difficult to establish. EPA could establish a minimum national
requirement, but to do so, EPA would need to establish the most
restrictive criteria that would ensure protection of the most
vulnerable site conditions. Because this would result in overregulation
of less vulnerable sites, EPA questions whether such a restrictive
approach would be consistent with the RCRA section 4004 standard of
ensuring ``no reasonable probability of adverse effects.'' (emphasis
added). The existing 40 CFR part 258 requirements provide the
flexibility to address this issue by establishing alternate performance
standards and relying on the oversight resulting from state permitting
processes, and supported by EPA approval of state plans. Indeed, EPA
made clear in the final MSWLF rule that this was the reason that
several of the individual performance standards in the existing 40 CFR
part 258 requirements are available only in states with EPA approved
programs. See, e.g., 56 FR 51096 (authorizing alternative cover
designs). However, EPA cannot rely on these oversight mechanisms to
implement the RCRA 4004 subtitle D requirements. Under these provisions
of RCRA, EPA lacks the authority to require state permits, approve
state programs, and to enforce the criteria. Moreover as discussed in
Section IV, the level of state oversight varies appreciably among
states. Consequently, for these provisions EPA is also proposing to
require the owner or operator of the facility to obtain certifications
by independent registered professional engineers to provide
verification that these provisions are properly applied. EPA has also
proposed to require certifications by independent professional
engineers more broadly as a mechanism to facilitate citizen oversight
and enforcement. As discussed in greater detail below, EPA is proposing
to require minimum qualifications for the professionals who are relied
upon to make such certifications. In general, EPA expects that
professionals in the field will have adequate incentive to provide an
honest certification, given that the regulations require that the
engineer not be an employee of the owner or operator, and that they
operate under penalty of losing their license.
    EPA believes that these provisions allow facilities the flexibility
to account for site conditions, by allowing them to deviate from the
specific technical criteria, provided the alternative meets a specified
performance standard, yet also provide some degree of third-party
verification of facility practices. The availability of meaningful
independent verification is critical to EPA's ability to conclude that
these performance standards will meet the RCRA section 4004
protectiveness standard. EPA recognizes that relying upon third party
certifications is not the same as relying upon the state regulatory
authority, and will likely not provide the same level of
``independence.'' For example, although not an employee, the engineer
will still have been hired by the utility. EPA therefore broadly
solicits comment on whether this approach provides the right balance
between establishing sufficient guarantee that the regulations will be
protective, and offering facilities sufficient flexibility to be able
to feasibly implement requirements that will be appropriate to the site
conditions. In this regard, EPA would also be interested in receiving
suggestions for other mechanisms to provide facility flexibility and/or
verification.
    There is a broad range of the extent to which states already have
some of these requirements in place under their current RCRA subtitle D
waste management programs established under state law, as explained
previously in this preamble. EPA and certain commenters, however, have
identified significant gaps in state programs and current practices.
For example, EPA does not believe that many, if any, states currently
have provisions that would likely cause the closure of existing surface
impoundments, such as the provisions in today's proposed rule that
surface impoundments must either retrofit to meet all requirements,
such as installing a composite liner, or stop receiving CCRs within a
maximum of five years of the effective date of the regulation. The RCRA
subtitle D proposal outlined here is intended to fill such gaps and
ensure national minimum standards. EPA intends to provide a complete
set of requirements, designed to ensure there will be no reasonable
probability of adverse effects on health or the environment caused by
CCR landfills or surface impoundments. EPA's co-proposed RCRA subtitle
D minimum criteria are discussed below.
2. Notifications
    In response to EPA's lack of authority to require a state permit
program or to oversee state programs, EPA has sought to enhance the
protectiveness of the proposed RCRA subtitle D standards by providing
for state and public notifications of the third party certifications,
as well as other information that documents the decisions made or
actions taken to comply with the performance criteria. As discussed in
the section-by-section analysis below, documentation of how the various
standards are met must be placed in the operating record and the state
notified.
    The owner or operator must also maintain a web site available to
the public that contains the documentation that the standard is met.
EPA is proposing that owners and operators provide notification to the
public by posting notices and relevant information on an internet site
with a link clearly identified as being a link to notifications,
reports, and demonstrations required under the regulations. EPA
believes the internet is currently the most convenient and widely
accessible means for gathering information and disseminating it to the
public. However, the Agency solicits comments regarding the methods for
providing notifications to the public and the states. EPA also solicits
comments on whether there could be homeland security implications with
the requirement to post information on an internet site and whether
posting certain information on the internet may duplicate information
that is already available to the public through the state.
    The co-proposed subtitle D regulation accordingly includes a number
of public notice provisions. In particular, to ensure that persons
residing near CCR surface impoundments are protected from potential
catastrophic releases, we are proposing that when a potentially
hazardous condition develops regarding

the integrity of a surface impoundment, that the owner or operator
immediately notify potentially affected persons and the state. The
Agency is also proposing to require that owners or operators notify the
state, and place the report and other supporting materials in the
operating record and on the company's internet site of various
demonstrations, documentation, and certifications. Accordingly, notice
must be provided: (1) Of demonstrations that CCR landfills or surface
impoundments will not adversely affect human health or the environment;
(2) of demonstrations of alternative fugitive dust control measures;
(3) annually throughout the active life and post-closure care period
that the landfill or surface impoundment is in compliance with the
groundwater monitoring and corrective action provisions; (4) when
documentation related to the design, installation, development, and
decommission of any monitoring wells, piezometers and other
measurement, sampling, and analytical devices has been placed in the
operating record; (5) when certification of the groundwater monitoring
system by an independent registered professional engineer or
hydrologist has been placed in the operating record; (6) when
groundwater monitoring sampling and analysis program documentation has
been placed in the operating record; (7) when the use of an alternative
statistical method is to be used in evaluating groundwater monitoring
data and a justification for the alternative statistical method has
been placed in the operating record; (8) when the owner or operator
finds that there is a statistically significant increase over
background for one or more of the constituents listed in Appendix III
of the proposed rule, at any groundwater monitoring well; (9) when a
notice of the results of assessment monitoring that may be required
under the groundwater monitoring program is placed in the operating
record; (10) when a notice is placed in the operating record that
constituent levels that triggered assessment monitoring have returned
to or below background levels; (11) when a notice of the intent to
close the unit has been placed in the operating record; and (12) when a
certification, signed by an independent registered professional
engineer verifying that post-closure care has been completed in
accordance with the post-closure plan, has been placed in the operating
record. Please consult the proposed subtitle D regulation provided with
this notice for all the proposed notification and documentation
requirements.
    As explained earlier, the RCRA subtitle D approach relies on state
and citizen enforcement. EPA believes that it cannot conclude that the
RCRA subtitle D regulations will ensure there is no reasonable
probability of adverse effects on health or the environment, unless
there is a mechanism for states and citizens to monitor the situation,
such as when groundwater monitoring shows exceedances, so that they can
determine when intervention is appropriate. EPA also believes that
notifications, such as those described above, will minimize the danger
of owners or operators abusing the self-implementing system through
increased transparency and by facilitating the citizen suit enforcement
mechanism.
    EPA is proposing that owners and operators provide notification to
the public by posting notices and relevant information on an internet
site with a link clearly identified as being a link to notifications,
reports, and demonstrations required under the regulations. EPA
believes the internet is currently the most convenient and widely
accessible means for gathering information. However, the Agency
solicits comments regarding the methods for providing notifications to
the public and the states.

B. Section-by-Section Discussion of RCRA Subtitle D Criteria

1. Proposed Modifications to Part 257, Subpart A
    EPA is proposing to modify the existing open dumping criteria found
in 40 CFR 257.1, Scope and Purpose, to recognize the creation of a new
subpart D, which consolidates all of the criteria adopted for
determining which CCR Landfills and CCR Surface impoundments pose a
reasonable probability of adverse effects on health or the environment
under sections 1008(a)(3) and 4004(a) of the Act. Facilities and
practices failing to satisfy these consolidated subpart D criteria
violate RCRA's prohibition on open dumping. The proposed regulation
also excludes CCR landfills and surface impoundments subject to
proposed subpart D from subpart A, except as otherwise provided in
subpart D.
    In general, these provisions are intended to integrate the new
requirements with the existing open dumping criteria, and have only
been modified to clarify that the proposed RCRA subtitle D regulations
define which CCR landfills and surface impoundments violate the federal
standards, and therefore may be enforced by citizen suit under RCRA
4005(a) and 7002. EPA has also proposed language to make clear that
those CCR landfills and surface impoundments that are subject to the
new proposed Subpart D would not also be subject to Subpart A, with the
exception of three of the existing Subpart A criteria (257.3-1,
Floodplains, 257.3-2 Endangered Species, 257.3-3 Surface water) that
would continue to apply to these facilities. The applicability of these
three provisions to CCR disposal facilities is discussed later in this
preamble.
    Finally, EPA also notes that its intent in excluding CCR landfills
and surface impoundments from 40 CFR 257 Subpart A in this manner is to
consolidate the requirements applicable to those particular facilities
in one set of RCRA subtitle D regulations. EPA does not intend to
modify the coverage of 40 CFR 257 subpart A as to other disposal
facilities and practices for CCRs, such as beneficial uses of CCRs when
they are applied to the land used for food-chain crops. It is EPA's
intent that such activities would continue to be subject to the
existing criteria under Subpart A.
2. General Provisions
    The proposed general provisions address the applicability of the
new proposed RCRA Subpart D requirements, the continuing applicability
of certain of the existing open dumping criteria, provide for an
effective date of 180 days after promulgation, and define key terms for
the proposed criteria.
    Applicability. The applicability provisions identify those solid
waste disposal facilities subject to the new proposed RCRA Subpart D
(i.e., CCR landfills and CCR surface impoundments as defined under
proposed 257.40(b)). The applicability section also identifies three of
the existing subpart A criteria that would continue to apply to these
facilities: 257.3-1, Floodplains, 257.3-2 Endangered Species, 257.3-3
Surface water. The applicability of these provisions to CCR disposal
facilities is discussed later in this preamble.
    The applicability section also specifies an effective date of 180
days after publication of the final rule. EPA believes that, with the
specific exceptions discussed below, this time frame strikes a
reasonable balance between the time that owners and operators of CCR
units would need in order to come into compliance with the rule's
requirements, and the need to implement the proposed requirements in a
timeframe that will maximize protection of health and the environment.
We note that 180 days is

the timeframe for persons to come into compliance with most of the
requirements under RCRA subtitle C, and believe that if persons can
meet the hazardous waste provisions within this time period under RCRA
subtitle C, that it is reasonable to conclude that persons should be
able to meet those same or similar requirements under RCRA subtitle D.
EPA also notes that pending finalization of any regulations, facilities
continue to be subject to the existing part 257 open dumping criteria
as they may apply.
3. Definitions
    This section of the proposed regulation discusses the definitions
of some of the key terms used in the proposed RCRA subtitle D rule that
are necessary for the proper interpretation of the proposed criteria.
Because EPA is creating a separate section of the regulations specific
to CCR units, EPA is also consolidating the existing definitions in
this section. However, by simply incorporating these unmodified
definitions into this new section of the regulations, EPA is not
proposing to reopen, or soliciting comments on these requirements. Nor,
for definitions where the only modification relates to an adjustment
specific to CCRs, is EPA proposing to revise or reopen the existing
part 257 or part 258 definitions as they apply to other categories of
disposal facilities, as those will remain unaltered. Accordingly, EPA
will not respond to any comments on these definitions.
    Aquifer. EPA has defined aquifer for this proposal as a geologic
formation, group of formations, or portion of a formation capable of
yielding significant quantities of ground water to wells or springs.
This is the same definition currently used in EPA's hazardous waste
program and MSWLF criteria in 40 CFR 258.2 and differs from the
original criteria definition (40 CFR 257.3-4(c)(1)) only in that it
substitutes the term ``significant'' for ``usable.'' The Agency is
proposing to adopt the modified definition to make the subtitle C and
subtitle D alternatives consistent.
    Coal Combustion Residuals (CCRs) means fly ash, bottom ash, boiler
slag, and flue gas desulfurization wastes. CCRs are also known as coal
combustion wastes (CCWs) and fossil fuel combustion (FFC) wastes.
    CCR Landfill. The co-proposed criteria includes a definition of
``CCR landfill'' to mean an area of land or an excavation, including a
lateral expansion, in which CCRs are placed for permanent disposal, and
that is not a land application unit, surface impoundment, or injection
well. For purposes of this proposed rule, landfills also include piles,
sand and gravel pits, quarries, and/or large scale fill operations. EPA
modeled this definition after the definition of ``Municipal solid waste
landfill (MSWLF) unit'' contained in the existing criteria for those
facilities. Although this is somewhat different than the definition
proposed under the subtitle C alternative (which is based on the
existing part 260 definition), EPA intends for this proposed definition
to capture those landfills and other large-scale disposal practices
that are described in EPA's damage cases and risk assessments discussed
in sections II, VI, and the RIA.
    CCR Surface Impoundment. EPA has proposed to define this term to
mean a facility or part of a facility, including a lateral expansion,
that is a natural topographic depression, human-made excavation, or
diked area formed primarily of earthen materials (although it may be
lined with human-made materials), that is designed to hold an
accumulation of liquid CCR wastes or CCR wastes containing free liquids
and that is not an injection well. EPA has included as examples of
surface impoundments settling and aeration pits, ponds, and lagoons.
This is the same definition that EPA is proposing as part of the
subtitle C alternative, and is generally consistent with the definition
of ``surface impoundment or impoundment'' contained in the existing
257.2 criteria.
    EPA further proposes in the definition a description of likely
conditions at a CCR surface impoundment, stating that CCR surface
impoundments often receive CCRs that have been sluiced (flushed or
mixed with water to facilitate movement), or wastes from wet air
pollution control devices. EPA intends for this proposed definition to
capture those surface impoundments that are described in EPA's damage
cases and risk assessments described in sections II, VI, and the RIA.
    Existing CCR Landfill/Existing CCR Surface Impoundment. EPA has
included a proposed definition of this term to mean a CCR landfill or
surface impoundment, which was in operation on, or for which
construction commenced prior to the effective date of the final rule.
The proposed definition states that a CCR landfill or surface
impoundment has commenced construction if: (1) The owner or operator
has obtained the Federal, State and local approvals or permits
necessary to begin physical construction; and (2) either (i) a
continuous on-site, physical construction program has begun; or (ii)
the owner or operator has entered into contractual obligations--which
cannot be cancelled or modified without substantial loss--for physical
construction of the CCR landfill or surface impoundment to be completed
within a reasonable time. These definitions are identical to the co-
proposed subtitle C definitions, described in section VI. EPA sees no
reason to establish separate definitions of these units for purposes of
RCRA subtitle D since the question of whether these units are existing
should not differ between whether they are regulated under RCRA
subtitles C or D.
    Factor of Safety (Safety Factor). The proposed definition is the
ratio of the forces tending to resist the failure of a structure to the
forces tending to cause such failure as determined by accepted
engineering practice. This definition is the same as the co-proposed
subtitle C definitions, described in section VI. EPA sees no reason to
establish a separate definition for this term for purposes of RCRA
subtitle D since the question of ``Factor of safety'' should not differ
between units that would be regulated under RCRA subtitles C or D.
    Hazard potential classification. This term is proposed to be
defined as the possible adverse incremental consequences that result
from the release of water or stored contents due to failure of a dam
(or impoundment) or misoperation of the dam or appurtenances.
    The proposed definition further delineates the classification into
four categories:

--High hazard potential surface impoundment which is a surface
impoundment where failure or misoperation will probably cause loss of
human life;
--Significant hazard potential surface impoundment which is a surface
impoundment where failure or misoperation results in no probable loss
of human life, but can cause economic loss, environmental damage,
disruption of lifeline facilities, or impact other concerns; and
--Low hazard potential surface impoundment means a surface impoundment
where failure or mis-operation results in no probable loss of human
life and low economic and/or environmental losses. Losses are
principally limited to the surface impoundment owner's property.
--Less than low hazard potential surface impoundment means a surface
impoundment not meeting the definitions for High, Significant, or Low
Hazard Potential.

    This definition, just like the proposed RCRA subtitle C definition,
follows the

Hazard Potential Classification System for Dams, developed by the U.S.
Army Corps of Engineers for the National Inventory of Dams. This system
is a widely-used definitional scheme for classifying the hazard
potential posed by dams, and EPA expects that the regulated community's
familiarity with these requirements will make their application to CCR
surface impoundments relatively straightforward.
    Independent registered professional engineer or hydrologist. This
term is defined as a scientist or engineer who is not an employee of
the owner or operator of a CCR landfill or surface impoundment who has
received a baccalaureate or post-graduate degree in the natural
sciences or engineering and has sufficient training and experience in
groundwater hydrology and related fields as may be demonstrated by
state registration, professional certifications, or completion of
accredited university programs that enable that individual to make
sound professional judgments regarding groundwater monitoring,
contaminant fate and transport, and corrective action.
    Because the proposed RCRA subtitle D requirements cannot presuppose
the existence of a permit or state regulatory oversight, the criteria
in today's proposed rule are self-implementing. However, as discussed
earlier, to try to minimize the potential for overregulation, and to
provide some degree of flexibility, EPA is proposing to allow
facilities to deviate from the criteria upon a demonstration that the
alternative meets a specified performance standard. But to provide for
a minimum level of verification and to reduce the opportunity for
abuse, the Agency believes it is imperative to have an independent
party review, and certify the facility's demonstrations. The Agency
also believes that those professionals certifying the requirements of
today's proposed rule should meet certain minimum qualifications. The
Agency is proposing to define a ``qualified ground-water scientist'' to
be a scientist or engineer who has received a baccalaureate or post-
graduate degree in the natural sciences or engineering and has
sufficient training and experience in ground-water hydrology and
related fields as may be demonstrated by State registration,
professional certification, or completion of accredited university
programs that enable that individual to make sound professional
judgments regarding ground-water monitoring, contaminant fate and
transport, and corrective action. This requirement is the same as the
current requirement at Sec.  258.50(f). The Agency believes that
specialized coursework and training should include, at a minimum,
physical geology, ground-water hydrology or hydrogeology, and
environmental chemistry (e.g., soil chemistry or low temperature
geochemistry). Some national organizations, such as the American
Institute of Hydrology and the National Water Well Association,
currently certify or register ground-water professionals. States may of
course establish more stringent requirements for these professionals,
including mandatory licensing or certification. As discussed above, EPA
seeks comment on the proposed reliance on independent professionals in
implementing the proposed flexibility of performance standards.
    Lateral expansion means a horizontal expansion of the waste
boundaries of an existing CCR landfill, or existing CCR surface
impoundment made after the effective date of the final rule. This
definition is identical to the co-proposed subtitle C definition,
described in section VI. EPA sees no reason to establish a separate
definition of this term for purposes of RCRA subtitle D since whether a
lateral expansion has occurred at a CCR landfill or surface impoundment
should not differ between those units regulated under RCRA subtitles C
or D.
    New CCR landfill means a CCR landfill from which there is placement
of CCRs without the presence of free liquids, which began operation, or
for which the construction commenced after the effective date of the
rule. This definition is identical to the co-proposed subtitle C
definition, described in section VI. EPA sees no reason to establish a
separate definition for this term for purposes of RCRA subtitle D since
whether a landfill is new should not differ between those landfills
that are regulated under RCRA subtitles C or D.
    New CCR surface impoundment means a CCR surface impoundment into
which CCRs with the presence of free liquids have been placed, which
began operation, or for which the construction commenced after the
effective date of the rule. EPA sees no reason to establish a separate
definition for this term for purposes of RCRA subtitle D since whether
a surface impoundment is new should not differ between those surface
impoundments that are regulated under RCRA subtitles C or D.
    Recognized and generally accepted good engineering practices means
engineering maintenance or operation activities based on established
codes, standards, published technical reports, recommended practice, or
similar document. Such practices detail generally approved ways to
perform specific engineering, inspection, or mechanical integrity
activities. In several provisions, EPA requires that the facility
operate in accordance with ``recognized and generally accepted good
engineering practices,'' or requires an independent engineer to certify
that a design or operating parameter meets this standard. The
definition references but does not attempt to codify any particular set
of engineering practices, but to allow the professional engineer
latitude to adopt improved practices that reflect the state-of-the art
practices, as they develop over time. This definition is the same as
the definition EPA is proposing under the subtitle C alternative.
4. Location Restrictions
    To provide for no reasonable probability of adverse effects on
health or the environment from the disposal of CCRs at CCR landfills
and surface impoundments, EPA believes that any RCRA subtitle D
regulation would need to ensure that CCR disposal units were
appropriately sited. The proposed location restrictions include
requirements relating to placement of the CCRs above the water table,
wetlands, fault areas, seismic impact zones, and unstable areas. In
addition, as previously noted, the location standards in subpart A of
40 CFR part 257 for floodplains, endangered species, and surface waters
would also continue to apply. Finally, the proposed regulations also
address the closure of existing CCR landfills and surface impoundments.
    The location standards in this proposal are primarily based on the
location standards developed for municipal solid waste landfill units,
and represent provisions to ensure that the structure of the disposal
unit is not adversely impacted by conditions at the site, or that the
location of a disposal unit at the site would not increase risks to
human health or the environment. The criteria for municipal solid waste
landfills provide restrictions on siting units in wetlands, fault
areas, seismic impact zones, and unstable areas.\151\

Each of those factors is generally recognized as having the potential
to impact the structure of a disposal unit negatively or increase the
risks to human health and the environment. As discussed below in more
detail, each of these provisions adopted for today's RCRA subtitle D
co-proposal relies in large measure, on the record EPA developed to
support the 40 CFR part 258 municipal solid waste landfill criteria.
EPA's Guide for Industrial Waste Management (EPA530-R-03-001, February
2003) also identifies these location restrictions as appropriate for
industrial waste management. These proposed requirements are all
discussed in turn below, after a general explanation of the Agency's
proposed treatment of new CCR disposal units compared to existing CCR
disposal units.
---------------------------------------------------------------------------

    \151\ The proposed definition of seismic impact zone was
modified from the part 258 definition as explained in the
``Discussion of Individual Location Requirements'' section below.
The part 258 criteria also include location restrictions relating to
airport safety and floodplains, in 258.10 and 258.11, respectively.
EPA has not proposed an analogue to 258.10 because the hazard
addressed by that criterion, bird strikes to aircraft, is
inapplicable in the context of CCR disposal units, which do not tend
to attract birds to them. As discussed in the main text, EPA is
proposing to maintain the existing criterion in 257, subpart A for
floodplains.
---------------------------------------------------------------------------

    a. Differences in Location Restrictions for Existing and New CCR
Landfills and Surface Impoundments, and Lateral Expansions. EPA is
proposing different sets of location restrictions under the Subtitle D
approach, depending on whether a unit is a CCR landfill or surface
impoundment, and whether it is an existing or new unit. Lateral
expansions fall within the definitions of new units, and are treated
accordingly.
    While new landfills would be required to comply with all of the
location restrictions, EPA is proposing to subject existing landfills
to only two of the location restrictions--floodplains, and unstable
areas--in today's rule. Existing landfills are already subject to the
floodplains location restriction because it is contained in the
existing 40 CFR part 257, subpart A criteria, which have been in effect
since 1979. Because owners and operators of existing landfills already
should be in compliance with this criterion, applying this location
restriction will have no impact to the existing disposal capacity,
while continuing to provide protection of human health and the
environment.
    The Agency decided to apply today's final unstable area location
restriction to existing CCR landfills, because the Agency believes that
the impacts to human health and the environment that would result from
the rapid and catastrophic destruction of these units outweighs any
disposal capacity concerns resulting from the closure of existing CCR
disposal units.
    On the other hand EPA is not proposing to impose requirements on
existing CCR landfills in wetlands, fault areas, or seismic impact
areas. We base this decision on the possibility that a significant
number of CCR landfills may be located in areas subject to this
requirement. The Agency believes that such landfills pose less risks
and are structurally less vulnerable than surface impoundments, and
disposal capacity shortfalls, which could result if existing CCR
landfills in these locations were required to close, raise greater
environmental and public health concerns than the potential risks
caused by existing units in these locations. For example, if existing
CCR landfills located in wetlands were required to close, there would
be a significant decrease in disposal capacity, particularly given the
Agency's expectation that many existing surface impoundments will
choose to close, in response to this proposed rule. In addition,
wetlands are more prevalent in some parts of the country (e.g., Florida
and Louisiana). In these States, the closure of all existing CCR
landfills located in wetlands could potentially significantly disrupt
statewide solid waste management. Therefore, the Agency believes that
it may be impracticable to require the closure of existing CCR
landfills located in wetlands. However, EPA seeks comment and
additional information regarding the number of existing CCR landfills
that are located in such areas.
    Concern about impacts on solid waste disposal capacity as well as
the lower level of risks and the structural vulnerability of landfills,
as compared to surface impoundments, were also the primary reasons the
Agency is not proposing to subject existing CCR landfills to today's
proposed fault area location restrictions. The closure of a significant
number of existing CCR landfills located in fault areas could result in
a serious reduction of CCR landfill capacity in certain regions of the
U.S. where movement along Holocene faults is common, such as along the
Gulf Coast and in much of California and the Pacific Northwest. The
Agency, however, does not have specific data showing the number of
units and the distance between these disposal units and the active
faults, and therefore, is unable to precisely estimate the number of
these existing CCR landfills that would not meet today's fault area
restrictions. EPA therefore solicits comment and additional data and
information regarding the extent to which existing CCR landfills are
currently located in such locations. However, given the potential for
impacts on solid waste capacity and the lower levels of risk associated
with landfills compared to surface impoundments, EPA has concluded that
it may not be appropriate to subject existing CCR landfills to the
proposed fault area requirements.
    Similarly, the Agency is not proposing to impose the seismic impact
zone restrictions on existing CCR landfills located in these areas. As
with the other location restrictions, the Agency anticipates that a
significant number of existing CCR disposal units are located in these
areas. EPA is concerned that such facilities would be unable to meet
the requirements, because retrofitting would be prohibitively expensive
and technically very difficult in most cases, and would therefore be
forced to close.
    EPA generally seeks comment and additional information regarding
the extent to which CCR landfill capacity would be affected by applying
these location restrictions to existing CCR landfills. Information on
the prevalence of existing CCR landfills in such areas would be of
particular interest to the Agency. EPA also notes that the proposed
location requirements do not reflect a complete prohibition on siting
facilities in such areas, but provide a performance standard that
facilities must meet in order to site a unit in such a location. EPA
therefore solicits comment on the extent to which facilities could
comply with these performance standards, and the necessary costs that
would be incurred to retrofit the unit to meet these standards.
    As discussed earlier in this preamble, this proposed approach is
generally consistent with the proposed approach to existing landfills
under subtitle C of RCRA, and with Congressional distinctions between
the risks presented by landfills and surface impoundments. Existing
landfills that are brought into the hazardous waste system because they
are receiving newly listed hazardous wastes are not generally required
to be retrofitted with a new minimum-technology liner/leachate
collection and removal system (or to close), and they would not be
subject to such requirements under today's proposal. EPA sees no reason
or special argument to adopt more stringent requirements under the co-
proposed subtitle D criteria for CCR landfills, particularly given the
volume of the material and the disruption that could be involved if
these design requirements were applied to existing landfills.
    By contrast, and consistent with its approach to existing surface
impoundments under subtitle C, the proposed regulations would apply all
of the location restrictions to existing surface impoundments. This
means that facilities would need to either

demonstrate that the surface impoundment meets the performance standard
that serves as the alternative to the prohibition, retrofit the unit so
that it can meet the performance standard, or close. EPA is making this
distinction because, as discussed in sections IV-VI, the record
indicates that the risks associated with CCR surface impoundments are
substantially higher than the risks posed by CCR landfills. The impacts
to human health and the environment that would result from the rapid
and catastrophic destruction of these units could result in injuries to
human health and the environment, that are far more significant, as
illustrated by the impacts of the recent TVA spill in Tennessee. The
risks to human health and the environment of such a catastrophic
collapse far outweigh the costs of requiring surface impoundments to
retrofit or close. Moreover, there are significant economic costs
associated with the failure of a surface impoundment; as noted earlier,
the direct cost to clean up the TVA spill is currently estimated to
exceed one billion dollars. Surface impoundments also are more
vulnerable to structural problems if located in unstable areas, fault
areas and seismic impact areas. Finally, as already noted, the
distinction EPA is making between existing landfills and existing
surface impoundments is also consistent with Congressional direction;
as discussed in section VI, Congress specifically required existing
surface impoundments receiving hazardous wastes to retrofit to meet the
new statutory requirements or to close, in direct contrast to their
treatment of existing landfills.
    Although many surface impoundments may close as a result of these
requirements, EPA believes that it is proposing to take a number of
actions to alleviate concerns that this will present significant
difficulties with regard to disposal capacity in the short-term: e.g.,
``grandfathering'' in existing CCR landfills, allowing CCR landfills to
vertically expand without retrofitting, and delayed implementation
dates. At the same time, as discussed in greater detail in section VI,
with regard to the subtitle C co-proposal, EPA is soliciting comment on
the appropriate amount of time necessary to meet these time frames as
well as measures that could help to address the potential for
inadequate disposal capacity. EPA notes, however, that unlike under the
subtitle C co-proposal, EPA is not proposing to require facilities to
cease wet handling. Thus EPA expects that both the impacts and the time
frames needed for facilities to come into compliance would be lower.
    While the proposed requirements relating to the placement above the
water table, wetlands, fault areas, and seismic impact zones would not
apply to existing CCR disposal units, all of these restrictions apply
to lateral expansions of existing CCR disposal units, as well as new
CCR disposal units. Therefore, under the proposal, owners and operators
of existing CCR landfills could vertically expand their existing
facilities in these locations, but must comply with the provisions
governing new units if they wish to laterally expand. EPA expects that
allowing such vertical expansion will allow for increased capacity,
which will be particularly important, if, as EPA expects, many surface
impoundments would close, should this regulation be adopted. At the
same time, EPA believes that the risks to human health or the
environment will be mitigated because facilities will be required to
otherwise comply with the more stringent environmental restrictions,
such as the corrective action and closure provisions proposed below.
b. Discussion of Individual Location Requirements
    Placement above the water table. The co-proposed subtitle D
regulations would prohibit new CCR landfills and all surface
impoundments from being located within two feet of the upper limit of
the natural water table. EPA is proposing to define the natural water
table as the natural level at which water stands in a shallow well open
along its length and penetrating the surficial deposits just deeply
enough to encounter standing water at the bottom. This is the level of
water that exists, when uninfluenced by groundwater pumping or other
engineered activities.
    Floodplains. CCR landfills and surface impoundments are currently
subject to the open dumping criteria contained in 40 CFR 257, Subpart
A. These minimum criteria include restrictions on floodplain impacts
under 257.3-1. As facilities should already be complying with this
requirement, EPA is not proposing to modify it as part of today's rule.
Accordingly, EPA is not reopening this requirement.
    Wetlands. The regulations require that the facility prepare and
make available a written demonstration that such engineering measures
have been incorporated into the unit's design to mitigate any potential
adverse impact, and require certification by an independent registered
professional engineer either that the new CCR disposal unit is not in a
prohibited area, as defined by the regulation, or that the
demonstration meets the regulatory standards.
    Today's proposed wetland provisions would apply only to new CCR
landfills, including lateral expansions of existing CCR disposal units,
and all surface impoundments. New CCR landfills, which include lateral
expansions, as well as all surface impoundments, are barred from
wetlands unless the owner or operator of the disposal unit can make the
following demonstrations certified by an independent registered
professional engineer or hydrologist. First, the owner or operator must
rebut the presumption that a practicable alternative to the proposed
CCR disposal unit or lateral expansion is available that does not
involve wetlands. Second, the owner or operator must show that the
construction or operation of the unit will not cause or contribute to
violations of any applicable State water quality standard, violate any
applicable toxic effluent standard or prohibition, jeopardize the
continued existence of endangered or threatened species or critical
habitats, or violate any requirement for the protection of a marine
sanctuary. Third, the owner or operator must demonstrate that the CCR
disposal unit or lateral expansion will not cause or contribute to
significant degradation of wetlands. To this end, the owner or operator
must ensure the integrity of the CCR disposal unit, and its ability to
protect ecological resources by addressing: erosion, stability, and
migration potential of native wetland soils, muds and deposits used to
support the unit; erosion, stability, and migration potential of
dredged and fill materials used to support the unit; the volume and
chemical nature of the CCRs; impacts on fish, wildlife, and other
aquatic resources and their habitat from release of CCRs; the potential
effects of catastrophic release of CCRs to the wetland and the
resulting impacts on the environment; and any additional factors, as
necessary, to demonstrate that ecological resources in the wetland are
sufficiently protected. Fourth, the owner or operator must demonstrate
that steps have been taken to attempt to achieve no net loss of
wetlands by first avoiding impacts to wetlands to the maximum extent
practicable, then minimizing unavoidable impacts to the maximum extent
practicable, and finally offsetting remaining unavoidable wetland
impacts through all appropriate and practicable compensatory mitigation
actions. The owner or operator must place the demonstrations in the
operating record and the

company's Internet site, and notify the state that the demonstrations
have been placed in the operating record.
    For facilities that cannot make such a demonstration, this proposed
provision effectively bans the siting of new CCR landfills or surface
impoundments in wetlands, and would require existing surface
impoundments to close.
    EPA notes that this section of the proposal is consistent with
regulatory provisions currently governing the CWA section 404 program,
including the definition of wetlands contained in proposed 257.61. See
40 CFR 232.2(r). EPA believes that wetlands are very important, fragile
ecosystems that must be protected, and has identified wetlands
protection as a top priority. Nevertheless, EPA has proposed to
continue to allow existing CCR landfills to be sited in wetlands to
minimize the disruption to existing CCR disposal facilities, as it is
EPA's understanding that many existing CCR landfills are located near
surface water bodies, in areas that also may qualify as wetlands under
the proposed criteria. Likewise, EPA is concerned that an outright ban
of new CCR landfills in wetlands would severely restrict the available
sites or expansion possibilities, given that EPA is proposing to impose
other conditions on surface impoundments that may cause many to
ultimately close. As noted in section VI, concerns have been raised
regarding the potential for disposal capacity shortfalls, which could
lead to other health and environmental impacts, such as the
transportation of large volumes of CCRs over long distances to other
sites. Accordingly to provide additional flexibility in the proposed
RCRA Subtitle D rules, and to address concerns regarding the potential
for disposal capacity shortfalls, EPA is not proposing an outright ban
on siting of existing CCR disposal units in wetlands.
    However, EPA continues to believe that siting new CCR disposal
units in wetlands should only be done under very limited conditions.
The Agency is therefore proposing a comprehensive set of demonstration
requirements. In addition, the Agency believes that when such
facilities are sited in a wetland, that the owner or operator should
offset any impacts through appropriate and practicable compensatory
mitigation actions (e.g., restoration of existing degraded wetlands or
creation of man-made wetlands). This approach is consistent with the
Agency's goal of achieving no overall net loss of the nation's
remaining wetland base, as defined by acreage and function.
Specifically, Sec.  257.61(a)(4) requires owners or operators of new
CCR landfills and surface impoundments to demonstrate that steps have
been taken to achieve no net loss of wetlands (as defined by acreage
and function) by first avoiding impacts to wetlands and then minimizing
such impacts to the maximum extent feasible, and finally, offsetting
any remaining wetland impacts through all appropriate and feasible
compensatory mitigation actions (e.g., restoration of existing degraded
wetlands or creation of man-made wetlands).
    The Agency has also included other requirements to ensure that the
demonstrations required under the proposed rule are comprehensive and
ensure no reasonable probability of adverse effects to human health and
the environment. First, EPA has included language in Sec.  257.61(a)(2)
clarifying that the owner or operator must demonstrate that both the
construction and operation of the unit will not result in violations of
the standards specified in Sec.  257.61(a)(2)(i)-(iv). Second, in Sec.
257.61(a)(3) EPA proposes to identify the factors the owner or operator
must address in demonstrating that the unit will not cause or
contribute to significant degradation of wetlands. These factors, which
were partially derived from the section 404(b)(1) guidelines, address
the integrity of the CCR unit and its ability to protect the ecological
resources of the wetland. In addition, EPA is proposing requirements
for third-party certification and state/public notice, to provide some
verification of facility practices, and to generally assist citizens'
ability to effectively intervene and enforce the requirements, as
necessary.
    Fault Areas. The proposed rule would ban the location of new CCR
landfills and any surface impoundment within 200 feet (60 meters) of
faults that have experienced displacement during the Holocene Epoch.
The Holocene is a unit of geologic time, extending from the end of the
Pleistocene Epoch to the present and includes the past 11,000 years of
the Earth's history. EPA is proposing to define a fault to include a
zone or zones of rock fracturing in any geologic material along which
there has been an observable amount of displacement of the sides
relative to each other. Faulting does not always occur along a single
plane of movement (a ``fault''), but rather along a zone of movement (a
``fault zone''). Therefore, ``zone of fracturing,'' which means a fault
zone in the context of the definition, is included as part of the
definition of fault, and thus the 200-foot setback distance will apply
to the outermost boundary of a fault or fault zone.
    The 200-foot setback was first adopted by EPA in the criteria for
municipal solid waste landfills (MSWLFs), codified at 40 CFR part 258.
In the course of that proceeding, EPA documented that seismologists
generally believed that the structural integrity of MSWLFs could not be
unconditionally guaranteed when they are built within 200-feet of a
fault along which movement is highly likely to occur. Moreover, EPA
relied on a study that showed that damage to engineered structures from
earthquakes is most severe when the structures were located within 200-
feet of the fault along which displacement occurred. Because the
engineered structures found at MSWLFs are similar to those found in CCR
disposal units, EPA expects that the potential for damage to those
structures would be similar in the event of an earthquake near a CCR
landfill or surface impoundment. Therefore, EPA is proposing a similar
setback requirement for new CCR landfills and all surface impoundments.
In general, EPA believes that the 200-foot buffer zone is necessary to
protect engineered structures from seismic damages. EPA also expects
that the 200-foot buffer is appropriate for CCR surface impoundments,
but seeks comment and data on whether the buffer zone should be greater
for such units.
    However, the Agency is also concerned that the 200-foot setback may
be overly protective in some geologic formations, but it is unable to
provide a clear definition of these geologic formations. Therefore, the
Agency is proposing to allow the opportunity for an owner or operator
of a new CCR disposal unit to demonstrate that an alternative setback
distance of less than 200 feet will prevent damage to the structural
integrity of facility and will be protective of human health and the
environment. The demonstration must be certified by an independent
registered professional engineer and the owner or operator of the CCR
disposal unit must notify the state that the demonstration has been
placed in the operating record and on the company's internet site. This
approach is consistent with other sections of today's RCRA subtitle D
co-proposal for alternatives to the specified self-implementing
requirement.
    Seismic Impact Zones. As noted, the proposed rule would also ban
the location of new CCR landfills and any surface impoundments in
seismic impact zones, unless owners or operators demonstrate that the
unit is designed to resist the maximum horizontal acceleration in
lithified earth material for the site. The design features

to be protected include all containment structures (i.e., liners,
leachate collection systems, and surface water control systems). The
demonstration must be certified by an independent registered
professional engineer and the owner or operator must notify the state
that the demonstration has been placed in the operating record and on
the company's internet site. For purposes of this requirement, EPA is
proposing to define seismic impact zones as areas having a 10 percent
or greater probability that the maximum expected horizontal
acceleration in hard rock, expressed as a percentage of the earth's
gravitation pull (g), will exceed 0.10g in 250 years. This is based on
the existing part 258.14 definition of seismic impact. The maps for the
250-year intervals are readily available for all of the U.S. in the
U.S. Geological Survey Open-File Report 82-1033, entitled
``Probabilistic Estimates of Maximum Acceleration and Velocity in Rock
in the Contiguous United States.''
    Another approach would be to adopt criteria of the National
Earthquake Hazards Reduction Program (NEHRP) of the U.S. Geological
Survey used to develop national seismic hazard maps. The NEHRP uses
ground motion probabilities of 2, 5, and 10% in 50 years to provide a
relative range of seismic hazard across the country. The larger
probabilities indicate the level of ground motion likely to cause
problems in the western U.S. The smaller probabilities show how
unlikely damaging ground motions are in many places of the eastern U.S.
The maps are available at http://earthquake.usgs.gov/hazards/products/.
A 50 year time period is commonly used because it represents the
typical lifespan of a building, and a 2% probability level is generally
considered an acceptable hazard level for building codes. For areas
along known active faults, deterministic and scenario ground motion
maps could be used to describe the expected ground motions and effects
of specific hypothetical large earthquakes (see http://
earthquake.usgs.gov/hazards/products/scenario/). The Agency solicits
comments on the proposed definition and whether there are variants like
those used to develop the national seismic hazard maps that could
lessen the burden on the industry and the geographic areas covered by
the proposed definition. For additional information on the National
Seismic Hazard Mapping Project, see http://earthquake.usgs.gov/hazards/
about/.
    Unstable Areas. EPA is proposing to require owners or operators of
all CCR landfills, surface impoundments and lateral expansions located
in unstable areas to demonstrate that the integrity of the structural
components of the unit will not be disrupted. EPA's damage cases have
provided indirect evidence of the kind of environmental and human
health risks that would be associated with failure of the structural
components of the surface impoundment from subsidence or other
instability of the earth at a CCR disposal unit. Accordingly, EPA
believes that, to provide a reasonable probability of preventing
releases and consequent damage to health and the environment from CCRs
released from landfills or surface impoundments, limits on the siting
of such disposal units is appropriate.
    The proposed Subtitle D rule provides that ``unstable areas'' are
locations that are susceptible to natural or human-induced events or
forces capable of impairing the integrity of some or all of the CCR
disposal unit's structural components responsible for preventing
releases from such units. Unstable areas are characterized by localized
or regional ground subsidence, settling (either slowly, or very rapidly
and catastrophically) of overburden, or by slope failure. The owner or
operator must consider the following factors when determining whether
an area is unstable: (1) On-site or local soil conditions that may
result in significant differential settling; (2) on-site or local
geologic or geomorphologic features; and (3) on-site or local human-
made features or events (on both the surface and subsurface). The
structural components include liners, leachate collection systems,
final cover systems, run-on and run-off control systems, and any other
component used in the construction and operation of the CCR landfill,
surface impoundment or lateral expansion that is necessary for
protection of human health and the environment.
    Unstable areas generally include:
    (1) Poor foundation conditions--areas where features exist that may
result in inadequate foundation support for the structural components
of the CCR landfill, surface impoundment or lateral expansion (this
includes weak and unstable soils);
    (2) Areas susceptible to mass movement--areas where the downslope
movement of soil and rock (either alone or mixed with water) occurs
under the influence of gravity; and
    (3) Karst terraces--areas that are underlain by soluble bedrock,
generally limestone or dolomite, and may contain extensive subterranean
drainage systems and relatively large subsurface voids whose presence
can lead to the rapid development of sinkholes.
    Karst areas are characterized by the presence of certain
physiographic features such as sinkholes, sinkhole plains, blind
valleys, solution valleys, losing streams, caves, and big springs,
although not all these features are always present. EPA's intent in
this proposed requirement is to include as an unstable area only those
karst terraces in which rapid subsidence and sinkhole development have
been a common occurrence in recent geologic time. Many of the karst
areas are shown on the U.S. Geological Survey's National Atlas map
entitled ``Engineering Aspects of Karst,'' published in 1984.
    Specific examples of such natural or human-induced phenomena
include: Debris flows resulting from heavy rainfall in a small
watershed; the rapid formation of a sinkhole as a result of excessive
local or regional ground-water withdrawal; rockfalls along a cliff face
caused by vibrations set up by the detonation of explosives, sonic
booms, or other mechanisms; or the sudden liquefaction of a soil with
the attendant loss of shear strength following an extended period of
constant wetting and drying. Various naturally-occurring conditions can
make an area unstable and these can be very unpredictable and
destructive, especially if amplified by human-induced changes to the
environment. Such conditions can include the presence of weak soils,
over steepened slopes, large subsurface voids, or simply the presence
of large quantities of unconsolidated material near a watercourse.
    The Agency recognizes that rapid sinkhole formation that occurs in
some karst terraces can pose a serious threat to human health and the
environment by damaging the structural integrity of dams, liners, caps,
run-on/run-off control systems, and other engineered structures.
However, EPA is not proposing an outright ban of CCR landfills and
surface impoundments in all karst terraces because of concerns
regarding the impacts of such a ban in certain regions of the country.
For example, several States (i.e., Kentucky, Tennessee) are comprised
mostly of karst terraces and banning all CCR disposal facilities in
karst terraces would cause severe statewide disruptions in capacity
available for CCR disposal. Moreover, the Agency believes that some
karst terraces may provide sufficient structural support for CCR
disposal units and has accordingly tried to provide flexibility for
siting in these areas. Therefore, EPA is proposing to allow the
construction of new CCR units, and the continued operation of

existing CCR landfills and surface impoundments in karst terraces where
the owner or operator can demonstrate that engineering measures have
been incorporated into the landfill, surface impoundment, or lateral
expansion design to ensure that the integrity of the structural
components of the landfill or surface impoundment will not be
disrupted. The demonstration must be certified by an independent
registered professional engineer, and the owner or operator must notify
the state that the demonstration has been placed in the operating
record and on the company's internet site.
    Closure of Existing CCR Landfills and Surface Impoundments. The
proposed rule would require owners and operators of existing CCR
landfills and surface impoundments that cannot make the demonstrations
required under Sec.  257.62(a) after the effective date of the rule, to
close the landfill or surface impoundment within five years of the date
of publication of the final rule. Closure and post-closure care must be
done in accordance with Sec.  257.100 and Sec.  257.101. The proposed
rule would also allow for a case-by-case extension for up to two more
years if the facility can demonstrate that there is no alternative
disposal capacity and there is no immediate threat to health or the
environment. This demonstration must be certified by an independent
registered professional engineer or hydrologist. The owner or operator
must place the demonstration in the operating record and on the
company's internet site and notify the state that this action was
taken.
    Thus, the proposed rule allows a maximum of 7 years from the
effective date of the final rule if this alternative is finally
promulgated for existing CCR landfills to comply with the unstable area
restrictions, and existing CCR surface impoundments to comply with the
location restrictions or to close. As discussed under the subtitle C
option, EPA believes that five years will, in most cases, be adequate
time to complete proper and effective facility closure and to arrange
for alternative waste management. However, there may be cases where
alternative waste management capacity may not be readily available or
where the siting and construction of a new facility may take longer
than five years. EPA believes the two-year extension should provide
sufficient time to address these potential problems. EPA continues to
believe that impacts on human health and the environment need to be
carefully considered, and therefore, today's proposed rule requires the
owner or operator to demonstrate that there is no available alternative
disposal capacity and there is no potential threat to human health and
the environment before adopting the two-year extension. These time
frames are consistent with those EPA is proposing under its subtitle C
co-proposal for surface impoundments. EPA is aware of no reason that
the time frames would need to differ under subtitle D, but solicits
comment on this issue.
5. Design Requirements
    The CCR damage cases and EPA's quantitative groundwater risk
assessment clearly show the need for effective liners--namely composite
liners--to very significantly reduce the probability of adverse
effects. The co-proposed subtitle D design standards would require that
new landfills and all surface impoundments that have not completed
closure prior to the effective date of the rule, can only continue to
operate if composite liners and leachate collection and removal systems
have been installed. Units must be retrofitted or closed within five
years of the effective date of the final rule, which is the time frame
EPA is proposing for surface impoundments to retrofit or close under
the subtitle C alternative. EPA is proposing to require the same liner
and leachate collection and removal systems as part of the subtitle D
criteria that are being proposed under the RCRA subtitle C co-proposal.
The technical justification for these requirements is equally
applicable to the wastes and the units, irrespective of the statutory
authority under which the requirement is proposed.
    EPA is also proposing to adopt the same approach to new and
existing units under RCRA subtitle D that it is proposing under RCRA
subtitle C. EPA would only require new landfills (or new portions of
existing landfills) to meet these minimum technology requirements for
liners and leachate collection and removal systems. Existing landfills
that continue to receive CCRs after the effective date of the final
rule, would not be required to be retrofitted with a new minimum-
technology liner/leachate collection and removal system (or to close).
They can continue to receive CCRs, and continue to operate as compliant
landfills, without violating the open dumping prohibition. However,
existing landfills would have to meet groundwater monitoring,
corrective action, and other requirements (except as noted) of the
subtitle D criteria, to assure that any groundwater releases from the
unit were identified and promptly remediated. EPA sees no reason or
special argument to adopt any different approach under the co-proposed
subtitle D regulations for CCR landfills, particularly given the volume
of the material and the disruption that would be involved if these
design requirements were applied to existing landfills.
    By contrast, existing surface impoundments that have not completed
closure by the effective date of the final rule would be required to
retrofit to install a liner. This is consistent with, but not identical
to, the approach proposed under the RCRA subtitle C alternative. Under
the subtitle C alternative, EPA is not proposing to require existing
surface impoundments to install the proposed liner systems because the
impoundments would only continue to operate for a limited period of
time. EPA's proposed treatment standards--dewatering the wastes--will
effectively phase out wet handling of CCRs. During this interim period
(seven years as proposed), EPA believes that it would be infeasible to
require surface impoundments to retrofit, and that compliance with the
groundwater monitoring and other subtitle C requirements would be
sufficiently protective. EPA lacks the authority under RCRA subtitle D
to establish a comparable requirement; EPA only has the authority under
RCRA section 4004 to establish standards relating to ``disposal,'' not
treatment, of solid wastes. Although EPA expects that many surface
impoundments will choose to close rather than install a liner, wet-
handling of CCRs can continue, even in existing units, and EPA's risk
assessment confirms that the long-term operation of such units would
not be protective without the installation of the composite liner and
leachate collection system described below.
    The composite liner would consist of two components: An upper
component consisting of a minimum 30-mil flexible membrane liner (FML),
and a lower component consisting of at least a two-foot layer of
compacted soil with a hydraulic conductivity of no more than
1x10-7cm/sec. The FML component would be required to be
installed in direct and uniform contact with the compacted soil
component. (In other words, the new landfill or new surface impoundment
would be required to have a liner and leachate collection and removal
system meeting the same design standard now included in EPA's municipal
solid waste landfill criteria.) EPA solicits comment, however, on
whether any subtitle D option should allow facilities to use an
alternative design for new disposal units, so long as the owner or
operator of a unit could obtain certification from an independent

registered professional engineer or hydrologist that the alternative
design would ensure that the appropriate concentration values for a set
of constituents typical of CCRs will not be exceeded in the uppermost
aquifer at the relevant point of compliance--i.e., 150 meters from the
unit boundary down gradient from the unit, or the property boundary if
the point of compliance (i.e., the monitoring well) is beyond the
property boundary. Although the existing part 258 requirements allow
for such a demonstration, EPA is not proposing such a requirement in
today's rule. EPA's risk assessment shows that only a composite liner
would ensure that disposal of CCR will meet the RCRA section 4004
standard on a national level, even though site specific conditions
could support the use of alternate liner designs in individual
instances. In the absence of a strong state oversight mechanism, such
as a permit, EPA is reluctant to allow facilities to modify this key
protection. Nevertheless, EPA would be interested in receiving data and
information that demonstrates whether under other site conditions, an
alternative liner would be equally protective. In this regard, EPA
would also be interested in information documenting the extent to which
such conditions currently exist at CCR units. If EPA adopts such a
performance standard, EPA anticipates adopting a requirement that is as
consistent as possible with the existing part 258 requirements, and
would require the same documentation and notification procedures as
with the other self-implementing provisions in the co-proposed subtitle
D option.
    --Stability requirements for surface impoundments. In our recent
assessment of surface impoundments managing CCRs, EPA has identified
deficiencies in units currently receiving wet-handled CCRs.\152\ The
damage cases also demonstrate the need for requirements to address the
stability of surface impoundments, to prevent the damages associated
with a catastrophic failure, such as occurred at the TVA facility in
2008. EPA is therefore proposing to adopt as part of the subtitle D
operating criteria for surface impoundments, the same stability
requirements that are proposed as part of the subtitle C alternative.
As explained in that section, these are based on the long-standing MSHA
requirements, with only minor modifications necessary to tailor the
requirements to CCR unit conditions.
---------------------------------------------------------------------------

    \152\ For the findings of the assessment, see: http://
www.epa.gov/epawaste/nonhaz/industrial/special/fossil/surveys/
index.htm#surveyresults.
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    For those surface impoundments which continue to operate, (i.e.,
both new and existing) the proposed regulation would require that an
independent registered professional engineer certify that the design of
the impoundment is in accordance with recognized and generally accepted
good engineering practices for the maximum volume of CCR slurry and
wastewater that will be impounded therein, and that together design and
management features ensure dam stability. The proposed regulation also
requires the facility to conduct weekly inspections to ensure that any
potentially hazardous condition or structural weakness will be quickly
identified. As with the co-proposed RCRA subtitle C option, the
proposed RCRA subtitle D regulation also requires that existing and new
CCR surface impoundments be inspected annually by an independent
registered professional engineer to assure that the design, operation,
and maintenance of the surface impoundment is in accordance with
current, prudent engineering practices for the maximum volume of CCR
slurry and CCR waste water which can be impounded. EPA has concluded,
subject to consideration of public comment, that these requirements are
necessary to ensure that major releases do not occur that would cause
adverse effects on health or the environment.
6. Operating Requirements
    EPA is proposing to establish specific criteria to address the day-
to-day operations of the CCR landfill or surface impoundment. The
criteria were developed to prevent the health and environmental impacts
from CCR landfills and surface impoundments identified in EPA's
quantitative risk groundwater risk assessment and the damage cases.
Included among these criteria are controls relating to runon and runoff
from the surface of the facilities, discharges to surface waters, and
pollution caused by windblown dust from landfills, and recordkeeping.
    --Existing criteria for Endangered Species and Surface Water. CCR
landfills and surface impoundments are currently subject to the open
dumping criteria contained in 40 CFR 257, Subpart A. These minimum
criteria include restrictions on impacts to endangered species under
257.3-2, and impacts to surface water under 257.3-3. As facilities
should already be complying with these requirements, EPA is not
proposing to modify these existing requirements in today's co-proposal.
EPA notes that the surface water criterion is not enforceable by RCRA
citizen suit. The extent to which this criterion may be enforced is
governed by the remedies available under the CWA, which is the source
of the requirement, rather than RCRA. See, e.g., Arc Ecology v. U.S.
Maritime Admin., No. 02:07-cv-2320 (E.D. Cal. Jan. 21, 2010);
Guidelines for the Development and Implementation of State Solid Waste
Management Plans and Criteria for Classification of Solid Waste
Disposal Facilities and Practices, 46 Fed. Reg. 47048, 47050 (Sept. 23,
1981).
    --Run-on and run-off controls. The purpose of the run-on standard
is to minimize the amount of surface water entering the landfill and
surface impoundment facility. Run-on controls prevent (1) Erosion,
which may damage the physical structure of the landfill; (2) the
surface discharge of wastes in solution or suspension; and (3) the
downward percolation of run-on through wastes, creating leachate. The
proposed regulation requires run-on control systems to prevent flow
onto the active portion of the CCR landfill or surface impoundment
during the peak discharge from a 24-hour, 25-year storm. This helps to
ensure that run-off does not cause an overflow of the surface
impoundment or scouring of material from a landfill or the materials
used to build the surface impoundment.
    Run-off is one of the major sources of hazardous constituent
releases from mismanaged waste disposal facilities, including CCR
landfills and surface impoundments. Additionally, run-off control
systems from the active portion of CCR disposal units are required to
collect and control at least the water volume resulting from a 24-hour,
25-year storm. This protects surface water that would otherwise flow
untreated into a body of water. The facility is required to prepare a
report, available to the public, documenting how relevant calculations
were made, and how the control systems meet the standard. A registered
professional engineer must certify that the design of the control
systems meet the standard. Also, the owner or operator is required to
prepare a report, certified by an independent registered professional
engineer, and documenting how relevant calculations were made, and how
the control systems meet the standard. The state must be notified that
the report was placed in the operating record for the site, and the
owner or operator must make it available to the public on the owner's
or operator's internet site. Under the existing part 257 requirements,
to which CCR units are currently subject, runoff must not cause

a discharge of pollutants into waters of the United States that is in
violation of the National Pollutant Discharge Elimination System
(NPDES) under section 402 of the Clean Water Act. (40 CFR 257.3-3). EPA
is not proposing to revise the existing requirement, but is merely
incorporating it here for ease of the regulated community.
    The Agency chose the 24-hour period because it is an average that
includes storms of high intensity with short duration and storms of low
intensity with long duration. EPA believes that this is a widely used
standard, and is also the current standard used for hazardous waste
landfills and municipal solid waste landfill units under 40 CFR Part
258. EPA has no information that warrants a more restrictive standard
for CCR landfills and surface impoundments than for MSWLFs and
hazardous waste landfills.
    Fugitive dust requirements. EPA has included under the co-proposed
RCRA subtitle D regulation requirements similar to those included under
the Subtitle C co-proposal, based upon its risk assessment findings
that fugitive dust control at 35 [micro]g/m3 or less is protective of
human health or the environment. This is discussed in section VI above.
Due to the lack of a permitting oversight mechanism under the RCRA
Subtitle D alternative, and to facilitate citizen-suit enforcement of
the criteria, EPA has provided for certification by an independent
registered professional engineer, notification to the state that the
documentation has been placed in the operating record, and provisions
making available to the public on the owner's or operator's internet
site documentation of the measures taken to comply with the fugitive
dust requirements.
    Recordkeeping requirements. EPA believes that it is appropriate for
interested states and citizens to be able to access all of the
information required by the proposed rule in one place. Therefore, the
co-proposed Subtitle D alternative requires the owner or operator of a
CCR landfill or surface impoundment to record and retain near the
facility in an operating record which contains all records, reports,
studies or other documentation required to demonstrate compliance with
Sec. Sec.  257.60 through 257.83 (relating to the location
restrictions, design criteria, and operating criteria) and 257.90
through 257.101 (relating to ground water monitoring and corrective
action, and closure and post-closure care).
    The proposed rule would also require owners and operators of CCR
surface impoundments that have not been closed in accordance with the
closure criteria to place in the operating record a report containing
several items of information. The reports would be required beginning
every twelfth months after existing CCR surface impoundments would be
required to comply with the design requirements in section 257.71 (that
is, no later than seven years after the effective date of the final
rule) and every twelfth month following the date of the initial plan
for the design, construction, and maintenance of new surface
impoundments and lateral expansions required under Sec.  257.72(b)) to
address:
    (1) Changes in the geometry of the impounding structure for the
reporting period;
    (2) Location and type of installed instruments and the maximum and
minimum recorded readings of each instrument for the reporting period;
    (3) The minimum, maximum, and present depth and elevation of the
impounded water, sediment, or slurry for the reporting period;
    (4) Storage capacity of the impounding structure;
    (5) The volume of the impounded water, sediment, or slurry at the
end of the reporting period;
    (6) Any other change which may have affected the stability or
operation of the impounding structure that has occurred during the
reporting period; and
    (7) A certification by an independent registered professional
engineer that all construction, operation, and maintenance were in
accordance with the plan. The owner or operator would be required to
notify the state that the report has been placed in the operating
record and on the owner's or operator's internet site.
    These reporting requirements are similar to those required under
MSHA regulations for coal slurry impoundments (30 CFR 77.216-4). As the
Agency has stated previously, MSHA has nearly 40 years of experience
writing regulations and inspecting dams associated with coal mining,
which is directly relevant to the issues presented by CCRs in this
proposal. In our review of the MSHA regulations, we found them to be
comprehensive and directly applicable to and appropriate for the dams
used in surface impoundments at coal-fired utilities to manage CCRs.
    The proposed rule would also allow the owner or operator to submit
a certification by an independent registered professional engineer that
there have been no changes to the information in items (1)-(6) above to
the surface impoundment instead of a full report, although a full
report would be required at least every 5 years.
7. Groundwater Monitoring/Corrective Action
    EPA's damage cases and risk assessments all indicate the potential
for CCR landfills and surface impoundments to leach hazardous
constituents into groundwater, impairing drinking water supplies and
causing adverse impacts on human health and the environment. Indeed,
groundwater contamination is one of the key environmental risks EPA has
identified with CCR landfills and surface impoundments. Furthermore, as
mentioned previously, the legislative history of RCRA section 4004
specifically evidences concerns over groundwater contamination from
open dumps. To this end, groundwater monitoring is a key mechanism for
facilities to verify that the existing containment structures, such as
liners and leachate collection and removal systems, are functioning as
intended. Thus, EPA believes that, in order for a CCR landfill or
surface impoundment to show no reasonable probability of adverse
effects on health or the environment, a system of routine groundwater
monitoring to detect any such contamination from a disposal unit, and
corrective action requirements to address identified contamination, is
necessary.
    Today's co-proposed subtitle D criteria require a system of
monitoring wells be installed at new and existing CCR landfills and
surface impoundments. The co-proposed criteria also provide procedures
for sampling these wells and methods for statistical analysis of the
analytical data derived from the well samples to detect the presence of
hazardous constituents released from these facilities. The Agency is
proposing a groundwater monitoring program consisting of detection
monitoring, assessment monitoring, and a corrective action program.
This phased approach to groundwater monitoring and corrective action
programs provide for a graduated response over time to the problem of
groundwater contamination as the evidence of such contamination
increases. This allows for proper consideration of the transport
characteristics of CCR constituents in ground water, while protecting
human health and the environment, and minimizing unnecessary costs.
    In EPA's view, the objectives of a groundwater monitoring and
corrective action regime and analytical techniques for evaluating the
quality of groundwater are similar regardless of the particular wastes
in a disposal unit, and regardless of whether the unit is a

landfill or surface impoundment. Therefore, EPA has largely modeled the
proposed groundwater monitoring and corrective action requirements for
CCR landfills and surface impoundments after those for MSWLFs in the 40
CFR part 258 criteria, and for disposal units that may receive
conditionally-exempt small quantity generator (CESQG) hazardous waste
under 40 CFR part 257, subpart B. EPA believes that the underlying
rationale for those requirements is generally applicable to groundwater
monitoring and corrective action for CCR landfills and surface
impoundments. Accordingly, EPA does not discuss these requirements at
length in today's preamble. Rather, EPA refers the reader to the
detailed discussions of these requirements in the preambles to the
final and proposed rules for the MSWLF criteria for more
information.\153\ See Solid Waste Disposal Facility Criteria, 56 Fed.
Reg. 50978 (Oct. 9, 1991) (final rule); Solid Waste Disposal Facility
Criteria, 53 Fed. Reg. 33314 (Aug. 30, 1988) (proposed rule).
---------------------------------------------------------------------------

    \153\ The preambles to the CESQG rules have more limited
discussions of these requirements. See Criteria for Classification
of Solid Waste Disposal Facilities and Practices; Identification and
Listing of Hazardous Waste; Requirements for Authorization of State
Hazardous Waste Programs, 61 FR 34252, 34259-61 (July 1, 1996)
(final rule); Criteria for Classification of Solid Waste Disposal
Facilities and Practices; Identification and Listing of Hazardous
Waste; Requirements for Authorization of State Hazardous Waste
Programs, 60 FR 30964, 30975-77 (June 12, 1995) (proposed rule).
---------------------------------------------------------------------------

    However, for a number of the requirements, EPA is proposing to
modify or revise these requirements. Below, EPA discusses the
particular areas where the Agency is proposing to make modifications,
and solicits comment on those specific differences. EPA, more
generally, solicits comment on whether relying on the existing
groundwater monitoring and corrective action requirements for MSWLFs
and CESQG facilities, as modified in today's proposal, are appropriate
for CCR landfills and surface impoundments.
    Relying on the existing criteria in 40 CFR 258 and 257 Subpart B
has several advantages. Specifically, like the co-proposed Subtitle D
regulations for CCR disposal, these requirements are structured to be
largely self-implementing. In addition, states and citizens should
already be familiar with those processes, which have been in place
since 1991, and EPA expects that this familiarity with the processes
may facilitate the states' creation of regulatory programs for CCR
disposal facilities under state law, to the extent they do not already
exist, and thus providing oversight (which EPA believes is important in
implementing these rules) that is already found through MSWLFs and
CESQG landfill permitting programs. Furthermore, familiarity with the
overall approach may facilitate the states' and citizens' oversight of
CCR disposal activities through the citizen suit mechanism, which is
available, regardless of whether a state has adopted a regulatory
program under state law for CCR disposal facilities.
    At the same time, however, EPA is mindful of the differences in the
statutory authorities for establishing criteria for CCR landfills and
surface impoundments versus MSWLFs and CESQG facilities, and in
particular, the possibility that a state may lack a permit program for
CCR disposal units. Accordingly, EPA has sought to tailor these
proposed requirements in the CCR disposal context, in particular by
including in several of the proposed requirements a certification by an
independent registered professional engineer or, in some cases,
hydrologist, in lieu of the state approval mechanisms that are used in
the 40 CFR part 258/257, Subpart B criteria. Such certifications are
found in proposed Sec. Sec.  257.95(h) (establishment of an alternative
groundwater protection standard for constituents for which MCLs have
not been established); and 257.97(e) (determination that remediation of
a release of an Appendix IV constituent from a CCR landfill or surface
impoundment is not necessary). As discussed earlier in this preamble,
EPA believes that this provides an important independent validation of
the particular route chosen. EPA solicits comment in particular on the
appropriateness of relying on such a mechanism under the proposed
groundwater monitoring and corrective action criteria.
    In other instances, however, EPA has decided not to propose to
allow facilities to operate under an alternative standard, such as the
existing provisions under 257.21(g) and 258.50(h) (establishing
alternative schedules for groundwater monitoring and corrective
action); and 258.54(a)(1) and (2), and 257.24(a)(1) and (2), which
allow the Director of an approved State to delete monitoring
parameters, and establish an alternative list of indicator parameters,
under specified circumstances. EPA is proposing not to adopt these
alternatives for CCR disposal facilities because groundwater monitoring
is the single most critical set of protective measures on which EPA is
relying to protect human health and the environment. EPA is not
proposing to require existing landfills to retrofit to install a
composite liner. Since these units will continue to operate in the
absence of a composite liner, groundwater monitoring is the primary
means to prevent groundwater contamination. Although EPA is proposing
to require existing surface impoundments to retrofit with composite
liners, these units are more susceptible to leaking, and thus the need
for a rigorous groundwater monitoring program is correspondingly high.
Moreover, EPA is concerned that provisions allowing such modification
of these requirements are particularly susceptible to abuse, since such
provisions would allow substantial cost avoidance. Therefore, in the
absence of a state oversight mechanism in place to ensure such
modifications are technically appropriate, such a provision may operate
at the expense of protectiveness. In addition, given the extremely
technical nature of these requirements, EPA is concerned that such
provisions would render the requirements appreciably more difficult for
citizens to effectively enforce. In some instances, including these
alternative standards would not be workable. For example, establishing
alternative schedules under the groundwater monitoring and corrective
action provisions (as currently provided under 257.21(g) and 258.50(h))
the Agency believes would not be workable in the context of a self-
implementing rule, because there is no regulatory entity to judge the
reasonableness of the desired alternatives. The Agency thus solicits
comments on these omissions from today's proposed rule, and also on
whether a more prescriptive approach could or should be developed under
subtitle D of RCRA. EPA also solicits comment on whether the
requirement for certification by an independent professional engineer
would be effective or appropriate in such a case.
    Applicability. The co-proposed subtitle D criteria require
facilities to install a groundwater monitoring system at existing
landfills and surface impoundments within one year of the effective
date of the regulation so that any releases from these units will be
detected, thus providing an opportunity to detect and, if necessary,
take corrective action to address any releases from the facilities. The
proposed rule also provides that new CCR landfills and surface
impoundments comply with the groundwater monitoring requirements in the
rule before CCRs can be placed in the units. EPA expects that the one-
year timeframe for existing units is a reasonable time for facilities
to install the necessary systems. This is the same time frame provided
to

facilities under the existing part 265 interim status regulations, and
past experience demonstrates this implementation schedule would
generally be feasible. Although one year for the installation of
groundwater monitoring is a shorter time frame than EPA provided to
facilities as part of the original part 258 or part 257 subpart A
requirements, there are good reasons to establish a shorter time frame
here. As discussed in section IV, many of the existing units into which
much of the CCR is currently disposed are unlined, and they are aging.
Under these circumstances, EPA believes that installation of
groundwater monitoring is critical to ensure that releases from these
units are detected and addressed appropriately. Moreover, EPA offered a
longer implementation period in 1991 based on a factual finding that a
shortage of drilling contractors existed; in the 1995 rule establishing
groundwater monitoring requirements for CESQG facilities, EPA
determined that this shortage had ended. EPA is aware of no information
to suggest that a similar shortage exists today, but specifically
solicits comment on this issue.
    EPA has not included provisions for suspension of ground water
monitoring that is currently allowed under 257.21(b) and 258.50(b).
This is one of those provisions discussed above, that EPA believes are
potentially, particularly susceptible to abuse, and EPA is reluctant to
adopt a comparable provision in the absence of an approved state permit
program. In addition, since these proposed criteria are designed to be
applied even in the absence of state action, EPA has not included
provisions for state establishment of a compliance schedule under
257.21(d) and 258.50(d). EPA solicits comment on whether these types of
provisions are appropriate for CCR landfills and surface impoundments.
    Section 257.90 also requires that the owner or operator of the CCR
landfill or surface impoundment must notify the state once each year
throughout the active life and post-closure care period that such
landfill or surface impoundment is in compliance with the groundwater
monitoring and corrective action provisions of this subpart. This
notification must also be placed on the owner or operator's internet
site. EPA believes that annual notification will facilitate state
oversight of the groundwater monitoring and corrective action
provisions.
    Groundwater monitoring systems. The co-proposed subtitle D criteria
require facilities to install, at a minimum, one up gradient and three
down gradient wells at all CCR units. EPA is proposing this requirement
based on the subtitle C interim status self-implementing requirements.
    The design of an appropriate groundwater monitoring system is
particularly dependent on site conditions relating to groundwater flow,
and the development of a system must have a sufficient number of wells,
installed at appropriate locations and depths, to yield groundwater
samples from the uppermost aquifer that represents the quality of
background groundwater that has not been affected by contaminants from
CCR landfills or surface impoundments. EPA's existing requirements
under parts 257, Subpart B, 258, and 264 all recognize this, and
because they operate in a permitting context, these requirements do not
generally establish inflexible minimum requirements. Because the same
guarantee of permit oversight is not available under the criteria
developed for this proposal, EPA believes that establishing a minimum
requirement is necessary. Past experience demonstrates that these
monitoring requirements will be protective of a wide variety of
conditions and wastes, and that facilities can feasibly implement these
requirements. Moreover, in many instances a more detailed groundwater
monitoring system may need to be in place, and EPA is therefore
requiring a certification by the independent registered professional
engineer or hydrologist that the groundwater monitoring system is
designed to detect all significant groundwater contamination.
    Groundwater sampling and analysis requirements. Owners and
operators need to ensure that consistent sampling and analysis
procedures are in place to determine whether a statistically
significant increase in the level of a hazardous constituent has
occurred, indicating the possibility of groundwater contamination. The
co-proposed subtitle D criteria would require the same provisions
addressing groundwater sampling and analysis procedures with those
already in use for CESQG and MSWLF facilities, since generally the same
constituents and analysis procedures would be appropriate in both
instances. However, EPA is requesting comment on one issue in
particular. In the final MSWLF criteria, EPA noted that in order to
ensure protection of human health and the environment at MSWLFs, it was
important to make sure that the right test methodology from among those
listed in this section was selected for the conditions present at a
particular MSWLF. At the time, EPA indicated its expectation that as
states gained program approval, they would take on the responsibility
of approving alternate statistical tests proposed by the facilities.
See 56 Fed. Reg. 51071. Because states may choose not to create a
regulatory oversight mechanism under the co-proposed subtitle D rule
for CCR landfills and surface impoundments, however, EPA is requesting
comment on whether the lack of such an oversight mechanism will impair
selection of appropriate test methodologies, and whether EPA should
instead adopt a different approach to ensure the protection of human
health and the environment at CCR disposal facilities. For example, one
approach might be for EPA to tailor a list of methodologies to
particular site conditions. EPA would welcome suggestions from
commenters on alternative approaches to this issue.
    Detection monitoring program. The parameters to be used as
indicators of groundwater contamination are the following: boron,
chloride, conductivity, fluoride, pH, sulphate, sulfide, and total
dissolved solids (TDS). In selecting the parameters for detection
monitoring, EPA selected constituents that are present in CCRs, and
would rapidly move through the subsurface and thus provide an early
detection as to whether contaminants were migrating from the disposal
unit. EPA specifically solicits comment on the appropriateness of this
list of parameters.
    In this provision of the proposed RCRA subtitle D co-proposed rule,
EPA has decided not to include provisions parallel to 258.54(a)(1) and
(2), and 257.24(a)(1) and (2) which allow the Director of an approved
State to delete monitoring parameters, and establish an alternative
list of indicator parameters, under specified circumstances. EPA is not
including these provisions because it believes that a set of specified
parameters are necessary to ensure adequate protectiveness, since EPA's
information on CCRs indicates that their composition would not be
expected to vary such that the parameters are inappropriate. Under the
proposed rule, monitoring would be required no less frequently than
semi-annually. EPA has again decided not to include a provision that
would allow an alternative sampling frequency, because of the lack of
guaranteed state oversight and potential for this provision to diminish
protection of human health and the environment, as mentioned in the
introductory discussions above. EPA solicits comments on whether it
should allow deletion of monitoring parameters and alternative sampling
frequencies, based on compliance with a performance standard that has
been

documented by an independent registered professional engineer or
hydrologist. Commenters interested in supporting such an option are
encouraged to provide data to demonstrate the conditions under which
such alternatives would be protective, as well as information to
indicate the prevalence of such conditions at CCR facilities.
    Assessment monitoring program. When a statistically significant
increase over background levels is detected for any of the monitored
constituents, the rule would require the facility to begin an
assessment monitoring program to detect releases of CCR constituents of
concern including aluminum, antimony, arsenic, barium, beryllium,
boron, cadmium, chloride, chromium, copper, fluoride, iron, lead,
manganese, mercury, molybdenum, pH, selenium, sulphate, sulfide,
thallium, and total dissolved solids.
    EPA specifically solicits comment on the appropriateness of this
list of parameters. For the same reasons as discussed under the
proposed requirements for detection monitoring, EPA has chosen not to
include in the proposed requirements for assessment monitoring
provisions for allowing a subset of wells to be sampled, the deletion
of assessment monitoring parameters, or alternative sampling
frequencies. EPA again solicits comment on whether these options are
appropriate for CCR landfills and surface impoundments.
    Assessment of corrective measures. The proposed rule also requires
that whenever monitoring results indicate a statistically significant
level of any appendix IV constituent exceeding the groundwater
protection standard, the owner or operator must initiate an assessment
of corrective action remedies. Unlike for the MSWLF and CESQG criteria,
the proposed rule provides a discrete time frame for completion of the
assessment, at 90 days, while the earlier criteria provided for its
completion within a ``reasonable period of time.'' EPA believes that
without a state oversight mechanism, a finite time frame is
appropriate. EPA selected 90 days as the period over which the
assessment must be completed because it expects that this will be a
sufficient length of time to complete the required activities. EPA
solicits comment on the appropriateness of the 90-day timeframe.
    Selection of Remedy. The proposed rule establishes a framework for
remedy selection based upon the existing requirements for MSWLFs and
CESQG facilities. These provisions have been modified to eliminate
consideration of ``practicable capabilities'' where such considerations
have been included in the MSWLF and CESQG criteria. EPA believes that
it does not have the discretion to include this consideration under the
RCRA subtitle D co-proposal, because this consideration is explicitly
required under the terms of RCRA section 4010. That section by its
terms applies to facilities that may receive household hazardous wastes
and CESQG wastes, and so is inapplicable to today's co-proposed
standards for CCR landfills and surface impoundments. See 42 U.S.C.
6949a(c)(1). EPA solicits comment on these modifications, specifically,
on how this modification may affect the ability of the regulated
community to comply with the proposed criteria, and on how this
modification may affect the protectiveness of the proposed standards
for human health and the environment.
    In the provisions discussing factors to be considered in
determining whether interim measures are necessary, EPA has modified
proposed 257.98(a)(3)(vi), to eliminate consideration of risks of fire
or explosion, since EPA does not expect that these risks would be
relevant to the disposal of CCRs in CCR landfills and surface
impoundments.
    Implementation of the corrective action remedy. The co-proposed
subtitle D criteria require that the owner or operator comply with
several requirements to implement the corrective action program, again
modeled after the existing requirements for MSWLFs and CESQG
facilities. Similar to proposed section 257.97, these provisions have
been made consistent with the underlying statutory authorities for this
proposed rule. See discussions above.
    In these provisions, EPA has decided not to include a provision
that is included in the MSWLF criteria in 258.58(e)(2) and
257.28(e)(2), allowing an alternative length of time during which the
owner or operator must demonstrate that concentrations of constituents
have not exceeded the ground water protection standards, in support of
a determination that the remedy is complete. See proposed 257.98(e)(2).
Instead, the proposed rule would require a set period of three
consecutive years. EPA solicits comment on whether to allow for a
different period of time. EPA is particularly concerned with whether
such a provision would provide protection to human health or the
environment because of the lack of a guaranteed state oversight
mechanism.
8. Closure and Post-Closure Care
    Effective closure and post-closure care requirements, such as
requirements to drain the surface impoundment, are essential to
ensuring the long-term safety of disposal units. Closure requirements,
such as placing the cover system on the disposal unit, ensure that
rainfall is diverted from the landfill or surface impoundment,
minimizing any leaching that might occur based on the hydraulic head
placed on the material in the unit. EPA's Guide for Industrial Waste
Management, prepared in consultation with industry experts, a Tribal
representative, state officials, and environmental groups, documents
the general consensus on the need for effective closure and post-
closure requirements.\154\ Post-closure care requirements are also
particularly important for CCR units because the time to peak
concentrations for selenium and arsenic, two of the more problematic
constituents contained in CCR wastes, is particularly long, and
therefore the peak concentrations in groundwater may not occur during
the active life of the unit. Continued groundwater monitoring is
therefore necessary during the post-closure care period to ensure the
continued integrity of the unit and the safety of human health and the
receiving environment. For these provisions, then, EPA has again
modeled its proposed requirements for CCR landfills on those already in
place for MSWLFs with modifications to reflect the lack of a mandatory
permitting mechanism, and other changes that it believes are
appropriate to ensure that there is no reasonable probability of
adverse effects from the wastes that remain after a unit has closed.
For surface impoundments, EPA has modeled its proposed requirements on
the part 265 interim status closure requirements for surface
impoundments, as well as the MSHA requirements. EPA solicits comment on
whether these proposed requirements are appropriate for CCR landfills
and surface impoundments.
---------------------------------------------------------------------------

    \154\ Guide for Industrial Waste Management, available at http:/
/www.epa.gov/epawaste/nonhaz/industrial/guide/index.htm.
---------------------------------------------------------------------------

    Requirements specific to closure of CCR landfills and surface
impoundments include proposed 257.100(a)-(c). These provisions provide
that prior to closure of any CCR unit, the owner or operator must
develop a plan describing the closure of the unit, and a schedule for
implementation. The plan must describe the steps necessary to close the
CCR landfill or surface impoundment at any point during the active life
in

accordance with the requirements in paragraphs (c) and (d) or (e) of
this section, as applicable, and based on recognized and generally
accepted good engineering practices. EPA is proposing to define
recognized and generally accepted good engineering practices in the
same manner as it is proposing under the subtitle C alternative. The
definition references but does not attempt to codify any particular set
of engineering practices, but to allow the professional engineer
latitude in adopting improved practices that reflect the state-of-the
art practices, as they develop over time. The plan must be certified by
an independent registered professional engineer. In addition, the owner
or operator must notify the state that a plan has been placed in the
operating record and on the owner's or operator's publically accessible
Internet site.
    These provisions are modeled after the closure plan requirements in
258.60(c). Of note here is that, while EPA rejected a certification
requirement for MSWLF closure plans, EPA is proposing to require one
here to increase the ability of citizens to effectively enforce the
rules. In the MSWLF rule, EPA rejected a certification requirement
because ``it will be relatively easy to verify that the plan meets the
requirements,'' due to the specific design criteria specified in the
rule. However, this was in the context of a state program, where EPA
could assure that states would play an active role in overseeing and
enforcing the facility's implementation of the requirements.
    EPA is also proposing that the closure plan provide, at a minimum,
the information necessary to allow citizens and states to determine
whether the facility's closure plan is reasonable. This includes an
estimate of the largest area of the CCR unit ever requiring a final
cover during the active life of the unit, and an estimate of the
maximum inventory of CCRs ever on-site during the active life of the
unit.
    Proposed 257.100(b) of the rule allows closure of a CCR landfill or
surface impoundment with CCRs in place or through CCR removal and
decontamination of all areas affected by releases from the landfill or
surface impoundment. Proposed paragraph (c) provides that CCR removal
and decontamination are complete when constituent concentrations
throughout the CCR landfill or surface impoundment and any areas
affected by releases from the CCR landfill or surface impoundment do
not exceed the numeric cleanup levels for those CCR constituents, to
the extent that the state has established such clean up levels in which
the CCR landfill or surface impoundment is located. These ``clean-
closure'' provisions are modeled after EPA's ``Guide for Industrial
Waste Management,'' found at http://www.epa.gov/epawaste/nonhaz/
industrial/guide/chap11s.htm. As previously noted, the Guide represents
a consensus view of best practices for industrial waste management,
based on involvement from EPA, and state and tribal representatives, as
well as a focus group of industry and public interest stakeholders
chartered under the Federal Advisory Committee Act. EPA has included
this provision to allow some flexibility in the self-implementing
scheme for facilities in their closure options, while providing
protection for health and the environment under either option. Although
EPA anticipates that facilities will mostly likely not clean close
their units, given the expense and difficulty of such an operation, EPA
believes that they are generally preferable from the standpoint of land
re-use and redevelopment, and so wishes explicitly to allow for such
action in the proposed subtitle D rule. EPA is also considering whether
to adopt a further incentive for clean closure, under which the owner
or operator of the CCR landfill or surface impoundment could remove the
deed notation required under proposed 257.100(m), if all CCRs are
removed from the facility, and notification is provided to the state.
In the absence of state cleanup levels, metals should be removed to
either statistically equivalent background levels, or to maximum
contaminant levels (MCLs), or health-based numbers. One tool that can
be used to help evaluate whether waste removal is appropriate at the
site is the risk-based corrective action process (RBCA) using
recognized and generally accepted good engineering practices such as
the ASTM Ec0-RBCA process. EPA solicits comment on the appropriateness
of this provision under a RCRA subtitle D rule, and information on the
number of facilities that may take advantage of a clean-closure option.
    For closure of surface impoundments with CCRs in place, EPA has
developed substantive requirements modeled on a combination of the
existing 40 CFR part 265 interim status requirements for surface
impoundments, and the long-standing MSHA standards. At closure, the
owner or operator of a surface impoundment would be required to either
drain the unit, or solidify the remaining wastes. EPA is also proposing
to require that the wastes be stabilized to a bearing capacity
sufficient to support the final cover. The proposed criteria further
require that, in addition to the technical cover design requirements
applicable to landfills, any final cover on a surface impoundment would
have to meet requirements designed to address the nature of the large
volumes of remaining wastes. Specifically, EPA is proposing that the
cover be designed to minimize, over the long-term, the migration of
liquids through the closed impoundment; promote drainage; and
accommodate settling and subsidence so that the cover's integrity is
maintained. Finally, closure of the unit is also subject to the general
performance standard that the probability of future impoundment of
water, sediment, or slurry is precluded. This general performance
standard is based on the MSHA regulations, and is designed to ensure
the long-term safety of the surface impoundment.
    The proposed RCRA subtitle D regulation requires that CCR landfills
and surface impoundments have a final cover system designed and
constructed to have a permeability less than or equal to the
permeability of any bottom liner system or natural subsoils present, or
a permeability no greater than 1 x 10-5 cm/sec, whichever is
less; it also requires an infiltration layer that contains a minimum of
18 inches of earthen material. The regulation also requires an erosion
layer that contains a minimum of 6 inches of earthen material that is
capable of sustaining native plant growth as a way to minimize erosion
of the final cover. These requirements are generally modeled after the
performance standard and technical requirements contained in the
existing RCRA subtitle D rules for MSWLFs, in 258.60. EPA is also
proposing, however a fourth requirement not found in those criteria
modeled after the interim status closure requirements of
265.228(a)(iii)(D) that accounts for the conditions found in surface
impoundments. Specifically, EPA is proposing that the final cover be
designed to minimize the disruption of the final cover through a design
that accommodates settling and subsidence. EPA believes that these
requirements strike a reasonable balance between the costs of a
protective final cover, and avoiding risks to health and the
environment from the remaining wastes at the CCR landfill or surface
impoundment. The regulation requires certification by an independent
registered professional engineer that these standards were met. The
design of the final cover system, including the certification, must be
placed in the operating record and on the owner's or

operator's Internet site. Based on the MSHA standards, EPA is also
proposing that unit closure must provide for major slope stability to
prevent the sloughing of the landfill over the long term.
    Alternatively, the rule allows the owner or operator of the CCR
landfill or surface impoundment to select an alternative final cover
design, provided the alternative cover design is certified by an
independent registered professional engineer and notification is
provided to the state that the alternative cover design has been placed
in the operating record and on the owner's or operator's Internet site.
The alternative final cover design must include a infiltration layer
that achieves an equivalent reduction in infiltration, and an erosion
layer that provides equivalent protection from wind and water erosion,
as the infiltration and erosion layers specified in the technical
standards in paragraph (d). Under this alternative, EPA expects that
evapo-transpiration covers may be an effective alternative, which are
not appropriately evaluated based on permeability alone. For example,
an independent registered professional engineer might certify an
alternative cover design that prevents the same level of infiltration
as the system described above (i.e., no greater than 1 x
10-5 cm/sec, etc), based on: (1) hydrologic modeling and
lysimetry or instrumentation using a field scale test section, or (2)
Hydrologic modeling and comparison of the soil and climatic conditions
at the site with the soil and climatic conditions at an analogous site
with substantially similar cover design. In this case, the owner or
operator of the disposal unit must obtain certification from an
independent registered professional engineer that the alternative cover
would minimize infiltration at least as effectively as the ``design''
cover described above. As with the other final covers, the design of
the evapo-transpiration cover must be placed on the owner's or
operator's Internet site.
    EPA has included this alternative cover requirement to increase the
flexibility for the facility to account for site-specific conditions.
However, EPA is specifically soliciting comment on whether this degree
of flexibility is appropriate, given the lack of guaranteed state
oversight. In the final MSWLF rule, EPA adopted a comparable provision,
but concluded that this alternative would not be available in States
without approved programs. See, 56 FR 51096. Given that EPA can neither
approve state programs, nor rely on the existence of a state permit
process, EPA questions whether this kind of requirement is appropriate.
Commenters who believe this requirement would be appropriate are
encouraged to include examples documenting the need for flexibility in
developing cover requirements, as well as data and information to
demonstrate that alternative cover designs would be protective. EPA
would also welcome suggestions for other methods to allow owners and
operators of CCR landfills and surface impoundment facilities to
account for site-specific conditions that provide a lower degree of
individual facility discretion, such as a list of approved cover
designs.
    The proposed rule includes the same 30- and 180-day deadlines for
beginning and completing closure, respectively, that are contained in
existing section 258.60(f) and (g) for MSWLFs. However, EPA has decided
not to propose to include a provision under which the owner and
operator could extend those deadlines under the MSWLF criteria. EPA
believes that extending the closure deadlines in this context is
inappropriate because, in the absence of an approved State program, the
owner or operator could unilaterally decide to extend the time for
closure of the unit, without any basis, or oversight by a regulatory
authority.
    The proposed closure requirements also include a provision
addressing required deed notations. In this regard, EPA is considering
whether to include a provision for removing the deed notation once all
CCRs are removed from the facility, and notification is provided to the
state of this action. In the MSWLF rule, we adopted such a provision,
but determined that state oversight of such a provision was essential,
given the potential for abuse. As we noted in the final MSWLF rule,
``EPA strongly believes that a decision to remove the deed notation
must be considered carefully and that in practice very few owners or
operators will be able to take advantage of the provision.'' EPA
solicits comment on the propriety of such a provision, and encourages
commenters who are interested in supporting such an option, to suggest
alternatives to state oversight to provide for facility accountability.
    Following closure of the CCR management unit, the co-proposed
subtitle D approach requires post-closure care modeled after the
requirements in 258.60. The owner or operator of the disposal unit must
conduct post-closure care for 30 years. EPA is proposing to allow
facilities to conduct post-closure care for a decreased length of time
if the owner or operator demonstrates that (1) the reduced period is
sufficient to protect human health and the environment, as certified by
an independent registered professional engineer; (2) notice is provided
to the state that the demonstration has been placed in the operating
record and on the owner's or operator's Internet site; and (3) the
owner or operator notifies the state of the company's findings. The
proposed rule also allows an increase in this period, again, with
notification to the state, if the owner or operator of the CCR landfill
or surface impoundment determines that it is necessary to protect human
health and the environment. The 30-year period is consistent with the
period required under the criteria for MSWLFs, as well as under the
subtitle C interim status requirements. EPA has no information to
indicate that a different period would be appropriate for post-closure
care for CCR disposal units. EPA recognizes that state oversight can be
critical to ensure that post-closure care is conducted for the length
of time necessary to protect human health and the environment; however,
EPA also recognizes that there is no set length of time for post-
closure care that will be appropriate for all possible sites, and all
possible conditions. EPA therefore solicits comment on alternative
methods to account for different conditions, yet still provide methods
of oversight to assure facility accountability.
    During post-closure care, the owner or operator of the disposal
unit is required to maintain the integrity and effectiveness of any
final cover, maintain and operate the leachate collection and removal
system in accordance with the leachate collection and removal system
requirements described above, maintain the groundwater monitoring
system and monitor the groundwater in accordance with the groundwater
monitoring requirements described above, and place the maintenance plan
in the operating record and on the company's Internet site.
    EPA is also considering whether to adopt a number of provisions to
increase the flexibility available under these requirements. For
example, EPA is considering a self-certified stoppage of leachate
management, such as provided for in 258.61(a)(2), and is soliciting
public comment on the need for such a provision, as well as its
propriety, in light of the absence of guaranteed state oversight. EPA
is also considering whether to adopt a provision to allow any other
disturbance, provided that the owner or operator of the CCR landfill or
surface impoundment demonstrates that disturbance of the final cover,
liner or other component of the containment system, including any
removal of CCRs,

will not increase the potential threat to human health or the
environment. The demonstration would need to be certified by an
independent registered professional engineer, and notification provided
to the state that the demonstration had been placed in the operating
record and on the owner's or operator's Internet site. In the MSWLF
rule, EPA limited this option to approved states, on the ground that,
``under very limited circumstances it may be possible or desirable to
allow certain post-closure uses of land, including some recreational
uses, without posing a significant threat to human health and the
environment, but such situations are likely to be very limited and need
to be considered very carefully.'' Commenters interested in supporting
such an option should address why such a provision would nevertheless
be appropriate in this context. In this regard, EPA would also be
interested in suggestions for other mechanisms providing facility
flexibility and/or oversight.
9. Financial Assurance
    EPA currently requires showings of financial assurance under
multiple programs, including for RCRA subtitle C hazardous waste
treatment, storage and disposal facilities; the RCRA subtitle I
underground storage tank program; and under other statutory
authorities. Financial assurance requirements generally help ensure
that owners and operators adequately plan for future costs, and help
ensure that adequate funds will be available when needed to cover these
costs if the owner or operator is unable or unwilling to do so;
otherwise, additional governmental expenditures may otherwise be
necessary to ensure continued protection of human health and the
environment. Financial assurance requirements also encourage the
development and implementation of sound waste management practices both
during and at the end of active facility operations, since the
associated costs of any financial assurance mechanism should be less
when activities occur in an environmentally protective manner.
    Today's proposed RCRA subtitle D alternative does not include
proposed financial responsibility requirements. Any such requirements
would be proposed separately. Specifically, on January 6, 2010, EPA
issued an advance notice of proposed rulemaking (``ANPRM''),
identifying classes of facilities within the Electric Power Generation,
Transmission, and Distribution industry, among others, as those for
which it plans to develop, as necessary, financial responsibility
requirements under CERCLA Sec.  108(b). See Identification of
Additional Classes of Facilities for Development of Financial
Responsibility Requirements under CERCLA Section 108(b), 75 FR 816
(January 6, 2010). EPA solicits comments on whether financial
responsibility requirements under CERCLA Sec.  108(b) should be a key
Agency focus should it regulate CCR disposal under a RCRA subtitle D
approach. (By today's proposed rule, EPA is not reopening the comment
period on the January 2010 ANPRM, which closed on April 6, 2010. See
Identification of Additional Classes of Facilities for Development of
Financial Responsibility Requirements under CERCLA Section 108(b), 75
FR 5715 (Feb. 4, 2010) (extending comment period to April 6, 2010).)
However, EPA also solicits comment on existing state waste programs for
financial assurance for CCR disposal facilities, and whether and how
the co-proposed RCRA subtitle D regulatory approach might integrate
with those programs.
10. Off-Site Disposal
    Under a subtitle D regulation, regulated CCR wastes shipped off-
site for disposal would have to be sent to facilities that meet the
standards above.
11. Alternative RCRA Subtitle D Approaches
    A potential modification to the subtitle D option that was
evaluated in our Regulatory Impact Analysis (RIA) is what we have
termed a subtitle ``D prime'' option. Under this modification, the
regulations would not require the closure or installation of composite
liners in existing surface impoundments; rather, these surface
impoundments could continue to operate for the remainder of their
useful life. New surface impoundments would be required to have
composite liners. The other co-proposed subtitle D requirements would
remain the same. This modification results in substantially lower
costs, but also lower benefits as described in section XII, which
presents costs and benefits of the RCRA subtitle C, D, and D prime
options. EPA solicits comments on this approach.
    Finally, another approach that has been suggested to EPA is a
subtitle D regulation with the same requirements as spelled out in the
co-proposal, for example, composite liners for new landfills and
surface impoundments, groundwater monitoring, corrective action,
closure, and post-closure care requirements as co-proposed in this
notice; however, in lieu of the phase-out of surface impoundments, EPA
would establish and fund a program for conducting annual (or other
frequency) structural stability (assessments) of impoundments having a
``High'' or ``Significant'' hazard potential rating as defined by
criteria developed by the U.S. Army Corps of Engineers for the National
Inventory of Dams. EPA would conduct these assessments and, using
appropriate enforcement authorities already available under RCRA,
CERCLA, and/or the Clean Water Act, would require facilities to respond
to issues identified with their surface impoundments. The theory behind
this suggested approach is that annual inspections would be far more
cost effective than the phase-out of surface impoundments--
approximately $3.4 million annually for assessments versus $876 million
annually for phase-out. EPA also solicits comments on this approach and
its effectiveness in ensuring the structural integrity of CCR surface
impoundments.

X. How would the proposed subtitle D regulations be implemented?

A. Effective Dates

    The effective date of the proposed RCRA subtitle D alternative, if
this alternative is ultimately promulgated, would be 180 days after
promulgation of a final rule. Thus, except as noted below, owners and
operators of CCR landfills and surface impoundments would need to meet