United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5305)
EPA530-S-94-001
December 1993
&EPA
Report to Congress on
Cement Kiln Dust
Executive Summary
Printed on Recycled Paper
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EXECUTIVE SUMMARY
1.0 Introduction
1.1 Background
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In October 1980, the Resource Conservation and Recovery Act (RCRA) was amended by
adding §3001(b)(3)(A)(i-iii) (the Bevill Amendment) to exclude, among other things, cement kiln
dust (CKD) from regulation as a hazardous waste under RCRA Subtitle C, pending completion of
a study and a Report to Congress required by §8002(o), arid a subsequent regulatory
determination of whether Subtitle C regulation is warranted. In November 1980, the.
Environmental Protection Agency (EPA) subsequently modified its hazardous waste regulations in
RCRA §3001(b)(3)(c), to reflect the provisions of the Bevill Amendment (40 CFR 261.4(b)(8)).
Since that time, cement kiln dust has remained exempt from Subtitle C of RCRA, meaning that
this material has never been subject to the hazardous waste regulations under federal law.
Because of other priorities, EPA did not complete the Report to Congress by the.
statutory deadline of 1983. On March 8, 1989, the Environmental Defense Fund (EDF) filed suit
against EPA for missing the statutory deadline, and the American Petroleum Institute and the
Edison Electric Institute intervened in the case. On June 19, 1991, EPA entered into a proposed
consent decree with EDF. In the proposed Consent Decree, EPA agreed to complete the Report
to Congress on Cement Kiln Dust by April 30, 1993. The proposed Consent Decree was later
modified and the deadline for completion was extended to December 31, 1993.
In keeping with its court-ordered schedule, and pursuant to the requirements of
§3001(b)(3)(iii) and §8002(o) of RCRA, the EPA has prepared this report on CKD. In addition
to complying with the Congressional mandate, this report will serve to establish a factual basis for
EPA decision-making regarding the appropriate regulatory status, under RCRA, of cement kiln
dust The report addresses the following eight study factors required by §8002(o) of RCRA for
CKD:
(1) the source and volumes of such materials generated per year;
(2) present disposal practices;
(3) potential danger, if any, to human health and the environment from the disposal of
such materials;
(4) documented cases in which danger to human health or the environment has been
proved;
(5) alternatives to current disposal methods;
(6) the costs of such alternatives; -
(7) the impact of those alternatives on the use of natural resources; and
(8) the current and potential utilization of such materials.
,In addition, the report includes a review of applicable state and federal regulations so that
regulatory decisions that derive from the report will avoid duplication of existing requirements.
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1.2 Decision Rationale
To examine in detail the study factors mandated by RCRA §8002(o), EPA developed an
approach that combined certain study factors into groups along functional lines. These sets of
study factors were then evaluated in a step-wise, logical sequence. This approach, the decision-
making rationale, has been used in making regulatory determinations for other Bevill exempt,
special wastes1. In this process, which is described in detail below, the Agency considered the
study factors, first assessing the adequacy of current management practices and whether such
management poses human health and environmental problems, then evaluating the need for more
stringent regulation, and lastly, assessing the operational and economic consequences that would
result by regulating this waste under Subtitle C. Each step has sub-steps addressing related study
factors, and an affirmative answer to one step forwards the decision-making to the next step of
the analysis. . : ;
Several assumptions guided EPA in applying this decision-making process to cement kiln
dust. First, the Agency recognizes that explicit decision criteria are necessary to achieve
reasonable decisions regarding the need for additional regulatory controls.; Second, the study
factors most critical to determining the regulatory status of CKD are risks posed and documented
damages caused by the waste, and the costs and impacts that would be associated with more
stringent regulatory controls. This is because without potential risk and/or documented damages,
there is no need for hazardous waste regulation under RCRA Subtitle C (the key issue in
question). Alternatively, if there is a significant potential or documented danger, the costs and
impacts of regulatory controls must be carefully evaluated to ensure that these options would
provide adequate protection of human health and the environment and continued operation of
the affected facilities. In employing this second assumption, the Agency believes that it has
developed and analyzed regulatory compliance scenarios that are realistic from an operational and
engineering standpoint, and that are likely to be adequately protective of human health and the
environment.
Evaluation Criteria
Step 1: Does management of CKD pose human health and environmental problems?
Might current practices cause problems in the future?
Critical to the Agency's decision-making process is whether CKD either has caused or
could cause human health or environmental damage.
(1) Has CKD, as currently managed, caused documented human health impacts or
environmental damage?
(2) Does EPA's analysis indicate that CKD could pose significant risk to human health
or the environment at any of the sites that generate it (or in off-site use), under
either current management practices or plausible management scenarios?
(3) ' - Does CKD exhibit any of the characteristics of hazardous waste?
1 The Regulatory Determinations for mineral processing special wastes (56 FR 27305, June 13,1991) and
four large-volume wastes from the combustion of coal by electric utility power plants (58 FR 42466, August
9, 1993).
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If the answer to any of these three sub-steps was yes, then EPA would conclude that further
evaluation was necessary. If the answer to all of these questions was no, then the Agency would
conclude that regulation of CKD under RCRA Subtitle C is unwarranted.
Step 2: Is more stringent regulation necessary and desirable?
If CKD has caused or may cause human health or environmental impacts, then EPA
would conclude that an examination of alternative regulatory controls was appropriate. Given the
context and purpose of the present study, the Agency focused on an evaluation of the likelihood
that such impacts might continue or arise in the absence of Subtitle C regulation, by posing the
following two questions:
(1) Are current practices adequate to limit contaminant release and associated risk?
(2) Are current federal and state regulatory controls adequate to address the
management of CKD?
If current practices and existing regulatory controls are adequate, and if the potential for impacts
is low (e.g., facilities in remote locations), then the Agency would tentatively conclude that
regulation under Subtitle C is unwarranted. Otherwise, further examination or consideration of
regulatory alternatives would be necessary.
Step 3: What would be the operational and economic consequences of a decision to
regulate CKD under Subtitle C?
If, based on the previous two steps, EPA believed that regulation of CKD under Subtitle
C might be appropriate, then the Agency would evaluate the costs and impacts of regulatory
alternatives. In the case of CKD, EPA evaluated two regulatory alternatives that are based upon
Subtitle C, one alternative that reflects one possible approach that might be taken under RCRA
Subtitle D, and other possible approaches (i.e., engineering alternatives) that might be employed
by potentially affected cement plant operators. The focus of this inquiry was whether .the
magnitude and distribution of regulatory compliance costs might jeopardize the continued
economic viability of one or more generators if the waste were to be regulated under the Subtitle
C regulatory scenario. The key questions in the Agency's decision-making process were as
follows:
(1) Are predicted economic impacts associated with the Subtitle C scenario significant
for any of the affected facilities?
(2) To what extent could these compliance costs be avoided through the
implementation of alternative CKD management practices?
(3) In the event that significant impacts are predicted, might a substantial proportion
of domestic capacity or product consumption be affected?
. (4) What effects would hazardous waste regulation have upon the viability of
beneficial use or recycling of CKD?
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In EPA's judgement, absence of significant impacts would suggest that Subtitle C
regulation might be appropriate for CKD if findings indicate that it poses significant risk. If even
less stringent Subtitle C standards impose widespread and significant impacts on facilities, and/or
deter the safe and beneficial use of the dust, EPA may conclude that regulation under some form
of Subtitle D program might be more appropriate. •
1.3 Organization of the Report to Congress
This systematic approach employed in EPA's decision-making process is mirrored in
chapters of the Report to Congress. EPA has organized the discussion of the analysis (Volume II
- Methods and Findings) into chapters that address each segment of the study. The first chapter
introduces the analysis with a brief summary of the purpose and scope of the report, general
methods and information sources used, and EPA's decision-making methodology. The second
chapter begins the review of the analysis with a brief overview of the industry, including a
description of CKD waste, the industry structure and characteristics, the cement manufacturing
process, the types of production processes used, and significant process inputs (Study Factor 1).
The third chapter of the Report to Congress discusses the generation and chemical and physical
characteristics of CKD (Study Factors 1 and 3). The fourth chapter outlines the range of CKD
management methods employed at domestic cement plants (Study Factor 2). The fifth chapter
identifies and summarizes cases of potential and documented damages to human health and the
environment (Study Factor 4). The sixth chapter includes a discussion of EPA's risk assessment
in which the Agency examined inherent hazards posed by CKD, evaluated site-specific risk
factors, and performed quantitative transport, fate and exposure modeling (Study Factor 3). The
seventh chapter summarizes applicable federal and state regulatory controls. The eighth chapter
investigates alternative waste management practices and potential utilization of the wastes (Study
Factors 5, 6, and 7). The ninth chapter discusses costs and impacts under each of several
regulatory and operational scenarios (Study Factor 8). And finally, chapter ten presents EPA's
study findings and regulatory options.
2.0 Information Sources and Methods
The Agency's approach in preparing the Report to Congress was to combine certain
study factors for purposes of analysis, and to evaluate these study factors in a step-wise fashion.
In support of this analysis, EPA has developed industry-wide and facility specific data and
analytical methods that have allowed the Agency to incorporate the information into the decision
rationale in a logical fashion, while accounting for the special nature of the cement kiln industry.
This section briefly outlines the data sources, methods and decision rationale that Che Agency
employed to respond to the study factors.
2.1 Data Collection Activities
In compiling information to address the eight study factors, EPA conducted a number of
research and data collection activities. Since the focus of most of these efforts was site-specific,
EPA has been able to compile reasonably detailed industry-wide information, which the Agency
used extensively to prepare this report. The major information gathering initiatives were as
follows: . -'.--."'--!-.--
" Portland Cement Association (PCA) 1991 Main Questionnaire Survey of Cement Kiln
Facilities:
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EPA site visits to cement manufacturing facilities to familiarize EPA staff with the cement
manufacturing process and CKD management techniques;
1992 and 1993 EPA site visits to cement manufacturing facilities to collect'samples of
cement kiln dust;
• State agency files (reviewed as part of the effort to identify proven cases of-danger to
human health or the environment, referred to as "damage cases");
RCRA §3007 Waste and Site Characteristics Data Requests;
2.2 Methods ...'",
This section summarizes EPA's approach for addressing each of the study factors.
Waste Characterization, Generation, and Current Management Practices
1991 Survey of Cement Kiln Facilities
To characterize the generation and management of cement kiln dust, EPA had to identify
the facilities that generate the wastes, the production processes used and the products produced,
the quantity and characteristics of the waste generated a.nd the practices that are employed to
manage CKD. The Agency contacted industry representatives to determine if such information
was available. PCA responded by developing a questionnaire for its members, that garnered
information regarding CKD. The results of the PCA survey were made available to the public.
EPA used this information to support its analysis. Specifically, the questionnaire addressed CKD
waste characteristics, generation, and current management at clinker producing facilities (CKD
Generation and Characteristics, Chapter 3; and Current Management Practices for CKD, Chapter
4); as well as on the operational characteristics of the industry (Cement Industry Overview,
Chapter 2).
One hundred and fifteen cement plants were identified through industry and U.S. Bureau
of Mines Sources that were believed to generate CKD. The survey was prepared and distributed
to the facilities in December 1991, by the Portland Cement Association. Approximately 80
percent of the facilities surveyed responded to the questionnaire, which addressed waste
management and tracked CKD from point of generation through its ultimate disposal (through
on-site recycling, on-site disposal or off-site beneficial use). Responses to the questionnaire were
provided to EPA, and entered into a computerized data base, which EPA has used in this
analysis.
Information submitted by industry in response to the survey was supplemented and
critically evaluated against data obtained from published sources, information collected during the
damage case development process, and EPA observations made during waste sampling and other
visits.
RCRA Section 3007 Data Requests
In order to allow affected facilities to have meaningful input into the Agency's evaluation
of physical and chemical characteristics of CKD (Chapters 3 and 4), EPA issued a formal written
request, under authority of RGRA §3007, to 115 cement plant operators seeking any currently
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available information on the characteristics of the dust that they generate. The Agency
specifically sought information on the presence and concentrations of organic and other
constituents in CKD, patterns of off-site use in productive applications, and site-specific
environmental characteristics of those plants for which PCA surveys had not been received. To
make compliance as easy as possible, the request did not specify a data format or the quantity of-
data required. The Agency has reviewed all of these data submittals and has collected and
utilized the data that are relevant to the analyses presented in the study.
EPA Site Visits and Cement Kiln Dust Sampling and Analysis
The primary objective of EPA's site visits and sampling effort was to bolster the Agency's
data base on CKD characteristics and other plant specific information e.g., production rates, kiln
operating information, etc. (Chapters 2, 3, and 4). (Additionally, the results of the sampling effort
supported the Agency's review of potential and documented damage cases.) The site visits served
to enhance the Agency's general understanding of the processes whereby CKD is generated, and
of the techniques by which it is and could be managed (Chapters 3, 4, and 8).
Since EPA's Office of Solid Waste (OSW) had not previously studied cement kiln dust,
during the summer of 1991, EPA staff visited two cement facilities to gain ;a general
understanding of CKD waste management practices. In the early part of 1992, EPA conducted a
CKD and cement clinker sampling and analysis program (referred to as Phase I in the Report).
The Agency's field sampling teams visited 15 cement facilities, recorded observations of
operational practices, took photographs of waste management activities, and collected samples of
CKD and clinker. EPA generally took CKD samples on both an "as generated" basis (directly
from the kiln at the time of the site visit) and on an "as managed" basis (CKD from 1- to 6-
month old disposal piles). :
In May 1993, EPA conducted a second more focused CKD sampling and analysis program
(referred to as Phase II in the Report), to clarify certain analytical issues raised by the results of
the Phase I and analysis effort. Specifically, the Agency visited and took CKD (and in some cases
clinker) samples from six cement plants, one of which had been visited in Phase I {for purposes of
verification of Phase I sampling results), and performed various chemical analyses. The CKD
samples were analyzed for the following classes of analytes: volatile and semi-volatile organics,
pesticides, PCBs, dioxms, furans, metals, radionuclides and general chemistry. One important
distinction between the two sampling and analysis programs is that the analytical methods
employed for measuring dioxin and dibenzofuran concentrations in Phase II analysis were more
sensitive than those used in Phase I2. The knowledge and insights gained during these 21 site
and sampling visits have enabled the Agency to understand and evaluate current waste
management practices and the chemical characterization of CKD.
Potential Danger to Human Health and the Environment
EPA is required by §SQ02(o)(3) to assess the potential danger to human health and the
environment associated with CKD management. To evaluate potential risks to human health and
the environment from the management of CKD, EPA employed a three-step analysis of potential
2 The data developed in the Agency's two-phase CKD sampling program may be found in summarized
form in the supporting docket for this report (Docket No. F-93-RCKA-FFFFF), while a description of EPA's
waste sampling study is presented in a Technical Background Document, which may also be found in the
docket.
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risks from on-site management practices (Chapter 6). This allowed EPA to narrow the scope of
the analysis to those CKD waste streams, facility settings, and pathways that pose the greatest
potential risk. First, the Agency conducted a preliminary risk screening, to determine the extent
to which the dust contains toxic or radioactive constituents that could pose risks to human health
or the environment. To identify the "constituents of potential concern", EPA compared
concentrations of chemicals measured in CKD to "risk screening criteria". These criteria were
developed using accepted Agency toxicity values and conservative chemical release, transport, and
exposure factors. Other chemical and physical properties that may tend to mitigate or qualify
risks associated with particular CKD constituents were also evaluated.
The next step was to conduct a more realistic case study evaluation of the likely degree of
risk at a series of 15 representative cement plants. This study focused on the specific waste
constituents, net generation rates, current CKD management practices, environmental settings,
and surrounding residential and other land use patterns at each of the 15 plants, as developed
from the PCA survey and EPA site visit and mapping data. Potential relative risks from possible
releases of CKD constituents (via ground water, windblown dust, and surface stormwater run-off)
were thus evaluated semi-quantitatively on a site-specific basis at each facility for each feasible
pathway of concern. All 15 facilities were then ranked into relative potential risk categories
(negligible, low, medium, and high) for each pathway.
The two highest ranked cement plants and three plants representing more central
tendency risks for each risk pathway from step two were then selected for a detailed quantitative
evaluation in the third step of the on-site management risk assessment. For the quantitative
assessment of these situations, the Agency used a multi-media risk model ("MMSOILS") to
estimate risks to human health and the environment. The study focused not only on the direct
constituent transport pathways (ground water, surface water, air), but also on indirect food chain
pathways, including local farming and fish products that could biologically concentrate toxic
constituents and that might be locally consumed in larger or smaller quantities by various
population groups.
In addition to on-site management scenarios, the Agency evaluated the risks associated
with the beneficial use of CKD at off-site locations separate from cement plants. Six case studies
were developed from data on the nature, extent, and location of off-site CKD uses, including uses
in general construction, highway and parking lots, waste stabilization, and as a substitute for lime
and fertilizer in agriculture. The Agency then collected additional data on risk factors associated
with each of these case studies, evaluated potential release and exposure pathways, and developed
hypothetical (but plausible) scenarios representing both central tendency and high-end potential
risk conditions that could exist when CKD is used off site. The human health and environmental
risks associated with these off-site use scenarios were both qualitatively evaluated and selectively
modeled.
The Agency used these steps to evaluate the range of conditions and risks that exist across
the industry, while also identifying and focusing on those CKD constituents, waste streams,
management practices, facility settings, and pathways that pose the greatest potential risk.
Documented and Potential Damages to Human Health and the Environment
§8002(o)(4) of RCRA requires that EPA's study of cement kiln dust waste examine
"documented cases in which danger to human health of the environment has been proved." This
section describes the approach the Agency has employed to address this requirement. First, the
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Agency defined damage to human health to include both acute and chronic effects (e.g., directly
observed health effects such as elevated blood lead levels, or loss of life) associated with
management of cement kiln dust waste. Second, danger to the environment was defined to
include: (1) impairment of natural resources (e.g., contamination of any drinking water
reasonably expected to be used, impairment of air quality); (2) ecological effects resulting in
degradation of the structure or function of natural ecosystems and habitats; and (3) effects on
wildlife resulting in impairment to terrestrial fauna or aquatic biota (e,g., reduction in species
diversity or density, impairment or reproduction).
EPA used the "tests of proof used in previous Bevill Waste Determinations3 to evaluate
potential damage cases. Damages are found to exist: (1) as part of the findings of a scientific
study; (2) through a formal administrative ruling (e.g., conclusions of an enforcement action); and
(3) through the ruling of a court or out-of-court settlement.
EPA conducted an exhaustive examination of the extent to which CKD has been
implicated in environmental contamination incidents in response to the mandate to describe
documented eases in which danger to human health or the environment has been proved
(Chapter 5). In undertaking this effort, staff were contacted in all EPA regions and states in
which one or more cement kiln facilities is located. Where telephone contacts indicated that
relevant damage case information might exist at the regional, state, or local level, the information
was obtained through the mail or through visits to state/local officials having regulatory
jurisdiction over CKD management.
The Agency's damage case analysis is based primarily on documented evidence, rather
than on visits to the sites being evaluated. However, the Phase I waste sampling visits to the 15
facilities also included an effort to collect information on the existence of potential environmental
pathways through which CKD and its constituents might migrate and cause adverse impacts. The
results of this effort is a compilation of information regarding past and present management
practices that have been applied to CKD, and the environmental or human health consequences
of these practices4.
Existing Federal and State Waste Management Controls
In response to the suggestion in RCRA §8002(o) that EPA "...review studies and other
actions of federal and state agencies", with a view toward avoiding duplication of effort, EPA has
also examined other applicable federal and state waste management controls to help characterize
current waste management practices (Chapter 7).
3 The Regulatory Determinations for mineral processing special wastes (56 FR 27305, June 13, 1991) and
the four large-volume wastes from the combustion of coal by electric utility power plants (58 FR 42466, August
9, 1993).
4 In addition to the description provided in Chapter 6 of this report, the individual sites that have beeti
evaluated in detail are listed in the supporting Technical Background Document (Docket No. F-93-RCKA-
which also provides more extensive discussions and supporting evidence.
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Federal Controls
EPA's objective in this analysis was to identify and evaluate existing regulatory controls
over the management of cement kiln dust that have been promulgated by agencies of the federal
government.
In the initial phase of the analysis, EPA examined the relevant statutes and regulations
pertaining to air quality, water quality, and solid waste as they might apply to the management of
cement kiln dust. In order to develop a baseline of information about current federal and state
regulations, EPA conducted an on-line search of the Computer-Aided Environmental Legislative
Data Systems (CELDS), a data base containing abstracts of federal and state environmental
regulations.
EPA identified and evaluated existing federal regulatory controls on cement kiln dust,
focusing on programs and requirements established by EPA. This characterization is necessary for
two reasons. First, some states do not have EPA-approved programs for regulating air pollution
emissions to the atmosphere or discharging contaminants to surface waters. If a state program is
not federally approved, then federal EPA regulations take precedence. Second, the federal
government has not delegated authority to some states for implementing some environmental
protection statutes and regulations and is thus responsible for their implementation. In those
states that do not have federally approved programs, EPA regional staff were contacted for the
purpose of conducting a detailed regulatory analysis of the implementation of existing federal
statutes and regulations that pertain to the management of CKD.
Requirements in Selected States
After reviewing federal regulations, the Agency then performed a more detailed review of
state statutes and regulations. Scheduling and resource limitations made it impossible to perform
a detailed regulatory analysis on all of the states that contain cement plants. Consequently, EPA
limited this review to four of the states with the largest clinker production and finished grinding
capacities; together, California, Michigan, Pennsylvania, and Texas represent over.35 percent of
1990 clinker production capacity. EPA assumed that these states would have the most extensive
experience in controlling the management of cement lain dust and would have the greatest
interest in regulating CKD.
EPA contacted state and local officials involved with implementing CKD management
requirements in order to learn how those statutes and regulations are interpreted in practice, and
to obtain facility-specific implementation information. EPA had found that the scope of state
programs is not always clear from the state statutory and regulatory language. The information
compiled from these contacts was combined with the existing information on statutory and
regulatory requirements to produce the final implementation analysis.
Alternative Management Practices and Potential Utilization
§S002(o)(5) of RCRA requires that EPA analyze "alternatives to current disposal
methods" for cement kiln dust, as well as the current and potential utilization of the. wastes
addressed by the Report to Congress. In this analysis, the Agency viewed technologies that are
available and under development to minimize the quantity of CKD that must be removed from
the kiln system, and alternative management practices and potential uses for the net CKD that is
generated (Chapter 8). .•
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Information for this analysis was collected by first conducting a comprehensive computer-
assisted literature search, then evaluating the information obtained thereby. In some instances,
more detailed information was solicited from individual researchers, agencies, and industry
representatives. Discussions with plant personnel during facility site-visits also provided insight
into alternative management practices. Detailed discussion of alterriatives is limited in scope,
however, to those for which information is adequate to assess their technical feasibility (i,e,, EPA
has not included alternatives that are experimental, unproven, or have not seen at least pilot-scale
application).
Cost and Economic Impacts
§8002(o)(6) of RCRA requires EPA to analyze the costs of alternatives to current
disposal methods for cement kiln dust. The focus of this analysis, presented in Chapter 9, is on
the operational and financial consequences of adopting these alternative CKD management
practices under various regulatory' schemes. EPA first assessed the costs of managing CKD with a
variety of different land disposal and resource recovery practices. Then the Agency examined the
impacts of potential regulatory scenarios, given the costs of the various CKD management
alternatives, as they would be experienced by a representative sample of 10 selected cement
manufacturing plants.
This analysis draws on the information presented in the Report to Congress on current
CKD management practices (Chapter 4) and potential CKD management alternatives (Chapter 8)
including the use of emerging technologies for treating CKD to extract alkalis for sale as fertilizer
and reclaim the bulk of the material as kiln feed or processed clinker. Specifically, EPA has
collected and analyzed detailed site-specific data on cement plant operations and CKD generation
and waste management practices. The 1991 PCA Survey served as the primary data source for
baseline conditions, supplemented by observations made during the 1992 field sampling visits.
Basic design, operation, and cost information on emerging recycling technologies was obtained
from both published and primary sources. The Agency then conducted an engineering cost study
to apply these technologies to the case study facility conditions. Case study recycling costs were
then compared with current practice baseline and alternative Subtitle C land disposal costs to
assess compliance options and impacts. EPA based its assumptions regarding the economic
conditions facing the cement industry on industry and market data obtained by the PCA, the
Bureau of Mines, the International Trade Commission and the Bureau of the Census.
3.0 Technical Findings, Decision Rationale and Regulatory Options
§3001(b)(3)(c) of RCRA requires that the Agency, based on the findings of this report
and public comment, either determine to promulgate regulations under Subtitle C of RCRA for
cement kiln dust waste or determine that such regulations are unwarranted. Accordingly to
facilitate comment on this report and subsequent preparation by the Agency of the required
"regulatory determination", this section presents a summary of the Agency's analysis and possible
options, pending receipt and analysis of public comments, that EPA is evaluating regarding the
appropriate regulatory status of cement kiln dust.
3.1 Decision Rationale
Based upon the analysis of the eight study factors in RCRA §8002(o), EPA has reached
some preliminary findings. Utilizing the three step procedure described in Chapter 1 of Volume
II (Section 1.2), EPA has arrived at tentative answers to the questions posed in its decision
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rationale, which are described below. The decision rationale contributed to development of the
five proposed options for managing CKD waste (listed in Section 10.3.2 of Volume II), although
the Agency has not yet made a final decision. EPA is soliciting comment on how the, decjsjon
rationale can be used in the Agency's decision-making process.
Step 1: Does management of CKD pose human health and environmental problems?
Might current practices cause problems in the future?
After reviewing evidence of damage to human health and the environment, performing a
risk assessment, and reviewing the results of laboratory analyses of waste samples, EPA has
concluded that risks associated with CKD management are generally low, however, there is a
potential under certain circumstances for CKD to pose a danger to human health and
environment, and it may do so in the future.
Data collected from state files and EPA site visits identify common CKD waste
management practices, including management in exposed, unlined piles, abandoned quarries, and
landfills, that have caused, and may continue to cause, contamination of air and nearby surface
water and ground water. Management practices such as disposal in a water-filled quarry and
management in piles adjacent to grazing and agricultural fields or surface water bodies also pose a
potential danger to human health and the environment. In addition, risk modeling results support
the conclusion that CKD can potentially pose risks to human health and the environment under
certain hypothetical, yet plausible scenarios.
Step 2:
Is more stringent regulation necessary or desirable?
EPA has reached no conclusions with respect to the need for more stringent regulation.
EPA's preliminary analysis of the effectiveness of state and federal regulations and controls
suggests that additional controls should be evaluated; for example, controls for CKD management
scenarios which potentially present high risks, if those scenarios exist. While CKD is regulated
under state and local laws, the specific requirements for CKD Vary from state to state. In many
instances, minimal controls are applied to these wastes. Also, recycling technologies could be
used as a means to improve waste management practices.
Step 3: What would be the operational and economic consequences of a decision to
regulate CKD under Subtitle C?
Operational costs of CKD regulation are largely dependent on the management
alternative selected. If CKD is managed as a hazardous waste under RCRA Subtitle C, facilities
that manage their CKD through on-site land disposal "are estimated to incur significant compliance
costs. However, the financial burden of compliance, even for waste dust generated in kilns that
burn RCRA hazardous waste, may be reduced or potentisilly turned into net income, if facilities
are able to adopt pollution prevention technologies which recycle CKD. .
The possible economic outcomes of a decision to regulate CKD under RCRA Subtitle G
cover a broad spectrum. An econo'mic analysis of innovative pollution prevention technologies
(including .alkali leaching, flue gas desulfurization, and fluid bed dust recovery), suggests that the
potentially high compliance costs of CKD land disposalmay drive trie industry toward more
recycling of their CKD. However, at this early stage of their development, it is uncertain that
these recycling technologies carl be widely adopted by the industry. Moreover, even if CKD is
recycled, some facilities may incur substantial disposal costs.
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3.2 Regulatory Options
Based on the findings, and an initial evaluation of regulatory options, the Agency has not
decided whether to retain or remove the CKD exemption. The Agency considered a number of
options which represent a wide range of scenarios that would subject CKD to different
management requirements and enforcement oversight. From these, the Agency has chosen to
highlight five, including three in which CKD would be managed under Subtitle C, with the intent
to focus public comment from environmental groups, industry, and other interested parties
regarding the most appropriate approach to manage CKD.
EPA notes that regulations for the management of CKD waste under Subtitle C may not
be warranted or appropriate if other Agency-administered programs are better suited to address
the concerns identified in this Report. Whether or not the Agency lifts the exemption, dust
suppression and stormwater management at facilities that burn hazardous waste, as well as on-site
CKD management practices at all other facilities would be subject to current and potential future
regulation under the federal Clean Air and Clean Water Acts, and where such provisions exist, all
applicable state laws and regulations. Damages at existing CKD disposal sites also could be
addressed by RCRA §7003 and CERCLA §104 and §106, if the site posed an imminent and
substantial danger to human health and the environment.
Option 1: Retain the CKD Exemption.
Since CKD exhibits low inherent toxicity and poses minimal risk when evaluating the
various exposure pathways using average or best case conditions, it may be appropriate to retain
the exemption for cement kiln dust waste, that is, maintain the status quo. Under this option,
CKD management would continue to be regulated by the states, if at all.
Option 2: Retain the CKD Exemption, but enter into discussions with the industry, in
which they voluntarily implement dust recycling technologies, reduce waste, and
, monitor and control certain off-site uses.
Since certain management scenarios may present risks when assuming plausible worst case
conditions and pollution prevention alternatives may be promising in certain instances, the Agency
could enter into discussions with the cement manufacturing industry to urge it to implement
selected waste minimization/pollution prevention technologies, or implement more
environmentally protective management practices, including controlling certain off-site uses.
The Agency, under this option, could also develop guidance for states regarding site
management, off-site uses, and pollution prevention and waste minimization technologies. This
guidance would assist states In reducing the potential risks posed by mismanagement of CKD and
recommend implementation of technologies that would promote recycling of CKD.
Under this option, CKD management would not be controlled by the provisions of RCRA
Subtitle C. However, since the exemption for CKD remains in place, CKD generated in kilns
that burn hazardous waste would still be subject to the two-part test for residuals under 40 CFR
266.112. If CKD does not pass the two-part test, it would be treated to standards for land
disposal (40 CFR 268.43) and disposed in a Subtitle C facility. Damages at existing CKD. disposal
sites would still be addressed by RCRA §7003 and CERCLA §104 and §106, if the site posed an
imminent and substantial danger to human health and the environment.
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Option 3: Remove the CKD Exemption but delay implementation for some period of time
(e.g., two years), that would allow industry time to employ pollution
prevention options. _,,,.,...,_-_=._
By delaying lifting the exemption for some period of time (e.g., two years after the
Regulatory Determination), industry would be provided an opportunity to implement pollution
prevention alternatives and thus, manage the hazardous waste management costs they would
incur. During this interim period between submittal of the Report to Congress and the effective
date of the Final Rule, the CKD exemption would still be in effect. The Agency believes that
many of the affected facilities would utilize the time to adopt pollution prevention technologies
which would reduce, if not- eliminate, the amount of hazardous CKD they generate or stop
burning hazardous waste.
Under this option, on-site CKD management practices at those facilities with dust that
exhibited any of the RCRA hazardous waste characteristics, or CKD derived from the burning of
listed hazardous wastes (see 40 CFR 261.3(c)(2)(i)) would be affected by the provisions of RCRA
Subtitle C. CKD disposal piles which are inactive on or before the effective date of the Final
Rule would be unaffected by the provisions of Subtitle C, unless subsequently managed.
Those facilities that do not burn hazardous waste would not generally be affected by
removing the exemption unless they generated characteristic RCRA hazardous waste. The
Agency expects the number of non-hazardous waste burning facilities affected by this option
would be small, since CKD rarely exhibits a characteristic of hazardous waste. These facilities
would have an incentive to control their cement manufacturing process to avoid generating
characteristic CKD.
Option 4: Remove the CKD Exemption, and rely on existing hazardous waste rules to
control cement kiln dust.
This option is similar to Option 3, except the exemption would be removed in accordance
with RCRA §3010(b). (Under Subtitle C of RCRA, wastes brought under regulatory control
have up to six months from the Regulatory Determination before they become subject to
hazardous waste control.) Thus, CKD that is hazardous v/aste-derived or exhibits a RCRA
hazardous characteristic would be made subject to the provisions of RCRA Subtitle C.
Otherwise, this option is the same as Option 3.
Option 5: Promulgate Regulatory Standards for the Management of CKD Waste.
As described above, the likely regulatory result under Options 3 and 4 would be to make
CKD generated by a kiln that burns listed hazardous wastes itself, a hazardous waste under the
derived-from rule (40 CFR 261.3(c)(2)(i)). The indirect fbodchain risks potentially identified in
this Report, however, are not associated only with CKD generated by hazardous waste burning
kilns. As a result, EPA is also considering regulatory mechanisms that would specifically address
these risks, including promulgating regulatory standards under Subtitle C for the management of
CKD waste that would provide adequate protection against these risks.
RCRA §3001(b)(3)(C) provides that EPA shall within six months of the RTC "determine
to promulgate regulations under this subchapter...or determine that such regulations are
unwarranted." The statute does not describe the type of regulation that EPA should consider
promulgating (if any), other than that such regulation be under Subtitle C of RCRA. EPA could
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promulgate minimally burdensome management standards for cement kiln; dust that would
adequately control the indirect foodchain risks, such as: (1) requiring that dust piles be kept
covered to control fugitive emissions and institute surface water run-off and erosion controls; (2)
maintaining ground-water protection, perhaps by requiring that CKD piles be maintained on a
non-earthen base or by requiring a liner; and (3) establishing risk-based concentration thresholds
for all constituents of concern (including 2,3,7,8-TCDD, arsenic^ cadmium; and lead) for CKD
used as a direct soil amendment. Additional or alternative standards may be appropriate, and
EPA welcomes comments and suggestions on this aspect of its options. ;
Of the five options being considered by the Agency, Options 3, 4 and 5 would provide
more control through implementation of the provisions of Subtitle C. The principal difference
between Options 3 and 4 is the timing of the implementation of the regulatory controls. Option 3
provides industry additional time to implement waste minimization/pollution prevention options
and more protective CKD management standards. Option 4 would bring CKD under Subtitle C
regulatory control more quickly. Removing the exemption also would impose regulatory equity
between CKD generated from kilns that burn RCRA hazardous waste and residues from other
incinerators that burn RCRA hazardous waste that do not have such an exemption. Option 5
would provide management standards to control all CKD, and would be targeted to specifically
address only those risks of potential concern.
The Agency did not evaluate the risk from the land application of agricultural lime, so it
cannot determine whether there is an increase in incremental risk when CKD is substituted. In
any event, CKD-sewage sludge derived fertilizers and soil amendments are considered safe for
such uses as fertilizer and pose minimal risk because these final products are required to be tested
to assure they comply with all provisions of 40 CFR 503, which are fully protective of human
health and the environment. It should be noted that if the exemption is removed, fertilizer that is
derived from CKD generated from a kiln that burns listed hazardous waste is itself a hazardous
waste under the derived-from rule (40 CFR 261.3(e)(2)(i)); the extent of regulation, however, is
limited (see 40 CFR 266,20(b)).
In addition, it should also be noted that under current rules, if CKD is recycled, the
resulting clinker is not automatically subject to the provisions of Subtitle C. By removing the
exemption, however, clinker may be affected by the derived-from rule (40 CFR..261.3(c)(2)(i)) if
the kiln burns listed hazardous waste, thereby becoming a hazardous waste. The Agency has not
yet fully analyzed available data on trace constituents in clinker. Based 01 our understanding of
current data, however, the Agency does not believe that clinker produced from kilns that burn
listed hazardous waste generally poses a hazard to human health and the environment.
4,0 Next Steps
This report will be subject to a 45 day comment period and a public hearing in
Washington, D.C., so that the Agency can receive public comment. After an evaluation of public
comments on this Report to Congress, the Agency will, in accordance with RCRA
§3001(b)(3)(C), reach a final Regulatory Determination on the management status of CKD within
six months of submission of this Report. The Regulatory Determination requires the Agency only
to determine to promulgate regulations under Subtitle C, or determine that Subtitle C is
unwarranted. Thus, if RCRA §3004(x) or Option 5 is chosen, EPA would have time beyond six
months to promulgate a Final Rule.
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