of
Tbe weight of evidence that ae ajent
la potentially carunogtmc for humans
Incrtases (1 ] with the increase In
number of uisue anea a/Tectad by tbt
agent (2J with the tncrtaae in number of
emmai apecie* (trtma seias. and
number of expanaaata and doaaa
showing a carcinogenic response t»
with the occuntnce of clear-cvt dose-
reiportae relationships aa weU as a high
level of atatisticaJ atgru/icancc of the
increased tumor incidence in treated
ca&partd to control groups (<1 when
there i* a doae-reiated shortening of ihe
time-to-tumor occurrcnca or tune to
death with ruroor and (}] whea there u
a doat-ftleted increase ta the proporuoa
of nunon that art malignant
Long term animal studies at oraear
the manmure talented doae level
(MTD) arc used to ensurt aa adequate
power for the daiaction of carnnogenic

Tadanl Ktgttttr I Vol J1 No 1ft5 / Wednesday Septerrbxr 24 1M6 I Notices
activity (NT? IBM lAfC 1M2)
Negative long Km emmal KudiM at
expoiu/t leveli above (he MTD may dot
be acceptable »f animat »unnv») it so
impaired thai the lenntivliy of the srudy
I* urufioantly rtducad below that of •
conventional chronic aeisal afi/dy ai
the MTD Tbe OSTP ;:#4£ Pnnwpie *J
bat it tied that.
Tbe eamitoftmc effecu of ajtnii My ba
Influenced bf log pAytislof >cal dtptain
(twek m	erjirv	radical
diirvplior of kormantl function eeiurauoe of
aetaboUc pathway* formation o( itmet tr
<6« onnary »iei aaiunooa of DKA repair
«nt> a hmciional low of tht fyai«a[ Iftdwaed
to tht »>odtl lytttma Tho&| *fi*iet
tndvcmi ihfM rtaportei ihould ba rvahiatad
lor itoii rvltxnc* 10 tht kwim rtaponae to
«n «f»ni and evtdtnea bos tuck a itudy.
wbaihtr potiuvt or M|iu«a. am bo
Poiiiirt trudjet ai abet the MTD
should be carefully renewed 10 enaurt
thit Lbi rttpontei art ooi due to factor*
which do not operate ai etpoaurt levela
b«lo» tht MTD Evidtnce indicating
thai brgh eipoiu.ii alter tureor
reiponaet by indirect mechanitmt that
say be unrelated 10 efTecla at lower
expoturti tbouJd be dealt with on an
tnd'v^d^al bant Ai noted by the OSTP
(10U) "NoraaJ metabolic activation of
carcinogeni may pon.bly alio be
altered and carcinogf mc potential
reduced ai a conaequeace (ofh^h-doie
letting) "
Carcmogt-.ic rttponiet v^dti
condition* of the e»pe.-uneit ihould b«
reviewed carefully at they relate to the
relevance of the evidence to human
CATCinc7ftr.it r.ika ie |. the occurrence
of bladder rvunort m the pretence of
bladder ttonei ar.d implantation alte
sartomai) Interpretation of arumal
afudiet it aided by the review of target
organ teucity aod other tftecu [e g.
changtt in the immune and eodoenne
»yiteai) thai say be noted in
prechromc or other lexicological etudiet.
Time and do«treleied cbangea m tht
Incidence of prtTieepiattic Wtiona nay
alec be heJpfid to interpreting aaumaJ
Ajenu that are ponove In lon| term
animtl txpenmenfj and alto ahow
evidence of promouni or cocarcmoteruc
activity u apecialized tetu thouid be
connderrd ai compltie C4rcino|ena
unJeaa there n evidence to the contrary
becaute it It at preteni dJTicuJi to
dettnune whtther an ajent u only a
promouni or cocartino|en;c Bgini
Aft nit that ahow pontivt rrtuJit In
apecial tetti for inmauon. promotion, or
cocarcirio|enin'y asid no ioduciry. the
pr.mary companion it tumor rvrpomc
10 doied	at ccaparcd «rth (hat
lb oenteaporary matched control
anunala Hutontil control data an
often valuable however aadeouldb*
«a«d aioni with concurrent control data
Ifi vbe evaluauoo of caruao|«ruc
rtfponre* (Htieoan e( aJ.. IBM! Tor 'ie
•valuabon of r%re ruaon even asaU
turner rttpontea may be aignlfisani
ecopand to biatoncal data The rrvftw
of tuaor data at aitea with high
•pontueoua background raquirta
•peciat oonaidcnuon (OSTP. )9U.
Principle 8) Forinjtane* a rtaponaa
that ta it^Turtcant with reaped to the
axpcnaiestal control p-oup may become
quettionable if the hmoncal control
data indicate that the exparuoerta)
control froup had an unutually low
background inodence INTP, 1M4]
for a number of rationt- there art
•ndelf djve^mj tnenoTic vtewi (OSTP.
IMS Ward at al irVa b TomtUi.
Tf77 Nutnuon Fojndabon i«3f about
the validity of tnoute liver ruaon ai an
indication of potential tareinoftruary m
buctant when tuch tumor* occur m
atraina with bijh apontaneom
bacik^round incidence and wfeen they
comtitute the only rumor raiponae to a*
agent Theie Cuidelinei take the
poticon that when the only tumor
mpocie it In the mouie liver and wht*.
other condition! for a cltti.fication of
"lu/Ticteni" evidence in animal itudiea
are met (e |. replicate itydiei.
malijnancy tee aection fV). the data
ahould be conndtti a* "aufTicient"
'endenca ofcarcinofenoiy Ilia
undeniood that thu citiaification could
be changed on a cate by-cate bane to
"Umited." If warranted when factor*
auch arthe followui| art obaerved an
Incnated t&odence of rumon only In
tbe fuiheii doie (roup and,'or onJy al
the end of the *tudy no aubatanLal
doie-related increase m tht proporuon
of tumor* that are nalipiani. tbe
octumnce of tumor* that art
ptdosunanUy b*n_g7i no doat-nlattd
fhonemni of the him to thtappearinct
pf tunor* nrgativt or ineoncJuaivr
niulia from a apectrum of ahon-tcrn
tent for muttjemc acuvity. the
occurrence of taceaa tuaor* only In a
*iA|le tex
Data from ali lon| tem arumal atu6ea
art to be eonaideitd in the evaluation of
carcinofeniciry A poaitive camnofenic
rtrponte Ln one ipeciei/ttrain/tea ta
poi (tnerally nefated by ntfauvt
rttulu in other apeuci/avtm/acK.
Replicate nt|ative atudiea that art
aaaenually idtnu&al to all other rttpvcu
to a positive trudy mty md.cate thai the
pot itive rttolis arc epunoua
Evidence for carcjnof r*:c acticn
ihould be bated on the obic**e'ici of
ttanititally tifrincart rur.a: reipcntet
In tpeeric ongana of tiatuea
Appropriate ataiittical analyttt aho^.'d
be performed on data from long-tern
studies to help determine wSether the
afTecti art (retmeni-rtlaiad or potato!/
due to chancr Theie ahould at leatt
include a aiaustical test for trend
Induding eppropntte correction for
dbfTertncas in eumval The weight to be
pven to the level of ttaiisucal
aifnificance (the p>vilut) and lo ether
available piece* of information it a
matter of overall scientific judfmeni A
atatittieally significant exceia of tumor*
of aU typet in tht a(frttata. tn the
abtenee of a itaiiitically ngnificant
increase of any individual tumor type,
ahould be regarded at minimal evidence
of carctnogttuc action urJeti ther* ar*
per*uasivt rtatont lo the conirary
T.Mumat Siudjtt tpide*aiologic
a'udiet provide unique information
about the rvtponte of humans who have
been exposed to auipect carc;no|tni
Deacnptive epidemiologic trudtea are
uaehJ in |eneraun| bypotheaet and
providirvg aupportmi daia but can
rarely be vied lo make a cautal
inference Analytical epidenuologic
sfrdiet of the cate-conirol or cohort
variety, on the other hand, art
artpcially utefj in aaieitin|niVi to
expotrd bunant
Cnteria for the adequacy of
epidemiologic atudiea art well
ftcofruied They include factors such at
the proper aelecoon and
bhsraciertution of exposed and consul
prsupi the adequacy of duration and
quahry of follow up the proper
Identification and characieruanon of
con/oundiai factor* and biaa. the
appropriate conaideration of latency
effect*, the valid atcenainmeni of the
cautea of morbidity and death, and the
ability to detect specific efTects Where
It can be calculaied the siatitucal
power to deted an appropriate outcome
ahould be included m the taeeiimert
The eu*ri|th of the epidemiologic
evidence for carainogenicity dependa.
among other thingi on the type of
analytit and on the magnitude and
epecj/icity of tbe rtaponae The weigSi
of evidence increaiet rapidly with the
euntber of adequate atudiei that th.ow
comparable rttulu on populationi
etpoied lo the aame agent under
different conditions
It ahould be recognittd that
epidemiologic arudiet are inherently
capable of detecting only comparatively
Lsrge mere a mi in the relative ntk of

Fadarat ftefUicr / Vol SI No 1*5 f Wtir.t*A*\ Septerbe' 34 1908 t Wo'irei
cancer N«r«cjTt moJr* frwt neb
iiuC:tt un-ji pno»a tht abance af
carti.-oeeme aeuon. howavet oaf«art
rttuJ'j iron a welldeujaed and well-
consisted fjifltrnjolopc trudy that
tor.iatnt utable eipciur* dlta ban aerve
to define upper Una of rvai. the* in
vteful if ajuna) evidence indicate! that
the a*«t li potaauaii; CAsznogrwciB
bum ana
C. W«i|h( of trtdtner
E*idm» of pcuibli careuiof eruety
la buBAAa cos aa pnaiani) Jreo two
ecurcei lon| lam aaiaal laau and
epidemjotofic mv(iU|ittDu Itaaulii
from tbtM itudiei are implemented
with available i&formabon from ah&rt-
Urs tttti. pbirmicotusatic atudjea.
comparative Btubolm atudiaa.
ainiciu/r-actmty reieboajhipa aad
other nloui tcurologit aiudiea. Tbi
queition of bow liiel) a.i af tat u to be
• hunts eartoojen ihould bt aaaoared
in the baaitwori of a wesghr-of-
evidence tudgitnt Judgraeala aboal the
wi^h! ortiadrtitt involve
contiderahoni of tht quality and
adequacy el tht data and iht kjridi tod
eor.mimc) orrtiponti Induced by >
euipect carcinofen. Tbere arc tlkrte
cnttof tlept to tharacttr.iinj lit weijbi
of evider.ee (at carcinogenicity in
fcursen* W Char* ntrfui ion ol the
evidencr fpsm huretn iftidiei and from
animal ttMditt Individual^ (!)
combination of tir chart cte~ia:ion» of
the»e two type» ol dm Into an
Indication of tht overall weight of
evidence for hus'.an ea-^inogemcity and
[31 r\ tluinon of ali tupporoni
Infoiraauon to delerarnw if she cveratt
i*eif|ht ol evidt sot thoyld be codified.
tPA htt developed a aytuifi fas
tirmfying the »et|hi of evidence I we
aection r»'l Thu clattiAuc.en la not
*ie#n( (o be tf plied nffidiy or
mechanics tty At ^anout pcirui it Am
¦ bo** difcwMicn. ZPA hat «npha«iud
tht n«d for an ovmll. batencad
Judfmeni of tfit toiaMrjr of tsallibl*
cvidmoc ParaculaHjr for wtlt-atudiad
•ubiianoai WtrliBc daU biM wfD
ht*t» umpUury 0\J> cannot bt
upiund by any cJainTitabon adhama
Threfwi tJi-e Itiurd l-denttftcaciofl
atcnofi ihovJd indudf a urratiha
au.T,rr«rir of tltt *Bmffb4 and
»(iL"n«i of 1h< rvi4«Jic* aa «r«U u
In eaieforu&on to tht LP A actena
The t?A cUwi&utwn	U. to
t«r,er«L u *4ipuaao ot
Ini*miowui Aftoct fat R««rareft em
Canctr (IAJ.C UB:; ftpproach Cor
clatdf>!t\| ficauoe ijiuto lot ifn
cXjractenxatda of (i« ovarmi! wc^ht oi
tn4anc* (or caruBoftaiari'»
bunuiL and ellwr aappcrtivt dtial
tncla£ti Cnjup A—Cari:i.no|tfiit to
Numanr Croup B Probably
Caraaof«u( lo Human# CrcupC—
PoMiSly Ca/aid(tnic to Huauva.
Croup D—Noi DunRablt at to Huunao
Carcaofrtioty and Croup E—
End*act of Noa-CarurottAiaty for
Hub* at
7>t fo'j«*ui4 sod;5:j(icnj of the
LUC appraatt kivi bwa midt lor
danJ>o| biunaa tod aaaaaJ rudiat.
For buoiin atuditc
(1)T^« obMPiauoD of a atibiucalljr
ilfmficam aaaoaiuao batwico u afent
aad )if(-(^taif roa| barup tuaori ut
buirini u indudtd id the evaJuabos of
mki to bustan*
Ul A "ao dju «v conaUTuiet
»"Lmi\ed" r^^diott of ca?t'.nof cruelty
f31 An Lnmiaed Incidence of
n*cpt»vrr.» thai occu hifh
aponiaoeom background incidence [ej.
ttcu»» Uver nuur» and rat pliiuury
rumon in unain itraliu] (etierallr
conatimut "(ufTioanr eodtnu ol
carcinogenicity, but may be cbanjed la
"limited' »hen warranted by the
apecirc infcrmaUoc available oo Ifae
H) A "no (fata available"
dainHcjvon bai beta added
(3! A "ao ev»dene« of carnrojefiteH)'*
daaaificatiob it alio added. Thit
operaijonal claatification would lAcludt
tub»i*r.cti for which there n no
tncrtiMd trade-nee of neapplaame la al
kit* twQ well-deilfned and well*
ccnduried ammal atwdiea of adeqoala
power and doe* Ut different ipeOea.
D Cuidanu foe Ooae Katpoaaa
TVe qialltatln avtderioa for
carcinofenaU* thodd tw ([laewaH for
purpotai offuidifi| tKa raapgrja
iiimmm TUa fuidaooa ahould ha
fven »n term* of Die apT*ap-*terie»*
and tunHanon* of »p*::fic ittd ee «t
•re 11 at phamacofc.'ei: muidtisoni
liai abould be fac'ortd int; LSe deir
rwpor.te a»aa*»(Bert The app^opr.ne
jnethod of eitrepolmon ths'jld be
factored In wher the erpenmerta^ foaie
of itpoiure dlfTen fros tbai occunvt|
A|aie of hwnao nik. T>ie rtak-
chararienutlon airp al»o tnctvdn an
Initrpretation of ihrta aeumiiei in
of tht biological itatiincal and
eepotun auumpoofti and anetrtaintiei
that have artaen dirov|ho«t the prwjee*
of ataeaafni rt»L
tt>« tlttmit of dctMiapwiaa
ajw*trnrfti art deaoibed tn aectJoti
fil X Ouldanca or fcunvtn tvpoiun
uaaaajnaftt t» pro«ld*
Fodanl Rtytm ' 5l ^ ^ / Wed.-ee Sepietr.be* U iW / Nqqqm
documen' (VS EPA. 19#£; bc»t»e*
aacuoo IDJB of theie Cuidelmei
tneJudci • bnef deacnpoon of the
epeeiflc type of expoiura information
that li uaeful for taruaogen nik
aiienineni Finally In taction 111 C oa
n*k charactcr.u&oa. there n a
deicrpr.on of Din.nr in wk :i ril
einmaiea ihculd be pretended ic ai io
be ffloit tn/oraanve
It ihould be empheuxed that
calculanon of quanniantc eiumatetof
cancer n»k doei not require that aa
ageni be carcutogenic tn hiunani 7%t
blebhood that an agtot it a huaaa
carcinogen it a function of the wtigfit of
evidence at thu bai been drienbed a
the hazard Identification aection of their
Ceidtlinei It ie eev»nheleii importaat
to prrtent qua/it.tativ» eittmaiei
appropnately qualified and auerptT*rd
In thote circumateneei tc whicfc then •
a reaionable poanbihry bated oo
kuman and anural data that 'Jit agent
U car*inofe*\jC tn husana
It abouJd be emphaiized in tv»«y
quantititjvt nak e* timet) on tha< the
reiulti art anaertam Unctia not* due
tc trpervnratal and epidemiologic
variability ai well ai uncertainty m tbe
expoiure aiuuoRi1 can be important
Tbiere are ma for oncertaintiet ui
extrapolating both (rots an.man to
kuacaju and from high to low doitt
There are important ipeciet diflt-rriMi
in uptake oeuboliam. and orjn
dninbulJCTc of caruaogem ai well u
ipeae* aad ttn-r djffereacei it U-T*'
me runept bib'y Huttin pcpJisoii
are variable wivi retpect to gea«:e
cooitimtioa. diet. occupational aid
borne eovvonment. acoviry pittem
and other cultural factor* (Lik
etfiiaate* ihould be prelected tote Ar
with lbe aaaooated baxard nmiso'
(•ection 0) CJ J io eaiurr tbat tben i»
an appreciation of the weight of
evidence (or carcinogenicity thit
tAderliee the quantitative nik **&®aie»
A Dote Reeponae Aaaeiitnent
. ejection of Dole At indicated tn
aection 0 0. guidance aeedi to be |>»«
by the ladmcuaU doing the qualiU'J**
atietiment [toucologiite patholog**
pbarmacologiiu etc.) to iboie doing ih*
quinuiaiivc aiieiiment ai to tbe
appropriate d«:a tc be uaec m «* dot*"
retponae iHewneaf Thu i# deief«tf>pd
by the quibry of the data iu redact*
to buman model of expoiurt aad ctbet
technical detaili
If available eiumatei bated oa
adequate human epidemiology
preferred over eitiaatei b»»'' 90
arumal data If adequate e*, _"e #*ta
ex.itt in a well-daaigned and
conducted negitive epidemiologic •'» '
It mi> be pomble to obtain an uppei
kotuwf iiibiu of«
Anjn«;-U**d aaaaatJ ifavauibie
*Jjc ahouid ba prwavd.
la tie	awe?"" Mimu
4au fro® • ***** *•«
nepooda *¦' bw bwnim toouid be
••4 J tAisrwaMB to (bit effect t&iau
^"htrm. (« a (:••• age*'- M"rai *0*^**
art a?aiUWc	avelva
tfnai »¦—-»	iniaa ud
¦irt at te>«raJ 6am ud By dilftrtfit
reuiet at evpoeu.*e tb# (;mO»X4
•pp-Ttach ie aelacog to data aeu ti
tied (I) TIm biaor ttadiou iau are
aep«m«d aecordoi to or|ia iita ud
tmor frpa. (21 /UJ Uolo^ciliy tad
itatJiuoaUy aocrpubli dan aeu are
prtMotad ()| fta r«agt of lbe nak
¦haai« i« preantad «ttb due regard
lo biolopcal raleraaa (panculariy is
the mm ai aniinii Mde»)ud
•ppropna urwti af rauie af upoeurt. [4)
|«ciuM it • poaaibu thai kuman
aeaaiuviry ta a* k^fc aa (be Boat
aeninite faapwmlag animal ipeoet. m
tbe itxwiri ti mdcoot to tbe cootrvy
6it biolopcAu) acce;uble data aet from
lonj tern »«' truiet tbo*vtg the
arM.iiviiy aheuid generally be
gr^ta tbe vaatrtt ea;Uiit agiut with
due ret&/c to b^'opcai tad iiaiaucaj
^*bro the capoaun rauti a tbe
ipeon tro* wlicb lbe dote-rciponie
Bfon%*l>ae »	dJfcn troa 'Je
fouie accvnog r anNvotmeniaJ
eipot-t*. IK* aru.de-vjotu uaed ie
Bat '4 lb» io-reuie eiripola »;n
«iui- U ca-e'wl') d«c-b«i All
aajjnpi.oru tbowd be prtMe:ij along
vi^i a d*acuMkan of uSa	^
theeto^poJbaB H"balew procedure
to idoptffrf is a f »en cam. h tyi be
OPn#itirn< vitb t/w evaug Betabobc
and pU.-matol ae-.t ifl-'aroatioB oo the
abaorpuac iCbeecy via
tbe gui a*d lk£«. (a/jri ar|is doaei aad
ltar«v« ta pU&nia.' trtaapon
(vtiatioa itm cuaplacaatal
two at aot etpuLcaatly
alrMied iua« a>u» at typta art
tt»rr>ri la the a*Ae itudy
ufftpoUtAa m*) be caaducted ut
aitn ar Tbaa* aalacuooa
anL be »ad» aa briegK*,' r>Udi To
abut e a toui nuaiu a^camaoaibc
n,L «u**Ja will «e» m mcrt i^.
aim ar r>p«e aiow>g «t
aie«aled Imaa aniM	Miimaij.
•ad Md Im e^trtaaUoaa n*
•o; r^TU, b ^
fTT*. » nal m^m ^ „
ler.ip tumor* aboud geceraliy be
eor.b.ned wiib BaaFvan1 tu.'Bort forr^i
atumatet unJeaa the oe.vfn tusot are
•ot conaidertd to ba*e the pcer.t.ai to
P'Ofreia to tba aiaocia-^d ma^p.anc«
of lbe aane Litogeuc or^n Tbe
cacmouuon of the beiujr 'ur.ori
however lo the total naa aaou wdJ review each
aiienmefit ai to the evidence on
carcioogenean mechamimi and other
biological or natiaucal evidence ibat
tndicatei the suitability of a pamcuiar
extrapolation model Coodneaa-of fit to
the tapenmtotal obaer\ationi ii not an
affective meant of diacrmnating among
modeli (OSTP. IMS) A rationale will be
iBduded to tuitify the uie of lbe choaea
model la the abaeaca of adequate
infcrsauon to the contrary the
Lfieanxed muluaiage procedure will be
employed Mhere appropriate the
retuht of uaiag vanoua eitrapolauon
modeli may be uaeful for companaon
with the Lsearixed muluatage
procedure M'bea longitudinal data on
tumor devalopment are available time-
to-rumor modeli may be uaed
Ii ahould be enphaaited that the
lifieanted mulimege procedure leadt to

43996	redmlRrpner I Vol SI. No 1W / Wednnday S«pierbtr 24 IMe 1 \c-cei
i pfiu*Wr upper to tb* nil tin it
eonnneni with torn* propoaed
macoaiuemi of c*/cir»oftneeii Sue)i an
(rnniiii bowteer doaa not ntceiaanly
five « ft«iini{ prediction of (he nak
TV trui value ol tha mk * unknown,
and n«r •« lo« aa uro The ranft oJ
n«( for BikiA|
"dui likely" or "batf attimatei of mk
withm tht ran^e of uncertainry defined
by (he upper ud lower tisui etumatet-
IT did ud pnocadurei-btcoioe
available the Agency wUl aJao provide
*bni Lilly" ot "bed ' etumnei of nak.
Tin will be moit feauble when buaan
data art available end when ttpoturti
art in the doae range of the data
le oanain UMi the line*rued
¦uJiiitift procedure can,sol 6« nt*d
with Lh« obiervW data u Tor tumpk,
when the da !i art nonmonotonic or
HtMtn oui n Ki|k dot*i In thete ciiu.
it ma> b« Decenary to make
adi'jfjntou to achieve low-dote
Whin phtntaco kinetic or meubobtB
diu in available or wben other
aubitmoal evidence oo the ai-chinnac
atpecu at ibf cartinofenetu proceta
axjtu ( low^doie citTapolaticn model
other thar the li/va~jed oulUeltge
procedure be considered fflort
appropnite on bioloficti fro and •
HVn t djCe**m mo ducju
the ntrure and weight of rt idence Lhat
ltd io the choioe Conuderable
unaertaiBty •'ill remain concemi&i
retpooae at low doiei the re Lore it
Don utei as upper-limn ntk ttomiia
uiiri| the Unearned multttUfe
procedure thould alia be prcaniad
J £«l jvo/eni tipeiu.T Ufuu Aj*ot\$
Sp&eiet U>»-do«f nak
dmvtd from laboratory atuffit! data
•urapolattd to hujnani »n complititnj
by a vintry of ficiort thai difTcr «mon|
•pcciei and potentially affect the
rtiToiK to carunofeo*. tnciudrd
unonf tfirit facton art difTartncti
brrwfro homanj and ixpcruBcmiJ tttt
vuaali with reap ret to Life ipuv body
•nt fentbc vanabtliry popuJauon
botnofenelry cxjutnce of concurrent
diitot pKannacokmeuc effect* tuti at
meuboliim and eicrtuoc p«iurna. a&d
the eipoiuri re|imen.
Tti utuiS approach for tnalunf
Iniertpeciti companion! Kai ba«r. lo
um iMndarlurd »ultnj lattora
Conn only employed itindirdutd
doitgt acalei include B| per kf body
•'•¦j1'1 prr di> jpoi m |j-.e djet or waitr.
K( per a* bad) eiirfeae ith
and n| p«r kt body wei|>it per bf« ijme
Is ibe abarnce of comperanve
tocicolofical phyaJolof C4l aetabolic.
lad phiroecokineac data for a fiven
Miptct ovciDOfen. A«enc> ukti
tie poiiuos ttiai tbe etsipoJiiion on
tfee batia of lurfica art* ji eoruidertd
ie be appropnaii becime certaia
phinuooioficil iff ecu common^ tcj'e
¦eooetiifgi >c wnfiee am IDednci. 1PTJ.
fnirtjch ti aJ. 19M PtnkiL 1U6)-
B bpoaitrv Amnmeat
In order lo obtain t quantitative
Mtueaii of ihe nak. the naulu of tht
doie-rttponae aiaeiament mutt bt
oombiMd wuh an Mtbnaia of th«
•	ipoaurti to which the popuJabona of
bitertat are likely to bt iub|tci While
the reader u referred to dte Cuidelinet
for Eaiimatint Expoaurti (IIi EPA.
1986) Tor iptcific deUili. II ii important
to convey an appreciation of the unpad
of the avtnfhi and wettaeitei of
•	ipoaure aiaeiiment on Ihe overall
carcet ntk aiitnntst ptoceu
At prtaeni there l* no tingle approach
lo tapoture aiteiimeni that n
appropriate for alJ caaei On a caae by-
mk bn-j apprepoair methodi art
•eleded to rcinh the data on hud and
the level of aophnucation nquurd Tbe
aiiLLtvpiiotu approiinatioru and
u&certamtiu need (o be clearly atatH
becauit m tome intiancei iheie
have a miior eflect oo the mk
In |«fie*al the naj-i lude daretior.
and frrquency oftxpoiure provide
fundamental information for eitimattrii
the concentration of the carcinofen to
which tht o^iruim t» eipoied. Theae
data are Rtnerned from momtonns
lnfotrnati0tt.m»dtl\J4 rt»ulu andiot
reeioned tetimaiei Anappropnaie
trtaorcot of tapoaurt ahould connder
the potential for tipoiurt via in|eition.
lohalanon. and denmaJ pentuanon from
raJevaAt aoorcei of txpoiuraa inctudiri
siuJtiple avenuei of miajit from tht
Mat aourcc
Special problemi ante wbtfl the
buman tipoaurt tiiuaoon of concern
tuoeiu tcpoiure reflment. a |. route
and do*u\| acheduJe that art
fubatannally different from thoae uatd
In the rtltvani animal atuditt UnJtu
tfcrn it av\de»oe io (St oon?tr> w •
particular caae the cumulative doae
noanrtd over a Ufnime ttprtaaed ««
averafe daily etpotura prorated ovtr a
lifetime Ii rtcorrunrnded at an
appropnate meaiure of tipotun lo a
cananofen. That n the aaaufftptioR la
cade lhat i doat of a tarona|ert
tecihrt tvar i abon period of em n
a^wvalent toa ccrrHpondm^ Icw-dati
aprtad over a life'.me Thji app-oach
bircomtt more p-sonT.f -t. at the
eipotorei m quei' on becore more
Interne but lea* (reqaer.1 ttpe:,a>.>
whrr !hart i» evidtr.ee sha' lie agent
lai ih?wn doir ri'e t/Te:u.
An aunr.pr ahould bi ir.a^e to aaaen
Ihe level of unceramry aaaoc ce: w.'Jj
Iba txpeturt Kiditsm: *>h.ch it io be
iiatd in a cancer nak aneaimert. Thit
aiaauri of uncinitri} ahouidbe
Included ui tht ntk chartcter.it boo
(»ec*jon ID C) tc order to provide tht
(ttciiioo-nakar with a elaar
ufiderttjandini of the unpad efthji
uncertainty oo any final quanntattvt
nak eiumtte Subpopulaiioni with
beifhtened auaceptibiiiiy (eithe* becauae
of tspotun or prtdiipcuitort, thoud
trbtn poaaibit. bt idtaufitd
C Rjak Chartctenxaaon
Rjtk characttnution it competed of
two parti Ont it a pretenatior. of the
eumencal tiumatet of ntk the other it
a framework to btlp iiidfe the
iifruficance of the ntk Riak
characterjation mctudii the tapoaurt
aaaeiimtni and doie-reapor.ie
atteitmeot. then are uted it the
tiiLtr.aaon of caronogemc naL If may
alio csnim of a uAtt-nik aatimatt
wbich can bt ccmbintd tlatwhtrt with
Ibe tapoeurt aaietireent for the
purpoiei of eiumatatf cancer mk
Haia.*d identiTicatJOfl tod doae-
reiponte atiettment are covered in
aecnoni 13 and U1 A. and a deuJed
ducuttion of ttpoaure aueitme
T»dtnJ Rtflite/ / Vol 81 No 1*5 I Wtd.nndi>. S«pt«rr.bfr 24 1W / No'jcei	13999
produced per year to tbt upoeed
population or both.
lmip»c'jvr of the option* choien. tit*
defret of prvcmon and tecitftey in the
numerical nil estimate* mrrtnily do
not permit nor* than om ugniAcant
figure to be preienied
i. CorzuTrnt Expotjrt In
characteniLTi the nit due to ooncumnl
•ipoiurt lo *f vet«rcuio(t.-.i the
mil irt combined on the ban of
addmvir> unlen there it epaafie
Information to the contrary Interaction!
of cocareinog tni promoter and
Initiator* with known ctrcinofena
ahouJd 6* connderad on • caie-by-oaie
S Summary of Rtti Charocttmoijon.
Whichevtr method of praaenia&on n
choien ii ii cnucil thai tht nuswncit
eitimam not be allowed lo itand alone,
aeparaied from the \anoui amiptioni
and unctnuniifi upon which they arc
bated. The nik charade-ration ahouJd
contain a ducuiuor. and interpretation
of the numerical eit.Tiatei that aflordi
the nik mmager aome mught into the
deg*ee to which the quantitative
emmitei art likely to refleci lh« true
mif-iioidt of human nik. which
generally cannot b« known with the
degree of quantitative accuracy
reflected in Lht numerical eatiJT-.etei Tlie
final nik eitimaie will be fentrally
reurdedtoc- »gnific*Tii figure and
will be coupi-. -iihlhtD>^
climfication of the que^aLve we.gVt of
evidence For example a lifetime
individual n»k of 2 * 10'* reiultmj from
expoiure to a "probable human
carcinogen (Croup B2| ihould be
deitg-iitedai 2x10"* [Bii Thu
brackried deiifniuon of the qualitanve
weight of evidence ihould be included
with all numerical r.ii ett.ir.atei |i e .
unit nikt which are naki at a ipecified
ccncerL-ation or concentration!
correipondmg to a given nak) Agency
ataiemeru luftrai Fad era! lejUtar
noncei bneflngi andaciion
memoranda fwquemly mdudt
numencal eitimatei of carcinogenic nik
It ii recommended that whenever theie
rumenci) eitimatei are uied the
qualitative weighi-of evidence
cliiiiHcuion ahould alio be included.
The lection on nik characterization
ahouJd tummanze the hazard
identification doae-rcaponie
aiienment expoiurt aneiimenl and
the public health nik emmatei Maior
aiiurrrptioni acientific rudfrnenta and
to the e**eni potuble eitimatei of the
uncenainile* embodied In the
aneiimenl an prriemed
/V CPA C'aii:ricfj9r SytUmfor
Cciefor.vAg Ha/|A/ of E*idta:t for
Carcinogenic;(/ /Vom Human aj\d
AnimalStuditt (Adapted From UACj
A Aneiimenl of Weifh; of Evidence
foe Caxi.ie|tmcity Frcrr StieLei in
Evidence of carmnogerjctty fro IB
human arudiea cocti frca three saw
1 Caie f»poru of individual ctsctt
pi'jerti wbo wen eipoaad to Iha
2. Deacnpiive cpirfemiolofte itttdjaa la
which the incidence of c&ncer ui bumaa
popuJiuoni wai found to vuy tn ipact
or tunc with tipoiure lo the agentlij
S Anatytica! epidemiologic (caaa-
ccntrol and tohon) injdiei ta which
tsdjvidual eipoiuft lo the agent(»] wai
found to be aiiocmed with an
increaaed nak of canctr
TT)*ve c.:m nuii be met befort a
camal aitociatjon can ba tnfirrtd
ber»eer eipoiurt and c^nccr in
1	There n no identTied bm that
coufd explain the aiaociaiton
2	The pombility of corJounding baa
been cor.ndertd and ruled out aa
ccplam.nt tht aiiociauon
S The laiooitjon n uahkel) to b«
due lo chance
In gerie*il although a unfit atudy
may be indicative of a cauie-efTeci
relnerk1- p confidence in mfernng t
ca.ii' tuocn'on n mceaied when
ae^e'al mdependen' t'udiei are
concordant in ihowirg the aiaociation.
when tht aiiociauon n ivong when
V^crc it a dote-retponie re'atiomhip. or
when a reduction m axpoaurt ta
followed by a reduction in the incidence
of cancer
Tht weight of evtdenca for
eartinoger.icit) 1 from irvditi in humane
u damfied aa
1 Sufficient evidence of
carcinogenicity which ind.eatei that
there n a cauaal relationihip between
tht agent and human cancer
£ L.mited evidence of tarcinoftniOTy.
which indicatea that a cauaal
Interpretation u o*dibJe but that
alternative eapUnationi auchai
chance biaa or confaundinj could not
adequete'y be deluded
1 Inadequate evidence, which
Indicate) thai one of two eonditioni
prevailed (a) there were few pertinent
data or (b) the available atudiei while
ahowing evidence of aiiociauon. did not
exclude chaace biai or corJoun&fti
1 tv nmm of Wal\> inotw
•uocj«<«£ w>ui iif#	hrtif	*
ia iht
and therefore a cauaal tntc*pre:a:.on u
¦« ovdjble
4 So data which indicatea that data
art not available
I Ko evidence which "Jtd.:atei Lk.ai
do aiiouauon wai lojnd be*weer.
expoiu/r and an inenaied rik of
caocer tn weil-duifned and wt!!-
conduced independent analytical
tpidtxjolop: atwdiei
B Aaaeaement ol Weight of Evidence lor
Carcinogenicity From Studjee m
Lxpenautal Ammala
Theie aaaeaimenti an daenfied into
five froupa
1 Sufficient evidence1 of
carctnogemnty which indicate! that
there ta an ir.creaaed incidence of
malipant nimon or eonbmed
malignant and benign tumora • (a) in
multiple ipeciei or atratna or [b| in
Bulnple experunenta (a g. with different
rcuiri of admimatrabon or uim|
difTerrnt dote leveli) or td to an
unuiual degrre in a aingie experunent
with regard to high incidtcce unuiual
lite or type of tumor, or earl) age at
Additional evidence may be provided
by data on doie-reipotiat aflectt. a*
well ai mTormanon from ah on-term
lain or on cfcenucil atnictun
1 Limned evidence of carctnofenlcity
which miane that the data lu^rx a
carcinogenic effeci but arc limited
becaute (aj the arudiea involve a atn^le
ipectri atrain or eipetmen: and do not
met: cnitni for aufTicict evidence (aee
aection I\' 6 1 c) (b) the expermenn
are rtitncted by inadequate doaage
leveli inadequate duration of erpotun
to the agent inadequate penod of
folio"-up poor aurvival too few
animali or inadequate reporting or (c]
an mcreaie U) tbt incidence of bervifn
tuaon only .
9 Inidequate evtd' e which
Indicatti that becauae of maior
qua! tative or quantitative limitationa.
the ifudtea cannot be tmarpratad aa
ahowtrtj either the prcaenca or abaence
of a carcinogenic effect
4 No data which indicaiea that data
are sot available
I No evidence which mdieaiea that
there u no mcreaaed incidence of
seoptaima in at Icaat two wtU-dengned
1 A/I Bto«aM4 ooinw* «' wflUiiN Ifc*' Mcwr
*"il> hijh tpoitianMwi	mciMAGf 1*4
• 9VM iivpr	'*»«'•'>	It
Of MfUWftn'CHI	t*	10
"liwmrd	UN •V*H ba pombwt
\ht	at w cwti^im m fc*<«
IN ^crrii.ji ie	* uaa itim'rt
«f iha mm	•r^,r'

FodartJ lojiAftr I Vol 51. No 1>5 / Wedietdav Stptfnber 24 1986 I Noncei
¦rid wtU-cooducird aruaal etudite Lfi
d/Ttrtnt ipvciM
The cJiitifi&auoaa "auiEcitnl
evidence ard ' limied evidanca" rofer
on'.) to the weigh: of the upmsuul
e»ide-ce the' thtM agenta in
ctrcmof emc anc so< le the potency aI
their caru>9f«r.j: ecuoa
C Catefonianon of Ovenl height of
Evidence for Hujr.in Carcinogenicity
Tb» overt 1! echeme for catrtoniation
of the weight of evidence of
carcinogenicity of • chemical for
hujearu utei • iL-te ttepprocati. (J)
The weight of evidence m human
etudiei or aniaaJ Kwdjet a lusatnztd
(2) the** knei of loformauoa in
combined ® yield • ttaur.n
amgnrent to • category (ate Table H
and (1) ell relevant aupporuve
information it evaluated to ee* if the
detifnauoo of the ovaraii we^b: of
evideoce Midi io be nodJied. Relevant
faciori to be included along with the
rumor tnforma'ion from human and
an-.ir.al itudtei include itructvtfvacvwty
reletionthipt ahon-term teit findingi.
reiulu of appropriate phyaiological
biochemical and toucological
obatrsationi and comparative
Bietaboliim and pharaieolunttic
ifudiea Tin nature of three flndugr
ma; cauae one to adiuat the ovirail
categonxaboo of the weight of evidenca.
TaKlE 1.-JLLUSnutrv£ CanoonilATiON Of EviOCMCC Bascd o« Ammai.
amd Human Data >
Lrwad	__
No oata	
No i
• 1
• 1
I 0
'	¦ ¦ u trt irwi- «e i® kanM ft/oowa 'Vi »*> to  jr-jxr. rvxx cm mm m c *>•—»-» < ra onoiw c r«
Mil	a >'»» u <»ra it at «oe < «/s «
wux • pr i ».».¦-» ¦«. imf rc	iw^xrv me oo*«>w>« ««i»v ro
team **<• uwi 0 Nm Vev-^j s+sm r	7 r« ^nl ayo.-r
d fm wyi 7 » era
The ijenci are categotned into five
froup4 u foilowi.
Croup A—Hunan Carcinogen
T>ui poup i» ut*d onJy whea there It
eufTiclent evident* fritr ep dftvolofic
etudiei io tuppor i cajia! tttociabon
between eipoture to the agenu and
Croup B—Pnbab!t Human Carcinogen
Tin group Indudei agenu for which
the weight of evidence of humid
carcinogenicity bated on epidemiologic
etuditi u "Uruied and alto include!
agtnti for whjch the weight of evidence
of carcioogenicjty b«»ed on aruaal
etudiei it tulTicim'' The group t»
djuded into two tubf&upi L'tuell)
Ctvjp Hi it rrterved tot agtou for
whic^ there n tunned evtdeno* of
caronofeniciry from epidemiolofie
atvdiei It ii miontble for practical
purpoiei to rtgt'd an ageoi for wtuch
there it tuftkieol evidence of
carcLBOfeojcjty is arunalt aa tl It
prttenta! a carrinsgeruc nik to husaAa.
Therefore agenu for wbch there ia
'' tufTicient" evidence boa aaimaJ
atudjet and for which then u
"toadequaie evidence" or "no data"
froo epidemjologjc ttudiea would
uauali) be cjirgonud aflder Croup B2.
Croup C—Pottiblt Human Carcinogen
Thit group ia uaed for a genu with
Lmiiod mdeAca of eAaiaofrnjcity ia
animate in he abaenot of humtfl data It
incJudet a wide variety of evidenot. *4
(a) a malignant tumor rwpoaae is a
tingle w*U
Tbjt poup u gene'iUy u««d for ageou
witk. tfude^baie hj£Ar ari ar.r.ai
f\id«cc« of u.-^3|(i: -> or far whic£
no data are avaua^ie
Croup £—£ti the
CrvvvriMfittl Preteciion A|«-.ey (of the
•ttrvtmeot of cerwiofenic nm | Nell.
Cancer irsL U.1U7MMI
K-S. HoeL D C. Unfit? OLfeta.
L Fuad»m«itl u/uofenic
pnotuti iad Ikair impbcjoaiw for low
doM n»i ummiidl Caacar lu 1U0~3-
Drdnek ILL ltn Arumtl Scale Up J
narreecok:ee'. Biophtro K3V4C1
FetwaV|.C«ee HC Ceietmer t Nio
R_ KC**. C. AltAoff | Arnold 01
HumeotntL H CabrtL | R/. DtUt Porta.
C Ito N Km»«rlt C. Krott R. Mohr
U KeptlLoir N.P. Odiihimt S- N|<
K P SclviMi. T Sif jiiefT 0. S«|tr |.
Toaetn L Uehieki KLandVoukV ltn.
Banc ivqutrereanu lor lon| i*ts iittyt for
cerunofvurity In Long term ind ition
ttrm is««nin| m«ri lor earemofeni a
crucit eppraiMl. IAXC Wonofrtphi
feppieaent 1. Lyoft. Frvioe Iniemationil
Aftney for Iimiret ob Center pp n-Al
FrfiTiCi. E.|-C«iin EA R«:i D P.
Sc\r>di LK. and Skipper KLL 1«M
Quantitinve companion of iotici>> of
antitanoer egetiu in nsuu t«t fcimtitt
dog otor.key end Btrt Canoer Chemother
Rrp WTI»-2M
Kiiman |K 1M4 Siautiical taiuee ia the
deiigi taalyiii and lAierprtuuM of
•rufttl ctrsjio|»oicjt) eiwditb tnvu^n
Health Pe'ipeci SiUMK
Hurman | K. Hu!T I and Boorain C A.
tM« Ute ofhmoncal eofol dtia in
carcinogenieiiv e'wd.e* in ledenit TomcoI
PeUiol U.I2»-m
Iriera^ency Xrguieiary Utitor Ceo up IUU.C)
ir*t Scienufic bam for iOenvJ.c«uon of
poi*nii*l cjrcinsfrni and emmnon of
mki | Sill Cancer Inn O 24V-U*
Iniei^ inplmin Panel on C
ftdaril Reyittr I Vol 51 No 1&5 / Wednesday Stpter.ber U IBM / Vo'.icei	J4001
C»tiuinon of IS* C*tin«to«iwyt NCTR Biometry
Repon liwm Available torn National
Center for Toueeloficil RtMtrth
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TKji ;*cnon lummarltei the major
Uiuei railed dunni both the public
comment period on the Propoied
Cuidelmti for Cvciro|cn Rjik
Aneiiment pubinhed on November 23.
19M (49 FR 4U94) and alto dunni (be
April 12-23 1M3 meeurvg of the
Carcinogen Rj»k Aneiiment Cwdeltnei
Panel of the Scieoe« Advisory Board
lr order to rtipond to theie Itioei the
Ajency modified tbe propoied
fuide'.inei in two itigei First charvjei
reiult.ng from conndertuon of the
public commcnti were made in • draft
•cnt to the SAfi rrsiew panel pnor to
their ApnJ meeung Secondly the
^iidclinea were funher Bodjfied m
reiponie to the panel s
The Agency received 62 acti of
oommentj dunng the public colament
penod including 24 fnm corporation! •
from profesitonal or trade aiiooauoai.
tnd 4 from acadesuc iniututioni In
general the comments were favorable.
The commentora welcomed the update
of the 1271 guidelines a/td felt that the
proposed ruidelisfs of IMS reflected
some of the progmi that has occurred
in understanding the mechaiuama of
earcjtogenesis Many comatenton.
however fall that addiuoul changes
were wananied
The SAB concluded thai the
guidelines art "reasonably complete la
their conceprual framework and art
eound in their overall Interpretation of
the scientific Issues" (Report by the SAJB
C4rciB9|emcity Guidelines Review
Creup |une IB IMS) The SAB
ruu*'«d various editorial changes and
raised sone uiuei regarding the content
of the proposed guidel'nes which are
discussed belcw Bated on these
recommendations the Agency has
Bodified the draft guidelines
II Office ef Scitnce and Ttz^ncicgi
Policy Rtpon or Chemical Cax:.~>ogert
Mary commentora requested that the
final guidelines not b« issued until after
publication of the rtpon of the Office of
Technology and Scienu Policy (OSTP)
on chemical carcinogens They funher
rtqueeird that thu rtpon bt
incorporated into the final Guidelines
for Carcinogen Rjsk Ameament.
The final OSTP rtpon was published
in IMS (SO F* 1007-2) In ita
deliberations, the Agency reviewed the
Anal OSTP rtpon and fetla thai the
Agency's guidelines art consistent with
the principles estsblnhed by the OSTP
In Ita review, the SAB afrttd that the
Agency quidelines are genertlly
consilient with the OSTP rtpon To
tmphasiu this coniutency the OSTP
principles have been incorporated into
the guidelines when controversial issues
art discuMed.
Ul hftrtnet Guidthnn
Many oommeatort felt that the
proposed guidelines did not provide a
sufficient diiUnction betweto scientific
fact and policy decisions Other* fell
that EPA ahould not attempt to propose
firm guidelines in the absence of
acienufic consensus T>ie SAB rtpon
alio indicated the need to "diitingvub
rtcommendaiioni based oo scientific
evidence from those based oo ecienoe
policy decisions "
Hie Agency ifrtes with the
recommendation that policy.
|udgmenial or inferential decisions
should be dearly identified In us
revision of the proposed guidelines the
Agency has^ included phrssei (e g.' the
Agency takes the position thai' | to more
clearly distinguish policy decisions
The Ajeney also recognizes the need
to establish procedures for action on
Imponant isiuti in the ebaence of
complete acientific knowledge or
consensus This need wai
acknowledged in both the National
Academy of Sciences book entitled Rj$k
Management m the Federal
Government Manoginq tfie Procett and
the OSTP repon on chemiul
carcinogens Aj the NAS repon states.
"Risk assessment is an analytic process
thst is firmly based on scientific
considerations but it also requires
ludfments to be msde when the
available informstion n incomplete
Theie ludgmenti inevitably draw on
both scientific and policy
conaiderations "

P«W«J Rffltitr ! Vol Si. No 185 / Wed-tidiy Se?te~bt' 2* 19K / Noncn
TW wdgmeno of the Aftrtcy have
been baaec on ounot available
aoeniific inform a t> on and as tbe
con-bintd tvpenetice of Agency txprru.
Theie luejnenu end lie reauluni
guidance rtiy on inference. howrver.
the poi tioni taken in theft inference
fuidelinM if* fe'i to be wttonible ltd
acientificall) de'enub e Whue al! of ttie
guidance* 10 lone diyt beted on
inference the guideline* M*' eMempird
lo diiiinfu ih thoae imuci that
depended more on Jwdfrnent In thet*
ceiee the Agency hai Hated I portion
bui hai alto ntained flexibility to
accommodate new data.or apecific
circumnancei thai demoniirtte that the
propoied petition ii inaccurate Tfce
Agency ncofnae* thai eatntific
opinion will be divided on lb«»» him
Knowledge about ceronofena and
earcmogenene n profreiung at a np adi«nce» m the Ctld.
A' EioljaLtor of Benig n Tumon
Several commentort diacuMed the
appropneie inie"pr*"bon ofan
tncT*eaed incidence of benip lumon
alone or wV.h an incrtaicd incidencj of
malignant rum on ai pan of the
•valuation of the carcinogenicity of en
agent Some corr.me-H wet i.ppo"*i»e
of the poimon in the propoied
guideline* 11 wider oenem
arcumtaneei the incidence of benign
and malignant mm on woald be
combined and an mcnated incidence
of benign rumor* alone would be
considered an indication albeit limited
of carcinogenic potential Other
comnerwori naed oonormi about the
criteria that would be teed to decide
whicJi tumor* ibould be corrbined Only
a few aommenton (eli that braijn
turn on ahoulj ne%er be oonndefvd is
evaluating uraoofcnK poneuaL
T\< Ajrncy believea that corrvnt
information auppona the uae ofberugn
tumor* The gudtltflu have barn
modified to incorporate the language of
the OS TP repon. i«. benign tumor* will
be combined wiih malignant tumon
when acienijfic»lly drfew.ble Thi»
ponlion aUo«»* fleubilnj ia evelueti&f
the data bate fo» wet agcoL the
fviidehnei bi«e a bo been modified to
indicate thai, wfceona/ bersjn and
Daligoaet tusori have bees combined,
and the afteoi r* oonaidered a c&ndidaie
for quantitative nil aimpolabon. tha
contribution of becufB rjt&on to tha
aanoauon of rut w\If be cdiaatad
V' Tn/tipfoct*fo/ onif
My/uftnenuo-tol Arumel S/oa«a>#
Aj one of ita two propoaali for
addition! to the futdelinet the SAB
fecomnended a ducuinon of
tranaplacental md m Ji>ge.icrational
animal bioanaji for carcinogenicity
The Agency a^eea thai auct data,
wbeo available tao provide vaehjl
informatior is the evaJuJbon of •
cfcefucti a potential carciftofvniclry and
hai atared ihia m the Knaf fuideime*.
The Ajtency haa alao reviaed the
fuidelmei to indicate that auch itudies
may provide additional in/ormalioc od
the metabolic tad pharmacokuabc
properuee of the cheniul More
guidance oo the ipetibc uae of the«e
atudiee wUJ be aonaidervd ia hitw*
rrvniioni of theae fj^delina*.
\7 Matt/nun Tolerated Dote
TV propoied Kviidelmet daouaaed tha
ImpUcaiioni of uung a siaximim
tolerated doae (MTD) in bioaaaayi for
cttwotenieii) Man) comwfnton
requeued that D*A define MTO 7>ie
tone of the cotvmenta au^ated that the
commenion were ooncemed about tfie
uaee and loterpretaiioni of high-doee
The Agene) weofnue* that
controvert) ev/rtntly eumundi theie
taiuet T>e appropriate test from the
OSTPrtpon hai been incorporated »r:a
the final fuidelinei wS?ch	tha'
the conieqjtncei of higt'.-doie teiiir^ t>e
e\a!uitrd on a cate by cau baiii
VII Atoui* L/*er Tumon
A large number of oommentora
aiprttied opioiona abogt the
* aneiiment of bioaaeata in which the
only increaie in tumor incidence wai
liver tumor* in the mouae Mary felt thai
tnoute b\e'r tumon were afTorded loo
much credence eipecially pven e*Jann|
trforrnition that tndicatea that they
might ana* by a different mechannm.
e |. tinue damege followed by
regeneration. Other* felt diet fnouie
liver tumoni were but one caie of a high
background modenee of one panmlar
t>pe of rumor and thai all auch ftimort
i.SouJd be treated in the mm faabioa
The Agency ttaa reviewed theee
commenta and the OSTT pnndple
regardmi Ihn iitu* "Hii OSTP report
doea not reach conduaiona ai to the
treaitsmt of rumori with a bt|h
fpoataMOut beatground rata but
atatet aa ia now included in tha te*t of
the fuidtlinn that theaa data require
apeoal oonndereoon. AJthovfti
queiiiona have been relaed rrftrdlrvg
the validity or mouae itver tumori tn
rn«raL the Agency feeli that b«o«m
w tureort caaaoi be Ifnorvd aa an
indicator of carr.aogeruc:t> Thua the
poiirjc ia the propoied fi.deiinei bai
not been ohaifed an increaaed
Incidenoe of ool> aouae liver tumon
w\ll be regA/tied ai "auK.cieit evidencr
of carc.noger. c •> if a.'l othf c"te-a
eg replication and malig"airy i«e met
with the urden:and:ng tha: thia
daaiirication could be changed to
"limited" J warranted. The fac:on that
may cauae Uui rr-evaluauon art
indicated ia the guideUae*
V/IJ Weifhiht-of-
evidenoe dainficaOon
The Agency hai added a diicutnoa to
Part A. mcuoh rv C dealing with the
eharacteruaUon of overall evidence for
homan carcinogenicity Tbn ducuu.on
clanfiea LP A i uae of aupporuvt
in form « b oo to adiuat. u warar.ted. the
deei^niLon that would hav e been made
aolely en the bana of human and lor|-
term animal anidiea
I "Hie Agency epeei wth the SAB
and thoae conunenion who felt that a
aimple daiaification of the weight of
etideoc*. a g. a e^njie letter or even a
deacnptjve title ia mad equate to
describe fully the weight of evidence for
each individual chemical The final
fuidelme* propote that a paragraph
tummannng the data ahould
accompany the numerical eatjmete and
weigM<«f-«vldence daitiftcataon
whenever poaaibla
i Several oommentora obiected to the
deacnpiiva bile E {No Evidcncr of
Carcinogenicity (or Hutnani) became
the) felt the title would be confuting to
people inexpenenced with the
clamf cation lyitem T>te title for Croup
L So Evidence of Caranogemcit) for
Humana wai thought by theae
commmion to tuaut the abaence of
data Thii group however ia intended
lo be ntMtvtd for ajenu for which there
eura credible data demonatnnng that
the agem ia not carunogrruc
&a»«d on theei eemmenta aad further
dltcvuion. 0*e Agency bat etiaafed the

f»4cr«l	i Vd! 51 N'o 1i! / Wedntidiy Sfpit-.br 24 1966 / Saticn	3430.3
Lilr el Crojj £ is Ewdenct ofScB
Cartmoge nicitj for Humana "
4 S*»trtJ commenrora left (hit ;ht
(Hit for Croup C Pomblt Human
Carcinogen. wti not lufKcienily
di»nncti*f from Croup B Prohibit
Human Carcinogen Other conrt-ori
f«li that thote egtnti that
qualified for Croup C would lau
sufficient data for auch t label
The Ageney recognixei that Croup C
coven a range or chemica't and hat
considered whether to mbdividt Croup
C Tht conwniui of the Agtney 1
Carcinogen Rjik Aimsmeni
Committee however ta that the current
froupt which an bated on the lA&C
categories. are a reasonable
stratification and ahould be retained at
pretent The itructure of the groupi will
be reconsidered when the guidtunti art
reviewed in the future Th< Agency alw
feeli thai (he detcnptive uUt n
originally lelected tie it convert (he
mtsning of the cJasnficatior witha the
ccntrxt o( EPA 1 pan and current
I Some conunentors indicated a
concern about tht duuncuon between
Pi and Bj on the bun of epidemiologic
evidence only "TTm» i«ut has been
under 6»rvjn*on in the Agtney and miy
be reviied m future veniotu of the
• Comments were alto received about
the potubility of keeping the poupi for
amm*7 and hur. in dan teparaie
Kiihout retching t combined
daanrication. The Ageney feel* thai a
combined elatuficaiion ta useful thui
the combined claudication wit
retained in the final guidelinei
The SAB luggtued Lhat * table be
added to Part A aecuon IV 10 indicate
the manner lp which human and ani/rtl
din wouJd be combined to obtain an
©*e*t!l weight-ol-tsidence category The
Agency retlnet iht' a table that would
pretrm all perrauituoni of potantitlly
available data would be complt* and
jointly impomblt 10 oonaimct 11 act
rumeroui aJMblnaliotia of ancillary
dti* If | genetic touctiy.
pharflitcokintiicij could hi «std to
raite or lower the weighr« P«'»"c ,Muei
wet ditcuittd bf iht Agency and have
rttulted ui ood Jiiationt of iht
guideline 1
1 The maior cntician wat the
perception that EPA would uic only one
method for tha tti/apolation of
carcinogenic nak and would tharefot*.
obtain one tatimalt of nik Even
oonaenion who concur with the
procedure uauall) folio*ed by CPA felt
that aovie indication of the uncertainty
of the nak ettimai* thould be included
with the nik animate
7>ie Agency feelt that the propoted
guideline! were not intended lo auggett
that CPA would perform flviantitntvt
nik eturaatet in a rote or mechanical
ftihion. Aa mdicaitd by the OSTP
irport and partph'ated in the propoaad
gu dtlinet no atnj't nathcmatiui
procedure hai been determined to be
tht icon appropriate method for nik
extrapolation The final guidthnea quale
nther than panphrue the OSTP
principle The gurdelinei have been
revned 10 ilmi tht irportance of
cornidenaj all available data in the nak
• tieumtnt and n£» ttate "The Agencj
will renew tach iiitnmcnt ai to the
evidence on carcinogenic tnechammi
and other biolog'dl or itit.itical
evidence Ihit ind'CHet the tuitab>lity sT
1 parucular extrapslt'ion awdfl" Two
lituti an enphatiied Fini. the ten
now indicatu the potential for
phirmacokmetic tofornation to
contribute 10 the anettmant of
'carcinogenic fltk. Second the fmaJ
gutdHinet aiate that tima.t»>rwrroT nak
exnpolttjoip modeli tnt> be uted when
longitudinal data on tumor de*elop*itnt
are avaJable.
L A number of commenton noted that
the proposed gMidHimi did aot indicate
how tht uccnatnciei of naJi
characJeruation wouJd be preierrttd
The Agency hat rinNd the pnrpoee-d
gvrdelmei 10 indicatt it 11 wajor
aiiuirptiotu aaentific ivd^menu and.
to tht aiient poatiblt. trimatet af the
viceruintiei ¦nboditd m tht nak
•iieeiretnt will be p*rem(ed along with
the Musithon t{ niL
I Tht propoaed gutdHmei ttited tfiat
tie appropnateneat 01 qoanufying ru**
for chemict!* m Ctomp C (Poattble
Huffltn GirunofenJ tperiTically IfcoM
ftgentt the* were on the boundary of
Croupe C *nd D (Not Oaaajfieble m to
Hirmir Carciftogerrntyl. woWd be
twdged on a caae-by<«»e bnia Sone
comanion felt thw qwiutavrt nak
•wriiMrM thouirf ao< be peKoneod M
aa/ agrat ia Croap C
Croup C iric'.jfin 1 «ndr rar.(t of
•gtmi iDclui.rj iB-i* fa't'lhe'e
tre poiiM^t rttwV.i in one tptc.ei m or.t
good bioamy Thui iht Age*:, fee-t
that many tge-ti m Crowp C Dt
am'ablt for quantnativt ni«
aiaeiimtnt but that iudg"irnu m -.S t
rtgard wili be made on a uie b)-cnt
« A ftw commentort felt that EPA
id tended <0 perform quantitative nc
•atimatet on aggregate tumor incidence
Whilt EPA will connder an mere tie m
total aggregtie turn on aa luigrttive of
potential caranogemcity EPA doet not
generally intend 10 make qutntttti'.ve
•atimatei of carcinogenic nik bated on
total aggregate tumor incidence
S The propoeed choice of body
surface area at an intenpeoea icaling
factor wit cntiuted by ttvaral
conuntnion who felt iktt body weight
wii alto tppropnate and that both
ntthodt ihoutd bt mid Tht OSTP
rtpon recogrvtftt thai both tcaling
facton art in common uie The Agency
feeii that the choice of the body aurface
area acaling factor can be jutuhed from
the data 
If "site treatrer.t cf waste liquids cr sludge cr
ccrta-mated liners cr soils is proposed (tefcre or after
rercval : r c r v-.e irpcur.dner.t) , tr.e owner/operator should:
c Calculate the anticipated incremental pollutant
emissions, discharges, and residues.
o Assess the additional ha2ards posed to human
health ar.d the environment.
o Plan for compliance with all applicable RCRA
regulations, as well as with the clean closure
standards set for the impoundment.
The cwr.er cperatcr should report the results of these
efforts :r. the clear, closure flan. The Agency reviewer
srculd evaluate this mforraticn to ensure that:
c Additicr.al emissions cr discharges are justifiable
arc r:r.:r.i:ec.
o Any residues are reroved to ar. appropriate offsite
management facility.
o All applicable RCRA regulaticrs are complied with
and, m particular, the clean closure standards
set according to this guidance are not exceeded.
Fcr sr.iprer.t cf waste liquids and sludges and contaminated
liners ar.c scils to hazardous waste treatment, storage or
disposal facilities, the owner/operator must:
c Identify and characterize the waste as hazardous
cr net according to the RCRA waste characteristics
ar.c lists contained m 40 CFR Part 261. tThe
owner/operator may attempt to delist the waste
according to 40 CFS 260.22).
o Comply with all applicable RCRA and authorized
state regulations fcr hazardous waste, generators
ar.d transporters (if appropriate) contained in
40 CFR Parts 262 and 263, respectively.
The ov-er 'operator should discuss each of these items m the
clean clcsure plan. The Agency should evaluate this
information ar.d verify that the wastes ir. question are
rraraced as hazardous wastes m compliance with all
applicable RCRA regulations. Attention should be paid to

wr.ezter t'r.e iac11 -1y recei
i".ar.dle the waste types ces
regarding the Lar.c d.spcsa
tir.e ar.d the bar. cr. lar.cfi
KDR15 5 06 9

1.1 Method 1312 is designed to determine the mobility of
both organic and inorganic contaminants present in soils.
2.1 The particle size of the soil is reduced (if necessary)
and is extracted with an amount of extraction fluid equal to 20
times the weight of the soil. The extraction fluid employed is
a function of the region of the country where the soil site is
located. A special extractor vessel is used when testing for
volatiles. Following extraction, the liquid extract is separated
from the soil by 0.6-0.6 urn glass fiber filter.
3.1 Potential interferences that may be encountered during
analysis are discussed in the individual analytical methods.
4.1	Agitation apparatus - an acceptable sgitation apparatus
is one which is capable of rotating the extraction vessel in an
end-over-end fashion at 30+2 rpm (see Figure 1). Suitable
devices known to EPA are identified in Table 2.
4.2	Extraction vessel - acceptable extraction vessels are
those that are listed below:
4.2.1 Zero Headspace Extraction Vessel 12HE) - This
device is for use only when the soil is being tested for the
mobility of volatile constituents (see Tasle 1). The ZHE is an
extraction vessel that allows for liquid/solid separation within
the device and which effectively precludes headspace {as depicted
in Figure 3). This type of vessel allows for initial liquid/solid
separation, extraction, and final extract filtration without
having to open the vessel (see Step 4.3.1). These vessels shall
have an internal volume of 500 to 600 mL and be equipped to
accommodate a 90-mm filter. Suitable ZHE devices known to EPA
are identified in Table 3. These devices contain viton O-rings
which should be replaced frequently. For the ZHE to be acceptable
for use, the piston within the ZHE should be able to be moved
with approximately 15 psi or less. If it takes more pressure
to move the piston, the O-rings in the device should be replaced.
If this does not solve the problem, the ZHE is unacceptable for
1312 analyses and the manufacturer should be contacted. The ZHE
Revision 1
December 1987

STCLTlr 36 checked after every extraction. If the de.vice con-
tains a built-in pressure gauge, pressurize the device to
50 psi, allow it to stand unattended for 1 -hour, and recheck
the pressure. If the device does not have & built-in pressure
gauge, pressurize the device to 50 psi, submerge at in water
and check for the presence fo air bubbles escaping from any
of the fittincs. If pressure is lost, check all fittings and
inspect anci replace O-rings, if necessary. Retest the device.
If leakage problems cannot be solved, the manufacturer should
be contacted.
4.2.2	When the soil is being evaluated for other than
volatile contaminants,- an extraction vessel that does not pre-
clude headspace (e.g. a 2-liter bottle) is used. Suitable
extraction vessels include battles made from various materials,
depending on the contaminants to be analyzed and the nature of the
waste (see Step 4.3.3). It is recommended that borosilicate
glass bottles be used over other types of glass, especially
when inorganics are of concern. Plastic bottles may be used
only if inorganics are to be investigated. Bottles are available
from a number of laboratory suppliers. When this type of ex-
traction vessel is used, the filtration device discussed in f
Step 4.3.2 is used for initial liquid/solid separation and fin'al
- extract filtration.
4.2.3	Sone 2HEs use gas pressure to actuate the ZRE piston,
while others use mechanical pressure (se-= Table 3). Whereas
the volatiles procedure (see Step 7.4) rsiers to pounds-per-
square inch (psj), for the mechanically -rtuated piston, the
pressure applied is measured in torque-i -:-.-pounds. Refer to
the manufacturer's instucticns as to the proper conversion.
4.3 Filtration devices - It is recommended that all filtrations
be performed in a hood.
4.3.1 Zero-Headspace Extractor Vessel (see Figure 3) -
When the waste is being evaluated for volaules, the zero-
headspace extraction vessel is used for filtration. The device
shall be capable of supporting and keepinc in place the fiber
filter, and be able to withstand the press-re needed to accomplish
separation (50 psi).
NOTE; When is it suspected that the class fiber filter
has been ruptured, an in-line class fiber filter may be
used to filter the material wit-:- the 2HE.
2 Filter holder - when the soil is being evaluated
than volatile compounds, a filter holder capable
ting a glass fiber filter and able to withstand 50
re of pressure. These devices shall have a minimum
volume of 300 mL and be equipped to accomodate a
filter si2e of 47 mm (filter holders having an
capacity of 1.5 liters or greater are recommended 3.

f o
or mo
n l
mum f
l n
Revision 1
December 1987

4.3.3 Materials of construction - filtration devices shall
be made cf inert materials which will not leach or absorb soil
components. Glass, polytetraf1joroethylene (PTFE) or type 316
stainless steel equipment may be used when evaluating the nobility
of both organic and inorganic components. Devices made of high
density polyethylene (HDPE), polypropylene, or polyvinyl chloride
may be used only when evaluating the nobility of metals. Boro-
silicate glass bottles are recommended for use over other types
of glass bottles, especially when inorganics are constituents
of concern.
4.4 Filters - filters shall be made of borosilicate glass
fiber, shall have an effective pore size of 0.6 - 0.8 um and
shall contain no binder materials. Filters known to EPA to meet
these requirements are identified in Table S. When evaluating the
mobility of metals, filters should be acid-washed prior to use
by rinsing with 1.0N nitric acid followed by three consecutive rinses
with deionized distilled water (a minimum of 1-liter per rinse is
recommended). Glass fiber filters are fragile and should be handled
with care.
4.5	pH meters - any of the comnmonly available pH meters are
4.6	ZHE extract collection devices - TEDLAR bags, glass, stain-
less steel or PTFE gas tight syringes are used to collect the volatile
4.7	Laboratory balance - any laboratory oalance accurate to
within + 0.01 g may- be used (all weight meas-.-^ments are to be within
* 0.1 g ).
4.8	ZHE extraction fluid transfer devices - any device capable
of transferring the extraction fluid into the ZHE without changing
the nature of the extraction fluid is recommended.
5.1 Reagent water - reagent water is defied as water in
which an mterferent is not observed at or ab': ;e the method
detection limit of the analyte(s) of interest. For non-volatile
extractions, ASTM Type II water, or equivalent neets the definition
of reagent water. For volatile extractions, :is recommended
that reagent water be generated by any of the following methods.
Reagent water should be monitored periodically for impurities.
5.1.1	Reagent water for volatile extractions may be
generated by passing tap water through a rarbon filter bed
containing about 500 g of activated carbc-. (Calgon Corp.,
Filtrasorb 300 or equivalent).
5.1.2	A water purification system (Millipore Super-Q or
equivalent) may also be used to generate reagent water for
volatile extractions.
Revision 1
December :98"

5.1.3 Reagent water for volatile extractions nay also
be prepared by boiling water for 15 minutes. Subsequently,
while maintaining the water temperature at 30 - 5°C, bubble
a contaminant-free inert gas.	nitrogen) through the
water for 1 hour. While still hoc, transfer the -^ater to a
narrow-mouth screv-caD bottle under zero heacispace and seal
wit1! a Teflon lined septum and cap.
5.2	Sulfuric acid/nitric acid (60/40 weight percent mixture*
H2SO4/KNO3. Cautiously mix 60 g of concentrated sulfuric acid with
40 g of concentrated nitric acid.
5.3	Extraction fluids (synthetic acid rain):
5.3.1	Extraction fluid €l - this fluid is made by adding
the 60/40 weight percent mixture of sulfuric and nitric acids
to reagent water until the pH is 4.20 + 0.05.
5.3.2	Extraciton fluid #2 - this fluid is made by adding
the 60/40 weight percent mixture of sulfuric and nitric acids
to reagent water until the ptt is 5.00 + 0.05.
^ote: It is suggested that these extxraction fluids be moni- !
tored frequently for impurities. The pH should be
checked prior to use to ensure that these fluids are
made up accurately.
5.4	Analytical standards shall :>e prep3:-2d according to the
appropriate analytical method-
6.1	All samples shall be collected using an appropriate
sampling plan.
6.2	At least two separate representative samples of a soil
should be collected. The first sample is used to determine it the
soil recsuires particle-size reduction and, if -esired, the percent
solids of the soil. The second sample is usee for extraction
of volatiles and non-volatiles.
6.3	Preservatives shall not be added to tuples.
6.4	Samples shall be refrigerated to mm.-nize loss of volatile
organics and to retard biological activity.
6.5	When the soil is to be evaluated for volatile contaminants,
care should be taken to minimize the loss of volatiles. Samples
shall be taken and stored in a manner to prevent the loss of
volatile contaminants. If possible, it is recommended that any
necessary particle-size reduction be conducted as the sample is
being taken.
Revision 1
December 1987

6.6. 1312 extric.s shOLld be prepared for analysis and
analyzed as soon as possible following extraction. If they need
to be stored, even for a short period of time, storage shall be at
4°C, and samples for volatiles analysis shall not be allowed to
come into contact with the atmosphere (i.e. no headspace). See
Section 8.0 (Quality Control) for acceptable sample and extract
holding times.
7.1	The preliminary 1312 evaluations are performed on a mini-
mum 100 g representative sample of soil that will not actually under
go 1312 extraction {designated as the first sample in Step 6.2).
7.1.1	Determine whether the soil requires particle-size
reduction. If the soil passes through a 9.5 mm (0.375-inch)
standard sieve, particle-size reduction is not required
(proceed to Step 7.2). If portions of the sample do not
pass through the sieve, then the oversize portion of the
soil will have to be prepared for extraction by crushing
the soil to pass the 9.5 mm sieve.
7.1.2	Determine the percent solids if desired.
7.2	Procedure when volatiles are not involved - Enough
solids should be generated for extraction such that the volume
of 1312 extract will be sufficient to support all of the analyses
required. However, a minimum sample size of 100 grams shall
be used. If the amount of extract generated cy a single 1312
extract will not be sufficient to perform all ":f the analyses,
it is recommended that more than one extraction be performed and
the extracts be combined and then aliquoted fcr analysis.
7.2.1	Weigh out a representative subsample of the soil and
transfer to the filter holder extractor vessel.
7.2.2	Determine the appropriate extraction fLuid to use.
If the soil is from a site that is east of the Mississippi
River, extraction fluid #1 should be used. If the soil is
from a site that is west of the Mississippi River, extraction
fluid #2 should be used.
7.2.3	Determine the amount of extraction fluid to add
based on the following formula:
amount of extraction fluid (mL) * 20 < weight of soil (g)
Slowly add the amount of appropriate extraction fluid to the
extractor vessel. Close the extractor bottl« tightly {it
is recommended that Teflon tape be used to ensure a tight
seal), secure in rotary extractor device, and rotate at 30
+ 2 rpm for 18+2 hours. Ambient temperature (i.e. temper-
ature of room in which extraction is to take place) shall
be maintained at 22 * 3°C during the extraction period.
Revision 1
December 1987

Note: As agitation continues, pressure .-nay build up within the
extractor bottle for some types of soil (e.g. limed or
calcium carbonate containing soil may evolve gases such as
carbon dioxide). To relieve excess pressure, the extractor
bottle may be periodically opened (e.g. after 15 minutes,
30 minutes, and 1 hour) and vented into a nood.
7.2.4	Following the 18 ~ 2 hour extraction, the material in
the extractor vessel is separated into its component liquid and
solid phases by filtering through a glass fiber filter.
7.2.5	Following collection of the 1312 extract it is re-
commended that the pH of the extract be recorded. The extract
should be immediately aliquoted for analysis and properly
preserved (metals aliguots must be acidified with nitric
acid to pH <. 2; all other aliguots must be stored under
refrigeration (4°C) until analyzed). The 1312 extract
shall be prepared and analyzed according to appropriate
analytical methods. 1312 extracts to be analyzed for metals,
other than mercury, shall be acid digested.
7.2.6	The contaminant concentrations in the 1312 extract are
compared to thresholds in the clean closure guidance manual.
Refer to Section 8.0 for Quality Control requirements.
7.3 Procedure when volatiles are involved:
7.3.1 The ZHE device is used to obta n 1312 extracts for
volatile analysis only. Extract resulti--; from the use of the
ZHE shall not'be used to evaluate the mc llity of non-volatile
analytes (e.g. metals, pesticiedes, etc. . The ZHE device
has approximately a 500 mL internal capacity. Although a minimum
sample size of 100 g was required in the Step 7.2 procedure, the
ZKE can only accommodate a maximum of 25 z of solid , due to the
need to add an amount of extraction fluid equal to 20 times the
weight of the soil. The ZHE is charged w:th sample only once and
the device is not opened-until the final extract has been col-
lected. Although the following procedure allows for particle-
size reduction during the conduct of the Procedure, this could
result in the loss of volatile compounds. If possible particle-
size reduction (see Step 7.1.1) should be conducted on the
sample as it is being taken (e.g., partic e-size may be reduced
by crumbling). If necessary particle-siz- reduction may be
conducted during the procedure. In carry.ng out the following
steps, do not allow the soil to be expose: to the atmosphere for
any more time than is absolutely necessar/. Any manipulation of
these materials should be done when cold 4"C) to minimize the
loss of volatiles. Pre-weigh the evacula~ed container which
will receive the filtrate (see Step 4.6), and set aside. If
using a TEDLAR* bag, all air must be expressed from the device.
Revision 1
December 1987

".3.2 Place the 2HE piston wirr.in the oody of the ZHE (it
¦*>ay be helpful f:rst to moisten the piston 0-r:ngs slig.icly wur.
extraction fluid). Advjst the piston wit-.ir. the ZHE oody to a
height that will minimize the distance the piston will have to
move once it is charged with sample. Secure the gas inlet/outlet
flange (bottom flange] onto the ZHE body in accordance witr. the
nanufacturer's instructions. Secure the glass fiber filter
between tr.e support screens and set aside. Set liquid inlet/out-
let flange (top flange) aside.
7.3.3	Quantitatively transfer 25 g of soil to the ZHE.
Secure the filter and support screens into the top flange of the
device and secure the top flange to the ZHE body in accordance
with the,manufacturer's instructions. Tighten all ZHE fittings
and place the device in the vertical position (gas inlet/outlet
flange on the bottom). Do not attach the extraction collection
device to the top plate. Attach a gas line to the gas inlet/out-
let valve (bottom flange) and, with the liquid inlet/outlet
valve (top flange) open, begin applying gentle pressure of 1-10
psi to a maximum of 50 psi to force most of the headspace out of
the device.
7.3.4	With the ZHE in the vertical position/ attach a
line from the extraction fluid reservoir to the liquid inlet/'
.outlet valve. The line used shall contain fresh extraction
fluid and should be preflushed with fluid to eliminate any air
pockets in the line. Release gas pressure on the ZHE piston
(from the gas inlet/outlet valve), open .~e liquid inlet/
outlet valve, and begin transferring extraction fluid (by
pumping or similar means) into the ZHE. Continue pumping
extraction fluid into the ZHE until the impropriate amount of
fluid has been introduced into the device.
7.3.5	After the extraction fluid has been added, immediately
close the inlet/outlet valve and disconnect the extraction fluid
line. Check the ZHE to ensure that all valves are in their closed
positions. Physically rotate the device : r. an end-over-end fashion
2 or 3 times. Reposition the ZHE in the vertical position with
the liauid inlet/outlet valve on top. Put 5-10 psi behind the
piston (if nesessary) and slowly open the liquid inlet/outlet
valve to bleed out any headspace (into a i-.:od) that may have •
been introduced due to the addition of ex-.raction fluid.
This bleeding shall be done quickly and st-3ll be stopped at the
first appearance of liquid from the valve. Re-pressurize the
ZHE with 5-10 psi and check all ZHE fittings to ensure that
they are closed.
7.3.6	Place the ZHE in the rotary extractor apparatus (if
it is not already there) and rotate the I'.iZ at 30 + 2 rpm for
18+2 hours. Ambient temperature (i.e. temperature of the room
in which extraction is to occur) shall be maintained at 22 + 3°C
during agitation.
Revision 1
December 1987

..3.. Following the 18 * 2 hour agitation oeriod, check
the pressure behind the ZHE piston ov cuickly ooenir.g and closing
the gas inlet/outlet valve and noting the escape of gas. If tr.e
pressure has not been maintained (i.e. no gas release observed),
the device is leaking. Check the 2HE for leaking and redo the
extraction with a new sample of soil. If the pressure within
the device has been maintained, the material in the extractor
vessel is separated into its component liquid and solid phases.
7.3.8	Attach the evacuated pre-weiahed filtrate collection
container to the licuid inlet/outlet valve and open the valve.
Begin applying gentle pressure of 1-10 psi to force the liquid
phase into the filtrate collection container. If no additional
liquid has passed through the filter in any 2 minute interval,
slowly increase the pressure in 10-psi increments to a maximum of
50 psi. After each incremental increase of 10 psi, if no additiona;
liquid has passed through the filter in any 2 minute interval,
proceed to the next 10 psi increment. When liquid flow has
ceased such that continued pressure filtration at 50 psi does
not result in any additional filtrate within any 2 minute period,
filtration in stopped. Close the inlet/outlet valve, discontinue'
pressure to the piston, and disconnect the filtration collection
NOTE: Instantaneous application of high pressure can
degrade the glass fiber filter and may cause
premature plugging.
7.3.9	Following collection of the 1212 extract, the extract
should be immediately aliquoted for anal sis and stored with
minimal headspace at 4°C until analyzed. The 1312 extract will be
prepared and analyzed according to the appropriate analytical
me thods.
8.1	Ml data, including quality assurance data, should be
maintained and available for reference or inspection.
8.2	A minimum of one blank (intraction fluid *~1) for every
10 extractions that have been conducted in an extraction vessel
shall be employed as a check to determine if =.-y memory effects
from the extraction equipment are occurring.
8.3	For each analytical batch (up to twenty samples), it is
recommended that a matrix spike be performed. Addition of matrix
spikes should occur once the 1312 extract has ^een generated
(i.e. should not occur prior to performance of the 1312 procedure).
The purpose of the matrix spike is to monitor :he adequacy of the
analytical methods used on the 1312 extract ani for determining
if natrix interferences exist in analyte detection.
Revision 1
December 1987

3.4	Ail cuality control measures described m tne appropriate
analytical methods snail be followed.
3.5	The method of standard addition shall be employed for
each analyte if: 1) recovery of the compound from the 1312
extract is not between 50 and 150%, or 2) if the corcentration of
the constituent measured in the extract is within 20% of the
appropriate regulatory threshold. If more than one extraction is
Seine run on samples o£ the same waste (up to twenty samples),
the method of standard addition need be applied only once and the
percent recoveries applied on the remainder of the extractions.
3.6	Samples must undergo 1312 extraction within the following
time period after sample receipt: Vclatiles, 14 days; Semi-
Volatiles, 40-days; Mercury, 28 days; and other Metals, 180 days.
1312 extracts shall be analyzed after generation and preservation
within the following periods: Volatiles, 14 days; Semi-Volatiles,
40 days; Mercury, 23 days; and other Metals, 180 days.
9.1 None available.
10. 1 None available.
Revision 1
December 1987

Ace tone		.				
Acryloni trile	.				
n-Butyl alcohol	
Carlson disulfide.....	
Carbon tetrachloride.....			
Chlorobenzene. 		-.
1, 2-Dichloroe thane				
Ethyl acetate	
£thyl benzene			
Ethyl ether	
Isobutanol	.				
Methylene chloride 		
Methyl ethyl ketone 			
Methyl isobutyl ketone 	
1, 1,2,2-Tetrachloroethane.		
1.1.2-Trlchloroethan	e	
Vi nyl chloride			 ..
1 CAS So.
Revision 1
December 1987

Analytical Testing and
Consulting Services, Inc.
1 Warrington, PA
(215) 343-4490
4-vessel device
Associated Design and
Manufacturing Company
Alexandria, VA
(703) 549-5999
4-vessel device,
6-vessel device
EPRI Extractor			

6-vessel device^
16-vessel device
IRA Machine Shop and
Santurce, PR
(6091 T52-4004
Lars Lande Manufacturing
Whitaore Lake, HI
(313) 449-4116
10-vessel device
5-vessel device
Milwaukee, WI
(414) 643-2850
6-vessel device
*Any device that rotates the extraction vessel in an end-over-end
fashion at 30 + 2 rpm is acceptable.
^Although this device is suitable, it is not cnvnercially made. It
may also require retrofitting to accommodate THE devices.
Revision I
December 1987

Model No.
Analytical Testing i Con- 5
suiting Services, Inc..«..|
Associated Design & Manu-
facturing Co			
Millipore Corp.
Warring tor., PA.
<215> 343-4490.
Alexandria, VA
(703) 549-5999.
Bedford, MA,
(800) 225~3384.
j C202, Mechanical
' Pressure Device
Pressure Device
SD1 P581 C5, Gas
Pressure Device
Micro Filtration Systems...
Dublin, CA

14'2 mm

(415) 828-6010	
Millipore Corp. 		
Bedford, MA

{800} 225-3384	
142 mra

47 nun
Nuclepore Corp	
Pleasanton, CA
142 mm

(800) 682-7711 	
47 mm
*Any device capable of separating the liquid from the solid phase of
the soil is suitable, providing that it is chemically compatible with
the soil and the constitutents to be analyzed. Plastic devices (not
listed above) "nay be used when only inorganic contaminants are of con
cern. The 142 mm size filter holder is recom-snded.
s i ze^
whatnan Laboratory

Products, Inc 	
Clifton, NJ

(201 ) 773-5800	
^Nominal pore size
Revision 1
December 1987

r"gu'e 1. Ro:a"y Ag;tation
Revision i
Decembe* 1987

Figure 2. 2ero-Headspace Extraction Vessel
liquid inlet/outlet valve
1 '
¦£ 11 ter-
waste and

top flange
-V> body
VITON o-rings

bottom flange
pressurizing gas inlet/outlet valve
Revision 1
December 1987

1312	,
f i i.il a*«r)<
r*uii" it
¦ nnpruti
- - o "•

^ Cr\S-* ^
Nay $ iggf
••i'.r>,.'>'i7.	ct I'-r^t "Surfac.- Iw^oiinttof-ot Clran Closure
•luicancf H»nuAl*
J ^'..f. Sar ijckt-r, CMef
. '•bF)
office r>as rfviowd to* draft t/jiunc" eanual ••r.titlrtf "^urno
cun-:p#»nt C1j4:i Llosurr <c*-*¦' for bj yevr ofiCt In "arcla WilliAra*% smacraatj•. .iol-->*
t, ri I J, 1V'7.
I. Accord nu t? tr-t jrc-rn *n<< *st#-hsMn<, residual contaminant
ronc*-ntr«t 1 or- Uvjls wMcn t.'so owr.i.r/o^tretor cai. JenHinstrat..
Afr Krctect1y ot j.uMIc nv?a 11r. ««k! thr »*nvironrvnt. Pwrsuint
\u t»- oraft	cental, tar^i-t levels " '<~* ias»-c
v/h stincart's as t>r	ContannaM l*v»l$ (Kls),
'•.'r*rrr nc° _'c< JS for tT'rs^oli cnntanmer.ts ('JF['4 ). i'Isii Sj*-C 1 f lc
jSe* Tor no;it'ir^ir,i#|f4, cnniaiOfidnt s (¦fSi,<). «n;i Mtiorni
MM-nt r-uaMtj Stan-iar.:* (*AAp$), »"*»«-v»'r, accorjlfj tr.
fv r.rafr y.ii^ane.:, t»u- A$vrcy )« „i/if no* In th*- ,'rocr-ss
jrvcslf-; erl T"1n^?i7ir,-, a*1«M t1 cnu i KCI.s tnc «1ll Cur.t1/U!r* t-.
ar <<• o*rr t'w- i \t ? -»rral /»ars. Furtr.^rpcrc-, PAA'JS arr
iviilat lf. T^r ci 1/ si* entile®U or cr.tclcal »jr^uj.s anr tf.r
iir^r.rr.e particulates.
1h> ^u<<34f>c	or: to Hit oti-.rr txlstlnv, limn?* ct
envl rore»»rtal ttanoar-"s, cr1l«.n«t «no ^u1danc<-& wr1cl> w> Lf
usei: to cvaluait t»ir ci»*«t ti Uct wt a clearly
, .	»astly rff^r-nCcO list r>f tar'^t I *. w»* I * »ur?lrn of decision raking tvr - otn tr-.- /ujuncy ans thk
owner/cp-rator. 'lso, conT^slan cf» tf>< ^drt af an ow«er/optfator
5 J	rt5«re1nv# rt?1co»l ccfttaflntnt csnc^ntration	wtneft n»St
5-*»	«tt 'or cieaii cio»ure car {<¦•£ to dos«rtfi «nlcr r?sult
In «aoUlonal t lc«* at.c ri»«ou;» ®*^,*-rc«1tur(*.
fH-CT:Kurrvski :tlc:D-670';:^/i/c7:Conirol ft.ll-3o7-.-7:UiSk f3:FILt COOE:DlKK;

2. Setting target levels of hazardous constituents at detection
limits seees to be the better choice, even though It mould then
be necessary to Identify the analytical or measurement technique
And the related detection Halt used to establish each target level.
As suggested 1n the draft guidance, continuous updating ef
these teehnlcpes and the associated detection limits would be
necessary. Howevtr, 1t would be considerably easier to modify
a referenced technique than to re-establish target levels.

3.	The draft guldence rtcowends the use of the Extraction Procedure
(CP) for ratals and the Toxicity Characteristic leeching
Procedure d analysts, along with a full bydrogeologtcal
study of the site, 1s of the upmost Importance when making a
case by case determination of clean closure using background
levels. A closure plan which is proposing to clean to background
levels arxv 1s lacking the above mentioned Information should be
deemed Insufficient and vnepprovable.
The following comnents address other areas of concern not spectMd>
tsked 1n the eemorandue.
5.	(Pfr 1-11) If stabilization techniques are employed to meet the
Agency's human health criteria, haw will such techniques be
evaluated? Mill there be a procedure set up necessitating certain
test to evaluate the stabilization process?
, 6- (Pg ?-*> Under Waste Sampling and Analysis flaa. what are the
additional hazardous constituents thatshould be considered
j tb	besides Appendix VIII and how will CPA substantiate regulating
7. (Pg ?-3) What Is the rationale fer retiring four samples tram

9# {Pg ?-') H"J the decent »1 nation Method used for equlpaent
require sow for* of QA/QC testing?
IU. (Pg 3-3) If there are certain circumstances 1r> trfilch target
levels, bated on MCL's, RFD's aV JiSO's, ma/ be lowered; *111
there be any exemptions for higher target levels (1«e,, areas
with low population, regions with tow precipitation aim great
depths to groundwater)?
(Pg. 3-3) If elections are to be allowed. It N) be a preferable
alternative to create a risk range for target levels Instead of
a specific level to allow for flexibility and the abllltjr to
address site specific factors.
(Pg 4-2} For each ley step In the surface Impoundment clean
closure, has an/ data been generated to give an idea oti the
range of cost and anticipated timeframe f If so, will the data
timur/ be available so closure submittals can realtsttcal)y be
^^->3. (Pg 4-3) The Oecaber 16, 193$, regulation date should be
corrected to December 19, 19B6,
14. (Pg 4-1?) Are there eriy other acceptable methods for taking
soil core.samples beside * split spoon staler? Shouldn't
other bptiiMs be mentioned In this guidance annual?
bec: V.	Honker (68-CP)
W.	Taylor (6H-CE)
0.	Denmon (6H)
C.	Ronqulllo (6H-C)

In addition, a leaching procedure •followed by an analysis
ot" the leachate and comparison ot the leachate to the -final
cleanup targets for ground water may be necessary to evaluate
potential threats to ground water -from residual soil
contamination. The Agency has devised a soils/waste mixture
leaching procedure, I nown as the Synthetic ("'re ss mptioa Leach
Test (SFLTjthat it generally believes may be appropriate ¦for
evaluating the potential impact of contaminated soils on
ground-water quality. (See Append 1;: F for a description of
this procedure) . Although neither the SF'LT nor any other
leachinq te = t 
~ —	. o.c:
-oov m e.i.wik ¦.
'•i- OH n o
-.n.- •.
cT I
I 'J*).

~R1= 3265-e
SA?= 535-4
lc-f r'-.s • ** > "j
— A	^ i- I
-i X(
» "¦*

after approval return TO Dave Levy (PM-223) 382-7206 415 West Tower
t PA Form 1300-2 (6 711


SS> 2 g
Oc'«I 0*
Submittal for Red fiortfer Review of Surface
Impoundment Clean Closure Guidance Manual
Marcia E. Williams, Director
Office of Solid Waste	t
J. Winston Porter
Assistant Administrator
Solid Waste and Emergency Response
Attached are; (1) the Surface Impoundment Clean Closure
Guidance; (2) an executive summary of the guidance; and, (3) a
TRANSMITTAL MEMORANDUM from you to Jack Campbell so that the
guidance may enter simultaneous Red Border and 0MB review. This
is a final version of the document, having been revised based on
extensive regional office technical staff review, and on comments
from OWPE and CERR.	" " "
The Clean Closure Guidance Manual is written for RCRA
facility owners and operators of surface impoundments, and for
regional permit writers. The manual provides detailed information
on EPA's policy for clear.f closure by removal of waste, providing
evaluation criteria for setting clean-up target levels and pro-
cedures for assuring that they are met. The manual describes a
comprehensive process for assuring that no environmental threat
remains at the facility, following closure activities, since the
implications of completing closure by removal of waste is that
the owner or operator is not subject to any further regulatory
control, including corrective action, and is relieved of any
financial responsibility.
The manual supplements the RCRA Guidance Manual for Subpart G
Closure and Post-Closure Care Standards and Subpart H Cost Estima-
ting Requirements {January, 1987). It provides preliminary clean-U"
target levels for ground water, surface water, soil, and air, basec
on CPA-approved health criteria. It also provides direction on
establishing final clean-up targets after considering site specific-
factors, such as chemical mixtures, background levels, detection
limits, site specific exposures, and sensitive environmental syste

- 2 -
The manual makes extensive reference to other EPA technical guidance
documents rather than duplicating the technical information contained
in each. I have attached some introductory sections of the manual
to briefly describe the contents, and to illustrate the process of
completing a clean closure demonstration.
Please sign the memorandum transmitting the proposed rule to
Jack Campbell for Red Border and DMB review.
At tachments
cc: Joseph Carra

c-f c.anioe - containing wjste under acidic conditions may
result in the -formation or h>orogen cyanide. utner leaching
test variations may be necessary 1+ interactive ejects on
mobility are caused by non-aqueous solvents, -tor example, or i ~
?n aqueous phase leaching medium may underpredict potential
mobility due to site and waste constituent characteristics.
In determining the appropriate leach test ¦for the
evaluation of contaminants of concern at a specific site, the
owner or operator, in consultation with the Agency, should
consider relevant hazardous constituent properties, the
pnysical and chemical characteristics of the soil/waste matri::
at the site, and local c1imatolog1cal factors. Factors th.t
should be considered include the following:
Hazardous Constituent Properties
o Chemical £trueture C1 ass 1f1cat 1 on, and
tonding (Organic vs. Inorganic, Ionic
.=. Co v a 1 en t, etc.)
o Solubl1ity
o Octano1/Water or Other Partitioning

Organic Caroon Absorption Coefficient
Volatility "e.g., Henry s Law Constant)
Dissociation Constants 

) Deg-radation Potential (Hydraulics, fiodesr-adat i Qn Soi 1/Uaste flatri.-: Character!sties Cation E::chanqe Capacity Soil pH and EL Soil Classification (i.e., Clay, Silt, and Sand Content) FcTticie 5.ire Distribution Forosity UnsatJated Hydraulic Conductivity

CI ima toicgica 1 Char^ctet-istics
o Precipjtation Faterns (Volume, Frequency, etc,)
o pH o-f Local or Regional Precipitation
The choice of a specific leach test should be supported by an
analysis of the relevant factor, such as those listed above,
considering the lilely -future use o-f the site < industrial,
waste management, residential, etc.).
As an alternative approach to the use o-f a leach test tor
evaluating soil contaminant5. the owner or operator may choose
to perform an analysis or the waste, soil, and c1imatologjcal
conditions, considering such factors as are listed above, to
demonstrate that the expected concentrations of any
constituents that could leach ¦from any contaminated section o-f
the subsurface soils would not exceed the -final ground-water
cleanup targets. This analysis, which would require
appropriate technical justification and should rely as fHuch -as
possible on data (such as the results of published -field
studies conducted under environmental conditions similar to
those at the site o-f the closing unit)-, should be based on
conservative assumptions related to -future changes in
environmental conditions le.g., the use of the site -for future

non-hazscdous waste management;. The analysis should not
assume any attention in any uncontaminated soils that may e::ist
between the contaminated soil :one and the ground water. An
•l^inC to predict
analysis based on simulation modelling to predict the effects
of mechanical dispersion or dilution in the uncontaminated soil
rone would not be acceptable, due to the uncertainties
associated with such predictive modelling.
At the present time, studies are being designed to more
« A" Wint
•fully m m i u u k u various methods for evaluating leaching of
hazardous constituents from contaminated soils. Further
guidance will be provided by the Agency upon completion of
these studies. It is recommended that the owner or operator
review the procedures and methods described in Sections 8 and 9
and Appendi;: J of Fetitions to Delist Hazardous waste.
EPA/530-SW-S5-003, as well as SW-846, to assist in determining
teh appropriateness of any particular leaching procedures for
evaluating contaminated soils. Until more definitive guidance
is available, the owner or operator should determine the most
appropriate leaching procedure, and provide technical
justification to support the selected procedure based pn site
and waste conditions at the time of closure. For additional
assistance on selection of a leaching procedure, the
owner/operator may contact the Technical Assessment Branch of
the Office of Solid Waste in Washington, D.C. (202/7-82-4764) .

If it has be^n determined during the site characterization
process that a surface water pathway for contaminant
migration exists, a surface water sampling and analysis pro-
gram should be implemented. Surface water and sediment sam-
ples should be taken during the excavation and disposal
process if an event such as flooding, overtopping, breaching
of containment dikes, or discharging of contaminated ground
water to surface water is likely to have occurred. A final
set of samples should be taken after the closure is com-
pleted. The samples will be taken at the dovngradient boun-
dary of the surface impoundment area unless it has been
determined that surface water is being contaminated by dis-
charge from contaminated ground water. The existence of
this contamination situation should have been determined
during the initial 6tudy of the site outlined in Section 2.4
(Surface Water Evaluation). If this is the case, the sur-
face water and sediments should be sampled at the point
where the ground water discharges into the surface water.
The number of samples and sampling technologies and the
rationale for their selection to be used should be outlined
in the closure plan. The surface water samples should be
analyzed for total constituents. The sediments should be
analyzed by use of a leaching test, to evaluate effects on
aquatic organisms.

Sampling is also required to confirm the effectiveness of
equipment decontamination procedures. The contaminants of
concern need to be considered when designing an equipment
decontamination program, the closure plan should include
this discussion.
An assessment of decontamination can be accomplished by
visual observation, wipe sampling, cleaning solution analy-
sis, and permeation testing, all of which are discussed in
Occupational Safety and Health Guidance Manual for Hazardous
Waste Site Activities (NIOSH, 1985) and in the Guide for
Decontaminating Buildings, Structures, and Equipment at
Superfund Sites (U.S. EPA, 1985b). The reader should refer
to these manuals for further guidance on evaluating
decontamination methods.

NIOSH, OSHA, USCG, U.S. EPA, 1985, Occupational Safety and
Health Guidance Manual for Hazardous Waste Site
U.S. EPA, 1984, Unsaturated Zone Monitoring for Hazardous
Waste Land Treatment Units, U.S. EPA OSWER, Washington,
DC, SW-84-004.
U.S. EPA, 1985a, Petitions to Delist Hazardous Waste,
U.S. EPA, 1985b, Guide for Decontaminating Buildings,
Structures, and Equipment at Superfund Sites,
U.S. EPA, 1986a, RCRA Ground-Water Monitoring Technical
Enforcement Guidance Document, Office of Waste Programs
Enforcement, Office of Solid Waste and Emergency
Response, OSWER Policy Directive No. 9950.1.
U.S. EPA, 1986b, Test Methods for Evaluating Solid Waste,
SK-846, 3rd Ed.

Appendix A
The $265,228 clc..»ure rules proposed on July 26, 1982, and
promulgated March 19, 1987, retain the basic format of
existing regulations by allowing owners and operators to
choose between removing hazardous wastes and waste residues
and terminating responsibility for the unit, or retaining
wastes and managing the unit as a landfill. The require-
ments for both choices are made more specific in 5265.228.
Similar requirements for closure of waste piles are found in
If the owner or operator chooses not to remove or
decontaminate the waste and waste residues, then the rules
promulgated today provide that the owner or operator must:
(1) eliminate free liquids by either removing them from the
impoundment or solidifying them, (2) stabilize the remaining
waste and waste residues to support a final cover,
(3) install a final cover to provide long-term minimization
of infiltration into the closed impoundment, and (4) perform
post-closure care and ground-water monitoring.
Sections 265.228 and 265.258 {like the corresponding Part
264 regulations for permitted units) allow owners and
operators of surface impoundments to remove or decontaminate
wastes to avoid capping and post-closure care requirements
($265,228 (a) (1) and $265.258(a)l. They must remove or
decontaminate all wastes, waste residues, contaminated
containment system components (e.g., contaminated portions
of liners), contaminated subsoils, and structures and
equipment contaminated with waste and leachate. All removed
residues, subsoils, and equipment must be managed as
hazardous waste unless there is compliance with the
delisting provisions of $261.3(d).
The new requirements for closure by removal differ
significantly from the previous Part 265 requirements in one
respect. The previous interim status requirement in
$265.228(b) required owners or operators to remove all waste
residuals and contaminated soil or to demonstrate, using the
procedures in $261.3(c) and (d), that the materials remain-
ing at any stage of the removal were no longer a hazardous
waste. Once an owner or operator made a successful demon-
stration under $261.3(c) and (d), (s)he could discontinue
removal and certify closure.

Under 5261 .2(c) and (d) , materials cc-.tmi-j'.ed w^t.u. listed
waste fas evidenced by the presence of Appendix VIII ccr.szi-
tuents} are hazardc 5 waste by definition unless the
material is delisted. Materials contaminated with charac-
teristic wastes, hcvever, are cr.ly hazardous wastes to the
extent that the material itself exhibits a characteristic.
Thus to r.eet the old closure by removal standard, owners or
operators of characteristic waste impoundments had only to
demonstrate that the remaining material did not exhibit the
characteristic that first brought the waste in the impound-
ment under regulatory control.
This demonstration, however, arguably allowed significant
and potentially harmful levels of hazardous constituents
(i.e., those contained in Appendix VIII of Part 261) to
remain in surface impoundment units without subjecting the
units to landfill closure, post-closure care, or monitoring
requirements. Waste deemed hazardous because of
"ignitabilitv," for example, may contain Appendix VIII
constituents of environmental concern that are totally
unrelated to the properties of the waste that cause it to
"fail" the igntability test. Thus demonstrating that
residuals are no longer ignitable may be insufficient to
confirm that the remaining material does not pose a threat
to public health and/or the environment.
Hence, the language "or demonstrate what remains is no
longer a hazardous waste" has been dropped from the interim
status regulations because it is inconsistent with the
overall closure performance standard requiring units to
close in a manner that eliminates or minimizes the post-
closure escape of Appendix VIII constituents. Moreover, the
language is inconsistent with the policy that interim status
and permitted units should be equally protective of ground-
water as required by RCRA. S3005 U). Consequently, today's
amendment to $265,228 allows "clean closure" only if the
owner or operator removes or decontaminates all hazardous
wastes and hazardous constituents.
Readers should note that units that closed under the
previous 5265.228 by demonstrating that the waste residuals
or contaminated soils do not exhibit a characteristic, may
be required under Section 3005 (l) of RCRA to undertake
additional removal, ground-water monitoring or corrective
action to meet the §264.228 closure by removal standard.
Section 3005 (i) requires all landfills# surface impound-
ments, waste piles, and land treatment units that received
waste after July 26, 1982, to meet the same ground-water
monitoring and corrective action standards that are appli-
cable to new units, permitted under Section 3005(e). Since
permitted units would have had to meet the $264,228 removal
standard or be subject to 40 CFR Part 264 Subpart F ground-
water monitoring, Section 3005(i) requires that all

regulated units ultimately meet the S264.22B closure by
removal standard or be sublet to Part 264 Subpart F -cr.i-
ton.ng. For a more complete interpretation of Section
3C05(i) as it relates to interim status closures, see the
proposed amendment of $270.l(i) (51 FR 10"C6, March 28,
1985). In addition, characteristic waste units that closed
under the previous 5265.228 may be required to undertake
additional soil removal, ground-water monitoring or
ground-water clean-up pursuant to an enforcement action
initiated under $3003(h). Section 3008(h) authorizes the
Agency to impose corrective orders to ensure protection of
human health and the environment from all types of releases
of hazardous waste or hazardous constituents at interim
status facilities.
The question has also arisen during the implementation of
previous closure by removals whether $265,228 requires
consideration of potential ground-water contamination in
addition to soil contamination. The answer to this question
is yes. The closure by removal requirements in
§265.226(a)(1) and (b) requires removal or decontamination
(i.e. flushing, pumping/treating the aquifer) of "underlying
and surrounding contaminated soils." Since contamination of
both saturated and unsaturated soils my threaten human
health or the environment, the Agency interprets the term
"soil" broadly to include both saturated and unsaturated
soils containing ground water. Thus the closure by removal
standard requires consideration of both saturated and
unsaturated soils. Uncor.taminated ground water is,
therefore, a requirement for "clean closure" under Part 265
(and Part 264).
EPA's Interpretation of the "Remove or Decontaminate"
The issue concerning how much removal or decontamination of
wastes and waste residues is necessary to protect human
health and the environment is relevant in a broad range of
regulatory contexts currently being examined by the Agency
including closure and corrective actions under RCRA and
response actions under the Comprehensive Environmental
Response Compensation and Liability Act (CERCLA) programs.
The removal and decontamination issue arises directly from
differences in regulatory strategy between disposal and
storage. A storage unit holds wastes temporarily and wastes
are eventually removed for treatment or disposal elsewhere.
The goal at closure is to leave no materials at the storage
site that require further care. In contrast, a disposal
unit, by definition, is closed with wastes and residues
remaining at the site. The goal at closure is to assure
A- 3

that these rer.air.ir.g wastes and residues are managed m a
ranr.er that protects human health ar.d the envirorjr.er.t.
There is no need fcr pcst-closure oversight of storage ur.it;
since all potentially harmful wastes ar.d contaminated
materials are removed. This is not true for disposal units;
her.ce, the Agency has promulgated regulations requiring
post-closure care for disposal ur.its. (For further
discussions on proposed landfill closure options see
preamble discussions to 55264.310 and 265.310 Federal
With regard to storage units regulated under both Parts 264
and 265, the Agency intends that the terms "remove" and
"decontaminate" mean removal of all wastes, liners,
leachate, and materials contaminated with the waste or
leachate (including ground water) that pose a substantial
present or potential threat to human health or the
environment. The Agency recognizes that at certain sites
limited quantities of hazardous constituents might remain in
the subsoil and yet present only insignificant risks to
human health ar.d the environment. Because regulations for
storage facilities require no further post-closure care, the
Agency must be certain that no hazardous constituents remain
that could harm human health or the environment (now or in
the future). To provide the necessary level of assurance,
the Agency will require owners or operators to remove all
wastes and contaminated liners and to denonstrate that any
hazardous constituents left in the subsoils will not cause
unacceptable risks to human health or the environment. The
Agency will review site-specific demonstrations submitted by
facility owners and operators that document that enough
removal and decontamination has occurred so that no further
action is necessary. Owners or operators wishing to avail
themselves of the site-specific removal op-ion must include
in their closure plans specific details of .ow they expect
to make the demonstration; including sampling protocols,
schedules, and the exposure level that is intended to be
used as a standard for assessing whether removal or
decontamination is achieved.
The closure demonstrations submitted by facility owners and
operators must document that the contaminants left in the
subsoils will not impact any environmental media including
ground water, surface water, or the atmosphere in excess of
Agency-established exposure levels, and that direct contact
through dermal exposure, inhalation, or ingestion will not
result in a threat to human health or the environment.
Agency-established exposure levels are those that have
undergone peer review by the Agency. *t the present time
these include water Quality standards -."id criteria (45 FR
79318, November 28, 1980, 50 FR 30784), health-based limits
based on verified reference doses (RfDs) developed by the
Agency's Risk Assessment Forum (USEPA, ECAO-CIN-475, January

19S65 ar.d Carcinogenic Potency Factors (CPFi developed ty
the Agency's Carcinogen Assessment Group (CHEA, EPA/503/-
8-83^012 FF, September J98$>, or site-specific Agency-
approved public health advisories issued fay the Agency for
Toxic Substance ar.c Disease Registry of t.*;e Centers of
Disease Control, Department of Health and Kur.ar, Services,
The Agency is currently compiling toxicity information on
many of the hazardous constituents contained in Appendix
VIII to Part 263. The facility owner and operators should
check vith the Agency for the latest toxicity information.
However, for some hazardous constituents, formally
established exposure levels do not yet exist. If no
Agency-established exposure limits exist for a hazardous
constituent and the hazardous constituent c&anot be grouped
with other constituents with known toxicity characteristics,
then the facility owner or operator must either remove the
constituent down to background levels,, submit data of
sufficient quality for the Agency to determine the
environmental and health effects of the constituent, or
follow lar.dfill closure and post-closure requirements. Data
submitted by the owner or operator on environmental and.
health effects of a constituent should, when possible,
follow the toxicity testing guidelines of 40 CTR Parts 79?
and 793 1=0 FR 39552, September 27, 1985), The Agency does
rot believe there are many situations where developing
exposure levels will be a realistic cpt.on for owners and
operators because t>.e testing required by 40 CFR Parts 797
and 798 to produce reliable toxicity estimates is expensive
and time-consuming.
The Agency believes it is necessary to present policy on the
appropriate point of exposure for the various pathways of
exposure ir. order to provide some national consistency in
dealing with the potential impacts of the release of
hazardcus constituents from closing units. The following
point of exposure was chosen because the Agency believes it
represents a realistic and at tfte s&me tine conservative
estinate cf where either environmental or human receptors
could be exposed to the coneamnants released from the unit.
For the purpose of waiting a closure by removal demonstra-
tion, the potential point of exposure to Jiajardous waste
constituents is assumed to be directly at tbe unit boundary
for the routes of exposure (surface-water contact, ground-
water ingestion, inhalation, and direct contact!. Potential
exposure at the unit boundary must be assumed because no
further oversight or monitoring of the unit is required if
the unit is closed by removal. (Recall that the land over-
lying a unit that closes by r^oval may be transferred and
developed freely without giving notice of its prior use.J
Therefore, no attenuation of the hazardous waste consti-
tuents leaching from the waste residues can be presumed

tc occur be fere the constituents reach expesure poir.ts.
contrast, delisted solid waste renair.s subject to the reg-
ulatory controls promulgated by the Agency under Subtitle 2
ci RCRA. Subtitle D contains performance criteria for the
management of non-ha2ardous waste. Although the Agency is
currently assessing whether more specific Federal regulatory
requirements are needed for waste management under Subtitle'
D, most states have adopted specific regulatory requirements
for Subtitle D waste management. Therefore, even though a
waste may be delisted, its management continues to be con-
trolled. In contrast, closure by removal would not be
followed by any regulatory controls; hence, an environmen-
tally conservative approach is needed to assure no further
risk to human health and the environment. In addition,
unlike the current "delisting procedure" that is based on a
generic process that only considers the ground-water route
of exposure, the demonstration procedure discussed here is
site-specific, considers all potential exposure pathways,
and assumes no attenuation.
The site-specific demonstration should be conservative in
-the sense that it eliminates the uncertainties associated
with contaminant fate and transport, focusing on the waste
contaminant levels and contaminant characteristics. There-
fore, arguments relying on fate and transport calculations
will not be accepted. The Agency is pursuing this rela-
tively conservative approach at this tiire because we are
confident that -it will be protective of human health and the
To make the demonstration with respect to the direct
contract pathway, owners or operators must demonstrate that
contaminant levels in soil are less than levels established
by the Agency as acceptable for ingestion or dermal contact.
Total waste constituents levels in soil should be used for
this analysis. Arguments based on exposure control measures
such as fencing or capping will not be acceptable since the
long-term future use of the property cannot be reliably
controlled and hence the long-term effectiveness of these
treasures is uncertain.
To make the demonstration with respect to the ground-water
pathway, owners or operators must remove enough contaminated
soil and saturated subsoils (i.e., ground water) to demon-
strate that constituent levels (RfD or CPF) and that resi-
dual contaminant levels remaining in the soil will not
contribute to any future contamination of ground water.
(Note: this demonstration may in some cases require
constituent-specific ground-water data beyond that required
by SS265.90—100). The demonstration related to residual
soil contamination levels must show that levels of
constituents found in leachate from the residual soil

ccr.ta.Tir.atic.- are r.ct above Ager.cy-estarlished expcs.re
levels. Levels of constituents in leachate maybe estir.atec
based on known characteristics of the waste constituents
(e.g., solubility and partitioning coefficients) or
determined by the results of actual soil leaching tests.
The Agency is exploring the appropriateness of using the
extraction procedures (but not the acceptable contaminant
levels) found in the Toxicity Characteristics Leaching
Procedure (TCLP), Federal Register of June 13, 1986 (51 FR
21648). The current EP Toxicity leaching procedure is
insufficient for this demonstration because it does not
capture the organic constituents in the waste.
The analysis of potential air exposures should assess
contaminants migrating from the soils into the atmosphere.
The demonstration should include emission calculations,
available monitoring data, and safe inhalation levels based
on Agency-established exposure levels.
The potential surface water exposure analysis should compare
Ager.cy-established water quality standards and criteria (45
FR 79318, November 28, 1980) with the levels of constituents
that may leach from the residual contaminated soil. Tests
described previously should be used to estimate the level of
constituents in the leachate. The surface water exposure
analysis should also consider existing surface water
contaminant concentrations.
40 CFR 264.113 and 265.113 require the owner/operator to
treat, remove, or dispose of all hazardous waste in
accordance with the approved closure plan within 90 days
after receiving the final volume of hazardous wastes or 90
days after approval of the closure plan. Under 264.112 the
owner/operator must submit a closure plan at least 180 days
before he expects to begin closure. The plan should include
a topographic or county map, description of unit, and a
diagram, showing relationships to other points or structures
of the facility. A complete and detailed list of hazardous
wastes, which were disposed, treated or stored at"the unit
should be included. If the owner/operator decides on the
clean closure option, he develops a closure plan according
to $265,112 and submits it to the Regional Administrator
(RA). The RA will first review the closure plan to see if
it meets the requirements. If it is incomplete or inade-
quate, he will notify the owner/operator of the additional
information required, that must be provided. The owner/
operator must submit a revised plan, the RA will review the
revised plan and if approved, closure of the unit can begin.
If the unit closes under interim status there will be a
public review period.

Appendix 2
twc d:kese:csal ranccy. sailing
The procedures in Peti'.lcns to Delist Kazarfc-s Wastes
<;5c51 outlines the following collection process to cbtam
samples at randomly spaced FOir.ts on a horizontal grid.
1.	On a diagram, divide the area to be sampled into
sections of equal area. If the area is under
40,000 square feet, then it should be divided into four
equal quadrants. If the area is over 40,000 square
feet, then it should be divided into equal sections of
not more than 10,000 square feet each.
2.	Divide each quadrant or section into an imaginary
10 x 10 grid to get 100 squares {or rectangles) of
equal size. Number the grid lines in each dimension
from 1 to 9.
3.	For each section, determine the number of sampling
points necessary to characterize the area. This nuxrber
will depend on the degree of spatial variability within
the surface impoundment.
4.	Select a two-digit number using a random number table.
Repeat this procedure until you have one two-digit
number io'z each sampling point in the section. (Random
number tables are available in any introductory
statistics text or handbook.)
5.	Locate the grid intersections whose coordinates
correspond to each of the two-digit random numbers.
These intersections are the locations of the randomly
selected sampling points.
€. Sarple each selected grid point vertically along the
entire distance from the top to the bottom of the
surface impoundment..
7. If composite samples are needed combine the samples for
each section and mix them well to form a homogeneous
composite sample. Do not, however, combine samples
from different sections.
WDRi 96/029
D -

Acrer.cix C
The sources of ex;s::ng environmental standards, criteria,
anc 9u1dar.ce will be presented in this appendix. Criteria
used to evaluate the clean closure of hazardous waste
surface impoundments will be presented first. These cri-
teria are Agency-established exposure limits and include
reference doses and carcinogenic potency factors. Discus-
sion of these criteria will be followed by a discussion of
existing regulatory standards and other guidance on the
levels of environmental pollutants.
Reference Dose (RfD) refers to EPA's new terminology for the
Acceptable Daily Intake (ADD . The RfD is irerely an
esti-ate of daily exposure to the human population which
wou-- appear not to present an appreciable risk of
deleterious r.oncarcinogemc effects over a lifetime of
exposure. The reference dose is expressed in mg/kg/day
whereby the no-observed-adverse-effect-level (NOAEL) or
no-observed-effect-level (NOEL) is divided by an uncertainty
factor to reflect the quality and type of data.
For potential carcinogens, risks are estimated as
probabilities. The carcinogenic potency factor, which is an
upper 95 percent confidence limit on the probability of
response per unit intake of a chemical over a lifetime
(i.e., only 5 percent chance that the probability of
response could be greater than the estimated value on the
basis cf tr.e experimental data used) , converts estimated
intakes directly to incremental risk.
The carcinogenic potency factor is the upper-bound slope
value based on the linearized multi-state model. It is
expressed as (mg/Kg/day)~ . The incremental lifetime cancer
r:sk can then be derived by multiplying this value by the
intake concentration (mg/Kg/day). The cancer potency factor
differs for the routes of exposure (oral versus inhalation)
to reflect the varying dose/response. The cancer potency
factor is determined from animal or human experiments where
the excess cancer risk rate is calculated for a lifetime
experience (i.e., 2 x 10" per mg/kg/day).

Predicted risk may overestimate the actual risk at a site.
However, this method is used so that carcir.ocer.ic risk will
r.ot be underestimated.
Natic.-.al Primary Drinking Water Standards: Maximum
Cont&minar.c Levels (MCLs) and Recommended Maximum
Contaminant Levels (RMCLs)
Drinking water standards under the Safe Drinking Water Act
are promulgated as maximum contaminant levels (MCLs). MCLs
are currently available for 16 specific chemicals
(10 inorganics and 6 organic pesticides), total
trihalomethanes (covers 4 chemicals), certain radionuclides,
and microorganisms. An MCL for a toxic chemical is based in
part on the allowable lifetime exposure to the contaminant
for a 70 kg adult who is assumed to ingest two liters of
water per day. Total environmental exposure of a particular
cor.tamj.nant from various sources was considered in calcula-
ting specific MCLs. EPA estimated the amount of the sub-
stance to which the average person is likely to be exposed
from all sources (e.g., air, food, water) and then deter-
mined the fraction of the total intake resulting from
drinking water ingestion. Lifetime exposure limits were set
at the lowest practical level to minimize the amount of con-
tamination ingested from water, especially when exposure
from other sources is large. The MCL calculation is
_d]u5ted by an exposure factor to reflect bodily absorption
associated with water consumption.
In addition to health factors, an MCL is required by law to
reflect the technological and economic feasibility of
rer-.ovmg the contaminant from the water supply. The limit
set must be feasible given the best available technology and
treatment techniques. A safety factor is included in each
cf the standards to provide adequate protection for more
sensitive populations such as infants and children. Safety
factors vary from chemical to chemical because of the
different risks associated with each.
Congress recently passed the Safe Drinking Water Act
Amendments of 1986 which require EPA to set standards for
more than 80 specific contaminants by 1989 and for 25 more
every 3 years thereafter.
EPA is now in the process of developing maximum contaminant
level goals (MCLGs), which are entirely health-based, to
serve as guidance for establishing drinking water MCLs.
MCLGs are classified differently, as "other criteria to be
considered," at Superfund sites. EPA recently promulgated
MCLGs for eight volatile organic chemicals (40 CFR141.S0; 50
Federal Register 46380-46901, November 13, 19851 and

proposed MCLGs for a larger group cf synthetic cr^ar.ic
chemicals, inorganic chemicals, and r.icroorganis.Ts (5;
Federal Register 46 9 3S- a "designated use" tor usesl, which considers
the water body's use and value for public water supplies,
propagation of fish, shellfish, and wildlife, recreational
purposes, navigation, and agriculture, industrial, and other
purposes; and (2) "criteria," which are numerical limits or
narrative statements necessary to protect the designated

States rust az.zz appropriate water quality criteria
sufficiently stringent to protect the designated uses.
Numerical criteria must be based cn ancient water quality
criteria recommendations published by £?a or developed by
ether scientifically defensible methods. States -ay also
ir.odifv EPA's recommended criteria to reflect local environ-
mental conditions and human exposure patterns before
incorporation into water quality standards. Guidelines for
deriving human health based water quality criteria were
published on November 28, 1980 {EPA, l->80) .
Federal Ambient Water Quality Criteria
Federal ambient water quality criteria for the protection of
human health have been developed for 62 out of 65 classes to
toxic pollutants (a total of 95 individual chemicals have
numerical health criteria). The health criterion is an
estimate of the ambient surface water concentration that
will not result in adverse health effects in humans. In the
case of suspect or proven carcinogens, concentrations
associated with a range of incremental cancer risks are
provided to supplement a criterion of zero. The Federal
criteria are noner.forceabie guidelines, which many states
have used in the development of enforceable ambient water
quality standards.
For most chemicals, federal water quality criteria to
protect human health are available for two different
exposure pathways. One criterion is based on lifetime
ingestion of both drinking water and aquatic organisms, and
the other is based on lifetime ingestion of aquatic
organisms alone. The calculations incorporate the
assumption that a 70-kilogram adult consumes 2 liters of
water and/or 6.5 grams of aquatic organisms daily for a
70-year lifetime. Of course, calculations can be made to
derive an adjusted criterion for drinking water ingestion
only, based on the two published criteria and the same
intake assumptions. These ad]usted criteria are.more
appropriate than nonad]usted criteria for facilities with
contamination of potential groundwater sources of drinking
water because they are based on more realistic exposure
assumptions (i.e., exclusion of aquatic organis- ingestion
as an exposure pathway).

Appendix D
WDR25 2/011

liipl«mb«r 24, 1116
Part IV
Protection Agency
Ould«Hn«« lof tf>t Ht»Hh Rl»k
Au4um«nt of Chtmlc*! Ulxtur*!

tuiiwi f Vet It Ho tta I	jg^raW U 'M f V&xn
OrvwxMEjrrii wcTtcro*

¦i 1 r» L'S fonaaeii/Avwes
AjiPic^ fEPAl
MW IVm. Ctudi'-* m to h Hiili
Hial Aimium ri Qruul Hdim
TtuUl LioWtniil
fHiKtieg AftnCf la todtr Utuiftt
fUidtliftti for titewinf lit b**lLh nail
tf layuvfuncnulyolluitsii Ti*n krr-
Cfitdifmn fv Ctimiifi fc*k
Cmdtbn*) for EiliaiUfl Kcporjiw
Cw^iIlam fof MuHfMuai) ILtfc
Cuidiitfr* far lit Httltft musni of
Soiptct Daxlopminlal ToucUU
CuidtliJvtt (or « Cwdt!ift*i for lb* H*| 'si JUah
A*»*uieni c£ Cb*uuLMi«curt*
[trn^ii "Cjifr-.ri I trr «cbM U
^.di Kp-fl u ji* :J EitnitK
rr'i'jg ¦: ha u iFkj d
dlfCUUl SL1'*TH IS Itflt Witt 0W~
pcbcxi tnd ptocrdirn	li
At iit'uitt «^ \h« tPK
Thtit Cuidiii&M %it di^lepa^ I*
ptr. at u sirftn fifekntt
pnpa viii iba
• uJTiuii el vkt Offitt of	md
Ermvcaoituti Am>w» |,Ot"QLA| ¦
ibt A|t:e) t OCa «l Mvck u4
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ceni dini BL el public u< ScirOOl
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frot»Md Gujdthnti tor lb*	Ibik
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Tsui py-b.iu.-bn uraiInin u« L-rs
*e*d a:'r.M iiMUMB-fjtdiLiPn
4nn o;ierri	imdtLjHi viLba
»du* juddiluwi anLbm
4t*ilep*d «i i^ivpniu.
vmrni l»tlTil CwAtUaa* «U1 W
lfl«en»t Wptntor U ll|i
Vi/t«rM iiW A*"< li ll^ fcok. tha
KA5	kfcn
nfhUun ^DC n itubJ*ib *M	
v rvwv «wwy tai
nduucxl iwd/iy » n*k hmumiii
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Tk« (MidtllsM pftliitod taiif ¦«
fnrfuru *f 4 m-f «w Ajcuytridt
lAark U»	AM7
KXTdiU frw lb* Urpr K rrbflc
amauRj^ TkM |w6»Umi m IsA
ftuaplvi knd pvctdnrw * pad* OA
toniiiu la tW cortduA ina^
Gi«r-b7-CJ.M iMkil y|rv4 Hill
eefwidcnsw le ill ifltrui ataoAt
teiernjuon. TV* C4w-br<««*
miai lb n Atney ti^rrvi rrrhv* te
•cMnaAc	m tick if«at iad
am tii mot: aa^ntiftullr
fcwrpp*u.UB* »ttMti ruk TW
fu«4eLri( ti*e «Hi av' Ifeit
it'mjif • £ h hif jwinfri b
-Hfi B n- M L I«11* 13 = -i»CiS**-U uti
&*i A^utrjr	v^T vimsfy tbr
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d*v?h&( narutrin.
II— T.-~-~ 4J^ WlCOBJ. M «*U M
At	ud nuoMli br
«*ci Huiani
ro*U).'te fudiunM in r««uU»d
k p*n 10 bnd«i Hp* la r*A wmwi
•eitofctep ird diu ty tJnt/jvf
*»h |i^* ird'l^ iaptnum »f ii*
uttff ui/emjb»r i» Om nth
itMunw pw»i CPA witai If
muwip mat^h urf uulrMi tk«t
«nil it id te *r> i^k tt
Wtiidi ud iim
CididM^i	l*k,
& PutMrt K«nib«ft Mt-^odl
l>ilmvan tni Orvtl0pa«n! fuBL
tnw«W(Mil Cnitfu uvd Atwtnnt
Offiu U S ExtimMnm fKiidw
Afrxr* M w CUjt (>t«V
Cmnsaaa DK iMpin*. KimM la tm
n*14i •( laiiulpjor phtnnicaiMUa.
tnd irMpt indtMfit.kW.
«nd 6Ui«- (ninuMvil kttno«. ffcrf
¦ hi tMh rnmitd !«• pvbUc anNM
iB ut to«j ti»w [» rt UTCKX
fknrrbrr I IN* KrAlnuiwiM
diracwtf	idUM «m *«
fupawd rvi^ctnn * pi^e^Al Wi
Mmii Bin^ untii flju! |ut«*un«
AH*f &" ib* «t At pvbbt MVMISl
pvnod Ajtnfy iidt p-fptnd
Tin-""* a/OBrnffiiDU tntljrM* at
««iar imwm	br ifi*
ud ffilauM') Aftney
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Itoi T%a Ul awiAii *ip«
auoooad va thi FadinJ Lrfinw at
feUowa Fthrun tl ittl iiO FH ttll]
*m4 A#rtl i. UU1U T% 1HJS ud
h i lrn«r h Ac JUauiinw4tt«rf
|hh U> "us. tb« l*«c«^tCeiUii(n
tnmllr «oncwT»d M til flra af Iha
pudaliMt. but neee»«ded*rtiha
itvlaieu- and faquMtcd tfttc uij
i«vi##d pudikMt ba tubunad t» th«
IfftlflMII &AI HW* flMl Ihiimtt
br i*r»r" uf annnvarw b*S«l/ «l
hi ExtAi^tCMWKtM u"Jb U Jkii*w=«:i ii t^iT-od
Kutwii %it« itteund on ir i kucr
4tvd Au(wt 11 IMS Copt** *t iKt
kntn v> t>tO«V* tt fublic
t/ormi^ot Rt'ti-.a ObL OK
Kitdqiii^cr* UbnJ7. it uidiui.rd
abr»b«rj ji ifcjt laiiea
fc UT^a^ vbi ^r»»bl» u» hri p«i^a:
h/i A eenttiAt ihi C«u4iltna« and Nd
E ifci Ritponx <• Kbltc wd
taiMt	Sttrd Cawntnu ft
f Lr"-*Tr if tfct uiw put lit auinti
|a8 ceHipiBU ud Aftncj niponut
IB Ami coBStnn)
f&t 3\t mi/nt*4 lH» Agrntr
4*rl K | IKV.IUI I Jep*Ki Ul id trr II rd
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Bicisai gf tfui. tht SAB (MUitnitd
fc*i pwym it iep«u| n»k
UMtmtniwUl^i nfl,wl,fl?
dip*nd»t ifMi prafrrM ib lb* Mutter
ti mi*r%nons
Ajvfier h«»*
*m an i)m wchmcjl tuppvn document
•>4 «t«et ii ia b* nmpltttd br tarty
MP rW	* can army is ttvdy
njk imuikii lajhiii rtnrd a if>«
1-^-1	nrt u>i *J. rrr.m dim
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14911	FodanJ lofia'ar I Vol It No tU / Wtdanday Sapitabtr 24 19S6 I Voooi
bfmmw m
I	m bia< ¦ data ¦ ii
¦UIM *( OfCl«
0	m h*M4 m da la aa •
mJfititnU) nm.li/ abirwa-
IB Q^in,auQ»« iimcoM af Mpanu
an *«ll
tv n» nauatba* af addftvtry i* MRhtd
WW m *« mw *f ifca tokJit tffacu aad
m *• atabar	wound*
V An utva^M af addiont> caanat ba
llU M tuaailiaO** nat wmmi
au to aan4«cia4
HmltA tficm bftmmitm
A. faa* itnpeUuaa# an
Mii t«3*>eli*o«u in
rvtuirtd Tor »«u if»cu itJaTviise m
At bj'tn iri >u coapoo*-u » th*
pvcludat I tuioauim nat
turn*/* tf'omci/*?
\ Morgitnai tftfciwjbM rth^ ilaat ar *
•BKbtMaon w.il aadtUrc tafamanoe it
•ufiotnt u *ecMn ckinniMi tuui
\» ibt Mii*wt m ii» compendia.
1	WodllJVJ VA/9"Mli0fl ¦ infficiani M
nttonabi» tfttrtctrmt ku^u iiftawi ia
lfc« Bunm m m campettnu
1 t*peawv Mtimtiti for m OTfMii
an UcLai worum ar *¦*•»«
IrJenMtiN m haiim ifTvcu at
aw«nna»»nial cftrmiivy M0Mi th*i thif
bmiirm it net Uk• ly la MtoiMiuUf iflcci
l>« ntk t*«Min«nL
4 Not ill	m biii«« kin
W*t i4«fttili*4 tr k»«lt *( iifMni «f»
tftff^iui m «intbii lAfom«a wt
lit ifffcu m fnmfvtuntniil	m
•01 ••ITiciret i« iinh M »fT»c M (la
britman an i*t nu mmwiii
• T>« av*ilibit iipnun tnlomitian m
kwuftiuani far ea«4»cun| 1 na^ aaaaaaaa«L
'hinto hmm*m «T arfBani illti'H
(Mxn ^ *•* tai MtJuaLM Im aMUTii;
' b«yiW	• C«'at<<«n lm ti mm
aO«mt<>«> w Wmrnuai im«i itaiM
amd xumumi ia> rM<"r •< itfwwv a*w
lOtu AvtiJabla ae tuallv Wixtww
tf lb« n*k aiMMBtnt it ba*H m
dau frwa 1 iin|l« ouiiun thai m iuw««
te ba f«nvT«tad with »«/y\ng
componsona dtp«ndin| m sat or
diffitni tmjioen aourcti than ih#
eonAdtnai m vbf tpplieability of th«
ditt 19 1 rfik tmiifflfni tl«o U
dJsunnKtd Thit un ba offitt to mci
4rfy* it data in available on w»*rmJ
¦j 1 rural of Oka tui eompcnaati thai
k*v« difftrtflt eefflpoatni rttioo wKjth
oncoapau ifca ttmpor*J oraoouol
diffirancai te eompontioe 01 tKo
•ixiwt of c«ne«m. 1/ avct dita tit
ovaiiabla 4n attampi abould ba udo t*
dttamma if iijmJlcant and avitaroue
dlfTarancai auat anoni tha cntmicol
¦ujrum. 1/ itfruficini djfTirmcai art
teitd rvi|ti of ruk tin bo aatiaaiad
iMMd on ih« tosjcoloftc data of tho
*inou» Autuni If bo aignificool
diffrveooa n ooiad vhio a 11/14!* ruk
UMiiaaot nay ba «d#quata alkbou^h
(ba rtn|r of nuei of tha eempenaeu >a
tfc* naiwti to *bje> ^1 nafc
uttumant appliai ihould fclio ba pvra.
1/ 60 data ara availabla on tho
axixrum of wnera. but baalih afftcu
dau an availablt on a ittiiiai onrurt
(La. a auiun it W14 tht iama
cesponanu but is olightly difftrant
rtUoa or haw\| iavara! tomnoo
oonpentnu bui laekinj on* ot mora
ocmpon*nti or hiv\r\j on* or mora
addi'jenal componcnu) a d*cnieo suit
ba m« it whc.Sfr tht aufun on «beh
b*a!th ilcti daia an a^ai'iblr 11 or t*
aot' ioffia«nil> itmiltr" to th« natura
of concant to panoit a nik aiitnatnL
Tht dinrmifuiion of "awfTioant
amilanty" Butt ba Bad* oa • eaia-bjr-
com bona, eoniidfnni not onJy tho
uc«rtaL£3*i aiiociatad with win| data
ae a diniaJar antun but alio lha
inc4naipiiai of uitai othtr approach*!
auch ai additivity In d*t*nninin|
raaaoiubl* iiaulanry eonaidaranon
ahould bo fi*»n <0 any tA/oratanoa oa
(hi rc3ipon»rti that djfTor or aro
eoniamad ik sariadly difftrani
proportioni b*«warn tht anturt on
•rhich htalth cffacta data an availablo
and tha vuxiun of eone*m Nnieuitf
ovtphaoo ihould b« placod on any
toucol»fie or phamacolunttie data oa
tit* compontnu or tha mutuni ahidl
would bi uoful in ai**i*jn| tho
tiftifiunc* of any ehimjcal &fTtr*nca
b*iw**n tht iisular ouitw* and tht
am turn of co pic* m.
Cvtn if a nik aiattimtnt tan bo *iada
aimi data on th« Biituni of mum or
0 naionably umilar mmwt it stay bo
dturabl* to conduct 0 nik aiMiimtnt
6«wd on toticiry dii« oft tht
conpontnu m th* oiittura uoinf tKo
procadu/a owiiintd ib taction U1 In th*
cih of a Bisturt tontiLP.;n| carr-.ro|i*j
tad toaicanta u approach bii«d on tr.a
¦utj/a dau aloe* say not b«
tiJT\utntly proiaca** it all uki For
oaampl* thu approach for 0 '"o-
arapontm Bjirun of ent tart.roirn
and ona taucam would uit lonci'.y
da' a ob tht Burura of tho two
oompoundi Kowtvvr Id a chronic atudy
of tveh a BJirurt tha pnnnt* of tht
taiieant could naik tht oc'jv-.ty of tht
caronoftr. That it to toy at doatt of
At Butui* tuiTiciint to induct 0
uronofinlc tflacL tht toucan could
laduct monality ao that at tht maxunum
taltratod dew of tht Bithm. no
cam/ioftruc tfftci could bo obitntd
(met caronoftmcity ia conaid*r*d by
tht Aftney to ba a nontAnihold tfftci.
It Bay aot b« ptMdtnt to conitrut tht
aaittivt muJti of tweh a bioauay aa
tadicaunt tht tbaanca of nik at lowar
doiti Conttqutnily thtitintkra
opproteh ibouJd bo BodJi*d to allow
tht nik antaior to waluatt th*
fottniiai for atikjni of on* *ff*ct by
anothir oa a un by-UM baita
C Oata Availablo Only on Miarura
If data art not aiailablt on an
Idtntical or nnoatbly aunilar mixturt.
tht nik aiMiiffitnt ouy bt btitd on
th* totic or tircinofrnie proptniti of
th* wmpontnti it ih* mutur* Mhtn
bitJt or no quanutauvt mfontation it
•vailablt on tht pottntitl initraction
tbo 14 tht corponrr.tt add t"t nodt'i
(dtfintd tft th* ncit it:*ion', an
neommendtd for tytttmc totictnta
S***nl ituditi ha%* dtmomtrntd that
dott additiv• modtli ofttn prvdict
naionabl) »*ll tht toxicitui of
Bjtrurtt compoitd of 0 bubitantial
rtnt'y of both umiUr and dunmilar
eompoundi (Pouanitt al 1IJ» Smyth
ot al 1tM :t"» Mvjph> I MCI Tht
probltm of mulnplt toncam **?oiun
hn bttn tddrtittd by tht Amtncan
Conftrtnct of Govcnmcntal Indbitr.al
Hy|'*nim IACC1H 1M11 tho
Occupational Safri) and Hta'th
Adrmntitration (OSHA 1M11 tht World
Ktilth Or^tnitation (WHO INil and
th* S'ttiontl Rtitarth Council [SKC.
IMOa bt Ajthou|h th* focut and
^urvoit ef ttch jroyp waa tomr«hat
difftnnt. all poupi that ncommtndtd
an approach tltcitd to adopt tomt t>p*
of doit additivt nodtl Nonnhtltai at
diicuiitd in ttction IV. dctr additivt
atodtli art not tht men biolofically
pliunblt approach if tht compound* do
not havt tht itm* mod* of tOKicolofic
action Conitqutntl) d*pandm| on iht
ntturt of iht nik aiitiimtni and ih*
available infommon on modti of
action and pautnti of romi action tht

rWtrtl Itflittr { Vol 11 No 115 / Wttfnndav Cp'-tninr 14 1«U / Nelien
•on maoaablt additivt Bodtl ihowld
bt aatd
1 Sfutrmc TatiooflU For tyittmle
•oucjnn tht tuntii mi atattamrnt
»*ihodo1of> mt d by tht A^«ncy for
am((t eompeundi boh ofitn rvtu'd In
tha tfrnviuon of an npoiur* 1***1
which ii not anncipa'td to emu
aifmficam tdvcw tfTicti Dtpvndiitg
on (At ffovd of ttpoiurt mrdu af
ocncrrn and iht tofuliiivt randait
fuidmi tht ml aiwumtnu. thtat
aipoaurt Itttlt mty ba iipniir^ (it a
•antry ofwtyi tueh n aootptabla daily
teukti jAfiUj or raftrtnc* 4mm
(FfDil fcrvtli aitocmtd with vanoat
•ir^ini of aaftiy [M05I orteetptabla
coneani/aocn* In »ano«# mtdn Forth*
pvpoat of thu ducuinon Iht ttrw
*a«apiabit Itvtl' (AI) »ilJ bt «atd to
tadicatt any itich ennna or adviionaa
dtnvtd by tht Afrnc) U*tlt of
tipeiun (tl mil bt titimiiti obtalfttd
/oi;o*ifl4 iht smi eunrni A|*nry
Cuidt'jnn for btLiMiinj Ctpotwm
(U5 E7A. laa&ij For tueh Ytumiift.
tht 'Uuil indu (HI) of a Bitrun
ha ltd or. Lh# aatumption of doot
add.i>on Bay bt dtfntd ai
IL»*Tvann"lr*tl ts tN ^ tatlctM* and
Al,aMLBu Morpublt total tm tht f*
tinea tht aiiumptiBD of doM addition la
bm' prcpf) appl>*d  auility of tht
aipmminul mdrne* rjpporun| iha
atiumption of doit addjuoe «uat be
elttHy inieiitlttd
Tht hturd indtt prvrtdw • rvu|h
Miiun of hktly loticity and iv^uini
cawiiovj mitfptiiiion Pit baurd
bidti ti only a tunmul n4icauon of
tht fltimtii ie icctpublt liaiu of
•ipoaurt or Iht itftt u wlueh
' tm »>	• p tl' I»| on Pa MBM)
tv aUar«*M m arm ¦ anm* m km
Mstpublt aspooun art
nettlid Ai thii tadti approachtt
«!•> concarr. for Iht pcitntial b»«rd
«t tht fturun wotittt U tht Indti
ettndi unify tht oonccn it tht aarna
u if an individual chfarncil tipoiun
ncardtd iu aesapiablt kval by (hi
Mm* proportion Hit baurd indtt dota
Mt da Tint doM-mpoftat rvlitionahipi.
and itt duffitnca/ tafua thowfd not bi
•onitrvad to ba a dirtci Mtimi it of ruL
Nonaihalrtt If aufFictttit data ar«
a»iilablt to d«n«t tndjvtduil
•eccpitbla lavali for a apaemtm of
•fit cti it |. MFO induetiofw ainiaal
afTtcn In at^tral orfina rtprodwciur*
•fTacit and bahavioral afltcu) tha
kturd indti rty iw^trtt trhai fyprt a#
afTftii «i|Si ba aipaettd from tht
ntrwv txporunt it Iht toaipontnit'
varnbUiiiti of tht accaptablt kvala in
Lnown it J tht aceapiablt kvala art
f »tn at ranftt (t | aitocnttd with
di/ftrtnt na^ina of aaftty) than tha
kaurd mdtt thowld bt pmtntad with
eomipondiat nu&airt of ranauoa er
Moat arvdiat an rpfrr.ic leiidfy
ivpon orJy dttenpuona of tha afTocta la
aachdoM^Vtfp Ifdott-ratponaa
curvai art aitinattd for tyiitmic
toucamt howtvtr dott adin*t or
mponi»-add.tivt attuopuoaa can ba
M«(f wi'ii prtftrvnea f*rn to tht Batt
biolof cilly plauiiblt aaiujripnor (aaa
aaciion IV for tht rathtstuea) dtuila}
L Cixiroft't For ea*uno|»*.»
whtnt«tr Unta"> of the ind<*idwt!
dott-mponat nnti bai bm asiuetd
(utually nuncttd to low dotti] iht
tneniit it nik P (alao calltd ateati or
tnomtnial nik | ca ua Ik aa.
r*d» co-si
For aultipla aovipvund^ &ta o^aittoo
¦i) ba itnanlitad u.
r-S4ik (0-t)
Tbn aquation aaauari tndtpmdtttct of
acuon by iht aavaril UTio^ftna and la
•qu.viltni to tht anusption of doit
addition ai wtll ai to raaponaa addiuoti
wi camplttaly ntfatita urralauon of
tslaranca u lorvg ai P < 1 (m aacban
TV) Analojoui to tht praetdun uatd Ift
•Citation LM for tyiitmit toucanta. aa
todti for a eamnoftna eaa ba
dtvaloptd by dmdlnf aspoaun Imli
(I] by dom fD*) aaaouatad with a aat
lavtl of nak
Neit that tha I*m tinoar tha doat-
mponM eurvt ta tha Ian tpptwprtatt
aquauoni 0-1 and U-« will bt parhapa
*vpn at low dotti h ihould bt
amphaidtd that bacauH of tht
¦DcanatBUti ta aausiauni doit-
loaponat rvtabonihipt for im|lt
•ompoundi aad th< additional
Mcanataiiti ta aoetbui^ (ha
hdividMt aausau w antii rviponaa
froa txpoaun to aururta mpsnat
n o uvd bu*rd laditn a*> ht*« Bent
h tospanAC niha bwt ahould net ba
ftftrdtd ai auwm of abiolwit nak.
• fni*r*cl>oni Nona of tht abova
•quabont lacorporaiai any lanr of
aynarpitic or umgotuiue inttraetisa
Sent tjrptt of tit/orvtation howt>ar.
•ay ba avaJabla that lunttt that two
or boiv oompontnu in iht eiaiuft miy
toiarocl Swfih ta/ormation suit bt
aaaatttd In lama of boih iu rtltvanot
to aubchmuc at c^rvnic baufd and iu
a^ttab Jify for i**nuuu*ilf tlitnni (At
flak iaataiaitai
fortuaplt tfcfcmjc at avbck.-.me
torJctiy or wrtiMttmaty aiudiai ka«a
batn oonduetad Ihat prrmn a
fuantiiativa atumation of mtaraettoti tor
fwo ehnalcaia thn It may bt dtunbla
la CBAiidtr aaiai t^oattona dttailtd m
aocuon TV. or •odficauona of thtit
oqwuona. to e«at tht two compounda
aa a alafJt losi&ut witi ^tntr or
Imtr poimry thar would bt prtdieiad
froBtddJB*ni> Otharoovpeotnta af
tht •jtmn at wbch ao iwch
laiarceuoo dau tn aratltblc aould
thae ba arp*ntaly tvatad in an additivt
•aantr Stfopt tueh t procaduft ta
adopted, bowtvtr a diicuaaion ahould
bt pmantad of tht UtUhaod thai oiHrr
ooepouadi in thi Bitnm ray Inttrftrt
with tht tatrtenoc of tht rwo loticant*
an which quvjtativt tnttraction daia
anavulablt U iht wti|hiolawdfnrt"
piiUini that initiftrvaca w likily than
a Qvanuatira alitrattan of tht nak
aaatiaatni tiiy aot bt fuabfitd Ir ivch
¦mi tht nik aaatumtni Biy only
to6catt tht liitly aamn of mtarvenona.
ritAtr tyttrrfttbe or tfiitforutue. and
•oi tuuitify tb»i/»vp.iigdti
Othtr rjrpn of tn/orviaiion twefc a*
thoaa rtlauni to atchamiBa of toncant
tmtfacbOA. or fuantKauvt fitunatai ol
tnttraeboa barwtan two chtmiula
dtnvad frra aevtt amdit* ani r»an Itia
khtly ta bt of ui lit the Qwantnttift
atMatarni of loni tam haalth mka
Uiually It will bt appfopnatt only to
diteuai thatt typti of information,
tndicait tht filtvtaot of tht information
to fvbekrerue ar dmnlc atpoturv and
Indicatt tf potiiblt tht aatun at
peitntiat tftttftniooi wtihowt
antmporvi to quantify thair Bafnitudtt
When Iht tntrrteuaaa art tiptdtd >o
ha*a a airvot lftfl«rr»st rr tht tiiiturt •
toucity tht aiMiiatnt ahow'd ind'eait.
whto poanbtt tht eompoundi boh
mpeniibJt for tht pftdictad toiicny
T\n tudrntm iheuJd bt bt»td an
prtdJctad lawaty af aach coapontni

MOI	r«*r»l Ulster / VoL II. No. US / Wadaudty UpUxtut U 1M» / Nobcaa
batod m atpom and usic ar
cwof«i^( potential nil pattnttal
aJont iboJd oo< ba vrf u u tadicatar
•f Ae *««(»(• pmnj At «oti luwl
4	For udi flak
•Mwmcni tha mmiktsn ihovld bt
cJta^y A»«md and fta o**nlt qualify
•f to nak mnprnwt ihould bt
c^artc^traatf T\< adttM tvtbaod to
Tab)* J Awild ba wd ia upnw tha
daytt of ODriTidarwa to tha **ialny of
lha data m aimcooa. baaltk offacta.
aad npoaun.
• Haalth Lfftcta—4n mm cam.
%b»n baaltk tflKTi data tn toooaplttt.
tt«4| bt pomibU <« arpfbr a«u/ofy
m Quaneuova i Breton-activity
Mauonj^ip* th*i Um ompotind* •
*rhith m bailih tfKu dau an
a*ail«bia an wo* Uktly la «*ruflcantJy
affaci ifca tcuciry of ibt aiirun V a
mk iimii "»«ni mdudat rvci u
«nru»ceL liM.ut9n» tt tha
appro*^ n*r ba dauHy aruculatad.
(>n i a*thodoloQ bai ul
adopud for arbaaoni u amp tibia
lavtl (i %. ADI) v c*mcof*ojt
pcttntiaJ-foc nnjj« ocmywawU baaad
tiibrr oa q\i«aoiatnn lOMctva-anvity
nil isnhjpt or oe tht rwuJu of ahorl*
term »a-r»rw\( taau. tuck aatkod* an
*o< at	ncoaaaeda4 ai tka tola
kuu of a rut imi—runt oa cfeaaicAJ
b Lipoaun UnorrUiatia*—Tlia
paeanl nctruistioa is ttpatun
umuvti btvt bun %6irm*+4 ue tba
Af«nc> 1	fx ti'o&auai
Li^cxutm \\JS D»A. 19B6d). Tha ruk
Mwiw liouJd dticuu \Stm lipoid
Bwanatflba* ib urma of lha itnn|ib ai
tha	uaad le quubfy At
atpoaun Wfcan appropnaia. At
ajMuor ibould al*o coapan
•oojiar^n md •oba'.ir^ 4* la ted
4i*cuaa aojr tacouuianciaa u a aauraa
or unc«PUirty far CL-iiw«t. \kr*»
uuruitLfi nar ba issvaaad ai tha
kuabar W foajnxrwla *i couwn
If lavtU of iipoaun W acnala
oonpouodi know la ba to U« autun
an no 1 availibla bat laformatton m
kaa'tb iffttu tod nrtraaMitu!
ptnmtaci aad 9wup*n	tkat
eoaapouada an aot liktly U ba
ai^rufiCAiii lb iJTacuni lha Uboty af tka
Buttn. thrg a ntk umumt cm bo
conducted baaad «• Uu rtasMTf
compouadi is tba mijitwa anii
appropnatt cavtau U fuck u vyuacat
caooot ba luppentd m fiul nak
twrani tut bt paKorvad u«U]
adtquau •oniienni data an av&iiabla
Ai as ifftanjD proeadm • rt»k
WMrasarti »ay bt ooaduciad for Aoo*
aempeonta ta tka aumi for wKick
adequate nr^otvn «ad haaltk aflacu
Aau an a*aUabla If it* attn® nak
aaaauacnt dot« w< MPii a Uurl
Aan la atlC aenean atom tka flak fraa
auck a aistun booauaa Mt all
erapooma la Aa auiun ka*t bra
t UuuuitiNi la|Ardi«c
Canpca»lrfa *f iki Mtiiun . to poi^ipa
a «ont cam acnano. w/ornjoor say
ba laciuai aot mtj ae badtk affacu aad
k*ala of tapoaun bwiaiaeaaiha
Idaatitr t! toa* eaa^owflta af lha
Kuturt AaaJcfoua to tbf prwaduff
<»Krb» r a turn of tw9
aospeundi »it tatttd oftan ia otJy •
aLr^lt ooabinjiiofv VUjoi an 11 of
unctnainty wife lha ua af uicb data
ln*olva iki apprapnatanaai of
tnitracuoo dau troa tA acwtt lasidty
arudjr for ivaootauval) a!iann< a nak
aiMtimrnt for twbeh/emc ar eJtPoait
aipoaun. ik« apprapnatanoat of
initnruon data an n»e eespontnl
*iniuni for quanoiativaly aliana# a
mJt inaaaaant on a ouxiun af aavaral
compowida. afid lha aocuney af
iBtanetwa data an aiparuntntal
«iuma!i for fttanbu&rrJy ff*dicUA|
loWraeUorva «n huwana.
TT\» u»t af Irtvnctton dM fnm anta
terioty ttvdiai to ataaai tka yottrtnal
Inttraeoont on chrotuc rrperon la
k|hly quntionabla inlaw tha
¦achanjim(t] of tka tatmctton m ae«ia
aipeaun van known 11 apply 10 bw>
doa« Annie acpoiura Montnow
bielof cal mtchiruaai far toucant
Latarvctooa bowavar. Involvt a«*a
font of uapauuoa banroae tba
cktucala or ptaaotMoa isvalnag
aanmuoe af a ncapiar aita at Miabebc
pathway Ai tka daaat of tka Uvcuu
an dacrtaitd. It u Ukaly that Uaaa
•tcitaniiaa at^ar m lafitar «U1 taan a
aifruficam afftn ar trill ba daoaaaad ta
aa iitaat that eaaaot ba aaaiund or
appro hLM
TV «a af ofar«aaon fr«a r»o-
aa^tii utnt 10 aaaati tha
laiarwujaa la a autm asniainini
aon dbw n»o aoapowndt alao 10
tuattioaabla fr«a a •acLa/ntiie
par»pacu»a Fariuvpla if n>a
aoap««nda an kM^n i« ifliaract aithar
•yudfiiuully or aaU|Qnjtuc«l!y.
bac4ua« of tka affacu of ona canpouad
aa ika atubohan or aienboa of lha
mbm. ifea addiuoa of a third ooapoi*rd
vbich aitbar cktaiuUy aliin or alfacu
tha abiorpuoo of ana af tka flnt two
oonpounda emli aubatantialfy altar tka
dap w of tha toueatofic uiiaraction.
tawaUy. it iblatf atwdiaa quamifyMj
toucaat launenooa an not availabla
a» aalticeapBiwBt auituni indilia
ftw atudtai that an avaJablt on auch
¦Uaruna [04. Cultino at al. IIM| da aot
pntndt a«Jfiant ut/omauon 10 aaaaaa
lha affacu of wtmetiva tntarfannca.
Concama with tha «aa of mttracnon
dau on aapanaaoiat aammali to
aiatu latonefiona ta humana 11 baiad
as tka movttiAt appnciation for
•yittaatie diffanncaa amonj ipaott in
(fiatr ntponta 10 individual chaffliula If
•ytuaauc diflanncai in tasit
aonaitmry to u|li ckairucali tint
aaon| ipaciai than 11 Kami naionabla
to tuiitit that tha aagnitudt of toaicant
inttractiona aaea| ipanai alio aay
vary la a iptamauc ainnar.
Gni*qu*fttlf tvtfl if uulbni ehromc
data in iviiablt n tha aipitudt of
toxicant Lnttracuofu is a apc:iat of
aipanatntal turiraJ. thara ia
uioanairi) (hat lha «a|rttudt of tha
Inunction »di ba (h« atria m buniiu.
A|aA data an not availabla ta proparly
anaaa tka ai^uficaMa af ihii
Laii. tt akould bt taphaaiaad that
aoaa of tha aodali for toaicant
tauraeuon cu pndict tha aafnituda of
tAiicant iBuracuona m tha abianca of
aataniiva data U aufTiciant data an
availabla 10 aitiaatt (Attraction
coafficitnti aa daa9ibod in aacnon IV.
than tha U|rutuda of tka loutani
lataracbona for vanoua propomoni of
tha laaa tamp«Btmt can bt prtdicttd.
Tlta availability af an tfttcraction ratio
(obiarvtd ntponaa dividad b> pndicud
naponatj la vaaful only tfl aaaamnc tha
of tha taucant tntaraeuon (or
tha apaofiG ffoponiona of tka antun
which wu M*td ia foearata tAa
lattncuaa nti*.
Tia U*t aattsptlon in (ht
itcommaBdad approach 11 that nab
ataaiimmta on ehtnuut miatuni an
boat conductad wtm| toiicoloftc data aa
Aa fuxtun af cenctn or a naaonably
aiaila/ auatun Wkila aufik nak

W«r»J titJitn I Vol II. Ho liS I W»dn	(abtfwBt in iptaii-
i»-ip«cj«i •ivapolation for tln|lt
•empoundt tpp'j io tuirum Wbte
Mini btalib iQteit dan on chtaiuJ
rururri from arwdiai oti aipoaad
ki^in population (At (iriiKMiu »{
tpidti&iolofic iruditi in tfea nib
taitiimant ef nr*I« cenpeundt alio
•pp'y le ffiixiurtt Additional Im ntDU
iiiy b« intend »b**i wii| htalih
afliru daia oachafiitar mrurai ifibe
wnpcninti us lb* bururt in boi
wnaitm »r if iha oompoMota pontoon
le lS4 rmronrem
1- Addifl*lty Irfodt la
If >ufTictfi< data in no' available on
thi aflteu of ib« chtmiu! Bjifwt of
cancers or • micnabl) tisular
Cfei mpoiti ippwicfc u to $nunt
eddmviiy Don addniwry u battd n
Oil anuftption tKat i>t campentnu is
tfer c.i:urt Ka*a lit MSt rod* of
tenors tnS tliciv Lhi t«mt afftcu TKjI
aiiuripiicpi wiU not held bmi It men
am $i l#i»t for rutrur™ of lyntBje
to tj earn For lyr.rmic louunii
fcswtvtr BHi compound niV
•	w^J! nets* It Oi Ih* dtnrillm
eftve;ubU Iim'j *»\ich ai runr.i!/
d*r»n«d c^twei b« aitpud to (he
diPItrtni form* of mpofto* addi jvify aa
wiaiiniru (on oustum] W boitd
•n tr mufflpuon of iddmnty, ta Ien|
•a tfi* urpenrtiu tlicit itmdtr tffnu
Dcx aifliu** and m>ou«-tddtiivt
•aaumpnonj bin Uad to lubaiammE
rrrert in rui Mit&airt U i^ffiiLic m
•ni«|omitic uiiariniona •ccuf
AJihou^ duM addiuviiyhat b**n
»Ko*-b to predict th« icuu touatio* of
•any vu&tum of tiftilw and dlMU&ilar
eoffipeund* (*4 KaaW oi aL 1»»
SnirU) ti *!. 1M ltTO Mur^hjr. JMC).
•est marked octpttofti hi*a br«n
Mtad- Fomimplt	«1 [\tn]
tMi«d Um attraction of U M>n of
fcdsJtnai c£*oju(i 6«aotf «tevtt
ltiha!i7 In nil For »ooi >•"* of
tnpettsdi t^4 ntio of iha f*iinad
U)» u obanwd U3m Aid Mt »ar» by
Mm ibaa a factor of L grtaitit
¦(»M«n »nii or oqui-voluBt
MUtfurt of sorpbolui* ud ulnmt u>
fctuci ib* ob»anr«d LOW •»» about
Bv«» nstti l*u ihiti ih* !>&¦ fr«6ci«d
^j- 6ou »44iuon Jj» * **vd>
Kaataaod at «| (l***) rvlativo rtak
«d !ua( unut aiinbtitibla to woiiaf
*aa ll. »Ua tJb« rtiaii** rtak
taiooatad vii iibntoi tipoaurt m
< Tit nfativt nai of Ttmi carcar fro®
both aaobfii and iiUiidi
»ai U pdtwwii o rvbaiaitua)
•yntrriiuc affiet Cowqutntiy ta km
«ta«i adliUnty utuBpueu uy
•ubiiarijally andiroaubatt mk la
•LN«r uui nil Bty b« ¦vartiuiuitd
».ilr Jui u eonaipj). ac unaicifretofy
liTviiuoo. ttii ivailabit dan on
fcnr anftfT/attst far uUBtunt iht
hipmjdi of ibti* rrron taMd on
tunnt ibformatiob addttivity
luuBpnoaa an tipoctad to pild
ttrttiy Mutril nh oauaam (i«.
W ihr* ooiHurvi-jvi tor kaitrnfand in
ftlatu^bla lot cottponmi w*ipaun4a tb*l
Induu iiffulir fypti of (ffacta a> ifci
tou aiiai of acuoa.
TV Mot^*r>oucef Modth wiffr*
MMturtmtnt efjemt Aetian
Tb« alspUn	eodtb for
|olsi aetoa ntu&t so hrimcboB ta
tnj-afltVii'jt*!tcntt Tb*f4tiaibt
VitAf do*« » jitkcn or r«i;>onit
idd.vjof ird it asuvi'td bj da'i «
acute lriht! tfittu of fcururti of rwe
A. Dom Aidiuo«
0o*< addition oaauaca that th<
loxicaru it a bumr bahavt ai tf ifcry
9tft d<)uboM or eoncannnona of tacb
oihti Olui vita ova ilcpoi of tht doao-
mpofM cuvti lot individual
oocpoun^t tn idinuul andM
m^ena* «boud fry utmrt unfco
frttfiettrf by atiostftf (it Utdtndutl
doitt after aiiuitiM for difTtrmcva in
la dafmad ai 0>t nQo of
•quiiotic doata ProbunnaforwauoD
typically ftakai ihli ntjo odtuUJM at *D
dotal wHan	ivn|ht Limi an
abtaintd Ailbetifh tbi* aaauBpiioa ear
ha appiird to anr aodti {a | tbacna-Ut
•oda) ui NXC IMOb). ii bai boon noot
afitn uaad ui toxjeolou' «ntb l>ia )of¦
doat probu mpotiM itodtt. which will
W uoad to lUutnta 0k« aaaunpun of
dooa addition S«ippo«« that mo
tsuunu ihow tki follotnni lot dooa
fro Pi i napotiM *nt•'& "h,B *<• Y, (iha* ia
*K«i u Btuii br oqwieut <»«•; la
y m.irurt of
two ttuconu cu ka	by
T*U*lta|rZ.*»Z.] (TV^l
Tkua ilBOt p It dtfatd oa!,/!»
•duuoe rV-4 oaaenutll)r eonvina Z*
tola u> *<«ivtltnt doa* of 2. by
ftdfiuUAl for tta dJftronco in pairney
A Bert |tn»rtUnd fom ef (hit
•*«auoB for ui tuabcr of uueutt la
Y*a.*blai(r.+ 1 (*]<•»4X |IV-a|
k*0M	»(tW l"l llljIMM
¦mm fat miioiii «l
b»tS< tit* «* 4
rus tl tta a*vWa«l tmm* » kk*
A aofi dtiailrd 6tewaioo ef tba
danvatn of ib« oquationj for data
ftddjbu it fnaaatod by fianay UfH).
ft lUtpeoM AddiUaa
Tht oiliar fona of addiliviry it
nlimi to at mpsrur addition Aa
6*uM brtlin IWtl ti/i typ* of itUit
acooo aii4&«t tha' vba t%o (cueatm
tct en dLTtrt&i rvcaptor tyiiin t£d
ttat tbr oomliuan ef ta&vidua)
toltrtncn B-a> r*a|« fos eosiplataly
MfiUM (rm -l/te aampltulf ponb*t
+ KoapmM additioB tatuaoa
Ait (ba mpaui it I pn
oor.caii.-ttea of a mLXtwt of usicutii
la eompltitly dtiarustd by tht
itipor.tet ic U>« eanponoMJ and On
(Ii-wim ocrrtltbon eotfTicum TaUn|
ai lha prapanrtdi of a^injtnt
ta a Butin of n>» touc«T.ia
trfvci rrMi tcitniuslrwpuwai off,
ud lh«&
f«P.dr«ltnd*.»r.	(TV-J i
fwP.KratOAd0.cPt	tiv^i
KP..P.t\-»0ift»0	(TV-ti
f-P.*P, ir«- turret (TV^I
Mora ftntnltud saibomttical «odt)a
for Uiit fon rl |omi action ba«t boon
|>vro by Kackan tad Harvlatt ll*M)
C leimetioat
AUtflba ibo*i Mdali atiuzna rvo
totaractiooa tnd timforo do noi
Incorporait ¦aatunatnti of tynttfutic
•r tnrtfomtbc tlftc'i Formitmnng
laucani iftiaroctigni for enrurra ol two
QBffifoueda Fuvnry 11MU| propetatf (h*

Forfanl VifUtar J Vol H. No 119 i Wod*«diy Vpitn^r 14 1W f NeCui
following eoddks* d	IV.4
for to Mditai'
whan »>. b r..t» p. ud I a* drflaW ai
ba fa n ud K h At car AcjM1 of
kwnno) A patera	K
Ir&com rjri-rYtm. I oat« Sri rtJu*
tod. ci iai anufoum tac ¦ »*U» of
an ®rpnpsBd» to tarn add ban ¦» ki
oquition fV-4 Lli atbar pre pond
¦Ddificittoni of doaa idAuoe [Hawaii.
I	MB! A« fquibM aituat* • oonritanf
tnitricuoa ihmcbewt th« anttt ru|4
of properBfffii «f mdinduMl eenprnnu.
To iudubi for ivid nymffitrtc pitiaraa
of Inmnn «i 4mm obiirwd by
AJitott at ti nm DuAia (tMI)
prapoiad thi faUewtaj ao«Lfit»uo« to
•qua dob rv-e
T -11 * k let If- * ft * * r, Iff !.["~ U.
truri*nnx trv-tPi
to K|?f	dnndfd teio twq
oooponrnu. K.Upf.f,)*' tad
•* SiAa K, ud Kt aei fcj«t tha
ha* 14a. ippvtai uutur** ol
UUteru*tr- • ' «n« ftctpior iiij tad
•yniTun H tite&rr rrwp'or fit cu
ba ntamd Mat K< ud feci n««i
oqutm tV-« i*dwan u LqiuQaa
It i&cdd ba bs"H ±a ttriur a
m*ionbl« aunbti of Crpm ol
frvadaa b ibi eiaaj^w, of K h
iquiMft IV-4 or K. tnd K, to aq«»rs«
IV-10 &• loucy of Mvnl diKtraol
ooabAteou of ifea f»o eaapennu
¦	mt ba iiw^k iln| «iA ump at
Lb« toueiy cf Jit ladivtdiuJ
at&pofif eu Suiea nqulrw*
arpanattu viih Urft BuBbrn of
ttumMlt ««ci udfM kj*v
rttanc ni for 1^4 aoa' juri to d*u ha
OCVH btMIMft U4| IflMCU (• £.
firuiry in 1 or aquatic orjifljima
(DurtjA. in] ^Jh. bocauoa of tht
eoopticry of iipofuaooul dar.jn ud
th# flitd lot Lat^t ¦ Mb ban of aniaati.
ot-.tirr tqtaaea fV«# oar «^«atioe 3V-
10 hat W«n |n«rihu4 * ipplird 10
snium of ®w» tku m laxJcuu.
ModiTiubotu of mporvM-additivt
¦odtU to indu4« kBwnA«i um kavi
II	to ba«e propqaad. alont wltfc
•pprapftait diDiKa! ittu for te
¦	mann of tddionry (tmwiUc
1«U Wtbnsderf n iL imV
b it* t9id«ouola|jcbimrm.
¦	taiuttstnu d ibt itltfil tl tcuc«M
tcitractiatu. t cu ba uptwd u tb«
noe of obaennd nUOr* n*k t» nla^v*
rui tnntc»< ua> FcfV of
«dic*if)r «1 r^epm. Aftaleieuiie *a
mio of U1IP1CM* ¦ ciUHlSAl
tm*9a0]gf} itudan. I > I todiaaiM H
CwinoBi t > 1	rrwrT**
Ud t K../CRJU (TV«U)
Aj ditouwd by both Walter and
Hol/ertf (If4| ua Jtoitau (Iff! tb«
rui-itfdj3»t eodi! ii |«n«-*il)r apvbtd
te >|tnu tititusi iwiwi »Ui ib«
aulupltcatm aadtl a aon ippnpruia
to tftnu ^ai prr*tai duiiH Tb«
nUu*t B«nu of t^ava ud sihar
tadicM bavi bate ihi rubi«ct af
eeuid«rib[( diicuiitaaia At
rpirira*raruj ihj< Tor rubb( htallb
«OBorroj irgL-dAf eauM^va [tirdc)
44*£U. addiQvt B&dil li Bora
¦oil tta tddeva and aultlptlcatlTa
bo^iLi aiioffv* itatiibuJ irdrpandanoa
le A< n«k titoat ltd trpotiei
10 both coBpoundj Is eoabiAiem cu
bo prvdlriaj bjr tbi rult itioeiaitd
aapanti tr^oaunt ie tba tadivtdual
aeapounda A* iil j»ctiad by
braittyclu u41\omai (Itni far
auleiiaft tt/eiBoftnttii At bonar
B1 Lint 1 ^0* net I Bodal anil drptnd mot
ooly upon actwl biolo^ul mtarinona.
bat al»o upon tba iu|ai oi t)i« Imim
procaiu wbieb At ooapouda tlftcL
CM>t?un\J]r Aan m w # jrwn baila
forailacaai eidMTtypo ofaodtl la •
tuk ttMuani Aj ditcuaatd by fi«ra
otai (i*l| Aaemcfyuef aiJijatafo
carctsofnoiii ud tha aflaeu of
prvaotm aad oocafonofaaa oe nak ai*
a»vratl]r coeplai Uiun AJOtoittfc ruk
aodali for pranonn h.i*a ban
propoaid (a t ^na ft *L IMit m
aso^la ippw^ cu bt newauudad it
ibf &M'
ACC1X IAmm Cmfwmm af
GOTWufcffHti Mki'rulHrV«d«til
TLV« iMUtf Liaic Mlwai lar *mial
aaXwawi ud phynuJ ^n* ¦ ita ««t
¦nw* *• ttnnitd ckancn lar
1H4- ®* Omm« OH| It
Aim*^ "t T ar^riL ad IS Fanw)
wn 1*a nam) aT I-
—»ffrarki Hi ami tM I-
aturluMhai MiMwtiHma
•a mm Tnal A»9l fUntvl
Km CI IW Tit «u>*) aTiMou
Ommtly *m. *trl *•»> SMI-Ill
Ini r. A Albm LAJwMr uil
Itofflt 1M1	ta mi *«*auJMitt
la fwitut Mtjuyiii Wm( *« liu
Ha ib« BM« iba «iii«i>«a peaieina
aaM. U>M HaaJtk tanaan 10300-
Ma FA- in tpam AlanuM b«a»
«U iJnVultf a mdy m
drouutaa »n4 (ami araoa wm|
Dupfin*	Tkmt tjnniaa.
N> luu	af Wr» tart Cobtfa
din iiMHilinitiw |
Suiitfl IW Aj aipaatk ta A«
•atlfiki at uwui airnngni a iha
ifuiK nevtuM Nordutp al Ua
4B AMi»«) 1-rBoaaJHB *n *9«4tit
Ttuuigo teotttf Iom 1 j Im Ttru/if
Ud KHIMk | MM)
Fto*r 01 IM TW toalyti* af OaiOT
taunwmm^faMi* Ajj A#fL
Mel aU-M.
fimn t>t *abJi a«b »i* M ii
Cjjnandfa Cm> Imia C«ahnd««
CaifcirAJLt Am* anl IM Kilnu
V-l »MARpl« »l^a 11m H kMtf
|t.m*ee'BO *J*i *i»TkvW |cha
* Jay ltd taw. tot aM t
Culliee 1 W * Jul tH t\nba«A |
Cenf «ld kt C 0 tn*. trr "T "" Ml>*lbA| u.
Ik. p 11-*
tam.LL.«M AT	fetMrtcirra
M-m ti awtwat •! * Ut u»ta
•Mi|ia baadti I5HIJ
LiMHO	tH *MMr*aii
¦	Ha*ai Aa | l#>d*a4U
Lavwa U Ifl AmmIt amm
•rd ihcum tatH HA. u>ua fcawa
aad Campaay ill p-

fidml IffJher/VeTll. No 145 I W#dflfidiv fapttmbf? 34 1»6 } Neneti
to 1MB (UMMIlfli
poirmn. lr iux aimcbM |*>M9
peU*un« to C-L Colli.
tD Mitftv 4Adt Haferuarfa Tht
prmtipirt *nd »nhodi » Mkn
mtjcDiop HflcHim T>* MttArrfanrff
tlwic Vcnh Hollin4 >iw p fl<
Ritltu I L iMf I Hnbn 1M
l nu » i> wtn *po* tfca
nJ*)isniKif h'»w imgit to* avMHiioo
mi Tnn K I CT«r.t^d Iftd A Wtlklt
IMC Contrpn tfiMrtciiM AM ]
Lpidisi o. 11 Jm «"-«'*?
tfT.,«irci. J >ff< D C ffwi« 11
fcc'ai>eji aMiii tad mimical
fc HJ. C-l w.J t-l Wot and CP
C«>rMr las Aa ai»l«r«Lion af pint
tvtit icvnr I t»rr r> rwr. indui7 iftui	ii On i»mkiKiii««
af ttr*ww»i' MnafM*. "¦—ttt' b*
Vii^«aa«< J. t.	md CC liw
UT. Ovum aai^M tm i*» im^.i if
¦iwace** «0*oi ti m w/nmm m
au«T«LJunu Itaira I'
*ruui I D in Th*	ai>4
fe'(T«uii<« tl ubM m* a haaltb
)Mi>u kartmo IUMI
*«l'r* LO.aMTl K»l/*f4 in.
Atd'ii>«. ¦wliifLcan*a kti njin m4*Ii
tm toia iukj Am. | |pim« Aaaaaee*|i al
UuJudum.ui CaniaaiMnan MiUa. kaly
tppj Mniijr af J ft Wiitejrl
WHO [^A«rM Naalik O^Miattarl IW1
H**lih affacvi §1 mmbtntd cxini la
ti *art ¦mrMwai. WHO Tack la#an
tana* Na ML
 So«rd ISAJS) on March 4.1IU
At Hi April 1T-23 IK! eMtmi th<
(AJ ?«nil pns«d*d lh« Aftncy arith
adi/ueruJ luf/fisonj ind
r*a ppiejou vvd
*ddrti»*d Iwvti ha i iifltiy ol
yanpactvii to rtaporvM ueouuli
ft* Afncy bai nodjnvd ar cknltd
sat^ **raoonf ifetCtudiluw. ud J*
|luuun| to d«v«lop • tKtaiCAl iitppon
rfocurttni in Una with tht SAJ
mommtnditioM Th» 4iteua«on tbot
foUowi kiMifhu tl^irturi Ioimw
mud ub Jit cematnti tod list
Afioqr i roiponit lo ifcim- Alio, many
mu\ot neomntndotiow «fuci do tot
•irtini dueuaaion btn. »»n odopiod
6y (fei Afcttcy
B VcmwmaM Pmdum
A DafaJ&c&a
tavmt oovmmtt w*rt iwafvtd
¦oncamni iKt lack of daKnitioru for
oaruiB Ity itmi ind fmrrtt
¦ndtrttandability «f etnain aact>ona
DtfimiiMU feivi barr Fttmnn for
oavtrtl lamu and 0m tti< fcai totn
litrjfietntft i*wntr«n it cJtnft Ar
A|«KT I t&UCI Ubd HUU|
oDdimtnion toud (At lack of
I P^cim t
torn ^tturt' li uualljr dJTi"»n.»>*d
km rua aolufiou »nx ibi Isnorr
daftaad aa ua^OBotiniovi
¦WticoBpontm iftuni For^ir
Gwdiltnti iWtan "^uturv'ti
iaftntd aa . a/ir eoabiAtuoo af f»o
•r am ci*micali rtftrdJaii of ipabal
ar import! kcmogrnnty of ioutu"
(aacQon 1) TU*t CudtLiwi an
litndad ia corf J ruk aaaaumtnu for
U) utiiiuoe witrt Ihr popuJatioa t»
Rpoaad arpoimtitly npoaad latao
or acrt coBpov&dt of cenetm.
CMttqartUy. tht feBPodurngn ba* botn
nviaad u tiintt lb Mtaedad bnadLh
¦f tppUubaa.
—r") tr< th*
data tad	tu
1 Vol II No. IIS ( Wadnidoy 5«pt(y.t*r U 1«M t h'etlen
urMnatnul povp thi tnleut ootild
taauc* Boruliiy Ai ¦ lowar tot « th«
uai iiudy to advtiw tfftrta would bo
•b*«nrfd mdudjt| n# urcuwffBJC
officii TS» data »o«Jd thaa ngnt mo
•fa tfuiihold ippfoach Si/ioo
tBrwoftniei") u wuidtrtd by tha
Aj« ncT to b« • nonthntbold a IT on. tt
*j> rot bt prvdtni 10 conjsrvt iho
W|iur« fllulll Of hrth I biMtlljr U
bdiciuni i>r ibMnet el nii ti lowti
tfoaai Conatqwtsily At Afrrey bti
rwrt+d i>« diicuauoe of lit pnfrmd
approieh to alio* Oit nak iwwr tt
t*aluan «i|« tW
b*v# bota rtviMd In th« ftaal
Cwdihati u tUrJt (W A«o*cj'i letcat
tad pooboa.
A Ceapl*t Hixrvm
fti l««vf ol ihr	of u
kMuApdon oT idlitiyiiy u eenplta
¦vxturn coniimmi trna or budn^* of
coapontnu *11 rt>i*d t« aovral of tho
public eoammu Tb» Ajnty t£d IU
rtrtawtri ipi thai at i« ausbe ol
oompourdj ihr Bjjitvm treroaML u
tuutnpiJOfl 0/ td&unry aoU tm 11 Bl
t*w nliablt ji Hiiaatiai nak TkU to
biMd on vht Ian ih»i ivc>. eovpenmt
otuaa'f of mi or u acc*p>abfa Wr»{ it
auocjutd »ii> *cvu rror and
itnuftamry With curve 1 knfltrMft.
0*4 mrcmiiary «rm tBcraaaa 11 lb#
unbar of ooapaMtf iflotcota U uj
flvtBL litUc axptnstnial dau ut
«*a Jabla te dttrmni (ht |«rural
cLuf* is tbt rw ai t&a Butturo
wnulai sort ocr.ponmu TSt A^mey
bat doodad Uin a unit 10 nu/nbor of
eoBpontnu ihojd oot bt it' it ibna
CiuJ1 L^t 1 Ho*»*ir. Ota Cmdt!jiit do
rrplitiiiy *uit itat •• tba eusbcr of
oaetipovndo a ii» Bixtun menaiti th«
Kearumty umqiiW wufexhi nil
liNimtai it tlte likily u tzkcraaaa
L Ooao Additlvlty
CoBSfBion won esneoraad about
wbai tpptantf w ba a rkeaAradauoa
tlthtuM of iddJtj*)ry for
ocrripounds that Induct dilTtrmi ffTocu.
Tht duoamoo foUo«iri| thi doao
idijuvity o^uauon *at danfiad 10
lediCdft tint ti* tet otcoabuuot »tl
ooppounda t*«a If (hay isdueo
AutLOiilar tfTictL la a aattunt
prooatfun aad aoi (fe« pnfrrnra
procadttn 10 dtvilcpi^i a baurd tadai.
Tba CuidiUaai »«n funbrr clarify 10
Kilt (An data (or mponaai additmiy
la thnrvucally touni and titrtfor*
ban applied for auaHini ouimm of
uauLa; arua| eospoa«nu ^41 d< oot
C iatifTRUtin of (&t KuH It^n
SwTtnJ eaaaanii ad£.*rtiid tfct
Ciannal lor B.iJa,t»r^niii.en ol tht
tird Indtn. mi lomt qutmontd ito
tabdify niiiduni tkn 11 utii taaaca
tad ra!«t |at^n/r.u bf uiinj
'aecapubla ' lavili in tht calculation.
Tht Ktinci i^hi «ath tht poiiibft
floofwion mtMini i(a wa and hai
mitod Cba Cwdtluiti Tor elanAcatlocL
Tba baurd indti U aa nnl)r danvtd
mutatam of dow iddiu«ity and it.
Vbartferi. aoal accvirtta whan uatd «nth
¦ixfun oonpantnu (hat havt iimila/
lesJc action. Wh«n wad with
araponanti of unkrowv or dinUnilar
actjoa. ihi hvard mdtx 1* !*•> accurtto
ajid ahould ba iAtarpntad onJjr at •
foufh lAdiciuon of oancom. Aa with
4tm addition th« aBerrtil/try
aaaodaiod with ihi lauH tadta
Imam u tha susbaf of ooBponnta
lamaw k tAai (((a ita* fffnpfuu
(or waluaurt tht tsucity of uaplti.
D Uao of latarartioc Dau
A fow ooAtttnion iuo«itt4 that any
toiaraaioo data ibouid ba «a«d to
quaniitativalx altar thi nak amiiBML
Tbt A#trvo d uptt Tha eurvfii
InfonBauee n intirvtaona ta citapar.
witfi «eJr * f*w ttuditt eonpinni
mpente to iKt Biatun wtih that
ptvdiatd b? irvditt on compormta.
Addilional MBBtnamittt i/vcludi
«(#aaun rvuuotu 4<*t 1* dUAftt !¦
•ompotivoa. miKtun doit tnd iptnta
di/Ttrmcai tD tht tuini of tht
tataricboa Tit Aftncy l» comtrucuni
w mtaraeeoo data bait in an axtmpt 10
AftiartT KDI Of Ihtlt llivtl 0^l»
msiA'J eoncanid tht uat of d.ffttr.t
fypai of isitnetion data T>« CuidttJtti
rtitrci tha wa of tfttiriction data la
Cfcji obtoiAtd fras wholt amna)
Voamyi of 1 dvn'-wn tppnpnamo
At nil aitciimant Imca ludi dtia on
fro^uiftLlj ladtiof at Ltaai for ehramc or
avbchraiuc afTtcta. tht iaaut ti whtthcr
le allow for tha uaa of othtr infomatioa
avch aa acvtt data, m ntro daia. v
ttr\jcturo-actmt> nlationahipi to
euiMd in which tht nib aaaaiiof ta
prtitntad *nth tseovpltii touciiy.
B0flit«rv4 ot axooaon dau Tht &AJ.
aa w«Ji tt »4*tri) public comaootofa.
naasianded thil tht 'TU*
BmntTtr.r isat of iJui unn ba
Bodifitd and tin tha opticn of At nil
oiMiior to dtdmt to cosdwci a mk
•wttistnt b« ttidt BOf« tiplicit
Tin U a dificyti iaaut thai ffiuit
opniidtr aot only tht quihiy of tht
availablt data for ruk amuntnt but
•lie thi awda of tha A|*n^ B n*t
Bani|tmtnL Civan tht fypai ol poor
dau elitn amJtblt (ha nak ttttttar
aay uidjtan thit tht mk aiMiamtnt ia
baMd on UaLttd information and thua
cestaina no ^uantificarion of mk
Nontthtltn in any nik aiittimtni
tubinniiil tufctntmiiti auii It n tht
ebl4inon of tht nik aiitiior (0 pm >d»
on 1t11111r.nl but alao to aniun that
all tht oiiuaipnotu asd uneanainuta
an anicWattd cJtarty and quantifitd
wKtni*tr pombla.
T%i SAS arfinJatod aovml olhor
ftccauBindatiorn rtlatad ta
¦AciRamtita all of wbiihharabotB
foliow«d tit U10 nvtaioe of tha
C«Jdtlino« Om roc««atndatton wta
thu tht lu&aury moodurt ublt alao
^o pfHtaiod ai a flow cftan to that all
opuona art ekarly dupltytd Tht SAS
funhrr roooBVBtndad tht dtvtlopmaat
of a lyttam to tipnta tAt l«vrl of
ABflfitftnca ta tht vanow nrpi of lha
nak aimimtnt.
T>>« A#«nqr bai i«*iaod tha aumsary
ublt to o«*Mnt few biiot optiona nah
aiianmr" wla| data oa tht Biintra

fadaraJ lafJttar I Vol SI. No IAS I W»dnndiy fcptfnbr U 1Me / Ko'ien
toe If diu m • tfraUar matw* data oe
Ac aurun i aospontnu or dediamt
10 quantify (hr nik when the data a*
kudrqwut A Oow then of thie table
kti alio b*en added to row dearly
depict the »»ne«i opuo&a and to eu0*it
the eombmini of ihe Mvtnl optioru to
Indicate th« variability and uMenamoei
to the nil aaieumont
To ddtnninr the adequacy of the
lata the SAB alio rteommended the
development of a eyetem to eipreie the
level or confidence aiaoeaied with
vanoui nepi m iii« nek aieuiment
proc«i» The A|eney hai devtloped a
ratini aehtmt to deaenbe daia qualify la
thrtt artat uunruon health eflecu.
and etpoiura Thu daiaificauon
^rovidei a nn|r of fivi of data
Jui'it) for each of the throe artai
hoonn| the l»ii level in any ana
reiulti in dtdiivjrvi to peHor® a
quantitative nik aiMiiment due to
tnadeQuitr dm Their lau Ieveli or*
deicnbrd ai follow#
An anumption of add.f.viry cannot bo
(uitifitd and no quantiteuvi nik
aiiriimeot cad be conducted
Hee';h effect!
A lack of health tffrru Information oe
(hi muru* ud iu component!
prvdudei i quantitative nik
ike available etyoiun la/orwation la
tUufTicient for ooedueu^ a nak
(•vera! coouaentoro tncJudini the
&AJ emphaiued the importance of aoi
loaiAl then deinficationi and
scanaintiei farther alonf in (he dak
Barutement orocen Tfct diecumon of
aacanaintiet ui been eipanded tn the
foal Cwdelinee and include! the
ncommvndabon thai a diicuanoft of
ancanamijee and aeiuaiptiona bo
fcduded at every atop of the Wfulatofy
froeni that via nik aaaeianent
Another SAB coaaent «rai that tho
Cwdelmei ihould tndude additional
procedure! for ails turn with mow than
are end point or effect The Agency
ip«i that thee* art ooncami and
wnaed the Guideline! to emphaeue
th*ee at additional uacanamuei worthy
af funher rtoearch.
V Smd for 0 TtcX/uael Support
Tie third saior UI oDmant
aonoemed the necftury for a Mperete
technical luppon document for theie
Cuidelmet The SAB pointed out that
the ocientific and technical baci^ound
he which their Ciudrlmei auat dri»
their validity u 10 breed and varied th.it
It caoaot riaionably be eynibeioed
within the fraarwori of e bn»' tf of
Adeline* Tbe A^icy dons; *| a
lachrucal Mppon doewne-.'the ».il
M0vmiAi* the avaJiblr ir.foi-ra-isn oe
health effect* foa tftemica' miat.rei
and on inurtttoe r«chen.imi ei will
aa idenufy and iovelop mitheBit.cal
•odeli ud eutieou! techmquri to
wppon their Ciudelinei Tbn document
anlJ alio identify muca! gapi ar.d
mearch aoade
lemal caoAMt* addmitd the na»d
for etaaplei on the km of the
CuidelvAM T%* Afeney hei decided lo
todude tunpln te the laehnital
•u^pon doewnent.
Another taiwe mud by the SAB
aeaaernod the tdanuhcation of neearch
aatda Becauae bnJ« enpham hai brtn
placed oe the todcolofy of auitum
anul rvcntJy the t&formation on
•itturvt ta L&tted TW« SaB pomted ovt
that identifytni nwearch oteda n a^'.cal
lo the nik eiMuamt prootit and the
l?A ahould eruurt that the*« aetdi tit
aonaiderad is the rvaearch planntni
pan The Agency anil melude a
aecuon in the techmcal lupport •
docunwni that idenufiee rvaeareh fteede
rtfardini both eethodolefy and data
(T* Doc	Tj»d o-o-A i«iirj

S«ptrTto«r 24, 1986
Part II
Protection Agency
Guidelines for Circinogen Risk
Arnum nt