[Federal Register Volume 80, Number 74 (Friday, April 17, 2015)]
[Rules and Regulations]
[Pages 21301-21501]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-00257]



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Vol. 80

Friday,

No. 74

April 17, 2015

Part II





Environmental Protection Agency





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40 CFR Parts 257 and 261





Hazardous and Solid Waste Management System; Disposal of Coal 
Combustion Residuals From Electric Utilities; Final Rule

Federal Register / Vol. 80 , No. 74 / Friday, April 17, 2015 / Rules 
and Regulations

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 257 and 261

[EPA-HQ-RCRA-2009-0640; FRL-9919-44-OSWER]
RIN-2050-AE81


Hazardous and Solid Waste Management System; Disposal of Coal 
Combustion Residuals From Electric Utilities

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA or the Agency) is 
publishing a final rule to regulate the disposal of coal combustion 
residuals (CCR) as solid waste under subtitle D of the Resource 
Conservation and Recovery Act (RCRA). The available information 
demonstrates that the risks posed to human health and the environment 
by certain CCR management units warrant regulatory controls. EPA is 
finalizing national minimum criteria for existing and new CCR landfills 
and existing and new CCR surface impoundments and all lateral 
expansions consisting of location restrictions, design and operating 
criteria, groundwater monitoring and corrective action, closure 
requirements and post closure care, and recordkeeping, notification, 
and internet posting requirements. The rule requires any existing 
unlined CCR surface impoundment that is contaminating groundwater above 
a regulated constituent's groundwater protection standard to stop 
receiving CCR and either retrofit or close, except in limited 
circumstances. It also requires the closure of any CCR landfill or CCR 
surface impoundment that cannot meet the applicable performance 
criteria for location restrictions or structural integrity. Finally, 
those CCR surface impoundments that do not receive CCR after the 
effective date of the rule, but still contain water and CCR will be 
subject to all applicable regulatory requirements, unless the owner or 
operator of the facility dewaters and installs a final cover system on 
these inactive units no later than three years from publication of the 
rule. EPA is deferring its final decision on the Bevill Regulatory 
Determination because of regulatory and technical uncertainties that 
cannot be resolved at this time.

DATES: This final rule is effective on October 14, 2015.

ADDRESSES: EPA has established three dockets for this regulatory action 
under Docket ID No. EPA-HQ-RCRA-2009-0640, Docket ID No. EPA-HQ-RCRA-
2011-0392, and Docket ID No. EPA-HQ-RCRA-2012-0028. All documents in 
these dockets are available at http://www.regulations.gov. Although 
listed in the index, some information is not publicly available, e.g., 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Certain other material, such as 
copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available either electronically in http://www.regulations.gov or in hard copy at the OSWER Docket, EPA/DC, WJC 
West Building, Room 3334, 1301 Constitution Ave. NW., Washington, DC 
20460. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., 
Monday through Friday, excluding legal holidays. The telephone number 
for the Public Reading Room is (202) 566-1744, and the telephone number 
for the OSWER Docket is 202-566-0276.

FOR FURTHER INFORMATION CONTACT: For questions on technical issues: 
Alexander Livnat, Office of Resource Conservation and Recovery, 
Environmental Protection Agency, 5304P; telephone number: (703) 308-
7251; fax number: (703) 605-0595; email address: 
[email protected], or Steve Souders, Office of Resource 
Conservation and Recovery, Environmental Protection Agency, 5304P; 
telephone number: (703) 308-8431; fax number: (703) 605-0595; email 
address: [email protected]. For questions on the regulatory impact 
analysis: Richard Benware, Office of Resource Conservation and 
Recovery, Environmental Protection Agency, 5305P; telephone number: 
(703) 308-0436; fax number: (703) 308-7904; email address: 
[email protected]. For questions on the risk assessment: Jason 
Mills, Office of Resource Conservation and Recovery, Environmental 
Protection Agency, 5305P; telephone number: (703) 305-9091; fax number: 
(703) 308-7904; email address: [email protected].
    For more information on this rulemaking please visit http://www.epa.gov/epawaste/nonhaz/industrial/special/fossil/index.htm.

SUPPLEMENTARY INFORMATION: 

A. Does this action apply to me?

    This rule applies to all coal combustion residuals (CCR) generated 
by electric utilities and independent power producers that fall within 
the North American Industry Classification System (NAICS) code 221112 
and may affect the following entities: Electric utility facilities and 
independent power producers that fall under the NAICS code 221112. The 
industry sector(s) identified above may not be exhaustive; other types 
of entities not listed could also be affected. The Agency's aim is to 
provide a guide for readers regarding those entities that potentially 
could be affected by this action. To determine whether your facility, 
company, business, organization, etc., is affected by this action, you 
should refer to the applicability criteria discussed in Unit VI.A. of 
this document If you have any questions regarding the applicability of 
this action to a particular entity, consult the person listed in the 
preceding FOR FURTHER INFORMATION CONTACT section.

B. What actions are not addressed in this rule?

    This rule does not address the placement of CCR in coal mines. The 
U.S. Department of Interior (DOI) and, as necessary, EPA will address 
the management of CCR in minefills in separate regulatory action(s), 
consistent with the approach recommended by the National Academy of 
Sciences, recognizing the expertise of DOI's Office of Surface Mining 
Reclamation and Enforcement in this area. See Unit VI of this document 
for further details. This rule does not regulate practices that meet 
the definition of a beneficial use of CCR. Beneficial uses that occur 
after the effective date of the rule need to determine if they comply 
with the criteria contained in the definition of ``beneficial use of 
CCRs.'' This rule does not affect past beneficial uses (i.e., uses 
completed before the effective date of the rule.) See Unit VI of this 
document for further details on proposed clarifications of beneficial 
use. Furthermore, CCR from non-utility boilers burning coal are also 
not addressed in this final rule. EPA will decide on an appropriate 
action for these wastes through a separate rulemaking effort. See Unit 
IV of this document for further details. Finally, this rule does not 
apply to municipal solid waste landfills (MSWLFs) that receive CCR for 
disposal or use as daily cover.

C. The Contents of This Preamble Are Listed in the Following Outline

I. Executive Summary
II. Statutory Authority
III. Background
IV. Bevill Regulatory Determination Relating to CCR From Electric 
Utilities and Independent Power Producers
V. Development of the Final Rule--RCRA Subtitle D Regulatory 
Approach

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VI. Development of the Final Rule--Technical Requirements
VII. Summary of Major Differences Between the Proposed and Final 
Rules
VIII. Implementation Timeframes for Minimum National Criteria and 
Coordination With Steam Electric ELG Rule
IX. Implementation of the Minimum Federal Criteria and State Solid 
Waste Management Plans
X. Risk Assessment
XI. Summary of Damage Cases
XII. Summary of Regulatory Impact Analysis
XIII. Uniquely Associated Wastes
XIV. Statutory and Executive Order Reviews

I. Executive Summary

    This rule establishes nationally applicable minimum criteria for 
the safe disposal of coal combustion residuals in landfills and surface 
impoundments. This section summarizes these criteria. Detailed 
discussions of the criteria and the Agency's rationale for finalizing 
these requirements are provided in Unit VI of this document.

A. What are coal combustion residuals?

    Coal combustion residuals (CCR) are generated from the combustion 
of coal, including solid fuels classified as anthracite, bituminous, 
subbituminous, and lignite, for the purpose of generating steam for the 
purpose of powering a generator to produce electricity or electricity 
and other thermal energy by electric utilities and independent power 
producers. CCR includes fly ash, bottom ash, boiler slag, and flue gas 
desulfurization materials. A description of the types of CCR can be 
found in the proposed rule (see 75 FR 35137).
    CCR is one of the largest industrial waste streams generated in the 
U.S. In 2012, over 470 coal-fired electric utilities burned over 800 
million tons of coal, generating approximately 110 million tons of CCR 
in 47 states and Puerto Rico. CCR may be generated wet or dry; however, 
this composition may change after generation. Some CCR is dewatered 
while other CCR is mixed with water to facilitate transport (i.e., 
sluiced). CCR can be sent off-site for disposal or beneficial use or 
disposed in on-site landfills or surface impoundments. In 2012, 
approximately 40 percent of the CCR generated was beneficially used, 
with the remaining 60 percent disposed in surface impoundments and 
landfills. Of that 60 percent, approximately 80 percent was disposed in 
on-site disposal units. CCR disposal currently occurs at over 310 
active on-site landfills, averaging over 120 acres in size with an 
average depth of over 40 feet, and at over 735 active on-site surface 
impoundments, averaging over 50 acres in size with an average depth of 
20 feet.

B. Background

    The Agency first solicited comments on the regulation of CCR in a 
proposed rule published in the Federal Register on June 21, 2010. This 
proposal, under the Resource Conservation and Recovery Act (RCRA), 
addressed the risks from disposal of CCR generated from the combustion 
of coal at electric utilities and from independent power producers. Two 
regulatory options were proposed. Under the first option, EPA proposed 
to list CCR as special waste subject to regulation under subtitle C of 
RCRA, when destined for disposal in landfills or surface impoundments. 
Under this option, CCR would require ``cradle-to-grave'' management and 
would be subject to requirements for, among other things, composite 
liners, groundwater monitoring, structural stability requirements, 
corrective action, closure/post closure care and financial assurance. 
States would be required to adopt the rule before it went into effect 
and a permitting program would be established with direct federal 
oversight. The subtitle C option, as proposed, would also effectively 
result in the closure of all CCR surface impoundments.
    Under the second option, EPA proposed to regulate the disposal of 
CCR under subtitle D of RCRA by issuing minimum national criteria. 
Similar to the subtitle C option, this option would require composite 
liners, groundwater monitoring, structural stability requirements, 
corrective action, and closure/post closure care. However, consistent 
with the available statutory authority under subtitle D, EPA proposed 
this option to be a self-implementing rule with no direct federal 
oversight, with an effective date six months after publication in the 
Federal Register. This option required all unlined surface impoundments 
to either retrofit to a composite liner or close within five years.
    After reviewing all the comments and additional data received, EPA 
is promulgating this final rule to regulate the disposal of CCR as 
solid waste under subtitle D of RCRA. This rule addresses the risks 
from structural failures of CCR surface impoundments, groundwater 
contamination from the improper management of CCR in landfills and 
surface impoundments and fugitive dust emissions. The rule has also 
been designed to provide electric utilities and independent power 
producers generating CCR with a practical approach for implementation 
of the requirements and has established implementation timelines that 
take into account, among other things, other upcoming regulatory 
actions affecting electric utilities and site specific practical 
realities. In order to ease implementation of the regulatory 
requirements for CCR units with state programs, EPA is also providing 
the opportunity for states to secure approval of its CCR program 
through the State Solid Waste Management Plan (``SWMP''). EPA strongly 
recommends that states take advantage of this process by revising their 
SWMPs to address the issuance of the revised federal requirements in 
this final rule, and to submit revisions of these plans to EPA for 
review. EPA would then review and approve the revised SWMPs provided 
they demonstrate that the minimum federal requirements in this final 
rule will be met. In this way, EPA's approval of a revised SWMP signals 
EPA's opinion that the state SWMP meets the minimum federal criteria.

C. What types of CCR units are covered by this rule?

    The final rule applies to owners and operators of new and existing 
landfills and new and existing surface impoundments, including all 
lateral expansions of landfills and surface impoundments that dispose 
or otherwise engage in solid waste management of CCR generated from the 
combustion of coal at electric utilities and independent power 
producers. The requirements of the rule also apply to CCR units located 
off-site of the electric utilities' or independent power producers' 
facilities that receive CCR for disposal. In addition, the rule applies 
to certain inactive CCR surface impoundments (i.e., units not receiving 
CCR after the effective date of the rule) at active electric utilities' 
or independent power producers' facilities, regardless of the fuel 
currently used at the facility to produce electricity (e.g. coal, 
natural gas, oil), if the CCR unit still contains CCR and liquids.
    The requirements do not apply to: (1) CCR landfills that ceased 
receiving CCR prior to the effective date of the rule; (2) CCR units at 
facilities that have ceased producing electricity (or electricity and 
other thermal energy) prior to the effective date of the rule; (3) CCR 
generated at facilities that are not part of an electric utility or 
independent power producer, such as manufacturing facilities, 
universities, and hospitals; (4) fly ash, bottom ash, boiler slag, and 
flue gas desulfurization materials, generated primarily from the 
combustion of fuels (including other fossil fuels) other than coal, for 
the purpose of generating electricity unless the fuel burned

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consists of more than fifty percent coal on a total heat input or mass 
input basis, whichever results in the greater mass feed rate of coal; 
(5) CCR that is beneficially used; (6) CCR placement at active or 
abandoned underground or surface coal mines; or (7) municipal solid 
waste landfills (MSWLF) that receive CCR.

D. What minimum national criteria are being established for CCR 
landfills and CCR surface impoundments?

    This final rule establishes minimum national criteria for CCR 
landfills, CCR surface impoundments, and all lateral expansions of CCR 
units including location restrictions, liner design criteria, 
structural integrity requirements, operating criteria, groundwater 
monitoring and corrective action requirements, closure and post-closure 
care requirements, and recordkeeping, notification, and internet 
posting requirements.
    1. Location Restrictions. To ensure there will be no reasonable 
probability of adverse effects on health or the environment from the 
disposal of CCR in CCR landfills, CCR surface impoundments, and all 
lateral expansions of CCR landfills and CCR surface impoundments 
(together ``CCR units''), this final rule establishes five location 
restrictions. The location criteria include restrictions relating to 
placement of CCR above the uppermost aquifer, in wetlands, within fault 
areas, in seismic impact zones, and in unstable areas. All of these 
location restrictions require the owner or operator of a CCR unit to 
demonstrate that they meet the specific criteria. As discussed 
elsewhere in this preamble, the five location restrictions apply to all 
new CCR landfills, all new and existing CCR surface impoundments, and 
all lateral expansions of CCR units; however, existing CCR landfills 
are only subject to the location restriction for unstable areas. Units 
that do not meet these restrictions can retrofit or make appropriate 
engineering demonstrations to meet this criteria. This final rule 
requires owner or operators of existing CCR units that cannot make the 
required demonstrations to close, while owners or operators of new CCR 
units and all lateral expansions who fail to make the required 
demonstrations are prohibited from placing CCR in the CCR unit.
    2. Liner Design Criteria. The final rule also establishes liner 
design criteria to help prevent contaminants in CCR from leaching from 
the CCR unit and contaminating groundwater. All new CCR landfills, new 
CCR surface impoundments, and lateral expansions of CCR units must be 
lined with composite liner, which is a liner system consisting of two 
components--a geomembrane and a two-foot layer of compacted soil--
installed in direct and uniform contact with one another. The final 
rule allows an owner or operator to construct a new CCR unit with an 
alternative composite liner, provided the alternative composite liner 
performs no less effectively than the composite liner. In addition, new 
landfills are required to operate with a leachate collection and 
removal system which is designed to remove excess leachate that may 
accumulate on top of the composite (or alternative composite) liner. 
Existing CCR landfills are not required to close or retrofit with a 
composite (or alternative composite) liner and a leachate collection 
and removal system. These existing CCR units can continue to receive 
CCR after this rule is in effect; however, the CCR units must meet all 
applicable groundwater monitoring and corrective action criteria to 
address any groundwater releases promptly. Existing CCR surface 
impoundments can also continue to operate as designed. However, if the 
existing CCR surface impoundment was not constructed with a composite 
(or alternative composite) liner or with at least two feet of compacted 
soil with a specified hydraulic conductivity, the rule would require 
the unit to retrofit or close if the CCR surface impoundment detects 
concentrations of one or more constituents listed in appendix IV at 
statistically significant levels above the groundwater protection 
standard established by the rule.
    3. Structural Integrity Requirements. To help prevent the damages 
associated with structural failures of CCR surface impoundments, the 
final rule establishes structural integrity criteria for new and 
existing surface impoundments (and all lateral expansions) as part of 
the design criteria. While the applicability of the structural 
integrity requirements to individual CCR surface impoundments vary 
depending on factors such as dike heights and the potential for loss of 
life, environmental damage and economic loss if there is a dike 
failure, the final rule establishes requirements for owner or operators 
to conduct a number of structural integrity-related assessments 
regularly. These include: (1) Conducting periodic hazard potential 
classification assessments to assess the potential adverse incremental 
consequences that would occur if there was a failure of the CCR surface 
impoundment; (2) conducting periodic structural stability assessments 
by a qualified professional engineer to document whether the design, 
construction, operation and maintenance is consistent with recognized 
and generally accepted good engineering practices; and (3) conducting 
periodic safety factor assessments to document whether the CCR unit 
achieves minimum factors of safety for slope stability. If a CCR unit 
required to conduct a safety factor assessment fails to demonstrate 
that the unit achieves the specified factors of safety, the owner or 
operator must close the unit. In addition, certain CCR surface 
impoundments are required to develop an emergency action plan which 
defines the events and circumstances involving the CCR unit that 
represent an emergency and identifies the actions that will be taken in 
the event of a safety emergency.
    4. Operating Criteria. The operating criteria include air criteria 
for all CCR units, run-on and run-off controls for CCR landfills, 
hydrologic and hydraulic capacity requirements for CCR surface 
impoundments, and periodic inspection requirements for all CCR units. 
These criteria address the day-to-day operations of CCR units and are 
established to prevent health and environmental impacts from CCR units. 
The air criteria address the pollution caused by windblown dust from 
CCR units, and require owners and operators to minimize CCR from 
becoming airborne at the facility. The run-on controls for CCR 
landfills minimize the amount of surface water entering the unit that 
will help prevent erosion, surface discharges of CCR in solution or 
suspension, and will mitigate the generation of landfill leachate, 
while run-off controls help prevent erosion, protect downstream surface 
water from releases from the unit, and minimize storm water run-off 
volume and velocity. CCR surface impoundments are subject to hydrologic 
and hydraulic capacity requirements to ensure the unit can safely 
handle flood flows, which will help prevent uncontrolled overtopping of 
the unit or erosion of the materials used to construct the surface 
impoundment. The final rule also requires periodic inspections of CCR 
units to identify any appearance of structural weakness or other 
conditions that are not consistent with recognized and generally 
accepted good engineering standards.
    5. Groundwater Monitoring and Corrective Action. The groundwater 
monitoring and corrective action criteria require an owner or operator 
of a CCR unit to install a system of monitoring wells and specify 
procedures for sampling these wells, in addition to methods for 
analyzing the groundwater data collected, to detect the presence of

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hazardous constituents (e.g., toxic metals) and other monitoring 
parameters (e.g., pH, total dissolved solids) released from the units. 
The final rule establishes a groundwater monitoring program consisting 
of detection monitoring, assessment monitoring and corrective action. 
Once a groundwater monitoring system and groundwater monitoring program 
has been established for a CCR unit, the owner or operator must conduct 
groundwater monitoring and, if the monitoring demonstrates an 
exceedance of a groundwater protection standard for any of the 
identified constituents in CCR, must initiate corrective action.
    6. Closure and Post-Closure Requirements. The closure and post-
closure care criteria require all CCR units to close in accordance with 
specified standards and to monitor and maintain the units for a period 
of time after closure, including the groundwater monitoring and 
corrective action programs. These criteria are essential to ensuring 
the long-term safety of closed CCR units. Closure of a CCR unit must be 
completed either by leaving the CCR in place and installing a final 
cover system or through removal of the CCR and decontamination of the 
CCR unit. The final rule establishes timeframes to initiate and 
complete closure activities, and authorize owners or operators to 
obtain time extensions due to circumstances beyond the facility's 
control. As discussed elsewhere in this preamble, the rule also 
establishes alternative closure procedures in situations where an owner 
or operator is closing a CCR unit, but has no alternative CCR disposal 
capacity or is permanently closing the coal-fired boiler unit in the 
foreseeable future. Finally, owners and operators are required to 
prepare closure and post-closure care plans describing these 
activities.
    7. Record Keeping, Notification, and Internet Posting Requirements. 
The final rule requires owners or operators of CCR units to record 
certain information in the facility's operating record. In addition, 
owners and operators are required to provide notification to States 
and/or appropriate Tribal authorities when the owner or operator places 
information in the operating record, as well as to maintain a publicly 
accessible internet site for this information.
    8. Severability. EPA intends that the provisions of this rule be 
severable. In the event that any individual provision or part of this 
rule is invalidated, EPA intends that this would not render the entire 
rule invalid, and that any individual provisions that can continue to 
operate will be left in place. The following tables provide a summary 
of the specific technical requirements applicable to existing and new 
CCR landfills, existing and new CCR surface impoundments, and all 
lateral expansions of CCR units.

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E. When must owners or operators of CCR landfills and CCR surface 
impoundments meet the minimum national criteria?

    The rule becomes effective six months after the publication date of 
this rule. The final rule establishes timeframes for certain technical 
criteria based on the amount of time determined to be necessary to 
implement the requirements (e.g., installing the groundwater monitoring 
wells and establishing the groundwater monitoring program). In 
establishing these timeframes, EPA accounted for other Agency 
rulemakings that are anticipated to also affect the owners or operators 
of CCR units, namely the Effluent Limitations Guidelines and Standards 
for the Steam Electric Power Generating Point Source Category (78 FR 
34432; proposed rule issued June 7, 2013) and the Carbon Pollution 
Emission Guidelines for Existing Stationary Sources: Electric Utility 
Generating Units (79 FR 34830; proposed rule issued June 18, 2014). 
Specifically, EPA developed implementation timeframes that would ensure 
that owner or operators of CCR units would not be required to make 
decisions about those CCR units without first understanding the 
implications that such decisions would have for meeting the 
requirements of all applicable EPA rules.

F. Deferral of Final Bevill Determination

    This rule defers a final Bevill Regulatory Determination with 
respect to CCR that is disposed in CCR landfills and CCR surface 
impoundments until additional information is available on a number of 
key technical and policy questions. This includes information needed to 
quantify the risks of CCR disposal, and the potential impacts of recent 
Agency regulations on the chemical composition of CCR. The Agency also 
needs further information on adequacy of the state programs.

G. Beneficial Use

    The final rule retains the Bevill exclusion for CCR that is 
beneficially used, and provides a definition of beneficial use to 
distinguish between beneficial use and disposal.

H. Implementation

    Because the regulations have been promulgated under sections 
1008(a), 4004(a), and 4005(a) of RCRA, the rule does not require 
permits, does not require states to adopt or implement these 
requirements, and EPA cannot enforce these requirements. Instead, 
states or citizens can enforce the requirements of this rule under 
RCRA's citizen suit authority; the states can also continue to enforce 
any state regulation under their independent state enforcement 
authority. (For a more detailed discussion of EPA authorities under 
RCRA and its relationship to this rule, see 75 FR 35128, June 21, 
2010). EPA recognizes the significant role states play in implementing 
these requirements and EPA strongly encourages states to revise their 
SWMPs to show how these new criteria will be implemented. EPA would 
then review and approve the revised plan provided it demonstrates that 
the minimum federal requirements in this final rule will be met. In 
this way, EPA's approval of a revised plan signals EPA's opinion that 
the State's SWMP meets the minimum federal criteria. For a more 
detailed discussion on the role of the states in implementing this 
rule, please refer to Unit IX of this document.

I. Characterization of Baseline Affected Entities and CCR Management 
Practices

    This action will affect CCR generated by coal-fired electric 
utility plants in the NAICS industry code 221112 (i.e., the ``Fossil 
Fuel Electric Power Generation'' industry within the NAICS 22 
``Utilities'' sector code). Based on 2012 electricity generation data 
published by the Energy Information Administration (EIA), the 
Regulatory Impact Analysis (RIA) for this action estimated that a total 
of 478 operational coal-fired electric utility plants in this NAICS 
code could be affected by this action. These plants are owned by 242 
entities consisting of 166 companies, 17 cooperative organizations, 58 
state or local governments, and one federal agency. A sub-total of 81 
of the 242 owner entities (i.e., 33 percent may be classified as small 
businesses, small organizations, or small governments). The 478 coal-
fired electric utility plants operate a total of 1,045 CCR management 
units (735 surface impoundments and 310 landfills). These 478 plants 
generate 110 million tons of CCR, consisting of 201 plants (42 percent) 
disposing in on-site landfills, 169 (35 percent) disposing in on-site 
ponds, and 197 (41 percent) disposing in off-site landfills. Because 
some plants use more than one CCR management method, these plant counts 
exceed 478 total plants. In addition, 293 of the 478 plants supply CCR 
for beneficial uses in at least 14 industries. Nineteen of the 293 
plants solely supply CCR for beneficial uses. As of 2012, CCR 
beneficial uses (i.e., industrial applications) involved about 52 
million tons annually.

J. Summary of Estimated Regulatory Costs and Benefits

    The EPA estimated future regulatory compliance costs and expected 
future human health and environmental protection benefits can be found 
in the RIA document which is available from the docket for this action. 
The estimated costs and benefits for the CCR rule are incremental to 
the baseline (current) practices by the electric utility industry to 
manage CCR in accordance with (a) existing state government 
environmental regulations and (b) utility company CCR management 
methods.
    The RIA estimates the cost of the rule over a 100 year period 
because of: (1) CCR unit lifespans (40 years to 80 years of age); (2) 
groundwater migration (estimated time to peak potential exposures of 
CCR through groundwater migration to drinking water wells is 75 years); 
and (3) latency periods for onset of illness after exposure to CCR, 
which can average 20 years.
    The table below summarizes the estimated incremental costs and 
benefits of the rule. The RIA estimates costs to comply with the 12 
pollution control requirements associated with the rule, as well as 
estimated monetized values for 11 expected benefits, and discusses 11 
other non-monetized benefits.

       EPA Estimated Incremental Costs & Benefits of the CCR Rule
       [millions 2013$ over 100-year period of analysis 2015-2114]
------------------------------------------------------------------------
                                            3% Discount     7% Discount
                                               rate            rate
------------------------------------------------------------------------
A. Annualized Values
    A1. Total Costs.....................            $735            $509
    A2. Total monetized benefits........            $294            $236
    A3. Net Benefits (A2-A1)............          ($441)          ($441)
    A4. Benefit to Cost Ratio (A3/A1)...            0.40            0.46

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B. Present Value
    B1. Total Costs.....................         $23,200          $7,260
    B2. Total monetized benefits........          $8,710          $3,360
    B3. Net Benefits (B2-B1)............       ($14,490)        ($3,900)
    B4. Benefit to Cost Ratio (B2/B1)...            0.38            0.46
------------------------------------------------------------------------

II. Statutory Authority

    These regulations are established under the authority of sections 
1006(b), 1008(a), 2002(a), 3001, 4004, and 4005(a) of the Solid Waste 
Disposal Act of 1970, as amended by the Resource Conservation and 
Recovery Act of 1976 (RCRA), as amended by the Hazardous and Solid 
Waste Amendments of 1984 (HSWA), 42 U.S.C. 6906(b), 6907(a), 6912(a), 
6944 and 6945(a).
    RCRA section 1006(b) directs EPA to integrate the provisions of 
RCRA for purposes of administration and enforcement and to avoid 
duplication, to the maximum extent practicable, with the appropriate 
provisions of other EPA statutes. Section 1006(b) conditions EPA's 
authority to reduce or eliminate RCRA requirements on the Agency's 
ability to demonstrate that the integration meets RCRA's protectiveness 
mandate (42 U.S.C. 6005(b)(1)). See Chemical Waste Management v. EPA, 
976 F.2d 2, 23, 25 (D.C. Cir. 1992).
    RCRA section 1008(a) authorizes EPA to publish ``suggested 
guidelines for solid waste management.'' 42 U.S.C. 6907(a). RCRA 
defines solid waste management as ``the systematic administration of 
activities which provide for the collection, source separation, 
storage, transportation, transfer, processing, treatment, and disposal 
of solid waste.'' 42 U.S.C. 6903(28).
    Pursuant to section 1008(a)(3), the guidelines are to include the 
minimum criteria to be used by the states to define the solid waste 
management practices that constitute the open dumping of solid waste or 
hazardous waste and are prohibited as ``open dumping''under section 
4005. Only those requirements promulgated under the authority of 
section 1008(a)(3) are enforceable under section 7002 of RCRA.
    RCRA section 4004 generally requires EPA to promulgate regulations 
containing criteria for determining which facilities shall be 
classified as sanitary landfills (and therefore not ``open dumps''). 
The statute directs that, ``at a minimum, the criteria are to ensure 
that units are classified as sanitary landfills only if there is no 
reasonable probability of adverse effects on health or the environment 
from disposal of solid wastes at such facility.'' 42 U.S.C. 6944(a).
    RCRA section 4005(a), entitled ``Closing or upgrading of existing 
open dumps'' generally establishes the key implementation and 
enforcement provisions applicable to EPA regulations issued under 
sections 1008(a) and 4004(a). Specifically, this section prohibits any 
solid waste management practices or disposal of solid waste that does 
not comply with EPA regulations issued under RCRA section 1008(a) and 
4004(a). 42 U.S.C. 6944(a). See also 42 U.S.C. 6903(14) (definition of 
``open dump''). This prohibition takes effect ``upon promulgation'' of 
any rules issued under section 1008(a)(3) and is enforceable through a 
citizen suit brought pursuant to section 7002. As a general matter, 
this means that facilities must be in compliance with any EPA rules 
issued under this section no later than the effective date of such 
rules, or be subject to a citizen suit for ``open dumping'' 42 U.S.C. 
6945. RCRA section 4005 also directs that open dumps, i.e., facilities 
out of compliance with EPA's criteria, must be ``closed or upgraded.''
    Section 7004 lays out specific requirements relating to public 
participation in regulatory actions under RCRA. Subsection (b) provides 
that ``[p]ublic participation in the . . . implementation, and 
enforcement of any regulation under this chapter shall be provided for, 
encouraged, and assisted by the Administrator.'' 42 U.S.C. 6974(b).

A. Regulation of Solid Wastes Under RCRA Subtitle D

    Solid wastes that are neither a listed nor characteristic hazardous 
waste are subject to the requirements of RCRA subtitle D. Subtitle D of 
RCRA establishes a framework for federal, state, and local government 
cooperation in controlling the management of non-hazardous solid waste. 
The federal role is to establish the overall regulatory direction, by 
providing minimum nationwide standards that will protect human health 
and the environment, and to provide technical assistance to states for 
planning and developing their own environmentally sound waste 
management practices. The actual planning and any direct implementation 
of solid waste programs under RCRA subtitle D, however, remains a state 
and local function, and the Act envisions that states will devise 
programs to deal with state-specific conditions and needs. EPA has no 
role in the planning and direct implementation of the minimum national 
criteria or solid waste programs under RCRA subtitle D, and has no 
authority to enforce the criteria. However, states are not required to 
adopt solid waste management programs, and thus, Congress developed a 
statutory structure that creates incentives for states to implement and 
enforce the federal criteria, but that does not necessarily rely on or 
require a regulatory entity to oversee or implement them. While 
Congress developed the statutory structure to create incentives for 
states to implement and enforce the federal criteria, it does not 
require them to do so. As a result, subtitle D is also structured to be 
self-implementing.
    RCRA sections 1008(a)(3) and 4004(a) delegate broad authority to 
EPA to establish regulations governing the management of solid waste. 
Under section 4004(a) EPA is charged with establishing requirements to 
ensure that facilities will be classified as sanitary landfills ``only 
if there is no reasonable probability of adverse effects on health or 
the environment from the disposal of solid waste'' at the facility. Or 
in other words, under section 4004(a) EPA is charged with issuing 
regulations to address all ``reasonable probabilities of adverse 
effects'' (i.e., all reasonably anticipated risks) to health and the 
environment from the disposal of solid waste. Section 1008(a)(3) 
expands EPA's authority to address the risks from any of the listed 
activities. Specifically, EPA is authorized to establish requirements 
applicable to ``storage, transportation, transfer, processing, 
treatment, and disposal of solid waste.'' (42 U.S.C. 6907(a), 
6903(28)).

[[Page 21311]]

    EPA interprets the standard in section 4004(a) to apply equally to 
criteria issued under sections 1008(a)(3) and 4004(a); namely that the 
criteria must ensure that a facility is to be classified as a sanitary 
landfill, and thus allowed to continue to operate, ``only if there is 
no reasonable probability of adverse effects on health or the 
environment'' from either the disposal or other solid waste management 
practices at the facility. Thus, under the combined authority conferred 
by sections 1008(a)(3) and 4004(a), a facility is an ``open dump'' if 
it engages in any activity involving the management of solid waste that 
does not meet the standard in section 4004(a); or in other words, any 
activity involved with the management of solid waste that presents a 
reasonable probability of causing adverse effects on health or the 
environment. EPA also interprets these provisions to authorize the 
establishment of criteria that define the manner in which facilities 
upgrade or close, consistent with the standard in section 4004(a), to 
ensure there will be no reasonable probability of adverse effects on 
health or the environment.
    As discussed previously, Congress created a regulatory structure 
that limited EPA's role to the creation of national criteria that would 
operate even in the absence of a regulatory entity to oversee or 
implement the criteria. Under RCRA section 4005(a), upon promulgation 
of criteria under section 1008(a)(3), any solid waste management 
practice or disposal of solid waste that constitutes the ``open 
dumping'' of solid waste is prohibited. The federal standards apply 
directly to the facility (are self-implementing) and facilities are 
directly responsible for ensuring that their operations comply with 
these requirements. States are not required to incorporate or implement 
these requirements under any state permitting program or other state 
law requirement, and EPA is not authorized to impose such requirements, 
directly or indirectly on the states. States and citizens may enforce 
this prohibition (and therefore, the federal criteria) using the 
authority under RCRA section 7002.\1\
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    \1\ EPA also may act if the handling, storage, treatment, 
transportation, or disposal of such wastes may present an imminent 
and substantial endangerment to health or the environment, pursuant 
to RCRA section 7003.
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    The statute also creates incentives to states to implement the 
criteria. Chief among the incentives is a greater role in 
implementation and enforcement of the solid waste program, including to 
a limited extent the ability to give facilities that are operating 
within their state additional time to come into compliance with newly 
promulgated EPA criteria. Specifically, if the facility is located in a 
state with a plan that was approved under section 4003(b), the state 
may grant the facility an extension of up to five years from the date 
the final rule was published in the Federal Register to come into 
compliance with EPA regulations, provided: (a) The facility is listed 
in a state inventory of open dumps; and (b) the facility has 
demonstrated that it has considered other public or private 
alternatives for solid waste management to comply with the prohibition 
on open dumping and is unable to utilize such alternative. For 
facilities that meet these requirements, the state may establish a 
``schedule for compliance'' which specifies a schedule of remedial 
measures, including an enforceable sequence of actions or operations, 
leading to compliance with the requirements ``within a reasonable time 
(not to exceed five years from the date of publication of criteria 
under section [1008] (a)(3) of this title).'' 42 U.S.C. 6945(a).
    As a consequence of this statutory structure--the requirement to 
establish national criteria and the absence of any requirement for 
direct regulatory oversight--to establish the criteria EPA must 
demonstrate, through factual evidence available in the rulemaking 
record, that the final rule will achieve the statutory standard (``no 
reasonable probability of adverse effects on health or the 
environment'') at all sites subject to the standards based exclusively 
on the final rule provisions. This means that the standards must 
account for and be protective of all sites, including those that are 
highly vulnerable.

III. Background

A. EPA's Proposed Rule

    On June 21, 2010 (75 FR 35128), EPA proposed to regulate CCR under 
RCRA to address the risks from the disposal of CCR generated from the 
combustion of coal at electric utilities and independent power 
producers. As described in the proposal, CCR are residuals generated 
from the combustion of coal and include fly ash, bottom ash, boiler 
slag (all composed predominantly of silica and aluminosilicates), and 
flue gas desulfurization (FGD) materials (predominantly Ca-
SOX compounds) and can be managed in either wet (surface 
impoundments) or dry (landfills) disposal systems. EPA noted in the 
proposed rule that the constituents of most environmental concern in 
CCR are metals, such as antimony, arsenic, barium, beryllium, cadmium, 
chromium, lead, mercury, nickel, selenium, silver and thallium. EPA 
also presented data showing numerous instances where these constituents 
(especially arsenic) have leached at levels of concern from unlined and 
inadequately clay-lined landfills and surface impoundments.
    In the proposal, EPA revisited its August 1993 and May 2000 Bevill 
Regulatory Determinations regarding CCR generated at electric utilities 
and independent power producers. The results from this effort led the 
Agency to consider two primary options for the management of CCR and 
thus, propose two alternative regulatory strategies. Under the first 
option, EPA proposed to reverse its August 1993 and May 2000 Bevill 
Regulatory Determinations (58 FR 42466 and 65 FR 32214 respectively) 
regarding CCR and to list these residuals as special wastes subject to 
regulation under subtitle C of RCRA when they are destined for disposal 
in landfills or surface impoundments. Under this proposed option, CCR 
would be regulated from the point of generation to the point of final 
disposition and would generally be subject to the existing subtitle C 
regulations at 40 CFR parts 260 through 268, as well as the permitting 
requirements in 40 CFR part 270, and the state authorization process in 
40 CFR parts 271-272. Among other things, the regulatory requirements 
included waste characterization, location restrictions, liner and, if 
applicable, leachate collection requirements for land disposal units, 
fugitive dust controls, groundwater monitoring and corrective action 
requirements, closure and post-closure care requirements, financial 
assurance, permitting requirements, and recordkeeping and reporting 
requirements. This option also imposed requirements on generators and 
transporters of CCR destined for disposal, including manifesting (if 
the CCR destined for disposal is sent off-site). However, in light of 
practical difficulties in implementing certain subtitle C regulatory 
requirements, EPA also proposed to revise selected requirements under 
the subtitle C option. Consequently, EPA proposed, pursuant to its 
authority under section 3004(x) of RCRA, modifications to the CCR 
landfill and surface impoundment liner and leak detection system 
requirements, the effective dates for the land disposal restrictions, 
and the surface impoundment retrofit requirements. EPA also proposed to 
establish new land disposal prohibitions and treatment standards for 
both wastewater and non-wastewater forms of CCR. In part, the proposed

[[Page 21312]]

modifications to the treatment standards would result in the closure of 
existing surface impoundments and the prohibition of all new surface 
impoundments. (See 75 FR 35128 for a complete discussion of this 
proposed option).
    Under the second option, EPA proposed to retain the August 1993 and 
May 2000 Bevill Regulatory Determinations and to regulate CCR disposal 
under subtitle D of RCRA by issuing national minimum criteria to ensure 
the safe disposal of CCR in surface impoundments and landfills. Under 
this option, CCR would remain classified as a non-hazardous RCRA solid 
waste. EPA proposed to establish technical requirements, many of which 
were nearly identical to the technical standards proposed under the 
subtitle C option. The technical standards included, among other 
things, locations standards, liner and leachate collection 
requirements, groundwater monitoring and corrective action standards 
for releases from the units, operating criteria, such as fugitive dust 
control, closure and post-closure care requirements, and recordkeeping 
and reporting requirements. Under this option, EPA did not propose to 
establish regulatory requirements that would restrict the generation, 
transportation, storage, or treatment of CCR prior to disposal, nor did 
EPA propose to establish financial assurance requirements under 
RCRA.\2\ Also, because of subtitle D's limitations, the proposed rule 
did not require permits; nor could EPA enforce the national minimum 
criteria. Rather, states or citizens could enforce the national minimum 
criteria under RCRA's citizen suit authority, and states could continue 
to enforce any state regulation that applies to CCR under their 
independent state enforcement authority.
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    \2\ In the proposal, the Agency stated that the RCRA subtitle D 
alternative did not include proposed financial responsibility 
requirements and that any such requirements would be proposed 
separately. The Agency solicited comment on whether financial 
responsibility requirements under CERCLA section 108(b) should be a 
key Agency focus under a RCRA subtitle D approach. While the Agency 
received numerous comments urging the Agency to establish financial 
responsibility as part of the subtitle D option, the CERCLA 108(b) 
option did not receive significant support. As discussed in the 
proposal and reiterated here, EPA will not be requiring financial 
assurance requirements as part of this rule. The Agency however will 
continue to investigate the use of other statutory authorities 
(e.g., CERCLA) to establish financial responsibility requirements 
for owners or operators of CCR landfills, CCR surface impoundments 
and any lateral expansion.
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    The subtitle D proposed option was designed to be self-
implementing, meaning that the requirements were such that facilities 
could comply with the regulatory requirements without the need to 
interact with a regulatory authority. EPA sought to enhance the 
protectiveness of the proposed option by requiring certified 
demonstrations by an independent registered professional engineer to 
provide verification that the regulatory requirements were being 
adhered to. In addition, the option provided for state and public 
notification of the certifications, as well as required posting of 
certain information on a Web site maintained by the facility and in the 
operating record. (See 75 FR 35128 for a complete discussion of this 
proposed option).\3\
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    \3\ While EPA cannot enforce the subtitle D proposed rules, EPA 
can take action under section 7003 of RCRA to abate conditions that 
``may present an imminent and substantial endangerment to health or 
the environment.'' EPA can also use the imminent and substantial 
endangerment authorities under the CERCLA, or under other federal 
authorities to address those circumstances where a unit(s) may pose 
a threat.
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    The Agency also described other alternatives considered. For 
example, one subtitle D option, called ``D-prime'' was structured so 
that all existing CCR surface impoundments could continue to receive 
CCR after the effective date of the rule for the remainder of the 
unit's useful life, irrespective of their liner type, provided the 
other provisions of the subtitle D option were met (e.g., groundwater 
monitoring). (See 75 FR 35128 for a complete discussion of this and 
other possible regulatory alternatives on which the Agency solicited 
comment.)
    Under both the subtitle C and subtitle D alternatives, EPA proposed 
establishing dam safety requirements to address the structural 
integrity of surface impoundments. EPA also proposed not to change the 
May 2000 Regulatory Determination for beneficially used CCR, which are 
currently exempt from the hazardous waste regulations under section 
3001(b)(3)(A) of RCRA. EPA also did not propose to address the 
placement of CCR in mines, or non-minefill uses of CCR at coal mine 
sites.
    In addition to proposing these two regulatory options for the 
management of CCR, EPA identified many issues on which it solicited 
comment, information, and data. Certain solicitations were very 
general, such as comments on alternative options for regulating CCR, 
while other requests for comment were very specific in nature, for 
example, whether clay liners designed to meet a specified hydraulic 
conductivity might perform differently in practices than modeled in the 
risk assessment. (The Agency requested comment on issues throughout the 
preamble; however specific issues for which EPA solicited comment can 
be found at 75 FR 35221-34224.)

B. Comments Received on the Proposed Rule

    The Agency received over 450,000 comments on the proposed rule. The 
majority of the commenters focused on which regulatory path the Agency 
should pursue for regulating CCR, i.e., RCRA's subtitle C or subtitle 
D. A number of commenters, however, argued that no additional 
regulation was necessary and that the states were adequately regulating 
the management of CCR. Generally, environmental groups and individual 
citizens favored a subtitle C rule arguing that state programs have 
failed and damage cases are growing in number. State organizations, 
individual states, and industry groups (electric utilities, recycling 
firms, trade associations), largely favored a subtitle D rule with a 
permitting program.
    One area that received extensive comment was the re-evaluation of 
the eight Bevill study factors.\4\ Numerous commenters provided 
detailed analysis related to the study factors and provided their own 
interpretations of the data (e.g., state programs and damage cases). 
Other areas that received significant comment included beneficial use 
and the risk assessment.
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    \4\ In considering whether to retain or to reverse the August 
1993 and May 2000 Regulatory Determinations regarding the Bevill 
exemption of CCR destined for disposal, the Agency re-examined the 
RCRA section 8002(n) study factors. These eight study factors are: 
(1) Source and volumes of CCR generated per year; (2) present 
disposal and utilization practices (which includes evaluation of 
existing state regulatory oversight and beneficial use); (3) 
potential danger, if any, to human health and the environment from 
the disposal and reuse of CCR; (4) documented cases in which danger 
to human health or the environment from surface runoff or leachate 
has been proved; (5) alternatives to current disposal methods; (6) 
the cost of such alternative disposal methods; (7) the impact of the 
alternative disposal methods on the use of coal and other natural 
resources; and (8) the current and potential utilization of CCR (see 
75 FR 35128).
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    Discussion of the specific comments germane to this rulemaking are 
provided in the relevant sections of this document.

C. Other Actions During Which Comment Was Taken

1. Public Hearings
    EPA conducted eight public hearings during the months of August, 
September, and October in 2010. There were over 1300 individual 
speakers at the eight public hearings that commented on the proposed 
rule. Testimony at the public hearings focused generally on whether EPA

[[Page 21313]]

should adopt a subtitle C or subtitle D approach for regulating CCR. 
Many commenters were also concerned with fugitive dust emissions and 
the affect these emissions had on their health and overall well-being. 
Other commenters were concerned that adopting a subtitle C rule for CCR 
would negatively affect the beneficial use of the material. In addition 
to their testimonies that were entered into the rulemaking record, over 
1200 additional documents were submitted in hard copy and entered into 
the docket (see EPA-HQ-RCRA-2009-0640).
2. Notices of Data Availability
    Subsequent to the proposed rule, the Agency published several 
Notices of Data Availability (NODAs), the first on October 21, 2010, 
(75 FR 64974); the second on October 12, 2011 (76 FR 63252) and the 
third on August 2, 2013 (78 FR 46940). Specifically:
     The first NODA invited comment on the responses EPA 
received on Information Collection Requests that were sent to electric 
utilities on their CCR surface impoundments, as well as reports and 
materials related to the site assessments EPA had conducted on a subset 
of these impoundments.
     The second NODA invited comment on a number of topics, 
including (1) chemical constituent data from coal combustion residuals; 
(2) facility and waste management unit data; (3) information on 
additional alleged damage cases; (4) the adequacy of state programs; 
and (5) beneficial use.
     The third NODA invited comment on (1) supplemental data 
for the risk assessment; (2) supplemental data for the RIA; (3) 
information regarding large-scale fill; and (4) data on the CCR 
Assessment Program. EPA also sought comment on two technical issues 
associated with the requirements for CCR management units: closure 
requirements and regulation of overfills (i.e., CCR management units 
built directly over pre-existing CCR landfills or CCR surface 
impoundments).
    Specific comments received on each of the three NODAs are discussed 
in the relevant sections of this rule.
3. Effluent Limitations Guidelines and Standards for the Steam Electric 
Power Generating Point Source Category Proposed Rule
    On June 7, 2013 (78 FR 34432), EPA proposed a regulation that would 
strengthen the controls on discharges from certain steam electric power 
plants by revising the technology-based effluent limitation guidelines 
(ELG) and standards for the steam electric power generating point 
source category. As part of this proposal, EPA discussed its current 
thinking on how a final RCRA CCR rule might be aligned and structured 
to account for any final requirements adopted under the ELG for the 
Steam Electric Power Generating point source category. Two primary 
means of integrating the two rules were discussed: (1) Coordinating the 
design of any final substantive CCR regulatory requirements and (2) 
coordinating the timing and implementation of the rules to allow 
facilities to coordinate their compliance planning and implementation 
and to protect electricity reliability for consumers. EPA stated that 
consistent with RCRA section 1006(b), effective coordination of any 
final RCRA requirements with the ELG requirements would be sought in 
order to minimize the overall complexity of the two regulatory 
structures, and facilitate implementation of engineering, financial, 
and permitting activities. EPA solicited comments on how any final CCR 
final rule might be aligned and structured to account for any final 
requirements adopted under the ELG for the Steam Electric Power 
Generation point source category.

D. EPA's CCR Assessment Program

    In March 2009, the Agency's CCR Assessment Program (herein referred 
to as the Assessment Program) was initiated. This effort was in 
response to the December 22, 2008 dike failure of a coal ash 
impoundment at the Tennessee Valley Authority (TVA) Kingston Fossil 
Plant in Harriman, Tennessee where over one billion gallons of coal ash 
slurry were released, affecting more than 300 acres, including 
residences and infrastructure. The TVA Kingston impoundment failure 
ignited a nation-wide concern over the safety of coal ash impoundments; 
and EPA was tasked with determining whether the potential existed for 
similar impoundment failures at other coal-fired power plants. In 
response, EPA developed the Assessment Program to evaluate the 
structural stability and safety of all coal ash impoundments throughout 
the country.\5\ As of September 2014, 559 impoundments had been 
assessed at over 230 coal-fired power plants.
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    \5\ The focus of the Assessment Program was to assess the 
structural integrity of CCR impoundments meeting specified criteria. 
The Agency did not include, as part of its evaluation, the 
assessment of other conditions/characteristics of the impoundment 
that may present potential risks to human health or the environment, 
i.e., groundwater contamination due to an insufficient liner design.
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    The Assessment Program began as a separate effort from the 
development of this final rule.\6\ However, the information and 
experience developed in carrying out the site assessments during the 
Assessment Program is directly relevant to many of the issues addressed 
in this rulemaking, and provide further technical support for many of 
the technical criteria. Consequently, many of the final technical 
criteria were developed in direct response to findings from the site 
assessments. For example, several of the technical criteria contained 
in the proposed rule were modified to account for the widely accepted 
engineering methodologies and practices used in conducting the site 
assessments, as well as current facility practices documented during 
the assessments. In a few instances, the criteria were supplemented to 
better align the technical requirements with the Assessment Program. 
Included among the final criteria that directly rely on the Assessment 
Program are the provisions relating to structural integrity assessments 
to address factors of safety, periodic reassessments, hazard potential 
classifications, and the hydrologic and hydraulic capacity of CCR 
surface impoundments. These requirements are further discussed in Unit 
VI of this preamble.
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    \6\ EPA issued two Notices of Data Availability (75 FR 35128 
(October 21, 2010) and 78 FR 46940 (August 2, 2013)) specifically 
soliciting comment on the information generated by the Assessment 
Program and the materials posted on our Web site.
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    The Assessment Program focused on impoundments meeting four general 
criteria that were designed to identify the units most likely to 
present the same risks as the collapsed TVA impoundment: (1) Above 
ground or diked; (2) of sufficient height to be susceptible to 
structural failure (i.e., six feet); (3) receiving CCR; and (4) located 
at operating coal-fired power plants selling power to the electric 
grid. Also included in the assessments were a number of inactive 
impoundments, i.e., impoundments not receiving CCR but still containing 
CCR and/or liquid. The Agency included these inactive units in the 
assessment reasoning that these units would be as susceptible to 
structural failure as units currently receiving CCR, given that they 
still contained CCR and maintained an ability to impound liquid (i.e., 
the unit had not been breached). The Assessment Program did not 
evaluate, however, incised (not having above ground berms or dikes) 
impoundments or landfills (not containing liquid slurried CCR wastes). 
EPA chose not to assess these units because they did not share the 
characteristics of

[[Page 21314]]

impoundments likely to raise concern for catastrophic releases, and 
because no known catastrophic structural failures were associated with 
these types of units.
    Prior to initiating the assessments, EPA consulted with two key dam 
safety organizations, the Association of State Dam Safety Officials 
(ASDSO) and the Mine Safety and Health Administration (MSHA) to better 
understand how these federal and state dam inspection programs 
operated, including how earthen dams and impoundments were assessed.\7\ 
These groups provided the Agency with critical insight and information 
for inspecting and evaluating CCR impoundments. The Agency also 
reviewed various technical documents relating to dam safety and 
conducting impoundment inspections, many of which were recommended by 
these organizations. They were: (1) U.S. Army Corp of Engineers (USACE) 
2008 National Inventory of Dams (NIDS); (2) Federal Emergency 
Management Agency's (FEMA) Federal Guidelines for Dam Safety--Hazard 
Potential Classification System for Dams (April 2004); (3) FEMA's Risk 
Prioritization Tool for Dams User Manual (March 2008); (4) MSHA's 
Handbook (PH07-01); (5) MSHA's Coal Mine Impoundment Inspection and 
Plan Review Handbook (October 2007); and (6) MSHA's Engineering and 
Design Manual: Coal Refuse Disposal Facility (May 2009); (7) ASDSO's 
``Summary of State Dam Safety Laws and Regulations,'' (2000); (8) 
ASDSO's ``Owner Responsible Periodic Inspection Guidance,'' (2005); (9) 
``Guidelines for Inspections of Existing Dams.'' New Jersey Department 
of Environmental Protection--Dam Safety (January 2008).
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    \7\ ASDSO identified for EPA key documents to review including 
Federal Energy Regulatory Commission (FERC) and MSHA guidance.
---------------------------------------------------------------------------

    In developing the criteria that were used to conduct the 
assessments, a standard rating system was developed to classify the 
units' suitability for continued safe and reliable operation. EPA 
modeled its impoundment condition rating criteria on those developed by 
the State of New Jersey (see reference above).
1. Conducting the Site Assessments
    In order to prioritize the assessments, a preliminary hazard 
potential classification ranking was identified for each impoundment, 
based on criteria developed by the FEMA and found generally in USACE's 
NID. EPA elected to evaluate first those impoundments with a high 
hazard potential classification, which signifies that a failure or mis-
operation of the unit would probably result in the loss of human life.
    Upon initiation of the Assessment Program, every owner or operator 
of a CCR impoundment was contacted by the Agency and supplied with 
information on the objectives of the assessment and how the assessments 
were to be conducted. Assessments were conducted in rounds, consisting 
of groups of 12-26 facilities per round.\8\ Prior to each site 
assessment, to ensure uniformity throughout the study, a statement of 
work and an impoundment field checklist was developed and adhered to 
during the assessment.
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    \8\ The results of this effort are either presented on a 
facility by facility basis or are summarized by round. All of these 
data have been posted on the Agency Web site.
---------------------------------------------------------------------------

    To ensure objectivity, EPA contracted with professional engineers 
(PEs) in the state where the impoundment was located who were experts 
in the area of dam safety to perform the site assessments. Each 
individual assessment was performed by PEs qualified in the areas of 
geotechnical engineering, hydrology and hydraulics, and overall dam 
safety. Upon evaluation of a robust set of technical documents 
addressing dam safety and inspections as well as comprehensive 
discussions with key dam safety organizations, the Assessment Program 
developed a comprehensive set of factors that were to be used to 
evaluate the overall safety of CCR surface impoundments, which 
concluded that, among other important factors, the static and seismic 
factors of safety, hydrologic and hydraulic capacity, liquefaction 
potential analysis and a post-liquefaction stability analysis if the 
soils of the embankment were identified to be susceptible to 
liquefaction, and operation and maintenance protocols, e.g. 
instrumentation monitoring, inspection program, emergency response 
protocols were critical parameters for assessing the overall safety of 
CCR surface impoundments.
    The individual evaluations or assessments were conducted at each 
impoundment at each facility using standard, accepted engineering 
practices, including a visual assessment of the CCR surface 
impoundment, interviews with site personnel, a review of the history of 
the CCR surface impoundment, and a review of engineering documentation 
related to the design, construction, operation, and maintenance of the 
impoundments, including available technical analyses. At each site 
visit, additional documentation was collected and reviewed as 
available, including descriptions, along with supporting information, 
of: (1) The impoundment, including location, size, age, design and/or 
alterations to the design, and the amount of residuals currently in the 
unit; (2) known, measured settlement of the impoundment embankment; (3) 
known, measured movement of the impoundment embankment; (4) observed 
erosion of the impoundment embankment; (5) seepage; (6) leakage; (7); 
observed cracking of the impoundment embankment; (8) deterioration, 
such as scarps, boils, or sloughs, of the -- embankment; (9); 
seismicity; (10) internal stresses; (11) functioning of foundation 
drains and relief wells; (12) stability of critical slopes adjacent to 
the units; and (13) regional and site geological conditions. If 
available, state and federal inspections reports were also reviewed.\9\
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    \9\ It is important to note that during the assessment, no 
physical drilling, coring or sampling was conducted, while on site; 
however, studies were reviewed that often included such information.
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    In addition, for each assessment, the following factors were 
identified, to the extent feasible, for evaluation: (1) The presence 
and adequacy of spillways; (2) hydrologic and hydraulic capacity of the 
unit; (3) overall structural adequacy and stability of structures under 
all credible loading conditions through a review of static, seismic, 
and liquefaction analyses with determined factors of safety; (4) soil, 
groundwater, surface water, geology, and geohydrology characteristics 
associated with the unit, including hydrological data accumulated since 
the impoundment was constructed or last inspected; (5) a history of the 
performance of the management unit through analysis of data from 
monitoring instruments, interviews with facility personnel, and review 
of available operating records; (6) quality and adequacy of 
maintenance, surveillance, and methods of unit operations for the 
protection of public safety; (7) location of schools, hospitals, or 
other critical infrastructures within five miles down gradient of the 
impoundment; and (8) whether the impoundment is located within 
federally designated flood plains. Finally, each impoundment and any 
associated spillways were evaluated to determine whether the 
impoundment and the spillways could withstand the loading or 
overtopping from appropriate inflow design flood events.
    Each CCR surface impoundment was classified with a hazard potential 
classification following the New Jersey Department of Environmental 
Protection

[[Page 21315]]

Bureau of Dam Safety and Flood Control's hazard potential ranking. Each 
impoundment was classified with a hazard potential classification of 
either; ``high,'' ``significant,'' ``low,'' or ``less-than-low.'' The 
hazard potential classification was a qualitative assessment of the 
potential adverse incremental consequences of a dam failure.
    At the conclusion of each assessment, a report was generated and 
the impoundment was given a condition rating of either; satisfactory, 
fair, poor, or unsatisfactory. The condition ratings were based on the 
availability of information on the unit and evaluation of the 
previously mentioned factors, including the static, seismic, and 
liquefaction factors of safety. No impoundments received an 
``unsatisfactory'' rating. Numerous impoundments were, however, rated 
as ``poor,'' often for lack of appropriate technical documentation in 
the aforementioned areas. ``Poor'' or ``fair'' ratings were also an 
indication that additional measures were needed to improve the 
stability of the unit. Of 559 impoundments assessed, 241 received a 
condition rating of ``satisfactory,'' 166 received a condition rating 
of ``fair,'' and 152 received a ``poor'' condition rating.
    It is important to note that the condition rating did not 
necessarily imply that the unit had inadequate structural integrity. On 
the contrary, in many instances a structurally sound impoundment may 
have been given a condition rating or ``fair'' or ``poor'' based on 
other factors such as a lack of documented information on the unit or 
insufficient operations and maintenance protocols. For example, an 
impoundment could be rated as ``poor'' if it lacked the appropriate 
technical documentation and analyses regarding structural or hydrologic 
and hydraulic analyses. EPA rated numerous units as ``poor'' based 
primarily on unavailable technical analyses.
    Once the assessment was performed, a draft report was prepared. 
Draft reports were reviewed by the appropriate state agency, the 
utility, and by EPA.\10\ Once comments were received and incorporated, 
a final report was issued along with recommendations for additional 
actions to be taken by the facility (if needed). Facilities then 
developed action plans and schedules to implement the recommendations. 
EPA also informed facility owners and operators that in addition to 
implementing their action plans, they need to adopt an ongoing, routine 
program to assess each surface impoundment and to take necessary 
corrective measures to ensure the units' continued structural 
integrity.
---------------------------------------------------------------------------

    \10\ As noted many times in this document, states play a 
critical role in implementing and overseeing these units. To assist 
states in this effort, EPA has, in the majority of cases directly 
provided the states with all of the information from our 
assessments. The Assessment Program reports may be accessed at: 
http://www.epa.gov/wastes/nonhaz/industrial/special/fossil/surveys2/index.htm.
---------------------------------------------------------------------------

2. Assessment Program Findings
    Upon completion of the Assessment Program, a review was undertaken 
to ascertain the key findings or lessons learned from the effort. These 
key findings included: (1) The majority of CCR surface impoundments are 
currently inspected on a periodic basis; (2) most utilities were 
readily able to supplement outdated or missing information with new or 
updated evaluations of their impoundments after the on-site portion of 
EPA's assessment was conducted; (3) in response to the assessment 
report recommendations, facilities typically willingly conducted 
remedial actions; (4) interaction with the states and the utilities 
assured accuracy in the final assessment reports; (5) placing site 
assessment materials on an internet site assured that the public, 
states, and utilities had full access to information about the design 
and operation of CCR impoundments and did not present either homeland 
security or other confidentiality concerns; (6) static, seismic, and 
liquefaction analyses did not pose a significant technical or cost 
burden on facilities since many already routinely conducted these types 
of evaluations; (7) state regulatory bodies viewed the assessments as a 
means to further support existing assessment programs; and (8) the use 
of PEs to certify all final reports ensured that the assessments 
reflected the PE's best judgments.
3. Assessment Program's Support for the Structural Integrity 
Requirements of the Rule
    As noted, the findings from EPA's Assessment Program provide 
technical and factual support for many of the final requirements for 
structural stability in this rule. A more detailed discussion of 
several of the most significant of these is presented below. Additional 
discussion of the relevance of these findings is included throughout 
Unit VI of this document.

a. Periodic Inspections/Assessments

    Consistent with the findings from the assessments and with EPA's 
recommendations to facilities as part of the Assessment Program, this 
rule requires that all CCR surface impoundments be inspected at 
intervals not exceeding seven days for any appearances of actual or 
potential structural weakness and other conditions that are disrupting 
or have the potential to disrupt the operation or safety of the CCR 
surface impoundment. Monitoring of instrumentation is also required to 
be conducted at intervals not exceeding 30 days. The Assessment Program 
found that virtually all utility companies conduct some sort of 
periodic inspection or monitoring at CCR surface impoundments, although 
practices varied among facilities and between states. The Assessment 
Program also found that while many facilities were conducting regularly 
scheduled inspections, some did not adequately document the results of 
these inspections.
    In the final rule, CCR surface impoundments exceeding a specified 
size threshold, i.e., height of five feet or more and capacity of 20 
acre-feet or more or a height of 20 feet or more, are required to 
perform annual inspections as well as two assessments of structural 
stability quinquennially, (i.e., every five years) that include a 
structural stability assessment of specified parameters and a factor of 
safety assessment. Annual inspections are broader in scope than weekly 
inspections and are conducted to ensure that the design, construction, 
operation and maintenance of the CCR unit is consistent with recognized 
and generally accepted good engineering standards. Annual inspections 
must include a review of available information regarding the status and 
condition of the unit and a visual inspection to identify signs of 
distress or malfunction of the unit and appurtenant structures. The 
annual inspections must be conducted by a qualified professional 
engineer.
    The Assessment Program also reviewed how detailed structural 
stability reviews and inspections were recommended to be conducted by 
FEMA, MSHA, and the USACE guidelines and found that such inspections 
were recommended to take place every three to five years. Review of 
state dam safety programs demonstrated that similar detailed 
inspections were also conducted on a three-to-five year cycle. 
Therefore, in the final rule, EPA is requiring that structural 
integrity assessments, including the calculation of factors of safety 
under various loading conditions, be conducted within 18 months of 
publication of the rule, and be repeated every five years. The five 
year review timeframe is based on documentation showing that the 
factual bases for such reviews are only sound for that time

[[Page 21316]]

period, and is consistent with federal dam safety guidance, 
specifically FEMA. FEMA recommends in Federal Guidelines for Dam Safety 
that dams be formally assessed at a frequency not to exceed five years 
by a qualified professional engineer. EPA has adopted this timeframe to 
maintain consistency with FEMA guidance. The inspection and assessment 
requirements in this rule will ensure that there are consistent and 
uniform inspection and assessment practices across states and 
facilities and will ensure that problems related to their stability 
will be promptly identified and remediated as necessary.

b. Static, Seismic, and Liquefaction Factors of Safety

    (1) Static Factors of Safety.
    Factor of safety (FOS) means the ratio of the forces tending to 
resist the failure of a structure, as compared to the forces tending to 
cause such failure as determined by accepted engineering practice. This 
analysis is used to determine whether a CCR surface impoundment's dikes 
are engineered to withstand the specific loading conditions that can be 
reasonably anticipated to occur during the lifetime of the unit without 
failure of the dike, if accepted good engineering practices are 
employed. Static factors of safety refer to the factors of safety (FOS) 
under static loading conditions that can reasonably be anticipated to 
occur during the lifetime of the unit. Static loading conditions are 
unique from other loading conditions (e.g., seismic, liquefaction) in 
that static loading conditions are those which are in equilibrium, 
meaning the load is at rest or is applied with constant velocity.
    EPA reviewed a series of USACE guidance documents addressing how to 
determine static FOS. These documents included, but were not limited 
to, Engineer Manual EM 1110-2-1902 ``Slope Stability'' (October 2003), 
and EM 1110-2-1902 ``Stability of Earth and Rock-Fill Dams.'' The 
Agency also assessed the recommendations on how to conduct static 
analysis contained in the Engineering and Design Manual for Coal Refuse 
Disposal Facilities, originally published by the Mining Enforcement and 
Safety Administration (MESA) in 1975 and updated for MSHA in May 2009, 
and in particular Chapter 6, ``Geotechnical Exploration, Material 
Testing, Engineering Analysis and Design.'' Based on recommendations 
from ASDSO, among others, the Agency adopted the USACE guidance to 
determine static FOS, both in the Assessment Program and in this 
rulemaking, as these manuals are recognized throughout industry as the 
standard routinely used in field assessment of structural integrity.
    In EPA's Assessment Program all CCR units were assessed to 
determine their static FOS. Each assessment classified a CCR unit as 
having sufficient structural stability under static loading conditions 
if analysis of critical sections of embankments demonstrated FOS that 
met or exceeded the values defined by USACE for static specific loading 
conditions. EPA found that most CCR surface impoundments exhibited 
sufficient calculated factors of safety under static loading 
conditions. EPA also found that in those CCR units which insufficient 
factors of safety against failure due to static loading were 
calculated, the owner or operator was able to implement actions which 
increased the factors of safety under static loading conditions to 
acceptable levels. Oftentimes, these implemented actions were of a 
simple nature, such as installing riprap (rock armoring the slopes) or 
buttressing the slopes.
    Similarly, this rule adopts the static FOS from USACE Engineer 
Manual EM 1110-2-1902 ``Slope Stability,'' with the exception of the 
rapid drawdown loading condition,\11\ which was determined not to be 
relevant to CCR surface impoundments. EPA found the factors of safety 
identified by EM 1110-2-1902, specifically the Maximum Storage pool, 
Maximum Surcharge pool, and End-Of-Construction loading conditions, 
provided consistent, achievable levels of safety in CCR surface 
impoundment dikes, comprehensively assessed static stability, and 
provided sufficient consideration of compounding stresses on dikes 
(e.g., factors of safety values greater than 1.00 to account for 
unanticipated loadings acting in conjunction or misidentified strength 
of materials).
---------------------------------------------------------------------------

    \11\ Rapid (or sudden) drawdown is a condition in earthen dikes 
that may develop when the embankment becomes saturated through 
seepage during a high pool elevation in the reservoir. Rapid 
drawdown becomes a threat to the dike when the reservoir pool is 
drawn down or lowered at a rate significantly higher than the excess 
poor water pressure within the dike can dissipate. Typically, rapid 
drawdown scenarios are considered for dikes with reservoirs used for 
water supply and management or agricultural supply. In these 
scenarios, a high pool elevation is maintained in the reservoir in 
storage months. Subsequently, the water supply is drawn on in months 
where there is a demand for the reservoirs contents. This drawing 
down of the pool can present issues for the structural integrity of 
the unit. However, the management of CCR surface impoundments 
differs from that of conventional water supply reservoirs. CCR 
surface impoundments are never used for water supply, and the only 
instance in which EPA determined through its Assessment Program that 
rapid drawdown loading conditions would be relevant to CCR surface 
impoundments was in the event that the CCR surface impoundment had 
already released the contents of the impoundment through a breach of 
the dike or emergency discharge. Since the threat of release of CCR 
and the reservoir has already been realized, any failure due to 
rapid drawdown of the embankment is no longer critical to the 
overall containment of the now-released contents of the CCR unit.
---------------------------------------------------------------------------

    (2) Seismic Factor of Safety.
    Seismic FOS means the FOS determined using analysis under 
earthquake conditions for a seismic loading event, based on the U.S. 
Geological Survey (USGS) seismic hazard maps for seismic events with a 
specified return period for the location where the CCR surface 
impoundment is located. The seismic FOS analysis is used to determine 
whether a dam would remain stable during an earthquake or other seismic 
event. The Agency relied on guidance from USACE and MSHA to evaluate 
the appropriate methods to determine if a dam would remain stable 
during a seismic event. This includes the USACE guidance Engineer 
Circular 1110-2-6061: Safety of Dams--Policy and Procedures 2204, 
Engineer Circular 1110-2-6000: Selection of Design Earthquakes and 
Associated Ground Motions 2008, and Engineer Circular 1110-2-6001: 
Dynamic Stability of Embankment Dams 2004). EPA also reviewed MSHA's 
2009 Engineering and Design Manual for Coal Refuse Disposal Facilities, 
in particular Chapter 7, ``Seismic Design: Stability and Deformation 
Analyses.'' These documents are viewed by ASDSO, FEMA and MSHA as 
generally accepted guidance on how to conduct seismic stability 
analyses.
    As noted earlier, in performing the assessments, EPA directed its 
engineering contractors to assess seismic stability of CCR impoundments 
during and following a seismic event with a 2% probability of 
exceedance in 50 years (i.e. probable earthquake within approximately 
2,500 years) and a horizontal spectral response acceleration for 1.0-
second period (5% of Critical Damping). EPA selected this return period 
for determining the maximum design earthquake (MDE) by first 
considering the operating life anticipated for CCR surface 
impoundments. EPA has identified the operating life of CCR surface 
impoundments to range between 40-80 years. EPA then consulted the 
United States Geological Survey (USGS) and ASDSO to determine a 
conservative probability that should be used in the assessments.\12\ To 
reduce the likelihood of a CCR unit failing during a seismic

[[Page 21317]]

event, the Agency assessed various return periods and chose a 
conservative 2500 year return period. The use of this ``return'' period 
was chosen because it is conservative, reflects the fact that many CCR 
impoundments are located in active seismic zones, and the use of a 
conservative ``return'' period ensures that if a unit meets the seismic 
FOS it is unlikely to fail under most seismic events. By evaluating 
seismic stability under a conservative return period and requiring the 
unit to maintain structural stability under that design seismic event, 
the likelihood of a seismic event occurring at the location of the CCR 
surface impoundment in which the strength of the unit is exceeded and 
the unit fails is considerably reduced. Additionally, the unit can 
reasonably be anticipated to withstand seismic events of a more 
frequent return period (i.e., smaller magnitude).
---------------------------------------------------------------------------

    \12\ Wieland, M., ``Seismic Design and Performance Criteria for 
Large Storage Dams'', Proc. 15th World Conf. on Earthquake 
Engineering, Lisbon, Portugal, Sep. 24-28, 2012.
---------------------------------------------------------------------------

    The Agency assessed CCR impoundments and classified them as having 
seismic stability if modeling results of critical failure surfaces were 
calculated to have a FOS greater than 1.0 under the specified seismic 
loading condition. The Assessment Program found that most CCR 
impoundments did meet the required seismic FOS. This rule also adopts 
this seismic stability FOS under the 2% probability of exceedance in 50 
years event.
    The Assessment Program found that many CCR impoundments had not 
undergone static or seismic analyses in sufficient detail that an 
independent professional engineer could assert that they were stable. 
The assessments gave impoundments a condition rating of ``poor'' if the 
utility was unable to provide static and seismic studies of their units 
conducted in a fashion which represented acceptable professional 
engineering practice. As the Assessment Program advanced, many 
utilities independently conducted new or updated static and seismic 
analyses of CCR surface impoundments in anticipation of their 
facilities being assessed. By the end of the program, virtually all 
facilities had conducted or were in the process of conducting static 
and seismic analyses. While some utilities noted concern over the costs 
of conducting additional static or seismic stability studies, none 
found that completing these studies presented any significant 
engineering challenges.
(3) Liquefaction Factors of Safety
    Liquefaction FOS means the factor of safety determined using 
analysis under liquefaction conditions. Liquefaction is a phenomenon 
which typically occurs in loose, saturated or partially-saturated soils 
in which the effective stress of the soils reduces to zero, 
corresponding to a total loss of shear strength of the soil. The most 
common occurrence of liquefaction is in loose soils, typically sands. 
The liquefaction FOS determination in the final rule is used to 
determine if a CCR unit would remain stable if the soils of the 
embankment of the CCR unit were to experience liquefaction. EPA relied 
primarily on one source to evaluate the appropriate methods to 
determine if a dam would remain stable under liquefaction conditions. 
This source was ``Soil Liquefaction during Earthquakes,'' Idriss and 
Boulanger, Earthquake Engineering Research Institute, 2008.\13\ EPA 
also reviewed several technical resources regarding soil liquefaction, 
including ``Ground Motions and Soil Liquefaction During Earthquakes,'' 
Seed and Idriss, 1982,\14\ ``Liquefaction Resistance of Soils: Summary 
report from the 1996 and 1998 NCEER/NSF Workshops on Evaluation of 
Liquefaction Resistance of Soils,'' Youd and Idriss, 2001,\15\ and 
Seismic Design Guidance for Municipal Solid Waste Landfill Facilities, 
US EPA, Office of Research and Development, 1995.\16\ These documents 
are viewed as generally accepted guidance on how to conduct 
liquefaction potential analyses and residual strength analyses under 
post-liquefaction conditions.
---------------------------------------------------------------------------

    \13\ https://www.eeri.org/products-page/monographs/soil-liquefaction-during-earthquakes-3/.
    \14\ Seed, H. B., and Idriss, I. M., 1982, ``Ground Motions and 
Soil Liquefaction During Earthquakes,'' Monograph No. 5, Earthquake 
Engineering Research Institute, Berkeley, California, pp. 134.
    \15\ Youd, T. L., Idriss, I. M., 2001, ``Liquefaction Resistance 
of Soils: Summary report from the 1996 and 1998 NCEER/NSF Workshops 
on Evaluation of Liquefaction Resistance of Soils.'' Journal of 
Geotechnical and Geoenvironmental Engineering, ASCE.
    \16\ United States EPA, Office of Research and Development, 
1995, EPA/600/R-95/051, RCRA Subtitle D (258) Seismic Design 
Guidance for Municipal Solid Waste Landfill Facilities. Available as 
of the Writing of this policy at www.epa.gov/clhtml/pubtitle.html on 
the U.S. EPA Web site.
---------------------------------------------------------------------------

    As noted earlier, in performing the assessments, EPA assessed the 
liquefaction potential of soils that compose the embankments of the CCR 
unit to determine if the soils present in the embankment were of the 
soil classification and configuration that was susceptible to 
liquefaction. This determination was based on evidence available 
through interviews with facility personnel, construction documentation, 
or representative soil sampling, such as information provided by 
corings and borings. Identical to the requirements for seismic factor 
of safety calculation, EPA selected a return period for a seismic event 
for analysis of liquefaction potential, under a seismic loading which 
may induce liquefaction in embankments, of a 2% probability of 
exceedance in 50 years. The discussion of the selection of this return 
period can be found in the ``Seismic Factor of Safety'' section above.
    The Agency assessed CCR impoundments and classified them as having 
stability under liquefaction conditions if representative soil 
sampling, anecdotal evidence from interviews with facility personnel, 
or construction documentation indicated that there was no 
susceptibility to liquefaction of the embankment soils or if modeling 
or analysis in critical failure planes in the embankment expected to be 
susceptible to liquefaction were calculated to have a FOS greater than 
1.00 under post-liquefaction conditions. The Assessment Program found 
that most CCR surface impoundments did not contain soils in detrimental 
volumes or configurations in the embankment that would indicate 
susceptibility to liquefaction. However, the assessment effort found 
that in embankments with a presence of soils susceptible to 
liquefaction, most CCR surface impoundments did not meet the required 
liquefaction FOS.
    The Assessment Program found that many CCR surface impoundments had 
not undergone liquefaction potential analyses or post-liquefaction 
residual strength analyses in those instances in which liquefaction 
potential was identified (i.e., soils subject to liquefaction were 
present). The assessments gave impoundments a condition rating of 
``poor'' if there was no information available to characterize the 
soils of the embankment, and a condition rating of ``poor'' or ``fair'' 
if post-liquefaction residual strength analysis of soils previously 
identified as being susceptible to liquefaction had not been available, 
with the rating dependent on the determined severity of the 
liquefaction potential in the embankment. Impoundments with calculated 
liquefaction factors of safety which did not meet or exceed 1.00 were 
given a condition rating of ``poor.''
    As the Assessment Program advanced, many utilities independently 
conducted new or updated liquefaction potential analyses or residual 
strength analyses of CCR surface impoundments in anticipation of their 
facilities being assessed. By the end of the program, virtually all 
facilities had conducted or were in the process of conducting 
liquefaction potential analyses or residual strength analyses. While 
some utilities noted concern over the costs of

[[Page 21318]]

conducting additional liquefaction potential or residual strength 
studies, none found that completing these studies presented any 
significant engineering challenges.
    Based on its experience in the Assessment Program and subsequent 
review of numerous technical resources, EPA determined that a post-
liquefaction residual strength factor of safety in the embankment of 
1.00 is not sufficient. Liquefaction potential analysis and post-
liquefaction residual strength analysis involves a larger degree of 
uncertainties, e.g., liquefiable stratum configuration, in assumptions 
and analysis which must be accounted for with a factor of safety above 
1.00. The final rule therefore requires CCR surface impoundments which 
are constructed of soils determined to be susceptible to liquefaction 
to meet or exceed a liquefaction factor of safety of 1.20. EPA has 
determined that 1.20 is an appropriate liquefaction factor of safety 
based on several technical guidances and memos, including Federal 
Guidelines for Dam Safety: Earthquake Analyses and Design of Dams, 
Document 65, FEMA May 2005, which states that ``post-liquefaction 
factors of safety are generally required to be a minimum of 1.2 to 
1.3.'' 17 18 19 20 21
---------------------------------------------------------------------------

    \17\ US Bureau of Reclamation (USBR), ``Water Operation and 
Maintenance Bulletin No. 222,'' Denver, Colorado, December 2007.
    \18\ http://www.oregon.gov/odot/hwy/bridge/docs/bddm/pdfs/psha.pdf.
    \19\ Canadian Dam Association. Canadian Dam Safety Guidelines, 
2007, 88 pp.
    \20\ Sonmez, H., 2003. Modification of the liquefaction 
potential index and liquefaction susceptibility mapping for a 
liquefaction-prone area (Inegol, Turkey), Env. Geology, (44): 862-
871.
    \21\ Seed, R.B., Cetin, O.K., Moss, R.E.S., Kammerer, A.M., Wu, 
J., Pestana, J.M., Riemer, M.F., Sancio, R.B., Bray, J.D., Kayen, 
R.E., Faris, A., 2003. Recent advances in soil liquefaction 
engineering: a unified and consistent framework, 26th annual ASCE 
L.A. Geot. Spring Sem., Long Beach, California, April 30, 71 pp.
---------------------------------------------------------------------------

c. Impoundment Height and Relationship to Regulatory Requirements

    During the Assessment Program, the Agency reviewed the stability 
issues related to various heights of impoundments. The Assessment 
Program concluded that impoundments with heights less than five feet or 
those retaining less than 20 acre feet were unlikely to cause 
significant environmental or economic loss should they undergo a 
catastrophic failure. The Agency's review of MSHA and FEMA guidance 
also noted that ``small'' units were unlikely to cause significant 
losses should they fail. Based on the Agency's experience and FEMA and 
MSHA's guidance, the Agency has concluded that there is a substantial 
benefit in having impoundments which exceed a specified size threshold, 
i.e., height of five feet or more and capacity of 20 acre-feet or more 
or a height of 20 feet or more determine their static, seismic, and 
liquefaction FOS on a regular basis. The analyses and experience gained 
in conducting the Assessment Program indicates that a catastrophic 
failure of a CCR surface impoundment is unlikely to occur so long as 
the factors of safety are maintained or exceeded throughout the unit's 
operating life. This conclusion is also consistent with relevant 
guidance and regulations which do not require such evaluations for 
units below a certain size threshold.

d. Hazard Potential Ratings

    Each impoundment assessed in the Assessment Program was given a 
Hazard Potential Classification rating of either Less-than-Low, Low, 
Significant, and High. Previous classifications were reviewed and 
amended as necessary to reflect guidance developed for the Assessment 
Program. The hazard potential ratings refer to the potential for loss 
of life or damage if there is a dam failure. The ratings do not refer 
to the condition or structural stability of the dam. Four hazard 
potential classifications were used in assessing the impoundments in 
the Assessment Program:
    High Hazard Potential--Dams assigned the high hazard potential 
classification are those where failure or mis-operation will probably 
cause loss of human life.
    Significant Hazard Potential--Dams assigned the significant hazard 
potential classification are those dams where failure or mis-operation 
results in no probable loss of human life, but can cause economic loss, 
environment damage, disruption of lifeline facilities, or impact other 
concerns. Significant hazard potential classification dams are often 
located in predominantly rural or agricultural areas, but could be 
located in areas with population and significant infrastructure.
    Low Hazard Potential--Dams assigned the low hazard potential 
classification are those 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 owner's property.
    Less Than Low Hazard Potential--Dams which do not pose high, 
significant, or low hazard potential.
    There is a substantial benefit in having owners or operators of all 
CCR impoundments determine the hazard potential classification of their 
units. The Assessment Program found that many CCR surface impoundments 
had not been given a hazard potential classification and consequently, 
their potential threat to human health and the environment if a failure 
were to occur was not clearly identified, nor had response plans been 
developed to respond to any catastrophic failure. Moreover, these 
classifications should be updated over time, particularly to account 
for changes such as population growth, construction of key 
infrastructure, or changes to the impoundment's size or operation. The 
Assessment Program also found that some states do not classify CCR 
impoundments as ``dams'' and therefore those units may not be required 
to determine their hazard potential classification or otherwise 
evaluate the potential effects of a catastrophic failure. Consistent 
with the guidance from ASDSO, FEMA, and the state of New Jersey, this 
rule requires that all diked CCR impoundments determine their hazard 
potential classification according to the definitions set out in this 
regulation. For those units with a hazard potential classification of 
significant or high, the owner or operator of such impoundments is also 
required to develop an Emergency Action Plan to address the higher 
potential impacts of a potential failure.

e. Condition Ratings

    While the rule does require facilities to evaluate the same 
engineering factors that went into developing these ratings, the rule 
does not require that each impoundment be given a condition rating. 
After evaluation of the use of these ratings, the Agency determined 
that the rating may have relied too heavily on subjective factors. For 
that reason, this rule requires that the qualified professional 
engineer certify, based on quantitative determinations, that an 
impoundment meets the requirements for FOS and hydraulic and hydrologic 
capacity. This approach is less subjective and allows the professional 
engineer to make quantifiable certifications.

IV. Bevill Regulatory Determination Relating to CCR From Electric 
Utilities and Independent Power Producers

    As discussed in the preceding sections, in the proposed rule EPA 
reopened its August 1993 and May 2000 Regulatory Determinations 
regarding CCR generated at electric utilities and independent power 
producers, to re-evaluate whether regulation of CCR under RCRA subtitle 
C is necessary in light of subsequent information. EPA explained that 
this was based on several

[[Page 21319]]

relatively recent developments, such as a newly completed quantitative 
risk assessment that concluded that the disposal of CCR in unlined 
waste management units posed substantial risks, with upper end risk 
estimates ranging from 10-2-10-4. Citing to the 
recent structural failures of surface impoundments, the proposed rule 
also noted that these wastes have caused greater damage to human health 
and the environment than EPA originally estimated. Finally, EPA 
explained that recently collected information regarding the existing 
state regulatory programs had called into question whether those 
programs, in the absence of national minimum standards specific to 
these wastes, had sufficiently improved to address the gaps originally 
identified in the May 2000 Regulatory Determination. EPA ultimately 
concluded that federal regulation of this material was necessary, but 
did not reach any conclusion as to whether regulation under subtitle D 
would be sufficient or whether regulation under subtitle C would be 
necessary to adequately address the risks.
    Of the over 450,000 comments received on the proposed rule, the 
vast majority focused on whether the Bevill exemption should be 
retained, and the corresponding question of whether CCR regulations 
should be established under RCRA subtitle C or subtitle D. In terms of 
the sheer numbers, the majority of commenters supported a decision to 
revoke the Bevill exemption and to regulate CCR under a subtitle C 
rule. These commenters, largely individual members of the public and 
environmental groups, generally argued that the Bevill exemption should 
be revoked because state programs have failed to adequately regulate 
the disposal of CCR and because the risks associated with the 
management of these wastes are significant. In support of both points, 
these commenters pointed to the fact that the number of damage cases 
that have been discovered has increased substantially since the 
original 2000 Regulatory Determination, and have continued to grow 
since publication of the proposed rule in 2010.
    By contrast, state organizations, individual states, and industry 
groups (electric utilities, recycling firms, trade associations), 
largely favored a subtitle D rule. Overall, these commenters raised 
concern about the costs of the subtitle C regime, arguing that the 
subtitle C requirements were more stringent than necessary to address 
the risks from CCR disposal. Commenters also raised concern that 
regulation of these wastes under subtitle C would negatively affect the 
beneficial use of these materials, arguing that the stigma associated 
with regulating the disposal of CCR as a hazardous waste would 
``cripple'' the current beneficial reuse market. Many of these 
commenters also argued that EPA lacks the legal authority to regulate 
these wastes under subtitle C on a variety of grounds, including claims 
that EPA entirely lacks the authority to revisit its Bevill Regulatory 
Determination, and that EPA had failed to comply with statutory 
procedures in doing so.

A. Deferral of a Final Decision on the Bevill Regulatory Determination 
for CCR Destined for Disposal

    In determining whether the Bevill exemption should be retained for 
CCR, EPA must evaluate and weigh eight factors that were enumerated in 
section 8002(n) of RCRA. 42 U.S.C. 6921(b)(3)(C). The eight factors 
are: (1) The source and volumes of CCR generated per year; (2) present 
disposal and utilization practices; (3) potential danger, if any, to 
human health or the environment from the disposal and reuse of CCR; (4) 
documented cases in which danger to human health or the environment 
from surface run-off or leachate has been proved; (5) alternatives to 
current disposal methods; (6) the cost of such alternative disposal 
methods; (7) the impact of those alternatives on the use of coal and 
other natural resources; and (8) the current and potential utilization 
of CCR. 42 U.S.C. 6982(n).
    EPA addressed each of these study factors in the 1988 and 1999 
Reports to Congress, and in reaching our decisions in the August 1993 
and the May 2000 Regulatory Determinations to maintain the Bevill 
exemption for CCR. 58 FR 42466 (August 9, 1993); 65 FR 32214 (May 22, 
2000). Consequently, in considering whether to reverse these Regulatory 
Determinations for CCR destined for disposal, EPA reexamined the RCRA 
section 8002(n) study factors against all of the available data, which 
included both the data that formed the basis for the May 2000 
Regulatory Determination and the most recent data available. (See 75 FR 
35150-35156.)
    As discussed at length in the proposed rule, three of these factors 
weighed the most heavily in the Agency's decision to reconsider its 
previous Regulatory Determinations. (See 75 FR 35133 and 35156-35158.) 
The first of these related to the extent of the risks posed by the 
current management of these wastes. Since the 2000 Regulatory 
Determination, EPA had completed a quantitative risk assessment that 
estimated significant risks to human health and the environment. EPA's 
2010 CCR risk assessment estimated the cancer risk from arsenic that 
leaches into groundwater from CCR managed in units without composite 
liners to exceed EPA's typical risk thresholds of 10-4 to 
10-6. For example, depending on various assumptions about 
disposal practices (e.g., whether CCR is co-disposed with coal refuse), 
groundwater interception and arsenic speciation, the 90th percentile 
risks from unlined surface impoundments ranged from 2 x 10-3 
to 1 x 10-4. The risks from clay lined surface impoundments 
ranged from 7 x 10-2 to 4 x 10-5. Similarly, 
estimated risks from unlined landfills ranged from 5 x 10-4 
to 3 x 10-6, and from 2 x 10-4 to 5 x 
10-9 for clay-lined landfills. EPA's risk assessment also 
estimated Hazard Quotients (HQs) \22\ above 1 for other metals, 
including selenium and lead in unlined and clay-lined units. However, a 
number of technical questions were raised regarding this quantitative 
risk assessment that called into question the accuracy of these risk 
estimates.
---------------------------------------------------------------------------

    \22\ For more information on HQs please see Unit X. Risk 
Assessment of this preamble.
---------------------------------------------------------------------------

    A second and equally significant consideration related to how 
effectively state regulatory programs address the risks associated with 
the improper management of these wastes. The existing reports on state 
regulatory programs had called into question whether the trend in 
improving state regulatory regimes that EPA identified in May 2000 had 
materialized to the degree anticipated in the Regulatory Determination. 
EPA noted concern about the lack of substantial details regarding the 
full extent of state regulatory authority over the disposal of these 
materials, and the manner in which states have, in practice, 
implemented this oversight.
    The final consideration, which is tightly related to the first two, 
was the recent information documenting continued instances involving 
the contamination of ground or surface water from the management of 
these wastes. Since the 2000 Regulatory Determination EPA had gathered 
or received information on 67 ``proven or potential'' cases involving 
damage to (i.e., contamination of) ground and surface water, and to 
human health and the environment from improper management of CCR in 
landfills and surface impoundments. These also included cases involving 
the structural failure of surface impoundments and the catastrophic 
release of CCR.

[[Page 21320]]

    For each of these key areas, EPA identified a number of issues on 
which the absence of critical information prevented the Agency from 
reaching an initial decision on whether to revise the Bevill 
Determination. Some of these issues or uncertainties have been resolved 
during the development of the final rule, either as a result of 
information received from commenters or through additional information 
and analyses EPA obtained or developed, which were held out for comment 
in subsequent NODAs. See 75 FR 35128 (October 21, 2010) and 78 FR 46940 
(August 2, 2013). However, as discussed in more detail below, critical 
information necessary to make a final Regulatory Determination is still 
lacking in two of these three areas. This information bears directly on 
the extent and magnitude of the risks over the course of the next 
several years, and the degree to which those risks can be managed 
sufficiently under each of the two regulatory structures available to 
the Agency. In the absence of this information, EPA is unable to reach 
a conclusion on the issue that is central to a Bevill Determination: 
Whether the risks presented by management of CCR waste streams can only 
be adequately mitigated through regulation under RCRA subtitle C. As a 
consequence, EPA is deferring a final Regulatory Determination for 
these wastes.\23\
---------------------------------------------------------------------------

    \23\ Because EPA is deferring its final Bevill Determination, 
EPA has not responded to comments that pertain exclusively to that 
issue. However EPA has responded to significant comments that relate 
to topics that are otherwise relevant to the final subtitle D 
regulation. For example, because EPA is relying on the damage cases 
to support certain aspects of the technical requirements, EPA has 
responded to comments relating to the accuracy of the facts involved 
in the damage cases. EPA has not, however, responded to many 
comments on state programs because the Agency has made no final 
conclusions on the adequacy of those programs and is not relying on 
state programs to support any of the final rule's provisions.
---------------------------------------------------------------------------

    Nevertheless, the record is clear that current management of these 
wastes can present, and in many cases has presented, significant risks 
to human health and the environment. Although EPA cannot reach 
conclusions as to the full extent or magnitude of those risks over the 
long term, the current level of risk clearly warrants the issuance of 
federal standards to ensure consistent management practices and a 
national minimum level of safety.
    In the following sections, EPA describes the information that was 
obtained over the course of the rulemaking relating to each area of 
concern, and the extent to which the new information addressed the 
issue.
1. Risks Posed by Current Management of CCR and Potential Danger to 
Human Health From the Disposal of CCR
    In the proposed rule, EPA specifically noted that several 
uncertainties remained in the Agency's quantitative risk analysis of 
the current management of CCR. Chief among these uncertainties was the 
evolving character and composition of CCR due to electric utility 
upgrades and retrofits of multi-pollutant controls needed to comply 
with the emerging Clean Air Act (CAA) requirements, which could present 
new or otherwise unforeseen contaminant issues (e.g., addition of 
calcium bromide to coal prior to combustion increasing mercury capture; 
use of selective catalytic reduction for post-NOX controls 
forming hexavalent chromium). As EPA explained, changes to fly ash and 
other types of CCR is expected to occur as a result of increased use 
and application of advanced air pollution control technologies in coal-
fired power plants. These technologies include flue gas desulfurization 
(FGD) systems for SO2 control, selective catalytic reduction 
(SCR) systems for NOX control, and activated carbon 
injection (ACI) systems for mercury control. These technologies are 
being installed or are expected to be installed in response to federal 
regulations, state regulations, legal consent decrees, and voluntary 
actions taken by industry to adopt more stringent air pollution 
controls. Use of these more advanced air pollution control technologies 
reduces air emissions of metals and other pollutants in the flue gas of 
a coal-fired power plant by capturing and transferring the pollutants 
to the fly ash and other air pollution control residues. Previous EPA 
studies of whether increased pollutant content would increase the risks 
correspondingly were inconclusive. For example, EPA evaluated the 
environmental fate of metals that are captured in CCR through use of 
enhanced air pollution controls, by characterizing the leaching 
behavior of 73 air pollution control residues, using the Leaching 
Environmental Assessment Framework (LEAF) methodology. Materials were 
tested over the pH conditions and liquid/solid ratios expected during 
management via land disposal or beneficial use. Leachate concentrations 
for most metals were highly variable over a range of coal type, 
facility configurations, and air pollution control residues. In 
addition, the data showed significantly different leaching behavior for 
similar residue types and facility configurations. Overall, the 
variability in leaching of the metals in the CCR was greater than the 
variability in totals concentrations by several orders of magnitude, 
suggesting that total pollutant content may not be predictive of 
leaching behavior, and consequently the risks.\24\
---------------------------------------------------------------------------

    \24\ Thorneloe, S, Kosson, D., Sanchez, F., Garrabrants, A.C., 
and Helms, G., Evaluating the Fate of Metals in Air Pollution 
Control Residues from Coal-Fired Power Plants, Environ. Sci. 
Technol. 2010, 44, 7351-7356.
---------------------------------------------------------------------------

    The Agency received no data from commenters that would aid in 
resolving this uncertainty. To try to establish some parameters around 
the uncertainty, EPA attempted to develop estimates of the extent to 
which this issue could meaningfully affect the risks.
    As an initial step, EPA focused on mercury pollution controls, as 
mercury levels in these wastes was an issue of particular concern in 
the public comments. It has been established that mercury pollution 
controls can affect both the mercury content and the general leaching 
behavior of ash (US EPA 2006, 2008, 2009). Using the limited data 
available, EPA attempted to evaluate the extent to which mercury 
controlled wastes could ultimately affect the overall risk associated 
with disposal of CCR.
    EPA conducted a sensitivity analysis that filtered the full 2014 
risk assessment results for the subset of fly ash samples generated by 
facilities that have currently installed ACI systems. The samples were 
collected from five different facilities that were either installing or 
evaluating an ACI system for increasing mercury capture. At each 
facility, samples were collected both before and after the installation 
of an ACI system. Ultimately the results were inconclusive, likely 
because of the small sample size, and EPA can draw no conclusions about 
the exact effects of ACI systems on the risks from CCR disposal. 
Nevertheless, the analysis provided some useful information. Capturing 
and transferring pollutants from air emission to the fly ash and other 
air pollution control residues would normally be expected to increase 
the risks associated with disposal of these wastes. EPA's analyses, 
however, showed only a marginal difference in risks for ash generated 
with or without the use of an ACI system, and in some instances the 
risks decreased slightly with the addition of activated carbon. The 
significance of these results should not be overstated--the observed 
decreases were not consistent and were thought to be an artifact of the 
relatively small number of model iterations. It is also important to 
remember that these results provide no information about the potential 
effects from the installation of

[[Page 21321]]

FGD systems for SO2 control, or SCR systems for 
NOX control, any of which could also significantly affect 
the characteristics of the wastes. But these results also suggest that 
EPA should be cautious about assuming that the risks will necessarily 
increase as a result of the imposition of additional air pollution 
controls.
    Other uncertainties in the risk assessment developed for the 
proposal related to the extent to which some sampled data with high 
concentrations of constituents used in the risk assessment accurately 
reflect coal ash leaching from landfills or surface impoundments. For 
example, as explained in the proposed rule, some data reflected pore 
water taken in the upper section of a surface impoundment where coal 
refuse was placed. There were acid generating conditions and high 
concentrations of arsenic, but the data demonstrated that the 
underlying coal ash neutralized the acid conditions and greatly reduced 
the arsenic which leached from the bottom of the impoundment. EPA also 
noted that much of the pore water samples and leachate data were 
several years old, and questions had been raised whether these data 
accurately reflected current management practices. Finally, EPA noted 
that recent research indicated that traditional leach procedures (e.g., 
Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic 
Precipitation Leaching Procedure (SPLP)) may underestimate the actual 
leach rates of toxic constituents from CCR under different field 
conditions.
    First, regarding the question of appropriate pH conditions in CCR 
units, and the resulting leachate concentrations in impoundments where 
coal refuse was placed, EPA obtained data during the development of 
this rule directly relevant to this issue. A survey conducted by the 
Electric Power Research Institute (EPRI) in 1995 had shown that 34 
percent of unlined landfills and 68 percent of unlined surface 
impoundments actively managed CCR with coal refuse. However, more 
recent data collected by EPA as part of the Clean Water Act ELG 
rulemaking in 2009-2010 indicates that this management practice has 
declined significantly to approximately five percent of current units.
    EPA also obtained sufficient data to resolve concerns about the 
accuracy of the concentrations in pore water and leachate used in the 
risk assessment. EPA received a substantial amount of data on CCR 
chemical constituents from commenters, which included total 
concentrations, pore water, and leaching test results for various types 
of CCR, i.e., bottom ash, FGD gypsum, FGD sludge, fly ash cenospheres, 
boiler slag, and combined waste streams. This included data from 
several EPRI reports, which provided field leachate results for bottom 
ash, fly ash, and FGD solids from a number of landfills and surface 
impoundments. EPA also received leachate data from the Alaska 
Department of Environmental Conservation, the Michigan Department of 
Natural Resources and Environment (MI DNRE), and from the Maryland 
Department of the Environment on total metals, TCLP, and SPLP results 
for bottom ash and fly ash. Included among these data were TCLP results 
for 102 CCR samples and 12 FGD gypsum samples, and two landfill 
leachate samples, as well as several laboratory reports on CCR leachate 
from 2008 through 2010. EPA also received several reports from the 
University of North Dakota Energy & Environmental Research Center, with 
leaching test results for 58 fly ash, five FGD, and four FGD gypsum 
samples using various leaching methods other than TCLP, and TCLP 
mercury results for 15 fly ash samples, as well as leaching test 
results for five fly ash and two bottom ash samples using 18-hr, 30-
day, and 60-day leach methods, plus bulk and trace element data for 
five fly ash samples, two bottom ash samples, and one slag sample. (See 
76 FR 63252, October 12, 2011.)
    In addition to the data submitted by commenters, EPA's Office of 
Research and Development (ORD), in collaboration with Vanderbilt 
University (VU), developed additional CCR leaching data using a revised 
methodology, the Leaching Environmental Assessment Framework, or LEAF, 
consisting of four methods that evaluate leaching potential for various 
waste forms at different plausible pH values and liquid-solid ratios, 
in order to more accurately simulate leaching potential over a variety 
of field conditions. The LEAF methods went through validation working 
with 20 different laboratories, different waste matrices, and 
documented in two EPA reports finding good agreement between the labs 
for the four methods.\25\ In addition, EPA compiled decades of data for 
ten different case studies to compare field and laboratory leach 
data.\26\ These data also showed LEAF methods to be a good predictor of 
field leachate behavior using geochemical speciation modeling for 
factors such as oxidation that are difficult to account for in the lab. 
When considered along with the methods validation, the field-to-lab 
leachate data comparison provides additional confidence that LEAF 
methods can more accurately predict environmental release over a range 
of materials, waste form, pH, liquid-solid ratio, and other parameters 
influencing leaching behavior such as calcium depletion for a material.
---------------------------------------------------------------------------

    \25\ Garrabrants A.C., D.S. Kosson, H.A. van der Sloot, F. 
Sanchez and O. Hjelmar (2010) Background information for the 
Leaching Environmental Assessment Framework (LEAF) Test Methods, 
EPA-600/R-10/170, U.S. Environmental Protection Agency, Air 
Pollution Prevention and Control Division, December 2010.
    Garrabrants A.C., D.S. Kosson, L. Stefanski, R. DeLapp, P.F.A.B. 
Seignette, H.A. van der Sloot, P. Kariher and M. Baldwin (2012a) 
Interlaboratory Validation of the Leaching Environmental Assessment 
Framework (LEAF) Method 1313 and Method 1316, EPA/600/R-12/623, U.S. 
Environmental Protection Agency, Air Pollution Prevention and 
Control Division, September 2012.
    Garrabrants A.C., D.S. Kosson, R. DeLapp, P. Kariher, P.F.A.B. 
Seignette, H.A. van der Sloot, L. Stefanski and M. Baldwin (2012b) 
Interlaboratory Validation of the Leaching Environmental Assessment 
Framework (LEAF) Method 1314 and Method 1315, EPA-600/R-12/624, U.S. 
Environmental Protection Agency, Air Pollution Prevention and 
Control Division, September 2012.
    \26\ Kosson D.S., van der Sloot, H.A., Seignette, P.F.A.B. 2014. 
Leaching Test Relationships, Laboratory-to-Field Comparisons and 
Recommendations for Leaching Evaluation using the Leaching 
Environmental Assessment Framework (LEAF), EPA-600/R-14/061. EPA 
Office of Research and Development, National Risk Management 
Research Laboratory, Research Triangle Park, NC, 27711. December.
---------------------------------------------------------------------------

    In updating the risk assessment for the final rule, EPA relied on 
surface impoundment pore water data and impoundment wastewater data, 
including the data submitted by commenters. For landfills, EPA only 
used LEAF data to characterize the leachate for the range of materials 
resulting from various air pollution control technologies. The CCR data 
documented in three EPA reports \27\ and summarized in Thorneloe et al, 
2010 \28\

[[Page 21322]]

provides a robust characterization of air pollution control residues 
from coal-fired power plants and indicates that leaching rates can vary 
by several orders of magnitude, depending on pH levels and the amount 
of liquid that comes into contact with the CCR solids (i.e., the liquid 
to solid ratio).
---------------------------------------------------------------------------

    \27\ Sanchez F., R. Keeney, D.S. Kosson and R. DeLapp (2006) 
Characterization of Mercury-Enriched Coal Combustion Residues from 
Electric Utilities using Enhanced Sorbents for Mercury Control, EPA-
600/R-06/008, U.S. Environmental Protection Agency, Air Pollution 
Prevention and Control Division, February 2006.
    Sanchez F., D.S. Kosson, R. Keeney, R. DeLapp, L. Turner and P. 
Kariher (2008) Characterization of Coal Combustion Residues from 
Electric Utilities using Wet Scrubbers for Multi-pollutant Control, 
EPA-600/R-08/077, U.S. Environmental Protection Agency, Air 
Pollution Prevention and Control Division, July 2008.
    Kosson D.S., F. Sanchez, P. Kariher, L.H. Turner, R. DeLapp, and 
P. Seignette (2009) Characterization of Coal Combustion Residues 
from Electric Utilities--Leaching and Characterization Data, EPA-
600/R-09/151, U.S. Environmental Protection Agency, Air Pollution 
Prevention and Control Division, December 2009.
    \28\ Thorneloe S.A., D.S. Kosson, F. Sanchez, A.C. Garrabrants 
and G. Helms (2010) ``Evaluating the fate of metals in air pollution 
control residues from coal-fired power plants,'' Environmental 
Science and Technology, 44, 7351-7356.
---------------------------------------------------------------------------

    The 2014 risk assessment incorporates these new data, and accounts 
for both the pH of the waste in field conditions, as well as the 
liquid-to-solid ratio of the leachate and CCR, which effectively 
addresses the concerns raised in the proposed rule that TCLP and SPLP 
methods could underestimate leachate concentrations.
    A further area of uncertainty related to one of the primary inputs 
into the risk assessment. As noted in the proposed rule, the Agency's 
risk estimates were based on the existing cancer slope factor of 1.5 
mg/kg/d-1 for arsenic in EPA's Integrated Risk Information 
System (IRIS). However, EPA noted that was in the process of 
revaluating the arsenic cancer slope factor in light of recent 
recommendations from the National Research Council (NRC) of the 
National Academy of Sciences (NAS) in ``Critical Aspects Arsenic in 
Drinking Water, 2001 Update.'' In the proposal, EPA estimated that 
using this NRC data analysis would increase the individual risk 
estimates by approximately 17 times.
    EPA is currently evaluating the arsenic cancer slope factor in 
light of more recent NRC recommendations, regarding the approach and 
the science for estimating cancer and non-cancer risk in ``Critical 
Aspects of EPA's IRIS Assessment of Inorganic Arsenic, (NRC 2013).'' 
EPA is in the process of implementing these recommendations, but to 
date has been unable to finalize its IRIS reassessment. Nor did EPA 
receive any other information during the development of this final rule 
that would help to resolve this uncertainty.
    A final source of uncertainty in the risk assessment developed for 
the proposed rule related to the potential impact from the interception 
of contaminated groundwater plumes by surface water bodies that exist 
between a waste management unit and a down-gradient drinking water 
well. It is common for coal-fired utilities to be located near water 
bodies, which are used as a source of cooling water and waste 
conveyancing. Releases from surface impoundments located in close 
proximity to water bodies can be intercepted, which can significantly 
affect the contaminants that reach drinking water wells. For example, 
surface impoundments are commonly placed next to rivers, which can 
intercept the leachate plume and prevent contamination of drinking 
water wells on the other side of the river. Also, in such circumstances 
the direction of groundwater flow on both sides of the river may be 
towards the river; thus, the drinking water well on the opposite side 
of a river may not be impacted.
    Over the course of the rulemaking, EPA was able to obtain 
sufficient data to model the impact from interception of contamination 
by surface water bodies. The risk assessment developed for the final 
rule accounts for the interception of the groundwater contamination 
plume by surface water bodies, and the resulting decrease in 
constituent mass to downstream drinking water sources. As a consequence 
of this modeling, the median risks for surface impoundments and 
landfills were substantially lower than both the high-end and median 
risks modeled in the 2010 risk assessment, i.e., by approximately an 
order of magnitude.
2. Adequacy of Existing State Regulatory Oversight
    The assessment of state regulatory programs in the proposed rule 
was based largely on two reports: A joint U.S. Department of Energy 
(DOE) and EPA study completed in 2006, ``Coal Combustion Waste 
Management at Landfills and Surface Impoundments, 1994-2004,'' and a 
2009 survey conducted by the Association of State and Territorial Solid 
Waste Management Officials (ASTSWMO). EPA's preliminary conclusion was 
that while states seem to be regulating landfills to a greater extent 
than in 2000, significant gaps in state programs appeared to remain, 
particularly with respect to the oversight of surface impoundments.
    In reaching this conclusion EPA noted the following findings from 
the DOE/EPA study: only 19 percent (three out of 19) of the surveyed 
surface impoundment permits included requirements addressing 
groundwater protection standards (i.e., contaminant concentrations that 
cannot be exceeded) or closure/post-closure care, and only 12 percent 
(two out of 12) of surveyed units were required to obtain bonding or 
financial assurance. The EPA/DOE report also concluded that 
approximately 30 percent of the net disposable CCR generated was 
potentially exempt from all state solid waste permitting requirements 
(EPA/DOE Report at pp 45-46). For example, at the time of the report, 
Alabama did not regulate CCR disposal under any state waste authority 
and nor had a dam safety program. Texas (the largest coal ash producer) 
did not require permits for waste managed on-site, which is defined as 
waste managed at any site owned by the generator, up to 50 miles away 
from the generating facility. Finally, the report found that a number 
of states only regulated surface impoundments under CWA authorities, 
and consequently primarily addressed the risks from effluent discharges 
to navigable waters, but did not require liners or groundwater 
monitoring.
    The more recent 2009 ASTSWMO survey reached similar conclusions. 
With respect to liner requirements, 36 percent of surveyed states did 
not have minimum liner requirements for CCR landfills, while 67 percent 
did not have CCR liner requirements for surface impoundments. 
Similarly, 19 percent of states surveyed did not have minimum 
groundwater monitoring requirements for landfills and 61percent did not 
have groundwater monitoring requirements for surface impoundments. The 
2009 ASTSWMO survey also indicated that only 36 percent of states 
regulated the structural stability of surface impoundments.
    In the proposal, EPA identified several issues that complicated its 
preliminary assessment and prevented the Agency from reaching overall 
conclusions as to the adequacy of state regulatory programs. First, EPA 
raised concern about the absence of any real details in the two reports 
regarding how states, in practice, oversee the disposal or other solid 
waste management of CCR. For example, even though the disposal units 
might not be regulated under the state solid waste provisions, some 
states may use performance based standards or implement requirements to 
control CCR landfills and surface impoundments under other state 
programs. Second, EPA noted that most of the more recent data primarily 
focused on the requirements applicable to new management units, which 
only represented approximately 10 percent of currently operating units. 
EPA had little, if any, information that described the extent to which 
states and utilities had implemented requirements, such as groundwater 
monitoring, on the many existing landfills and surface impoundments 
that receive CCR. Moreover, the information in the record for the 
proposal with respect to these older units was fifteen years old. EPA 
assumed it to be unlikely that states would have required existing 
units to install liners, but suggested states may have been more likely 
to have imposed groundwater monitoring for such units over the last 15 
years.

[[Page 21323]]

    EPA also identified several issues that would be relevant to the 
Agency's evaluation of the overall adequacy of state regulatory 
programs. Specifically, EPA explained that it would consider how state 
regulatory programs have, in practice, evaluated and imposed 
requirements to address: (1) Leachate collection; (2) groundwater 
monitoring; (3) whether a unit must be lined and the type of liner 
needed; (4) the effectiveness of existing management units as opposed 
to new management units; (5) whether the state requires routine 
analysis of CCR; (6) whether financial responsibility requirements are 
in place for the management of CCR; (7) the extent of permit 
requirements, including under what authorities these disposal units are 
permitted, the types of controls that are included in permits, and the 
extent of oversight provided by the states, (8) whether state programs 
include criteria for siting new units; (9) the extent of requirements 
for corrective action, post-closure monitoring and maintenance; (10) 
the state's pattern of active enforcement and public involvement; and 
(11) whether or not these facilities have insurance against 
catastrophic failures.
    EPA received a substantial amount of information on state programs 
from commenters. Extensive comments were submitted by a coalition of 
environmental groups, outlining the alleged gaps in state regulatory 
programs applicable to the management of CCR. These comments contained 
a comprehensive analysis of 37 state programs based on the findings of 
the DOE/EPA 2006 report as well as on an independent compilation of 
state program requirements. According to these commenters' analysis, 
only four states (representing approximately four percent of the CCR 
generated in the U.S. in 2005) required groundwater monitoring in all 
new and existing landfills, and only six states (representing 
approximately 19 percent of the CCR generated in 2005) required 
groundwater monitoring in all new and existing surface impoundments; 
only five states (representing approximately seven percent of the CCR 
generated in 2005) required composite liners for all new landfills; and 
only four states (representing approximately 19 percent of the CCR 
generated) required composite liners for all new surface impoundments. 
The commenters' analysis discounted any state law that included any 
provision that granted permit writers discretion to modify the 
requirement on a case-by-case basis, and/or to grant waivers and 
exemptions based on the waste's toxicity, onsite location, and 
management practice.
    EPA also received comments from ASTSWMO, the Environmental Council 
of the States (ECOS), and 36 individual states. In its comments, 
ASTSWMO submitted a report with revisions of the aggregated statistics 
in its 2009 report, which they claim demonstrated that state CCR 
programs were more robust than described in the proposed rule. These 
commenters generally agreed with EPA's conclusion that state 
requirements for key CCR requirements are typically more robust for 
landfills than for surface impoundments. ASTSWMO's comments included 
the following examples: 71 percent of the surveyed states required a 
liner for landfills, compared to 65 percent that required that surface 
impoundments be lined; 87 percent of surveyed states required 
groundwater monitoring at landfills, compared to 67 percent of states 
that required groundwater monitoring at surface impoundments; and while 
83 percent of surveyed states required structural stability monitoring 
at landfills, only 64 percent of surveyed states required it at surface 
impoundments. The sole exception related to permit requirements, where 
the report claimed that 91 percent of the surveyed states required a 
permit of some type for surface impoundments, as compared to 86 percent 
of states that required a permit for landfills. In addition, ASTSWMO 
claimed that all 42 surveyed states had the authority to require 
remediation. The report also alleged that in 43 of 44 states, states 
had the authority to require surface impoundments to implement repair 
and maintenance efforts during operation. ASTSWMO also claimed that 43 
out of 44 states required that steps be taken to protect human health 
and the environment, and that 41 of 43 states also had authority to 
require closure.
    According to this revised survey, state requirements also vary with 
respect to whether they applied to all waste units, or only to new 
units or lateral expansions. ASTSWMO stated that in 34 percent of the 
surveyed states, liner requirements applied equally to new and existing 
landfills, and to both existing and new surface impoundments in 46 
percent of the surveyed states. Similarly, ASTSWMO stated that 
groundwater monitoring was required for both existing and new landfills 
in 82 percent of the surveyed states, and to both existing and new 
surface impoundments in 74 percent of the surveyed states.
    Nineteen states and state organizations also directly responded to 
the environmental groups' report by submitting comments on their 
programs, although only four of these states were among the leading CCR 
generators: Kentucky, North Dakota, Ohio, and Michigan. These states 
identified specific instances where the assertions made by the 
environmental groups were factually incorrect or omitted relevant 
information. In response to both the proposed rule and the NODA (76 FR 
63252, October 12, 2011) most states provided only summaries of their 
regulatory programs rather than detailed descriptions.
    As EPA explained in the proposed rule, there are significant 
limitations to the kind of aggregated survey statistics presented in 
ASTSWMO's comments. Such statistics fail to provide the information 
necessary to meaningfully address the question of how, in practice, 
state programs regulate the relevant risks presented by the management 
or disposal of CCR, which was the issue that EPA explained was 
necessary to resolve. For example, even assuming that 91 percent of the 
surveyed states actually do require a permit of some type for surface 
impoundments, this provides no information on the nature or extent of 
the specific requirements in the permit. As noted in the proposal, most 
CCR surface impoundments are regulated under a NPDES permit, and while 
the risks from effluent discharges to navigable waters are addressed, 
these units are not subject to the provisions designed to protect 
groundwater, such as liners or groundwater monitoring. Nor does it 
address the extent of the requirement; for example, although Texas 
generally requires landfills to be permitted and to monitor 
groundwater, the majority of CCR units are exempt from these 
requirements because all industrial wastes managed on-site (i.e., any 
site owned by the generator, up to 50-miles away from the generator's 
facility) are exempt. Finally, since the ASTSWMO survey does not 
identify the individual surveyed states but merely presents aggregated 
statistics, this information cannot be correlated with the amount of 
CCR generated, which significantly limits its value; for example, 
information demonstrating the strength of the regulatory program in a 
state responsible for two percent of the net CCR generated nationally 
is less significant than similar information on a state responsible for 
25 percent of the net CCR generated.
    In addition to the information provided by commenters, EPA 
independently reviewed state statutes and regulations, with a more 
detailed focus on the 16 states responsible for approximately 74 
percent of the CCR generated in 2009. It is clear from this

[[Page 21324]]

review, as well as from information submitted by the commenters, that 
the degree of state regulatory oversight of these wastes and the 
overall protectiveness of the particular state programs varies widely.
    Overall, the information from commenters and from EPA's own review 
of state programs generally confirms EPA's original conclusion that 
significant gaps remain in many state programs. Some programs provide 
minimal or no regulatory oversight of CCR units. For example, Arizona, 
New Mexico, and Utah have no regulations applicable to CCR units or 
entirely exempt CCR from state regulations governing solid waste. 
Similarly, Mississippi, Montana, and Texas (the largest coal-ash 
producer) exempt the on-site disposal of CCR (as ``non-hazardous 
industrial solid waste'') from some or all key requirements, such as 
permits or groundwater monitoring.\29\ Such exemptions would cover most 
of the disposal of CCR within the state, as the majority of utilities 
dispose of their CCR on-site. Other states, such as Florida, Indiana, 
Ohio and Pennsylvania, exempt CCR landfills or ``monofills'' from many 
requirements. For example, Indiana regulations consider surface 
impoundments that are dredged at least annually to be ``storage units'' 
that are exempt from solid waste regulations, including from corrective 
action requirements. Many of these states are among the leading 
generators of CCR wastes. In total, EPA estimates that approximately 20 
percent of the net disposable CCR is entirely exempt from state 
regulatory oversight.
---------------------------------------------------------------------------

    \29\ See 30 TX ADC 335.2(d);
---------------------------------------------------------------------------

    State programs that entirely exempt CCR management from regulatory 
oversight, however, are the exception. Most states do regulate the 
management of CCR to varying degrees, although the particular 
requirements can vary significantly. Still, some general conclusions 
can be drawn.
    Most CCR surface impoundments are permitted exclusively under NPDES 
or other surface water pollution prevention programs. In these states, 
requirements to protect groundwater, such as liners or groundwater 
monitoring systems, are frequently less robust than the corresponding 
requirements applicable to CCR landfills.
    Many state programs require that new disposal units be lined and 
groundwater monitoring systems installed, although many exempt existing 
waste units from the liner and groundwater monitoring requirements. 
Consequently, for newer units, the facts are less alarming: 89 percent 
of the 114 CCR surface impoundments constructed between 1994 and 2010 
have liners, and 70 percent have composite liners. Similarly, 37 of 45 
CCR surface impoundments EPA surveyed had installed groundwater 
monitoring systems. By contrast, 79 percent of the landfills 
constructed during this timeframe had installed liners, but only 58 
percent were composite-lined. However the majority of the older (pre-
1994) waste units still lack liners; 63 percent of older landfills have 
no liners and 63 percent and 24 percent of older surface impoundments 
have either no liners or clay liners, respectively.
    Information on the extent of groundwater monitoring at older units 
was either unavailable, or was too unreliable to support any 
conclusions as to the overall number or percentage of older units with 
groundwater monitoring systems in most states. ASTSWMO's comments in 
response to the October 2011 NODA identified eight states \30\ that 
required groundwater monitoring at existing facilities, but only a few 
of these states addressed this issue in their comments. EPA has some 
anecdotal evidence on the status of groundwater monitoring in six 
states, including four states that are among the leading CCR 
generators. In the wake of the Kingston TVA spill, groundwater 
monitoring wells were installed at 12 of Illinois's existing surface 
impoundments, almost doubling the number of monitored surface 
impoundments in the state. However, 55 additional surface impoundments, 
both active and inactive, still lack groundwater monitoring systems. In 
Ohio, 44 CCR units, out of a total of 57 CCR units in the state (42 
surface impoundments and 15 landfills) still lack groundwater 
monitoring, even though all of the surface impoundments were permitted 
decades ago under Ohio's NPDES program. Ohio acknowledged in their 
comments that the extent of groundwater risks in the state is poorly 
documented, as 40 out of 44 unlined CCR units do not have a groundwater 
monitoring system. In sum, the available information is limited, but at 
least some of that information indicates that significant gaps remain 
with respect to the implementation of groundwater monitoring 
requirements under some state regulatory programs.
---------------------------------------------------------------------------

    \30\ Georgia, Illinois, Indiana, Iowa, Montana, Ohio, 
Pennsylvania, and South Carolina.
---------------------------------------------------------------------------

    Of the states that require groundwater monitoring, most appear to 
require monitoring wells to be placed around the waste unit boundary, 
although the distance from the unit boundary varies from 50 feet to 150 
meters. However, some state programs also authorize a buffer zone or a 
``zone of discharge,'' which allows the facility to defer remediation 
of groundwater contamination for some period of time, usually until the 
contaminant plume has migrated to the facility site boundary. Florida, 
Illinois, North Dakota, and Tennessee are among that states with such a 
regulatory provision. For example, under Florida regulations, primary 
and secondary maximum contaminant levels (MCLs) do not apply even 
beyond the ``zone of discharge,'' absent a specific order by state 
regulatory authorities.
    Most state programs allow the state regulatory authority to grant 
variances or exemptions for some or all of the requirements based on 
site-specific factors. For example, all of the following states require 
groundwater monitoring at CCR surface impoundments, but also authorize 
the regulatory authority to exempt or waive those requirements: 
Alabama, Florida, Georgia, Illinois, Indiana, Kentucky, North Carolina, 
North Dakota, Pennsylvania, and West Virginia. Contrary to the analysis 
presented by the environmental groups' comments, the mere fact that 
state law grants a permit authority the discretion to tailor 
requirements to account for a facility's site specific conditions does 
not support a conclusion that the regulatory program is necessarily 
inadequate. In fact, EPA noted in the proposal that one of the 
strengths of the subtitle C program was that, as a result of the permit 
process, requirements could be tailored to account for site specific 
conditions. Nor does the existence of a waiver process provide any 
evidence of actual practices; in their comments, a few states 
acknowledged that state law allowed for variances, but asserted that 
none had been requested.
    To complicate matters further, several states explained that while 
state law does not mandate certain requirements, state regulatory 
authorities have, in practice, begun to require them in more recent 
permits. For example, several states, including Ohio, Texas, Michigan, 
Florida, and Kentucky, noted that recent practice was to require older 
disposal units to retrofit or close where they failed to meet relevant 
standards. Similarly, it appears that in the 16 leading CCR-generating 
states, 94 percent of new landfills have installed liners (either 
composite or clay), although only 19 percent of these state programs 
actually mandate CCR landfills to install a liner. And although only 
six percent of these state programs require installation of a liner in 
a new surface impoundment, 75 percent of

[[Page 21325]]

new CCR surface impoundments in these states are lined.
    All of this information suggests that, at least in some cases, the 
concerns raised in the proposal regarding the protectiveness of state 
programs remain warranted. But it also is clear it would be impossible 
to accurately evaluate whether, in practice, state programs are 
protective without reviewing individual permit decisions and permit 
requirements. Such an evaluation would necessarily involve not only a 
review of the specific permit requirements, but also the site 
conditions and other factual bases supporting the decision to impose 
the particular requirements. Unfortunately, this information was not 
provided by commenters or found in any source currently available to 
the Agency.
3. Documented Cases in Which Danger to Human Health or the Environment 
From Surface Run-off or Leachate Has Been Proved
    In the proposed rule, EPA described the information it had compiled 
on specific cases where CCR mismanagement had caused harm to human 
health or the environment since the 2000 Regulatory Determination. 
Specifically, EPA explained that it had identified 27 proven damage 
cases: 17 cases of damage to groundwater, and ten cases of damage to 
surface water, seven of which are ecological damage cases. Sixteen of 
the 17 proven damage cases to groundwater involved disposal in unlined 
units; for the one additional unit, it is unknown whether the unit was 
lined. EPA also identified 40 potential damage cases to groundwater and 
surface water. The Agency noted that these numbers likely 
underestimated the number of damage cases and its expectation that 
additional cases of damage would be found if a more comprehensive 
evaluation was conducted, particularly since much of this waste has 
been (and continues to be) managed in unlined disposal units. EPA also 
noted its concern that several of the new damage cases involved 
activities that differ from prior damage cases, including the 
catastrophic release of waste due to the structural failure of CCR 
surface impoundments, such as the dam failures that occurred in Martins 
Creek, Pennsylvania and Kingston, Tennessee, as well as the large-scale 
placement, akin to disposal, of CCR, under the guise of ``beneficial 
use.''
    EPA noted as well that it had received new reports from industry 
and environmental and citizen groups regarding damage cases. Industry 
provided information to demonstrate that many of EPA's listed proven 
damage cases did not meet EPA's criteria for a damage case to be 
considered ``a proven damage case,'' that had been developed for 
purposes of the Bevill Regulatory Determinations. Environmental and 
citizen groups, on the other hand, had submitted reports alleging the 
existence of more recent damage cases beyond those EPA had previously 
documented.
    EPA raised questions concerning the following areas associated with 
the damage cases; first, whether the damage cases discovered to date 
accurately reflected the true number of damage cases associated with 
the mismanagement of CCR. Second, EPA highlighted concern regarding the 
accuracy of the available information on damage cases, as in certain 
instances, much of the information was largely anecdotal. EPA therefore 
specifically solicited comments from state regulatory authorities and 
the facilities involved with the incidents, in the hope of obtaining 
direct evidence of the facts in each case and to obtain a better 
understanding of the nature of the damage caused by past and current 
management practices. For the same reason, on October 12, 2011, EPA 
published a NODA, soliciting comment on the extensive reports received 
during the original comment period on the proposed rule. (See 76 FR 
63252.)
    As discussed in more detail in Unit XI of this document, EPA 
received a significant number of comments on this topic, both during 
the original comment period on the proposal, and in response to the 
NODA. EPA received information on additional damage cases from a number 
of citizen groups, including the report from Environmental Integrity 
Project and Earthjustice titled, ``Out of Control: Mounting Damages 
From Coal Ash Waste Sites,'' which presented information on 31 alleged 
CCR damage cases that were not included or were not recognized as 
damage cases in EPA's July 2007 report. EPA also received an August 26, 
2010 report by the Environmental Integrity Project, Earthjustice, and 
the Sierra Club titled ``In Harm's Way: Lack of Federal Coal Ash 
Regulations Endangers Americans and Their Environment,'' which 
presented an additional 39 alleged CCR damage cases.\31\ EPA also 
received information on ten additional damage cases from state 
officials in Michigan and Wisconsin.
---------------------------------------------------------------------------

    \31\ EPA also received several additional reports that contained 
allegations of further damage cases. However, because these were 
submitted after the close of the comment period, EPA did not 
evaluate these damage cases for this rulemaking or otherwise 
consider the information in those reports.
---------------------------------------------------------------------------

    EPRI submitted two draft reports titled ``Evaluation of Coal 
Combustion Product Damage Cases: Volume 1: Data Summary and 
Conclusions'' (finalized in July 2010), and ``Evaluation of Coal 
Combustion Product Damage Cases: Volume 2: Case Summaries'' (finalized 
in September 2010). In these reports, EPRI provided information that, 
they claimed, showed that many of EPA's previously identified 
``proven'' damage cases did not meet EPA's criteria for a damage case 
to be considered ``proven.'' In response to the 2010 NODA, USWAG 
submitted a report that reviewed the 70 additional damage cases 
submitted by citizen groups as part of their comments on the proposed 
rule. These reports focused primarily on the degree to which the 
contamination had been contained ``on-site'' or had migrated off-site 
of the facility.
    In Unit XI of this document, EPA discusses at length all of the 
comments received and its subsequent analysis of the information 
obtained throughout the rulemaking. In sum, after analyzing all of the 
information submitted in response to this rulemaking, EPA has confirmed 
a total of 157 cases, both proven and potential, in which CCR 
mismanagement has caused damage to human health and the environment. 
Although EPA expects that additional damage cases will be discovered in 
response to the installation of the groundwater monitoring systems 
required by the final rule, overall EPA has a significantly better 
understanding of the extent and nature of the damage caused by CCR 
mismanagement than when the proposed rule was issued. EPA has 
sufficient confidence in the veracity of the information collected to 
rely on it in making decisions in this rule.
4. Conclusions
    EPA explained in the proposed rule that the decision on whether to 
retain the Bevill exemption is inherently discretionary, in that it 
ultimately requires the Agency to make a policy judgment as to the 
appropriate balance among the eight statutory factors. Chief among the 
several principles that EPA stated would guide its decision was that 
any action must protect human health and the environment. To this end, 
EPA singled out three key areas of analyses that bear directly on that 
guiding principle: the extent of the risks posed by mismanagement of 
CCR; the adequacy of state programs to ensure proper management of CCR; 
and the extent and nature of damage cases.
    The first of these largely related to the 2010 quantitative risk 
assessment of the potential for contamination to

[[Page 21326]]

groundwater. During the rulemaking, EPA received information that 
allowed the Agency to resolve two of the four primary uncertainties 
identified in the proposal. The risk assessment has been revised with 
updated pore water concentration data and with LEAF leachate data, and 
accounts for the potential reduction of contaminants reaching drinking 
water sources due to interception of contamination by surface water 
bodies. However, two sources of uncertainty remain: the potential 
effect of pollution control technologies on the CCR characteristics, 
and the appropriate IRIS value for arsenic.
    EPA's risk assessment evaluated current management practices, and 
generally did not attempt to account for or evaluate the potential for 
future changes in the wastes. While EPA has great confidence in the 
assessment, its ability to definitively resolve this question is 
therefore limited, given the very real potential for significant 
changes in CCR characteristics and constituents in the near future, due 
to the required installation of pollution control technologies. Changes 
in the CCR characteristics are particularly significant, as the risk 
assessment concluded that one of the parameters most likely to affect 
the agency's risk estimates was the characteristic of the wastes.
    With respect to the second area, EPA is unable to reach any 
definitive conclusions as to whether state regulatory programs are so 
deficient that the level of federal oversight under subtitle C is 
necessary. Specifically, EPA cannot determine from the available 
information how states, in practice, have implemented regulatory 
requirements. At this point, only limited conclusions are possible.
    Clear deficiencies exist in some state regulatory programs, and 
questions remain with respect to others. And many of these concerns 
exist with respect to programs in states responsible for the majority 
of CCR generation and disposal. However, most state programs, although 
they vary considerably, are not clearly deficient on their face. But it 
is equally clear that exclusive reliance on the regulatory programs as 
written, without any examination of how states have implemented those 
requirements in practice, would not support sweeping conclusions about 
the overall adequacy of state programs. It is critical to ensure that 
any decision accurately accounts for how the states have exercised 
their judgment in implementing those requirements, before concluding 
that state programs cannot adequately oversee the management of CCR 
without the degree of federal involvement mandated by subtitle C. 
Notwithstanding EPA's inability to draw conclusions on the overall 
adequacy of state programs, the high degree of variation across state 
programs strongly supports the need for federal requirements to 
establish a consistent national standard of groundwater and human 
health protection.
    In contrast to the other two areas identified in the proposed rule, 
while some uncertainty remains with respect to the damage cases--
namely, whether the 157 identified to date represent the total number 
of damage cases caused by CCR mismanagement, and whether some of the 
``potential'' damage cases should be classified as ``proven'' damage 
cases--at this point, EPA has concluded that the available information 
provides a sufficient evidentiary base on which decisions can be made. 
In the absence of the necessary information on two of the three 
critical areas, however, EPA cannot reach any final conclusions 
regarding the appropriate balance among the eight statutory factors. 
Consequently, EPA is also not reaching any final conclusions as to 
whether a damage case is best categorized as ``proven'' or 
``potential.'' Such a finding is relevant only to the Bevill Regulatory 
Determination.
    However, as discussed in more detail in Unit XI of this document, 
the damage cases provide extremely valuable evidence that is directly 
relevant to the question of whether and how to regulate CCR waste. For 
example, the damage cases provide ``real world'' evidence against which 
to compare EPA's risk modeling estimates, such as evidence regarding 
the frequency with which particular constituents leach into 
groundwater. They also provide direct evidence regarding specific waste 
management practices at electric utilities, along with the potential 
consequences of those practices. Finally, both the specifics of the 
damage cases and the fact that they continue to occur provide strong 
evidence of the need for this rule under subtitle D while EPA obtains 
the information that will allow the Agency to make a final Regulatory 
Determination for these wastes.
    Thus, even though EPA is not able to reach a final conclusion on 
the Regulatory Determination for these wastes, the totality of the 
information in the rulemaking record clearly demonstrates that the 
risks associated with the current management and disposal of CCR remain 
substantial. EPA's risk assessment concluded that the cancer risks from 
unlined surface impoundments ranged from 3 x 10-4 for 
trivalent arsenic to 4 x 10-5 for pentavalent arsenic. Non-
cancer risks from these same units also significantly exceeded EPA's 
level of concern, with estimates ranging from an HQ of 2 for thallium, 
to HQs \32\ of 4 for molybdenum and 8 for trivalent arsenic. The risks 
associated with unlined landfills were also estimated to be 
significant, with cancer risks of 2 x 10-5 for trivalent 
arsenic. It is important to note that these risk numbers are based on 
national disposal practices. Risks at an individual site may be even 
higher based on individual site conditions, waste characteristics, and 
management practices. EPA's risk assessment identified the potential 
for higher risks based on different waste pH values and management 
practices. Multiple constituents presented higher risks when considered 
in waste management units that co-dispose both ash and coal refuse at 
more acidic pHs or FGD wastes at more basic pHs. For example, the 
modeled cancer risks for the co-disposal of ash and coal refuse (pH 
1.7-8.2) ranged between 10-3 for trivalent arsenic to 4 x 
10-4 for pentavalent arsenic. Non-cancer risks were 
similarly high, ranging between and an HQ of 13 for cobalt, and HQs of 
14 for pentavalent arsenic to 26 for trivalent arsenic, based on the 
ingestion of contaminated drinking water. Although this management 
practice is declining, recent information indicates that approximately 
five percent of facilities continue to co-dispose of ash and coal 
refuse in surface impoundments.
---------------------------------------------------------------------------

    \32\ For more information on HQs please see Unit X. Risk 
Assessment of this preamble.
---------------------------------------------------------------------------

    Moreover, EPA's risk estimates are consistent with the continued 
damage cases compiled through this rulemaking. As further discussed in 
Unit XI of this document, EPA has confirmed that 157 cases of proven or 
potential contamination of groundwater have occurred in states across 
the nation since the initial Regulatory Determination. These damage 
cases were primarily associated with unlined units and were most 
frequently associated with releases of arsenic. While new units are 
typically constructed with composite liners, which under EPA's current 
risk assessment adequately mitigate the risks, older units still 
comprise the overwhelming majority of currently operating units. EPA's 
data show that approximately 63 percent of currently operating surface 
impoundments and landfills are unlined, and thus more prone to leach 
contaminants into groundwater. Analysis of the information from the 
damage cases also demonstrates that unlined surface

[[Page 21327]]

impoundments typically operate for 20 years before they begin to leak. 
Most of the currently operating surface impoundments are between 20 and 
40 years old.
    The age of the units also has implications for their structural 
stability and the potential for catastrophic releases. Of the 
approximately 735 CCR surface impoundments currently operating in the 
United States, a certain percentage have a great potential for loss of 
human life and environmental damage in the event of catastrophic 
failure. Based on the information collected from EPA's Assessment 
Program, 318 surface impoundments have either a high or significant 
hazard potential rating, at least 13 of which were not designed by a 
professional engineer. Of the total universe of surface impoundments, 
approximately 186 of these units were not designed by a professional 
engineer. Surface impoundments are generally designed to last the 
typical operating life of coal-fired boilers, on the order of 40 years. 
However, many impoundments are aging; based on the subset of units for 
which age data were available, approximately 195 active surface 
impoundments exceed 40 years of age; 56 units are older than 50 years, 
and 340 are between 26 and 40 years old. In recent years, problems have 
continued to arise from these units, which appear to be related to the 
aging infrastructure, and the fact that many units may be nearing the 
end of their useful lives. For example, as a result of the 
administrative consent order issued after the December 2008 spill, TVA 
conducted testing which showed that another dike at TVA's Kingston, 
Tennessee plant had significant safety deficiencies. Collectively, 
these facts indicate a high likelihood that in the absence of any 
regulatory action, such units will leak in the near future, or are 
currently leaking, undetected, since groundwater monitoring is not 
installed at many of these older units. Moreover, damage cases continue 
to occur; in response to EPA's CERCLA 104(e) information request 
letter, a total of 35 units at 25 facilities reported historical 
releases. These range from minor spills to a spill of 0.5 million cubic 
yards of water and fly ash. And as recently as February 2014, CCR 
slurry was released into the Dan River from an inactive surface 
impoundment in North Carolina.
    All of which demonstrates a compelling need for a uniform system of 
requirements to address these risks without waiting for the information 
and analyses necessary to complete a final Regulatory Determination. 
EPA will continue to monitor these critical areas, and will provide the 
public with an additional opportunity to comment on any proposed 
Regulatory Determination, prior to issuing a final Regulatory 
Determination.

B. Final Regulatory Determination Regarding Beneficial Use

    EPA generally proposed to retain the May 2000 Regulatory 
Determination that beneficially used CCR did not warrant federal 
regulation under subtitle C of RCRA. As EPA stated in the May 2000 
Regulatory Determination, ``In the [Report to Congress], we were not 
able to identify damage cases associated with these types of beneficial 
uses, nor do we now believe that these uses of coal combustion wastes 
present a significant risk to human health and the environment. While 
some commenters disagreed with our findings, no data or other support 
for the commenters' position was provided, nor was any information 
provided to show risk or damage associated with agricultural use. 
Therefore, we conclude that none of the beneficial uses of coal 
combustion wastes listed above pose risks of concern.'' (See 65 FR 
32230.) EPA noted that since the original Regulatory Determination, the 
Agency had found no data or other information to indicate that existing 
efforts of states, EPA, and other federal agencies had been inadequate 
to address the environmental issues associated with the beneficial use 
of CCR that were originally identified in the Regulatory Determination. 
EPA explained that it had proposed this approach in recognition that 
some uses of CCR, such as encapsulated uses in concrete, and use as an 
ingredient in the manufacture of wallboard, provide benefits and raise 
minimal health or environmental concerns. Consequently, EPA 
preliminarily concluded that encapsulated uses of CCR, which are common 
in many consumer products, did not merit regulation based on the 
available information.
    However, EPA noted that the issues were more difficult with respect 
to unencapsulated uses of CCR and specifically solicited comment on 
whether such uses should continue to be included as ``beneficial use'' 
under the Bevill exemption. EPA explained that unencapsulated uses have 
raised concerns and therefore merited closer attention. For example, 
the placement of unencapsulated CCR on the land, such as in road 
embankments or in agricultural uses, presented a set of issues similar 
to those that caused the Agency to propose to regulate CCR destined for 
disposal. But the Agency also acknowledged that the amounts and, in 
some cases, the manner in which CCR is used--i.e., subject to 
engineering specifications and material requirements rather than 
landfilling techniques--are potentially very different from land 
disposal.
    EPA is retaining the original 2000 Regulatory Determination for CCR 
that is beneficially used. EPA has made this determination based on 
consideration of the available information and the RCRA section 8002(n) 
study factors. {{
1. Source and Volume of CCR Generated Each Year
    The American Coal Ash Association (ACAA) conducts a voluntary, 
annual survey of the coal-fired electric utility industry to track the 
quantities of CCR generated and beneficially used. According to the 
latest survey, the electric utility industry generated nearly 110 
million tons of CCR in 2012. Approximately 39 million tons of these CCR 
was identified by ACAA as beneficially used in either encapsulated or 
unencapsulated products. An additional 12.8 million tons were placed in 
mine-fill operations, while the remaining 57.8 million tons were 
disposed of in landfills and surface impoundments (ACAA, 2013).\33\
---------------------------------------------------------------------------

    \33\ ACAA (American Coal Ash Association). 2013. 2012 Coal 
Combustion Product (CCP) Production & Use Survey Report. Farmington 
Hills, MI 48331. Available online at: http://www.acaa-usa.org/Portals/9/Files/PDFs/revisedFINAL2012CCPSurveyReport.pdf
---------------------------------------------------------------------------

2. Present Utilization Practices
    Based on the beneficial use rates reported by ACAA, approximately 
50 percent of the CCR beneficially used on an annual basis falls into 
two categories: (1) Fly ash used as a direct substitute for Portland 
cement during the production of concrete (referred to as ``fly ash 
concrete''); and (2) FGD gypsum used as a replacement for mined gypsum 
in wallboard (referred to as ``FGD gypsum wallboard''). Specifically, 
the 2012 ACAA survey indicates that the largest encapsulated beneficial 
uses of CCR, by more than a factor of two, are fly ash used in 
``concrete/concrete products/grout'' (12.6 million tons) and FGD gypsum 
used in ``gypsum panel products'' (7.6 million tons).
3. Potential Danger, if Any, to Human Health or the Environment From 
the Reuse of CCR
    The risks associated with the disposal of CCR stems from the 
specific nature of that activity; that is, the disposal of CCR in 
(often unlined) landfills or surface impoundments, with thousands, if 
not millions, of tons placed in a single

[[Page 21328]]

concentrated location. And in the case of surface impoundments, the CCR 
is managed with water, under a hydraulic head, which promotes rapid 
leaching of contaminants into neighboring groundwater. The beneficial 
uses identified as excluded under the Bevill exemption for the most 
part present a significantly different risk profile.

a. Encapsulated Beneficial Uses

    An encapsulated beneficial use is one that binds the CCR into a 
solid matrix that minimizes mobilization into the surrounding 
environment. Examples of encapsulated uses include, but are not limited 
to: (1) Filler or lightweight aggregate in concrete; (2) a replacement 
for, or raw material used in production of, cementitious components in 
concrete or bricks; (3) filler in plastics, rubber, and similar 
products; and (4) raw material in wallboard production.
    Since publication of the proposal, EPA has developed a methodology 
for evaluating encapsulated beneficial uses. A copy of the methodology 
can be found at http://www2.epa.gov/coalash/methodology-evaluating-encapsulated-beneficial-uses-coal-combustion-residuals. EPA applied 
this methodology to the two largest CCR uses--the use of fly ash as a 
replacement for Portland cement in concrete, and the use of FGD gypsum 
as a replacement for mined gypsum in wallboard. A complete copy of the 
evaluation can be found at http://www.epa.gov/wastes/conserve/imr/ccps/pdfs/ccr_bu_eval.pdf.
    The evaluation considered products that meet relevant physical and 
performance standards, that conform to standard design specifications, 
and that incorporate fly ash and FGD gypsum from pollution control 
devices currently used in the United States. Based on the findings of 
the evaluation, the Agency concluded that environmental releases of 
constituents of potential concern from CCR fly ash concrete and FGD 
gypsum wallboard during use by the consumer are comparable to or lower 
than those from analogous non-CCR products, or are at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors.

b. Unencapsulated Uses

    EPA acknowledged in the proposal that unencapsulated uses generally 
presented more difficult issues than encapsulated uses. CCR can leach 
toxic metals at levels of concern, so depending on the characteristics 
of the CCR, the amount of material placed, how it is placed, and the 
site conditions, there is a potential for environmental concern. 
However, EPA cannot extrapolate from the risk assessments conducted to 
evaluate the management practices associated with CCR landfills and CCR 
surface impoundments, because the exposure patterns are too dissimilar: 
The amounts and manner involved with beneficial use are very different 
than the thousands, if not millions of tons of CCR that are mounded in 
a single concentrated location in a landfill. And the potential 
exposures are entirely unlike surface impoundments, where CCR is 
managed with water under a hydraulic head, which promotes more rapid 
leaching of contaminants. By contrast ``beneficial uses,'' even 
unencapsulated uses, are typically subject to engineering 
specifications, and for certain uses, federal oversight, and material 
requirements. For example, fly ash used as a stabilized base course in 
highway construction is subject to both regulatory standards under the 
U.S. Department of Transportation (DOT) and the Federal Highway 
Administration (FHWA), and engineering specifications, such as the ASTM 
C 593 test for compaction, the ASTM D 560 freezing and thawing test, 
and a seven day compressive strength above 2760 kPa (400 psi). (See 75 
FR 35163-35165 for additional examples.)
    In 1999, EPA conducted a risk assessment of certain agricultural 
uses of CCR, since this practice was considered the most likely to 
raise human health or environmental concerns.\34\ EPA estimated the 
risks associated with such uses to be within the range of 1 x 
10-6. These results as well as EPA's conclusion that the use 
of CCR in agricultural settings was the most likely use to raise 
concerns, caused EPA to conclude that none of the beneficial uses 
identified in the 2000 Regulatory Determination warranted federal 
regulation, because ``we were not able to identify damage cases 
associated with these types of beneficial uses, nor do we now believe 
that these uses of coal combustion wastes present a significant risk to 
human health or the environment.'' (65 FR 32230, May 22, 2000.)
---------------------------------------------------------------------------

    \34\ For more information on this risk assessment see EPA's 
Notice of Regulatory Determination on Wastes from the Combustion of 
Fossil Fuels (65 FR 32214, May 22, 2000).
---------------------------------------------------------------------------

    EPA also noted that beneficially using secondary materials 
conserves natural resources, and can serve as an important alternative 
to disposal.
4. Documented Cases in Which Damage to Human Health or the Environment 
From Surface Run-off or Leachate Has Been Proved
    To date, EPA has seen no evidence of damages from the encapsulated 
beneficial uses of CCR that EPA identified in the proposal. For 
example, there is wide acceptance of the use of CCR in encapsulated 
uses, such as wallboard, concrete, and bricks because the CCR is bound 
into products. However, as of the date of the proposed rule, seven 
proven damage cases associated with unencapsulated uses have occurred, 
in which large quantities of unencapsulated CCR were used 
indiscriminately to re-grade the landscape or to fill old quarries or 
gravel pits. The proposed rule discussed two of these cases. (See 75 FR 
35147.) The first case was in Gambrills, Maryland and involved the 
disposal of fly ash and bottom ash (beginning in 1995) in two sand and 
gravel quarries. EPA considers this site a proven damage case, because 
groundwater samples from residential drinking wells near the site 
include heavy metals and sulfates at or above groundwater quality 
standards, and the state of Maryland is overseeing remediation. The 
second case is the Battlefield Golf Course in Chesapeake, Virginia 
where 1.5 million yards of fly ash were used as fill and to contour a 
golf course. Groundwater contamination above MCLs has been found at the 
edges and corners of the golf course, but not in residential wells. An 
EPA study in April 2010, established that residential wells near the 
site were not impacted by the fly ash and, therefore, EPA does not 
consider this site to be a proven damage case. However, due to the 
onsite groundwater contamination, EPA considers this site to be a 
potential damage case.
    During the development of this final rule, EPA obtained information 
on a comparable situation in which large quantities of unencapsulated 
CCR were placed on the land in a manner that presented significant 
concerns. The AES coal-fired power plant in Puerto Rico lacked capacity 
to dispose of their CCR on-site, and off-site landfills in Puerto Rico 
were prohibited from accepting CCR. In lieu of transporting their CCR 
off of the island for disposal, AES created an aggregate (``AGREMAX'') 
with the CCR generated at their facility, and used the aggregate as 
fill in housing developments and in road projects. Over two million 
tons of this material was used between 2004 and 2012.
    Currently, there is insufficient information to determine whether 
groundwater has been contaminated as

[[Page 21329]]

a result of this practice, and thus, EPA cannot classify this as either 
a proven or potential ``damage case.'' Nevertheless, the available 
facts illustrate several of the significant concerns associated with 
unencapsulated uses. Specifically, the AGREMAX was applied without 
appropriate engineering controls and in volumes that far exceeded the 
amounts necessary for the engineering use of the materials. Inspections 
of some of the sites where the material had been placed showed use in 
residential areas, and to environmentally vulnerable areas, including 
areas close to wetlands and surface waters and over shallow, sole-
source drinking water aquifers. In addition, some sites appeared to 
have been abandoned.
    Consistent with the proposed rule, EPA does not consider the 
practices described in this section to be beneficial use, but rather 
waste management that would be subject to the requirements of the final 
rule.
5. Alternatives to Current Disposal Methods, the Costs of Such 
Alternatives, and the Impact of Such Alternatives on the Use of Coal 
and Other Natural Resources
    The beneficial use of CCR is a primary alternative to current 
disposal methods. And as EPA has repeatedly concluded, it is a method 
that, when performed correctly, can offer significant environmental 
benefits, including greenhouse gas (GHG) reduction, energy 
conservation, reduction in land disposal (along with the corresponding 
avoidance of potential CCR disposal impacts), and reduction in the need 
to mine and process virgin materials and the associated environmental 
impacts.

a. Greenhouse Gas and Energy Benefits

    The beneficial use of CCR reduces energy consumption and GHG 
emissions in a number of ways. Three of the most widely recognized 
beneficial applications of CCR are the use of coal fly ash as a 
substitute for Portland cement in the manufacture of concrete, the use 
of FGD gypsum as a substitute for mined gypsum in the manufacture of 
wallboard, and the use of CCR as a substitute for sand, gravel, and 
other materials in structural fill. Reducing the amount of cement, 
mined gypsum, and virgin fill produced by substituting CCR leads to 
large supply chain-wide reductions in energy use and GHG emissions. 
Specifically, the RIA estimates three-year rolling average of 
53,054,246 million British thermal units (MMBtu) per year in energy 
savings and 11,571,116 tons per year in GHG (i.e., carbon dioxide and 
methane) emissions reductions in 2015. This estimate is likely to 
underestimate the total benefits that can be achieved from all 
beneficial uses. Furthermore, the use of fly ash generally makes 
concrete stronger and more durable. This results in a longer lasting 
material, thereby marginally reducing the need for future cement 
manufacturing and corresponding avoided emissions and energy use.

b. Benefits From Reducing the Need To Mine and Process Virgin Materials

    CCR can be substituted for many virgin materials that would 
otherwise have to be mined and processed for use. These virgin 
materials include limestone to make cement, and Portland cement to make 
concrete; mined gypsum to make wallboard, and aggregate, such as stone 
and gravel for uses in concrete and road bed. Using virgin materials 
for these applications requires mining and processing, which can impair 
wildlife habitats and disturb otherwise undeveloped land. It is 
beneficial to use secondary materials--provided it is done in an 
environmentally sound manner--that would otherwise be disposed of, 
rather than to mine and process virgin materials, while simultaneously 
reducing waste and environmental footprints. Reducing mining, 
processing and transport of virgin materials also conserves energy, 
avoids GHG emissions, and reduces impacts on communities.

c. Benefits From Reducing the Disposal of CCR

    Beneficially using CCR instead of disposing of it in landfills and 
surface impoundments also reduces the need for additional landfill 
space and any risks associated with their disposal. In particular, the 
United States disposed of over 57.8 million tons of CCR in landfills 
and surface impoundments in 2012, which is equivalent to the space 
required of 20,222 quarter-acre home sites under eight feet of CCR.
    As discussed in the final rule RIA, the current beneficial use of 
CCR as a replacement for industrial raw materials (e.g., Portland 
cement, virgin stone aggregate, lime, gypsum) provides substantial 
annual life cycle environmental benefits for these industrial 
applications. Specifically, the three-year rolling average of 
environmental benefits estimated for 2015 includes: (1) 53,054,246 
MMBtu per year in energy savings; (2) 1,661,900 million gallons per 
year in water savings; (3) 11,571,116 tons per year in GHG (i.e., 
carbon dioxide and methane) emissions reductions; (4) 45,770 tons of 
criteria air pollutant (i.e., NOX, SOX, 
particulate matter, and CO) emissions reductions; and (5) 3,207 pounds 
of toxic air pollutant (i.e., mercury and lead) emissions reductions. 
All together, the beneficial use of CCR in 2015 is estimated to provide 
over $2.3 billion in annual national environmental benefits. In 
addition, since EPA estimates annual baseline disposal costs of 
approximately $2.4 billion for the just over 50 percent of tons 
disposed each year, current beneficial use and minefilling also result 
in annual material and disposal cost savings of approximately $2 
billion annually.
6. Current and Potential Utilization of CCR
    In 2012, nearly 36 percent (39 million tons) of CCR were 
beneficially used (excluding minefill operations) and nearly 12 percent 
(12.8 million tons) were placed in minefills. (This compares to 23 
percent of CCR that were beneficially used, excluding minefilling, at 
the time of the May 2000 Regulatory Determination, and represents a 
significant increase.)
7. Conclusions
    On balance, after considering all of the available information, EPA 
has concluded that the most appropriate approach toward beneficial use 
is to retain the May 2000 Regulatory Determination that regulation 
under subtitle C of the beneficial use of CCR is not warranted. EPA has 
also determined that regulation under subtitle D is generally not 
necessary for these beneficial uses.
    As discussed in the preceding section, the most important of the 
section 8002(n) factors are those relating to the potential risks to 
human health and the environment. See e.g., Horsehead Resource 
Development Co. v. EPA, 16 F.3d 1246, 1258 (D.C. Cir, 1994) (Upholding 
EPA's interpretation that wastes resulting from the combustion of 
mixtures of Bevill-exempt and non-exempt wastes could only retain 
Bevill-exempt status so long as the combustion waste remained of low 
toxicity); EDF v. EPA, 852 F.2d 1316, 1328-1329 (D.C. Cir. 1988) 
(Overturning EPA rule that included as Bevill exempt, wastes that were 
not of low toxicity). EPA is adopting this Regulatory Determination in 
recognition that many uses of CCR, such as encapsulated uses in 
concrete, and use as an ingredient in the manufacture of wallboard, 
provide environmental benefits and raise minimal health or 
environmental concerns. To date, the information available does not 
demonstrate the existence of any risks associated with encapsulated 
uses of CCR that merit

[[Page 21330]]

regulation under either subtitle C or subtitle D of RCRA.
    While there can be some risks associated with unencapsulated uses--
for example, the placement of unencapsulated CCR on the land, such as 
in large scale fill operations or in agricultural uses, depending on 
the specific site conditions--in general the amounts and, in some 
cases, the manner in which they are used are very different than land 
disposal. For example, agricultural uses involve the placement of 
inches rather than tons of CCR, and placement of CCR in a thin layer 
rather than mounded in a single concentrated location. In addition, 
these uses are subject to engineering specifications and materials 
requirements, which will limit the ultimate amount of material placed 
on the land.
    EPA recognizes that several proven damage cases involving the 
large-scale placement, akin to disposal, of CCR have occurred under the 
guise of ``beneficial use''-- the ``beneficial'' use being the filling 
up of old quarries or gravel pits, or the re-grading of landscape with 
large quantities of CCR. EPA did not consider this type of use as a 
``beneficial'' use in its May 2000 Regulatory Determination, and still 
does not consider this type of use to be covered by the exclusion. 
Therefore, the final rule explicitly removes these types of uses from 
the category of beneficial use, and from this Regulatory Determination. 
As discussed in the next section of this preamble, EPA has adopted 
criteria in the final rule to ensure that inappropriate uses that 
effectively are disposal will be regulated as disposal. The final rule 
expressly defines the placement of CCR in sand and gravel pits or 
quarries as disposal in a landfill. In addition, the final rule 
provides that the use of large volumes of CCR in restructuring 
landscape that does not meet specific criteria will constitute 
disposal.
    While EPA has not definitively concluded that all unencapsulated 
beneficial uses are ``safe,'' based on the current record for this 
rulemaking, EPA is unable to point to evidence demonstrating that the 
unencapsulated uses subject to this Determination warrant federal 
regulation. While the absence of demonstrated harm in this instance is 
not proof of safety, neither is the lack of information proof of 
risk.\35\
---------------------------------------------------------------------------

    \35\ The Agency is currently developing a Framework to address 
the risks associated with the beneficial use of unencapsulated 
materials. This Framework is expected to be finalized in 2015. See 
Unit VI of this document for more information.
---------------------------------------------------------------------------

    In this regard, EPA notes that many states have developed 
beneficial use programs that allow the use of CCR, provided they are 
demonstrated to be non-hazardous materials; and many require a site 
specific assessment before authorizing placement on the land of large 
amounts of unencapsulated CCR. For example, Wisconsin's Department of 
Natural Resources has developed a regulation (NR 538 Wis. Adm. Code), 
which includes a five-category system to allow for the beneficial use 
of industrial by-products, including coal ash, provided they meet the 
specified criteria. In addition, the ASTSWMO 2006 Beneficial Use Survey 
Report states that a total of 34 of the 40 reporting states, or 85 
percent, indicated they had either formal or informal decision-making 
processes or beneficial use programs relating to the use of solid 
wastes. (http://www.astswmo.org/Files/Policies_and_Publications/Solid_Waste/2007BUSurveyReport11-30-07.pdf) \36\ Because EPA has not 
identified significant risks associated with the beneficial uses 
covered by this Regulatory Determination, the adequacy of these state 
programs does not factor into EPA's Determination. Nevertheless, to the 
extent that that these materials do have the potential to pose risk at 
an individual site, the fact that many states exercise regulatory 
oversight of these materials provides an additional level of assurance.
---------------------------------------------------------------------------

    \36\ EPA has worked with the states to support the development 
of a national database on state beneficial use determinations. 
Information on the beneficial use determination database can be 
found on the Northeast Waste Management Officials' Association 
(NEWMOA) Web site at http://www.newmoa.org/solidwaste/bud.cfm. This 
database helps states share information on beneficial use decisions 
providing for more consistent and informed decisions.
---------------------------------------------------------------------------

    Finally, EPA does not wish to inhibit or eliminate the measurable 
environmental and economic benefits derived from the use of this 
valuable material given the current lack of evidence affirmatively 
demonstrating an environmental or health risk. Consequently, EPA is 
confident that the combination of the final rule, EPA guidance, current 
industrial standards and practices, and in many cases, state regulatory 
oversight is sufficient to address concerns associated with the 
beneficial uses to which this Determination applies.

V. Development of the Final Rule--RCRA Subtitle D Regulatory Approach

    As previously discussed in Unit II of this document, the authority 
to develop and promulgate the national minimum criteria governing the 
disposal of CCR in landfills and surface impoundments is found under 
the provisions of sections 1008(a), 4004, and 4005(a) of RCRA (i.e., 
subtitle D of RCRA). These authorities, however, do not provide EPA 
with the ability to issue permits, require states to issue permits, 
approve state programs to operate in lieu of the federal program, or to 
enforce any of the requirements addressing the disposal of CCR. 
Consequently, EPA designed the proposed RCRA subtitle D option to 
ensure that the requirements will effectively protect human health and 
the environment within those limitations. The final rule establishes 
self-implementing requirements--primarily performance standards--that 
owners or operators of regulated units can implement without any 
interaction with regulatory officials.
    In developing the subtitle D option for the proposal, EPA 
considered a number of existing programs as relevant models. EPA drew 
most heavily on the existing 40 CFR part 258 program applicable to 
MSWLFs. While this program does not address CCR disposal in surface 
impoundments, it provided EPA with a general regulatory framework that 
addressed all aspects of disposal in certain land-based units. Given 
the Agency's expansive history and experience with these requirements, 
EPA concluded that the part 258 criteria with certain modifications for 
other land-based disposal units (i.e., surface impoundments) 
represented a reasonable balance between ensuring the protection of 
human health and the environment from the risk of CCR disposal and the 
absence of any regulatory oversight. (See 75 FR 35192-35195.)
    EPA also considered that many of the technical requirements 
developed to specifically address the risks from the disposal of CCR as 
part of the subtitle C alternative would be equally justified under a 
RCRA subtitle D regulatory regime. The factual record--i.e., the risk 
analysis and the damage cases--supporting such requirements was the 
same, irrespective of the statutory authority under which the Agency 
was operating. Thus, several of the provisions under RCRA subtitle D 
either corresponded to the proposal under RCRA subtitle C, or were 
modeled after the existing subtitle C requirements; for example, EPA 
proposed the same MSHA-based structural stability standards for surface 
impoundments under the subtitle C and subtitle D options. However, 
because there is no corresponding guaranteed permit mechanism under the 
RCRA subtitle D requirements, EPA also considered the 40 CFR part 265 
interim status requirements for hazardous waste facilities, which were 
designed to operate in the absence of a permit. These requirements were 
particularly

[[Page 21331]]

relevant in developing the requirements for surface impoundments since 
such units are not regulated under 40 CFR part 258. Beyond their self-
implementing design, these requirements provided a useful model 
because, based on decades of experience in implementing these 
requirements, EPA had assurance that these requirements were protective 
for a variety of waste, under a wide variety of site conditions.
    In an effort to ensure that the proposed RCRA subtitle D 
requirements would achieve the statutory standard of ``no reasonable 
probability of adverse effects on health and the environment'' in the 
absence of guaranteed regulatory oversight, EPA also proposed to 
require facilities to obtain third party certifications and to provide 
enhanced state and public notifications of actions taken to comply with 
the regulatory requirements. Specifically, EPA proposed that certain 
technical demonstrations made by the owner or operator be certified by 
an independent registered professional engineer or hydrologist, in 
order to provide verification and otherwise ensure that the provisions 
of the rule were properly applied. EPA also provided a regulatory 
definition of the term, ``independent registered professional engineer 
or hydrologist,'' to identify the minimum qualifications necessary to 
make these certifications. While EPA acknowledged that relying upon a 
third party certification was not the same as relying upon a state or 
federal regulatory authority and was not expected to provide the same 
level of independence as a state permit program, the availability of 
meaningful third party (i.e., independent) verification provided 
critical support that the rule would achieve the statutory standard, as 
it would provide at least some degree of control over a facility's 
discretion in implementing the rule.
    As part of the notification requirements, EPA further proposed that 
all owners and operators create and maintain an operating record and 
publically accessible Web site, containing comprehensive documentation 
of compliance with the rule. EPA also proposed that owners or operators 
provide notification to the state and the public of third party 
certifications as well as other information documenting actions taken 
to comply with the technical criteria of the rule.

A. The Self-Implementing Approach

    While the vast majority of state and industry commenters supported 
regulating the management of CCR under subtitle D of RCRA, a very 
limited number of commenters favored the proposed self-implementing 
option. Most commenters argued that if the Agency were to adopt the 
proposed subtitle D approach it would most certainly result in parallel 
and redundant regulatory programs for CCR in many states, creating an 
unworkable situation for industry, as well as the state. Some 
commenters argued that under this dual regulatory approach, an owner or 
operator of a CCR unit could conceivably be in non-compliance with both 
a federal requirement and an independently administered state 
regulatory requirement, subjecting the owner or operator to both a 
citizen suit enforcement action in federal court for the alleged 
violation and to a wholly separate enforcement action in state court 
for violation of the parallel state requirement. Commenters argued that 
this regulatory construct made no sense and would waste federal and 
state judicial resources and company resources, as well as possibly 
resulting in inconsistent federal and state court determinations with 
respect to an identical regulatory requirement. It also could result in 
duplicative federal and state penalties for essentially the same 
regulatory infraction.
    Commenters further argued that the prescriptive one-size-fits-all 
approach was overly stringent and inflexible and had the potential to 
greatly disrupt implementation of a state's regulatory programs, which 
have been tailored to provide for site specific conditions and 
situations. Moreover, commenters argued that because of the many state 
regulatory programs addressing CCR disposal, there would be many 
instances where state requirements could be in conflict with, in 
addition to, or separate from the federal requirements and it was 
unclear how these differences would be resolved.
    Many commenters simply argued that a permitting program similar to 
that for MSWLFs was the only viable approach for the regulation of CCR. 
A significant number of commenters, however, proposed various 
alternative approaches for regulating CCR disposal under subtitle D of 
RCRA. One option would have EPA allow qualified state programs to 
directly administer the subtitle D requirements for CCR when the state 
regulatory program meets or exceeds the federal requirements, thereby 
minimizing duplicative regulations and avoiding the self-implementing 
``one size fits all'' approach contained in EPA's proposal. This 
option, commenters reasoned, could be implemented utilizing a process 
developed by the Agency for evaluating whether the state's CCR 
regulations were equivalent to the federal minimum criteria (much like 
EPA does now in the case of MSWLFs under 40 CFR part 258). Another 
suggested approach involved EPA clarifying that a state can be more 
restrictive than the federal rule, and that where a state has a 
subtitle D regulatory program that is more restrictive, the state 
program and permitting process would take precedence over any self-
implementation aspects of a final rule. (The proposed rule had simply 
stated that an owner or operator must comply with any other applicable 
federal, state, tribal or local laws or other requirements.) Commenters 
also proposed a third option, similar to the 40 CFR part 258 program, 
recognizing that EPA cannot approve state programs in this rule. 
Specifically, 40 CFR part 258 provides a definition for ``Director of 
an approved state'' that means they are the chief administrative 
officer of a state agency responsible for implementing the state permit 
program that is deemed to be adequate by EPA under regulations 
published pursuant to sections 2002 and 4005 of RCRA. The commenters 
suggested that the final rule adopt a similar approach by defining a 
``state permit program'' and allowing a state permit program that met 
the definition to approve compliance with a specified regulatory 
requirement, e.g., landfill design. The commenter suggested the 
following definition: ``state permit program means a permit program 
implemented by a state agency that adopts and implements the minimum 
requirements for the disposal of coal combustion residuals outlined in 
this final rule.'' The commenter claimed that such an approach should 
not affect enforcement through citizen suits under RCRA section 7002 or 
by EPA under RCRA section 7003. Taking such an approach, commenters 
reasoned, would allow states to utilize their own enforcement authority 
and not rely upon the citizen suit authority under RCRA section 7002. 
Furthermore, allowing states to consider alternative approaches to the 
technical standards may give states an incentive to adopt the minimum 
requirements of the final federal rule into their state permit 
programs.
    As noted, many commenters suggested that EPA rely on the same 
combination of RCRA statutory authorities, i.e., RCRA sections 4010(c) 
and 4005(c), to establish controls for CCR units that it employed in 
promulgating federally enforceable subtitle D rules for MSWLFs and for 
non-MSWLFs that receive household

[[Page 21332]]

hazardous waste and small quantity generator waste under 40 CFR parts 
257 and 258. RCRA sections 4010(c) and 4005(c), the commenters 
reasoned, provides EPA that authority because non-hazardous waste CCR 
disposal facilities have the potential to receive household wastes or 
conditionally exempt small quantity generator waste, whether or not 
such waste is actually received at the CCR disposal facility. 
Commenters contended that the combination of these two provisions could 
enable EPA to promulgate non-hazardous waste rules for CCR that could 
be directly administered through state permitting programs and backed 
up by direct EPA enforcement powers in those states that fail to 
adequately implement the federal rules. Such an approach, commenters 
concluded provides the Agency with the enforcement authority it desires 
under a subtitle D regulatory program, while enabling states to have a 
prominent role in the administration of any subtitle D rules, and 
preventing the duplication of potentially conflicting federal and state 
controls.
    Finally, some commenters encouraged EPA to request from Congress 
the statutory authority necessary to propose non-hazardous regulations 
under subtitle D that could be implemented by the states and provide 
federal enforceability (similar to RCRA's part 258 requirements for 
MSWLFs). Commenters argued that states should be allowed to enforce 
compliance through a traditional permitting system, and that solid 
waste operating permits are critical to ensuring coal ash disposal 
facilities design, construct, operate and close their waste facilities 
safely. Commenters argued that permits are important because they can 
dictate the use of specific operating practices and control 
technologies that may be essential for minimizing releases. Permits 
also provide an important enforcement vehicle, as well as a process by 
which the public can be informed and participate in the siting, 
operation and closure of the waste disposal unit.
    While the Agency appreciates commenters' attempts to craft 
alternative approaches to address the limitations in the proposed self-
implementing subtitle D option, EPA has not ``chosen'' to design 
standards under subtitle D that are self-implementing. The sections of 
RCRA that are currently applicable to CCR--sections 1008(a), 4004(a), 
and 4005(a)--only authorize the Agency to establish minimum national 
criteria that apply to ``facilities.''
    As previously discussed, these provisions do not authorize EPA to 
require that facilities obtain a permit from EPA or a state. The fact 
that section 4004(a) does not contain any provision that either 
expressly requires a permit to manage waste, such as in section 3005, 
or that requires states to adopt a permit program, such as in section 
4004(c)(1), provides strong evidence that Congress did not authorize 
EPA to impose such a requirement on facilities managing solid waste. 
Compare 42 U.S.C. 6925(a), 6944(a), and 6945(c)(1). This is further 
confirmed by the fact that Congress thought it necessary to expressly 
add provisions to require state permit programs in 4010(c) and 4005(c). 
And the fact that the HSWA provisions are limited to two specifically 
enumerated types of units provides further evidence that Congress 
intended to authorize EPA to require permits only for these units.
    The restriction that the criteria apply only to ``facilities'' also 
means that EPA cannot establish any requirements on states or state 
programs, either directly or indirectly. This means, for example, that 
EPA cannot adopt a regulation that restricts certain provisions to 
those ``state permit programs'' that meet EPA requirements, as one 
commenter suggested, since this would indirectly regulate state 
programs--leaving aside that EPA never proposed anything of the sort. 
This also means that EPA cannot require a facility to obtain state 
approval, as this not only presupposes the existence of a state permit 
program, but also that the state will approve the facility action on 
the basis of EPA's criteria. EPA cannot condition a facility's 
compliance on actions beyond its control.
    However, these provisions restrict EPA's authority only. The 
legislation is clear that these are minimum requirements only, and 
without preemptive effect; states may therefore impose more stringent 
requirements, including the requirement that CCR facilities obtain a 
permit. This is also wholly consistent with longstanding EPA 
interpretations. See 44 FR 53438, 53439 (September 13, 1979) (``the 
standards established in the criteria constitute minimum requirements. 
These criteria do not preempt other state and federal requirements. 
Nothing in the Act precludes the imposition of additional obligations 
under authority of other laws on parties engaged in solid waste 
disposal.''); see also 44 FR 45066 (July 31, 1979) (``EPA establishes 
only `minimum' requirements under this portion of the Act which should 
not prevent States from developing broader programs or stricter 
standards under authority of State law.''). States may also incorporate 
the federal requirements into state law--whether through revisions to 
existing legislation or regulation, or through incorporating them into 
any permits issued to CCR facilities. Such an approach would also 
resolve commenters' concerns about the potential for ``parallel and 
redundant regulatory programs.''
    While subtitle C and 4005(c) provide for state oversight on rule 
implementation and allow approved state requirements to operate in lieu 
of federal criteria, the Agency lacks the authority to do so under the 
subsections of RCRA currently applicable to CCR. The provisions 
applicable to solid waste--sections 1008(a)(3), 4003, 4004(a) and 
4005(a)--establish a regulatory structure that differs in key respects 
from those established under subtitle C and for MSWLFs under section 
4005(c). Under subtitle C and section 4005(c), Congress required EPA to 
establish federal criteria that will serve as national minimum 
standards, which is comparable to the authority under section 4004(a). 
But subtitle C and section 4005(c) also include detailed provisions 
governing both the state implementation of those requirements and the 
relationship between the federal requirements and the state programs 
that implement them. No comparable provisions appear in either section 
4004(a) or section 4003, which governs the approval of state SWMPs. And 
the consequences of these omissions are significant.
    Subtitle C of RCRA contains several provisions that establish the 
relationship between the federal program and state requirements; these 
include provisions authorizing EPA to approve state programs and to 
retain a direct role in the implementation of the federal minimum 
requirements, whether through continued oversight of state 
implementation or direct implementation of the regulations. See, 42 
U.S.C. 6926, 6928(a)(2), and 6929. For purposes of this issue, the most 
critical of these is the explicit direction in section 3006 that 
authorized state programs ``operate in lieu of the Federal program.'' 
42 U.S.C. 6926(b), (c)(1). See also 42 U.S.C. 6929 (prohibiting the 
adoption of less stringent state requirements than those in EPA 
regulations, and authorizing states to establish more stringent 
requirements).
    The provisions for MSWLFs under section 4005(c) are less detailed, 
but establish a similar regulatory structure. Section 4005(c)(1) 
expressly directs the states to ``adopt and implement a permit program 
or other system of prior approval and conditions,'' for covered

[[Page 21333]]

facilities in order to implement federal requirements established for 
such facilities. 42 U.S.C. 6945(c)(1). The statute directs EPA to 
determine the adequacy of such programs, and directs EPA to enforce the 
federal requirements in states that have not adopted an adequate 
program. 42 U.S.C. 6945(c)(1)(C), (2). While less detailed than the 
provisions under subtitle C, section 4005(c) establishes a system that 
is equally predicated on mandated implementation by a state regulatory 
authority of the federal requirements, rather than the potential 
coexistence of two separate regulatory systems.
    The absence of any similar provisions in the ``solid waste'' 
provisions of subtitle D demonstrates that Congress intended to create 
a different regulatory structure. EPA's role under sections 1008(a)(3) 
and 4004(a) is to establish minimum criteria to determine which 
facilities ``shall be classified as sanitary landfills and which shall 
be classified as open dumps,'' and to encourage states to use the 
criteria as a part of their solid waste management planning. Under this 
regulatory structure, Congress intended that the federal requirements 
apply directly to facilities and operate independent of state 
involvement, unless the state chooses to do otherwise. The ability to 
approve state SWMPs under section 4003 does not alter this 
relationship. Indeed, the fact that Congress thought it necessary to 
revise section 4005 to include the specific provisions in subsection 
(c) confirms that Congress did not believe such authority already 
existed under sections 4003 and 4004.
    Approval of a state's SWMP pursuant to section 4003 qualifies the 
state to receive federal funds (no longer available) and authorizes the 
state to issue compliance schedules; but unlike under section 3006 or 
4005(c), an authorized plan does not affect the federal minimum 
standards themselves, or authorize states to do so. Section 4003 
contains nothing that explicitly or implicitly authorizes state 
requirements to operate ``in lieu of'' the federal requirement as a 
consequence of EPA approval of the state plan. The closest analogue is 
that states with an approved plan may establish a ``timetable or 
schedule'' to bring existing open dumps into compliance with the 
federal requirements; but notably, Congress only authorized the state 
to modify the timeframes by which such facilities must be in 
compliance, not the substantive requirements themselves. 42 U.S.C. 
6945(a).
    The combination of this regulatory structure and the need to 
demonstrate that the final rule achieves section 4004(a)'s 
protectiveness standard based on the record at the time the rule is 
promulgated also effectively limits EPA's ability to establish the kind 
of regulatory provisions commenters have requested (i.e., establish an 
alternative that allows a state permit program to approve a less 
stringent technical requirement based on site specific conditions). 
Because as discussed in Unit IV of this document, EPA is currently 
unable to reach a conclusion regarding the adequacy of state programs, 
EPA cannot demonstrate that such an alternative would meet the section 
4004(a) standard. And in the absence of a mandatory mechanism for 
subsequent public involvement and review, which would create decisions 
with their own record, subject to judicial review in their own right, 
the lack of such information is dispositive.
    With respect to the proposal to rely on RCRA sections 4010(c) and 
4005(c) authorities, EPA also disagrees that this is a viable option. 
As the comment appears to acknowledge, construing sections 4010(c) and 
4005(c) to apply to CCR units on the basis that they could potentially 
receive conditionally-exempt small quantity generator waste is 
inconsistent with EPA's longstanding interpretation of those sections. 
EPA directly addressed this issue nearly 20 years ago in the preamble 
for EPA's final rules at 40 CFR part 257, subpart B. In that discussion 
which we summarize in the next several paragraphs, EPA explained that 
the proposed rule was written to provide that only those non-municipal 
non-hazardous waste disposal units which meet the requirements in 
Sec. Sec.  257.5 through 257.30 ``may receive'' CESQG waste, as 
required by RCRA section 4010(c). Any non-municipal non-hazardous waste 
disposal unit that did not meet the proposed requirements may not 
receive CESQG hazardous wastes. The proposal was written to apply to 
non-municipal non-hazardous waste disposal units that receive CESQG 
waste for storage, treatment, or disposal, including such units as 
surface impoundments, landfills, land application units and waste 
piles. The regulatory definition of the term ``disposal'' cover all 
placement of wastes on the land. See 40 CFR 257.2.
    EPA further noted that several commenters addressed the Agency's 
interpretation of the statutory language ``may receive.'' One commenter 
supported the Agency's decision to limit the proposed regulatory 
requirements to only those non-municipal non-hazardous waste disposal 
units that receive CESQG wastes. Another commenter, however, stated 
that a closer reading of section 4010(c) reveals that Congress was not 
only concerned about modifying the criteria for ``facilities that may 
receive hazardous household wastes or hazardous wastes from small 
quantity generators . . .'' but also for ``facilities potentially 
receiving such wastes.'' According to the commenter, the ``may 
receive'' clause of the first sentence in section 4010(c) merely refers 
to whether a facility may legally receive CESQG waste for disposal. The 
``potentially receiving such wastes'' clause of the third sentence of 
Section 4010(c) refers to the actual potential for such facilities to 
receive CESQG wastes. The potential for CESQG waste to be disposed of 
at many types of industrial D landfills is high even with the proposed 
prohibition under Sec.  261.5. It is the ``potentially receiving'' 
clause that specifically commands the Agency to promulgate provisions 
for all industrial facilities that could potentially receive CESQG 
wastes.
    EPA disagreed with the commenter's interpretation of the statutory 
language in RCRA section 4010(c). More specifically, for a number of 
reasons, the Agency did not believe that the statutory language cited 
by the commenter evidenced congressional intent that the revised 
criteria promulgated in the rule should address disposal of solid waste 
in all industrial disposal facilities. First, EPA believed that the 
commenter erred by focusing only on the ``facilities potentially 
receiving'' language in the last sentence of section 4010(c). If one 
reviews this language together with the statutory language in RCRA 
section 4010(a), it is clear that Congress did not intend for the 
revised criteria being promulgated in this rule to apply to all 
industrial landfills.
    RCRA section 4010(a) required EPA to conduct a study of the then 
existing guidelines and criteria issued under RCRA sections 1008 and 
4004 which were applicable to ``solid waste management and disposal 
facilities, including, but not limited to landfills and surface 
impoundments.'' 42 U.S.C. 6949a(a). This statutory language does indeed 
suggest that EPA was to study a wide range of solid waste disposal 
facilities, including industrial landfills. (As the commenter stated, 
because the information on industrial disposal facilities was quite 
limited, EPA's report to Congress did focus on municipal landfills.)
    However, the statutory language in section 4010(c) directing EPA to 
promulgate a rule revising the criteria in 40 CFR part 257 limits the 
rule's applicability only to those facilities which may receive 
hazardous

[[Page 21334]]

household waste or small quantity generator waste. 42 U.S.C. 6949a(c). 
If Congress had intended the revised criteria under section 4010(c) to 
apply to all solid waste disposal facilities, including industrial 
landfills and surface impoundments, it clearly could have done so by 
enacting language similar to that already used in section 4010(a).
    Secondly, the legislative history of RCRA section 4010 suggests 
that Congress expressly rejected a provision that would have required 
rules to be promulgated under section 4010(c) to apply to the entire 
universe of RCRA subtitle D solid waste disposal facilities. Indeed, 
the House version of section 4010 would have required EPA to promulgate 
revised guidelines and criteria such that they would be applicable to 
all ``solid waste management and disposal facilities, including, but 
not limited to landfills and surface impoundments. . . .'' H.R. 2867, 
section 30, 98th Cong., 1st Sess. (as introduced in the Senate on 
November 9, 1983). However, the Conference Committee instead adopted a 
Senate amendment which limited the scope of the revised criteria to 
those facilities that may receive hazardous household waste or small 
quantity generator waste. H. Rept. No. 98-1133, 98th Cong., 2d Sess., 
at 116-117.
    Another indication that RCRA section 4010(c) was not intended to 
cover the entire universe of solid waste disposal facilities is the 
fact that subsequent to the enactment of section 4010(c) (as part of 
the Hazardous and Solid Waste Amendments in 1984), a number of bills 
were introduced in Congress which would have either authorized or 
required EPA to issue additional regulations that would address all 
disposal facilities receiving industrial waste as opposed to addressing 
those which may receive CESQG waste as stated in section 4010(c). See, 
e.g., H.R. 3735, ``Waste Materials Management Act of 1989,'' section 
324 (would have required EPA to promulgate standards for the management 
of industrial solid waste) (Luken Bill); S. 1113, ``Waste Minimization 
and Control Act of 1989,'' section 204 (would have required EPA to 
promulgate requirements for facilities that manage different types of 
industrial waste) (Baucus Bill). Neither of these provisions (although 
neither was enacted) would have been necessary if RCRA section 4010(c) 
required EPA to promulgate revised criteria for all types of industrial 
disposal facilities. (See 61 FR 34252, 34254-55 (July 1, 1996).)
    The commenter on the proposed CCR rule makes essentially the same 
argument based on the same language in 4010(c) that EPA rejected in the 
1996 rule. The commenter provided no legal analysis that contravenes 
the basis for EPA's interpretation of subtitle D. EPA thus declines to 
reopen or reconsider this interpretative question. EPA also notes that 
in any case, information in its record for this rulemaking indicates 
that CCR landfills or surface impoundments do not actually or 
potentially receive CESQG wastes.
    Nevertheless, EPA recognizes that this regulatory structure gives 
rise to legitimate concerns about the potential for duplicative or 
conflicting state and federal regulatory systems. EPA has adopted 
measures to address these concerns within the confines of the 
regulatory structure that Congress established in subtitle D. First, 
EPA has made every effort to ensure that the final rule does not 
establish any requirements that truly conflict with existing state 
programs. To clarify, this does not mean that the requirements are 
necessarily the same, but rather that it is possible to comply with 
both federal and state requirements simultaneously. Or in other words, 
compliance with the more stringent standard--whether federal or state--
will ensure compliance with the less stringent. Based on the comments 
received, EPA is aware of no example of a situation in which truly 
conflicting requirements will exist. Second, as discussed, these 
regulations do not constrain or direct state action. States can impose 
more stringent or different requirements, such as requiring a permit. 
Nor does the regulation require the state to enforce the federal 
requirements; even with promulgation of the final rule, the decision to 
bring an action under section 7002 remains entirely within the state's 
discretion. Third, as discussed in greater detail in Unit IX of this 
document, EPA has developed a number of measures to clarify the 
relationship between an individual state program, or particular 
requirements, and the federal criteria. Specifically, for those states 
that choose to submit a revised SWMP that incorporates the federal 
criteria, EPA intends to rely on the existing processes in 40 CFR part 
256 relating to approval of SWMPs. EPA expects that approval of a state 
SWMP, while it cannot prevent a citizen group from filing a lawsuit, 
will carry substantial weight in any court proceeding charged with 
determining whether compliance with state requirements constitutes 
compliance with the federal criteria.

B. Enforceability of the Subtitle D Approach

    Numerous commenters raised concern that reliance on a RCRA citizen 
suit as the basic enforcement mechanism to address non-compliance with 
the CCR requirements presents environmental justice concerns. 
Commenters argued that as a practical matter, this self-implementing 
approach would result in unenforced regulations affecting neighborhoods 
where environmental, legal, and technical services are unavailable or 
difficult to obtain. Commenters stated that it would be highly 
unreasonable for EPA to place the burden of enforcement of the CCR 
regulations on citizens, arguing that it is EPA's duty to make sure 
federal regulations protecting human health and the environment are 
enforced fairly and effectively, and that enforcement by citizen suits 
puts an unacceptable burden on low income populations located near 
these facilities. Commenters contended that environmental justice 
communities were the least likely to mount a serious challenge to the 
industry because low income people are often less well-educated, have 
less access to computers and internet technology, are less 
knowledgeable of how to access and interpret environmental data, and 
are the least likely to have the resources for a time consuming legal 
battle. Commenters argued that given the high number of damage cases in 
this industry, it was clear that the industry cannot police itself and 
neither can state governments. For these reasons, commenters asserted 
that the regulations and the enforcement must come from the federal 
level.
    Conversely, other commenters were encouraged by the opportunity to 
enforce the rule through citizen suits, stating that it would result in 
very effective regulation since citizens have shown no reluctance to 
challenge companies that they believe are not responsibly following 
environmental regulations. Similarly, other commenters noted that other 
incentives existed to comply with the regulations, including the 
possibility of state and third party litigation (for both regulatory 
compliance and actual damages), and the requirements of investors, 
lenders, and insurers to demonstrate compliance with environmental 
requirements, i.e., investors and lenders typically condition capital 
investments and loans on environmental compliance. Commenters also 
noted that incentives to comply were created by environmental insurance 
policies, which ``invariably exclude damage claims arising from non-
compliance from covered events'' as well as typical corporate policies 
that call for

[[Page 21335]]

environmental compliance as a standard operating procedure.
    Other commenters focused on the role of the professional engineer 
in the self-implementing framework, arguing that EPA is requiring the 
certifying professional to inappropriately take on a quasi-regulatory 
and enforcement role which places the certifying professional at great 
risk of being subject to nuisance lawsuits from project opponents, 
creating a scenario where some professionals may decline to be involved 
in such reviews. Still other commenters argued with EPA's basic premise 
that the RCRA subtitle D program lacks federal enforceability. 
Commenters contended that EPA's concerns about the lack of direct 
federal enforcement authority failed to recognize the significant 
enforcement opportunities available under existing law, namely the 
``imminent and substantial endangerment authority'' under RCRA section 
7003 to take action against any CCR unit that posed a risk to human 
health and the environment, as well as, the imminent and substantial 
endangerment authorities under CERCLA, as well as other federal 
authorities, including the federal Clean Water Act, to address 
circumstances where a CCR unit posed a threat.
    EPA acknowledges that the lack of federal enforcement under 
Subtitle D presents challenges. However, as discussed above, issuing 
minimum national standards under the authority that is currently 
applicable to CCR (i.e., subtitle D) is significantly more protective 
than the current federal standards in part 257 that apply to these 
wastes. It is more consistent with EPA's obligations under RCRA to put 
in place the additional protections that, based on the information 
currently available, are needed to protect health and the environment. 
As part of those requirements, EPA has developed a number of provisions 
designed to facilitate citizens to enforce the rule pursuant to RCRA 
section 7002. Chief among these is the requirement to publicly post 
monitoring data, along with critical documentation of facility 
operations, so that the public will have access to the information to 
monitor activities at CCR disposal facilities. Moreover, as noted 
elsewhere, a state seeking EPA's approval for a State SWMP would be 
required to conduct a public comment process to avail itself of the 
benefits of an EPA's approval.
    EPA also agrees that the Agency retains the authority to bring an 
action under RCRA section 7003, as well as other statutes, when the 
facts support the necessary findings. However, an action under section 
7003 does not enforce the requirements of this rule. Certainly, EPA 
believes that the failure to comply with the requirements of the rule 
increases the probability that an imminent and substantial endangerment 
may arise, but the fact that a facility has not complied with one or 
more of the requirements of this rule does not per se establish that a 
section 7003 order is warranted.
    The Agency also acknowledges that the self-implementing frameworks 
could potentially place certifying professionals at risk for lawsuits; 
several of the performance standards in the proposed rule were adopted 
from part 258, which were designed to operate in the context of an 
approved state program, under the oversight of a state regulatory 
authority, rather than a purely private entity. In part due to this 
concern, the Agency has re-evaluated the performance standards 
throughout the final rule, and has revised them where necessary to 
ensure that the requirements are sufficiently objective and technically 
precise that a qualified professional engineer will be able to certify 
that they have been met.

C. Reliance on Certification by Independent Qualified Professional 
Engineers

    As previously discussed, the majority of commenters were highly 
skeptical of a regulatory approach that substituted state oversight 
with an owner or operator hiring a consultant or professional, i.e., an 
independent registered professional engineer or hydrologist, to certify 
compliance with a federal regulatory requirement and posting that 
information on an internet site. More specifically, commenters were 
concerned that relying almost entirely on professional certifications 
for ensuring regulatory compliance did not seem like a reliable way to 
provide for protection of human health and or the environment.
    As explained in Unit IV.A of this document, EPA is issuing national 
minimum criteria under subtitle D to put in place the technical 
requirements the Agency has determined are necessary to protect human 
health and the environment from the disposal of CCR in surface 
impoundments and landfills, while the Agency completes its Bevill 
Determination. EPA is relying on the certification in this context to 
partially compensate for one of the more significant limitations under 
the authorities currently applicable to CCR: The lack of any guaranteed 
regulatory oversight mechanism. However, EPA disagrees that the rules 
rely ``almost entirely'' on professional engineers to protect human 
health and the environment. The final rule relies on multiple 
mechanisms to ensure that the regulated community properly implements 
requirements in this rule. As one part of this multi-mechanism 
approach, owners or operators must obtain certifications by qualified 
individuals verifying that the technical provisions of the rule have 
been properly applied and met. However, a more significant component 
supporting EPA's determination that the technical requirements will 
achieve the level of protection required under section 4004(a) is the 
performance standards that the rules lay out. These standards impose 
specific technical requirements, and, even where they provide 
flexibility, will operate to significantly constrain the facility's 
activities and discretion. The certifications required by the rule 
supplement these technical requirements, and while they are important, 
they are not the sole mechanism ensuring regulatory compliance.
    The rule also contains a number of provisions requiring the owner 
or operator to document their compliance with the rule's technical 
requirements, and to post those documents on a publically available Web 
site in a timely and transparent manner. The rule also requires owners 
or operators to notify State Directors of numerous actions, including 
that certified demonstrations have been completed. This transparency 
will facilitate citizen and state oversight and overall enforcement of 
the requirements. Finally, the rule establishes specific timeframes by 
which these actions must occur, including timeframes by which 
facilities must document compliance with the various technical 
requirements in the rule. Timeframes have been established for: (1) 
Technical compliance demonstrations made by the owner or operator; (2) 
certifications made by a qualified professional engineer verifying the 
technical accuracy and veracity of the compliance demonstration; (3) 
notifications made to the State Director; (4) submittals (e.g., data, 
reports and other documentation) to the operating record; and (5) 
postings to the owner or operator's publicly accessible internet site. 
Further details pertaining to all of these requirements can be found in 
the Recordkeeping, Notification, and Posting of Information to the 
Internet section of the regulations published in this rule.
1. Changes to the Definition of Independent Registered Professional 
Engineer or Hydrologist
    EPA proposed to define ``independent registered professional 
engineer or

[[Page 21336]]

hydrologist'' to mean a scientist or engineer who is not an employee of 
the owner or operator of a CCR landfill or CCR surface impoundment, who 
has received a baccalaureate or post-graduate degree in the natural 
sciences or engineering, and who 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 judgment regarding the technical information for 
which a certification under this subpart is necessary.
    Many comments were received on the definition. Some commenters 
agreed with the proposed definition, but most commenters argued that 
significant changes were needed. These changes included removing the 
requirement that the engineer be ``independent,'' adding the word 
``qualified,'' and limiting the ability to make certifications to 
``licensed'' professional engineers. Still other commenters felt that 
EPA should broaden the qualifications beyond a professional engineer or 
hydrologist, to include geologists, hydrogeologists, groundwater 
scientists or ``other qualified environmental professionals'' among the 
individuals able to certify regulatory demonstrations.
    By far the issue receiving the most comment was whether the Agency 
should require a professional engineer to be ``independent.'' 
Commenters disagreed with EPA that the certification must be made by an 
independent registered professional engineer (i.e., not an employee of 
the owner or operator of the CCR unit). Commenters argued that most 
utilities employ a number of professional engineers that typically 
possess the most relevant experience and knowledge about the unit, and 
that company-employed engineers and hydrologists were in a much better 
technical position to certify technical provisions of the rule were 
being met. Furthermore, commenters asserted that these professionals 
would be subject to the same state registration and licensing 
requirements as those not employed by the facility and would have an 
equally strong incentive to maintain their licenses in good standing as 
those that are independent of the utility. These commenters also 
pointed to several EPA rulemakings in which EPA allowed ``qualified'' 
professional engineers to make the kind of certifications contemplated 
by this rulemaking, without requiring that they be ``independent.'' 
Commenters also contended that state licensing and registration 
programs help to ensure that all professionals exercise proper judgment 
or ``independence'' regarding the operation of CCR landfills and CCR 
surface impoundments. Similarly, commenters claimed that a professional 
engineer without the required expertise would refuse to make any 
certifications for which they were not qualified. Some commenters 
suggested that EPA provide some criteria requiring demonstrated 
experience and training. Commenters also took issue with the fact that 
the definition focused entirely on groundwater hydrology and failed to 
include training or experience in other areas that would also be 
necessary to effectively certify specific technical criteria of the 
rule (e.g., structural integrity, composite liner design).
    The definition EPA proposed for ``independent registered 
professional engineer or hydrologist,'' focused on three components 
that were intended to define the minimum qualifications necessary to 
independently verify that a specific technical standard was met and to 
provide sufficient objectivity to reduce the opportunity for abuse. 
These components were: (1) The individual was a scientist or engineer 
by academic training or education; (2) the individual was not an 
employee of the owner or operator of the CCR unit; and (3) the 
individual had sufficient training in groundwater hydrology or related 
fields. The proposed definition did not require the individual to be a 
licensed professional engineer or hydrologist; instead the Agency 
prohibited the individual providing the certification from being an 
employee of the owner or operator of the CCR unit, reasoning that this 
requirement would provide some degree of independent verification of 
facility practices.\37\ The Agency stated that the availability of 
meaningful independent verification was critical to EPA's ability to 
conclude that the performance standards laid out in the proposed rule 
would meet the RCRA section 4004 protectiveness standard.
---------------------------------------------------------------------------

    \37\ While the definition did not require the independent 
registered professional engineer or hydrologist to be licensed, the 
preamble did state that 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 of the CCR landfill or CCR surface 
impoundment, and that they operate under penalty of losing their 
license, implying that the professional was, in fact, licensed. This 
narrative and the title of independent registered professional 
engineer caused many commenters to assume that the certifiers indeed 
had to be licensed professional engineers. (See 75 FR 35194, June 
21, 2010.)
---------------------------------------------------------------------------

    In the course of developing this final rule, the Agency concluded 
that it needed to better define the connection between the technical 
requirements of the rule and the technical qualifications an individual 
must possess to certify the demonstrations being made by the owner or 
operator of the CCR unit. In doing so, the Agency looked for direction 
in the following rules, the ``Resource Conservation and Recovery Act 
(RCRA) Burden Reduction Initiative'' (71 FR 16826, April 4, 2006) and 
the ``Oil Pollution Prevention and Response; Non-Transportation-Related 
Onshore and Offshore Facilities rule (67 FR 47042, July 17, 2002). In 
both of these actions, the Agency had come to similar conclusions. 
First, that professional engineers, whether independent or employees of 
a facility, being professionals, will uphold the integrity of their 
profession and only certify documents that meet the prescribed 
regulatory requirements; and that the integrity of both the 
professional engineer and the professional oversight of boards 
licensing professional engineers are sufficient to prevent any abuses. 
(For an example see: 67 FR 47084, July 17, 2002.) And second, that in-
house professional engineers may be the persons most familiar with the 
design and operation of the facility and that a restriction on in-house 
professional certifications might place an undue and unnecessary 
financial burden on owners or operators of facilities by forcing them 
to hire an outside engineer.
    Reviewing these other regulatory actions and the Agency's rationale 
for making its decisions, has led the Agency to a similar conclusion 
with regard to this rule--that it is unnecessary to require the 
individual making certifications under this rule to be ``independent.'' 
Thus the final rule does not prohibit an employee of the facility from 
making the certification, provided they are a professional engineer 
that is licensed by a state licensing board. The personal liability of 
the professional engineer provides strong support for both the 
requirement that certifications must be performed by licensed 
professional engineers, and for removing the requirement that the 
engineer be ``independent.''
    While other commenters argued that the word ``independent'' should 
be retained because an independent review and certification avoids any 
potential of conflict of interest, the Agency is convinced that an 
employee of a facility, who is a qualified professional engineer and 
who has been licensed by a state licensing board would be no more 
likely to be biased than a qualified professional engineer who is not 
an employee of the owner or operator. Moreover, it is not clear that an 
in-house engineer faces a greater economic temptation than an 
independent

[[Page 21337]]

engineer seeking to cultivate an ongoing relationship with a client. 
EPA has concluded that the programs established by state licensing 
boards provide sufficient guarantees that a professional engineer, 
regardless of whether he/she is ``independent'' of the facility, will 
give a fair technical review.
    As an additional protection, the Agency has re-evaluated the 
performance standards throughout the final rule to ensure that the 
requirements are sufficiently objective and technically precise that a 
qualified professional engineer will be able to certify that they have 
been met.
    The Agency agrees with concerns that a professional engineer may 
not be qualified to address all the varied aspects of CCR landfill and 
CCR surface impoundment design, and has amended the definition to 
clarify and strengthen the qualifications of the individual authorized 
to certify the technical demonstrations under the rule. In the proposed 
rule, the Agency did not require an independent registered professional 
engineer to be licensed, only that they be an engineer or hydrologist 
who had received a baccalaureate or post graduate degree in the natural 
sciences with training and experience in groundwater hydrology or a 
related field. While the term ``independent registered professional 
engineer or hydrologist'' conveyed to some commenters that the 
individual was in fact ``licensed,'' the definition in the proposal did 
not require it. Furthermore, as noted by commenters, the proposed 
definition focused primarily on hydrogeology expertise and did not 
include training and experience qualifications necessary to accurately 
certify some of the requirements being promulgated in the rule, e.g., 
landfill and surface impoundment design and construction, structural 
stability assessments, analysis of unstable areas. In reviewing this 
proposed requirement, the Agency has determined that specifying exact 
qualifications and or experience for the professional engineer is 
neither necessary nor practical, given the range of technical 
specifications that will require certification. EPA has therefore 
adopted a more succinct requirement focused on the professional 
engineer's qualifications to perform the task or certification.
    In making this change, the Agency was again strongly influenced by 
the ``Resource Conservation and Recovery Act (RCRA) Burden Reduction 
Initiative'' rule. (See 71 FR 16826, April 4, 2006.) In that rule, EPA 
amended the majority of RCRA provisions requiring the certification of 
an ``independent, qualified, registered, professional engineer'' to 
substitute the phrase, a ``qualified professional engineer,'' reasoning 
that a requirement for a qualified professional engineer maintains the 
most important components of any certification requirement: (1) That 
the engineer be qualified to perform the task based on training and 
experience; and (2) that she or he be a professional engineer licensed 
to practice engineering under the title Professional Engineer which 
requires following a code of ethics with the potential of losing his/
her license for negligence (see 71 FR 16868.)
    In the ``Burden Reduction Rule'' the Agency concluded that a 
professional engineer is able to give fair and technical review because 
of the oversight programs established by the state licensing boards 
that will subject the professional engineer to penalties, including the 
loss of license and potential fines if certifications are provided when 
the facts do not warrant it. In fact, this personal liability of the 
professional engineer is one of the primary reasons that commenters to 
the ``Burden Reduction Rule'' supported the idea that RCRA 
certifications should only be done by licensed professional engineers 
(See 71 FR 16868.) Upon further analysis and reflection, the Agency 
sees no reason to deviate from the position EPA held in that rule. 
Despite some concerns raised by commenters that problems could occur if 
an owner or operator hires an engineering firm that is small, 
inexperienced, or operating outside of their past professional 
practice, the Agency continues to believe that with the protections 
afforded by the specific performance standards in this rule and the 
standards and ethics to which a qualified professional engineer is 
subject, situations in which an unqualified or un-licensed engineer 
certifies a technical demonstration will be avoided. Furthermore, it is 
important to reiterate that state licensing boards can investigate 
complaints of negligence or incompetence on the part of professional 
engineers, and may impose fines and other disciplinary actions, such as 
cease-and-desist orders or license revocation. (See 71 FR 16868.) In 
light of the third party oversight provided by the state licensing 
boards in combination with the numerous recordkeeping and recording 
requirements established in this rule, the Agency is confident that 
abuses of the certification requirements will be minimal and that human 
health and the environment will be protected.
    The Agency wants to make it clear that qualified professional 
engineers can utilize a qualified team of professionals in performing 
the analyses that underlie these certifications. In most instances, EPA 
expects that the basis for certification by a qualified professional 
engineer will be the result of a team of professionals (e.g., 
geologists, hydrologists, scientists and engineers) who have 
collectively worked together in order to provide the data and analyses 
necessary for the professional engineer to certify the specific 
demonstration.
    The Agency is convinced that the change to the certification 
requirements to allow the use of in-house expertise will not compromise 
environmental safety. Professional engineers employed by a facility are 
more familiar with the facility's particular situation and are in a 
position to provide more on-site review and oversight of the activity 
being certified. To this end, the Agency is also requiring that the 
qualified professional engineer be licensed in the state in which the 
CCR unit is located. The Agency has made this decision for a number of 
reasons, but primarily because state licensing boards can provide the 
necessary oversight on the actions of the professional engineer and 
investigate complaints of negligence or incompetence as well as impose 
fines and other disciplinary actions such as cease-and-desist orders or 
license revocation. Oversight may not be as rigorous if the 
professional engineer is operating under a license issued from another 
state.
    Finally, the Agency disagrees with comments that professional 
geologists or geoscientists should be added to the list of those 
professionals that have expertise and authority to certify compliance 
with certain RCRA subtitle D regulatory requirements. In developing 
this final rule, the Agency has re-considered the qualifications 
necessary to certify compliance with the technical requirements of the 
rule and is limiting compliance certifications to qualified 
professional engineers only. While some environmental professionals, 
e.g., hydrologists, geologists may be qualified to make certain 
certifications, EPA is not convinced that hydrologists or geologists 
licensed by a state are held to the same standards as a professional 
engineer licensed by a state licensing board. For example, it is 
unclear that hydrologists or geologists are subject to the rigorous 
testing required by professional engineers or that state licensing 
boards can investigate complaints of negligence or incompetence. 
Further, professional engineers have licensing boards in all 50 states, 
a standard not achieved by other

[[Page 21338]]

professional disciplines. Consequently, hydrologists, geologists, or 
other professionals may only perform analyses that underlie the 
certification, but it is the responsibility of a qualified professional 
engineer to make the actual certification.

D. State and Public Notifications of Certifications

    To address concerns about the absence of adequate regulatory 
oversight under subtitle D, EPA proposed to require state and public 
notifications of the third party certifications, as well as other 
information documenting the decisions made or actions taken by the 
owner or operator to comply with the technical criteria in the rule. As 
stated in the proposal and reiterated here, the Agency cannot conclude 
that the regulations promulgated in this rule will ensure there is no 
reasonable probability of adverse effects on health or the environment 
unless there is a mechanism for states and citizens, as the entities 
responsible for enforcing the rule, to effectively monitor or oversee 
its implementation. Mandated documentation and transparency of the 
owner or operator's actions to comply with the rule provides this 
mechanism, and will help to minimize the potential for abuse. The 
proposal specified that the documentation of how the various technical 
standards had been met were to be placed in the facility's operating 
record, along with notification to the appropriate state authority. 
Additionally, EPA proposed to require the owner or operator to maintain 
a Web site available to the public that would also provide access to 
this documentation. EPA proposed that owners or operators post notices 
and relevant information on the internet site with a link clearly 
identified as being a link to notifications, reports, and 
demonstrations required under the regulations. While EPA recognized 
that the internet is currently the most widely accessible means for 
gathering and disseminating information, the Agency also solicited 
comments regarding alternative methods to provide notifications to the 
public and the states. The Agency also solicited comment on whether to 
require the establishment of a publicly accessible internet site to 
provide regulatory information to the public and the states, including 
whether there could be homeland security implications associated with 
internet posting of information, and whether the posting would 
duplicate information that is already available to the public through 
the state.
    In response to most of these proposals, the Agency received little 
comment. Significant comment, however, was received on the publicly 
accessible internet site. Commenters argued that absent specific 
statutory authorization, it was inappropriate for EPA to delegate a 
regulatory oversight function to the regulated community by requiring 
the creation of a Web site and posting of regulatory compliance 
information. Commenters identified at least three substantial problems 
associated with ``outsourcing information management responsibilities'' 
to CCR facilities. First, commenters argued that EPA lacked the 
authority to impose such a requirement. Specifically, the commenters 
alleged that no statute authorizes EPA to demand that private parties 
act as an information clearinghouse for information pertaining to EPA's 
regulatory functions, either generally or in the specific context of 
CCR. To the contrary, the commenters argued, public information access 
statutes, such as the Freedom of Information Act are predicated on an 
assumption that information held by the government is presumptively 
public, while information held by a private entity presumptively is 
not.
    Second, some commenters were concerned that facilities would not 
post information the facility deems to be confidential (e.g., the 
structural stability of ash pond impoundments) and by attempting to 
outsource the information management role to industry, EPA effectively 
allows industry to make the initial determination as to confidentiality 
and places the burden on citizens and EPA to take action to compel 
disclosure.
    Third, commenters were concerned that citizen groups would not 
accept an electric utility's self-reported information, regardless of 
the amount of effort the facility exerts to ensure the accuracy of the 
information, without a regulatory agency acting as the intermediary or 
providing some degree of oversight (e.g., EPA's Toxic Release 
Inventory, EPA's Biennial Report of hazardous waste facilities). By 
requiring citizen groups to obtain their information from industry 
instead of a regulator, the commenters argued that EPA is inviting 
conflict as to the adequacy of data and the sufficiency of the 
utilities' responses to citizen groups' requests for clarification or 
additional information. The fact that the industry has provided 
information to a federal agency, subject to criminal penalties for 
providing false information, provides a useful public assurance of the 
integrity of the information.
    Other commenters stated that the proposed requirement to maintain a 
Web site was excessive, and generated a regulatory burden upon 
companies that serves no useful function. Commenters urged that the 
same purpose could be served simply through making the certification of 
the registered professional engineer available on the Web site. Other 
commenters argued that internet posting of information on a surface 
impoundment's construction raised homeland security issues. These 
commenters alleged that the information ``can be extremely sensitive 
and may contain information that could be used by certain individuals 
with an intent to destroy a dam (e.g., engineering information on the 
structure's foundation, detailed information on physical and 
engineering properties, the basis for the structure hazard 
classification, slope stability information, etc.).''
    Finally, some commenters offered an alternative to the requirement 
to establish and maintain a publicly accessible internet site. Under 
this alternative the information would be included in the owner or 
operator's operating record only, and persons with ``legitimate 
interests in reviewing these data'' could make a written request to the 
owner or operator or the permitting authority to obtain the 
information. The commenters alleged that this would also allow the 
owner, operator, and federal and state authorities to know the names 
and identities of all organizations requesting information on the 
facility, which would help protect against the misuse of these data.
    EPA disagrees that RCRA section 4004(a) does not authorize EPA to 
require facilities to disclose all of the information required under 
these final rule provisions. Section 4004(a) delegates broad authority 
to EPA to establish criteria governing facilities' management of solid 
waste, requiring only that such criteria ensure that there will be no 
reasonable probability of adverse effects on health or the environment 
from the disposal of solid waste. The statute imposes no limits on the 
actions EPA may require facilities to perform to achieve that level of 
protection. Moreover, unlike other statutes, e.g., the Toxic Substances 
Control Act, or the Federal Insecticide, Rodenticide and Fungicide Act, 
RCRA contains neither provisions that grant facilities the right to 
withhold regulatory compliance information from the public, nor 
provisions that establish any reasonable expectation that such 
information will be kept confidential. To the contrary, section 7004 
explicitly provides that ``[p]ublic participation in

[[Page 21339]]

the . . . implementation, and enforcement of any regulation under this 
chapter shall be provided for, encouraged, and assisted by the 
Administrator.'' 42 U.S.C. 6974(b). And in fact, this kind of 
information would routinely be publically available under the 
permitting process for hazardous waste facilities. Accordingly, RCRA 
provides more than ample authority to support these requirements.
    As repeatedly discussed throughout this preamble, under section 
4004(a) EPA must be able to demonstrate, based on the record available 
at the time the rule is promulgated that the final rule provisions will 
achieve the statutory standard. EPA explained in the proposal that a 
key component of EPA's support for determining that the rule achieves 
the statutory standard is the existence of a mechanism for states and 
citizens to monitor the situation, such as when groundwater monitoring 
shows evidence of potential contamination, so that they can determine 
when intervention is appropriate. The existence of effective oversight 
measures provides critical support for the statutory finding, 
particularly with respect to some of the more flexible alternatives EPA 
has adopted in certain of the technical standards in response to 
commenters' requests for greater flexibility. These ``transparency'' 
requirements serve as a key component by ensuring that the entities 
primarily responsible for enforcing the requirements have access to the 
information necessary to determine whether enforcement is warranted. 
Unlike a federal or state regulatory authority, private citizens cannot 
access a private facility to conduct inspections. While EPA encourages 
states to adopt and implement a CCR regulatory program, and seek EPA's 
approval of it via a state SWMP, EPA cannot require it. The final rule 
therefore must establish oversight mechanisms that will function 
effectively even in the absence of a state regulatory authority.
    Such notifications will also reduce the incentives for owners or 
operators to abuse the rule's self-implementing requirements, and can 
improve compliance. Indeed, the public disclosure of information is an 
increasingly common and important regulatory tool, as evidenced by the 
2010 guidance issued by the Office of Management and Budget (OMB), with 
principles to assist agencies in using information disclosure to 
achieve regulatory objectives.
    Thus, even if the commenters were correct that there exists a 
general ``presumption'' that information held by private entities need 
not be made publically available, that presumption can be, and has 
been, effectively rebutted by the facts at hand.
    None of the alternatives offered by the commenters would fulfill 
these same objectives. For example, simply making the certification of 
the qualified professional engineer available on the Web site without 
the underlying support information fails to provide the same incentives 
because no one could evaluate the accuracy of that certification. This 
alternative could also present the same concerns raised in comments on 
other sections of the rule, i.e., that such a requirement could place 
the engineer at great risk of being subject to lawsuits. Requiring 
persons with ``legitimate interests in reviewing these data'' to 
request the data from the owner or operator also fails to provide an 
effective guarantee, as facilities that have failed to comply will have 
a strong incentive to withhold information documenting their non-
compliance, however ``legitimate'' the request. And as noted, the 
absence of a guaranteed state permitting program means that requiring 
citizens to request information from such entities is also not a viable 
alternative. Given the absence of a guaranteed regulatory authority, 
EPA also disagrees that posting such information on a company internet 
site is necessarily duplicative, particularly in those states that have 
no regulatory program for controlling CCR. In addition, state 
requirements, whether pursuant to permits or other regulatory 
mechanisms, may not necessarily correspond to the requirements of this 
rule.
    EPA acknowledges that parties may be suspicious of information 
self-reported by regulated entities. However, it is important to 
remember that facilities that provide information in compliance with 
these regulation remain subject to the penalties for providing false 
information under 18 U.S.C. 1001, even though the information will not 
be submitted to EPA. For example, the Tenth Circuit has held that 
federal jurisdiction lies under 18 U.S.C. 1001 when a defendant has 
submitted false information to a state delegated to enforce a federal 
environmental statute. United States v. Wright, 988 F.2d 1036 (10th 
Cir. 1993) (defendant submitted false monitoring reports required by 
the Safe Drinking Water Act to Oklahoma officials). This is consistent 
with rulings in other areas that the false statement need not be made 
directly to the federal government. United States v. Uni Oil Co., 646 
F.2d 946, 954-55 (9th Cir. 1981); see also United States v. Patullo, 
709 F.2d 1178, 1180 (7th Cir. 1983); United States v. Ross, 77 F.3d 
1525, 1544 (7th Cir. 1996) (``This court has repeatedly found the 
submission of a fraudulent statement to a private (or non-federal 
government) entity to be within the jurisdiction of a federal agency 
where the agency has given funding to the entity and fraudulent 
statements cause the entity to utilize the funds improperly.''). As 
commenters recognized, the potential for criminal penalties under 18 
U.S.C. 1001 provides a significant guarantee, as well as a strong 
incentive for compliance.
    EPA also disagrees with the comments raising concern about the 
homeland security implications of posting information on a CCR surface 
impoundment's construction, as it relates to structural stability. Much 
of the information relevant to an impoundment's structural stability is 
currently available through Google Earth or through EPA's Web site. For 
example, EPA's Web site currently provides access to all of the 
information from the responses to EPA's original 104(e) information 
requires and the information obtained through the CCR Assessment 
Program. This information can be accessed at the following pages: 
http://www.epa.gov/osw/nonhaz/industrial/special/fossil/surveys/index.htm, http://www.epa.gov/osw/nonhaz/industrial/special/fossil/surveys2/index.htm, and http://www.epa.gov/osw/nonhaz/industrial/special/fossil/ccrs-fs/index.htm. Moreover, the Department of Homeland 
Security has cleared both the internet posting of all of the 
information currently on EPA's Web site, as well as, in general, 
information on the design, hydraulic parameters, volume of contained 
liquids and solids, and hazard rating of all major CCR surface 
impoundments across the U.S.

VI. Development of the Final Rule--Technical Requirements

A. Applicability

    EPA proposed general provisions to identify those solid waste 
disposal units subject to the proposed RCRA subpart D requirements 
(i.e., CCR landfills and CCR surface impoundments as defined under 
proposed Sec.  257.40(b)). The applicability section also identified 
three of the existing subpart A criteria that would continue to apply 
to these facilities: Sec.  257.3-1 Floodplains, Sec.  257.3-2 
Endangered Species, and Sec.  257.3-3 Surface Water. Consistent with 
RCRA section 4004(c), EPA specified an effective date of 180 days after 
publication of the final rule.
    The Agency received numerous comments on this part of the rule. In

[[Page 21340]]

general, commenters were concerned with three specific areas. First, 
commenters requested additional clarification as to the specific 
sources of CCR that would be subject to the requirements of the rule, 
i.e., CCR generated by the electric utilities and independent power 
producers. Second, commenters requested clarification on the 
applicability of the proposed regulations to MSWLFs disposing of CCR 
and third, the definition and status of ``uniquely associated wastes.'' 
Uniquely associated wastes are addressed in Unit XIII of this preamble. 
EPA also received numerous comments regarding the proposal to apply the 
rule to ``inactive'' CCR surface impoundments that had not completed 
closure prior to the effective date of the rule.
    EPA is finalizing minimum national criteria that apply to owners 
and operators of new and existing CCR landfills and CCR surface 
impoundments, including any lateral expansions of these units that 
dispose, or otherwise conduct solid waste management of CCR generated 
from the combustion of coal at electric utilities and independent power 
producers. The rule applies only to CCR units at ``active'' electric 
utilities and independent power producers, i.e., those that generate 
electricity, regardless of the fuel currently used to produce 
electricity. However, disposal units at facilities that are 
``closed''--i.e., the entire facility has been permanently taken out of 
service and no longer produces electricity--are outside of the scope of 
this rule.
    Unless otherwise provided, the rule applies to CCR units located 
both on-site and off-site of the electric utility or independent power 
producer.
1. CCR Generated by Non-Utility Boilers
    The requirements of this rule do not apply to wastes, including fly 
ash, bottom ash, boiler slag, and FGD materials generated at facilities 
that are not part of the electric power sector or an independent power 
producer and that use coal as the fuel in non-utility boilers, such as 
manufacturing facilities, universities, and hospitals. Industries that 
primarily burn coal to generate power for their own purposes (i.e., 
non-utilities), also known as combined heat and power (CHP) plants, are 
primarily engaged in business activities, such as agriculture, mining, 
manufacturing, transportation, and education. The electricity that they 
generate is mainly for their own use, but any excess may be sold in the 
wholesale market. According to the Energy Information Administration 
(EIA), CHPs produced less than one percent of the total electricity 
generated from coal combustion in 2013 and, similarly, burned less than 
one percent of the total coal consumed for electricity generation or 
less than 5 million tons (http://www.eia.gov/electricity/data.cfm).
    EPA never proposed to include these wastes in the rule because EPA 
lacked critical data from these facilities that would allow us to 
address key Bevill criteria (see 75 FR 35165). These other industries, 
and the manufacturing industries in particular, generate other types of 
wastes which are likely to be mixed or co-managed with the CCR at least 
at some facilities. As a result, the chemical compositions of the co-
managed wastes are likely to be fundamentally different from the 
chemical composition of CCR generated by electric utilities or 
independent power producers. In addition, EPA noted that insufficient 
information was available on non-utility boilers burning coal to 
determine whether a regulatory flexibility analysis would be required 
under the Regulatory Flexibility Act, and to conduct one if it is 
necessary. Without such data, we were unable to fully assess CCR wastes 
from non-utility operations and indicated that we would decide on an 
appropriate course of action for these wastes after completing this 
rulemaking (see 75 FR 35129).
    Several commenters stated that EPA's decision to propose limiting 
the scope of the rule only to CCR generated by the electric power 
sector (electric utilities and independent power producers) was 
arbitrary. These commenters claimed that CCR generated by the electric 
power sector and CCR generated by non-utilities are generally 
comparable in physical and chemical composition and are typically 
managed similarly. As a result, these commenters suggested that EPA 
amend the applicability of the rule to subject all facilities that 
generate CCR to the same disposal requirements. EPA also received 
comments maintaining that important differences exist between CCR 
generated by electric power sector facilities and non-utility 
facilities, and that supported EPA's proposed decision to exclude CCR 
generated by non-utilities from the rule. Differences identified by the 
commenters included waste management issues (e.g., mixing and 
subsequent co-management of non-utility CCR and other industrial wastes 
generated by non-utilities), CCR generation rates, CCR management unit 
design, and CCR management unit operation. In response to our request 
for additional information, a few commenters provided either waste 
characterization data for non-utility CCR or information on alleged 
damage cases involving non-utility CCR.
    Based on the proposed rule, EPA cannot include these facilities in 
this final rule, even if the Agency had concluded that it had received 
the necessary information from commenters. EPA specifically stated its 
intention to exclude them, and clearly stated that it had not assessed 
the operations. (See 75 FR 35166.) The Agency provided no indication of 
any intention to include such facilities, and did not solicit comment 
on such an option. Moreover, under the Administrative Procedure Act, 
the public must be given the opportunity to comment on not only the 
information that would support such an action, but also EPA's 
evaluation of that information, and the reasoning behind the Agency's 
decision. And with respect to this subset of facilities, no such 
opportunity has been presented. EPA will consider the information 
provided by commenters at a future point, and will determine whether 
the information is sufficient to address key Bevill criteria and to 
decide on the appropriate regulatory scheme for disposal of CCR 
generated by non-utilities. Accordingly, this rule does not apply to 
owners and operators of landfills and surface impoundments in which CCR 
are disposed that were generated by non-utility boilers burning coal.
2. CCR Generated Primarily From the Combustion of Fuels Other Than Coal
    These requirements also do not apply to fly ash, bottom ash, boiler 
slag, and flue gas desulfurization materials, generated primarily from 
the combustion of fuels (including other fossil fuels) other than coal, 
for the purpose of generating electricity unless the coal comprises 
more than fifty percent (50%) of the fuel burned on a total heat input 
or mass input basis, whichever results in the greater mass feed rate of 
coal (see Sec.  266.112). Fuel mixtures that contain less than 50% coal 
are not considered to be CCR, but other fossil fuel wastes. Other 
fossil fuels that are typically co-combusted with coal are oil and 
natural gas. In the May 22, 2000 Regulatory Determination, EPA 
determined that it is not appropriate to establish national regulations 
applicable to oil combustion wastes (OCW) because: (1) We found in most 
cases that OCW, whether managed alone or co-managed, are rarely 
characteristically hazardous; (2) we have not identified any beneficial 
uses that are likely to present significant risks to human health or 
the environment; (3) we identified no significant ecological risks 
posed by

[[Page 21341]]

land disposal of OCW; (4) we identified only one documented damage case 
involving OCW in combination with coal combustion wastes, and it did 
not affect human receptors; and (5) except for two unlined surface 
impoundments, we have not identified any significant risks to human 
health and the environment associated with any waste management 
practices. Similarly, EPA determined that regulating natural gas 
combustion wastes is not warranted because the burning of natural gas 
produces virtually no solid waste. Therefore, the Agency has determined 
that regulations for wastes generated primarily from the combustion of 
fuels (including other fossil fuels) other than coal are not warranted 
unless the fuel mixture consists primarily of coal.
3. Placement of CCR in Minefilling Operations
    Consistent with the approach in the proposed rule, this rule does 
not apply to CCR placed in active or abandoned underground or surface 
coal mines. The U. S. Department of Interior (DOI) and EPA will address 
the management of CCR in minefills in a separate regulatory action(s). 
EPA will work with the OSM to develop effective federal regulations to 
ensure that the placement of coal combustion residuals in minefill 
operations is adequately controlled. In doing so, EPA and OSM will 
consider the recommendations of the National Research Council (NRC), 
which, at the direction of Congress, studied the health, safety, and 
environmental risks associated with the placement of CCR in active and 
abandoned coal mines in all major U.S. coal basins. The NRC published 
its findings on March 1, 2006, in a report entitled ``Managing Coal 
Combustion Residues (CCR) in Mines,'' which is available at http://books.nap.edu/openbook.php?isbn=0309100496.
    The report concluded that the ``placement of CCR in mines as part 
of coal mine reclamation may be an appropriate option for the disposal 
of this material. In such situations, however, an integrated process of 
CCR characterization, site characterization, management and engineering 
design of placement activities, and design and implementation of 
monitoring is required to reduce the risk of contamination moving from 
the mine site to the ambient environment.'' The NRC report recommended 
that enforceable federal standards be established for the disposal of 
CCR in minefills to ensure that states have specific authority and that 
states implement adequate safeguards. The NRC Committee on Mine 
Placement of Coal Combustion Wastes also stated that OSM and its SMCRA 
state partners should take the lead in developing new national 
standards for CCR use in mines because the framework is in place to 
deal with mine-related issues. Consistent with the recommendations of 
the National Academy of Sciences, EPA anticipates that the U.S. 
Department of the Interior (DOI) will take the lead in developing these 
regulations. EPA will work closely with DOI throughout that process.
4. Municipal Solid Waste Landfills
    The issue receiving the majority of comment in this section focused 
on the applicability of the rule to MSWLFs accepting CCR. The vast 
majority of commenters on this issue requested that EPA clarify that 
permitted MSWLFs, receiving CCR as daily cover or for disposal were not 
covered by the rule.
    While most CCR is currently disposed of at electric utility owned 
CCR landfills or surface impoundments, there is no prohibition against 
disposing of CCR in state-permitted MSWLFs. However, many commenters 
interpreted the proposed CCR subtitle D regulations to apply to a state 
permitted MSWLF disposing of CCR, which as a consequence would be 
subject to the additional burden of posting documentation to a Web 
site, having a professional engineer review certification, etc. (See 75 
FR 35210, where the preamble states that 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.) Commenters argued 
that since MSWLFs were never mentioned in the proposed rule, that it 
should be made clear that the rule did not apply to these facilities. 
Commenters further contended that since the requirements for CCR 
landfills were directly modeled from the MSWLF requirements found at 40 
CFR part 258, disposal in MSWLFs would be protective of human health 
and the environment. Commenters also contended that a benefit of MSWLFs 
would be their ability to provide additional capacity for the disposal 
of CCR as utilities seek to close, upgrade, or develop their own 
compliant CCR disposal sites.
    EPA recognizes that there are MSWLFs that either accept CCR for 
disposal, use CCR for as daily cover, or both. Since the proposed and 
final RCRA subtitle D standards for CCR landfills are modeled after the 
standards for MSWLFs found at 40 CFR part 258, EPA has concluded that 
disposal of CCR in MSWLFs is as protective as disposal in a CCR 
landfill and that permitted MSWLFs are not subject to the requirements 
of this rule. Like the MSWLF requirements, the CCR technical criteria 
require new units to have composite liners or their equivalent, and all 
units are subject to location restrictions, run-on and run-off 
controls, fugitive dust controls, groundwater monitoring and corrective 
action, closure and post-closure care requirements.\38\
---------------------------------------------------------------------------

    \38\ One significant difference however is that MSWLFs are 
required to have financial assurance, a requirement not applicable 
to CCR under the subtitle D requirements.
---------------------------------------------------------------------------

    While the MSWLF fugitive dust criteria (air criteria) are not as 
specific as those in this rule, Sec.  258.4(a) states that owners or 
operators of all MSWLFs must ensure that the units not violate any 
applicable requirements developed under a State Implementation Plan 
(SIP) approved or promulgated by the Administrator pursuant to section 
110 of the Clean Air Act, as amended. It is expected that states will 
impose additional requirements to address fugitive dusts, of the sort 
codified in Illinois' 415 ILCS 5/9(a)(2012) \39\ and enforced by the 
state (see People of the State of Illinois v. KCBX Terminals Company, 
Injunction no. 2013CH24788 in the Circuit Court of Cook County, 
Illinois. Moreover, if used as a daily cover, Sec.  258.21 requires 
that the alternative cover (i.e., CCR) control disease, vectors, odors, 
blowing litter, and scavenging without presenting a threat to human 
health and the environment.
---------------------------------------------------------------------------

    \39\ ``No person shall (a) Cause or threaten or allow the 
discharge or emission of any contaminant into the environment in any 
state so as to cause or tend to cause air pollution in Illinois, 
either alone or in combination with contaminants from other sources, 
or so as to violate regulations or standards adopted by the Board 
under this Act; (b) Construct, install or operate any equipment, 
facility, vehicle, vessel, or aircraft capable of causing or 
contributing to air pollution or designed to prevent air pollution, 
of any typed designated by Board regulations, (1) without a permit 
granted by the Agency unless otherwise exempt by this Act or Board 
regulations; or (2) in violation of any conditions imposed by such 
permit.''
---------------------------------------------------------------------------

    The Agency is not requiring MSWLFs that receive CCR for disposal or 
for use as daily cover to modify their groundwater monitoring programs 
to comply with the rule; however the Agency expects that State 
Directors will require MSWLFs to modify their MSWLF permits to address 
the addition of CCR to the unit as it relates to groundwater monitoring 
and corrective action. Section 258.54(a)(2) allows for the Director of 
an approved state to establish an alternative list of inorganic 
indicator parameters for a MSWLF unit if the alternative parameters 
provide a reliable indication of inorganic releases

[[Page 21342]]

from the MSWLF unit to the groundwater (i.e., as would be the case if 
CCR was disposed in the MSWLF unit). In determining alternative 
parameters, the Director shall consider, among other things: (1) The 
types, quantities, and concentrations in wastes managed at the MSWLF 
unit; (2) the mobility, stability, and persistence of waste 
constituents or their reaction products in the unsaturated zone beneath 
the MSWLF unit; and (3) the detectability of indicator parameters, 
waste constituents, and reaction products in the groundwater. In 
situations where the MSWLF unit is receiving CCR for disposal and/or 
daily cover, EPA expects the controlled management of CCR in these 
units. Specifically, EPA expects State Directors to utilize the 
provisions in Sec.  258.54(a)(2) to revise the detection monitoring 
constituents to include those constituents being promulgated in this 
rule under Sec.  257.90. These detection monitoring constituents or 
inorganic indicator parameters are: boron, calcium, chloride, fluoride, 
pH, sulfate and total dissolved solids (TDS). These inorganic indicator 
parameters are known to be leading indicators of releases of 
contaminants associated with CCR and the Agency strongly recommends 
that State Directors add these constituents to the list of indicator 
parameters to be monitored during detection monitoring of groundwater 
if and when a MSWLF decides to accept CCR.
    The Agency has concluded that CCR can readily be handled in 
permitted MSWLFs provided that they are evaluated for waste 
compatibility and placement as required under the part 258 
requirements. Furthermore, consistent with the recordkeeping 
requirements in Sec.  258.29, the Agency further expects State 
Directors to encourage MSWLF units receiving CCR after the effective 
date of this rule to do so pursuant to a ``CCR acceptance plan'' that 
is maintained in the facility operating record. This plan would assure 
that the MSWLF facility is aware of the physical and chemical 
characteristics of the waste received (i.e., CCR) and handles it with 
the additional precautions necessary to avoid dust, maintain structural 
integrity, and avoid compromising the gas and leachate collection 
systems of the landfill so that human health and the environment are 
protected. While the Agency sees no need to impose duplicative 
requirements for MSWLFs that receive CCR for disposal or daily cover; 
development of these acceptance plans as well as a revised list of 
groundwater detection monitoring constituents will help ensure that CCR 
is being managed in the most protective manner consistent with the Part 
258 requirements.
5. Inactive CCR Surface Impoundments
    The final rule also applies to ``inactive'' CCR surface 
impoundments at any active electric utilities or independent power 
producers, regardless of the fuel currently being used to produce 
electricity; i.e., surface impoundments at any active electric utility 
or independent power producer that have ceased receiving CCR or 
otherwise actively managing CCR. While it is true that EPA exempted 
inactive units from the part 258 requirements in 1990, the original 
subtitle D regulations at 40 CFR part 257 (which are currently 
applicable to CCR wastes) applied to ``all solid waste disposal 
facilities and practices'' except for eleven specifically enumerated 
exemptions (none of which are relevant). 40 CFR 257.1(c). See also, 40 
CFR 257.1(a)(1)-(2). And as discussed in greater detail below, subtitle 
D of RCRA does not limit EPA's authority to active units--that is, 
units that receive or otherwise manage wastes after the effective date 
of the regulations. EPA has documented several damage cases that have 
occurred due to inactive CCR surface impoundments, including the 
release of CCR and wastewater from an inactive CCR surface impoundment 
into the Dan River which occurred since publication of the CCR proposed 
rule. As discussed in the proposal, the risks associated with inactive 
CCR surface impoundments do not differ significantly from the risks 
associated with active CCR surface impoundments; much of the risk from 
these units is driven by the hydraulic head imposed by impounded units. 
These conditions remain present in both active and inactive units, 
which continue to impound liquid along with CCR. For all these reasons, 
the Agency has concluded that inactive CCR surface impoundments require 
regulatory oversight.
    The sole exception is for ``inactive'' CCR surface impoundments 
that have completed dewatering and capping operations (in accordance 
with the capping requirements finalized in this rule) within three 
years of the publication of this rule. EPA considers these units to be 
analogous to inactive CCR landfills, which are not subject to the final 
rule. As noted, EPA's risk assessment shows that the highest risks are 
associated with CCR surface impoundments due to the hydraulic head 
imposed by impounded water. Dewatered CCR surface impoundments will no 
longer be subjected to hydraulic head so the risk of releases, 
including the risk that the unit will leach into the groundwater, would 
be no greater than those from CCR landfills. Similarly, the 
requirements of this rule do not apply to inactive CCR landfills--which 
are CCR landfills that do not accept waste after the effective date of 
the regulations. The Agency is not aware of any damage cases associated 
with inactive CCR landfills, and as noted, the risks of release from 
such units are significantly lower than CCR surface impoundments or 
active CCR landfills. In the absence of this type of evidence, and 
consistent with the proposal, the Agency has decided not to cover these 
units in this final rule.
    Under both the subtitle C and subtitle D options, EPA proposed to 
regulate ``inactive'' CCR surface impoundments that had not completed 
closure prior to the effective date of the rule. EPA proposed that if 
any inactive CCR surface impoundment had not met the interim status 
closure requirements (i.e., dewatered and capped) by the effective date 
of the rule, the unit would be subject to all of the requirements 
applicable to CCR surface impoundments. Under the subtitle C option, 
those requirements would have included compliance with the interim 
status and permitting regulations. Under subtitle D, such units would 
have been required to comply with all of the criteria applicable to CCR 
surface impoundments that continued to receive wastes, including 
groundwater monitoring, corrective action, and closure.
    EPA acknowledged that this represented a departure from the 
Agency's long-standing implementation of the regulatory program under 
subtitle C. While the statutory definition of ``disposal'' has been 
broadly interpreted to include passive leaking, historically EPA has 
construed the definition of ``disposal'' more narrowly for the purposes 
of implementing the subtitle C regulatory requirements. For examples 
see 43 FR 58984 (Dec. 18, 1978); and 45 FR 33074 (May 1980). Although 
in some situations, post-placement management has been considered to be 
disposal triggering RCRA subtitle C regulatory requirements, e.g., 
dredging of impoundments or management of leachate, EPA has generally 
interpreted the statute to require a permit only if a facility treats, 
stores, or actively disposes of the waste after the effective date of 
its designation as a hazardous waste. EPA explained that relying on a 
broader interpretation was appropriate in this instance given that the

[[Page 21343]]

substantial risks associated with currently operating CCR surface 
impoundments, i.e., the potential for leachate and other releases to 
contaminate groundwater and the potential for catastrophic releases 
from structural failures, were not measurably different than the risks 
associated with ``inactive'' CCR surface impoundments that continued to 
impound liquid, even though the facility had ceased to place additional 
wastes in the unit. EPA noted as well that the risks are primarily 
driven by the older existing units, which are generally unlined.
    In the section of the preamble discussing the subtitle D option, 
EPA did not expressly highlight the application of the rule to inactive 
CCR surface impoundments, but generally explained that EPA's approach 
to developing the proposed subtitle D requirements for surface 
impoundments (which are not addressed by the part 258 regulations that 
served as the model for the proposed landfill requirements) was to seek 
to be consistent with the technical requirements developed under the 
subtitle C option. (See 75 FR 35193.) (``In addition, EPA considered 
that many of the technical requirements that EPA developed to 
specifically address the risks from the disposal of CCR as part of the 
subtitle C alternative would be equally justified under a RCRA subtitle 
D regime . . . The factual record--i.e., the risk analysis and the 
damage cases--supporting such requirements is the same, irrespective of 
the statutory authority under which the Agency is operating . . . Thus 
several of the provisions EPA is proposing under RCRA subtitle D either 
correspond to the provisions EPA is proposing to establish for RCRA 
subtitle C requirement. These provisions include the following 
regulatory provisions specific to CCR that EPA is proposing to 
establish: Scope and applicability (i.e., who will be subject to the 
rule criteria/requirements) . . .'') (emphasis added).
    EPA received numerous comments on this aspect of the proposal. On 
the whole, the comments were focused on EPA's legal authority under 
subtitle C to regulate inactive and closed units, as well as inactive 
and closed facilities. One group of commenters, however, specifically 
criticized the proposed subtitle D regulation on the grounds that it 
failed to address the risks from inactive CCR surface impoundments. The 
majority of commenters, however, argued that RCRA does not authorize 
EPA to regulate inactive or closed surface impoundments. These 
commenters focused on two primary arguments: first, that RCRA's 
definition of ``disposal'' cannot be interpreted to include ``passive 
migration'' based on the plain language of the statute, and second, 
that such an interpretation conflicted with court decisions in several 
circuits, holding that under CERCLA ``disposal'' does not include 
passive leaking or the migration of contaminants.
    In support of their first argument, commenters argued that the 
plain language of RCRA demonstrates that the requirements are 
``prospective in nature'' and thus cannot be interpreted to apply to 
past activities, i.e., the past disposals in inactive CCR units. They 
also argued that the absence of the word ``leaching'' from the 
definition of ``disposal'' clearly indicates that Congress did not 
intend to cover passive leaking or migration from CCR units. The 
commenters also selectively quoted portions of past EPA statements, 
claiming that these demonstrated that EPA had conclusively interpreted 
RCRA to preclude jurisdiction over inactive units and facilities. In 
particular, they pointed to EPA's decision in 1980 not to require 
permits for closed or inactive facilities.
    Commenters cited several cases to support their second claim. These 
include Carson Harbor Vill. v. Unocal Corp., 270 F.3d 863 (9th Cir. 
2001); United States v. 150 Acres of Land, 204 F.3d 698, 706 (2000); 
ABB Industrial Systems v. Prime Technology, 120 F.3d 351, 358 (2d Cir. 
1997); United States v. CMDG Realty Co., 96 F.3d 706, 711 (3rd Cir. 
1996); Joslyn Mfg. Co. v. Koppers Co., 40 F.3d 750, 762 (5th Cir. 
1994); Delaney v. Town of Carmel, 55 F. Supp. 2d 237, 256 (S.D.N.Y. 
1999); see also Interfaith Cmty. Org. v. Honey-Well Intl Inc., 263 F. 
Supp. 2d 796, 846 n.10 (D.N.J. 2003). The commenters acknowledged that 
these cases were all decided under CERCLA, but claim that the cases are 
all equally dispositive with respect to RCRA's definition of disposal 
because CERCLA specifically incorporates by reference RCRA`s statutory 
definition of disposal.
    As an initial matter, it is important to correct certain 
misunderstandings contained throughout a number of the comments. First, 
EPA did propose to include inactive units under the subtitle D 
alternative. EPA clearly signaled its intent to cover the same universe 
of units and facilities covered under the subtitle C proposal. EPA did 
not include a corresponding discussion in its explanation of the 
subtitle D alternative because application of the criteria to inactive 
units did not represent such a significant departure from EPA's past 
practice or interpretation. As discussed in more detail below, the 
original subtitle D regulations applied to all existing disposal units. 
See 40 CFR 257.1(a)(1)-(2), (c) and 43 FR 4942-4943, 4944.
    Second, several commenters criticized EPA's purported proposal to 
cover both ``closed'' and ``inactive'' surface impoundments, using the 
terms interchangeably. These same commenters also refer to both 
``inactive facilities'' and ``inactive units.'' These are all different 
concepts, and EPA clearly distinguished between them.
    EPA proposed to regulate only ``inactive'' surface impoundments 
that had not completed closure of the surface impoundment before the 
effective date. ``Inactive'' surface impoundments are those that 
contain both CCR and water, but no longer receive additional wastes. By 
contrast, a ``closed'' surface impoundment would no longer contain 
water, although it may continue to contain CCR (or other wastes), and 
would be capped or otherwise maintained. There is little difference 
between the potential risks of an active and inactive surface 
impoundment; both can leak into groundwater, and both are subject to 
structural failures that release the wastes into the environment, 
including catastrophic failures leading to massive releases that 
threaten both human health and the environment. This is clearly 
demonstrated by the recent spill in the Dan River in North Carolina, 
which occurred as the result of a structural failure at an inactive 
surface impoundment. Similarly, as demonstrated by the discovery of 
additional damage cases upon the recent installation of groundwater 
monitoring systems at existing CCR surface impoundments in Michigan and 
Illinois, many existing CCR surface impoundments are currently leaking, 
albeit currently undetected. These are the risks the disposal rule 
specifically seeks to address, and there is no logical basis for 
distinguishing between units that present the same risks.
    EPA did not propose to require ``closed'' surface impoundments to 
``reclose.'' Nor did EPA intend, as the same commenters claim, that 
``literally hundreds of previously closed . . . surface impoundments--
many of which were properly closed decades ago under state solid waste 
programs, have changed owners, and now have structures built on top of 
them--would be considered active CCR units.'' Accordingly, the final 
rule does not impose any requirements on any CCR surface impoundments 
that have in fact ``closed'' before the rule's effective date--i.e., 
those that no longer contain water and can no longer impound liquid.

[[Page 21344]]

    Further, EPA never proposed that the rule would apply to inactive 
facilities. The proposal was clear that the regulations would apply to 
active facilities--i.e., those that continue to generate electricity 
for distribution to the public, and those that continue to manage CCR. 
Consistent with that proposal, the final rule applies only to inactive 
surface impoundments at active electric utilities, i.e., facilities 
that are actively generating electricity irrespective of the fuel used.
    Finally, some comments focused on issues that were specific to the 
plain language of subtitle C provisions. While most of the issues the 
commenters raised relate equally to EPA's authority under both 
subtitles C and D, because the final rule establishes standards under 
subtitle D of RCRA, EPA has not addressed comments that are purely 
relevant or applicable to the extent of EPA's authority under subtitle 
C.
a. Plain Language of RCRA and EPA's Past Interpretations
    Under both subtitle C and subtitle D, EPA's authority to regulate 
``inactive'' units primarily stems from the agency's authority to 
regulate ``disposal.'' The term is defined once in RCRA and applies to 
both subtitles C and D. Moreover, the definition explicitly includes 
``leaking'' and ``placing of any solid waste . . . into or on any land 
so that such [waste] or any constituent thereof may enter the 
environment . . . or be discharged into any waters, including 
groundwaters.'' 42 U.S.C. 6903(3).
    Commenters focused on the past statements that EPA cited in the 
proposal in acknowledging that the Agency was proposing to revise its 
interpretation for this rulemaking. In general, the comments 
misconstrue the significance of these past statements. The cited 
passages merely explain that the permitting requirements in subtitle C 
were written to be ``prospective in nature'' and as a consequence, EPA 
has chosen to interpret ``disposal'' more narrowly in that context. 
Thus EPA's historic interpretation under subtitle C was not based on an 
interpretation that the plain language of RCRA's definition of 
``disposal'' precluded reaching inactive units, but on a determination 
that a narrower interpretation would be reasonable in light of specific 
language in sections 3004 and 3005, and the practical consequences of 
applying these requirements to inactive facilities.\40\
---------------------------------------------------------------------------

    \40\ It is also clear that certain subtitle C requirements in 
fact do apply to inactive units, for example, section 3004(u) 
requires facilities to clean up releases from inactive units located 
on the facility site.
---------------------------------------------------------------------------

    None of EPA's past statements included any interpretation that 
``leaking'' does not include leaking from an inactive disposal unit, or 
that the statutory definition of ``disposal'' cannot be interpreted to 
apply to the current consequences of past disposals. To the contrary, 
EPA was clear in the original 1978 proposed hazardous waste regulations 
that leaking from inactive disposal units constitutes ``disposal'' 
under RCRA.
    Neither RCRA nor its legislative history discusses whether section 
3004 standards for owners and operators of hazardous waste treatment, 
storage, or disposal facilities apply or were intended to apply to 
inactive facilities, i.e., those facilities which have ceased 
receiving, treating, storing, and disposing of wastes prior to the 
effective date of the subtitle C regulations. ``This is an important 
issue, however, because some, and perhaps most, inactive facilities may 
still be ``disposing of waste'' within the meaning of that term in 
Section 1004(3) of RCRA. `Disposal' includes: the discharge, dumping, 
spilling, leaking, . . . of any solid waste or hazardous waste into or 
on any land or water so that such solid waste or hazardous waste or any 
constituent thereof may enter the environment or be emitted into the 
air or discharged into any waters, including groundwaters. Many 
inactive facilities may well be leaking solid or hazardous waste into 
groundwater and thus be ``disposing'' under RCRA.'' 43 FR 58984 
(emphasis added).
    Note as well that EPA declined to impose requirements on ``inactive 
facilities'' not ``inactive units at active facilities,'' which are the 
entities covered in this final CCR rule. Further, the complications 
discussed in 1978 were specific to inactive or closed facilities: the 
concern that the present owner of the land on which an inactive site 
was located might have no connection (other than present ownership of 
the land) with the prior disposal activities. Id. These considerations 
are not relevant to inactive CCR surface impoundments at active 
electric utilities.
    EPA further clarified this position in the 1980 final hazardous 
waste rule, explaining that, while the Agency did not generally intend 
to regulate those portions of facilities that had closed before the 
effective date, there were exceptions to this, and that in individual 
cases, inactive portions of a facility--or in other words, inactive 
units, might be regulated.

    [O]wners and operators which continue to operate after the 
effective date of the regulations must ensure that portions of 
facilities closed before the effective date of these rules do not 
interfere with the monitoring or control of active portions. This 
requirement regulates the facility which operates under the RCRA 
regulations, although it may require the owner or operator before he 
receives a permit, or, as a permit condition, to take certain 
measures on portions of his facility closed before the effective 
date of these regulations.

45 FR 33068. (See also 45 FR 33170.)

    In other words, EPA was clear that its jurisdiction under RCRA 
extended to these portions of the facility but that the Agency had made 
a policy choice not to exert its regulatory jurisdiction as a general 
matter over inactive facilities, choosing instead to rely on section 
7003 and CERCLA to address the risks and require clean-up of these 
sites. EPA has adopted a substantially similar approach here, requiring 
the current owner or operator of an active facility to address the 
risks associated with an inactive portion of the facility that could 
potentially interfere with the monitoring or control of the actively 
operating portion of the facility through leaking contaminants or other 
releases.
    Similarly, in the 1980 final rules, EPA expressly declined to 
revise the regulatory definition of disposal to exclude accidental or 
unintentional releases. EPA noted that ``[r]egardless of whether a 
discharge of hazardous waste is intentional or not, the human health 
and environmental effects are the same. Thus intentional and 
unintentional discharges are included in the definition of `disposal.' 
'' (See 45 FR 33068.) While EPA revised other provisions to clarify 
that a permit would not be required for accidental discharges, EPA was 
clear that such activities are properly considered to be ``disposal.''
    By contrast, EPA's past implementation of subtitle D, following 
from the legislative history and the statutory language, consistently 
applied regulatory requirements equally to all facilities, without 
distinguishing between active and inactive or new and existing 
facilities.
    Congress was clear that subtitle D was intended to specifically 
address the problem of abandoned leaking ``open dumps'' scattered 
across the country, ``where frequently the use of the site for waste 
disposal is neither authorized nor supervised.'' H. Rep. No. 94-1491, p 
37, 94th Cong., 2d Sess (1976). For example, the report described the 
consequences when ``the City of Texarcana Arkansas/Texas, abandoned its 
six open dumps, in 1968'' to support the need to require open dumps to 
upgrade or close.

[[Page 21345]]

Similarly, in describing the need for the legislation, the House report 
stated:

    Disposal of solid wastes, including hazardous wastes, can have 
adverse environmental impacts in several ways. The following 
paragraphs discuss five different types of such impacts.
    (i) Perhaps the most pernicious effect is the contamination of 
groundwater by leachate from land disposal of waste. About half of 
the U.S. domestic water supply is from underground water, and thus 
is potentially subject to contamination. Such contamination is 
particularly vexing because often it is discovered after the damage 
is done and because the contamination is very long lasting. Thus 
leachate from a landfill or dump may not show up for years, maybe 
not even until after the landfill is closed.

Id. at 89 (emphasis added).

    Consequently, subtitle D of RCRA provides clear authority to 
address inactive or abandoned disposal sites. The relevant provisions 
of RCRA subtitle D do not distinguish between ``active'' and 
``inactive'' disposal units. Nor do any of the relevant provisions tie 
jurisdiction to the receipt or disposal of waste after a specific date.
    RCRA section 1004(14) defines an ``open dump'' as ``any facility or 
site where solid waste is disposed of which is not a sanitary landfill 
which meets the criteria promulgated under section [4004] of this 
chapter and which is not a facility for disposal of hazardous waste.'' 
42 U.S.C. 6903(14) (emphasis added). Section 4004(a) delegates broad 
authority to EPA to determine the facilities that will be considered 
``open dumps,'' without any requirement that the units or facilities be 
in operation. ``[T]he Administrator shall promulgate regulations 
containing criteria for determining which facilities shall be 
classified as sanitary landfills and which shall be classified open 
dumps within the meaning of this chapter.'' 42 U.S.C. 6944(a). Section 
4005(a), which is titled, ``Closing or upgrading of existing open 
dumps,'' is also not limited in scope: ``Upon promulgation of criteria 
under [1008(a)(3)] of this title, any solid waste management practice 
of disposal of solid waste or hazardous waste which constitutes the 
open dumping of solid or hazardous waste is prohibited, . . .'' 42 
U.S.C. 6945(a) (emphasis added). See also, section 4003(a)(3), 
requiring state plans to provide for the closing or upgrading of ``all 
existing open dumps''). 42 U.S.C. 6943(a)(3) (emphasis added).
    Consistent with the statutory provisions, EPA's current subtitle D 
regulations at 40 CFR part 257 apply to ``all solid waste disposal 
facilities and practices'' whether active or inactive, and did not 
differentiate between new and existing facilities.\41\ 40 CFR 257.1(c). 
See also, 40 CFR 257.1(a)(1)-(2). EPA was clear in both the proposed 
and final rules that the rules applied to all existing facilities: 
``These criteria for the classification of disposal facilities apply to 
all ``solid waste'' and ``disposal'' facilities, which are defined in 
the Act [in] (section 1004).'' 43 FR 4942-4943, 4944. The final rule 
was equally clear: ``These criteria apply to the full range of 
facilities and practices for ``disposal'' of ``solid waste,'' as those 
terms are defined in the Act.'' 44 FR 53440. (See also 44 FR 53438.) 
The final rule describes eight categories of materials or activities 
that are excluded; inactive facilities or units are not among them. 
This stands in stark contrast to the hazardous waste regulations, 
which, as discussed, specifically exempted inactive facilities from the 
permitting and associated regulatory requirements.
---------------------------------------------------------------------------

    \41\ The regulations establish eleven specifically enumerated 
exemptions, none of which are relevant to the units at issue.
---------------------------------------------------------------------------

b. Case Law on the Definition of Disposal
    EPA also disagrees with the commenters' second claim that 
regulating inactive surface impoundments would be inconsistent with 
case law in six circuits. The commenters are correct that some courts 
have held that the subsequent passive migration of contamination left 
on-site is insufficient to support liability against a third party that 
merely owned the property under CERCLA. But the commenters misconstrue 
this case law and fundamentally overstate its significance to the issue 
at hand. Of greater significance, however, is that federal courts have 
almost universally reached different conclusions under RCRA, holding 
that the statutory definition of disposal does include the passive 
migration of contamination from previously disposed of wastes.
    As an initial matter, the issue decided by the courts in the cited 
CERCLA cases was narrower than the commenters allege; these cases 
generally focused on whether current or past owners of land 
contaminated by the activities of other owners were liable for passive 
migration that occurred during their ownership of the land. This is 
very different than the situation at hand, in which regulatory 
requirements are being imposed to address the existing and future 
contamination caused by the past and current activities of the current 
owner.
    In addition, these decisions were largely predicated on language 
that is unique to CERCLA, rather than on a definitive reading of RCRA's 
definition of disposal. See, e.g., United States v. CMDG Realty Co., 
supra at 712-717. For example, in CMDG Realty, the court found that 
passive migration was not disposal because Congress had clearly 
distinguished between ``releases,'' and ``disposal,'' defining the two 
terms differently and imposing liability on different parties for the 
two activities. Id. Accord, Carson Harbor Village, supra, at 880-885; 
ABB Industrial Systems v. Prime Technology, supra at 358.
    Moreover, even under CERCLA courts have not universally reached the 
same conclusions on whether ``passive migration'' can be considered 
``disposal.'' See, e.g., Nurad, Inc. v. William E. Hooper & Sons Co., 
966 F.2d 837, 844-46 (4th Cir. 1992) (concluding that because the 
definition of disposal includes ``leaking,'' prior owners are liable if 
they acquired a site with leaking barrels or underground storage tanks 
even though the prior owner's actions are purely passive); ABB 
Industrial Systems, Id., n.3 (expressly declining to decide whether 
passive migration could ever be considered ``disposal'').
    But in any event, courts have consistently interpreted RCRA to 
apply to passive migration. Two cases under RCRA are the most directly 
analogous to the current situation as they address the extent of EPA's 
authority to regulate based on the statutory definition of 
``disposal'': In re Consolidated Land Disposal Regulation Litigation, 
938 F.2d 1386 (D.C. Cir. 1991), and United States v. Power Engineering 
Co., 10 F. Supp. 2d 1145 (D. Colo. 1998), aff'd 191 F.3d 1224 (10th 
Cir. 1999). In both cases, the court considered whether EPA could 
impose or enforce regulatory requirements to address passive migration 
under the interpretation that this constituted ``disposal'' under RCRA. 
And in both cases the court agreed that RCRA's definition encompassed 
such activities.
    The issue in Consolidated Land Disposal was whether EPA could 
require closed hazardous waste facilities to obtain a ``post-closure'' 
permit. 938 F.2d at 1388-1389. EPA had relied on the definition of 
disposal to support the regulation, concluding that a facility ``at 
which hazardous wastes have been disposed by placement in or on the 
land'' remains subject to both permitting and regulation because ``such 
hazardous wastes or constituents may continue `leaking' or `may enter 
the environment or be emitted . . . or discharged . . .' '' into the 
environment.'' Id. Similar to the commenters' current arguments, the 
petitioners argued that under Sec.  3005, a permit can only be required 
for ``on-

[[Page 21346]]

going activities''--the treatment, storage, or disposal of waste at 
such facilities--not for the facility itself post-closure. The 
petitioners argued that linguistically, ``disposal . . . is not a 
continuing activity but occurs anew each time waste is placed into or 
on land.'' The D.C. Circuit summarily rejected the petitioners' 
interpretation, holding that this ``may be one way in which the word is 
used in ordinary language, but is not necessarily how it is used in the 
statute; the equation of ``disposal'' with ``leaking,'' which is a 
continuous phenomenon rather than a discrete event, is enough to blunt 
the sting of the petitioners' point.'' Id. This case is essentially 
dispositive of the issue, given the similarities between the 
requirement for a post-closure permit and the final requirements 
applicable to inactive CCR surface impoundments. Electric utilities 
retain ownership and control over these existing CCR units, just as 
hazardous waste facilities retain ownership and control over the closed 
units subject to post-closure permitting. In both situations, EPA 
requirements are designed to address both the existing and future risks 
of further ``releases'' or ``leaking'' from these units--i.e., further 
disposal, as that term is defined in section 1004.
    Similarly, in Power Engineering the court considered whether under 
section 3008 of RCRA, EPA could bring an action to compel the operator 
of a metal refinishing plant to comply with the state's RCRA 
regulations relating to financial assurance.\42\ 10 F. Supp.2d at 1159. 
The defendants argued that since they were not currently disposing of 
waste, they were operating in compliance with state regulations and 
were exempt from financial assurance requirements. The court disagreed. 
It held that the use of the word ``leaking'' in the definition of 
``disposal'' indicated that the leaching of hazardous waste into the 
groundwater constitutes the continuing disposal of hazardous waste. Id. 
at 1159-60 (``Because the definition of ``disposal'' includes the word 
``leaking,'' disposal occurs not only when a solid waste or a hazardous 
waste is first deposited onto ground or into water, but also when such 
wastes migrate from their initial disposal location.'').
---------------------------------------------------------------------------

    \42\ Under RCRA's financial assurance regulations, owners and 
operators of hazardous waste facilities must document that they have 
sufficient resources to close their facilities and pay third-party 
claims that may arise.
---------------------------------------------------------------------------

    Courts in several circuits have also considered whether the passive 
migration of previously dumped waste constitutes a current or ongoing 
violation of RCRA, i.e., illegal ``disposal,'' under the citizen suit 
provisions of section 7002(a)(1)(A). Most have concluded that it does. 
See, Scarlett & Associates v. Briarcliff Center Partners, 2009 WL 
3151089 (N.D. Ga 2009) (deciding to ``follow the majority rule'' and 
holding that ``the continued presence of migrating waste constitutes a 
continuing violation under the RCRA''); Marrero Hernandez v. Esso 
Standard Oil Co., 597 F. Supp. 2d 272, 283 (D.P.R. 2009) (holding that 
unremedied, migrating contamination is not a wholly past violation); 
Cameron v. Peach County, GA, No. 5:02-CV-41-1 (CAR), 2004 WL 5520003 
(M.D. Ga. 2004) (holding that the continued presence of illegal 
contamination that remains remedial constitutes a continuing violation, 
even though the acts of unlawful disposal occurred in the past); 
California v. M&P Investments, 308 F. Supp. 2d 1137, 1146-1147 (E.D. CA 
2003) (Allowing RCRA 7002 claim of continuing violation to proceed on 
evidence that wastes ``continue to exist unremediated'' as a result of 
improper discharge that had ceased over 20 years prior to filing of 
suit); Aurora National Bank v. TriStar Marketing, 990 F. Supp. 1020, 
1025 (N.D. Ill. 1998) (``Although subsection (a)(1)(A) does not permit 
a citizen suit for wholly past violations of the statute, the continued 
presence of illegally dumped materials generally constitutes a 
`continuing violation' of the RCRA, which is cognizable under Sec.  
6972(a)(1)(A).'') (internal citation omitted); City of Toledo v. Beazer 
Materials & Servs., Inc., 833 F. Supp. 646, 656 (N.D. Ohio 1993) 
(``[T]he disposal of wastes can constitute a continuing violation so 
long as no proper disposal procedures are put into effect or as long as 
the waste has not been cleaned up and the environmental effects remain 
remediable.''); Gache v. Town of Harrison, 813 F. Supp. 1037, 1041-42 
(S.D.N.Y. 1993) (``The environmental harms do not stem from the act of 
dumping when waste materials slide off the dump truck but rather after 
they land and begin to seep into the ground, contaminating soil and 
water. So long as wastes remain in the landfill threatening to leach 
into the surrounding soil and water, a continuing violation sure may 
exist.''); Acme Printing Ink Co. v. Menard, Inc., 812 F. Supp. 1498, 
1512 (E.D. Wisc. 1992) (``RCRA includes in its broad definition of 
`disposal' the continuous leaking of hazardous substances. . . . 
Accordingly, leaking of hazardous substances may constitute a 
continuous or intermittent violation of RCRA.''); Fallowfield Dev. 
Corp. v. Strunk, No. 89-8644, 1990 WL 52745 (E.D. Pa. 1990) (``If a 
person disposes of hazardous waste on a parcel of property, the 
hazardous waste remains in that property insidiously infecting the soil 
and groundwater aquifers. In other words, the violation continues until 
the proper disposal procedures are put into effect or the hazardous 
waste is cleaned up.''). It is particularly notable that these cases 
were all decided under subsection (A); in contrast to subsection (B), 
section 7002(a)(1)(A) does not include any reference to liability for 
past actions or for prior owners. Compare, 42 U.S.C. 6972(a)(1)(A) and 
(B). In reaching their holdings, therefore, the courts necessarily 
relied [solely] on the reach of the statutory definition of 
``disposal,'' which is at the heart of EPA's authority to regulate 
inactive CCR surface impoundments.
    Courts have also addressed the limits of RCRA's definition of 
``disposal'' is in the context of an EPA action under RCRA section 
7003. Section 7003 authorizes EPA to obtain injunctive relief for 
actions, including disposal that ``may present an imminent and 
substantial endangerment to health or the environment.'' 42 U.S.C. 
6973(a). Several courts have evaluated whether an inactive disposal 
site, where no affirmative acts of disposal are occurring, constitute 
an ``imminent and substantial endangerment'' under this provision. Once 
again, most courts accept a definition of disposal that encompasses 
leaking or contaminant migration from previously discarded wastes. See 
United States v. Price, 523 F. Supp. 1055, 1071 (D.N.J. 1981), aff'd 
United States v. Price, 688 F.2d 204 (3rd Cir. 1982) (``There is no 
doubt, however, that [section 70003] authorizes the cleanup of a site, 
even a dormant one, if that action is necessary to abate a present 
threat to the public health or the environment.'') citing S. Rep. No. 
96-848, 96th Cong., 2d Sess., at 11 (1980); H. R. Rep. 96-1016 (Part 
I), 96th Cong., 2nd Sess., at 21 reprinted in [1980] U.S. Code Cong. & 
Ad. News, 6119, 6124; United States v. Waste Indus., 734 F.2d 159 (4th 
Cir. 1984) (Rejecting district court interpretation that disposal only 
includes ``active human conduct'' based on the inclusion of ``leaking'' 
in the definition of disposal, and interpreting the ``movement of the 
waste after it has been placed in a state of repose [to be] encompassed 
in the broad definition of disposal''); United States v. Diamond 
Shamrock Corp., 12 Envtl. L. Rep. 20819, 20821 (N.D. Ohio May 29, 1981) 
(noting that ``a disposal clearly requires no active human conduct''); 
United States v. Conservation Chemical Co.,

[[Page 21347]]

619 F. Supp. 162, 200 (D. Mo. 1985) (`` `disposal' occurs. . .when 
[wastes] migrate from their initial location''). See also S. Rep. 98-
284, p 58 (98th Cong. 1st Sess.) (``The Environmental Protection Agency 
and the Department of Justice have used the equitable authority and 
[sic] granted in section 7003 to seek court orders directing those 
persons whose past or present acts have contributed to or are 
contributing to the existence of an imminent and substantial 
endangerment to abate such conditions. This has been an intended use of 
the section 7003 since 1976. . . . An [sic] evidenced by the definition 
of `disposal' in section 1004(3), which includes the leaking of 
hazardous wastes, section 7003 has always provided the authority to 
require the abatement of present conditions of endangerment resulting 
from past disposal practices, whether intentional or unintentional.'').
    While EPA continues to maintain that the statutory definition of 
disposal does in fact authorize regulation of inactive CCR surface 
impoundments, this is not the sole basis for that authority. Under 
section 1008(a)(3), EPA is authorized to establish criteria governing 
solid waste management, which includes the ``storage'' of solid waste. 
42 U.S.C. 6904(28) and 6908(a)(3). RCRA's definition of ``storage'' is 
limited to hazardous waste; under subtitle D, therefore, the definition 
Congress intended was the dictionary definition, which incontrovertibly 
covers the activities associated with continuing to maintain CCR in 
inactive surface impoundments. For example, Merriam Webster defines 
``storage'' as ``the state of being kept in a place when not being 
used'' and ``the act of putting something that is not being used in a 
place where it is available, where it can be kept safely, etc.''
    Finally, consistent with the proposed rule and the final Regulatory 
Determination in Unit IV.B of this document, the final rule does not 
apply to CCR that is beneficially used.
6. Beneficial Use
    The proposed rule generally distinguished between the disposal of 
CCR and the beneficial use of CCR. Disposal activities would be subject 
to regulation under one of two alternative regulatory schemes. But 
under either alternative, beneficial use would remain Bevill exempt and 
would not be subject to regulation. The proposal identified specific 
criteria that would be used to distinguish between legitimate 
beneficial uses of CCR and the disposal of CCR. These criteria were 
largely drawn from the approach contained in the May 2000 Bevill 
Regulatory Determination. The criteria were:
    --The material used must provide a functional benefit. For example, 
CCR in concrete increases the durability of concrete--and is more 
effective in combating degradation from salt water; synthetic gypsum 
serves exactly the same function in wallboard as mined gypsum, and 
meets all commercial specifications; CCR as a soil amendment adjusts 
the pH of soil to promote plant growth.
    --The material substitutes for the use of a virgin material, 
conserving natural resources that would otherwise need to be obtained 
through practices, such as extraction. For example, the use of FGD 
gypsum in the manufacture of wallboard (drywall) decreases the need to 
mine natural gypsum, thereby conserving the natural resource and 
conserving energy that otherwise would be needed to mine natural 
gypsum; the use of fly ash in lieu of Portland cement reduces the need 
for cement. CCR used in road bed replace quarried aggregate or other 
industrial materials.
    --Where relevant product specifications or regulatory standards are 
available, the materials meet those specifications, and where such 
specifications or standards have not been established, they are not 
being used in excess quantities. For example, when CCR is used as a 
commercial product, the amount of CCR used is controlled by product 
specifications, or the demands of the user. Fly ash used as a 
stabilized base course in highway construction is part of many 
engineering considerations, such as the ASTM C 593 test for compaction, 
the ASTM D 560 freezing and thawing test, and a seven day compressive 
strength above 2760 kPa (400 psi). If excessive volumes of CCR are 
used--i.e., greater than were necessary for a specific project,--that 
could be grounds for a determination that the use is not beneficial, 
but rather is being disposed of. 75 FR 35162-35163.
    EPA explained that in the case of agricultural uses, CCR would be 
expected to meet appropriate standards, constituent levels, prescribed 
total loads, application rates, etc. EPA has developed specific 
standards governing agricultural application of biosolids. While the 
management scenarios differ between biosludge application and the use 
of CCR as soil amendments, EPA stated that the Agency would consider 
application of CCR for agriculture uses not to be a legitimate 
beneficial use if they occurred at constituent levels or loading rates 
greater than EPA's biosolids regulations allow. (75 FR 35162-35163, 
June 21, 2010)
    EPA proposed to codify these criteria in the term, ``beneficial use 
of coal combustion products (CCPs).'' This definition stated that the 
beneficial use of CCPs was the use of CCPs that provides a functional 
benefit; replaces the use of an alternative material, conserving 
natural resources that would otherwise need to be obtained through 
practices such as extraction; and meets relevant product specifications 
and regulatory standards (where these are available). CCPs that are 
used in excess quantities (e.g., the field-applications of FGD gypsum 
in amounts that exceed scientifically-supported quantities required for 
enhancing soil properties and/or crop yields), placed as fill in sand 
and gravel pits, or used in large scale fill projects, such as 
restructuring the landscape, are excluded from this definition. (75 FR 
35129-35130, June 21, 2010).
    Commenters generally supported the criteria in the proposal but 
raised concern that the criteria lacked specificity; some commenters 
stated that the criteria were those that states already considered in 
doing their beneficial use determination. Commenters also suggested the 
use of a ``no toxics'' provision and others suggested that the criteria 
include a requirement that ``environmental benefits'' be achieved. A 
more general comment raised by several commenters was that the proposed 
criteria failed to establish any standard that ensured protection of 
human health and the environment. Finally, one commenter raised concern 
that EPA's approach to beneficial use, and particularly to large scale 
fill operations, inappropriately assumed that these operations 
constituted the disposal of solid waste, which, the commenter claimed 
was inconsistent with a series of judicial decisions.
    There are generally three critical issues in determining whether a 
material is regulated under RCRA subtitle D: whether the material is a 
``solid waste,'' whether the activity constitutes ``disposal,'' and 
whether regulation of the disposal is warranted. Although there can be 
some overlap between these issues in that the same facts may be 
relevant to each of them, understanding the distinction between them is 
critical to understanding the final approach to the beneficial use of 
CCR adopted in this rulemaking.
    In order to be subject to RCRA, the material must be a solid waste. 
The statute defines a solid waste as ``any garbage, refuse . . . and 
other discarded material. . . .'' 42 U.S.C. 6903(27). As EPA noted in 
the proposed rule, for some beneficial uses, CCR is a raw

[[Page 21348]]

material used as an ingredient in a manufacturing process that have 
never been ``discarded,'' and thus, would not be considered solid 
wastes under the existing RCRA regulations. For example, synthetic 
gypsum is a product of the FGD process at coal-fired power plants. In 
this case, the utility designs and operates its air pollution control 
devices to produce an optimal product, including the oxidation of the 
FGD to produce synthetic gypsum. In this example, after its production, 
the utility treats FGD as a valuable input into a production process, 
i.e., as a product, rather than as something that is intended to be 
discarded. Wallboard plants are sited in close proximity to power 
plants for access to raw material, with a considerable investment 
involved. Thus, FGD gypsum used for wallboard manufacture is a product 
rather than a waste or discarded material. This use and similar uses of 
CCR that meet product specifications would not be regulated under the 
final rule.
    However, this does not describe the majority of CCR, which are 
unambiguously wastes; after generation in the boiler, they are placed 
into landfills or surface impoundments. While they may subsequently be 
dredged from these units and reused, placement in a landfill or surface 
impoundment presents prima facie evidence of discard. At the time the 
material is placed into the unit, the utility is not treating the 
material as a valuable product or otherwise seeking to protect the 
material for use. Although the material may subsequently be reused if a 
buyer is found, the material is originally placed in the unit with the 
intent to let it remain in place if no buyer is found. The waste 
designation does not change merely because a material in a surface 
impoundment or landfill may in the future be beneficially reused.
    For those materials that are ``wastes'' the second issue becomes 
relevant: whether the activities involved with the material constitutes 
``disposal'' or ``solid waste management.'' The statute distinguishes 
between these activities and ``use;'' several activities are listed in 
the definitions of ``disposal'' and ``solid waste management'' and 
``use'' is not among them. See 42 U.S.C. 6903(3) and (28). In general, 
commenters agreed that the three criteria in the proposal, and 
discussed above, would identify those activities that were properly 
considered to be legitimate beneficial uses rather than disposal. As 
several commenters noted, many state beneficial use programs rely on 
similar (or identical) criteria. And for encapsulated uses, EPA agrees 
that these three criteria are sufficient to distinguish between the 
activities that will be regulated as disposal under this final rule and 
those that will be considered beneficial use. Accordingly, EPA has 
adopted them in the final definition of ``beneficial use.''
    But as EPA acknowledged in the proposal, the issues are more 
difficult with regard to unencapsulated uses. Because these uses 
involve the direct placement of CCR on the land, they are clearly more 
analogous to activities that have consistently been considered to be 
``disposal.'' RCRA defines disposal to specifically include the 
``placing of any solid waste or hazardous waste into or on any land or 
water so that such solid waste or hazardous waste or any constituent 
thereof may enter the environment . . .'' 42 U.S.C. 6903(3). The issue 
is further complicated by the fact that there can be risks associated 
with placement of unencapsulated CCR on the land. As described in the 
proposal, CCR can leach toxic metals at levels of concern. The major 
risks associated with the placement of unencapsulated CCR on the land 
for beneficial use involved using large volumes of CCR to restructure 
the landscape, such as occurred at the Battlefield golf course, and 
placement in quarries and sand and gravel pits, such as occurred at the 
Gambrills, Maryland site. EPA acknowledged in the proposal that these 
types of operations would be subject to regulation as disposal, and so 
were not directly on point. However, because these damage cases 
involved the placement of unencapsulated CCR on the land, they raised 
questions regarding the safety of other uses of unencapsulated CCR that 
involved direct placement on the land. In addition, previous risk 
analyses do not address many of the use applications currently being 
implemented, and have not addressed the improved leachate 
characterization methods. EPA also noted that some scientific 
literature indicates that the uncontrolled (i.e., excessive) 
application of CCR can lead to the potentially toxic accumulation of 
metals.\43\
---------------------------------------------------------------------------

    \43\ See, for example, ``Effects of coal fly ash amended soils 
on trace element uptake in plant,'' S.S. Brake, R.R. Jensen, and 
J.M. Mattox, Environmental Geology, November 7, 2003 available at 
http://www.springerlink.com/content/3c5gaq2qrkr5unvp/fulltext.pdf; 
See information regarding the Town of Pines Groundwater Plume at 
http://www.epa.gov/region5superfund/npl/sas_sites/INN000508071.htm. 
Also see additional information for this site at http://www.epa.gov/region5/sites/pines/#updates.
---------------------------------------------------------------------------

    As noted, several commenters raised concern that EPA's beneficial 
use criteria did not include any standard that ensured protection of 
human health and the environment. EPA agrees that a criterion that 
accounted for the potential risks of the land placement of 
unencapsulated CCR would be an appropriate element to include in 
differentiating between disposal and beneficial use. RCRA's definition 
of disposal includes some elements related to risk: specifically, the 
definition includes as a relevant concept that the waste or any 
constituent of concern ``may enter the environment.'' In this regard it 
is also relevant that not all disposal activities are regulated by EPA 
under subtitle D; rather, EPA only regulates those that present risks 
that exceed the Agency's acceptable risk levels.
    Building off of these concepts, the Agency has developed an 
additional criterion to address both the question of whether the 
activity is appropriately considered to be ``disposal,'' and the 
question of whether that ``disposal'' warrants regulation. Because uses 
that fail to meet the beneficial use criteria will be considered 
disposal and would therefore be considered disposal subject to the 
final regulation, this fourth criterion was designed to exclude uses 
likely to present the same risks as the management practices regulated 
under other sections of the final rule. Thus, the final criterion 
directly correlates to the practices and the risks that the disposal 
regulations are designed to address: the risks associated with the 
placement of large quantities of CCR in a single concentrated location, 
such as a CCR landfill, as documented in the 2014 risk assessment and 
the damage cases.
    As discussed in more detail below, to be considered a ``beneficial 
use,'' prior to initiating an activity that involves placing 
unencapsulated CCR on the land in amounts greater than 12,400 tons, in 
non-roadway applications, the user must demonstrate that environmental 
releases to groundwater, surface water, soil and air are comparable to 
or lower than those from analogous products made without CCR, or that 
environmental releases to groundwater, surface water, soil and air will 
be at or below relevant regulatory and health-based benchmarks for 
human and ecological receptors during use.
    EPA acknowledges that there may be risks associated with uses that 
are below this threshold, depending on the characteristics of the CCR, 
the amount of material and the manner in which it is placed, and 
(perhaps most important) the site conditions. Consequently, all 
unencapsulated uses, including use in road construction and 
agriculture, should be conducted with care, according to appropriate 
management

[[Page 21349]]

practices, and with appropriate characterization of the material and 
the site where the material will be placed. However, as discussed in 
the previous section, because the amounts and, in some cases, the 
manner in which the CCR are used are very different from the land 
disposal modeled in the risk assessment, EPA cannot extrapolate from 
the risk assessment to reach conclusions regarding the risks these uses 
may pose. And in the absence of such information, EPA cannot establish 
criteria to regulate these uses.
a. Final Definition of the Term ``Beneficial Use of CCR''
    The final beneficial use criteria are as follows: (1) The CCR must 
provide a functional benefit; (2) The CCR must substitute for the use 
of a virgin material, conserving natural resources that would otherwise 
need to be obtained through practices such as extraction; (3) the use 
of CCR must meet relevant product specifications, regulatory standards, 
or design standards when available, and when such standards are not 
available, CCR are not used in excess quantities; and (4) when 
unencapsulated use of CCR involves placement on the land of 12,400 tons 
or more in non-roadway applications, the user must demonstrate and keep 
records, and provide such documentation upon request, that 
environmental releases to groundwater, surface water, soil and air are 
comparable to or lower than those from analogous products made without 
CCR, or that environmental releases to groundwater, surface water, soil 
and air will be at or below relevant regulatory and health-based 
benchmarks for human and ecological receptors during use. Any use that 
fails to comply with all of the relevant criteria will be considered to 
be disposal of CCR, subject to all of the requirements in the disposal 
regulations, and the user will be considered to be the owner or 
operator of a CCR disposal unit. Encapsulated uses need only comply 
with the first three criteria. Unencapsulated uses involving placement 
on the land of 12,400 tons or more in non-roadway applications that 
fail to meet all of the beneficial use criteria are considered a CCR 
unit. As previously noted, the first three criteria were discussed in 
the proposal and commenters generally supported these criteria, which 
establish flexible performance standards. As discussed above, the 
Agency has developed an additional criterion in response to comments, 
which generally reflects the issues discussed in the proposal. This 
additional criterion is designed to address the environmental and human 
health concerns associated with large-scale, unencapsulated uses that 
have features similar to landfills. These four criteria are discussed 
in greater detail in the sections below. Any user of CCR that, at a 
later time, believes that there could be a health or environmental 
issue associated with their beneficial use should work with their state 
agency to address any potential issue.
    As noted above, encapsulated uses of CCR must only comply with the 
first three criteria. Encapsulated beneficial uses are those that bind 
the CCR into a solid matrix that minimizes their mobilization into the 
surrounding environment. Examples of encapsulated uses include, but are 
not limited to: (1) Filler or lightweight aggregate in concrete; (2) a 
replacement for, or raw material used in production of, cementitious 
components in concrete or bricks; (3) filler in plastics, rubber, and 
similar products; and (4) raw material in wallboard production.
    Compliance with the first three criteria suffices because, as 
discussed in Unit IV of this document, the available information 
demonstrates that encapsulated uses of CCR raise minimal health or 
environmental concerns. The Agency did not receive any data to 
contradict this assessment during any of the comment periods. In 
addition, since publication of the proposal, the Agency conducted a 
study of FGD gypsum in wallboard and fly ash concrete, which further 
supports this conclusion. This study ``Coal Combustion Residual 
Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard'' 
(February 2014) concluded that ``environmental releases of constituents 
of potential concern (COPCs) from CCR fly ash concrete and FGD gypsum 
wallboard during use by the consumer are comparable to or lower than 
those from analogous non-CCR products, or are at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors.''
    Criteria 1: CCR must provide a functional benefit. This criterion 
is designed to ensure that the material performs a genuine function in 
the product or use; while it need not improve product performance when 
compared to the material for which it is substituting, CCR must 
genuinely be a necessary component of the product. In other words, 
there must be a legitimate reason for using CCR in the product other 
than the fact that it is an alternative to disposal of the material, 
e.g., the material fulfils material specifications. For example, CCR 
provides a functional benefit when used as a replacement for cement in 
concrete because the CCR increases the durability of the concrete and 
is also more effective against degradation from salt water. FGD gypsum 
serves the same function in the production of wallboard as mined 
gypsum, and meets all product specification. Additionally, CCR can be 
used to adjust the pH of soils thereby increasing and promoting plant 
growth.
    One commenter noted that many states already consider whether the 
material provides a functional benefit when making beneficial use 
determinations under their regulatory programs. The Agency agrees that 
this is an important criterion in determining whether a use is a 
``beneficial use.'' To the extent that a state regulatory program has 
determined that a particular use provides a functional benefit, this 
may serve as evidence that this criterion has been met.
    Criteria 2: CCR must substitute for the use of a virgin material, 
conserving natural resources that would otherwise need to be obtained 
through practices, such as extraction. This criterion is intended to 
ensure that the use is truly ``beneficial'' from an environmental 
perspective. Examples of CCR used as a substitute for a virgin material 
include FGD gypsum for mined gypsum and the use of fly ash in lieu of 
Portland cement thereby reducing the need for cement. The use of FGD 
gypsum in the manufacture of wallboard reduces the need to use virgin 
gypsum, thereby conserving natural resources (virgin gypsum) while 
conserving valuable energy that would be needed to mine the virgin 
gypsum. Similarly, the use of CCR fly ash in lieu of Portland cement 
reduces the overall need for cement. CCR used in a road bed application 
substitutes for the use of quarried natural materials that provide 
structural support for the road surface.
    One commenter again highlighted that many states consider this 
criterion in their current state beneficial use programs. The Agency 
agrees that this second criterion is appropriate, and that conserving 
natural resources is an important function that should be encouraged. 
Here as well, potential users of CCR materials may choose to rely on a 
state determination to provide evidence that this criterion has been 
met.
    Criteria 3: The use of CCR must meet relevant product 
specifications, regulatory standards, or design standards, when 
available, and where such specifications or standards have not been 
established, CCR may not be used in excess quantities. This criterion 
was intended to address both the legitimacy of the use and the 
potential environmental and human health

[[Page 21350]]

consequences associated with the use of excess quantities of CCR, 
particularly unencapsulated CCR. If excessive volumes of CCR are used--
i.e., greater than necessary for a specific project--that calls into 
question whether the purpose of the application was in fact a sham to 
avoid compliance with the disposal regulations. In addition, the record 
demonstrates that the risks from use of CCR are more likely to be 
associated with large volumes, particularly for unencapsulated uses.
    The Agency has modified this criterion slightly from the proposed 
rule. The proposed rule merely referenced ``relevant product 
specifications or regulatory standards'' and EPA was concerned that 
this was too narrow, and might not incorporate all of the relevant 
technical information currently available that provides guidance on 
what constitutes an excess amount. Consequently, in the final 
definition the Agency has added the phrase ``design standards.'' Design 
standards are different from product specifications, because they 
include things other than ``products.'' An example of a ``design 
standard'' would be technical guidance specifying that six inches of 
CCR is to be used in constructing a road.
    EPA received several comments on this provision, several of which 
criticized the sole reliance on engineering performance standards. For 
example, one commenter questioned how the Agency would quantify 
acceptable amounts for each use if no specifications or standards were 
in place. One commenter stated that the Agency needs to rely on more 
than the existence of engineering performance standards or comparisons 
to typical application rates of mined materials as coal combustion 
wastes are unique materials and comparisons to typical rates of 
application of natural gypsum or other soil amendments are 
inappropriate. Another commenter suggested a provision that would 
require users to follow a plan to only use what is necessary to reach 
the desired effect, in lieu of product specifications.
    EPA purposely did not attempt to establish product specifications 
for each potential beneficial use application. The potential products 
are too varied, and in many instances EPA lacks the necessary expertise 
(e.g., to develop manufacturing specifications for individual 
products.). Nor is such an approach necessary. When CCR substitutes for 
other materials, the amount used is typically controlled by product 
specifications, particularly for encapsulated uses. Product 
specifications currently exist for many, if not most, of the 
significant uses of CCR and can be found in a variety of sources. For 
example, as previously described, fly ash used as a stabilized base 
course in highway construction is subject to both regulatory standards 
under DOT/FHWA, and engineering specifications, such as the ASTM C 593 
test for compaction, the ASTM D 560 freezing and thawing test, and a 
seven-day compressive strength above 2760 kPa (400 psi).
    Similarly, in an agricultural setting, EPA expects all appropriate 
standards, constituent levels, prescribed total loads, and application 
rates to be met. For example, EPA has developed specific standards 
governing the agricultural application of biosolids. While the 
management scenarios differ between biosludge application and the use 
of CCR as soil amendments, EPA would consider application of CCR for 
agriculture uses not to be a legitimate beneficial use if they occurred 
at constituent levels or loading rates greater than EPA's biosolids 
regulations. Several commenters also noted that agronomic rates 
currently exist for certain items such as peanuts, cotton, tomatoes, 
corn and soybeans.\44\ EPA would generally consider application of CCR 
above these rates, or any other rate that has been scientifically 
justified, to constitute disposal rather than beneficial use.
---------------------------------------------------------------------------

    \44\ Commenters argued that, at least in agronomic settings, 
there is no incentive to use excess amounts because it simply 
increases the grower's cost.
---------------------------------------------------------------------------

    Many other sources of technical reports and documents exist for 
other uses. ASTM Standard E2277-03 provides standard guidance and a 
methodology for using CCR in a structural fill and includes a 
consideration of engineering properties and behaviors, testing 
procedures, and design considerations relevant to constructing a 
structural fill project using CCR. Industry guidance, such as USWAG's 
``Engineering and Environmental Guidance on the Beneficial Use of Coal 
Combustion Products in Engineered Structural Fill Projects'' may also 
provide information relevant to this issue. Further, some states, such 
as Wisconsin and Virginia, have developed environmental guidance for 
evaluating the suitability of a site prior to construction of a CCR 
structural fill.
    While many of these documents do not establish binding 
requirements, nor is EPA seeking to make them binding on users, they 
provide evidence of the design and construction practices, including 
the amounts that are typically used throughout the industry, and 
provide a basis on which to evaluate whether excessive quantities have 
been used in a particular application. These types of documents are 
also relevant in making judgments on the larger question--whether the 
activity is legitimate reuse or merely sham disposal. In essence, 
product specifications serve the same function as the requirement 
suggested by a commenter for a plan to only use what is necessary to 
reach the desired effect.
    Commenters were also concerned that the proposed standards, and 
particularly this criterion, did not include any provision that would 
ensure that CCR reuse was protective of human health and the 
environment. One commenter stated that product specifications and 
engineering standards do not speak to environmental risk or consumer 
exposure. This same commenter was concerned that the proposed criteria 
used circular logic by stating that excess materials were not to be 
used in cases where specifications or standards have not been 
established. Another commenter criticized this criterion because it did 
not include threshold levels that protect public health from the range 
of toxicants routinely found in coal ash.
    EPA generally disagrees that the requirement to ensure that 
excessive volumes have not been used is unrelated to environmental and 
safety concerns. Minimizing the amount of material used in a product or 
released to the environment decreases potential exposures to the 
material. EPA agrees, however, that an additional criterion that more 
directly addresses the potential health and environmental risks is 
appropriate for unencapsulated uses, which present the greater 
potential for exposures of concern. As discussed in more detail below, 
the Agency has added a criterion to specifically require users of 
unencapsulated CCR to demonstrate that environmental and health related 
standards have been met. The criterion is a general performance 
standard that is equally applicable to all sites and uses and will 
account for a wide variety of potential exposures. By contrast, in 
order to establish toxicant ``threshold levels,'' EPA would need to 
develop risk assessments that account for the wide variety of potential 
uses and exposures. This is neither practical nor feasible, given the 
site specific nature of the potential risks and the myriad of potential 
uses. In addition, EPA disagrees that this is necessary, as the 
performance standard laid out in the fourth criterion will 
appropriately address the risks documented in the current record for 
these uses.

[[Page 21351]]

Furthermore, as the Agency has previously stated in the May 2000 
Regulatory Determination and the 2010 proposal, leaving the Bevill 
determination in place for beneficial use does not conflict with EPA's 
view that certain beneficial uses, e.g., use in road construction and 
agriculture, should be conducted with care, according to appropriate 
management practices, and with appropriate characterization of the 
material and the site where the materials will be placed. EPA has 
concluded that the potential risks of these uses do not warrant federal 
regulation, but can be addressed, if necessary, in other ways.
    State programs exist and have the expertise to address beneficial 
use applications. In addition, the Agency is currently developing a 
framework to address the risks associated with the beneficial use of 
unencapsulated materials. This framework is expected to be finalized in 
2015; the framework will be available to assist in the implementation 
of issues associated with the unencapsulated uses of CCR. The Agency 
has also been working with the U.S. Department of Agriculture to 
address the risks associated with the agricultural use of CCR. In 
conclusion, the Agency believes that sufficient tools are available (or 
will soon be available) to address the site-specific risks associated 
with the beneficial use of CCR.
    Criteria 4: When unencapsulated use of CCR involving placement on 
the land of 12,400 tons or more in non-roadway applications, the user 
must demonstrate and keep records, and provide such documentation upon 
request, that environmental releases to groundwater, surface water, 
soil and air are comparable to or lower than those from analogous 
products made without CCR, or that environmental releases to 
groundwater, surface water, soil and air will be at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors during use. The Agency has established an environmental 
criterion to protect human health and the environment in response to 
numerous comments received on the proposal raising concern that 
additional provisions were necessary to ensure that unencapsulated uses 
of CCR needed to be conducted in an environmentally protective manner. 
The Agency discussed in the proposed rule the ways in which the use of 
CCR in an unencapsulated manner could affect groundwater, surface 
water, air and be associated with dust emissions. This fourth 
``environmental'' criterion requires potential users to addresses 
potential risks from all of these pathways in order to avoid compliance 
with the final disposal requirements. Existing sources of guidance and 
standards (e.g., ASTM E2277-03 and USWAG's ``Engineering and 
Environmental Guidance on the Beneficial Use of Coal Combustion 
Products in Engineered Structural Fill Projects,'' to name just two 
that are currently available), are available and may provide useful 
assistance for determining if the use of CCR are comparable to or lower 
than those from analogous products made without CCR, or that 
environmental releases to groundwater, surface water, soil and air will 
be at or below relevant regulatory and health-based benchmarks for 
human and ecological receptors during use. Information (e.g., modeling 
results, proposed designs, risk assessments, etc.) that have been 
proposed or developed to comply with state standards that explicitly 
address the environmental impacts of unencapsulated uses may also be 
relevant to this determination.
    i. Source of the 12,400 Ton Threshold and Fill Operations.
    As discussed earlier in this section, the fourth criterion was 
designed to address whether the activity is appropriately considered to 
be ``disposal'' and whether that ``disposal'' warrants regulation. 
Thus, the final criterion correlates to the practices and the risks at 
issue: The placement of large quantities of CCR in a single 
concentrated location, as documented by the 2014 risk assessment and 
the damage cases.
    In the proposed rule, EPA explained that the risks of greatest 
concern from unencapsulated beneficial uses were associated with the 
placement of CCR in quarries and sand and gravel pits, and with large 
scale fill operations used to re-grade the landscape. EPA generally 
proposed to define these operations as ``disposal'' rather than 
``beneficial use.'' As discussed below, EPA has retained that approach 
with respect to the placement in sand and gravel pits and quarries; 
consequently the fourth criterion need not account for these uses. By 
contrast, EPA has not definitively concluded that ``large scale fill 
operations,'' per se, constitute the disposal of CCR. This is because 
EPA agrees with commenters that, if constructed correctly, large scale 
fill operations can meet all of the criteria for a beneficial use. But 
EPA also agrees that these applications can present risks to human 
health and the environment, and therefore has drafted the fourth 
criterion to specifically address the risks presented by these 
operations. The fourth criterion is thus tied to the Agency's general 
approach to large scale fill.
    The Agency acknowledged in the proposal that additional guidance 
was warranted on what would constitute a large scale fill operation, 
and received numerous comments on this issue in response to the 
proposal. EPA requested comments again on the topic of large scale 
fills in a Notice of Data Availability (NODA). 78 FR 46940 (August 2, 
2013). The NODA discussed the fact that many commenters on the proposed 
CCR rule stated that EPA should have developed a size criterion to 
define large scale fill operations. One commenter suggested 5,000 cubic 
yards as a size criterion for a CCR landfill, but did not provide a 
basis for this. Other commenters suggested size criteria but for 
different reasons than defining disposal criteria; for example, 
Wisconsin has a standard where all CCR used for unconfined and confined 
``fill projects exceeding 5,000 cubic yards require concurrence by the 
State prior to commencement of the project.'' Similarly, West Virginia 
stated that ``unencapsulated use of CCR as structural fills not 
exceeding 10,000 cubic yards are approvable on a case-by-case basis.''
    In the NODA, EPA identified three different types of data sets that 
could provide information relevant to developing appropriate criteria 
or to otherwise defining what constitutes a ``large scale'' fill 
operation. EPA solicited comment on the adequacy of the data sets and 
whether EPA should consider them for the purpose of creating criteria 
or a definition. The three data sets were: (1) The size of the 
structural fills that have resulted in damage cases; (2) the 
distribution of landfill sizes, derived either from an EPA Office of 
Water's questionnaire or from the landfill size distribution used in 
the proposed rule; and (3) the size distribution for large scale fills 
that have been constructed in North Carolina. Many commenters argued 
that it was entirely inappropriate for EPA to specify in the rule when 
a project constitutes beneficial use simply by volume or amount of 
structural fill necessary to construct a stable base for a building. 
Commenters argued that a large scale fill operation, if designed 
appropriately, constituted a legitimate beneficial use. In fact, 
industry commenters universally claimed that they were not aware of any 
damage cases or adverse environmental impacts associated with 
structural fills that had adhered to industry guidance (e.g., ASTM 
standard E2277-03 for structural fills and the USWAG Engineering and 
Environmental Guidance on the Beneficial Use of CCPs

[[Page 21352]]

in Engineered Structural Fill Projects), and argued that the history of 
well-designed and implemented engineered structural fills demonstrate 
that CCR can serve as a valuable resource in avoiding disturbing native 
ground to secure borrow soils where fill materials are needed to 
establish a final grade for a project site that meets the need of the 
proposed final use. To this end, the commenters also acknowledged that 
site characterization and characterization of the CCR are fundamental 
to the construction of fills across the U.S. Similarly, other 
commenters stated that size should not be the only criterion used to 
define large scale fill operations and highlighted that the site 
conditions, including such features as the hydraulic conductivity of 
the area, should also be an important criterion to consider. Still 
other commenters stated that CCR landfills cannot include large scale 
fill CCR beneficial use projects because such operations do not involve 
disposal of a solid waste. Rather, industry commenters argue that the 
determination as to what is disposal as opposed to beneficial use 
should be a determination that rests solely with state agencies. These 
commenters suggested that the determination as to whether a particular 
fill project constituted disposal, rather than beneficial use should be 
based on a series of factors, and not simply a size-cut-off. Finally, 
other commenters argued that the Agency incorrectly presumed that only 
large scale fill operations could cause environmental damage, and 
suggested that rather than regulating large scale fill operations 
solely on the basis of the volume or the amount of CCR involved, the 
information available to EPA from damage cases and monitoring data 
suggests that an additional, if not primary criteria for regulating 
fill operations, including those involved in highway construction, 
should include the prevention of CCR coming into contact with water. 
Focusing on the risks of concern--that large scale fills were 
effectively operating as landfills--the Agency reviewed the database of 
landfills used in the 2014 risk assessment and has established a 
threshold limit that corresponds to the smallest size landfill in the 
risk assessment database. EPA selected this threshold as the trigger 
for requiring an affirmative demonstration by the user that there will 
be no releases of concern as a consequence of the land application, 
because the available evidence in the record (i.e., the 2014 risk 
assessment) demonstrates that at these volumes the potential risks are 
of such significance to warrant regulation. Based on this evidence, the 
burden then shifts to the potential user to demonstrate that these 
potential risks do not exist at the particular site or have been 
adequately mitigated. Under this approach, unencapsulated beneficial 
use applications greater than or equal to 12,400 tons can still be 
conducted without becoming subject to the disposal regulations by using 
engineering principles, such as a liner system, and demonstrating that 
environmental releases to groundwater, surface water, soil and air are 
comparable to or lower than those from analogous products made without 
CCR, or that environmental releases to groundwater, surface water, soil 
and air will be at or below relevant regulatory and health-based 
benchmarks for human and ecological receptors. EPA agrees that the 
volume of CCR involved should not be the sole basis for determining 
whether an operation constitutes disposal. As such, the Agency is 
requiring the use of the fourth criterion in order to address any 
potential risks associated with unencapsulated uses of CCR that are in 
excess of 12,400 tons. Users will be required to make an affirmative 
demonstration relating to the potential environmental releases and the 
potential risks of the application (in addition to requiring compliance 
with the other three criteria). Specifically, users will be required to 
demonstrate that environmental releases to groundwater, surface water, 
soil and air are comparable to or lower than those from analogous 
products made without CCR, or that environmental releases to 
groundwater, surface water, soil and air will be at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors during use. EPA expects such determinations to take into 
account a wide variety of factors, including the hydraulic conductivity 
of the area, proximity of the material to water, and the likelihood of 
contact with water. EPA also expects that such determinations would 
take into account, as many commenters acknowledged to be appropriate 
and necessary, the need for site characterization and characterization 
of the CCR. The fourth criterion was adopted in part, to address 
commenters' concern that the EPA should include a criterion that 
prevents the placement of CCR in water sources. These are legitimate 
concerns; existing damage cases show that the placement of CCR in sand 
and gravel pits was almost always associated with CCR being placed in 
contact with water. The fourth criterion will require the user to 
demonstrate that environmental releases to groundwater, surface water, 
soil and air are comparable to or lower than those from analogous 
products made without CCR, or that environmental releases to 
groundwater, surface water, soil and air will be at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors during use. As a consequence of this requirement, EPA expects 
that significant changes may need to be made in order to proceed with a 
proposed use; for example, conducting the required assessment, may 
demonstrate that the only way to achieve the performance standard is to 
install engineering features, such a liner, as part of the proposed 
project.
    Application of unencapsulated CCR to the land in volumes less than 
the 12,400 tons will not require an affirmative demonstration to be 
considered a beneficial use. While the Agency has sufficient 
information to document that unencapsulated uses can present a hazard, 
based on the current rulemaking record, EPA lacks the information 
necessary to demonstrate that unencapsulated uses in smaller amounts 
are likely to present a risk.\45\ In other words, the evidence relating 
to these uses is not sufficient to shift the burden to the potential 
user to affirmatively demonstrate the safety of the proposed use. 
Nevertheless, the Agency expects potential users of unencapsulated CCR 
below this threshold to work with the states to determine the potential 
risks of the proposed use at the site and to adopt the appropriate 
controls necessary to address the risks. In this regard, EPA notes that 
the composition and leaching behavior of CCR being beneficially used 
may change over time due to upgrades in air pollution controls devices 
at coal-fired power plants. Further, initial determinations for 
existing beneficial use (BU) applications may have relied on single-
point pH test methods (e.g., TCLP, SPLP) that, depending on actual 
field conditions in which the applications are occurring, can under- or 
over-estimate leachate concentrations. Scientific advancements

[[Page 21353]]

in leach test protocols have found that the degree of leaching can vary 
by several orders of magnitude. Accordingly, states overseeing CCR BU 
programs are encouraged to closely evaluate existing BU applications in 
light of ongoing scientific advances in tools and technologies to 
ensure these applications remain protective of human health and the 
environment. In addition, the Agency is working to provide assistance 
to states and potential users; this includes the release of the 
Agency's Industrial Waste Evaluation Model (IWEM), and the development 
of a framework for systematically assessing unencapsulated BU 
applications to aid in assessing whether there are environmental risks 
associated with site specific structural fills.
---------------------------------------------------------------------------

    \45\ In November 2014, EPA received reports alleging that 
extensive groundwater monitoring data collected by the Wisconsin 
Department of Natural Resources demonstrated a correlation between 
beneficial uses of unencapsulated CCR below these thresholds and 
contaminated drinking water wells in southeastern Wisconsin. 
Insufficient time was available to allow EPA to evaluate these 
reports as part of this rulemaking. However, EPA will continue to 
evaluate the issues associated with unencapsulated uses of CCR, and 
to the extent available data demonstrate the need for revisions to 
these criteria, EPA will initiate the necessary rulemaking 
procedures.
---------------------------------------------------------------------------

    ii. Exclusion of Roadway Applications from the 4th Criterion. In 
the 2010 proposal, the Agency stated that the placement of 
unencapsulated CCR on the land, such as in road embankments, presented 
concerns, but that the amount and the manner in which they are used--
subject to engineering specifications and material requirements rather 
than landfilling techniques--are very different from land disposal. The 
Agency highlighted the 2005 guidance that was developed by EPA, FHWA, 
DOE, ACAA, and USWAG, addressing the appropriate methodologies and 
engineering requirements for the use of coal ash in highway 
construction. Lastly, the Agency noted the difference in terms of 
volume; the difference between the amounts of CCR that could be 
disposed of in a landfill vs. the amount of CCR used in the 
construction of a roadbase (typically on the order of six to twelve 
inches thick).
    EPA received a number of comments requesting that the definition of 
a CCR landfill exclude CCR used in highway and road construction 
projects and similar beneficial use projects authorized by an 
appropriate state agency. These commenters reasoned that the 
``arbitrary cutoff' discussed in the NODA would inappropriately capture 
such uses.
    The Agency has excluded roadways and associated embankments from 
the fourth criterion because the methods of application are 
sufficiently different from CCR landfills that EPA cannot extrapolate 
from the available risk information to determine whether these 
activities present similar risks. Roadways are subject to engineering 
specifications that generally specify CCR to be placed in a thin layer 
(e.g., six to 12 inches) under a road. The placement under the surface 
of the road limits the degree to which rainwater can influence the 
leaching of the CCR.
    There are also significant differences between the manner in which 
roadways and landfills can potentially impact groundwater. These 
include the nature of mixing in the media, the leaching patterns, and 
how input infiltration rates are generated. First, CCR landfills are 
typically a homogenously mixed system, and as a result, there are no 
spatial variations of the chemical and physical properties of the media 
(for example, bulk density, hydraulic conductivity and contaminant 
concentration). By contrast, roadways are generally constructed of 
several layers with different material properties (heterogeneity). This 
difference affects the hydraulic conductivity of a mass of CCR in a 
landfill, as compared to CCR placed in an embankment. Any potential 
leaching will tend to spread over the length of the embankment, as 
opposed to the leaching in a downward motion that would occur in a 
homogenously filled landfill.
    Finally, (and perhaps most critically) the construction of roads 
and associated embankments are supervised and approved by State and/or 
Federal Department of Transportation (DOT) engineers who ensure 
compliance with engineering specifications
    While EPA is exempting roadbed applications of 12,400 tons or 
larger from the fourth criterion, EPA is mindful of situations where 
large quantities of CCR have been used without appropriate engineering 
controls or where placement on the land has apparently far exceeded 
those necessary for the engineering use of the materials. One such 
situation occurred in Puerto Rico with CCR generated by the AES Coal 
Fired Power Plant in Guayama. As discussed in Unit IV.B of this 
document, CCR and an aggregate created from them (``AGREMAX'') were 
being used as fill in housing developments and in road projects. Over 
two million tons of this material was used between 2004 and 2012. When 
made aware of the situation, EPA raised concerns over the use of CCR 
and AGREMAX based on the fact that the Environmental Quality Board had 
not imposed engineering controls, specified appropriate uses, or 
otherwise limited the use of AGREMAX by the end users. Inspections of 
some of the sites where the material had been placed showed use in 
residential areas, areas close to wetlands and surface waters and/or 
over shallow sole source drinking water aquifers. In addition, in some 
cases the volumes appeared to be in excess of what was necessary for 
engineering uses and some sites appeared to be abandoned. This kind of 
situation will be directly addressed by the new beneficial use criteria 
promulgated in the final rule. To qualify as a beneficial use, the use 
of AGREMAX would need to meet all four of the criteria--that is, it 
must provide a functional benefit, substitute for a virgin material, 
meet product specifications, and in this case, the user would be 
required to make the environmental demonstration for the non-roadbed 
applications.
    iii. Kinds of unencapsulated uses of CCR required to comply with 
the fourth criterion.
    Unencapsulated uses of CCR are numerous and range, in total use, 
from hundreds of thousands of tons to millions of tons per year. These 
applications include, as examples, the following: (1) Flowable fill; 
(2) structural fills; (3) soil modification/stabilization; (4) waste 
stabilization/solidification; (5) use in agriculture as a soil 
amendment; and (6) aggregate.
    Many of these unencapsulated uses, other than structural fills, are 
not generally expected to be used in amounts that would require an 
environmental demonstration under the fourth criterion. And for several 
of these applications, which can be structurally very different from 
landfills, EPA expects that even if these applications are used in 
amounts greater than 12,400 tons, potential users will be easily able 
to meet the performance standard. For example, the use of CCR for soil 
modification or stabilization, agriculture, waste stabilization/
solidification, aggregate or flowable fill applications, is generally 
not similar to the mounding that occurs in a landfill situation. These 
differences can have a tremendous bearing on the leaching potential of 
the CCR materials.
    Structural fills, however, can be larger applications and so may be 
required to demonstrate compliance with the environmental standards in 
the fourth criterion more frequently. In addition, because structural 
fills can be similar to the landfills regulated in the final disposal 
rule, some proposed applications may need to install engineering 
features to meet the performance standard.
    iv. Demonstration that ``environmental releases to groundwater, 
surface water, soil and air are comparable to or lower than those from 
analogous products made without CCR, or that environmental releases to 
groundwater, surface water, soil and air will be at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors during use.''

[[Page 21354]]

    The environmental fourth criterion requires a potential use of CCR 
to compare analogous products or to perform an environmental assessment 
evaluating whether releases to the environment are at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors during use. A demonstration should consider the development 
of a conceptual model to assist in the determination of whether the 
environmental criteria contained in the definition of the term 
``beneficial use of CCR'' can be demonstrated. Numerous potential 
pathways exist and these should be evaluated as necessary depending on 
the potential application of the CCR. Potential exposure pathways 
include exposure to groundwater, surface water, air, and soils. 
Generation of dust, leaching to groundwater and surface water, 
inhalation of mercury, and plant uptake are areas that need to be 
evaluated. A complete evaluation of the types of releases, the types of 
exposure and the receptors that may be potentially affected by a 
potential application will need to be conducted. A screening comparison 
will need to be performed comparing the concentrations of individual 
constituents of potential concern to the following benchmarks: human 
soil ingestion, ecological soil, tap water ingestion, fish ingestion, 
surface water, sediment, and inhalation. As an example, a user could 
compare a mercury concentration to a human health screening benchmark 
with an inhalation value of 300 ng/m\3\. Existing documents that can be 
used to gain an understanding of conceptual models, pathways and 
regulatory limits include: Risk Assessment Guidance for Superfund, 
Exposure Factors Handbook, Volumes I, II and III, Risk Assessment 
Guidance for Superfund Volume I: Human Health Evaluation Manual Part A, 
Industrial Waste Management Model (IWEM) Technical Backgrounds 
Document, Exposure Factors Handbook, Human and Ecological Risk 
Assessment of Coal Combustion Wastes. In addition, although it is not 
directly applicable, a potential user of unencapsulated CCR may find it 
useful to consult the previously mentioned ``Coal Combustion Residual 
Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard'' 
and the ``Methodology for Evaluating Encapsulated Beneficial Uses of 
Coal Combustion Residuals'' to assist in the determination of whether 
the unencapsulated CCR is comparable to or lower than those from 
analogous products made without CCR, or that environmental releases to 
groundwater, surface water, soil and air will be at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors during use.
    After the effective date of the final rule, any potential user of 
CCR that makes the demonstration in the fourth criterion must keep 
records and provide such documentation upon request.
b. Placement in Sand and Gravel Pits and Quarries
    EPA proposed that, without exception, unencapsulated CCR placed in 
sand and gravel pits, and quarries should not constitute beneficial 
use, but disposal. The Agency highlighted a number of damage cases that 
involved the filling of old, unlined quarries or gravel pits with large 
quantities of unencapsulated CCR, under the guise of ``beneficial 
use.'' Because of the damage cases and the concern that in such 
instances, sand and gravel pits and quarries were essentially operating 
as landfills, EPA proposed to define the placement of CCR in sand and 
gravel pits or quarries as land disposal that would be subject to 
regulation under either of the proposed regulatory options. The 
proposal specifically defined a CCR landfill as a disposal facility or 
part of a facility where CCR are placed in or on land and which is not 
a land treatment facility, a surface impoundment, an underground 
injection well, a salt dome formation, a salt bed formation, an 
underground mine, a cave, or a corrective action management unit. For 
purposes of this part, landfills also include piles, sand and gravel 
pits, quarries, and/or large scale fill operations. Sites that are 
excavated so that more coal ash can be used as fill are also considered 
CCR landfills.
    Commenters stated that there were numerous examples of harm caused 
by the unencapsulated ``reuse'' in sand and gravel pits and quarries, 
which demonstrate that these unencapsulated uses were merely disposal 
in disguise, and must be regulated stringently under Subtitle C of RCRA 
to prevent the risks they pose of contaminating groundwater, surface 
water, and ecological systems with heavy metals and other harmful 
pollutants. In particular, they argue that ``There have already been at 
least 13 damage cases caused by the disposal of coal ash in sand and 
gravel pits or former quarries that led to contamination of water 
sources and/or ecological damages.'' Some commenters also agreed that 
placement in sand and gravel pits and quarries should not be considered 
beneficial use. For example, one commenter agreed that CCR placement in 
sand and gravel pits and quarries is ``disposal'' and not beneficial 
use while another commenter wrote that it concurs that large-scale 
fills in quarries in poorly engineered applications can cause negative 
impacts. Other commenters highlighted that damage cases related to sand 
and gravel pits and quarries were old practices that no longer take 
place. These commenters argued that while sand and gravel quarries have 
been used to dispose of CCR, it is not correct to assume that with 
proper engineering and environmental standards that CCR cannot be used 
beneficially to reclaim quarries for uses such as recreational areas, 
commercial or industrial uses, or to aesthetically improve the 
characteristics of the land.
    EPA is finalizing its proposal that placement of CCR in sand and 
gravel pits constitutes disposal, rather than beneficial use. The final 
definition of a CCR landfill explicitly includes placement of CCR in 
sand and gravel pits and quarries. EPA has adopted this approach 
because the practice has resulted in numerous damage cases as a result 
of the highly permeable strata typically present at such sites. 
Moreover, while the commenters may be correct that ``with proper 
engineering measures, placement in sand and gravel pits and quarries 
can be conducted safely'', they submitted no data to support this 
contention. The only engineering features the available information 
demonstrate would be protective are those that have been determined to 
be necessary for CCR landfills--i.e., composite liners and groundwater 
monitoring. And in the absence of these features, any future placement 
in sand and gravel pits and quarries could not meet the performance 
standard in the fourth criterion: i.e., that environmental releases to 
groundwater, surface water, soil and air will be at or below relevant 
regulatory and health-based benchmarks for human and ecological 
receptors during use.

B. Definitions

    EPA proposed definitions for a number of key terms used in the 
proposed subtitle D rule that the Agency determined were necessary for 
the proper interpretation of the proposed requirements, e.g., coal 
combustion residuals, existing CCR landfill. (See 75 FR 35196-97, June 
21, 2010.) In addition, EPA also proposed definitions for terms that 
were specific to certain regulatory requirements, e.g., seismic impact 
zone.

[[Page 21355]]

    EPA is finalizing many of the regulatory definitions that were 
proposed, some with modifications. Several definitions that were 
proposed have been removed because they are no longer relevant to this 
rulemaking and a number of new definitions have been added. 
Specifically, definitions that have been removed from the final rule 
include: natural water table, probable maximum precipitation, surface 
water, systemic toxicants and upstream toe. New definitions are 
discussed in the technical section of the rule for which they apply. 
The majority of the regulatory definitions contained in the proposed 
rule have been retained in the final rule, as proposed or with minor 
clarifying changes. These definitions are codified in Sec.  257.53 and 
include the following: acre foot, active life, aquifer, area capacity 
curves, areas susceptible to mass movement, coal combustion residuals 
(CCR), displacement, facility, factor of safety, fault, freeboard, 
groundwater, hazard potential classification, high hazard potential 
surface impoundment, significant hazard potential surface impoundment, 
low hazard potential surface impoundment, holocene, hydraulic 
conductivity, karst terrain, lithified earth material, maximum 
horizontal acceleration in lithified earth material, new CCR landfill, 
new CCR surface impoundment, operator, owner, poor foundation 
conditions, recognized and generally accepted good engineering 
practices, representative sample, run-off, run-on, sand and gravel pit 
or quarry, seismic impact zone, state, structural components, unstable 
area, uppermost aquifer, and waste boundary.
    Several definitions received a significant number of comments and 
upon further evaluation by EPA have been modified to better explain 
their meaning or intent. This includes the definitions for the 
following terms: CCR landfill or landfill, CCR surface impoundment or 
impoundment, existing CCR landfill and existing CCR surface 
impoundment. These comments, along with the revisions made in response 
are discussed in more detail below. In addition, EPA has revised a 
number of definitions, or added new definitions, to be consistent with 
revisions made in the corresponding technical requirements. These are 
discussed in the various sections of the preamble that address the 
specific technical requirement. For example, as discussed in Unit V of 
this document, EPA has revised the definition of ``independent 
registered professional engineer or hydrologist'' to ``qualified 
professional engineer'' to address the concerns raised in comments.
1. Definition of CCR Landfill
    EPA proposed to define a CCR landfill as a disposal facility or 
part of a facility where CCR is placed in or on land and which is not a 
land treatment facility, a surface impoundment, an underground 
injection well, a salt dome formation, a salt bed formation, an 
underground mine, a cave, or a corrective action management unit. For 
purposes of this subpart, landfills also include piles, sand and gravel 
pits, quarries, and/or large scale fill operations. Sites that are 
excavated so that more coal ash can be used as fill are also considered 
CCR landfills. (See 75 FR 35239.) The Agency received a significant 
number of comments on the proposed definition. These comments focused 
almost exclusively on the inclusion of ``large-scale fill operations'' 
and ``piles'' within the definition of CCR landfill. Regarding large-
scale fills, commenters argued that one of the fundamental problems 
with the proposed definition was that it assumed all CCR placed in 
large scale fill operations constituted ``disposal'' of CCR (and that 
these operations therefore constitute CCR landfills) rather than 
beneficial use. Commenters further argued that CCR is often used in 
engineered fills, such as road base and road embankments and that these 
legitimate beneficial use operations should not be subject to the CCR 
landfill regulations.
    Commenters also argued that ``piles'' should be omitted from the 
definition of a CCR landfill for a variety of reasons. Several 
commenters argued that including the word ``pile'' was overly broad and 
insufficiently prescriptive and would inappropriately capture on-going 
or short-term CCR management activities that did not constitute 
disposal, such as storage for beneficial use. These commenters also 
raised concern that including ``piles'' in the definition of CCR 
landfill without further clarification or specificity, i.e., when used 
as part of a beneficial use operation, would negatively affect 
beneficial use activities. Other commenters raised concern that the 
term ``piles'' was too vague, and suggested that whether piles were 
treated as CCR landfills should be determined by the size of the piles, 
or the intent for which such piles exist. These commenters suggested 
the Agency should exclude small piles of CCR that are staged and/or 
consolidated prior to transport or placement for disposal. These 
commenters argued that subjecting all CCR piles to all of the landfill 
requirements was ``illogical and inappropriate.''
    Certain commenters argued that piles should not be regulated under 
this rule because they do not present a significant risk to the 
environment, as evidenced by a lack of damage cases. Alternately, other 
commenters suggested that if EPA were to regulate piles, the Agency 
should consider a regulatory strategy other than regulation as a CCR 
landfill. One alternative regulatory strategy suggested was to include 
an option establishing a limit (e.g., 180 days) on the amount of time 
that the CCR could be allowed to be maintained in a pile without 
regulation as a CCR landfill. Another option suggested was to develop a 
set of reasonable design and operating standards consistent with the 
uses and risks posed by piles. Such design standards could include the 
requirement for a low permeability underlayment or base such as 
asphalt, concrete or a high density polyethylene (HDPE) liner. 
Operating standards could include such provisions as labeling, and the 
requirement to remove at least 90 percent of the contents every 90 
days, with a full cleanout annually.
    EPA believes the suggested option to establish a time limit would 
be difficult to oversee and verify. States and citizens would have no 
way to determine when CCR is placed in a pile and when the CCR was 
subsequently removed. Therefore, EPA is rejecting this suggested 
option. The suggested option to develop appropriate design and 
operating standards is essentially the approach EPA has adopted, as 
discussed in more detail below. However, the final design and operating 
standards differ according to the management practices, and include 
measures to control fugitive dust, and for certain practices, require 
the installation of a composite liner and leachate collection system.
    EPA discussed its final approach to large-scale fill operations in 
Unit V of this document; the definition of a CCR landfill has been 
revised to be consistent with the approach described in that section. 
As explained at length, EPA has adopted a final approach that 
distinguishes between beneficial use and the ``disposal'' of CCR. 
Activities that meet the definition of beneficial use are not subject 
to these regulations. Activities that do not meet all of the criteria 
in the definition of a beneficial use--and in particular, such 
activities that involve the placement of unencapsulated CCR on the 
land--are considered disposal and are subject to the requirements of 
this final rule. Consistent with this approach the final definition of 
a CCR landfill has been revised to clarify that it includes ``the

[[Page 21356]]

use of CCR that does not meet the definition of a beneficial use of 
CCR.'' Waste piles, including those used to temporarily store or manage 
CCR on-site prior to disposal in a CCR landfill or subsequent 
beneficial use, have been retained within the definition of a CCR 
landfill. In making this determination the Agency was strongly 
influenced by the similarities in the potential risks posed by both 
waste piles and CCR landfills to human health, groundwater resources, 
or the air if improperly managed. Both CCR piles and CCR landfills are 
subject to external factors such as rain and wind, which can adversely 
affect human health and the environment. For example, uncontrolled run-
on and run-off can result in ponding of water in and around the unit 
resulting in increased leachate which has the potential to affect 
groundwater. Similarly, absent dust control measures, such as the 
conditioning of CCR, both CCR landfills and CCR piles have the 
potential to generate significant amount of fugitive dust. Indeed, CCR 
piles are generally more susceptible to the creation of fugitive dusts. 
And contrary to the commenters' contention about the absence of damage 
cases, the single most frequent issue presented during the public 
hearings was the allegation by individual citizens of damage caused by 
fugitive dusts from neighboring CCR facilities. Moreover, the same 
pollution control measures, such as liners, leachate collection 
systems, and groundwater monitoring, will address the potential adverse 
effects from both of these units. As such, the Agency sees no reason to 
treat piles and landfills differently.
    EPA also disagrees that the inclusion of CCR piles would capture 
on-going or short-term CCR management activities that do not constitute 
disposal. Irrespective of whether the facility is using the pile as 
``temporary storage'' or ultimately intends to direct the CCR to 
beneficial use, by placing the CCR on the land with no containment or 
other method of preventing environmental exposures, the facility is 
engaging in an activity that clearly falls within the statutory 
definition of disposal. See 42 U.S.C. 6903(3)(``placing of solid waste 
. . . on any land, so that such solid waste . . . or any constituent 
thereof may enter the environment.'') Moreover, even where the facility 
intends the pile to be ``temporary,'' some amount of CCR inevitably 
remains in place. And if this was not the case, under section 
1008(a)(3), EPA is authorized to establish criteria governing all 
aspects of solid waste management--which explicitly is defined to 
include ``storage'' as well as all of the other activities identified 
by the commenters--to ensure the protection of human health and the 
environment. See 42 U.S.C. 6903(28).
    Nevertheless, EPA agrees that not every activity that involves the 
management of CCR must occur in a unit that meets all of the technical 
requirements of a CCR landfill (e.g., groundwater monitoring). The key 
concern EPA is seeking to address with the inclusion of piles is the 
uncontrolled exposure from the extended, repeated, or indefinite 
placement of large amounts of unconsolidated CCR directly on the land. 
To the extent those exposures are controlled, whether through the use 
of tanks or some other kind of containment measures, the practice is 
neither considered to be a ``pile'' nor disposal in a landfill.
    To clarify this, and in response to the concern that the term 
``piles'' was too vague, EPA has adopted a definition of the term ``CCR 
pile'' to identify those ``piles'' that are subject to the disposal 
requirements in this regulation. The final regulation specifies that a 
CCR pile means any non-containerized accumulation of solid, non-flowing 
CCR that is placed on the land. This definition mirrors the existing 
definition of ``waste pile or pile'' from the part 257 regulations, 
(i.e., the regulations that currently apply to CCR facilities), as well 
as the definition in part 260. The use of the phrase ``non-
containerized'' is not intended to require that all activities occur 
within tanks or containment structures, but merely that specific 
measures have been adopted to control exposures to human health and the 
environment. This could include placement of the CCR on an impervious 
base such as asphalt, concrete, or a geomembrane; leachate and run-off 
collection; and walls or wind barriers. CCR managed in such a fashion 
would not be CCR piles and, therefore, not CCR landfills subject to 
this regulation. To further clarify how this relates to EPA's overall 
approach to beneficial use it is important to distinguish between CCR 
that is actually being used beneficially and CCR that may someday be 
used beneficially. CCR that is currently being used beneficially--for 
example, fly ash that has been transferred to a cement manufacturer and 
that is stored off-site in a ``temporary pile,'' and that complies with 
all of the criteria in the definition to be considered a beneficial use 
including the fourth criterion relating to the placement of large 
quantities of unconsolidated CCR on the land--would not be subject to 
the regulations applicable to CCR disposal. Accordingly, the final 
regulation specifies that practices that meet the definition of 
beneficial use of CCR are not subject to the `disposal'' requirements 
of the rule.
    By contrast, CCR located on-site that may someday be used 
beneficially but is not yet beneficially used remains subject to the 
disposal rule. Given that landfills and surface impoundments can be 
periodically dredged to provide material for beneficial use, any other 
approach would be impracticable, and would exclude from regulation many 
of the greatest sources of risk. An example of a ``pile'' that is not 
yet beneficially used is unconsolidated CCR placed on the land, that 
have been designated by the CCR facility to be transferred to another 
location for subsequent beneficial use (e.g., use as road bed) in the 
near future.
    Several commenters also suggested that the definition of a CCR 
landfill should explicitly exclude the use of CCR at surface coal 
mining and reclamation operations, to reflect the Agency's intention 
not to cover such activities. The Agency agrees and has revised the 
definition to explicitly provide that the term CCR landfill does not 
include the use of CCR at coal mining and reclamation operations.
    Consequently, the Agency is finalizing a definition of ``CCR 
landfill or landfill'' that can be found in Sec.  257.73. On a related 
matter, the definition of CCR landfill or landfill contains the terms 
``sand and gravel pits or quarries.'' EPA proposed a ``sand and gravel 
pit and/or quarry'' to mean an excavation for the commercial extraction 
of aggregate for use in construction projects. The Agency received 
comments on the definition of sand and gravel pit and/or quarry 
suggesting that the term ``commercial extraction'' was too narrow. 
Specifically commenters were concerned it would exclude non-commercial 
extraction, such as gravel pits operated by municipalities, and exclude 
metallic mineral mines, nonmetallic mining for other than sand and 
gravel, and coal mines. EPA agrees that the use of the term 
``commercial extraction'' renders the proposed definition too narrow, 
as there is no basis for distinguishing between commercial and non-
commercial extraction, either because of the risks these activities 
pose, or any other consideration relevant to this rulemaking. EPA is, 
therefore, revising ``sand and gravel pit and/or quarry'' to mean an 
excavation for the extraction of aggregate, minerals, or metals. The 
term sand and gravel pit and/or quarry does not include subsurface or 
surface coal mines.

[[Page 21357]]

2. Definition of CCR Surface Impoundment
    EPA proposed to define a CCR surface impoundment to mean a facility 
or part of a facility which is a natural topographic depression, man-
made excavation, or diked area formed primarily of earthen materials 
(although it may be lined with man-made materials) which is designed to 
hold an accumulation of CCR containing free liquids, and which is not 
an injection well. Examples of CCR surface impoundments are holding, 
storage, settling, and aeration pits, ponds and lagoons. CCR surface 
impoundments are used to receive CCR that have been sluiced (flushed or 
mixed with water to facilitate movement), or wastes from wet air 
pollution control devices, often in addition to other solid wastes.
    The Agency received many comments on the proposed definition of CCR 
surface impoundment. The majority of commenters argued that the 
definition was overly broad and would inappropriately capture surface 
impoundments that are not designed to hold an accumulation of CCR. 
Commenters were concerned that the proposed definition could be 
interpreted to include downstream secondary and tertiary surface 
impoundments, such as polishing, cooling, wastewater and holding ponds 
that receive only de minimis amounts of CCR. Commenters reasoned that 
these types of units in no practical or technical sense could be 
described as units ``used to receive CCR that has been sluiced.''
    Other commenters raised concern that the definition did not 
differentiate between temporary and permanent surface impoundments. 
Commenters stated that many facilities rely on short-term processing 
and storage before moving CCR off-site for beneficial use or permanent 
disposal and that these units should not be required to comply with all 
of the technical criteria required for more permanent disposal 
impoundments.
    Upon further evaluation of the comments, the Agency has amended the 
definition of CCR surface impoundment to clarify the types of units 
that are covered by the rule. After reviewing the comments, EPA 
reviewed the risk assessment and the damage cases to determine the 
characteristics of the surface impoundments that are the source of the 
risks the rule seeks to address. Specifically, these are units that 
contain a large amount of CCR managed with water, under a hydraulic 
head that promotes the rapid leaching of contaminants. These risks do 
not differ materially according to the management activity (i.e., 
whether it was ``treatment,'' ``storage'' or ``disposal'') that 
occurred in the unit, or whether the facility someday intended to 
divert the CCR to beneficial use. However, EPA agrees with commenters 
that units containing only truly ``de minimis'' levels of CCR are 
unlikely to present the significant risks this rule is intended to 
address.
    EPA has therefore revised the definition to provide that a CCR 
surface impoundment as defined in this rule must meet three criteria: 
(1) The unit is a natural topographic depression, man-made excavation 
or diked area; (2) the unit is designed to hold an accumulation of CCR 
and liquid; and (3) the unit treats, stores or disposes of CCR. These 
criteria correspond to the units that are the source of the significant 
risks covered by this rule, and are consistent with the proposed rule. 
EPA agrees with commenters that relying solely on the criterion from 
the proposed rule that the unit be designed to accumulate CCR could 
inadvertently capture units that present significantly lower risks, 
such as process water or cooling water ponds, because, although they 
will accumulate any trace amounts of CCR that are present, they will 
not contain the significant quantities that give rise to the risks 
modeled in EPA's assessment. By contrast, units that are designed to 
hold an accumulation of CCR and in which treatment, storage, or 
disposal occurs will contain substantial amounts of CCR and 
consequently are a potentially significant source of contaminants. 
However, EPA disagrees that impoundments used for ``short-term 
processing and storage'' should not be required to comply with all of 
the technical criteria applicable to CCR surface impoundments. By 
``short-term,'' the commenters mean that some portion of the CCR is 
removed from the unit; however, in EPA's experience these units are 
never completely dredged free of CCR. But however much is present at 
any given time, over the lifetime of these ``temporary'' units, large 
quantities of CCR impounded with water under a hydraulic head will be 
managed for extended periods of time. This gives rise to the conditions 
that both promote the leaching of contaminants from the CCR and are 
responsible for the static and dynamic loadings that create the 
potential for structural instability. These units therefore pose the 
same risks of releases due to structural instability and of leachate 
contaminating ground or surface water as the units in which CCR are 
``permanently'' disposed.
    The final definition makes extremely clear the impoundments that 
are covered by the rule, so an owner or operator will be able to easily 
discern whether a particular unit is a CCR surface impoundment. CCR 
surface impoundments do not include units generally referred to as 
cooling water ponds, process water ponds, wastewater treatment ponds, 
storm water holding ponds, or aeration ponds. These units are not 
designed to hold an accumulation of CCR, and in fact, do not generally 
contain significant amounts of CCR. Treatment, storage, or disposal of 
accumulated CCR also does not occur in these units. Conversely, a 
constructed primary settling pond that receives sluiced CCR directly 
from the electric utility would meet the definition of a CCR surface 
impoundment because it meets all three criteria of the definition: It 
is a man-made excavation and it is designed to hold an accumulation of 
CCR (i.e., directly sluiced CCR). It also engages in the treatment of 
CCR through its settling operation. The CCR may be subsequently dredged 
for disposal or beneficial use elsewhere, or it may be permanently 
disposed within the unit. Similarly, secondary or tertiary impoundments 
that receive wet CCR or liquid with significant amounts of CCR from a 
preceding impoundment (i.e., from a primary impoundment in the case of 
a secondary impoundment, or from a secondary impoundment in the case of 
a tertiary impoundment), even if they are ultimately dredged for land 
disposal elsewhere are also considered CCR surface impoundments and are 
covered by the rule. To illustrate further, consider a diked area in 
which wet CCR is accumulated for future transport to a CCR landfill or 
beneficial use. The unit is accumulating CCR, while allowing for the 
evaporation or removal of liquid (no free liquids) to facilitate 
transport to a CCR landfill or for beneficial use. In this instance, 
the unit again meets all three definition criteria, it is a diked area 
(i.e., there is an embankment), it is accumulating CCR for ultimate 
disposal or beneficial use; and it is removing any free liquids, (i.e., 
treatment). As such, this unit would meet the definition of CCR surface 
impoundment. In all of these examples significant quantities of CCR are 
impounded with water under a hydraulic head that will be managed for 
extended periods of time. This gives rise to the conditions that both 
promote the leaching of contaminants from the CCR and are responsible 
for the static and dynamic loadings that create the potential for 
structural instability. These units therefore all pose the same risks 
of

[[Page 21358]]

releases due to structural instability and of leachate contaminating 
ground or surface water.
3. Definition of Existing CCR Landfill
    EPA proposed to define an existing CCR landfill to mean a CCR 
landfill which was in operation on, or for which construction commenced 
prior to the effective date of the final rule. The proposed definition 
specified that a CCR landfill has commenced construction if the owner 
or operator has obtained the federal, state, and local approvals or 
permits necessary to begin physical construction; and either: (1) A 
continuous on-site, physical construction program has begun; or (2) 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 to be completed within a reasonable 
time.
    In response to the proposed definition, the Agency received several 
comments arguing that the use of the phrase ``was in operation on, or 
for which construction commenced prior to'' would lead to confusion. 
Commenters contended that most units defined as CCR landfills at some 
point in time ``were in operation'' and had ``commenced construction'' 
prior to the effective date of the regulation. Commenters claimed that 
this definition would unnecessarily capture thousands of closed 
structural fill projects, including residential properties, commercial 
properties used by small businesses, and many recreational facilities. 
Furthermore, commenters doubted that EPA intended for the rule to cover 
all of these units and urged the Agency to clarify that closed units 
are excluded from the definition of existing CCR landfill.
    Other commenters argued that the proposed definition of existing 
CCR landfill should be modified to include lateral expansions of 
operation units where such an expansion is within the site footprint of 
an area already approved and permitted by the state for the landfill. 
Commenters contended that while the proposed definition included 
undeveloped areas within the footprint of an approved permitted site, 
it also required that the construction be initiated at the site or that 
some type of binding contractual obligation be present. Commenters 
contended that the existence of a contractual obligation unfairly 
subjects undeveloped, yet approved permitted areas to design and 
operating standards for new CCR landfills based merely on the existence 
of a contract to commence construction. Commenters argued that such a 
distinction was arbitrary and capricious and provided no practical 
benefit. Other commenters questioned the usefulness of requiring a 
contractual obligation at all. As written, the commenters argued, that 
the definition was vague, unenforceable, and thus, not protective of 
human health and the environment. Commenters reasoned that there was no 
definitive or generally accepted meaning for the term ``substantial 
loss'' or the term ``reasonable time'' and an owner or operator, 
sensing that these proposed rules may be passed, could sign a contract 
now with minimum predetermined cancellation or modification penalties 
and a contract term of say five years or even longer to avoid the new 
unit requirements, i.e., a composite liner.
    The commenters are correct that EPA did not intend to cover 
inactive landfills under this rule. The Agency agrees that, as drafted, 
the proposed definition could cause confusion. EPA therefore deleted 
the phrase ``was in operation on the effective date of the rule'' and 
has substituted the phrase ``that receives CCR both before and after 
[the effective date of the rule].'' EPA also agrees that the phrase 
``commenced construction prior to the effective date of the rule'' 
could similarly cause confusion. Therefore, the Agency has made a 
similar revision, by adding the phrase ``and receives CCR on or after 
[the effective date of the rule]'' after the phrase ``for which 
construction commenced prior to [the effective date of the rule].'' 
These revisions will clarify which units are covered by the technical 
requirement of the rule and alleviate any confusion. EPA is also making 
conforming modifications to the definition of existing CCR surface 
impoundment.
    EPA disagrees that lateral expansions should be considered to be 
``existing'' based solely on the fact that such an expansion is within 
the site footprint of an area already approved and permitted by the 
state. EPA has frequently distinguished between the types of 
requirements applicable to new and existing units, reasoning that in 
many instances, risk mitigation measures would be adequate such that 
existing units need not wholly retrofit to meet the new ``state of the 
art.'' For new units, however, the balance is generally struck in favor 
of requiring a greater degree of risk prevention, rather than relying 
solely on risk mitigation measures. In determining whether a unit is 
``new'' or ``existing,'' EPA has historically considered that the 
equities lie in favor of considering a unit to be ``existing'' when 
there has been an irretrievable commitment of resources on the part of 
the facility. That has not occurred merely because permits have been 
obtained. While admittedly resources have been committed, at this stage 
modifications to the design and construction of the unit are still 
feasible. Specifically, the critical differences between the 
requirements applicable to new and existing CCR landfills are the type 
of liner that must be installed and the location restrictions that 
apply. Compliance with these requirements can be addressed through 
modifications to the design and construction of the unit, and are 
therefore readily feasible until construction has begun.
    EPA agrees with those commenters who were concerned that the 
phrase, ``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 to be completed 
within a reasonable time,'' is vague and potentially subject to abuse. 
While this phrase has been included in other EPA regulations, those 
regulations operate within a regulatory program overseen by a 
regulatory authority. No similar guarantee exists under these 
regulations. EPA could not discover a definitive or generally accepted 
meaning for the terms ``substantial loss'' or ``reasonable time,'' or 
develop sufficiently objective and determinate criteria for these 
concepts. Consequently, the Agency has decided to remove this provision 
from the definition of existing CCR landfill. EPA is retaining the two 
most important elements of the definition that will effectively 
determine whether the facility has irretrievably committed resources 
such that it would not reasonable to require compliance with all of the 
requirements applicable to new units. Accordingly, a unit will be 
considered to be existing if, first, the owner or operator has obtained 
the federal, state, and local approvals or permits necessary to begin 
physical construction; and second, that a continuous on-site, physical 
construction program has begun (i.e., groundbreaking has occurred). 
Therefore, EPA is finalizing the definition of existing CCR landfill 
that can be found in Sec.  257.53.
4. Definition of Existing CCR Surface Impoundment
    EPA proposed to define an existing CCR surface impoundment to mean 
a surface impoundment which was in operation on, or for which 
construction commenced prior to the effective date of the final rule. 
The proposal also specified that a CCR surface impoundment has 
commenced

[[Page 21359]]

construction if the owner or operator has obtained the federal, state, 
and local approvals or permits necessary to begin physical 
construction; and either: (1) A continuous on-site, physical 
construction program has begun; or (2) 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 to be completed within a reasonable time.
    EPA received many of the same comments on the definition of an 
existing CCR surface impoundment that were received on an existing CCR 
landfill. This included comments requesting clarification that the term 
did not include impoundments that had ceased receiving CCR before the 
effective date of the rule. Commenters also suggested that EPA modify 
the definition to include the phrase that the surface impoundment ``was 
in operation and had not yet ceased receiving CCR prior to the 
effective date of the rule'' to make clear that the definition did not 
encompass units that are no longer receiving CCR on the effective date 
of the rule, even though the unit may not have completed final closure 
prior to the rule's effective date. Commenters reasoned that units no 
longer receiving CCR on the effective date of the rule are not ``in 
operation'' and therefore should not be subject to the standards 
applicable to active units. Commenters also requested that EPA clarify 
that the definition of ``existing CCR surface impoundment'' include 
units that were in operation on the effective date of the rule and that 
periodically dredged out during the operating life of the impoundment. 
Commenters contended that while this may seem self-evident, EPA needed 
to clarify that these impoundments would not be characterized as ``new 
CCR surface impoundments.''
    The Agency is generally conforming the definition of an existing 
CCR surface impoundment to the revised definition of an existing CCR 
landfill. Although inactive CCR surface impoundments are covered by the 
final rule (unlike inactive CCR landfills), EPA decided it would 
provide greater clarity to establish a section specific to inactive CCR 
surface impoundments rather than merely including such units within the 
definition of an existing CCR surface impoundment. As discussed in 
greater detail in Unit VI.A of this document, under Sec.  257.100, any 
CCR surface impoundment that continues to impound CCR and water after 
the effective date of the rule, must either (1) breach, dewater, and 
place a cover on the unit within three years or (2) must comply with 
all of the requirements applicable to existing CCR surface 
impoundments. Without the need to account for inactive CCR surface 
impoundments within the definition, the definitions of ``existing'' 
landfills and surface impoundments should be the same.
    Thus, the Agency has removed the term ``in operation'' from the 
definition and has instead focused on when the surface impoundment 
received or will receive CCR. EPA has also deleted the provision that 
would have allowed a unit to be considered to be ``existing'' based on 
the existence of a contract. Accordingly, for purposes of this rule, a 
CCR surface impoundment will be considered to be ``existing'' if the 
unit received CCR both before and after the effective date of the rule. 
For example, if a CCR surface impoundment received CCR prior to the 
effective date and was in the process of dredging on the effective date 
with the intent of receiving additional CCR after the effective date, 
the unit would still be considered to be an ``existing'' rather than a 
new unit. Conversely, if a unit received CCR prior to the effective 
date and was no longer receiving CCR, this unit would be considered 
``inactive,'' and would only be subject to the technical criteria 
applicable to ``existing'' CCR surface impoundments if they had not 
completed closure within three years. Similarly, if a CCR surface 
impoundment had commenced construction prior to the effective date with 
the intention of receiving CCR on or after the effective date of the 
rule, the unit would be considered an ``existing'' unit only if the 
physical construction program had begun (e.g., groundbreaking had 
occurred) with the appropriate federal, state and local approvals or 
permits in place. But if prior to the effective date of the rule, the 
permits had been obtained but the physical construction of the unit had 
not begun (e.g., groundbreaking had not occurred), the unit would be 
considered ``new'' and would be subject to all the applicable technical 
criteria for new CCR surface impoundments. Therefore, the Agency is 
finalizing the definition of existing CCR surface impoundment that can 
be found in Sec.  257.53.

C. Location Restrictions and Individual Location Requirements

    In the proposed rule, EPA stated that any RCRA subtitle D 
regulation would need to ensure that CCR landfills, CCR surface 
impoundments and all lateral expansions were appropriately sited to 
ensure that no reasonable probability of adverse effects on health or 
the environment from the disposal of CCR would occur. Under the 
subtitle D option, EPA proposed location restrictions for CCR units 
which included requirements relating to the placement of CCR in five 
general locations: (1) Above the natural water table; (2) wetlands; (3) 
fault areas; (4) seismic impact zones; and (5) unstable areas. The 
proposed requirements relied in large measure, on the record EPA 
developed to support the 40 CFR part 258 requirements for MSWLFs and on 
EPA's Guide for Industrial Waste Management (EPA530-R-03-001, February 
2003). EPA also chose to add one additional location restriction that 
would ban the placement of CCR units within two feet of the upper limit 
of the natural water table. This proposed requirement was originally 
included in the proposed rule, Standards for the Management of Cement 
Kiln Dust (64 FR 45631, August 20, 1999) because of the potential 
damage to groundwater caused by the management of cement kiln dust at 
sites located below the natural water table. While the proposed cement 
kiln dust rule has not yet been finalized, EPA extended this reasoning 
to CCR by applying the same location restriction to CCR units. The 
proposed applicability of these location requirements varied depending 
on whether the unit was an existing or new CCR landfill, an existing or 
new CCR surface impoundment, or a lateral expansion of such units. For 
example, for existing CCR landfills, the Agency proposed that only the 
location requirement for unstable areas would apply. By contrast, the 
proposed rule applied all of the location restrictions to new CCR 
landfills and all CCR surface impoundments, both existing and new--an 
approach consistent with RCRA subtitle C and Congressional distinctions 
between the risks presented by landfills and surface impoundments. (See 
75 FR 35198-35199.) This meant that owners or operators would need to 
close existing CCR surface impoundments located less than two feet 
above the natural water table, or for existing CCR units in sensitive 
but not prohibited locations, make a technical demonstration that the 
unit met the requirements of a performance standard that serves as the 
alternative to the location restriction, retrofit the unit so that it 
could meet the performance standard, or close. For those CCR units that 
need to close (i.e., owners or operators that could not make the 
necessary technical demonstrations), EPA proposed that the unit must 
close within five years of the effective date of the rule. If closure 
could not occur within the five year timeframe, the

[[Page 21360]]

Agency proposed allowing for a case-by-case extension for up to two 
more years if the facility demonstrated that there was no alternative 
disposal capacity and no immediate threat to health or the environment.
    EPA proposed not to impose all of the location requirements on 
existing CCR landfills based on the conclusion that CCR landfills pose 
less risk and are structurally less vulnerable than existing CCR 
surface impoundments. EPA also raised concern that a significant number 
of these CCR landfills could be located in areas subject to these 
requirements, (particularly wetlands), which could cause disposal 
capacity shortfalls in certain regions of the U.S., if existing CCR 
landfills in these locations were required to close. Disposal capacity 
shortfalls can pose significant environmental and public health 
concerns based on the potential for significant disruption of solid 
waste management state-wide from the closure of these units. EPA 
concluded that these risks would be greater than the potential risks 
from allowing existing CCR landfills to remain in these locations, 
given that these units would be subject to all of the design and 
operating requirements of the rule. To ensure the accuracy of its 
preliminary conclusions, the Agency requested commenters to provide any 
available information regarding the number of existing CCR landfills 
located in these sensitive areas. The Agency also sought information 
regarding the extent to which CCR landfill capacity would be affected 
by applying all of the location restrictions to existing CCR landfills, 
the extent to which facilities could comply with the proposed 
performance standards, and the costs that would be incurred to retrofit 
existing CCR landfills to meet these standards.
    The Agency received numerous comments in response to the Agency's 
request for additional information regarding the extent to which 
landfill capacity would be affected by applying all the proposed 
subtitle D location restrictions to existing CCR landfills. Commenters 
generally agreed with the Agency that applying the other location 
restrictions to existing CCR landfills would cause a significant 
decrease in disposal capacity across the country, although they did not 
provide any data or information which would support this concern. 
Commenters noted, however, that if existing CCR landfills located in 
these areas were to close, it would greatly complicate operations at 
many utilities. Affected facilities would need to find additional 
disposal capacity, which would require utilities to procure new real 
estate on which to site a new CCR landfill (which may be a significant 
distance from a power plant), obtain a new disposal permit for the CCR 
landfill (which can take an extended period of time), and potentially 
transport significant volumes of CCR great distances to newly-permitted 
facilities. Commenters argued that there was simply no environmental 
basis for causing this level of disruption to utility CCR disposal 
practices.
    EPA received no data or information in response to the Agency's 
request for the costs associated with retrofitting a CCR surface 
impoundment or CCR landfill to meet the demonstrations for existing 
units. Similarly, the Agency received little to no information in 
response to EPA's request for additional information on the location of 
these facilities. Some commenters acknowledged that specific states 
were located in some of these restricted areas but did not provide 
specific information on specific units.
    Overwhelmingly, the issue receiving the most comment was EPA's 
intention to subject existing CCR surface impoundments to all of the 
new location criteria. Commenters contended that subjecting existing 
units to all of the location criteria was a radical departure from the 
location restriction provisions of the existing MSWLF rules on which 
the subtitle D option is based (i.e., existing MSWLFs are only subject 
to the floodplains and unstable areas restrictions) without any 
justification for regulating CCR surface impoundments more stringently 
than existing CCR landfills. Commenters argued that EPA must 
demonstrate that there are increased risks posed by each CCR surface 
impoundments based on its location; otherwise, they claimed, there was 
no justification for EPA to subject CCR surface impoundments to more 
stringent location restrictions. Some commenters suggested that a more 
reasonable approach would be to limit the restrictions for existing CCR 
surface impoundments to unstable areas, consistent with the approach 
proposed for existing CCR landfills. Finally, commenters raised concern 
about the inconsistency between the preamble language and the 
corresponding regulatory text. Specifically, the preamble stated EPA's 
intention to apply all of the location criteria to all CCR surface 
impoundments (existing and new) while the proposed regulatory language 
applied all location criteria only to new CCR surface impoundments and 
lateral expansions.
1. Applicability of the Location Criteria to Existing CCR Surface 
Impoundments
    EPA acknowledges the discrepancies between the preamble language 
and the regulatory text regarding the proposed regulatory language for 
the location restrictions as it applies to existing CCR surface 
impoundments. In the proposed rule, the regulatory language should have 
included, ``all surface impoundments'' as opposed to only ``new surface 
impoundments.''
    EPA disagrees that in order to justify national minimum standards 
applicable to existing CCR surface impoundments, the Agency must 
demonstrate an adverse impact to human health and the environment from 
each individual unit, based on the specific risks posed at each 
location. As an initial matter, it is well established that an agency 
may regulate a class of similarly situated entities through rulemaking, 
rather than on the basis of an individualized assessment of every 
entity that will be subject to the rule. And indeed, Congress 
specifically directed EPA to proceed by rulemaking to establish minimum 
national standards under RCRA sections 1008(a) and 4004(a). Moreover, 
section 4004(a) does not require a demonstration of actual impacts, 
merely that these units present an unacceptable risk of harm. Thus, it 
is sufficient for EPA to establish a factual record demonstrating that 
the specific location restrictions in the final rule are necessary for 
CCR units (landfills and surface impoundments), as a class, to ensure 
that there will be no reasonable probability of adverse effects on 
health or the environment. As discussed in greater detail in the next 
section and in Unit X of the preamble, the factual record supports the 
need for all of the location standards for existing CCR surface 
impoundments imposed by this rule.
    The Agency also rejects the suggestion that EPA establish the same 
location restrictions for both existing CCR landfills and CCR surface 
impoundments. As laid out in the proposal and elsewhere in this final 
rule in greater detail, the risks associated with CCR surface 
impoundments are substantially higher than the risks associated with 
CCR landfills, by approximately an order of magnitude. Surface 
impoundments are utilized by 45 percent of coal-fired power plants and 
in 2000 accounted for disposal of one-third of all CCR generated.\46\ 
Unlike landfills, CCR surface impoundments

[[Page 21361]]

contain slurried residuals that remain in contact with ponded waters 
until closure. In a statewide investigation of impacts to groundwater 
quality from CCR disposal sites, the Wisconsin Department of Natural 
Resources reported that closed sites which originally contained sluiced 
coal-combustion residuals displayed extremely elevated mean arsenic 
levels (as high as 364 [micro]g/l).\47\ The highest contaminant 
concentrations in the study were associated with sluiced CCR residuals. 
In addition, releases of toxic contaminants to surface water and 
groundwater from mostly unlined CCR surface impoundments and ponds are 
a relevant factor in 34 of 40 cases of proven damage to the environment 
(as well as in several cases of ``potential'' damage to the 
environment) from mismanagement of CCR.\48\ In many of these cases, 
effluent discharges from the surface impoundments caused significant 
ecological damage to aquatic life in nearby streams and wetlands. In 
one case, in 2002, the structural stability of a CCR surface 
impoundment was directly compromised by sinkhole development, leading 
to the release of 2.25 million gallons of CCR slurry. In another, an 
unusually weak foundation of ash and silt beneath a CCR surface 
impoundment (i.e., man-made unstable ground) was identified as one of 
several likely factors contributing to the dike failure that in 2008 
resulted in the largest CCR spill in United States history.
---------------------------------------------------------------------------

    \46\ Rowe, C.L., Hopkins, W.A., Congdon, J.D., 2002. 
Ecotoxicological Implications of Aquatic Disposal of Coal Combustion 
Residues in the United States: A Review. Environmental Monitoring 
and Assessment, Vol. 80, pp. 207-276.
    \47\ Zillmer, M. and Fauble, P., 2004. Groundwater Impacts from 
Coal Combustion Ash Disposal Sites in Wisconsin. Waste & Materials 
Management, Wisconsin Department of Natural Resources, PUB-WA 1174 
2004.
    \48\ Cases of damage attributable to disposal of coal combustion 
residuals are summarized in the appendix to the preamble of the 
proposed rule, 75 FR 35230-35239, June 21, 2010, and can be found in 
the RCRA Docket.
---------------------------------------------------------------------------

    Unlike RCRA subtitle C, subtitle D does not explicitly authorize 
EPA to establish different standards for existing and new units, and 
Congress specifically intended subtitle D to address the risks from 
existing, abandoned ``open dumps.'' In the proposed rule preamble, EPA 
explained the rationale for applying these provisions to existing CCR 
surface impoundments, and the commenters have submitted nothing to 
rebut that rationale. Thus, EPA maintains its determination that 
application of the location standards to existing CCR surface 
impoundments is necessary to achieve the standard in section 4004(a). 
Absent these location restrictions, the risk of impacts to human health 
and the environment from releases from CCR units, including from the 
rapid and catastrophic destruction of CCR surface impoundments, sited 
in these sensitive areas would exceed acceptable levels. Given that the 
risks associated with CCR surface impoundments are substantially higher 
than the risks posed by CCR landfills, this is the appropriate 
regulatory course for existing CCR surface impoundments.
    In this rule, EPA is finalizing location restrictions that will 
ensure that CCR units are appropriately sited, that the structure of 
the CCR unit will not be adversely impacted by conditions at the site, 
and that overall there will be ``no reasonable probability of harm to 
human health or the environment'' due to the location of the CCR unit. 
EPA is finalizing different sets of location restrictions depending on 
whether the unit is a CCR landfill or CCR surface impoundment and 
whether it is an existing or new unit. Lateral expansions fall within 
the definitions of new units and are treated accordingly. These 
standards provide minimum national siting and performance criteria for 
all CCR units. The location restrictions under Sec.  257.60 through 
Sec.  257.64 include: (1) Placement above the uppermost aquifer; (2) 
wetlands; (3) fault areas; (4) seismic impact zones; and (5) unstable 
areas. Each of these locations is generally recognized as having the 
potential to impact the structure of any disposal unit negatively and 
as such, increase the risks to human health or the environment through 
structural failures or leaching of contaminants into the groundwater. 
Under the final rule and as proposed, new CCR landfills, existing and 
new CCR surface impoundments, and all lateral expansions will be 
required to comply with all of the location restrictions. Existing CCR 
landfills however, will be subject to only two of the location 
restrictions--floodplains, and unstable areas. As noted in the proposed 
rule, and restated here, existing landfills and surface impoundments 
are already subject to the location standards in subpart A of 40 CFR 
part 257 for floodplains, endangered species and surface waters. The 
final rule does not change this requirement, and so facilities should 
already be in compliance. The Agency is finalizing, as proposed, the 
unstable area location restriction for existing CCR landfills because 
the record clearly shows that failure of CCR units in these areas 
(e.g., due to instabilities in Karst terrains) have and in all 
likelihood would continue, in the absence of the restrictions in the 
final rule, to result in damage caused by the release of CCR 
constituents, affecting both groundwater and surface waters. As the 
Agency stated in the proposed rule, the impacts resulting from the 
failure of CCR units from location instability are of far more concern 
than any disposal capacity concerns resulting from the closure of 
existing CCR units in unstable areas.
    Conversely, and also consistent with the proposed rule, EPA is not 
applying the following location restrictions to existing CCR landfills: 
The requirement to construct a unit with a base located no less than 
1.52 meters (five feet) above the upper limit of the uppermost aquifer, 
as well as the siting restrictions applicable to wetlands, fault areas, 
and seismic impact areas. Existing CCR landfills pose lower risks and 
are structurally less vulnerable than existing CCR surface 
impoundments. In addition, 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 failure of the CCR landfills in these locales.
2. Placement Above the Uppermost Aquifer
    Under Sec.  257.60(a) EPA is requiring new CCR landfills, existing 
and new CCR surface impoundments and all lateral expansions to be 
constructed with a base that is located no less than 1.52 meters (five 
feet) above the uppermost aquifer, or to demonstrate that there will 
not be an intermittent, recurring, or sustained hydraulic connection 
between any portion of the base of the CCR unit and the uppermost 
aquifer due to normal fluctuations in groundwater elevations (including 
groundwater elevations during the wet season). Existing surface 
impoundments that fail to achieve this standard must close. New CCR 
landfills, new CCR surface impoundments and all lateral expansions of 
existing and new CCR landfills and CCR surface impoundments cannot be 
constructed unless they meet one of these two standards. In response to 
comment, the Agency has modified the criteria in two ways. First, EPA 
has replaced ``a base that is located a minimum of two feet above the 
upper limit of the natural water table'' with ``a base no less than 
1.52 meters (five feet) above the uppermost aquifer.'' EPA received 
comment explaining that fluctuations in groundwater levels in many 
geological settings can exceed ten feet over the course of the year, 
and alleging that the proposed two foot minimum buffer between the base 
of the unit and the top of the water table would therefore be 
insufficiently protective. The

[[Page 21362]]

commenter recommended that the minimum vertical separation be at least 
three to five feet from the base of the liner components. After 
additional research, EPA is finalizing a minimum buffer of five feet 
instead of two feet. EPA's research confirmed the commenter's claims. 
In addition, EPA determined that several states consider five feet 
between the base of the surface impoundment and the top of the 
uppermost aquifer to be the minimum distance that is protective of 
human health and the environment. These are California, Michigan, 
Nebraska, New York, West Virginia, and Wisconsin. The Agency has 
concluded from geographic and climatic spacing of these states that the 
hydrogeologic conditions within them encompass the range of conditions 
found in the United States. Therefore, EPA is finalizing a minimum 
buffer of five feet instead of two feet.
    EPA is also clarifying the definition of the natural water table. 
As some commenters noted, there are many factors (hydrologic and 
geologic settings, nearby pumping, etc.) that influence the location of 
the groundwater table making it difficult to determine the ``natural'' 
level. In addition, as noted, local site-specific hydrogeologic 
conditions within the aquifer may cause the natural groundwater table 
to exceed five feet and vary as much as ten feet. To account for the 
possibility of such large seasonal fluctuations, EPA is revising the 
definition of ``uppermost aquifer'' to specify that the measurement of 
the upper limit of the aquifer must be made at a point nearest to the 
natural ground surface to which the aquifer rises during the wet 
season. This definition of ``uppermost aquifer'' will encompass large 
seasonal variations, and is a more appropriate parameter than 
``seasonal high groundwater table'' as suggested by several commenters 
and the proposed ``natural water table'' because it is more clearly 
defined.
    In Sec.  257.60(a) the term uppermost aquifer has the same 
definition as under the general provisions of Sec.  257.40: The 
geologic formation nearest the natural ground surface that is an 
aquifer, as well as lower aquifers that are hydraulically 
interconnected with this aquifer within the facility's property 
boundary. This definition includes a shallow, deep, perched, confined 
or unconfined aquifer, provided it yields usable water. Although EPA 
originally proposed that all CCR surface impoundments be located ``. . 
. . above the upper limit of the natural water table'', the Agency is 
amending this requirement and replacing ``water table'' with 
``uppermost aquifer'' to make it consistent with the way natural 
underground water sources are described elsewhere in the rule. EPA made 
a second revision to the criteria that were originally proposed. As an 
alternative to requiring that the CCR units described in this section 
be constructed with a base that is located no less than five feet above 
the uppermost aquifer, owners and operators may instead demonstrate 
that there will not be an intermittent, recurring, or sustained 
hydraulic connection between any portion of the base of the CCR unit 
and the uppermost aquifer due to normal fluctuations in groundwater 
elevations (including groundwater elevations during the wet season).
    This alternative standard was developed in response to concerns 
from commenters that a single depth to the aquifer failed to account 
for the wide variations in the level of water table fluctuations in 
different regions of the country. For example, arid regions of the 
country, such as Arizona, under normal conditions generally do not 
experience the same degree of fluctuations in groundwater elevations as 
more temperate regions, such as Minnesota. Accordingly, EPA developed 
an alternative performance standard focused on the conditions 
identified in the damage cases and the risk assessment that this 
location criterion was designed to prevent: Specifically, where the 
groundwater elevation is high enough to intersect the base of the waste 
management unit. In such situations, this hydraulic connection can 
enhance the transport of contaminants of concern from the CCR unit into 
groundwater. By requiring owners and operators to ensure that these 
conditions do not occur, the alternative standard to allow owners and 
operators to account for situations where there are relatively small 
variations in groundwater levels and a buffer of five feet is not 
necessary. This will also ensure that a CCR unit need not address 
situations where an infrequent, unexpected event (e.g., hurricane) 
could cause a brief, temporary condition where the uppermost aquifer 
rises to less than the prescribed five feet but which would not in and 
of itself constitute a long-term threat to the aquifer. However, where 
normal fluctuations in groundwater elevation (including, but not 
limited to, seasonal or temporal variations, groundwater withdrawal, 
mounding effects,\49\ etc.) will result in the failure of the unit to 
meet the performance standard (i.e., no intermittent, recurring, or 
sustained hydraulic connection between the base of the CCR unit and the 
uppermost aquifer), the unit must close.
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    \49\ A phenomenon usually created by the recharge of groundwater 
from a manmade structure, such as a surface impoundment, into a 
permeable geologic material, resulting in outward and upward 
expansion of the free water table. Mounding can alter groundwater 
flow rates and direction; however, the effects are usually localized 
and may be temporary, depending upon the frequency and duration of 
the surface recharge events.
---------------------------------------------------------------------------

    In some recent damage cases, placement of large volumes of CCR into 
highly permeable strata in the disposal area promoted CCR-water 
interactions. For example, from 1995 to 2006 in Anne Arundel County, 
Maryland 4.6 million tons of CCR were placed directly in two sand and 
gravel quarries without a geomembrane liner or leachate collection 
system. Rainwater infiltration into exposed CCR coupled with 
groundwater-CCR interactions and the transmissivity characteristics of 
local strata contributed to rapid migration of heavy metals, including 
antimony, arsenic, cadmium, nickel, and thallium to residential 
drinking water wells located near the mine pits and significant 
deterioration of water quality as a result of placement of CCR. 
Similarly, from 1980 to 1997 in Lansing, Michigan, around 0.5 million 
tons of coal ash was dumped for disposal into a gravel pit with an 
elevated water table. A remedial investigation has established that 
groundwater mounding has immersed the CCR into the upper aquifer 
resulting in on-site exceedances of groundwater quality protection 
standards for sulfate, manganese, lead, selenium, lithium, and boron. 
Placement of CCR into un-engineered, unlined units in permeable strata 
has plainly led to adverse impacts to groundwater. The phrase ``normal 
fluctuations'' has been used to clarify that EPA does not intend for 
the facility to account for extraordinary or highly aberrant conditions 
(e.g., one-in-a million or ``freak'' events). Normal fluctuation can 
include those resulting from natural as well as anthropogenic sources. 
Natural sources that could affect groundwater levels include, but are 
not limited to precipitation, run-off, and high river levels. 
Anthropogenic sources that could affect groundwater levels include 
groundwater withdrawal, pumping, well(s) abandonment, and groundwater 
mounding. In satisfying this location restriction, it may be necessary 
for a professional engineer to model these effects before he can make 
the necessary certifications.\50\ EPA also

[[Page 21363]]

notes that this modeling may include the same considerations already 
evaluated under some state programs.\51\ EPA expects that owners and 
operators will have sufficient information to determine whether their 
CCR unit meets either performance standard. Most, if not all, of this 
information would be information a facility would typically have as 
part of normal operations (e.g., the depth of the CCR unit itself), or 
that will be developed as part of implementing other rule requirements. 
For example, through the groundwater monitoring system required under 
Sec. Sec.  257.90-257.98, the facility can obtain water level 
measurements in a sufficient number of locations (e.g., monitoring 
wells, piezometers) to use in determining whether they satisfy either 
performance standard. Similarly, under Sec.  257.91 a thorough 
characterization of the geology and hydrogeology of the site must be 
conducted. Finally, EPA notes that available technology and guidance 
are available for using existing groundwater monitoring wells, like 
those required under this final rule, to measure groundwater 
levels.\52\
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    \50\ For example, evaluations can be done to estimate 
groundwater mounding such as pubs.usgs.gov/sir/2010/5102/, 
www.groundwatersoftware.com/calculator_9_hantush_mounding.htm, and 
www.ndwrcdp.org/documents/wu-ht-02-45/wuht0245_electronic.pdf.
    \51\ See, e.g., dnr.wi.gov/topic/stormwater/standards/gw_mounding.html.
    \52\ See, e.g., U.S. EPA (Environmental Protection Agency). 
2013. Groundwater Level and Well Depth Measurement. SESDPROC-105-R2. 
Region 4. Athens, GA. Available online at: www.epa.gov/region4/sesd/fbqstp/Groundwater-Level-Measurement.pdf.
---------------------------------------------------------------------------

3. Wetlands
    In Sec.  257.61 of this rule, EPA is finalizing the regulatory text 
essentially as proposed. Specifically, EPA is adopting a prohibition on 
locating all CCR surface impoundments and new CCR landfills, as well as 
lateral expansions of existing CCR units, in wetlands as defined in 40 
CFR 232.2, absent specific demonstrations made by the owner or operator 
that ensure the CCR unit will not degrade sensitive wetland ecosystems. 
These provisions place the burden of proof for these demonstrations 
directly on the owner or operator (the discharger). The owner or 
operator must make the results of these demonstrations available in the 
facility record. Failure to make any of the demonstrations will bar 
siting of the CCR unit in a wetland.
    In 2003, disposal of CCR in natural or man-made aquatic basins 
accounted for nearly one-third of all CCR land disposal. Historically, 
aquatic disposal of CCR has been attractive economically to facilities 
because of its lower overall cost relative to dry management and the 
ease of handling of residuals. During aquatic disposal, CCR is commonly 
piped as a slurried mixture to surface impoundments designed to retain 
the solids in contact with water for the life of the unit. Particulate 
solids from the waste stream gravitationally settle while clarified 
waters ultimately discharge into nearby streams and wetlands.
    The term `wetlands' refers to those areas inundated or saturated by 
surface or groundwater at a frequency and over a duration sufficient to 
support a prevalence of vegetation typically adapted for life in 
saturated soil conditions. Wetlands include marshes, swamps, bogs and 
similar areas that are commonly located between open water and dry 
land. Under the CWA, wetlands are considered 'special aquatic sites' 
deserving of special protection because of their ecologic significance. 
Wetlands are very important, fragile ecosystems that must be protected, 
and EPA has long identified wetlands protection as a high priority.
    Undisturbed, natural wetlands provide many benefits to society by 
improving water quality, providing essential breeding, rearing, and 
feeding grounds for fish and wildlife, reducing shoreline erosion, and 
absorbing flooding waters and pollution. Wetlands are also commercial 
source areas of products for human use such as timber, fish, and 
shellfish. Recreational hunters harvest wetland-dependent waterfowl. 
Wetland environments, however, may be adversely impacted by releases of 
wastes from co-located industrial facilities. Wetland ecosystems can be 
degraded by accidental discharges that can change the habitat value for 
fish and wildlife by obstructing surface water circulation patterns, 
altering substrate elevation, dewatering, or permanent flooding.
    In support of the provisions finalized in this rule, EPA is citing 
several damage cases, including 30 cases of ``proven'' damage to the 
environment that involve aquatic disposal of CCR, 14 of which involve 
impacts to wetlands from release of CCR. For example, at the Hyco 
Reservoir in Roxboro, North Carolina from 1966 to 1990 the lake 
received contaminated effluent from coal ash disposal basins that were 
authorized by National Pollutant Discharge Elimination System (NPDES) 
permits under the CWA. High levels of the trace element selenium 
bioaccumulated in aquatic food chains (phytoplankton), poisoning 
invertebrates and fish in the lake, particularly species of sport fish 
(bluegill, largemouth bass), causing reproductive failure and severe 
declines in fish populations in the late 1970's and early 1980's. 
Consequently, from 1988-2001 the North Carolina Department of Health 
and Human Services (NCDHHS) issued a consumption restriction advisory 
for selenium contamination in fish from the reservoir. In 1990, a dry 
ash handling system was implemented resulting in lower selenium 
discharge and reduced mean selenium concentration in reservoir waters. 
As of 2005, concentrations of selenium in fish tissues remained above a 
toxic threshold even with reduced influx of selenium, due to migration 
of the element from contaminated sediments to benthic food chains. The 
total monetized value of damage can be divided among ecologic factors 
(e.g., major impacts on fish), recreational factors (e.g., fishing 
trips not taken), depreciated real estate values, aesthetic factors, 
and human health damages (e.g., losses due to stress and anxiety from 
knowing ecosystem is poisoned) and is estimated at $877 million.\53\
---------------------------------------------------------------------------

    \53\ Lemly, A.D. 2010. Op.cit.
---------------------------------------------------------------------------

    Although this consideration is not relevant for purposes of 
establishing the minimum national criteria under RCRA sections 1008(a) 
and 4004(a), the rulemaking record demonstrates that the monetary cost 
of environmental damage from releases of CCR at surface impoundments 
could be considerable. A report on the environmental damage caused by 
releases of CCR at 22 sites estimates the total cost of poisoned fish 
and wildlife at the surface impoundment sites at $2.32 billion. At 
twelve of these sites the releases were legally permitted under the 
CWA. Five of the 22 cases were caused by structural failures, two 
resulted from an unpermitted discharge, and one was from a 
landfill.\54\ Effluent contaminated with coal combustion residues is 
directly linked with high loadings of toxic metals in the discharge 
areas of aquatic basins, where some metals (primarily arsenic, cadmium, 
chromium, copper, lead, and selenium) have accumulated in aquatic food 
chains.\55\ In a research overview (literature synthesis) on the 
environmental effects of disposal of CCR, Rowe et al. (2002) listed 
adverse biological responses, including histopathological, behavioral, 
and physiological (reproductive, energetic, and endocrinological) 
effects, that have been observed in some vertebrates and invertebrates 
following exposure to and bioaccumulation of CCR-related contaminants.
---------------------------------------------------------------------------

    \54\ Lemly, A.D.2010. Op. cit.
    \55\ Rowe, C.L. et. al. 2002. Op. cit.
---------------------------------------------------------------------------

    Under the criteria finalized in this rule, in order to locate a CCR 
unit or

[[Page 21364]]

lateral expansion in a wetland, the owner or operator must: (1) 
Successfully rebut the presumption that an alternative site (i.e., one 
that does not involve a wetland) is reasonably available for the CCR 
unit or lateral expansion; (2) 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 protection of a marine sanctuary; (3) show that the CCR 
unit or lateral expansion will not cause or contribute to significant 
degradation of wetlands; and (4) demonstrate that steps have been taken 
to attempt to achieve no net loss of wetlands.
    In addition to these requirements, other federal laws may be 
applicable in siting a CCR unit in a wetland. These include: Sections 
401, 402, and 404 of the CWA; the Rivers and Harbors Act of 1989; the 
National Environmental Policy Act; the Migratory Bird Conservation Act; 
the Fish and Wildlife Coordination Act; the Coastal Zone Management 
Act; the Wild and Scenic Rivers Act; and the National Historic 
Preservation Act. In addition, the use of a wetlands location for a CCR 
unit may require a permit from the U.S. Army Corps of Engineers. To the 
extent these are applicable, compliance with these RCRA criteria does 
not alleviate the need to comply with these other federal requirements, 
and the owner or operator of the facility remains responsible for 
ensuring compliance with all applicable federal and state requirements.
    The rule adopts a regulatory presumption that a less damaging 
alternative to locating a disposal unit in a wetland exists, unless the 
owner or operator can demonstrate otherwise. Thus, when proposing to 
locate a new facility or lateral expansion in a wetland, owners and 
operators must be able to demonstrate that alternative sites are not 
available and that the impact to wetlands is unavoidable. If this 
presumption is not clearly rebutted, then the CCR unit may not be sited 
in a wetland location. Such an analysis necessarily includes a review 
of reasonable alternatives to locating or laterally expanding CCR units 
in wetlands. As part of the evaluation of reasonable (that is, 
available and feasible) alternatives the owner or operator must show, 
and a qualified professional engineer must verify, that operation or 
construction of the CCR unit will not: (1) Violate any applicable state 
water quality standards; (2) cause or contribute to the violation of 
any applicable toxic effluent standard or prohibition; (3) cause or 
contribute to violation of any requirement for the protection of a 
marine sanctuary; and jeopardize the continued existence of endangered 
or threatened species or critical habitats.
    When evaluating the impacts of a CCR unit on a wetland, the owner 
or operator must ensure that the unit cannot cause or contribute to 
significant wetland degradation. Therefore, the owner or operator and 
the qualified professional engineer must: (1) Verify the integrity of 
the CCR unit, and its ability to protect ecological resources by 
addressing the erosion, stability, and migration potential of native 
wetland soils, and dredged and fill materials used to support the unit; 
(2) verify that the design and operation of the CCR unit minimizes 
impacts on fish, wildlife, and other aquatic resources and their 
habitat(s) from any release of coal combustion residuals; (3) evaluate 
the effects of catastrophic release of CCR to the wetland and the 
resulting impacts on the environment; and (4) verify that ecological 
resources in the wetland are sufficiently protected, including 
consideration of the volume and chemistry of the CCR managed in the 
unit; and any additional factors, as necessary.
    When a wetland functions properly, it provides water quality 
protection, fish and wildlife habitat, natural floodwater storage, and 
reduction in the erosive potential of surface water. A degraded wetland 
is less able to effectively perform these functions. For this reason, 
wetland degradation is as big a problem as outright wetland loss, 
though often more difficult to identify and quantify. Any change in 
hydrology can significantly alter the soil chemistry and plant and 
animal communities. The common hydrologic alterations that can lead to 
significant degradation in wetland areas include: (1) Deposition of 
fill material, including CCR; (2) drainage for development; (3) 
dredging and stream channelization for development; (4) diking and 
damming to form ponds or impoundments; (5) diversion of CCR-bearing 
waters or other flows to or from wetlands; (6) addition of impervious 
surfaces in the watershed, thereby increasing water and CCR-bearing 
run-off into wetlands. These activities can mobilize CCR-bearing 
sediment; and once the sediment is discharged into the environment, 
toxic metals in CCR can become available to organisms within the 
wetland. Consequently, while the mere presence of one or more of these 
activities does not necessarily demonstrate that the CCR unit causes or 
contributes to significant degradation, the fact that they may do so 
means these activities need to be carefully evaluated.
    In determining what constitutes ``significant'' degradation, it is 
important to understand that although wetlands are capable of absorbing 
pollutants from the surface water, there is a limit to their capacity 
to do so. For the purposes of this rule, the primary pollutants of 
concern are CCR-bearing sediment and toxic metals. Although the risk 
assessment did not assess the exposure and hazard to wetlands, these 
can originate from uncontrolled run-off from the facility, fugitive 
dust from uncovered CCR landfills and piles, and uncontrolled discharge 
from CCR units (landfills, waste piles, surface impoundments). A clear 
example of biologically significant degradation in wetlands is when 
these toxic metals accumulate in benthic and aquatic food chains as a 
result of uncontrolled runoff. Another is obrution (smothering) of 
benthic organisms from discharge(s) of CCR to surface water, thereby 
jeopardizing the continued existence of organisms or critical habitats 
within the wetland. EPA notes that there are other requirements 
established under this rule that can also be relevant in this context, 
as they have the potential to reduce the likelihood that facility 
operations will cause or contribute to significant wetland degradation. 
EPA anticipates that as the facility begins to implement all of the 
requirements under this rule, the facility will consider how 
modifications to facility operations to address one requirement can 
affect compliance with other requirements.
    After consideration of these factors, if an existing CCR unit 
cannot meet all of the requirements in paragraphs (1)-(3) (i.e., if it 
causes or contributes to significant degradation, or if no reasonable 
alternative to locating a new CCR unit in wetlands is available), the 
facility can comply with the location criterion by compensatory steps 
that must be taken to achieve no net loss of wetlands (as defined by 
acreage and function). Owners or operators must first take measures to 
avoid impacts to wetlands. If potential impacts cannot be avoided, all 
reasonable steps are to be taken to minimize such impacts to the extent 
feasible. Appropriate measures (for example, engineered containment 
systems to control discharge of leachate or surface water run-off to 
wetlands) will likely be site-specific and should be incorporated into 
the design and operation of the CCR unit. Any remaining unavoidable 
impacts must be offset, or compensated for through all appropriate and 
feasible compensatory mitigation actions. This compensatory

[[Page 21365]]

mitigation may take the form of restoration (re-establishment or 
rehabilitation of a wetland), establishment (creation of a man-made 
wetland where one did not previously exist), enhancement (improving one 
or more wetland functions), and preservation (permanent protection of 
important wetlands through implementation of appropriate legal and 
physical mechanisms). The functions and values of a wetland will vary 
based on any number of site specific characteristics, including 
location, wetland type, hydrology, degradation, and whether it is 
natural or constructed to treat waste. Strictly limited to the 
application of the wetlands location requirements under this rule, any 
assessment of the nature and extent of mitigation required under the 
CCR rule shall consider these kinds of characteristics, including 
wetlands designed for the treatment of CCR. The Agency recognizes that 
the function and value of a particular man-made wetland constructed to 
perform a wastewater treatment function may present a unique situation 
that may affect both the determination of whether the wetland is 
significantly degraded, and the nature and extent of any required 
compensatory mitigation. This discussion refers only to the wetlands-
related requirements of this rule and does not affect any requirements 
or obligations under the Federal Water Pollution Control Act (33 U.S.C. 
1251, et seq.) and its implementing regulations.
    Although EPA is not finalizing an outright ban on siting of 
existing or new CCR units in wetlands, the Agency continues to believe 
that discharges to wetlands of pollutants that can be reasonably 
avoided should be avoided. Therefore, the amount and quality of 
compensatory mitigation may not substitute for avoiding and minimizing 
impacts. For purposes of this rule, EPA assumes CCR units that are 
designed to avoid discharge of CCR into wetlands have less adverse 
impact to the aquatic environment than CCR units that ultimately 
discharge such residuals in wetlands.
4. Fault Areas
    In Sec.  257.62 of this rule, EPA is banning the location of new 
CCR landfills, existing and new CCR surface impoundments, and all new 
lateral expansions within 60 meters (200 feet) of a fault that has had 
displacement in Holocene time, unless the owner or operator 
demonstrates that an alternative setback distance of less than 60 
meters (200 feet) will prevent damage to the structural integrity of 
the unit. For existing surface impoundments, the demonstration is 
required only if the unit is located closer than 60 meters (200 feet) 
to an active Holocene fault. If a demonstration cannot be made, the 
existing surface impoundment must close. These requirements have been 
adopted with only minor changes from the proposal, and will minimize 
the risks associated with CCR units located in fault areas.
    Stresses produced during earthquake motion can cause serious damage 
to landfill integrity via seismically induced ground failure and 
associated rupture of liner systems and subsequent damage to leachate 
collection systems. Or if the unit is unlined, seismic motion could 
disrupt landfill caps and foundation soils that impede migration of 
percolating water. Potential damage to CCR units resulting from 
structures located across a fault include surface breakage, cracks and 
fissures between fill and confining slopes, slope failure via 
landslides, liquefaction-induced lateral spreading and settlement of 
the pile, disruption of surface water and drainage control systems, and 
rupture of leachate collection systems. In impoundments, for example, 
interior dike failure and leakage, and rupture of multilayer liner 
systems would also be of concern. Failure of the leachate collection 
system may prevent removal of generated leachate, allowing it to pond 
on the liner. If the liner system is ruptured, this may create a 
pathway for leachate to migrate into and contaminate the uppermost 
aquifer. In addition to the potential damage to leachate collection and 
liner systems, the integrity of the landfill slopes could also be 
impaired by fault rupture, potentially exposing coal combustion 
residuals to surface run-off.
    The best protection is to avoid locating new CCR landfills and all 
CCR surface impoundments across faults and fault zones subject to 
displacement. For new units or lateral expansions there is no need to 
construct units in these areas. For existing surface impoundments, the 
Agency has been unable to find any way to retrofit or engineer the unit 
to be protective. A setback distance of 60 meters (200 feet) from the 
outermost damage zone of a Holocene fault will provide an adequate 
margin of safety to protect the facility from displacements due to 
surface faulting and any associated damage because 60 meters typically 
covers the zone of deformation where the ground may be bent or warped 
as a consequence of fault movement. By including this as a siting 
requirement for new units the risk of rupture of the unit, including 
any liner and leachate collection systems, due to surface faulting will 
be minimized.
    Observations of engineered landfill response during earthquake 
motion come primarily from California where field data have been 
reported from MSWLFs (including some meeting the current part 258 
standards) affected by strong shaking from six major nearby 
earthquakes. In these large magnitude events (M >= 6.7), bedrock peak 
horizontal ground accelerations, an index of the intensity of 
earthquake motion, endured by the landfills were in excess of 0.3g. 
Engineered dry MSWLFs in California are reported to have performed well 
after strong earthquake motion (no documented incidence of an 
earthquake-induced release of contaminants harmful to human health or 
to the environment). Minor cracking of cover soils and breaking of 
vertical wells and headers were among the most common types of damage 
reported at MSWLFs subject to strong ground shaking. In the 1994 
Northridge earthquake, only one landfill compliant with RCRA Part 258 
standards experienced tears in a liner (a geomembrane liquid barrier): 
One tear 23 meters in length. However, there is little data on seismic 
stability and performance from industrial solid waste landfills with 
geosynthetic liners or units with water-saturated CCR waste. The 
Agency, therefore, remains concerned over the potential instability of 
engineered disposal units, and particularly CCR surface impoundments, 
under seismic loadings. Accordingly, EPA is prohibiting new CCR 
landfills, CCR surface impoundments, and any new extensions from sites 
located within an active fault zone, unless the owner or operator makes 
a demonstration, certified by a qualified professional engineer, that 
an alternative setback distance of less than 60 meters will prevent 
damage to the structural integrity of the unit.
    EPA is clarifying its definition of fault to incorporate updated 
technical information.\56\ Although a fault can be thought of as a 
simple planar surface across which there has been measurable 
displacement of one side relative to the other, field-based 
observations show fault architecture to often be complex. In the 
geologic literature faults developed in the upper crust are 
characterized as zones of brittle deformation composed of linked fault 
segments, with each segment composed of one or more subparallel, 
curved, or anastomosing fault cores nested within

[[Page 21366]]

a damage zone. Some fault zones may contain broad deformational 
features such as pressure ridges and sags rather than clearly defined 
fault scarps or shear zones.\57\ Fault cores are regions of high strain 
slip that have accommodated most of the displacement and are marked by 
mylonites, cataclastites, and gouge, whereas the damage zone is 
characterized by low strain structures mechanically related to the 
growth of the fault zone such as small faults, fractures, veins and 
folds. To avoid displacement that would damage unit integrity, it is 
best to restrict new CCR landfills and surface impoundments, and all 
new extensions, to locations no less than 60 meters from the outermost 
damage zone created by an active fault. Fault zones can range from one 
meter to several kilometers in width.
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    \56\ Sibson, R.H. 2003. Thickness of the Seismic Slip Zone. 
Bulletin of the Seismological Society of America, Vol. 93, No. 3, 
pp. 1169-1178.
    \57\ Bryant, W.A. and Hart, E.W., 2007. Fault-Rupture Zones in 
California. Special Publication 42 (Interim Revision), California 
Division of Mines and Geology, Sacramento, California.
---------------------------------------------------------------------------

    For purposes of this section, a fault is considered active if it 
has moved during Holocene time. Holocene time is defined as the 
geological epoch which began at the end of the Pleistocene, at 11,700 
years BP (before present), and continues to the present. In the field, 
evidence for Holocene activity may be hard to obtain. Therefore, the 
Agency cautions that faults which show no evidence for Holocene 
activity may not necessarily be inactive.
    To investigate active faults, EPA expects owners and operators of 
CCR units to follow standard engineering and geologic practices. 
Technical considerations include: (1) A geologic reconnaissance of the 
site to determine the location of active faults. Such a reconnaissance 
would include utilizing the seismic analysis maps and tools (Quaternary 
fault maps, earthquake probability maps) of the United States 
Geological Survey (USGS) Earthquake Hazards Program (http://earthquake.usgs.gov/hazards/apps/); and (2) a site fault 
characterization within 1000 meters of a site to determine whether it 
is within 60 meters of an active fault. Such characterizations would 
include subsurface exploration, including drilling or trenching, to 
locate any fault zones and evidence of faulting, trenching 
perpendicular to any faults or lineaments found within 60 meters of the 
site, and determination of the age of any displacements. Based on this 
information, the qualified professional engineer would prepare a report 
that delineates the location of any active (Holocene) fault, including 
any damage zones, and the associated 60 meter setback. To take 
advantage of an alternative setback distance of less than 60 meters, 
the owner or operator must make a demonstration, certified by a 
qualified professional engineer, that the CCR landfill, surface 
impoundment, or lateral expansion has a foundation or base capable of 
providing support for the structure, and capable of withstanding 
hydraulic pressure gradients to prevent failure due to settlement, 
compression, or uplift, and all effects of ground motions resulting 
from at least the maximum surface acceleration expected from a probable 
earthquake.
5. Seismic Impact Zones
    In Sec.  257.63, EPA is adopting the provisions applicable to 
seismic impact zones, as proposed. The rule prohibits new CCR 
landfills, existing and new CCR surface impoundments and all lateral 
extensions from being located in seismic impact zones unless the owner 
or operator makes a demonstration, certified by a qualified 
professional engineer, that all containment structures, including 
liners, leachate collection systems, and surface water control systems, 
are designed to resist the maximum horizontal acceleration in lithified 
earth material from a probable earthquake. A Seismic impact zone means 
an area having a 2% or greater probability that the maximum expected 
horizontal acceleration, expressed as a percentage of the earth's 
gravitational pull (g), will exceed 0.10 g in 50 years. Seismic zones, 
which represent areas of the United States with the greatest seismic 
risk, are mapped by the U.S. Geological Survey and readily available 
for all the U.S. (http://earthquake.usgs.gov/hazards/apps/).
    Maximum Horizontal Acceleration in lithified earth material means 
the maximum expected horizontal acceleration at the ground surface as 
depicted on a seismic hazard map, with a 98% or greater probability 
that the acceleration will not be exceeded in 50 years, or the maximum 
expected horizontal acceleration based on a site-specific seismic risk 
assessment. This requirement translates to a 10% probability of 
exceeding the maximum horizontal acceleration in 250 years.
    For units located in seismic impact zones, as part of any 
demonstration, owners and operators should include: (1) A determination 
of the expected peak ground acceleration from a maximum strength 
earthquake that could occur in the area; (2) a determination of the 
site-specific seismic hazards such as soil settlement; and (3) a 
facility design that is capable of withstanding the peak ground 
acceleration. Seismic designs broadly should include a response 
analysis to quantify the demands of earthquake motion on facility 
structures (i.e., landfills, surface impoundments, liners, covers, 
leachate collection systems, surface water handling systems), 
liquefaction analyses of both waste and foundation soils to evaluate 
stability under seismic loading, and a slope stability and deformation 
analyses. Design modifications to accommodate seismic risks should 
include use of conservative design factors, use of ductile materials, 
built-in redundancy for critical system components, and other measures 
capable of mitigating the potential for seismic upset.\58\
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    \58\ The seismic location standard requires a demonstration that 
a CCR disposal unit can withstand the stresses imposed by peak 
ground acceleration during earthquake motion. The seismic factor of 
safety is a unitless measure of strength calculated for fill 
material assuming earthquake conditions. It is the ratio of material 
shear strength relative to the magnitude of shear forces acting on 
the material. For a CCR disposal unit, the seismic location 
demonstration could be composed of numerous factor of safety 
calculations showing that the structural components of the unit have 
factors of safety greater than or equal to 1.00.
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    Following trends in earthquake engineering, seismic design criteria 
for new CCR landfills, new CCR surface impoundment and all lateral 
expansions should be based on a ``withstand without discharge'' 
standard.\59\ EPA interprets the performance standard in this criterion 
(``designed to resist the maximum horizontal acceleration in lithified 
earth material from a probable earthquake'') to require any new CCR 
unit located in a seismic impact zone to be designed to withstand 
seismic motion from a credible earthquake without damage to the 
foundation or to the structures that control leachate, surface 
drainage, or erosion. In other words, the CCR unit must be able to 
withstand an expected earthquake without discharging waste or 
contaminants. The owner or operator must make a demonstration, 
certified by a qualified professional engineer, that the CCR unit has a 
foundation or base capable of providing support for the structure, and 
capable of withstanding hydraulic pressure gradients to prevent failure 
due to settlement, compression, or uplift and all effects of ground 
motions resulting from at least the maximum surface acceleration 
expected from a probable earthquake. In practice, the Agency recognizes 
that the CCR unit may sustain some limited damage during an earthquake, 
but ultimately, the CCR unit design must remain

[[Page 21367]]

capable of preventing harmful release of CCR, leachate, and 
contaminants both during and after the seismic event.
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    \59\ Kavazanjian, E., 1999. Seismic Design of Solid Waste 
Containment Facilities. Proceedings of the Eight Canadian Conference 
on Earthquake Engineering Vancouver, BC, pp. 51-89.
---------------------------------------------------------------------------

6. Unstable Areas
    EPA laid out its rationale for these requirements in the proposal 
at 75 FR 35201. No significant comments were received on either this 
rationale or the specific regulatory provisions. Consequently, EPA is 
adopting the regulatory text as proposed. Specifically, under Sec.  
257.64(a) new and existing CCR landfills, new and existing CCR surface 
impoundments and all lateral expansions are prohibited from sites 
classified as unstable areas unless the owner or operator makes a 
demonstration, certified by a qualified professional engineer, that 
engineering measures have been incorporated into the CCR unit's design 
to ensure that the structural components will not be disrupted. EPA 
considers a structural component to include any component used in the 
construction and operation of CCR landfill or CCR surface impoundment 
that is necessary to ensure the integrity of the unit and to ensure 
that the contents will not be released to the environment, including 
liners, leachate collection system, embankments, spillways, outlets, 
final covers, inflow design flood controls systems. Liners and leachate 
collection systems require a firm, secure foundation to maintain their 
integrity, and may be disrupted as a result of uneven settlement 
induced by hydrocompaction. Similarly, sudden differential movement 
resulting from CCR placement and the consequent exceedance of the 
weight-bearing strength of subsurface materials in unstable areas can 
destroy liners and damage the unit's structural integrity, resulting in 
catastrophic release of CCR. It is essential for the owner or operator 
of any CCR unit to extensively evaluate the adequacy of the subsurface 
foundation support for the structural components of the unit. 
Therefore, the Agency is making this demonstration mandatory for all 
CCR units; existing CCR units for which a demonstration cannot be made 
must be closed.
    EPA has adopted the following definitions without material change 
from the proposal: Unstable area means a location that is susceptible 
to natural or human-induced events or forces capable of impairing the 
integrity of some or all of the structural components responsible for 
preventing releases from a CCR unit. Natural unstable areas include 
those areas that have poor soils for foundations, areas susceptible to 
mass movements, and karst terrains. Structural components mean liners, 
leachate collection systems, final covers, run-on/run-off systems, and 
any other component used in the construction and operation of a CCR 
unit. Poor foundation conditions means those areas where features exist 
which may result in inadequate foundation support for the structural 
components of a CCR unit. Areas susceptible to mass movement means 
those areas of influence (i.e., areas characterized as having an active 
or substantial possibility of mass movement) where the movement of 
earth material at, beneath, or adjacent to the CCR unit, because of 
natural or man-induced events, results in the downslope transport of 
soil and rock material by means of gravitational influence. Areas of 
mass movement include, but are not limited to, landslides, avalanches, 
debris slides and flows, solifluction, block sliding, and rock fall. 
Karst terrain means an area where karst topography, with its 
characteristic erosional surface and subterranean features, is 
developed as the result of dissolution of limestone, dolomite, or other 
soluble rock. Characteristic physiographic features present in karst 
terrains include, but are not limited to, dolines (sinkholes), vertical 
shafts, sinking streams, caves, seeps, large springs, and blind 
valleys.
    The owner or operator must consider at a minimum, 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 (both surface and 
subsurface). To evaluate subsurface conditions for purposes of Sec.  
257.64(c)(3), EPA considers it essential that the owner or operator 
conduct a geotechnical site investigation, certified by a qualified 
professional engineer, to identify any potential thick layers of soil 
that are soft and compressible (e.g., loess, unconsolidated clays, 
wetland soils), which could cause a significant amount of post-
construction differential settlement of foundation soils, adjacent 
embankments, and slopes unless improved. In addition, it is essential 
that the investigation identify on-site or local soil conditions that 
are conducive to downslope movement of soil, rock, and/or debris (alone 
or mixed with water) under the influence of gravity. Local topography, 
surface and subsurface soils, surface slope angles, surface drainage 
and run-off patterns, seepage patterns, rock mass orientations, joint 
patterns, fissures, and any other landscape factors that could 
influence downslope movement should be identified. Anthropogenic 
activities that could induce instability include mining, cut and fill 
activities during construction, excessive drawdown of groundwater, 
which may cause excessive settlement or bearing capacity failure of 
foundation soils, and use of an old landfill as the foundation for a 
new landfill without verification of complete settlement of the 
underlying wastes.
    In designing a new CCR unit located in an unstable area, recognized 
and generally accepted good engineering practices dictate that a 
stability assessment should be conducted to prevent a destabilizing 
event from damaging the structural integrity of the component systems. 
For CCR units this involves three components: (1) An evaluation of 
subsurface conditions, (2) an analysis of slope stability, and (3) an 
examination of related design needs. In addition to explaining site 
constraints, identifying any soft soils, and recommending any 
appropriate ground improvement techniques, the assessment report should 
include a description of: The site, site geology; and investigative 
methodology; the results from all site investigations including 
subsurface exploration, field and laboratory tests, and test results; 
the subsurface profile, recommended foundation types, depths, and 
bearing capacities; the water content, grain-size distribution, shear 
strength, plasticity, and liquefaction potential of foundation soils 
and subsoils; and other foundation consolidation and settlement issues 
relevant to site development.
    In addition to assessing the ability of soils and rocks to serve as 
a foundation, it is essential that the report also include a stability 
assessment of excavated sideslopes, aboveground embankments or dikes, 
and retaining structures. The slope stability analyses are performed as 
part of an evaluation of the design configuration under all potential 
hydraulic and loading conditions, including conditions that may exist 
during construction of a lateral or vertical expansion. As part of any 
demonstration, owners and operators should make an assessment, 
certified by a qualified professional engineer, that finalized site 
embankments and slopes are able to maintain a stable condition. In 
addition to evaluating the potential for post-construction differential 
settlement, the stability assessment should also consider seepage-
induced saturation and softening of soils, particularly at CCR surface 
impoundments and CCR landfill sites that manage effluent.
    Engineering considerations for CCR landfills and lateral expansions 
located in unstable areas are expected to be

[[Page 21368]]

similar to those for MSWLFs, which can be found in EPA's 1993 Technical 
Manual on Solid Waste Disposal Facility Criteria (EPA530-R-93-017). For 
surface impoundments the relevant design criteria are found in the 
Agency's 1991 Technical Resource Document on Design, Construction and 
Operation of Hazardous and Non-Hazardous Waste Surface Impoundments 
(EPA/530/SW-91/054). Any stability assessment should consider the 
following: (1) The adequacy of the subsurface exploration program; (2) 
the liquefaction potential of the embankment, slopes and foundation 
soils; (3) the expected behavior of the embankment slopes, and 
foundation soils when they are subjected to seismic activity; (4) the 
potential for seepage-induced failure; and (5) the potential for 
differential settlement.
    For facilities in areas of karst, to support the demonstration 
required under the regulations, the owner or operator would need to 
evaluate the subsurface conditions to ensure that the unit is located 
away from the influence of potential sinkholes. For areas where the 
solution-weathered limestone is close to the surface (e.g., Florida) 
recognized and generally accepted good engineering practices dictate 
that there must be no conduits beneath the CCR unit that allow piping 
of groundwater into the karst aquifer, or shallow caves that could 
cause sudden collapse of the unit foundation. Where unconsolidated 
sediments cover underlying limestone, piping is commonly marked by 
paleosinks where sands and clays from the overburden have filled 
solution cavities in the underlying limestone.\60\ Local hydraulic 
gradients in paleosinks typically point downward. EPA generally expects 
the potential for sinkhole development to be minimal at locations in 
karst areas where there are no paleosinks, or historical record of 
sinkhole development, and where there are no local hydraulic gradients 
that point downward.
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    \60\ For examples, see Garlanger, J.E., Foundation Design in 
Florida Karst. Online presentation by Ardaman & Associates. http://www.ardaman.com/foundation_design.htm.
---------------------------------------------------------------------------

    In making a demonstration, it is important for owners and operators 
of CCR landfills and surface impoundments in karst areas to adequately 
characterize subsurface conditions. Karst hydrogeology is complex, 
since contaminant flows can occur along paths and networks that are 
discreet and tortuous, and groundwater monitoring wells must be capable 
of detecting any contaminants released from the CCR unit into the karst 
aquifer. Therefore, the owner or operator will need to ensure, with 
verification by a qualified professional engineer, that monitoring 
wells installed in accordance with Sec.  257.91 will intercept these 
pathways. Verification will usually necessitate the use of tracers to 
track groundwater flow towards offsite seeps or springs from the 
uppermost aquifer beneath the facility.
    Any engineered solution employed to mitigate weak ground strength 
in karst areas must be able to prevent the kind of foundation collapse 
and settlement that could lead to sudden release to the environment of 
CCR with its toxic constituents and associated leachate. Solution 
cavities present at the site should be filled with grout or other 
suitable stiff material to avoid further crumbling and erosion. Where 
necessary, CCR unit foundations could be reinforced with engineered 
ground supports such as concrete footings that bridge voids. Larger 
caverns could be filled with concrete to underpin the CCR unit 
foundation by transferring load to the cavern floor. However, such 
engineered solutions are complex and costly, and the best protection is 
not to site CCR landfills and surface impoundments in karst areas. 
Nevertheless, this rule does not ban the location of CCR landfills, 
surface impoundments, or lateral extensions in karst areas.
7. Closure of Existing CCR Landfills and Existing CCR Surface 
Impoundments
    The final provisions of Sec.  257.60 require owners or operators of 
an existing CCR surface impoundment to demonstrate that the unit meets 
the minimum requirements for placement above the uppermost aquifer 
(i.e., constructed with a base located no less than 1.52 meters (five 
feet) above the upper limit of the uppermost aquifer) no later than 42 
months after the date of publication of this rule in the Federal 
Register.
    Owners and operators of existing CCR surface impoundments subject 
to Sec. Sec.  257.61-257.64 of this rule and existing CCR landfills 
subject to Sec.  257.64, must complete demonstrations by the date 
corresponding to 42 months from publication of this rule. The Agency is 
setting the compliance deadline at 42 months to allow owners and 
operators time to complete the requisite studies (e.g., to adequately 
characterize seasonal variations in the elevation of the top of the 
uppermost aquifer) and to complete any engineering measures necessary 
to allow the CCR unit to meet the performance standards. If closure is 
warranted, it must be initiated no later than 48 months from 
publication of this rule. Closure and post-closure care must be done in 
accordance with Sec. Sec.  257.100-103; which allow certain regulatory 
flexibilities provided specific conditions are met.

D. Design Criteria--Liner Design

    EPA proposed that existing CCR landfills without a composite liner 
could continue to operate and receive CCR without violating the open 
dumping prohibition. Conversely, EPA proposed that existing CCR surface 
impoundments would be required to retrofit with a composite liner 
system, as defined in the proposed rule, within five years of the 
effective date of the rule or to close. EPA also proposed that all new 
CCR units must be constructed with a composite liner and leachate 
collection and removal system.
    In the proposal, EPA defined a composite liner to mean a liner 
system consisting of two components; the upper component consisting of 
a minimum 30-mil flexible membrane liner (FML), and the lower component 
consisting of at least a two-foot layer of compacted soil with a 
hydraulic conductivity of no more than 1 x 10-7 cm/sec.\61\ 
FML components consisting of high density polyethylene (HDPE) were 
required to be at least 60-mil thick; and the FML component was 
required to be installed in direct and uniform contact with the 
compacted soil component.
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    \61\ The definition of hydraulic conductivity is being 
promulgated as proposed, and will mean the rate at which water can 
move through a permeable medium (i.e., the coefficient of 
permeability).
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    EPA solicited comment on a number of issues, including: (1) Whether 
EPA should allow facilities to use an alternative design for new CCR 
units; (2) whether clay liners designed to meet a 1 x 10-7 
cm/sec hydraulic conductivity might perform differently in practice 
than modeled in the risk assessment, including a request for specific 
data on the hydraulic conductivity of clay liners associated with CCR 
units; and (3) whether the effectiveness of such additives as 
organosilanes, would allow the use of these additives in lieu of 
composite liners. (See 75 FR 35203 and 35222.) \62\ With respect to the 
last two issues, the Agency received little comment. However, in 
response to the use of alternative liner designs in lieu of a composite 
liner (as defined in the rule), significant comment was received. 
Commenters advocated for a number of alternative composite liner 
designs, with a majority recommending that a

[[Page 21369]]

geosynthetic clay liner (GCL) be allowed as an alternative to the lower 
component of the composite liner. Other commenters stated that GCLs 
alone should be allowed as an alternative to the proposed composite 
liner. Still others argued that alternative liner designs, such as an 
FML/FML \63\ provided a level of performance similar to the proposed 
composite liner system and should be allowed. Conversely, there were 
also comments opposing the use of any alternative liners, claiming that 
alternatives have not been proven to be effective.
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    \62\ The terms compacted soil and compacted clay are used 
interchangeably, i.e., when referring to a compacted soil liner this 
is the same as referring to a compacted clay liner (CCL).
    \63\ Current terminology favors the use of geomembrane liner or 
GM when referring to flexible membrane liners or FMLs. Hereafter in 
the preamble, except when referring to specific comments or the 
proposed rule, and in the final rule, the Agency will use the term 
geomembrane liner or GM in place of flexible membrane liner or FML.
---------------------------------------------------------------------------

    EPA also received significant comment on the actual design of the 
composite liner system proposed by the Agency as it pertained to CCR 
surface impoundments (see 75 FR 35202-35203).\64\ Commenters argued 
that the proposed requirement for a leachate collection and removal 
system in a CCR surface impoundment was illogical since it would have 
to be constructed between the lower component (two feet of compacted 
soil) and upper component (flexible membrane liner) and the proposed 
rule specifically states that the flexible membrane liner component 
must be installed in direct and uniform contact with the compacted soil 
component. Commenters reasoned that the inclusion of a leachate 
collection and removal system between the upper and lower components 
precluded direct and uniform contact between the two components and 
that placing a leachate collection and removal system between the lower 
and upper components of a composite liner would compromise the 
integrity of the composite liner. With regard to this last point, the 
Agency has reviewed the requirements for a proposed composite liner 
system as it would pertain to CCR surface impoundments and agrees that 
the leachate collection and removal system requirements proposed for 
CCR surface impoundments would be counterproductive; EPA proposed this 
requirement in error. The integrity of the composite liner system is 
indeed dependent upon the direct and uniform contact of the upper GM 
component with the lower soil component. The proposed requirement for 
CCR surface impoundments to construct a leachate collection system 
between the FML and soil components would prevent the direct and 
uniform contact of the upper and lower components and, therefore, 
compromise the integrity of the composite liner. For this reason, EPA 
is not requiring a leachate collection and removal system for new 
surface impoundments or any lateral expansion of a CCR surface 
impoundment.
---------------------------------------------------------------------------

    \64\ See proposed Sec.  257.71 which states that an existing CCR 
surface impoundment shall be constructed with a composite liner and 
a leachate collection system between the upper and lower components 
of the composite liner; where a composite liner means a system 
consisting of two components; the 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 1 x 10-7 cm/sec. 
The FML component would be required to be installed in direct and 
uniform contact with the compacted soil component (see 75 FR 35243).
---------------------------------------------------------------------------

    While EPA agrees with those commenters arguing that new CCR units 
should only be installed with a composite liner system of some kind, 
the Agency has concluded that not all alternative designs for a 
composite liner system should necessarily be rejected as insufficiently 
protective. Many commenters provided strong and compelling evidence 
that the specific composite liner system described in the proposed rule 
was not always feasible or necessary to protect groundwater resources 
and that alternate composite liner designs could be equally protective, 
and may be a necessity in many areas of the country where soil with the 
appropriate hydraulic conductivity may not be available (e.g., 
Alaska).\65\
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    \65\ See for example comments from the states of Alaska (EPA-HQ-
RCRA-2009-0640-06409); Florida (EPA-HQ-RCRA-2009-0640-06846); and 
North Carolina (EPA-HQ-RCRA-2009-0640-09282) available at 
www.regulations.gov.
---------------------------------------------------------------------------

    In re-evaluating the proposed requirement for a composite liner 
system, EPA was influenced by a number of factors.\66\ First, the data 
provided by commenters showing the performance of a GM/GCL design. 
Second, EPA's own studies showing that a GM/GCL liner can be 
constructed to achieve hydraulic efficiencies in the range of 99 to 
99.9% which meets or exceeds the hydraulic performance of a GM/
compacted clay liner (CCL) design.\67\ In addition, these high 
efficiencies demonstrate that the GCL component of a GM/GCL composite 
liner is at least as effective in impeding leakage through holes in the 
GM component of the composite liner system as a CCL with a hydraulic 
conductivity no more than 1 x 10-7 cm/sec.\68\ In fact, EPA 
has developed guidance for the selection and installation of various 
types of liners including a GM/GCL.\69\ And third, EPA was influenced 
by the many comments arguing that a ``one-size-fits all'' approach to 
liner design stifles design innovation and regulatory flexibility in 
addressing site specific factors such as geologic or climatic 
conditions. These commenters reasoned that if EPA established some type 
of performance standard for composite liners, it would mitigate the 
negative impacts of a ``one-size fits all'' regulatory framework.
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    \66\ Geomembranes (GMs), which are flexible membrane liners 
(FMLs), are thin materials manufactured from polymers and reinforced 
with woven fabric or fibers which are used as hydraulic barriers. 
Resins used to manufacture geomembrane liners typically include high 
density polyethylene (HDPE), linear low density polyethylene 
(LLDPE), low density linear polyethlene (LDLPE), very low density 
polyethylene (VLDPE) and polyvinyl chloride (PVC). Geomembranes 
manufactured using HDPE are the least flexible of the geomembranes.
    \67\ USEPA, ``Assessment and Recommendations for Improving the 
Performance of Waste Containment Systems,'' EPA 600/R-02/029, 
December 2002. http://nepis.epa.gov/Adobe/PDF/P1001O83.pdf.
    \68\ USEPA, ``Assessment and Recommendations for Improving the 
Performance of Waste Containment Systems,'' EPA 600/R-02/029, 
December 2002.
    \69\ USEPA, ``Guide for Industrial Waste Management,'' Chapter 7 
(http://www.epa.gov/osw/nonhaz/industrial/guide/pdf/chap7b.pdf).
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1. Development of Composite Liner Design Criteria
    In this final rule EPA is requiring all new CCR units to be 
designed and constructed with a composite liner as specified in Sec.  
257.70. EPA is also providing the owner or operator with an option to 
install an alternative composite liner provided it meets the required 
performance standard and it is certified by a qualified professional 
engineer. EPA has concluded, consistent with many of the comments 
received and its own analysis, that an alternative composite liner for 
new CCR units is warranted if it can be shown to be equivalent to the 
performance of a composite liner and affords the same protections to 
groundwater resources as a composite liner. The Agency is promulgating 
this alternative option to provide flexibility in designing and 
constructing a protective composite liner system that addresses site 
specific conditions and situations. The Agency acknowledges that it was 
overly prescriptive by requiring one particular type of liner rather 
than relying on a performance standard to define the lower component of 
the composite liner. The overwhelming amount of data supporting the 
effectiveness of a GC/GCL liner has convinced the Agency that the final 
rule should allow for some flexibility in composite liner designs. As 
such, the Agency is allowing new CCR units to be designed and 
constructed

[[Page 21370]]

with an alternative composite liner, as described below, provided the 
lower component of the composite liner meets a specified performance 
standard that ensures it functions in a manner equivalent to the 
composite liner system defined in the rule.
    Composite liner systems installed in either a CCR landfill or CCR 
surface impoundment provide an effective hydraulic barrier by combining 
the complementary properties of the two different liner components. The 
geomembrane provides a highly impermeable layer that can maximize 
leachate collection and removal in a CCR landfill or minimize 
infiltration of leachate in a CCR surface impoundment, while the soil 
component (e.g., CCL) serves as a backup in the event of any leakage/
infiltration from the geomembrane occurs. Data indicate that 
alternatives to the lower component of the composite liner system 
(e.g., GCLs) are available and can perform at a level equivalent to a 
compacted soil liner, based on a comparison of their flow rates with 
two feet of compacted soil with a hydraulic conductivity of no more 
than 1 x 10-7 cm/sec.
2. Liner Designs That Would Not Meet the Requirements of a Composite 
Liner or Alternative Liner
    Contrary to the arguments made by several commenters, EPA has 
concluded that a composite liner consisting of two 30-mil GMs (GM/GM) 
will not provide an equivalent degree of protection as a composite 
liner consisting of a GM and two feet of compacted soil, or an 
alternative composite liner such as a GM/GCL. While GMs have the 
advantages of extremely low rates of water permeation, the 
disadvantages of a composite liner consisting of two GMs include 
leakage through occasional GM imperfections and punctures, potential 
for slippage along the interface between the GMs, and GM embrittlement 
over time. Furthermore, a critical component of a composite liner is 
the compacted soil or GCL component beneath the GM layer that will 
impede the flow of liquid that may leak through a hole or defect in the 
GM. This added protection cannot be achieved using two GMs for the 
composite liner. Additionally, the potential exists for liquid 
transport through the GMs through holes caused by punctures, tears, 
flawed seams, etc. If a puncture occurs, the puncture could compromise 
both GMs and create a conduit for liquid flow to underlying permeable 
soil. Moreover, a liner system consisting of two GMs in contact with 
each other poses the risk of creating a slip plane that may compromise 
the stability of the disposal unit (although EPA acknowledges that 
using textured GMs would reduce or eliminate this particular risk). 
These data are documented in EPA research.\70\
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    \70\ ``Assessment and Recommendations for Improving the 
Performance of Waste Containment Systems.''
---------------------------------------------------------------------------

    Consistent with the previous determination, EPA has also determined 
that the double liner system set forth in Florida regulations (see 
Florida Rules 62-701.400(3)(c), F.A.C) also does not meet the level of 
performance achieved by EPA's composite liner system or the alternative 
liner system. While this double liner system provides the advantage of 
a leak detection system between the two GMLs, the lower composite 
liner, consisting of a 60-mil HDPE over six inches of soil with a 
saturated hydraulic conductivity of less than or equal to 1 x 
10-5 cm/sec, is not equivalent to a GM over two feet of 
compacted soil with a hydraulic conductivity of less than or equal to 1 
x 10-7 cm/sec. To be hydraulically equivalent, soil with a 
hydraulic conductivity of 1 x 10-5 cm/sec would need to be 
on the order of 100 times thicker than soil with a hydraulic 
conductivity of less than or equal to 1 x 10-7 cm/sec. 
Similarly, a lower composite liner consisting of a 60-mil HDPE over a 
GCL with a hydraulic conductivity not greater than 1 x 10-7 
cm/sec would require a GCL thickness of 24 inches to be equivalent to a 
GM over two feet of compacted soil with a hydraulic conductivity of 
less than or equal to 1 x 10-7 cm/sec.
    EPA has also examined the performance of GCLs approved for use as 
alternatives to composite liners in MSWLFs.\71\ The EPA report titled 
``Assessment and Recommendations for Improving the Performance of Waste 
Containment Systems,'' \72\ concluded that if a CCL or GCL is used 
alone, liquid migration can occur over the entire area of the liner 
that is subject to a hydraulic head. The report also concluded that in 
a composite liner, leakage will only occur at the location of the 
geomembrane penetration (e.g., hole, tear), and will be much slower 
than flow through an orifice due to the hydraulic impedance provided by 
the CCL or GCL alone. The report also evaluated, among other 
characteristics, the hydraulic efficiencies of a GM/GCL composite liner 
system for 28 cells at seven landfills. Liner hydraulic efficiencies 
were reported between 97% and 100%. However, potential stability 
problems were reported with GCLs constructed on slopes greater than 10 
H:1 V (5.7[deg]), and GCLs may not be appropriate for the disposal of 
liquid wastes or sludges. The Agency is also concerned that GCLs, being 
much thinner than the two feet of compacted soil required for composite 
liners, may allow for the flow of liquids through the GCL at a faster 
rate than through two feet of compacted soil. Taking all of this 
information into account, the Agency remains unconvinced that a GCL 
alone is a viable alternative to a composite liner.
---------------------------------------------------------------------------

    \71\ ``Geosynthetic Clay Liners Used in Municipal Solid Waste 
Landfills,'' http://www.epa.gov/wastes/nonhaz/municipal/landfill/geosyn.pdf; ``Geosynthetic Clay Liners in Waste Containment,'' 
http://www.epa.gov/superfund/remedytech/tsp/download/2001_meet/prez/carson.pdf; and ``Assessment and Recommendations for Improving the 
Performance of Waste Containment Systems,'' http://nepis.epa.gov/Adobe/PDF/P1001O83.pdf.
    \72\ ``Assessment and Recommendations for Improving the 
Performance of Waste Containment Systems.''
---------------------------------------------------------------------------

3. Design Requirements
a. Existing CCR Landfills
    As proposed, the final rule allows existing CCR landfills as 
defined in Sec.  257.54, to continue to operate without retrofitting 
with a composite liner and leachate collection and removal system. As 
previously discussed, given the volume of the material currently 
managed in CCR landfills, the potential for disruption in CCR disposal 
capacity if existing CCR landfills were required to retrofit would be 
significant. Significant disruptions in the state-wide solid waste 
management (and possibly power generation) are associated with 
significant risks to public health and the environment in their own 
right. EPA has concluded that these risks are greater than the risks 
associated with allowing unlined CCR landfills to continue to operate. 
Further, existing CCR landfills will be required to comply with the 
extensive groundwater monitoring and corrective action requirements, 
among others, to ensure that any groundwater releases from the CCR unit 
are identified and promptly remediated, which will significantly 
mitigate the risks from these existing units. By themselves, the risk 
assessment results and the risk migration from the other regulatory 
requirements in this rule would not support a decision to allow these 
CCR units to continue to operate on a national basis. But when the 
risks associated with the level of disruption EPA estimates to be 
possible from requiring existing CCR landfills to retrofit are also 
included, the totality of the evidence supports a determination that 
allowing these units to continue operating meets the section 4004(a) 
standard.

[[Page 21371]]

b. Existing CCR Surface Impoundments
    In a departure from the proposed rule and after considerable 
evaluation and analysis, the Agency is finalizing a provision to allow 
all existing CCR surface impoundments to remain in operation provided 
certain conditions are met.\73\ Owners or operators of existing CCR 
surface impoundments are required, within one year of the effective 
date of the rule, to document, certified by a qualified professional 
engineer, whether the unit is constructed with any one of the three 
liner types: (1) A liner consisting of a minimum of two feet of 
compacted soil with a hydraulic conductivity of no more than 1 x 
10-7 cm/sec; (2) a composite liner that meets the 
requirements of Sec.  257.70(b); or (3) an alternative liner that meets 
the requirements of Sec.  257.70(c). In some instances, owners or 
operators may have information readily available to determine if an 
existing CCR surface impoundment is constructed with one of the three 
liner types listed above. On the other hand, this information may not 
be readily available and may require an owner or operator to conduct an 
engineering evaluation to determine if the unit was constructed with 
any of the three liner type. Factors such as the availability of 
engineering personnel and weather may impede the engineering 
evaluation. Therefore, EPA believes that 12 months from the effective 
date, or 18 months from publication of the rule, is a reasonable amount 
of time to make the determination of whether the existing CCR surface 
impoundment was constructed with one of the three liner types described 
above. Existing surface impoundments with liners that meet the criteria 
established for any of the three specified liner types are considered 
to be an ``existing lined CCR surface impoundments.'' These existing 
lined surface impoundments can continue to operate until the owner or 
operator decides to initiate closure, provided the unit does not meet 
other requirements of the rule that independently mandate closure of 
the unit (e.g., location criteria (Sec. Sec.  257.60-257.64) or 
structural integrity factors of safety (Sec.  257.73)). Existing 
unlined CCR surface impoundments must also cease receiving CCR and 
initiate closure if an owner or operator determines, at any point in 
time, as part of its groundwater monitoring program that the 
concentrations of one or more constituents listed in appendix IV to 
part 257 are detected at a statistically significant level above the 
groundwater protection standard established for that unit. EPA agrees 
with the many commenters who argued that existing unlined CCR surface 
impoundments should not be required to close prematurely if they are 
operating as designed and are complying with all of the requirements of 
the rule, including all groundwater protection standards. Taking into 
account the additional protections required under this rule (e.g., 
location restrictions, groundwater monitoring, corrective action, 
structural integrity criteria, inspections and fugitive dust controls), 
the Agency has concluded that the risks posed by unlined CCR surface 
impoundments that are not ``leaking'' (i.e., exceeding any groundwater 
protection standard) are not sufficient to warrant requiring these 
units to close. However, once a groundwater protection standard is 
exceeded (i.e., the unit is leaking), without any type of liner system 
in place, leachate will flow through the unit and into the environment 
unrestrained and the only corrective action strategy that EPA can 
determine will be effective at all sites nation-wide requires as its 
foundation the closure of the unit.
---------------------------------------------------------------------------

    \73\ Existing CCR surface impoundments will not be required, as 
was proposed, to retrofit to a composite liner or close within five 
years of the effective date of the rule (see 57 FR 35202).
---------------------------------------------------------------------------

    EPA acknowledges that it may be possible at certain sites to 
engineer an alternative to closure of the unit that would adequately 
control the source of the contamination and would otherwise protect 
human health and the environment. However, the efficacy of those 
engineering solutions will necessarily be determined by individual site 
conditions. As previously discussed, the regulatory structure under 
which this rule is issued effectively limits the Agency's ability to 
develop the type of requirements that can be individually tailored to 
accommodate particular site conditions. Under sections 1008(a) and 
4004(a), EPA must establish national criteria that will operate 
effectively in the absence of any guaranteed regulatory oversight 
(i.e., a permitting program), to achieve the statutory standard of ``no 
reasonable probability of adverse effects on health or the 
environment'' at all sites subject to the standards. EPA was unable to 
develop a performance standard that would allow for alternatives to 
closure, but would also be sufficiently objective and precise to 
minimize the potential for abuse. There are too many factors that 
determine whether a particular engineering solution will meet the 
section 4004(a) standard at a particular site. And the risks of these 
units are simply too high.
    Conversely, existing lined surface impoundments that exceed their 
groundwater protection standard are in a better position to manage the 
leak because it is usually caused by some localized or specific defect 
in the liner system that can more readily be identified and corrected. 
Consequently, this rule is not requiring existing lined CCR surface 
impoundment to close if an exceedance of a groundwater protection 
standard is detected; rather the Agency is affording the owner or 
operator with the opportunity to rely on corrective action measures to 
bring the risks back to acceptable levels (i.e., control the source of 
the release and remediate the contamination), without mandating closure 
of the unit.
c. New CCR Landfills and New CCR Surface Impoundments and All Lateral 
Expansions
    Both the CCR damage case history and the risk assessment clearly 
show the need for and the effectiveness of appropriate liners in 
reducing the potential for groundwater contamination at CCR landfills 
and CCR surface impoundments. Accordingly, EPA is finalizing liner and 
leachate collection and removal system requirements for new CCR 
landfills and all lateral expansions of these units. Similarly, EPA is 
finalizing liner requirements for new CCR surface impoundments and all 
lateral expansions of these units.
    Specifically, EPA is requiring new CCR landfills, new CCR surface 
impoundments, and all lateral expansions be constructed with a 
composite liner (see Sec.  257.70). The composite liner must consist of 
two components; an upper component consisting of a minimum 30-mil 
geomembrane liner (GM), and a lower component consisting of at least a 
two-foot layer of compacted soil with a hydraulic conductivity of no 
more than 1 x 10-7 centimeters per second (cm/sec). GM 
components consisting of high density polyethylene (HDPE) must be at 
least 60-mil thick and the GM or upper liner component must be 
installed in direct and uniform contact with the compacted soil or 
lower liner component
    New CCR landfills or lateral expansions of these units are also 
required to be constructed with a leachate collection and removal 
system designed to maintain less than a 30-centimeter depth of leachate 
over the composite liner. A leachate collection and removal system is 
not required for new CCR surface impoundments

[[Page 21372]]

because, as previously discussed, a leachate collection system 
installed between a single composite liner system is not practicable 
and would compromise the integrity of the composite liner system.
    In addition, in response to comments on the proposed rule, EPA is 
allowing alternatives to the lower component of the composite liner 
system provided the flow rate through the lower component is no greater 
than the flow rate through two feet of compacted soil with a hydraulic 
conductivity of 1 x 10-7 cm/sec. The lower component must 
also be a recognized liner material; e.g., soil, clay, or GCL. 
Alternative composite liners using compacted soil or clay as the lower 
component must be constructed with the upper component in intimate 
contact with the lower component; i.e., the geomembrane must be 
installed to ensure good and uniform contact with the lower component. 
The hydraulic conductivity for the two feet of compacted soil used in 
the flow rate comparison must be no greater than 1 x 10-7 
cm/sec. The hydraulic conductivity of the lower component must be 
determined using recognized and generally accepted engineering methods, 
for example, ASTM D5084-10, ``Standard Test Methods for Measurement of 
Hydraulic Conductivity of Saturated Porous Materials Using a Flexible 
Wall Permeameter,'' ASTM International, West Conshohocken, PA, 2012, 
DOI: 10.1520/D5084-10, www.astm.org for compacted soils or clays, or 
ASTM Standard D6766-12, ``Standard Test Method for Evaluation of 
Hydraulic Properties of Geosynthetic Clay Liners Permeated with 
Potentially Incompatible Aqueous Solutions,'' ASTM International, West 
Conshohocken, PA, 2012, DOI: 10.1520/D6766-12, www.astm.org for GCLs. 
The flow rate comparison for the lower component must be made using 
Darcy's Law for gravity flow through porous media, which is an 
empirical law which states that the velocity of flow through porous 
media is directly proportional to the hydraulic gradient. The use of 
Darcy's Law to calculate fluid flow through porous media is a well-
established and generally accepted engineering methodology, and is the 
foundation for EPA's Composite Model for Leachate Migration with 
Transformation Products (EPACMTP) and is generally recognized to 
evaluate steady state flow of liquids through soils and GCLs.\74\ 
EPACMTP is a subsurface fate and transport model EPA uses to simulate 
the impact of the release of constituents present in waste that is 
managed in land disposal units. Accordingly, the flow rate comparison 
for the lower component of alternative composite liner must be made 
using the following equation which is derived from Darcy's Law.
---------------------------------------------------------------------------

    \74\ See for example EPA's Composite Model for Leachate 
Migration with Transformation Products (EPACMTP) at http://www.epa.gov/epawaste/nonhaz/industrial/tools/cmtp/, ``Assessment and 
Recommendations for Improving the Performance of Waste Containment 
Systems.'' Giroud, J.P., Badu-Tweneboah, K. and Soderman, K.L., 
1997, ``Comparison of Leachate Flow Through Compacted Clay Liners 
and Geosynthetic Clay Liners in Landfill Liner Systems,'' 
Geosynthetics International, Vol. 4, Nos. 3-4, pp. 391-431 (http://www.geosyntheticssociety.org/Resources/Archive/GI/src/V4I34/GI-V4-N3&4-Paper7.pdf), and ``Design Considerations for Geosynthetic Clay 
Liners (GCLs) in Various Applications,'' Geosynthetic Research 
Institute, January 9, 2013 (http://www.geosynthetic-institute.org/grispecs/gcl5.pdf).
[GRAPHIC] [TIFF OMITTED] TR17AP15.003

---------------------------------------------------------------------------
where:

Q = flow rate,
A = surface area of the liner,
q = flow rate per unit area,
k = hydraulic conductivity of the liner,
h = hydraulic head above the liner, and
t = thickness of the liner.

    A qualified professional engineer must certify that the design and 
construction of either the composite liner or the alternative composite 
liner meets the requirements of Sec. Sec.  257.70(b) or (c).
    EPA has also supplemented the composite liner criteria for 
landfills with performance standards that provide more precise 
direction to the professional engineer regarding the ``recognized and 
generally accepted good engineering practices'' that need to be used in 
the design and construction of composite liner systems to ensure that 
the liner system will continue to perform as designed. These criteria, 
which have been codified at Sec. Sec.  257.70(b) and 257.70(c), have 
been adopted in response to comments requesting that EPA provide the 
professional engineers that will be required to certify that CCR units 
meet the requirements of the rule, with more precise and objective 
criteria. These criteria reflect the engineering specifications 
necessary to prevent liner failures resulting from improper design and 
construction and to ensure that the liner will continue to perform 
correctly. These provisions will ensure not only that the liner is 
properly designed and constructed, but also that the system will 
continue to safely perform throughout the landfill's active life and 
through post closure care. The criteria have been adopted from the 
technical provisions proposed under the subtitle C provisions for CCR 
landfills, and are consistent with design requirements set forth for 
hazardous waste landfills regulated under part 265 of RCRA, as well as 
existing guidance and recognized good engineering practices for the 
design and construction of MSWLFs.\75\
---------------------------------------------------------------------------

    \75\ ``Technical Guidance Document: Quality Assurance and 
Quality Control for Waste Containment Systems.'' U.S. Environmental 
Protection Agency. Risk Reduction Engineering Laboratory, Office of 
Research and Development, Cincinnati, OH 45268. EPA/600/R-93/182. 
September 1993.
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    Specifically, the Agency is modifying the composite and alternative 
liner design requirements by requiring the composite or alternative 
liner to be chemically compatible with the CCR and of adequate strength 
and thickness to prevent failure. The liner system must also provide 
appropriate shear strength between the two components to prevent 
sliding of the upper component. In addition, the Agency is requiring 
that liners be placed on an adequate foundation and installed to cover 
all areas that might come into contact with the CCR.
    For new CCR landfills, which are required to have a leachate 
collection and removal system designed and operated to maintain less 
than a 30 centimeter depth of leachate, the Agency is also requiring, 
that the leachate collection and removal system be constructed of 
sufficient strength and thickness to prevent collapse from the pressure 
of the CCR and to minimize clogging during the active life and post 
closure care period.\76\
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    \76\ Hardin, PE, Christopher D, and Perotta, PE Nick L. 
``Operations and Maintenance Guidelines for Coal Ash Landfills--Coal 
Ash Landfill are NOT the Same as Subtitle D Solid Waste Landfills''. 
Presented at the 2011 World of Coal Ash Conference; May 9-12, 2011 
in Denver, Colorado. http://www.flyash.info/2011/127-Hardin-2011.pdf.
---------------------------------------------------------------------------

4. Vertical Expansions of New and Existing CCR Landfills and All 
Lateral Expansions
    In the proposed rule, EPA stated that CCR landfills could 
vertically expand without retrofitting, in order to alleviate concerns 
with regard to CCR disposal capacity in the short term. In the few 
comments to the proposed rule which mentioned vertical expansions of 
landfills, commenters requested that the Agency clarify the design 
standards that vertical expansions would have to meet. Information 
collected to date, which is included in the docket supporting the final 
rule, leads the Agency to conclude there are no issues unique to 
vertical expansions of CCR landfills that warrant modifications to the 
technical standards

[[Page 21373]]

being promulgated in this rule. Therefore, vertical expansions of 
existing CCR landfills are not subject to the provisions governing new 
units, but are subject to all applicable requirements for existing CCR 
landfills. To be clear however, while the location requirements 
relating to the placement above the water table, wetlands, fault areas, 
and seismic impact zones do not apply to existing CCR landfills, all of 
these restrictions apply to lateral expansions of existing CCR units, 
as well as new CCR units. Consequently, under this rule, owners or 
operators of existing CCR landfills can continue to vertically expand 
their existing facilities in these locations, but must comply with the 
provisions governing new units if they wish to laterally expand.
5. Construction of New CCR Landfills or Any Lateral Expansion Over an 
Existing CCR Unit
    On August 2, 2013, EPA published a NODA that among other things, 
solicited comment regarding a particular type of CCR management unit 
described by some commenters in the proposed rule as ``overfills'' (see 
78 FR 46940). Overfills are CCR landfills constructed over a closed CCR 
surface impoundment. As discussed in the NODA, in developing the 
proposed rule, EPA was not aware that CCR was managed in this fashion 
and so did not either evaluate this specific management scenario or 
propose technical requirements specifically tailored to this type of 
unit. Under the proposed rule, these types of units would need to 
comply with both the requirements applicable to the closure of surface 
impoundments or landfills, and with all of the technical requirements 
applicable to new landfills. Information collected since the proposal 
confirmed that the practice of constructing overfills for the disposal 
of CCR is conducted with some regularity, and raised questions as to 
whether overfills would be effectively regulated under the proposed 
technical requirements of the rule. In the NODA, to aid in the 
development of final technical requirements, EPA solicited data and 
information that directly addressed existing engineering guidelines or 
practices applicable to this units, as well as any regulatory 
requirements governing the siting, design, construction, and long-term 
protectiveness of these units for the disposal of CCR.
    The Agency received numerous comments on the NODA. The majority of 
commenters agreed that overfills are commonly employed to allow 
continuing use of CCR disposal sites and to avoid the need to develop 
CCR management units at other sites. Some commenters added that: (1) 
The engineering design of an overfill can increase the stability of the 
underlying surface impoundment or landfill; (2) the use of an overfill 
facility reduces the need for new infrastructure construction; and (3) 
an overfill avoids having to transport CCR significant distances for 
off-site disposal.
    Other commenters mentioned that several states had experience with 
overfills and have applied requirements such as liner systems, 
monitoring wells, and stormwater modeling on a case-by-case basis using 
best engineering practices. They added that overfills pose unique 
construction and operational issues depending on the site and the 
characteristics of the underlying unit, and that the construction of 
these units will therefore vary to account for these conditions. 
Commenters identified several issues requiring additional attention 
during design and construction of overfills including seismic and 
static liquefaction, settlement, foundation improvement, partial 
overfills, groundwater upwelling, groundwater monitoring, and 
wastewater infrastructure.
    Upon review of these comments and further evaluation, the Agency 
has concluded that while there may be technical issues relating to the 
design, construction, and maintenance of overfills, the technical 
standards for CCR landfills are sufficiently flexible that no 
modifications are necessary to accommodate such units. For example, 
while the design and construction of groundwater monitoring systems may 
be technically more challenging, the final standards already allow for 
the construction of a multi-unit system. The performance standards and 
technical specifications laid out in the technical criteria developed 
for this rule are equally as applicable to overfills (and as 
protective) as to other new units. In essence, EPA is retaining the 
approach from the proposal that overfills will need to comply with both 
the requirements applicable to the closure of surface impoundments or 
landfills, and with all of the technical requirements applicable to new 
landfills. Thus, overfills cannot be constructed unless the underlying 
foundation--i.e., the existing CCR surface impoundment has first been 
dewatered, capped, and completely closed. And because overfills are 
considered to be ``new CCR landfills,'' the design and construction of 
such units must comply with the technical requirements that address 
foundation settlement, overall and side slope stability, side slope and 
subgrade reinforcement, and leachate collection and groundwater 
monitoring system requirements, which will all need to be evaluated 
independent of the underlying CCR unit to ensure that the overfill 
design is environmentally protective. This evaluation must also be 
certified by a qualified professional engineer.
    Under the location standards applicable to new CCR units, subgrade 
soils must be capable of providing stable structural support to the new 
liner system. A foundation composed of unconsolidated materials, such 
as CCR that is susceptible to slip-plane failure, is an unstable area 
(man-made) and, under provisions of this rule, is therefore a 
prohibited location for new CCR units. The TVA Kingston ash fill 
failure was at least partly attributable to slip-plane failure of 
saturated CCR that made up the subgrade and foundation beneath the 
unit.
    Similarly, prudent and standard engineering practice for new CCR 
landfills requires that the base and side slopes of the overlying CCR 
landfill be able to maintain the structural integrity of the unit. If 
necessary, the subgrade should be reinforced with a geotextile fabric, 
or otherwise improved, to stabilize existing CCR in the underlying unit 
and to minimize tensile strain in the liner system. Slopes should be 
reinforced to prevent downhill sliding and to protect the leachate 
drainage system.
    EPA is aware from comments that at least one facility is 
consolidating wet CCR in an active CCR surface impoundment through 
placement of dry ash over the wet CCR, and thereby converting the 
impoundment to a dry landfill, without stabilizing the CCR in the unit 
or capping the unit. This practice will no longer be permitted under 
the final rule criteria. Although no modifications were determined to 
be necessary to the individual technical criteria, EPA has added 
specific provisions that clarify the status of overfills, and clearly 
prohibit construction of a CCR landfill over a CCR surface impoundment 
unless the CCR in the underlying unit has first been dewatered and the 
unit is capped and completely closed. Dewatering, capping and closure 
of the underlying CCR unit prior to construction of the overlying CCR 
landfill renders the CCR overfill less susceptible to slip-plane 
failure. Conversion of an impoundment to a landfill without these 
measures involves a complex construction process that is highly site 
specific; EPA was unable to develop sufficiently objective performance 
standards that could be

[[Page 21374]]

independently verified outside of a supervised permit program. Because 
this rule is self-implementing EPA is, therefore, prohibiting 
construction of new CCR landfills over operational CCR surface 
impoundments to prevent the creation of structurally unstable units 
that could lead to catastrophic failures.

E. Design Criteria--Structural Integrity

    Under the design criteria requirements, EPA proposed to establish 
structural stability standards for existing and new CCR surface 
impoundments and lateral expansions of these units based on a 
combination of existing federal programs and requirements applicable to 
dam safety. The proposed rule was largely based on the requirements 
promulgated for coal slurry impoundments regulated by the MSHA at 30 
CFR 77.216. (See 75 FR 35176.) EPA also developed aspects of the 
proposal based on the USACE and FEMA's dam safety programs. Consistent 
with the MSHA requirements, EPA proposed that existing and new CCR 
surface impoundments that could impound CCR to an elevation of five 
feet or more above the upstream toe of the structure and have a storage 
volume of 20 acre feet or more, or that impound CCR to an elevation of 
20 feet or more above the upstream toe of the structure would be 
required to provide detailed information on the history of construction 
of the existing CCR surface impoundment and to meet certain performance 
standards. Specifically, facilities would need to (1) develop plans for 
the design, construction, and maintenance of existing impoundments, (2) 
conduct periodic inspections by trained personnel knowledgeable in 
impoundment design and safety, and (3) provide an annual certification 
by an independent registered professional engineer that all 
construction, operation, and maintenance of impoundments is in 
accordance with the approved plan.
    EPA also proposed to require the facility to obtain certification 
from a professional engineer that the ``design of the CCR surface 
impoundment is in accordance with current, prudent engineering 
practices for the maximum volume of CCR slurry and CCR wastewater which 
can be impounded therein and for the passage of run-off from the design 
storm which exceeds the capacity of the CCR surface impoundment. To 
support this performance standard, EPA proposed to require the facility 
to conduct specific analyses, and to provide information on critical 
structures. This includes the proposed requirements to compute the 
minimum factor of safety for slope stability of the retaining 
structures of the unit, including the methods and calculations used to 
determine each factor of safety, and to provide information on the 
physical and engineering properties of the foundations of the CCR 
surface impoundment, any foundation improvements, drainage provisions, 
spillways, diversion ditches, outlet instrument locations and slope 
protections, and area capacity curves. EPA proposed to require more 
extensive information from new CCR surface impoundments addressing the 
design, construction, and maintenance of the new CCR unit, recognizing 
that such information may not be available for existing units.\77\ In 
addition, EPA proposed to require existing and new CCR surface 
impoundments of a specified size to calculate and report the hazard 
potential classification of the unit. Finally, EPA proposed that any 
CCR surface impoundments classified as having a high or significant 
hazard potential, as certified by an independent registered 
professional engineer, be required to develop and maintain an Emergency 
Action Plan defining the responsible persons and actions to be taken in 
the event of a dam safety emergency.
---------------------------------------------------------------------------

    \77\ In the proposed rule under proposed Sec.  257.71--Design 
criteria for existing CCR surface impoundments, the Agency only 
required the hazard potential classification for which the facility 
is designed and a detailed explanation of the basis for the 
classification (Sec.  257.71(d)(1)) ``as may be available'' (Sec.  
257.71(d)). Similarly the computed minimum factor of safety for 
slope stability of the CCR retaining structure(s) and the analyses 
used in the determination (Sec.  257.71(d)(11) ``as may be 
available'' (Sec.  257.71(d)).
---------------------------------------------------------------------------

    The Agency solicited comment on a number of issues relating to the 
proposed structural stability requirements. In particular, the Agency 
solicited comment on the scope of these requirements and whether they 
should apply to all CCR surface impoundments regardless of height and/
or storage volume or whether EPA should adopt, as proposed and 
consistent with the MSHA requirements, the size cut-off described in 
the proposed rule; i.e., impounding CCR to an elevation of five feet or 
more above the upstream toe of the structure and have a storage volume 
of 20 acre feet or more, or impounding CCR to an elevation of 20 feet 
or more above the upstream toe of the structure.
    EPA also solicited comment on several alternative strategies for 
regulating the structural stability of CCR surface impoundments in lieu 
of regulation under RCRA subtitle D. The first alternative involved 
using NPDES permits rather than RCRA regulations to address dam safety 
and structural integrity. The second strategy would eliminate the 
structural integrity requirements from the RCRA subtitle D rule and, 
instead, have EPA establish and fund a program for conducting annual 
(or at some other frequency) structural stability assessments of CCR 
surface impoundments having a ``high'' or ``significant'' hazard 
potential rating as defined by criteria developed by the USACE for the 
NID. EPA would conduct these assessments and, using appropriate 
authorities already available under RCRA, CERCLA, and/or the Clean 
Water Act, would require facilities to respond to issues identified 
with their CCR surface impoundments. The rationale behind this 
suggested approach was that annual inspections would be far more cost 
effective than the phase-out of CCR surface impoundments--approximately 
$3.4 million annually for annual assessments, as compared to the $876 
million annual cost of a rule that also phased out CCR. EPA also 
solicited comments on the effectiveness of this approach in ensuring 
the structural integrity of CCR surface impoundments. (See for example: 
75 FR at 35176, 35223.)
    On October 21, 2010, EPA published a NODA announcing that EPA 
intended to consider the information that had been developed through 
the Agency's Assessment Program as part of the CCR rulemaking. The NODA 
described the Assessment Program, and solicited comment on ``the extent 
to which both the CCR surface impoundment information collection 
request responses and assessment materials on the structural integrity 
of these impoundments should be factored into EPA's final rule on the 
Disposal of Coal Combustion Residuals from Electric Utilities.'' (See 
75 FR 35128.) This included the responses to information requests that 
EPA originally sent to electric utilities, as well as reports and 
materials related to the site assessments developed through the 
Assessment Program. At that time, EPA had completed the assessments and 
the final reports for 53 units. On August 2, 2013, EPA published 
another NODA soliciting public comment on the additional assessments 
that had been completed since the 2010 NODA. In all, this included 
draft and final reports for a total of 522 units and 209 facilities. 
EPA again solicited comment on the extent to which this information 
should be taken into account as part of this rulemaking.
    EPA received numerous comments on the proposed structural stability 
requirements. Many of these fell within two general areas: (1) EPA's 
approach of

[[Page 21375]]

establishing the structural stability requirements, along with EPA's 
proposed reliance on MSHA's size thresholds to determine the 
applicability for the majority of structural stability requirements; 
and (2) the level of detail laid out in the technical criteria 
themselves.
    With respect to the overall regulatory approach, the majority 
supported both the concept of structural stability requirements for 
existing and new CCR surface impoundments, and the adoption of the MSHA 
size threshold for complying with the majority of the structural 
stability requirements. EPA received comments from a number of state 
entities (the Association of State Dam Safety Officials (ASDSO) and the 
Association of State and Territorial Solid Waste Management Officials 
(ASTSWMO)) suggesting that EPA incorporate federal dam safety 
guidelines rather than rely solely on MSHA's dam safety guidelines. 
Commenters were concerned that the MSHA regulations ``only exist to 
protect miners on mine property, and not the downstream public.'' They 
urged that any EPA regulation also include consideration of hazards to 
the downstream public. These commenters also requested that EPA 
``incorporate specific safety standards consistent with the Federal 
Guidelines for Dam Safety,'' referencing standards contained in FEMA 
documents 93, 333, 64, 94 and 65.
    Little support was expressed for the alternative strategies 
presented in the proposal for addressing structural stability. Some 
comments were received suggesting additional alternatives. One 
commenter suggested that EPA consider limiting the volume of ``primary 
containment ponds'' to 10 acre-feet, reasoning that this provision 
would likely eliminate much of the concern regarding catastrophic 
failures, like TVA, and actually reduce the amount of slurry released 
in the event of a structural failure. Other commenters argued that EPA 
should limit the structural requirements to CCR surface impoundments 
both meeting the proposed size threshold and having a hazard potential 
classification of ``high'' or ``significant'' hazard potential rating 
based on FEMA's criteria for dam safety.\78\ Commenters argued that a 
failure of a CCR surface impoundment with a ``low hazard potential 
classification'' posed only a low risk for on-site economic or 
environmental losses and would avoid the imposition of costly, 
arbitrary and unnecessary regulatory burdens on the owner or operator. 
In addition, commenters contended that this regulatory approach would 
be consistent with many state dam regulatory programs that apply dam 
integrity standards only to ``high'' or ``significant'' potential 
hazard facilities and would promote consistency with existing state 
controls.\79\ Several commenters also suggested that EPA consider 
adding regulatory language or preamble discussion to assist owners or 
operators of CCR surface impoundments in interpreting the specific 
technical requirements in the regulation.
---------------------------------------------------------------------------

    \78\ See: Federal Guidelines for Dam Safety: Hazard Potential 
Classification for Dams, Federal Emergency Management Agency 
(``FEMA'') (reprinted January 2004). Under the FEMA dam safety 
classification system, a ``low hazard potential classification'' 
means that failure or mis-operation of the impoundment ``results in 
no probable loss of human life and low economic and/or environmental 
losses. Losses are principally limited to owner's property.''
    \79\ See e.g., New Mexico Rules and Regulations Governing Dam 
Design, Construction and Dam Safety (e.g., requiring dam site 
security, an instrumentation plan for monitoring and evaluating dam 
performance, and an operation and maintenance manual and emergency 
action plan only for dams with a high or significant hazard 
potential); see also NMAC sections 19.25.12.11(G)-(J).
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    EPA disagrees with the suggestion that the Agency finalize a 
mandatory size limitation for operating CCR surface impoundments. While 
limiting the volume of CCR surface impoundments to ten acre-feet would 
limit the volume of CCR released in the event of a structural failure, 
limiting the size of CCR surface impoundments to 10 acre-feet may not 
always be practicable; nor does EPA believe that such a restriction is 
truly necessary to ensure that the section 4004(a) standard will be 
met. Many CCR surface impoundments are much larger than ten acre-feet 
and have been operating for many years without a structural failure. 
While EPA acknowledges that this fact in no way guarantees that a 
failure will not occur, the Agency is convinced that the implementation 
of all of the combined regulatory requirements in this rule (e.g., 
location criteria, structural integrity, inflow design flood controls 
and inspection requirements) provides the necessary safeguards that 
will ensure that CCR surface impoundments are designed, constructed, 
operated, and maintained to minimize the risks associated with a 
catastrophic release of impounded CCR due to structural failure. While 
limiting the size of CCR surface impoundments will reduce risks because 
there will be a lower volume of waste in the unit, the Agency is not 
convinced that, in practice, such a requirement would meaningfully 
reduce the risks at many facilities. EPA expects that such a 
restriction would only cause facilities to construct either several 
small units or a multi-unit system. Failure of one unit can lead to 
progressive failure of other units in the system, and thus, ultimately 
this may not reduce the total volume of waste that could be released 
into the environment. EPA also disagrees that structural stability 
requirements should only apply to ``high'' or ``significant'' potential 
hazard facilities. Similarly, EPA disagrees with commenters that 
structural integrity requirements should only apply to owners or 
operators of CCR surface impoundments that both meet the specified size 
criteria and have either a high hazard or significant hazard potential 
classification. Even for CCR units with a low hazard potential 
classification, EPA is still concerned with the risk to human health 
and the environment from any structural failure of a CCR unit. As 
discussed previously in Unit VI.C of this document, the environmental 
effects of the failure of even a low hazard potential impoundment can 
still be significant, given the size of these units, the nature of the 
material in the unit, and the potential volumes that could be released. 
Contamination of surface waters and groundwater resources is still a 
significant threat when CCR units of this size fail, irrespective of 
the lower likelihood that a release will affect human health, as 
reflected in the low hazard potential classification. Consequently, one 
focus of this rule is preventing any release, catastrophic or 
otherwise, of CCR to the environment, and limiting all structural 
stability requirements commenters suggested would be inconsistent with 
this goal.
    The Agency agrees that the final regulation should incorporate 
provisions that address the hazards to the downstream public. 
Accordingly, the final rule incorporates a number of provisions 
consistent with the FEMA Guidelines, including a requirement that 
owners and operators know each CCR unit's hazard potential 
classification, as this is part of owners and operators' responsibility 
to actively ensure the integrity of their CCR unit(s) and that their 
operations do not endanger human health or the environment. EPA also 
agrees that the requirements should be differentiated based on the 
potential severity of the consequence posed by the unit's failure, and 
therefore the hazard potential can be relevant in determining the 
stringency of particular requirements. However, the hazard potential 
is, at best, only an indicator of the potential damage that may be 
incurred from the

[[Page 21376]]

structural failure of the unit, and so EPA has generally not relied on 
hazard potential as the sole basis for determining the structural 
integrity requirements that are necessary for a CCR unit.\80\ Although 
the hazard potential classification can serve as a proxy for the amount 
of water and CCR that could potentially be released to the environment 
in the event of a CCR surface impoundment failure, the amount of water 
and CCR potentially released is more directly correlated to the actual 
height and storage volume of the CCR surface impoundment. In addition, 
it is widely recognized that the hazard potential classification of an 
individual unit can often fail to encompass the overall magnitude of a 
release on human health and the environment. CCR surface impoundments 
can frequently be part of a facility's run-off system that is 
responsible for routing surface waters to a drainage basin or 
watershed. As previously discussed, the failure of a CCR unit that is 
part of such a system has the potential to inundate downstream surface 
water units and water bodies, resulting in progressive failures of 
other units, including other CCR surface impoundments at the facility, 
which in turn can have a much greater environmental impact than the 
failure of just the one unit for which a hazard potential 
classification was made. Using a ``height and/or volume'' threshold to 
determine the applicability of the structural integrity criteria 
ensures that CCR units with the potential to cause these progressive 
failures in downstream surface water management units are appropriately 
overseen and regulated. CCR surface impoundments exceeding a specified 
height and/or capacity threshold also pose a higher degree of risk of 
release of CCR to the environment than other types of CCR surface 
impoundments (e.g., incised or ``small'' CCR units). For all of these 
reasons, the size of the CCR unit, rather than the hazard potential 
classification, is the best indicator of potential severity of release 
of CCR to the environment and should therefore be the primary basis on 
which structural integrity criteria are applied. As such, EPA is 
promulgating, as proposed, a regulatory strategy that establishes some 
requirements for all CCR surface impoundments, but relies primarily on 
size as the basis for determining the majority of the specific 
technical criteria for minimizing risk from structural failure.
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    \80\ For example, EPA relied on hazard potential to trigger the 
requirement for an Emergency Action Plan, which will identify the 
actions necessary to minimize damage to life and property. As damage 
to life and property are the factors directly addressed in hazard 
potential classification, reliance on the classification is an 
appropriate determinant for this requirement.
---------------------------------------------------------------------------

    Regarding the second major issue presented in the comments, as 
noted previously, EPA received comments requesting the Agency to 
provide either more specific regulatory language or further guidance in 
the preamble, so that parties could certify that the CCR surface 
impoundment met the rule's overall performance standard. Commenters 
contended that guidance would be particularly critical if EPA did not 
establish more specific technical criteria, as owners or operators will 
be vulnerable to lawsuits for non-compliance. In addition, state 
officials requested that EPA adopt more specific standards consistent 
with those adopted under FEMA's Federal Guidelines for Dam Safety. As 
discussed throughout this section in more detail, EPA has adopted 
clarifications to the regulation, particularly in the sections on 
structural stability and safety factors, to more precisely lay out the 
specific technical standards that are considered to be the ``generally 
accepted and recognized good engineering practices'' that must be met. 
EPA relied extensively on existing MSHA requirements, FEMA's Federal 
Guidelines for Dam Safety, and guidance issued by the U.S. Army Corps 
of Engineers, as they were applied throughout EPA's Assessment Program, 
to supplement the technical detail originally contained in the proposed 
rule. EPA has also modified the criteria, where necessary, so they 
better reflect the information and experience developed through the 
Assessment Program, e.g., the engineering criteria used to evaluate the 
CCR surface impoundments and to make recommendations to improve the 
structural stability of the units.
    In this rule, the Agency is finalizing structural integrity 
criteria to ensure that CCR surface impoundments are designed, 
constructed, operated, and maintained in a manner that ensures the 
structural integrity of the CCR surface impoundment throughout its 
active life (i.e., through closure of the CCR unit), detects actual or 
potential releases of CCR as early as practicable, and prevents 
catastrophic failures. Many of the requirements have been adopted 
without revision from the proposed rule for some requirements, however, 
as noted EPA has provided additional language to clarify the final 
regulation. These clarifications have been made in response to comments 
urging EPA to finalize regulatory requirements that were more precise 
or sufficiently objective (i.e., a specific standard of performance) to 
allow a qualified professional engineer to reasonably certify that the 
requirements of the rule have been met. These specific regulatory 
clarifications are discussed throughout this section.
    A further change is that the final rule requires facilities to 
periodically reassess several elements of the structural integrity 
performance standards (i.e., re-assess every five years). Finally, in 
contrast to the programs established by MSHA and FEMA, the final rule 
establishes certain minimum requirements for all CCR surface 
impoundments. This is based on the fact that, unlike the dams regulated 
under other federal programs, the material in all CCR units is harmful, 
so even small releases can present environmental and human health 
concerns. But the majority of the structural integrity requirements 
vary depending on whether the CCR surface impoundment or lateral 
expansion exceeds particular size thresholds. The rulemaking record 
clearly demonstrates that these larger CCR surface impoundments present 
a greater risk of catastrophic failure, and therefore require a more 
robust set of regulatory requirements to ensure their continued 
structural integrity. The final rule's implementation of a size 
threshold for structural integrity requirements is consistent with the 
approach taken by the majority of dam safety programs and regulation.
    These modifications are being made to better reflect the 
protections necessary to ensure that: (1) Structural integrity is 
maintained throughout the operational life of a CCR unit; and (2) the 
risk of catastrophic failure is minimized. The changes being made in 
this rule have been directly influenced by comments received, the 
observations and the conclusions drawn from EPA's Assessment Program, 
and the recommendations made by both MSHA and FEMA regarding dam 
safety. They are also generally consistent with the regulatory 
requirements of many other state and other federal agencies regulating 
dam safety.
1. Overview of Technical Criteria
    Except for incised units, owners or operators of all existing and 
new CCR surface impoundments and any lateral expansion of these CCR 
units are required to: (1) Place a permanent identification marker on 
or immediately adjacent to the CCR units with the name associated with 
the CCR unit and the name of the owner or operator of the CCR unit; (2) 
conduct an initial hazard potential assessment to determine the current 
hazard potential classification of

[[Page 21377]]

the CCR unit; (3) conduct periodic (i.e., every five years) hazard 
potential re-assessments; (4) develop an Emergency Action Plan (EAP) if 
the hazard potential classification of the CCR unit is classified as 
either a high- or significant hazard potential; and (5) maintain the 
CCR unit with vegetated slopes or other forms of slope protection.
    Owners or operators of CCR surface impoundments that either have a 
height of five feet or more and a storage volume of 20 acre feet or 
more, or a height of 20 feet or more are required to comply with the 
following additional structural integrity criteria: (1) Document the 
design and construction of the CCR surface impoundment; (2) conduct an 
initial structural stability assessment; (3) conduct an initial safety 
factor assessment; and (4) conduct periodic (not to exceed five years) 
structural stability and safety factor assessments.\81\ Owners and 
operators of CCR units that fail to make the safety factor assessment 
or fail to meet the factors of safety specified in the rule must stop 
placing CCR in the unit and initiate closure.
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    \81\ Height means the vertical measurement from the downstream 
toe of the CCR surface impoundment at its lowest point to the lowest 
elevation of the crest of the CCR surface impoundment.
---------------------------------------------------------------------------

    The structural integrity requirements of the final rule require the 
compilation of construction history of the existing CCR surface 
impoundment within one year of the effective date of the rule.
    Within two months of the effective date of the rule, the structural 
integrity requirements (Sec.  257.73) state that the owner or operator 
must install a permanent marker on the existing CCR surface 
impoundment. This timeframe is being promulgated as proposed, as EPA 
did not receive comments on the timeframe for installation of a 
permanent marker.
2. Structural Integrity Requirements Applicable to All CCR Surface 
Impoundments
a. Hazard Potential Classification Assessments
    A hazard potential classification provides an indication of the 
potential for danger to life, development, or the environment in the 
event of a release of CCR from a surface impoundment. In this rule, an 
owner or operator of any existing or new CCR surface impoundment or any 
lateral expansion of a CCR surface impoundment must determine which of 
the following hazard potential classifications characterizes their 
particular CCR unit.\82\ These classifications are: a high hazard 
potential CCR surface impoundment, a significant hazard potential CCR 
surface impoundment; and a low hazard potential CCR surface impoundment 
and are defined as follows:
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    \82\ Incised CCR surface impoundments are not required to 
perform a hazard potential classification assessment because hazard 
potential classifications are based on the failure of a dam, diked 
surface impoundment, or other water-retaining structure and the 
adverse incremental impacts that may result from the failure. 
Because incised CCR surface impoundments, as defined in this rule, 
do not have a diked portion which may fail, the incised CCR surface 
impoundment cannot have a hazard potential classification. This 
final rule covers CCR surface impoundment failures and releases due 
to other potential failure modes (i.e., which do not pose an 
immediate catastrophic threat to human health or the environment), 
such as a release through the liner of the unit or through failure 
of underlying structures, in the location restrictions, design 
criteria, and operating criteria of the rule.
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     High hazard potential CCR surface impoundment means a 
diked surface impoundment where failure or mis-operation will probably 
cause loss of human life.
     Significant hazard potential CCR surface impoundment means 
a diked surface impoundment where failure or mis-operation results in 
no probable loss of human life, but can cause economic loss, 
environmental damage, disruption of lifeline facilities, or impact 
other concerns.
     Low hazard potential CCR surface impoundment means a diked 
surface impoundment where failure or mis-operation results in no 
probable loss of life and low economic and/or environmental losses. 
Losses are principally limited to the surface impoundment's owner's 
property.
    Owners and operators of all CCR surface impoundments must determine 
each unit's hazard potential classification through a hazard potential 
classification assessment. Hazard potential classification assessments 
must be certified by a qualified professional engineer and 
documentation must be provided that supports the basis for the current 
hazard potential rating. An initial hazard potential assessment must be 
conducted within one year of the effective date of the rule for 
existing units and prior to the initial receipt of CCR in the unit for 
new units or lateral expansions. Hazard potential classifications, 
structural stability assessments, and safety factor assessments require 
significant planning and coordination, such as detailed site-work and 
investigations, modeling and analysis, design and construction planning 
and implementation, and post-construction investigation. Many of these 
efforts take several months to complete, compounded by the fact that 
much of the work cannot be completed in cold-weather or heavy-rain 
seasons.
    As commenters noted, it is imperative that the owner or operator 
maintain a current assessment of a unit's hazard potential 
classification, rather than develop a single one-time classification 
``for which the facility was designed.'' (See proposed Sec.  
257.71(d)(10).) Moreover, FEMA recommends that a unit's hazard 
potential classification should be reviewed no less frequently than 
every five years in order to take into account changes in the factors 
that are the basis for which a hazard potential classification is made 
(e.g., changed reservoir or downstream development).\83\ Based on this 
information, EPA determined that a periodic reassessment of a CCR 
surface impoundment's hazard potential classification is a necessary 
component in maintaining the accuracy of the unit's hazard potential 
classification, as well as the overall safety of the unit. 
Consequently, EPA is requiring the owner or operator of a CCR surface 
impoundment to reassess the hazard potential classifications of their 
CCR unit and to have that classification, certified by a qualified 
professional engineer, at least every five years.
---------------------------------------------------------------------------

    \83\ See: Federal Guidelines for Dam Safety: Hazard Potential 
Classification for Dams, Federal Emergency Management Agency 
(``FEMA'') (reprinted January 2004). Under the FEMA dam safety 
classification system, a ``low hazard potential classification'' 
means that failure or mis-operation of the impoundment ``results in 
no probable loss of human life and low economic and/or environmental 
losses. Losses are principally limited to owner's property.''
---------------------------------------------------------------------------

    EPA has continued to rely on FEMA requirements as the basis for 
general CCR surface impoundment safety requirements, e.g., inflow 
design flood selection, inspection criteria, earthquake analyses and 
design for several reasons: (1) Structural failure risks for CCR 
surface impoundments are similar to the risks from the larger dam 
universe for which FEMA intends its guidance; and (2) risks to 
downstream development from CCR surface impoundment failures are equal 
or similar to those presented by other types of dams' failures.
    In this rule, hazard potential classifications define the 
consequences in the event of a failure of a CCR surface impoundment. 
The classification is separate from the structural stability of a CCR 
unit or the likelihood of the impoundment failing. A surface 
impoundment that meets or exceeds all of the structural stability 
criteria and safety factors of this rule would still be classified as 
``high hazard potential'' if, in the event of failure, loss of life 
would be likely to occur.

[[Page 21378]]

    The hazard potential classification of the CCR surface impoundments 
is an essential element in determining how to properly design, 
construct, operate, and maintain a CCR surface impoundment. As such, 
the final rule bases the stringency of some technical requirements, in 
part, on the potential for adverse impacts on the failure of the CCR 
unit, as quantified by the hazard potential classification of this 
rule. Specifically, the requirements become more stringent as the 
potential for loss of life and/or property damage increases. This is 
reflected in both the criteria established under the structural 
stability assessments, .e.g., where the combined capacity of all 
spillways must adequately manage flow during and following peak 
discharge from the specified inflow design flood based on the hazard 
potential classification of the unit--and in the hydrologic and 
hydraulic capacity requirements, which are similarly specified based on 
the hazard potential classification of the CCR unit (see Sec. Sec.  
257.73(d)(2)(v); 257.74(d)(2)(v) and 257.82 respectively).\84\ 
Additionally, high and significant hazard potential CCR surface 
impoundments must develop a written Emergency Action Plan which 
establishes emergency action procedures in the event of a previously 
defined emergency.
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    \84\ A high-hazard potential impoundment, for example, must be 
designed with sufficient spillway capacity to manage flow from the 
probable maximum flood, whereas a low hazard potential unit need 
only account for a 100 year flood.
---------------------------------------------------------------------------

b. Emergency Action Plan
    An Emergency Action Plan (EAP) is a document that identifies 
potential emergency conditions at a CCR surface impoundment and 
specifies actions to be followed to minimize loss of life and property 
damage. Typically an EAP includes: (1) Actions the owner or operator 
will take to moderate or alleviate a problem at the CCR unit; (2) 
actions the owner or operator will take, in coordination with emergency 
management authorities, to respond to incidents or emergencies related 
to the CCR surface impoundment; (3) procedures owner or operators will 
follow to issue early warning and notification message to responsible 
downstream emergency management authorities; (4) inundation maps to 
allow owners and operators of the CCR unit and emergency management 
authorities to identify critical infrastructure and population-at-risk 
sites that may require protective measures, warning and evacuation 
planning; and (5) delineation of the responsibilities of all those 
involved in managing an incident or emergency and how the 
responsibilities should be coordinated and implemented.\85\ As FEMA 
guidance suggests, and EPA reiterates here, the level of detail in the 
EAP should be commensurate with the potential impact of a surface 
impoundment failure or other operational incident (e.g., its hazard 
potential classification). A surface impoundment with low potential 
hazard impact should not require an extensive evaluation or be subject 
to an extensive planning process, while high-hazard and significant 
hazard surface impoundments would typically require a much larger 
emergency planning effort. In addition, high hazard and significant 
hazard surface impoundments tend to involve more entities that must 
coordinate responsibilities and greater efforts would generally be 
necessary to effectively respond to an incident with such a surface 
impoundment than to a similar incident involving a low-hazard surface 
impoundment. As such, every EAP must be tailored to specific site 
conditions.
---------------------------------------------------------------------------

    \85\ See: ``Federal Guidelines for Dam Safety: Emergency Action 
Planning for Dams,'' FEMA 64/July 2013.A.
---------------------------------------------------------------------------

    EPA is promulgating, as proposed, a provision that requires any CCR 
surface impoundment that is determined by the owner or operator, 
through the certification by a qualified professional engineer, to be 
either a high hazard potential CCR surface impoundment or a significant 
hazard potential CCR surface impoundment to prepare and maintain a 
written EAP. While EPA agrees that the level of detail contained in an 
EAP should be commensurate with its hazard potential rating, EPA has 
concluded that at a minimum, the EAP must: (1) Define responsible 
persons and the actions to be taken in the event of a CCR surface 
impoundment-safety emergency; (2) provide contact information for 
emergency responders, including a map which delineates the downstream 
area which would be affected in the event of a failure and a physical 
description of the CCR surface impoundment; (3) include provisions for 
an annual face-to-face meeting or exercise between representatives of 
the owner or operator of the CCR unit and the local emergency 
responders; and (4) define conditions that initiate implementation of 
the EAP and define emergency response actions which must be implemented 
upon the detection of these conditions, including all persons 
responsible for the implementation of the emergency response actions. 
The first three of these four requirements were proposed as part of the 
EAP and are being promulgated without revision. The fourth requirement, 
which requires facilities to explicitly define the conditions by which 
the EAP is activated, was inadvertently omitted from the proposal, and 
is being added to the final rule to ensure that the EAP includes at 
least the basic requirements necessary to function effectively.
    The owner or operator must amend the written EAP whenever there is 
a change in conditions that would substantially affect the written EAP 
in effect, e.g., change in personnel, change in emergency responder 
contact information, a change in the CCR surface impoundments' 
designation from a significant-hazard potential classification to a 
high-hazard potential classification, or the vertical expansion of the 
CCR unit (i.e., increase in the amount of CCR that potentially could be 
released.) Consistent with the requirements for hazard potential 
classification reassessments, the Agency is requiring, at a minimum 
that the EAP be reassessed at least every five years. If an owner or 
operator determines that, as part of it periodic hazard potential re-
assessment that the unit no longer is classified as a high-hazard or a 
significant-hazard potential classification, but is now classified as a 
low hazard potential CCR surface impoundment, then the owner or 
operator of the CCR unit is no longer subject to the requirement to 
prepare and maintain an EAP, effective when such documentation is 
placed into the facility's operating record. If, however, during the 
reassessment effort it is determined that an existing CCR unit 
classified as a low hazard potential has been re-classified as either a 
significant-hazard or high-hazard potential, the owner or operation 
must prepare an EAP for the CCR unit within six months of completing 
such a periodic hazard potential re-assessment.
    Although the owner or operator is responsible for developing and 
maintaining the EAP, which must be certified by a qualified 
professional engineer, the plan should be developed and implemented in 
close coordination with all applicable emergency management 
authorities, including the appropriate local, state, and federal 
authorities. Generally, these coordination efforts, along with the EAP, 
provide emergency management authorities with the necessary information 
to facilitate the implementation of their responsibilities, and so, it 
is vital that the development of the EAP be coordinated with emergency 
responders and other entities, agencies, and jurisdictions, as

[[Page 21379]]

appropriate. After the initial EAP has been developed and placed in the 
operating record and on the owner or operator's internet site, it 
should be periodically reviewed and updated on a regular basis, as it 
can become outdated and ineffective. While the Agency is only requiring 
the EAP to be re-assessed every five years, it is recommended that the 
EAP be reviewed at least annually for appropriateness, accuracy, and 
adequacy so as to remain current. EPA recommends that the EAP be 
promptly updated to address changes in personnel, contact information 
and/or significant changes to the facility or emergency procedures. 
Even if no revisions are necessary, the review should be documented.
    The initial EAP must be prepared within 18 months from the 
effective date of the rule. In order to prepare an EAP, the owner or 
operator must accurately and comprehensively identify potential failure 
modes and at-risk development, and therefore completion of the 
emergency action plan needs to follow the completion of the initial 
hazard potential classification, structural stability assessment, and 
safety factor assessments, during which this information will be 
generated.
c. Vegetated Slopes of Dikes and Surrounding Areas
    EPA proposed to require both new and existing CCR surface 
impoundments that exceed the MSHA size thresholds to document the slope 
protection measures that have been adopted and to compute the minimum 
factors of safety for slope stability, in order to support the 
certification from an independent professional engineer that the unit 
has been designed in accordance with ``generally accepted engineering 
standards.'' EPA is promulgating the requirement that all CCR surface 
impoundments have adequate slope protection because EPA determined 
through the Assessment Program that slope protection is an essential 
element in preventing slope erosion and subsequent deterioration of CCR 
unit slopes. EPA is requiring slope protection for all units, not just 
units exceeding the size threshold of the final rule, because EPA has 
identified that slope protection on CCR units is a generally accepted 
good practice which reduces the occurrence of erosion, degradation of 
surface waters due to run-off from the CCR unit, enhances slope 
stability, and that vegetated cover is an easily accomplished practice 
in the vast majority of climates where CCR surface impoundments are 
located. In conducting the Assessment Program, the protective cover of 
slopes of the CCR surface impoundment was determined to be relevant to 
the overall condition rating of all units, irrespective of size. This 
is consistent with FEMA guidance, which also lays out specifications 
for the ideal vegetative cover for a dam. EPA has adopted this 
requirement to be consistent with its findings from the Assessment 
Program, and in response to comments, and has elaborated on the slope 
protection measures necessary to achieve the factors of safety. The 
final rule provides performance standards drawn primarily from FEMA 
guidance, as applied during the Assessment Program.
    All CCR surface impoundments are required to be designed, 
constructed, operated, and maintained with adequate slope protection to 
protect against surface erosion at the site. Slope protection is 
necessary to ensure that dike or embankment erosion does not occur. 
Additionally, slope protection is required of all CCR surface 
impoundments to maintain the stability of the CCR surface impoundment 
slope under rapid drawdown events \86\ and low pool conditions of water 
bodies that may abut the CCR surface impoundment and are outside the 
control of the owner or operator, e.g., a natural river which the 
slopes of the CCR surface impoundment run down to and abut. The slope 
protection can act as a stabilizer in the slope of the embankment 
during rapid drawdown events. Adequate slope protection can be achieved 
in most climates through simple vegetation, typically a healthy, dense 
stand of low-growing grass, or other similar vegetative cover. In arid 
climates where the upkeep of vegetation is inhibited, alternate forms 
of slope protection, including rip-rap, or rock-armor is typically 
used. Additional slope protective measures are available and effective 
in certain circumstances, including but not limited to rock, wooden 
pile, or concrete revetments, vegetated wave berms, concrete facing, 
gabions, geotextiles, or fascines.
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    \86\ This rapid drawdown is not included in the rule's factors 
of safety assessments. The protection against rapid drawdown 
requirement of this provision is concerned with the rapid drawdown 
of adjacent water bodies acting upon the downstream slope of the CCR 
surface impoundment rather than the rapid drawdown of the impounded 
reservoir of the CCR surface impoundment acting upon the upstream 
slope of the CCR surface impoundment.
---------------------------------------------------------------------------

    The owner or operator must ensure that the slopes of the CCR 
surface impoundment are protected from erosion by appropriate 
engineering slope protection measures. It is recommended throughout 
embankment technical literature that vegetative cover not be permitted 
to root too deeply, precipitating internal embankment issues. The rule 
requires a vegetative cover limit to prevent the establishment of 
rooted vegetation, such as a tree or a bush on the CCR surface 
impoundment slope. EPA has concluded that a vegetative cover of no more 
than six inches above the face of the embankment is adequate and is the 
uppermost limit for vegetative cover height for this final rule. In 
developing this requirement, EPA was strongly influenced by information 
contained in the FEMA document entitled, ``Technical Manual for Dam 
Owners: Impacts of Plants on Earthen Dams'' \87\ in determining an 
appropriate vegetative cover height for CCR surface impoundments. Six 
inches represents a vegetative height which prevents any trees, bushes, 
or shrubbery from rooting deeply enough to warrant additional removal 
measures outside of simple mowing. Furthermore, the height prescribed 
by the final rule represents a maximum height of vegetative cover to 
allow for adequate observation of the slope of the CCR unit during 
inspection. Vegetative cover in excess of six inches above the slope of 
the dike would prevent the adequate observation of the slope of the CCR 
unit and detection of structural concerns such as animal burrows and 
minor sloughs, amongst others concerns. Consistent with FEMA guidance, 
as applied during the Assessment Program, other slope protection, such 
as rock armoring or vegetated berms, would also be considered 
adequate.\88\
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    \87\ http://www.fema.gov/media-library-data/20130726-1446-20490-2338/fema-534.pdf.
    \88\ http://www.fema.gov/media-library-data/20130726-1446-20490-2338/fema-534.pdf.
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3. Structural Integrity Criteria Applicable to CCR Surface Impoundments 
Exceeding a Specific Size Threshold
    The structural integrity criteria discussed in this section of the 
preamble apply to existing and new CCR surface impoundments and any 
lateral expansion with: (1) A height of five feet or more and a storage 
volume of 20 acre-feet or more; or (2) a height of 20 feet or more. The 
rule defines height as the vertical measurement from the downstream toe 
of the CCR surface impoundment at its lowest point to the lowest 
elevation of the crest of the CCR surface impoundment. The downstream 
toe is defined as the junction of the downstream slope or face of the 
CCR surface impoundment with the ground surface. This final rule 
considers the lowest elevation of the crest of the CCR

[[Page 21380]]

surface impoundment to be the maximum storage elevation of the 
reservoir or pool of the CCR unit, e.g., the invert of the lowest-
elevation spillway. EPA is implementing this size threshold because it 
comports with thresholds established by other federal and state 
agencies regulating dam integrity and/or safety. Specifically, for the 
implementation of the size threshold of this final rule, EPA relied on 
the identical size parameters, i.e., height of five feet and capacity 
of 20 acre-feet, which is promulgated in MSHA coal slurry impoundment 
regulations in 30 CFR 77.216.
    In the proposed rule, EPA used the size cut-off promulgated by MSHA 
in their dam safety requirements for coal slurry impoundments at 30 CFR 
part 77. In proposing this cut-off, EPA reasoned that the MSHA 
requirements affecting coal slurry impoundments were directly 
applicable and relevant to CCR surface impoundments and provided a size 
threshold that, when applied to the rule's structural integrity 
criteria, would generally meet RCRA's mandate to ensure protection of 
human health and the environment by minimizing the potential for 
catastrophic failure. Specifically, EPA proposed that surface 
impoundments: (1) Impounding CCR to an elevation of five feet or more 
above the upstream toe of the structure and can have a storage volume 
of 20 acre-feet or more; or (2) impounding CCR to an elevation of 20 
feet or more above the upstream toe of the structure would be subject 
to the structural stability criteria. EPA also proposed to define 
upstream toe as the junction of the upstream slope of the dam with the 
ground surface, with the height of the CCR unit measured from the 
upstream toe or water-borne toe of the CCR unit.
    While little comment was received on adopting this size threshold 
or the accompanying definition of upstream toe, the Agency was 
concerned that the size threshold presented in the proposed rule did 
not reflect standard measuring protocols used by other federal agencies 
and the dam sector in determining the size of a dam or, in the case of 
this rule, surface impoundment. Of particular concern to the Agency was 
the fact that EPA's own Assessment Program was measuring the height of 
a CCR unit from the downstream toe rather than the upstream toe, which 
was specified in the MSHA regulatory requirement and the subsequent CCR 
proposed rule.
    A review of MSHA, FEMA and the USACE regulations and guidance, as 
well as the guidance of several state agencies that oversee dam safety, 
revealed that dam or surface impoundment height is more appropriately 
measured from the downstream and not the upstream toe of the unit. EPA 
based this conclusion on the near-universal position of dam safety 
guidance that the downstream slope height of the dike is of primary 
concern in the design, construction, operation, and maintenance of the 
dam or surface impoundment. Virtually all of the dam safety 
regulations, including state and federal guidance and regulations, that 
EPA reviewed considered measured dam height to be taken from the 
downstream slope of the dike. Some of these guidance and regulations 
include FEMA ``Federal Guidelines for Dam Safety,'' U.S. Army Corps 
``National Inventory of Dams,'' and MSHA Metal and Nonmetal Tailings 
and Water Impoundment Inspection requirements in 30 CFR part 56 and 
Sec.  57.20010.\89\ This information, coupled with the information on 
the methodology used in the Assessments Program, convinced the Agency 
that a revised description of the CCR surface impoundment size cutoff 
was necessary, specifically requiring the height of the CCR unit to be 
measured from the downstream toe.
---------------------------------------------------------------------------

    \89\ http://www.msha.gov/regs/complian/PILS/2013/PIL13-IV-01.asp.
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a. Design and Construction Information
    The first element of the structural integrity criteria applicable 
to CCR units exceeding the specified size threshold requires the owner 
or operator to compile and place in the operating record design and 
construction information pertaining to the CCR unit. Among other 
things, this provision requires the following documentation to be 
provided by the owner or operator: (1) The name of the owner or 
operator of the unit; (2) the name of the unit; and (3) any 
identification number assigned by the state. In addition, it requires 
that the owner or operator identify: (5) The location of the CCR unit 
on a U.S. Geological Survey Map or a topographic map of equivalent 
scale; (6) provide dimensional drawings of the CCR unit with pertinent 
engineering structures and appurtenances identified; (7) describe the 
purpose of the CCR unit; and (8) identify the name and size of the 
watershed affecting the CCR unit, if any. Detailed information is also 
required documenting: (9) The design and construction of the unit 
including dates and descriptions of each zone or stage constructed; 
(10) instrumentation used to monitor the operation of the CCR unit, 
(11) spillway and diversion design descriptions and construction 
specifications; and (12) provisions for surveillance, maintenance and 
repair of the CCR unit.
    While these requirements apply to both existing and new CCR surface 
impoundments, existing CCR surface impoundments are required to compile 
this information only ``to the extent available,'' within one year of 
the effective date of the rule. Conversely, new CCR surface 
impoundments or any lateral expansion must compile all of the 
information listed prior to the initial receipt of CCR. For existing 
CCR surface impoundments, EPA acknowledges that much of the 
construction history of the surface impoundment maybe unknown or lost. 
EPA's Assessment Program confirmed that many owners or operators of CCR 
units did not possess documentation on the construction history or 
operation of the CCR unit. Information regarding construction 
materials, expansions or contractions of units, operational history, 
and history of events was frequently difficult for the owners or 
operators to obtain. The Assessment Program also confirmed the Agency's 
initial assumption that this information, in many instances, will be 
difficult to compile. Therefore, in this rule, EPA is using the phrase 
``to the extent available'' and clarifying that the term requires the 
owner or operator to provide information on the history of construction 
only to the extent that such information is reasonably and readily 
available. EPA intends facilities to provide relevant design and 
construction information only if factual documentation exists. EPA does 
not expect owners or operators to generate new information or provide 
anecdotal or speculative information regarding the CCR surface 
impoundment's design and construction history.
    There are several other requirements under the design and 
construction criteria requiring clarification. First, the Agency is 
amending the requirement that all dimensional drawings of the CCR unit 
(see Sec.  257.73(b)(vii) and Sec.  257.74(b)(vii)) use a uniform scale 
of one inch equals 100 feet. After further consideration, EPA has 
deleted this requirement and has replaced the proposed scale of 1 inch 
equals 100 feet with the phrase ``at a scale that details engineering 
structures and appurtenances relevant to the design, construction, 
operation, and maintenance of the CCR unit.'' EPA made this change in 
response to comments arguing that this level of detail was unnecessary. 
EPA agrees that, given the extremely large variety in the size of CCR 
units, a prescriptive scale for all drawings of all CCR units is not 
necessary in many cases; this level of detail would be excessive for 
most

[[Page 21381]]

units. The Agency is also clarifying, (see Sec.  257.73(b)(2) and Sec.  
257.74(b)(2)) that if an owner or operator determines that a 
significant change has occurred in the information/documentation 
previously compiled under this provision, the owner or operator must 
update the relevant information and place it in the operating record.
b. Types of Assessments
    A second element of the structural integrity criteria is the 
requirement for specific technical assessments of the CCR unit. 
Consistent with the requirements outlined in the proposed rule, two 
technical assessments are required for all CCR units exceeding the 
specified size threshold: (1) A structural stability assessment; and 
(2) a safety factor assessment. The owner or operator of an existing 
CCR surface impoundment is required to conduct an initial assessment 
addressing both structural stability and safety factors within one year 
of the effective date of the rule. New CCR surface impoundments or any 
lateral expansion of a CCR unit are required to complete the initial 
assessment prior to placing CCR into the unit. Following the initial 
assessments, EPA is also requiring periodic re-assessments of both a 
CCR surface impoundment's structural stability and factors of safety. 
EPA proposed to require an annual recertification, but in a departure 
from the proposed rule, EPA is only requiring these re-assessments to 
be conducted on a regular basis, not to exceed once every five years. 
In making this regulatory change, the Agency has relied heavily on the 
dam safety guidance established by FEMA in the document titled, Federal 
Guidelines for Dam Safety that a formal inspection, including ``. . . a 
review to determine if the structures (i.e., CCR surface impoundments) 
meet current accepted design criteria and practices . . .'' be taken at 
an interval not to exceed five years. EPA has interpreted this guidance 
to be applicable to both the structural stability assessment and the 
safety factor assessment.
    A demonstration must be completed within the assessment period for 
the specific type of assessment. This means that, within this timeframe 
the owner or operator must demonstrate that the CCR unit meets all of 
the requirements of each type of assessment, as certified by a 
qualified professional engineer. It also means that the owner or 
operator must have taken all measures necessary to bring the unit into 
compliance with all of the requirements for assessments of this final 
rule within the assessment period. If the owner or operator cannot 
demonstrate that the unit meets these factors of safety (or otherwise 
fails to comply with the structural stability requirements) within the 
appropriate timeframe, the unit must initiate closure.
i. Periodic Structural Stability Assessments
    In order to ensure the proper upkeep and operation of the CCR unit, 
the owner or operator must demonstrate that the CCR surface impoundment 
has been designed, constructed, operated and maintained to provide 
structural stability. Specifically, consistent with the proposal, the 
final rule requires the owner or operator to demonstrate that the 
design, construction, operation, and maintenance of the CCR surface 
impoundment is consistent with recognized and generally accepted good 
engineering practices for the maximum volume of CCR and water that can 
be impounded therein. As discussed previously, EPA has elaborated on 
this overall performance standard in response to comments from the 
engineers who would be required to make these certifications, urging 
EPA to specify more precisely the standards that must be met. 
Specifically the final rule focuses on the critical structural aspects 
of the CCR surface impoundment that EPA identified in the proposed 
rule, and identifies the minimum elements that a professional engineer 
must provide engineering details on or otherwise address. In certain 
cases, the final criteria identify specific engineering performance 
standards. EPA relied on existing MSHA requirements, FEMA dam safety 
guidance, and guidance issued by the USACE, as applied throughout EPA's 
Assessment Program to develop these criteria. Consistent with the 
proposal, these demonstrations must be certified by a qualified 
professional engineer. Each of these criteria is discussed in more 
detail below.
    In addition to implementing adequate slope protection against 
erosion, which is a structural stability requirement applicable to all 
CCR units, the owner or operator of a CCR surface impoundment exceeding 
the specified size threshold must demonstrate that the unit, including 
any vertical and lateral expansions, is constructed with ``stable 
foundations and abutments.'' A stable foundation is an essential 
element of surface impoundment construction and prevents differential 
settlement of the embankment which can result in adverse internal 
stresses with the embankment cross-section. Soils tend to consolidate 
when subjected to loadings for extended periods, which can lead to 
strain incompatibility, a phenomena which prevents the full development 
of peak strength of the foundation. The stability of foundations and 
abutments can be determined by engineering monitoring, representative 
soil sampling, and modeling. Similarly, cohesion between the abutments 
of the CCR surface impoundment and the embankment of the CCR surface 
impoundment is critical. Frequently, CCR surface impoundments are 
subject to cracking and excessive seepage and piping in the groins 
where the abutment and embankment meet. These adverse conditions may 
lead to further structural deficiencies which threaten the safety of 
the CCR surface impoundment.
    Consistent with general engineering construction methodologies, the 
structural stability assessment also requires the owner or operator to 
determine whether the CCR surface impoundment has been mechanically 
compacted to a density sufficient to withstand the range of loading 
conditions in the CCR unit.\90\ Compaction of a dike or embankment is 
considered essential, as the compaction of soils leads to an increase 
in density and subsequently strength. Soil mechanics theory has 
established that the density of a soil corresponds to the moisture 
content and strength of the soil. The rule requires the owner or 
operator make this determination for all dikes of a CCR surface 
impoundment.
---------------------------------------------------------------------------

    \90\ http://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-2300.pdf.
---------------------------------------------------------------------------

    EPA notes that a number of existing voluntary consensus standards 
are available that can be useful in making this determination. For 
example, ASTM D 698 establishes a performance standard of 95% of the 
maximum standard Proctor density. Similarly, ASTM D 1557 establishes a 
standard of 90% of the maximum modified Proctor density. Alternatively, 
in certain instances, such as soils consisting of more than 30% 
material retained on the \3/4\ in. sieve, Proctor testing is not 
appropriate and the relative density criteria can be met. In such 
cases, EPA recommends a 70% relative density. These specific soil 
compaction criteria are ubiquitous throughout engineering construction 
as sufficient to support engineered works based on the requirements. 
They are also consistent with the standards promulgated by the state of 
New Mexico's dam safety program in order to ensure proper compaction 
during construction of new CCR surface impoundments.
    EPA recognizes that it would be highly difficult for owners or 
operators

[[Page 21382]]

of older units to certify with any certainty that the unit's 
construction meets the specific numeric compaction criteria found in 
the ASTM standards. New units, however, can easily meet these 
standards, and should therefore be designed and constructed to meet the 
numeric compaction criteria.
    The owner or operator must also design, construct, operate, and 
maintain the CCR surface impoundment spillway or spillways with 
appropriate material so as to prevent the degradation of the spillway, 
as well as to ensure that the CCR surface impoundment has adequate 
spillway capacity to manage the outflow from a specific inflow design 
flood. In addition, a demonstration must be made that the CCR surface 
impoundment has been designed, constructed, operated, and maintained 
with inflow design flood controls and/or spillway capacity to manage 
peak discharge during and following inflow design floods. This 
demonstration is required to ensure the CCR surface impoundments will 
have adequate hydrologic and hydraulic capacity to prevent such 
failures as overtopping and excessive internal seepage and erosion. 
Spillways must be designed to withstand discharge from the inflow 
design flood without losing their structural form and leading to 
discharge issues, such as erosion or overtopping of the embankment. 
This requirement is covered in more detail in the hydrologic and 
hydraulic capacity requirements for CCR surface impoundments section of 
this rule.
    EPA is not requiring a facility to include any demonstration 
relating to the potential for rapid, or sudden, drawdown loading 
condition. Rapid or sudden drawdown is a condition in earthen 
embankments in which the embankment becomes saturated through seepage 
in an extended high pool elevation in the reservoir. A threat to the 
embankment emerges when the reservoir pool is drawn down or lowered at 
a rate significantly higher than the excess poor water pressure within 
the embankment can diminish. Typically, rapid drawdown scenarios are 
considered for embankments with reservoirs used for water supply and 
management, emergency reservoirs, or agricultural supply, in which the 
reservoir is rapidly discharged from the structure. In these scenarios, 
a high pool elevation is maintained in the reservoir in storage months. 
Subsequently, the water supply is drawn on in months where there is a 
high demand for the reservoir's contents. This drawing down of the pool 
can affect the structural stability of the unit. However, the 
management of CCR surface impoundments differs from that of 
conventional water supply, emergency, and agricultural reservoirs. The 
only instance of a rapid drawdown of a CCR surface impoundment which 
EPA has identified is in the event of a massive release of the 
reservoir of the CCR surface impoundment due to a failure of the dike 
of the CCR surface impoundment. In this instance, a massive release has 
occurred or is occurring. A subsequent failure of the upstream or 
internal embankment due to this rapid drawdown would only precipitate 
further embankment failure and not any further release of the contents 
of the impoundment, as the contents of the surface impoundment would 
have already been released. In these instances, remediation of a 
failure in a rapidly drawn-down section would be necessary prior to 
filling of the unit, but is not a concern precipitating a release of 
impounded contents.
    A second consideration regarding rapid drawdown, however, is the 
rapid drawdown of a water body adjacent to the slope of the CCR surface 
impoundment which may periodically inundate the slope. Many CCR surface 
impoundments are located in areas in which the downstream slope of the 
CCR surface impoundment runs down to a lake, stream, or river. In such 
instances, rapid drawdown must be considered for the stability of the 
downstream slope of the embankment in the event of a rapid drawdown in 
the lake, stream, or river pool elevation or stage. Because the water 
ponded against the downstream slope of the CCR surface impoundment 
provides a stabilizing load on the slope of the CCR surface 
impoundment, the rapid or gradual loss of this stabilizing force must 
be considered in the analysis of the CCR surface impoundment. The rule, 
therefore, requires that existing and new CCR surface impoundments and 
any lateral expansions of such units with a downstream slope that can 
be inundated by an adjacent water body, such as rivers, streams, or 
lakes, be constructed with downstream slopes that will maintain 
structural integrity in events of low pool or rapid drawdown of the 
adjacent water body. This ensures that the structural integrity of the 
downstream slope of the CCR surface impoundment will be maintained, 
even though the conditions of an adjacent surface water body may be 
outside the owner or operator's control.
ii. Periodic Safety Factor Assessments
    As previously discussed, EPA received comment requesting the Agency 
to supplement the proposed technical criteria to assist owners or 
operators of CCR surface impoundments in interpreting the factor of 
safety determination required by proposed Sec.  257.71(d)(12). EPA 
proposed that facilities compute ``a minimum factor of safety for slope 
stability of the CCR retaining structure(s),'' and to provide the 
methods and calculations used to determine each factor of safety. In 
reviewing the proposed requirement, the Agency agrees that further 
elaboration on the requirement is necessary to ensure that engineers 
can accurately assess a CCR unit's structural stability using factor of 
safety calculations, and would be valuable to ensure a consistent 
national standard. EPA has therefore revised the criteria to be 
consistent with the criteria developed and used to assess these 
impoundments as part of the Assessment Program.
    Accordingly, the final rule requires demonstrations of structural 
integrity using accepted engineering methodologies under specific 
loading conditions. Owners or operators must conduct and have certified 
by a qualified professional engineer, an initial assessment, supported 
by the appropriate engineering calculations, documenting whether the 
CCR unit achieves the following minimum factors of safety: (1) The 
calculated static factor of safety under the long-term, maximum storage 
pool loading condition, which must equal or exceed 1.50; (2) the 
calculated static factor of safety under the maximum surcharge pool 
loading condition, which must equal or exceed 1.40; (3) the calculated 
seismic factor of safety, which must equal or exceed 1.00; and (4) the 
calculated liquefaction factor of safety, which must equal or exceed 
1.20. In addition to the safety factors specified for existing CCR 
surface impoundments, new CCR surface impoundments and any lateral 
expansion must also comply with a fifth safety factor, the calculated 
static factor of safety under the end-of-construction loading 
condition, which must equal or exceed 1.30.
    The minimum static factors of safety are adopted directly from the 
USACE's Engineer Manual EM 1110-2-1902 entitled, ``Slope Stability.'' 
As discussed in more detail in Unit III of this document, EPA relied 
heavily on this manual and applied these specific factors of safety 
during its Assessment Program, and it is widely considered the 
benchmark in the dam engineering community for slope stability and 
methodology and analysis.
    The seismic factor of safety is adopted from review of several dam 
safety guidance documents, including USACE guidance Engineer Circular 
1110-2-6061: Safety of Dams-Policy and Procedures 2204, Engineer 
Circular

[[Page 21383]]

1110-2-6000: Selection of Design Earthquakes and Associated Ground 
Motions 2008, and Engineer Circular 1110-2-6001: Dynamic Stability of 
Embankment Dams 2004. EPA also reviewed MSHA's 2009 Engineering and 
Design Manual for Coal Refuse Disposal Facilities, in particular 
Chapter 7, ``Seismic Design: Stability and Deformation Analyses.'' 
These documents are viewed by ASDSO, FEMA and MSHA as generally 
accepted guidance on how to conduct seismic stability analyses. EPA 
chose the factor of safety of 1.00 because the 1.00 quantity represents 
the condition of the slope in which the strength of resistance to 
loading is equal to the anticipated loading stress acting upon the 
embankment, or the value which represents stability under the 
appropriate loading condition.
    The liquefaction factor of safety is adopted from review of several 
dam safety guidance and liquefaction guidance, including ``Soil 
Liquefaction During Earthquakes,'' Idriss and Boulanger, Earthquake 
Engineering Research Institute, 2008,\91\ ``Geotechnical and Stability 
Analyses for Ohio Waste Containment Facilities,'' Ohio EPA, Sept. 14, 
2004, Chapter 5,\92\ and Federal Guidelines for Dam Safety: Earthquake 
Analyses and Design of Dams, Document 65, FEMA May 2005.\93\ EPA also 
reviewed several technical resources regarding soil liquefaction, 
including ``Ground Motions and Soil Liquefaction During Earthquakes,'' 
Seed and Idriss, 1982,\94\ ``Liquefaction Resistance of Soils: Summary 
report from the 1996 and 1998 NCEER/NSF Workshops on Evaluation of 
Liquefaction Resistance of Soils,'' Youd and Idriss, 2001,\95\ and 
Seismic Design Guidance for Municipal Solid Waste Landfill Facilities, 
US EPA, Office of Research and Development, 1995. EPA chose a 
liquefaction factor of safety of 1.20, identifying that consideration 
of liquefaction potential and post-liquefaction residual strength slope 
stability included several uncertainties in assumptions and analysis 
which must be accounted for in a factor of safety above unity (i.e., 
1.00). FEMA guidance explicitly states that ``post-liquefaction factors 
of safety are generally required to be a minimum of 1.2 to 1.3.''
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    \91\ https://www.eeri.org/products-page/monographs/soil-liquefaction-during-earthquakes-3/.
    \92\ http://epa.ohio.gov/portals/34/document/guidance/gd_660.pdf.
    \93\ http://www.ferc.gov/industries/hydropower/safety/guidelines/fema-65.pdf.
    \94\ Seed, H.B., and Idriss, I.M., 1982, ``Ground Motions and 
Soil Liquefaction During Earthquakes,'' Monograph No. 5, Earthquake 
Engineering Research Institute, Berkeley, California, pp. 134.
    \95\ Youd, T.L., Idriss, I.M., 2001, ``Liquefaction Resistance 
of Soils: Summary report from the 1996 and 1998 NCEER/NSF Workshops 
on Evaluation of Liquefaction Resistance of Soils.'' Journal of 
Geotechnical and Geoenvironmental Engineering, ASCE.
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    In conjunction with this requirement, EPA continues to require 
periodic re-assessments of the safety factor calculations, but as 
discussed, has modified the frequency to be no less than once every 
five years for all affected CCR units. Periodic reassessments are 
necessary to account for factors that are subject to change and can 
adversely affect the structural stability of a CCR unit, e.g., age, 
use, volume of material contained within, and to reflect the dynamic 
nature of a CCR surface impoundment and the loads to which the dikes of 
the CCR surface impoundment may reasonably be expected to become 
subject to both the requirement to periodically reassess safety factor 
calculations and the five-year timeframes are consistent with the 
guidance set forth by other federal agencies in assessing dam safety, 
including MSHA, FEMA, and the USACE. For example, FEMA's Federal 
Guidelines for Dam Safety explicitly recommends that a dam be formally 
reassessed at an interval not to exceed every five years, and EPA has 
adopted this minimum frequency of assessment in this final rule.
(a) General Safety Factor Assessment Considerations
    Generally accepted engineering methodologies specify that the 
determination of the structural stability factors of safety specified 
above is to be calculated by the qualified professional engineer using 
conventional analysis procedures or, if necessary, special analysis 
procedures. Conventional analysis procedures include, but are not 
limited to, limit equilibrium methods of slope stability analysis, 
whereas, special analysis procedures include, but are not limited to, 
finite element methods, finite difference methods, three-dimensional 
methods, or probabilistic methods. Whichever methodology is used to 
determine the factors of safety of the CCR surface impoundment, the 
qualified professional engineer must document the methodology used, as 
well as the basis for using that methodology, and the analysis must be 
supported by appropriate engineering calculations.
    Limit equilibrium methods compare forces, moments, and stresses 
which cause instability of the mass of the embankment to those which 
resist that instability. The principle of the limit equilibrium method 
is to assume that if the slope under consideration were about to fail, 
or at the structural limit of failure, then one must determine the 
resulting shear stresses along the expected failure surface. These 
determined shear stresses are then compared with the shear strength of 
the soils along the expected failure surface to determine the factor of 
safety. Limit equilibrium methods include, but are not limited to, 
methods of slices. The most commonly applicable method of slices are 
the ordinary method of slices or Modified Swedish Method, Bishop's 
Modified Method, force equilibrium methods, Janbu's method, Morgenstern 
and Price's method, or Spencer's Method.
    If conventional analysis procedures yield results that indicate 
complex failure mechanisms or the need for estimation of displacements, 
such as the need to determine internal stresses or displacements in an 
embankment or account for 3-dimensional effects in an embankment, 
special analysis procedures may be necessary to calculate factors of 
safety. Special analysis procedures include, but are not limited to: 
(1) The finite element method; (2) the finite difference method; (3) 
the three-dimensional limit equilibrium analysis method; or (4) the 
probabilistic method.\96\
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    \96\ Additional information regarding special analysis 
methodologies can be found in publications from the U.S. Army Corps 
of Engineers Engineering Publications or geotechnical journals and 
scholarly articles.
---------------------------------------------------------------------------

    Structural stability factors of safety need to be met in all cross-
sections of the CCR surface impoundment since the failure of any cross-
section of the CCR surface impoundment can result in the loss of the 
reservoir and stored CCR material in the CCR surface impoundment. 
However, it is not necessary to require the facility to fully analyze 
and calculate factors of safety for all cross sections under the 
specific loading conditions identified above. Rather, it is sufficient 
to calculate the factors of safety under both static, seismic, and 
liquefaction loading conditions only for the critical cross section of 
the CCR surface impoundment embankment, provided the facility carefully 
analyzes each cross section to properly identify the critical cross 
section. EPA has adopted this approach because the critical cross-
section(s) represents a ``most-severe'' case and it is reasonably 
anticipated that all other cross-sections of the embankment will exceed 
the calculated factors of safety of the critical cross-section(s). The 
final rule therefore adopts this approach. The final rule

[[Page 21384]]

defines the critical cross section of the embankment of a CCR surface 
impoundment to be that which is anticipated to be most susceptible 
amongst all cross sections of the embankment to structural failure 
based on several engineering considerations for the given loading 
condition, such as soil composition of the cross-section, phreatic 
surface level within the cross section, grade of the upstream and 
downstream slopes of the cross section, and presence or lack of 
reinforcing measures in the cross-section as opposed to other cross-
sections, such as buttressing or slope protection on the slopes of the 
cross section. Due to the variance of qualitative and quantitative 
properties of embankment structural strength, EPA expects that a 
prudent engineering analysis will need to consider multiple cross 
sections to ensure proper selection of a critical cross section.
(b) The Calculated Static Factor of Safety Under the Long-Term, Maximum 
Storage Pool Loading Condition
    It is generally accepted practice to analyze the stability of the 
downstream slope of the dam embankment for steady-state seepage (or 
steady seepage) conditions with the reservoir at its normal operating 
pool elevation (usually the spillway crest elevation) since this is the 
loading condition the embankment will experience most. This condition 
is called steady seepage with maximum storage pool. The maximum storage 
pool loading is the maximum water level that can be maintained that 
will result in the full development of a steady-state seepage 
condition. Maximum storage pool loading conditions need to be 
calculated to ensure that the CCR surface impoundment can withstand a 
maximum expected pool elevation with full development of saturation in 
the embankment under long-term loading. The final rule requires that 
the calculated static factor of safety for the critical cross section 
of the CCR surface impoundment under the long-term maximum storage pool 
loading condition meet or exceed 1.5. The generally accepted 
methodology for determining the long-term, maximum storage pool loading 
condition considers conditions at the CCR surface impoundment that 
exist for a length of time sufficient for steady-state seepage or 
hydrostatic conditions to fully develop within the embankment of the 
CCR unit.\97\ The maximum storage pool loading needs to consider a pool 
elevation in the CCR unit that is equivalent to the lowest elevation of 
the invert of the spillway, i.e., the lowest overflow point of the 
perimeter of the embankment. The generally accepted methodology for the 
calculation of the factors of safety uses shear strengths expressed as 
effective stress and with pore water pressures that correspond to the 
long-term condition. Pore-water pressures should be estimated from the 
most reliable of the following sources: (1) Field measurements of pore 
pressures in existing slopes; (2) past experience and judgment of the 
qualified professional engineer; (3) hydrostatic pressure computation 
for conditions of no flow; or (4) steady-state seepage analysis using 
flow nets or finite element analyses.
---------------------------------------------------------------------------

    \97\ U.S. Army Corps of Engineers ``Slope Stability'' manual.
---------------------------------------------------------------------------

(c) The Calculated Static Factor of Safety Under the Maximum Surcharge 
Pool Loading Condition
    The maximum surcharge pool loading condition is calculated to 
evaluate the effect of a raised level (e.g., flood surcharge) on the 
stability of the downstream slope. This ensures that the CCR surface 
impoundment can withstand a temporary rise in pool elevation above the 
maximum storage pool elevation for which the CCR surface impoundment 
may normally be subject under inflow design flood stage, for a short-
term until the inflow design flood is passed through the CCR surface 
impoundment. The final rule requires that the calculated static factor 
of safety for the critical cross section of the CCR surface impoundment 
under the long-term maximum surcharge pool loading condition meet or 
exceed 1.4.
    Similar to the long-term, maximum loading condition, a prudent 
evaluation of the maximum surcharge pool loading condition needs to 
consider conditions at the CCR unit to exist for a length of time 
sufficient for steady-state seepage or hydrostatic conditions to fully 
develop within the embankment of the CCR surface impoundment. The 
maximum surcharge pool is considered a temporary pool that is higher 
than the maximum storage pool; the maximum surcharge loading condition 
should therefore consider a temporary condition in the pool at which 
the pool exists temporarily above the maximum storage pool elevation in 
the event of an inflow design flood and spillway discharge condition in 
the reservoir, i.e., above the lowest invert of the spillway during the 
anticipated inflow design flood.
(d) The Calculated Seismic Factor of Safety
    All CCR surface impoundments, including any lateral expansions that 
exceed the size threshold must meet a seismic factor of safety equal to 
or greater than 1.0. EPA has included this requirement because the 
mechanics and response phenomena of geotechnical structures vary 
radically under dynamic loading from those under static loading. 
Consequently, reliance on the factors of safety under static loading is 
not sufficient to evaluate the structural stability of a CCR surface 
impoundment. Standard engineering methodology and guidance support 
EPA's conclusion that adequate seismic analysis of embanked structures 
is essential to ensure the continued structural stability of a 
geotechnical structure under dynamic, or seismic, loading is 
warranted.\98\
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    \98\ E.g., FEMA's Federal Guidelines for Dam Safety: Earthquake 
Analyses and Design of Dams.
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    As discussed in the section of this preamble addressing the 
location criteria, all CCR surface impoundments must also be capable of 
withstanding a design earthquake without damage to the foundation or 
embankment that would cause a discharge of its contents. To further 
support the location criteria established in this rule, CCR surface 
impoundments and any lateral expansion exceeding a specific height and/
or volume threshold must be assessed under seismic loading conditions 
for a seismic loading event with a 2% probability of exceedance in 50 
years, equivalent to a return period of approximately 2,500 years, 
based on the USGS seismic hazard maps for seismic events with this 
return period for the region where the CCR unit is located. EPA chose 
the 2% exceedance probability in 50 years event based on its common use 
in seismic design criteria throughout engineering. See for example, 
ASCE 7 Minimum Design Loads for Buildings and Other Structures, 
International Building Code. Moreover, USGS seismic hazard maps, 
dictate that the life of a structure and the realistic probability of 
event occurrence be considered in the design of lateral force resisting 
systems for structures. As discussed in the Regulatory Impact 
Assessment, the expected life of a CCR surface impoundment can exceed 
50 years. Consistent with the location criteria for seismic impact 
zones, EPA adopted 2% as a reasonable probability of occurrence.
    Under standard engineering methodologies, seismic analysis includes 
several procedures to adequately analyze the structural

[[Page 21385]]

strength of a CCR surface impoundment during dynamic, i.e., seismic, 
loading. Such analyses would typically need to include the appropriate 
characterization of ground motions at the site of the CCR surface 
impoundment for the 2% probability in 50 years seismic event.\99\ In 
addition, the peak ground acceleration (PGA), velocity, and 
displacement should be selected using historic records, site-specific 
observations, or magnitude-distance attenuation relations. 
Additionally, the analysis would need to include an appropriate 
duration of earthquake, considering accelorograms for the anticipated 
event. Appropriate elastic response spectra should be selected using 
engineering methodology for selection, such as the Newmark-Hall 
Spectrum or other appropriate published spectra, USGS Probabilistic 
Maps, or site-specific response spectra.
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    \99\ FEMA Doc. 65 ``Earthquake Analyses and Design of Dams;'' 
http://www.ferc.gov/industries/hydropower/safety/guidelines/fema-65.pdf.
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(e) The Calculated Liquefaction Factor of Safety
    All CCR surface impoundments, including any lateral expansions that 
exceed the size threshold and have been determined to contain soils 
susceptible to liquefaction must meet a liquefaction factor of safety 
equal to or greater than 1.20. A prudent engineering analysis of 
structural stability also includes a liquefaction potential analysis 
and analysis of post-liquefaction static factors of safety. As 
discussed previously, liquefaction is a phenomenon which typically 
occurs in loose, saturated or partially-saturated soils in which the 
effective stress of the soils reduces to zero, corresponding to a total 
loss of shear strength of the soil. The most common occurrence of 
liquefaction is in loose soils, typically sands. The liquefaction FOS 
determination in the final rule is used to determine if a CCR unit 
would remain stable if the soils of the embankment of the CCR unit were 
to experience liquefaction. Liquefaction analysis is only necessary in 
instances where CCR surface impoundments show, through representative 
soil sampling, construction documentation, or anecdotal evidence from 
personnel with knowledge of the CCR unit's construction, that soils of 
the embankment are susceptible to liquefaction.
    EPA has included this requirement because the mechanics and 
response phenomena of geotechnical structures vary radically following 
induced liquefaction, i.e., post-liquefaction. Similar to the 
requirement for seismic factors of safety, liquefaction factors of 
safety are necessary because reliance on static loading is not 
sufficient to evaluate the structural stability of a CCR surface 
impoundment. Standard engineering methodology and guidance support 
EPA's conclusion that adequate liquefaction potential analyses and 
post-liquefaction residual strength slope stability analyses of 
embanked structures is essential to ensure the continued structural 
stability of a geotechnical structure following dynamic loading.
    Under standard engineering methodologies, liquefaction potential 
analysis and post-liquefaction stability analysis includes several 
procedures to adequately analyze the structural strength of a CCR 
surface impoundment. Because only certain soils, such as loose sands, 
are susceptible to liquefaction, the rule requires only embankments 
constructed of such soils identified through liquefaction potential 
analysis to meet liquefaction factors of safety. Such liquefaction 
potential analysis would need to include proper soil characterization 
of the embankment soils for soil age and origin, fines content and 
plasticity index, water content, saturation, and maximum current, past, 
and anticipated future phreatic surface levels within the embankment, 
foundation, or abutments, location beneath the natural ground surface, 
and penetration resistance whether through standard penetration testing 
(SPT) or, ideally, cone penetration testing (CPT). Post-liquefaction 
stability analysis would need to include detailed characterization of 
the site conditions, identification of the minimum liquefaction-
inducing forces based on soil characterization, determination of 
seismic effect on liquefied layers of the embankment, and calculation 
of factors of safety against each liquefied layer of the embankment.
(f) The Calculated Static Factor of Safety Under the End-of-
Construction Loading Condition
    The End-of-Construction loading condition must be calculated for 
new CCR surface impoundments to ensure that the CCR surface impoundment 
can withstand a ``first-filling'' of the embankment, during which time 
the embankment first become saturated and is subject to phreatic flow 
through the cross-section.
    Embankments are typically constructed in layers with soils at or 
above their optimum moisture content that undergo internal 
consolidation because of the weight of the overlying layers. Embankment 
layers may become saturated during construction as a result of 
consolidation of the layers or by rainfall. Because of the low 
permeability of fine-grained soils of which many embankments are 
constructed and the relatively short time for construction of the 
embankment, there can be little drainage of the water from the soil 
during construction: resulting in the development of significant pore 
pressures. Soils with above optimum moisture content will develop pore 
pressures more readily when compacted than soils with moisture contents 
below optimum. In general, the most severe construction loading 
condition is at the end of construction.
    The final rule requires that the calculated static factor of safety 
for the critical cross section of the CCR surface impoundment under end 
of construction loading conditions meet or exceed 1.30. The End-of-
Construction loading condition is analyzed for new construction under 
their initial filling condition, following the completion of 
construction. Undrained shear strength conditions are typically assumed 
for the End-of-Construction loading condition. Both the upstream and 
downstream slopes of the embankment are analyzed for this condition
(g) Failure To Demonstrate Minimum Safety Factors or Failure To 
Complete a Timely Safety Factor Assessment
    As previously discussed, the rule requires an owner or operator to 
document that the calculated factors of safety for each CCR surface 
impoundment achieve the minimum safety factors specified in the rule. 
For any CCR surface impoundment that does not meet these requirements, 
the owner or operator must either take any engineering measure 
necessary to ensure that the unit meets the requirements by the rule's 
deadlines, or cease placement of CCR and non-CCR waste into the unit 
and initiate closure of such CCR unit as provided in section 257.102 
within six months. Similarly, if an owner or operator fails to complete 
the initial safety factor assessment or any subsequent periodic factor 
safety assessment by the deadlines established in the rule, the owner 
or operator must cease placing CCR and non-CCR waste into the unit and 
initiate closure within six months.
(h) Vertical Expansions of CCR Surface Impoundments and Structural 
Integrity Criteria
    It is not uncommon for the owner or operator to raise the crest of 
a CCR surface impoundment to accommodate the additional capacity needs 
of the

[[Page 21386]]

facility. The record documents that CCR surface impoundments are 
commonly expanded from the original design or as-built construction, 
through such ``vertical expansions,'' including where a CCR surface 
impoundment changes from a ``small'' CCR unit (i.e., below the height 
and/or volume threshold) to a ``large'' CCR unit (i.e., exceeding the 
height and/or volume threshold). In these situations, the owner or 
operator of the CCR unit becomes subject to additional structural 
integrity requirements as a result of the vertical expansion. Realizing 
that these newly created CCR units will require some time to meet the 
structural integrity requirements, the Agency is allowing one year from 
the completion of the vertical expansion for the owner or operator to 
comply with the requirements of Sec. Sec.  257.73 or 257.74, as 
applicable.

F. Operating Criteria--Air Criteria

    EPA proposed to require CCR landfills, CCR surface impoundments and 
any lateral expansion to control the creation of fugitive dust. 
Specifically, EPA proposed that facilities must ensure that fugitive 
dust either not exceed the standard of 35 [mu]g/m\3\, established as 
the level of the 24-hour National Ambient Air Quality Standards (NAAQS) 
for fine particulate matter (PM-2.5), or any alternative standard 
established pursuant to applicable requirements developed under a State 
Implementation Plan (SIP) approved or promulgated by the Administrator 
pursuant to section 110 of the CAA (see 75 FR 55175). Consistent with 
the numerical standard, EPA proposed to require that CCR units be 
managed to control the wind dispersal of dust, and that CCR landfills 
also be required to emplace wet conditioned CCR (i.e., wetting CCR with 
water to a moisture-content that prevents wind dispersal and 
facilitates compaction, but does not result in free liquids) into the 
unit. EPA also required that documentation of the measures taken to 
comply with the requirements be certified by an independent registered 
professional engineer. EPA proposed these requirements based on the 
results of a screening level analysis of the risks posed by fugitive 
dust from CCR landfills, which showed that without fugitive dust 
controls, levels at nearby locations could exceed 35 [mu]g/m\3\, 
established as the level of the 24-hour PM 2.5 NAAQS for fine 
particulate. These measures were also intended to reduce the excessive 
cancer risks associated with the inhalation of hexavalent chromium. 
This potential risk would apply to over six million people who live 
within the census population data ``zip code tabulation areas'' for the 
495 rule-affected electric utility plant locations. (See 75 FR 35215.) 
\100\
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    \100\ As evidenced in 42 U.S.C. 6971(f), Congress intended that 
the Occupational Safety and Health Administration (OSHA) be able to 
enforce its regulations to protect workers exposed to hazardous 
waste and that EPA and OSHA would work together to ensure that. EPA 
is clarifying that it intends that the CCR disposal rule not preempt 
applicable OSHA standards designed to protect workers exposed to 
CCRs; thus EPA's final rule on CCR disposal will apply in addition 
to any applicable OSHA standards. The Agency has added specific 
regulatory language in this section to address this intent.
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    As part of the proposal, EPA solicited comments on the following 
fugitive dust issues: (1) The location of air monitoring stations near 
CCR landfills or CCR surface impoundments; and (2) information on any 
techniques, such as wetting, compaction, or daily cover that are or can 
be employed to reduce exposures to fugitive dust. The Agency received 
no information from commenters on either of these issues.
    The majority of comments received, however, took issue with the 
proposed technical standard of 35 ug/m\3\. Commenters argued that, as 
proposed, the standard would be impossible to implement because the 
Agency provided no information on particle size, form of the standards, 
whether an averaging period is available, point of compliance or how 
one considers upwind sources. More generally, however, commenters 
argued that the proposed provisions were unnecessary because fugitive 
dust issues were adequately addressed by existing air rules through the 
development and implementation of NAAQS, such as PM10 and 
PM2.5. These same commenters acknowledged, however, that if 
the Agency established a criterion to control fugitive dusts, a more 
appropriate and reasonable standard could be based on best management 
practices or BMPs. To that end, commenters offered information 
suggesting that CCR landfills typically used compaction, regular 
wetting and temporary covers in conjunction with visual air monitoring 
to effectively control fugitive dust at their facilities, and that 
these practices were included in facility operating plans.
    As discussed in the proposed rule, EPA's decision to address 
fugitive dust was based on a peer review of the 2010 draft Risk 
Assessment, 2007 NODA stakeholder comments, photographic documentation 
of fugitive dust associated with the management of CCR, Agency actions 
to control fugitive emissions during the clean-up of the December 2008 
TVA Kingston spill, and OSHA's Material Safety Data Sheets (now Safety 
Data Sheets (SDS)) requirements for coal ash. These lines of evidence 
have been bolstered since the proposal, by evidence collected during 
the eight 2010 CCR public hearings, where stakeholders provided 
extensive feedback about fugitive dust impacts associated with CCR 
management at facilities adjacent to their residences, and by 
documented reports on fugitive dust issues provided by citizen 
groups.\101\ The stakeholders called for federal oversight to address 
those instances where complaints were seemingly ignored by state 
regulators and/or where state administrative enforcement measures 
failed to compel the utilities to effectively amend their dust emission 
control management practices. The Agency followed up on the complaints 
with state agencies and compiled a preliminary database on documented 
and alleged fugitive dust damage cases.\102\
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    \101\ For instance, photographic evidence provided by Susan 
Holmes, the Bokoshe Environmental Cause Group (B.E. Cause), Bokoshe, 
Oklahoma. See Earthjustice's brief background coverage at: http://earthjustice.org/blog/2011-april/not-having-fun-in-bokoshe-ok, and 
ABC News' Oklahoma Town Fears Cancer, Asthma May Be Linked to Dump 
Site, March 29, 2011: http://abcnews.go.com/US/oklahoma-town-fears-cancer-asthma-linked-dump-site/story?id=13240312.
    \102\ A compilation of damage cases can be found in the docket 
supporting this rule.
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    In support of this rule, EPA compiled records of over 20 documented 
fugitive dust cases, in addition to several alleged cases that could 
not be verified. The documented cases indicate that fugitive dust 
concerns arise in all phases of the CCR life cycle--from conveyor belt 
transfer at the coal-fired power plant, through stockpiling and 
transport for disposal/beneficial use, and up to final disposition. 
Fugitive dust also is a potential concern associated with both--
landfills and surface impoundments. Whereas a nexus between fugitive 
dust impacts and CCR landfill operations was to be expected, EPA 
discovered that fugitive dust was also of concern at CCR surface 
impoundments, either under conditions of windy winter spells affecting 
CCR exposed above or next to the CCR surface impoundment boundary, or 
due to the total CCR surface impoundment evaporation in arid areas.
    Very few studies have been undertaken to test the health impacts 
caused by fugitive dust emissions, and of those few, due to inherent 
limitations, all failed to prove that fugitive dust was the cause of 
the documented health concerns. For example, in the wake of the January

[[Page 21387]]

2005 coal ash pile collapse at the Rostosky Ridge Road, in Allegheny 
County, Pennsylvania, both the federal and county studies \103\ failed 
to test during this period and missed the narrow exposure window that 
would have possibly demonstrated a link between the event and the 
short-term health symptoms (e.g., sore throat, cough, fever, nausea, 
fatigue, diarrhea, and headaches) contracted by residents who 
ultimately removed approximately 1,500 tons of fly ash from their 
properties immediately after the incident without the benefit of any 
protective respiratory gear. The federal and county studies also found 
no evidence of long-term arsenic poisoning of the tested individuals. 
For recurring instances of CCR dispersion in the air at the Indian 
River Power Plant, Millsboro, Delaware, three consecutive state studies 
tentatively established other risk factors as the probable cause for a 
lung cancer cluster in a down-wind location of the presumable source 
term (CCR fugitive dust blowing of a landfill and stack 
emissions).\104\ Critics claim that these studies used too small of a 
sample, and were not designed to capture the impact of long-term 
exposure to pollution.\105\
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    \103\ (i) Coal Fly Ash Landslide, Forward Township, Allegheny 
County, Pennsylvania, ASTDR Health Consultation June 1, 2006: http://www.atsdr.cdc.gov/HAC/pha/CoalFlyAshLandslide/CoalFlyAshLandslideHC060106.pdf (ii) Results of the Health 
Investigation Following Fly Ash Contamination in Forward Township, 
Allegheny County, Pennsylvania, Allegheny County Health Department, 
July 2005: http://www.achd.net/air/pubs/pdf/Forward%20Fly%20Ash%20Study%202005.pdf.
    \104\ Millsboro Inhalation Exposure and Biomonitoring Study. 
State of Delaware Department of Natural Resources and Environmental 
Control, Department of Health and Social Services, Dover (RTI 
Project 0213061), DE, May 2013: http://www.dnrec.delaware.gov/Admin/Documents/Millsboro_Inhalation_Exposure_and_Biomonitoring_Study_Final_Repor_05282013.pdf.
    \105\ Critic chides cancer study: Indian River plant results 
called lame. Delawareonline, May 28, 2013: http://www.delawareonline.com/article/20130528/NEWS/305280081/.
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    Nevertheless, in eleven other cases, states adopted measures to 
address concerns from fugitive dust emissions; these included 
conducting lung-cancer cluster and other health studies, conducting 
particle dispersion studies, issuing Notices of Violation and Consent 
Orders to the responsible facilities, waiving landfill cover 
exemptions, and requiring dust management plans for newly permitted CCR 
landfills. In addition, in several instances, citizens filed lawsuits 
or reached an out-of-court settlement with the primary responsible 
party; and in one case, OSHA imposed a steep fine on the owners of a 
facility manufacturing abrasive blasting and roofing materials from 
slag produced at a nearby coal-fired power plant, for willfully 
exposing their workers to dangerously high levels of hazardous dust, 
and for failing to provide adequate breathing protection and training 
for workers at the facility. According to stakeholder allegations, 
fugitive dusts generated by these same materials also adversely 
impacted residents in the facility's immediate vicinity.
    As previously stated, many commenters argued that the proposed 
numeric particulates standard was incompatible with the air quality 
requirements established under the States' Implementation Plans (SIPs) 
or with provisions set up by the states in their Title V Clean Air 
Permits to the power producers. In addition, the commenters argued that 
the proposed standard lacked technical details to facilitate effective 
implementation, and that implementation of the standard required 
specialized equipment and advanced training to carry out a judicious 
reading and interpretation of opacity, a proxy measure for the level of 
fugitive dust emissions. In light of these comments, EPA re-evaluated 
the existing CAA standards applicable to these units; 40 CFR 70.2 
identifies fossil-fuel-fired steam electric plants of more than 250 
million BTU/hour heat input as potential sources of fugitive dust (PM 
sources) that must be covered by state permitting, and 40 CFR 70.3 
stipulates that fugitive emissions from a part 70 source shall be 
included in the permit application and the part 70 permit in the same 
manner as stack emissions, regardless of whether the source category is 
included in the list of sources contained in the definition of major 
source. Based on these applicable CAA requirements, the Agency agrees 
that the adoption of a PM standard under the final rule would entail a 
potential for duplication or inconsistency with applicable state-
established standards in SIP permits.
    EPA also acknowledges the challenges involved in measuring the 
proposed compliance standard. Because fugitive dust is emitted from 
non-point sources, it cannot be easily measured by conventional 
methods. Usually, regulations developed by the states to control 
fugitive dust stipulate that no person or source shall cause or allow, 
from any activity, any emissions of fugitive particulate matter that 
are visible to an observer who looks horizontally along the source's 
property line. A quantitative measurement of fugitive dust levels 
(EPA's Reference Method 9) would require measuring opacity, which, as 
the commenters noted, necessitates specialized technical training, 
trainee certification, and judicious application of instrumentation.
    Therefore, rather than requiring a potentially redundant and 
challenging-to-implement quantitative standard, EPA is substituting a 
performance standard for fugitive dust control. This standard requires 
owners or operators of a CCR unit to adopt measures that will 
effectively minimize CCR from becoming airborne at the facility, 
including CCR fugitive dust originating from CCR units, CCR piles, 
roads, and other CCR management activities. The Agency considers this 
standard to be consistent with the intent of the proposed rule, with 
the added advantage of allowing facilities the flexibility to determine 
the appropriate measures to achieve regulatory compliance at their 
individual site. This standard and the accompanying regulatory 
requirements supporting its implementation, will achieve the statutory 
obligation of ``no reasonable probability of adverse effects on human 
health and the environment.''
    As in the proposal, the Agency is also requiring documentation of 
the measures taken to comply with the technical standard in a ``CCR 
fugitive dust control plan'' (herein referred to as ``plan''). 
Consistent with the proposal, the plan must be certified by a qualified 
professional engineer and placed in the operating record and on the 
owner or operators publicly accessible internet site. The plan requires 
owners or operators to elaborate on the types of activities applicable 
and appropriate for the conditions at the facility that will be 
employed to minimize CCR from becoming airborne at the facility. 
Examples of control measures that may be appropriate include: Locating 
CCR inside an enclosure or partial enclosure; operating a water spray 
or fogging system; reducing fall distances at material drop points; 
using wind barriers, compaction, or vegetative covers; establishing and 
enforcing reduced vehicle speed limits; paving and sweeping roads; 
covering trucks transporting CCR; reducing or halting operations during 
high wind events; or applying a daily cover.
    The initial plan must be completed by the effective date of the 
rule (i.e., within six months of publication). Because this is an 
initial plan, and because it must be completed within a short 
timeframe, EPA acknowledges that the facility may only be able to 
present its initial judgment of the measures that it anticipates are 
likely to be effective based on the information that is readily 
available within this six month

[[Page 21388]]

timeframe. EPA anticipates that owners or operators may need to revise 
the plan as they gain additional information and experience 
implementing the regulations. In recognition of this, the final rule 
also requires that the CCR fugitive dust control plan include a 
description of the procedures the owner or operator will follow to 
periodically assess the effectiveness of the control plan. Consistent 
with other plans required in this rule, the owner or operator may amend 
the written CCR fugitive dust control plan at any time. However, the 
owner or operator must amend the written plan whenever there is a 
change in conditions that would substantially affect the written plan 
in effect, such as the construction and operation of a new CCR unit. 
The plan and any subsequent amendments must be certified by a qualified 
professional engineer.
    In addition, the Agency is promulgating with a slight modification 
the requirement for owners and operators of all CCR landfills and any 
lateral expansion to emplace CCR as conditioned CCR, as well as the 
definition of conditioned CCR. Conditioned CCR has been defined to mean 
CCR wetted with water to a moisture content that will prevent wind 
dispersal, but will not result in free liquids, consistent with the 
definition in the proposed rule. In response to several commenters' 
requests, and upon further evaluation the Agency is allowing that in 
lieu of water, CCR conditioning may be accomplished with an appropriate 
chemical dust suppression agent.\106\ As with other requirements of 
this rule, in order to ensure that the provisions of the fugitive dust 
criteria are maintained throughout the operating life of the CCR unit, 
the Agency is requiring that the owner or operator prepare an annual 
CCR fugitive dust control report, describing the actions taken to 
control CCR fugitive dust, a record of all citizen complaints, and a 
summary of any corrective measures taken. The first annual report must 
be completed no later than 14 months after placing the initial CCR 
fugitive dust control plan in the facility's operating record. The 
owner or operator has completed the annual CCR fugitive dust control 
report when the plan has been placed in the facility's operating 
record.
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    \106\ Spray-on adhesives, surfactants, aqueous foamers, 
humectants (calcium, magnesium, ad sodium chloride and their 
mixtures), and polymer solutions and emulsions. See, for instance 
``The Role of Chemicals in Controlling Coal Dust Emissions'' 
Benetech, Inc. available at http://pdf.ebooks6.com/download.php?id=139860 or Peterson, Edwin. ``An Aid to Fugitive 
Materials Control in Coal Ash Applications'' presented at the World 
of Coal Ash (WOCA) conference--May 9-12, 2011 in Denver, Colorado.
---------------------------------------------------------------------------

    The general public, as well as the Agency, is highly concerned with 
potential risks associated with CCR fugitive dusts. This was readily 
apparent during the public hearings and from the many comments received 
on this issue. The Agency continues to receive information regarding 
this human health and environmental concern. While the subtitle D 
provisions of this rule lack permitting oversight mechanisms to control 
fugitive dust from CCR units, it is clear to the Agency that additional 
substantive actions was needed to facilitate citizen suit enforcement 
of this criteria. Consequently, the Agency are adding a specific 
requirement to the CCR fugitive dust control plan to require owners and 
operators of all CCR units to develop and implement formal procedures 
to log citizen complaints involving CCR fugitive dust events. These 
complaints must, then, be included as part of the annual CCR fugitive 
dust control report. This report must be placed in the operating record 
and on the owner or operator's publicly accessible internet site. 
Promulgation of these measures will subject the owner or operator of 
the CCR disposal facility to public and state scrutiny, and create an 
incentive for the owner or operator of the CCR disposal facility to 
improve compliance with the fugitive dust control requirements.

G. Operating Criteria--Run-On and Run-Off Controls for CCR Landfills

    EPA's proposal required owners or operators of CCR landfills and 
all lateral expansions to design, construct and maintain a run-on 
control system to prevent flow onto the active portion of these units 
during the peak discharge from a 24-hour, 25-year storm. As described 
in the proposed rule, run-on controls are designed to prevent erosion, 
which may damage the physical structure of the landfill, prevent the 
surface discharge of CCR in solution or suspension; and to minimize the 
downward percolation of run-on through wastes, creating leachate. 
Similarly, EPA proposed run-off controls in order to collect and 
control, at a minimum, the water volume resulting from a 24-hour, 25-
year storm. This standard was proposed in order to protect surface 
waters from contamination. Under the existing 40 CFR part 257 
requirements, to which CCR units are currently subject, run-off 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. EPA did not 
propose to revise the existing requirement, but merely incorporated it 
for ease of the regulated community.
    The Agency proposed the 24-hour period because it was a timeframe 
that included storms of high intensity with short duration and storms 
of low intensity with long duration. EPA believed that this was a 
widely used standard that had been incorporated into the hazardous 
waste landfills and MSW landfills regulatory requirements. At the time, 
EPA had no information that warranted a more restrictive standard for 
CCR landfills. EPA received no significant comment on the proposed 
requirements, and for the most part, is adopting the proposed 
requirements without revision. However, in an effort to clarify and 
provide more direction to the owner or operator and the certifying 
qualified professional engineer, the Agency has added additional 
regulatory language that more specifically describes the technical 
criteria established under this section of the rule.
    The run-on and run-off controls of the final rule require that the 
owner or operator prepare the initial run-on and run-off control system 
plan within 18 months of publication of the rule. Run-on and run-off 
control system plan reporting may require design, construction, and 
post-construction implementation. In instances where run-on and run-off 
capacity is insufficient, installing additional capacity may involve 
construction of diversion structures such as swales or ditches. Many of 
these efforts may require several months of design and construction, 
compounded by the fact that much of the work cannot be completed in 
cold-weather or heavy-rain seasons.
1. Run-On and Run-Off Controls for CCR Landfills and All Lateral 
Expansions \107\
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    \107\ In the proposed rule under the RCRA subtitle D option, EPA 
jointly proposed run-on and run-off requirements for CCR landfills 
and CCR surface impoundments under proposed Sec.  257.81. In this 
final rule, EPA has modified the ``run-on and run-off'' requirements 
and is providing separate requirements for CCR landfills and CCR 
surface impoundments. CCR surface impoundments are now subject to 
the hydrologic and hydraulic capacity requirements at Sec.  257.82. 
This new section of the rule more appropriately addresses flow 
management issues at CCR surface impoundments.
---------------------------------------------------------------------------

    All CCR landfills and all lateral expansions must be designed, 
constructed, operated, and maintained with a run-on control system to 
prevent flow onto the active portion of the CCR unit from the peak 
discharge from a 24-hour, 25-year storm and a run-off control system to 
collect and control at

[[Page 21389]]

least the volume of water resulting from a 24-hour, 25-year storm from 
the active portion of the CCR unit.\108\
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    \108\ Under 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 did not 
propose to revise this requirement but is merely incorporating it 
here for ease of the regulated community.
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    Consistent with the proposal, the rule requires the owner or 
operator of a CCR landfill or lateral expansion to prepare an initial 
run-on and run-off control system plan for the CCR unit. For existing 
CCR landfills, the plan must be prepared by the owner or operator no 
later than one year from the effective date of the rule. For new CCR 
landfills and any lateral expansion of a CCR landfill, the plan must be 
prepared no later than the date of initial placement of CCR in the 
landfill or lateral expansion. The plan must document how the run-on 
and run-off control systems have been designed and constructed to meet 
the requirements of rule and must be supported by appropriate 
engineering calculations. The run-on and run-off control system plan 
must be certified by a qualified professional engineer and is 
considered prepared when the owner or operator has placed the plan in 
the facility's operating record.
    The rule also provides for the owner or operator to amend the plan 
at any time (e.g., prior to receipt of CCR in the CCR unit, during the 
operating life of the CCR unit, during closure of the CCR unit, or 
following closure of the CCR unit) provided the revised plan is placed 
in the facility's operating record. The owner or operator must, however 
revise the plan whenever there is a change in the conditions that would 
substantially affect the written plan in effect (e.g., closure of an 
existing portion or cell of the CCR landfill, resulting in a possible 
change in the size of the ``active portion'' of the CCR landfill).
    In addition, consistent with other provisions in this rule, the 
Agency is requiring that the run-on and run-off control system plan be 
reviewed, and where necessary, revised or updated at least every five 
years. The Agency is specifying this periodic review in order to 
address factors having the potential to influence the run-on and run-
off control system. Among other things, CCR landfills can be subject to 
build-out, operational changes, and surface cover changes, all of which 
have the potential to significantly alter run-on and run-off flows to 
and from the active portion of the CCR landfill. Changes in storm 
intensity and duration, as well as upstream catchment area 
characteristics, can alter flows that may significantly affect a 
previously adequate run-on and run-off control system. A mandated five 
year review of a control system plan is consistent with accepted good 
engineering practices and protocols for proper maintenance of 
operational systems supporting the overall performance of a CCR 
landfill. It is also consistent with the proposed requirement that an 
owner or operator ``maintain'' the run-on and run-off control system. 
EPA interprets this to require the owner or operator to ensure that the 
run-on and run-off control system is kept in a condition that meets the 
requirements of the rule, i.e., that the run-on and run-off control 
system both prevents flow onto the active portion of the unit during 
the peak discharge from a 24-hour, 25-year storm and collects and 
controls at least the water volume resulting from a 24-hour, 25-year 
storm event for the duration of the CCR landfill's operational life. A 
requirement to conduct a review of the control plan at least once every 
five years merely provides an explicit mechanism to ensure this occurs 
in a manner that facilitates citizen and state oversight.
    The date of preparing the initial plan is the basis for 
establishing the deadline to complete the first subsequent plan; i.e., 
the subsequent plan must be completed within five years of the prior 
plan. The owner or operator may complete any required plan prior to the 
required deadline and must place the completed plan into the facility's 
operating record within the five year timeframe. A qualified 
professional engineer must certify that the run-on and run-off control 
system plan, including any subsequent amendments, meets the run-on and 
run-off control system requirements of this final rule.
a. Run-On Control
    Consistent with the proposal, EPA is defining run-on to mean any 
liquid that drains over land onto any part of a CCR landfill or any 
lateral expansion of a CCR landfill. In surface water hydrology, run-on 
is a quantity of surface run-off, or excess rain, snowmelt, or other 
sources of water, which flows from an upstream catchment area onto a 
specific downstream location. This rule requires that the CCR landfill 
be designed, constructed, operated, and maintained to prevent flow onto 
the active portion of the CCR landfill during the peak discharge from a 
24-hour, 25-year storm. EPA has adopted this requirement to minimize 
the amount of surface water entering the CCR landfill and to minimize 
disruption of the CCR landfills operation due to storm water inflow. 
Uncontrolled or undesirable storm water run-on may have significant 
impacts on the stability of the slopes of a CCR landfill and continued 
safe operation of the CCR landfill, due to such phenomena as erosion 
and infiltration.
b. Run-Off Control
    EPA has adopted the definition of run-off from the proposal without 
revision. Run-off means any liquid that drains over land from any part 
of the CCR landfill. Effectively, run-off is the portion of rainwater, 
snowmelt, or other liquid which does not undergo abstraction, such as 
infiltration, and travels overland. Typically, run-off is the product 
of the inability of water to infiltrate into soil due to saturation or 
infiltration rate capacity being exceeded. The rule requires that the 
CCR landfill be designed, constructed, operated, and maintained to 
collect and control at least the water volume resulting from a 24-hour, 
25-year storm. The owner or operator must design, construct, operate, 
and maintain the CCR landfill in such a way that any run-off generated 
from at least a 24-hour, 25-year storm must be collected through 
hydraulic structures, such as drainage ditches, toe drains, swales, or 
other means, and controlled so as to not adversely affect the condition 
of the CCR landfill. EPA has promulgated these requirements to minimize 
the detention time of run-off on the CCR landfill and minimize 
infiltration into the CCR landfill, to dissipate storm water run-off 
velocity, and to minimize erosion of CCR landfill slopes. An additional 
concern with run-off from CCR landfills is the water quality of the 
run-off, which may collect suspended solids from the landfill slopes. 
EPA acknowledges that the run-off requirements will also minimize the 
amount of run-off related pollution generated by the landfill run-off.
c. Run-On and Run-Off Control System Plan
    The owner or operator of any CCR landfill must prepare an initial 
run-on and run-off control system plan documenting, with supporting 
engineering calculations, how the control systems have been designed 
and constructed to meet the requirements of the rule. This has been 
adopted without revision from the proposal. In most cases, EPA expects 
this documentation will include in addition to the supporting 
engineering calculations, references and drawings regarding the

[[Page 21390]]

identification of the 24-hour, 25-year storm for the location of the 
CCR landfill, a characterization of the rainfall abstractions, 
including but not limited to depression storage and infiltration, the 
selection and basis of an appropriate run-off model, the selection and 
basis of an appropriate run-on or run-off routing model, and the 
selection and design of an appropriate run-on and run-off management 
system (e.g., swales, ditches, retention or detention ponds). 
Consideration of the above factors would generally constitute a 
comprehensive review of the hydraulic and hydrologic processes 
associated with the design of a run-on and run-off control system plan. 
EPA recognizes that over time, any number of factors, e.g., expansion 
of the facility, could affect a change in the run-on and run-off 
control system plan. Consequently in the final rule EPA is providing 
for flexibility in this area by stating that the plan can be amended by 
the owner or operator at any time during the life of the CCR landfill, 
provided the amendments are placed in the operating record and on the 
facility's publicly accessible Internet site.

H. Operating Criteria--Hydrologic and Hydraulic Capacity Requirements 
for CCR Surface Impoundments

    As discussed in the previous section, EPA proposed to require 
owners or operators of CCR landfills to design, construct, operate, and 
maintain: (1) A run-on control system to prevent flow onto the active 
portion of the unit during the peak discharge from a 24-hour, 25-year 
storm; and (2) a run-off control system to collect and control, at a 
minimum, the water volume resulting from the same 24-hour, 25-year 
storm. EPA also proposed to apply these same run-on and run-off 
requirements to all CCR surface impoundments and lateral expansions.
    Commenters overwhelmingly disagreed with EPA's decision to apply 
the same run-on and run-off requirements to both CCR landfills and CCR 
surface impoundments, arguing that a ``control system to prevent flow 
onto the active portion of the surface impoundment'' was at odds with a 
commonly employed practice of using CCR surface impoundments to manage 
incoming storm water and other inflow. While some commenters reasoned 
that preventing run-on may be appropriate for CCR landfills and CCR 
surface impoundments surrounded by above-ground dikes, the proposed 
requirement was entirely inappropriate for units specifically designed 
to retain storm water from an adjoining watershed or to operate as part 
of a facility's overall storm water management system. Numerous 
commenters suggested that instead of the run-on prevention provision 
for CCR surface impoundments, EPA adopt a requirement specifying that 
CCR surface impoundments be designed to accommodate ``peak discharge 
events.'' Other commenters argued that storm water run-on controls were 
only appropriate during and after the closure of CCR surface 
impoundments; while still other commenters suggested that EPA remove 
entirely the run-on and run-off requirements because CCR surface 
impoundments were typically designed to impound and discharge storm 
water flow far in excess of a 25-year/24-hour storm event.
    In evaluating the arguments against the requirements to prevent 
flow onto the CCR surface impoundment, the Agency was strongly 
influenced by guidance developed by FEMA for selecting and 
accommodating hydraulic and hydrologic inflow and outflow as well as 
the application of this guidance to the CCR surface impoundments 
evaluated as part of EPA's Assessment Program.\109\ A review of FEMA 
guidance confirmed commenters' contentions that managing flow both to 
and from dams and impoundments was a widely used practice, and a 
preferable management strategy for accommodating storm water flows. 
This was further confirmed by observations made during EPA's Assessment 
Program; EPA frequently observed units designed to detain or retain 
storm water inflows of an upstream catchment area to manage CCR, and/or 
to receive storm water inflow as part of the facility's overall storm 
water management system. Moreover, EPA relied on the same FEMA guidance 
to assess the adequacy of the hydrologic and hydraulic capacity of the 
CCR surface impoundments. In conducting these assessments, EPA 
considered a number of factors including operating freeboard, catchment 
area, hydrologic structures' inflow and outflow ratings, design 
precipitation event, spillway presence and capacity, and unit operating 
procedures to make this determination. The adequacy of the capacity was 
determined using FEMA guidance for selecting and accommodating inflow 
design floods (IDF) for dams. (Note: The use of the terminology related 
to ``inflow design flood'' for CCR surface impoundments rather than 
``run-on'' and ``run-off'' is more directly applicable to the hydraulic 
and hydrologic capacity of CCR surface impoundments to adequately 
manage both the inflow and outflow from a design flood.)
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    \109\ EPA referred to FEMA's ``Federal Guidelines for Dam 
Safety: Selecting and Accommodating Inflow Design Floods for Dams'' 
in evaluating the adequacy of the CCR surface impoundment's 
hydrologic and hydraulic capacity during its assessment effort.
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    During its assessment effort, EPA also found that, contrary to 
commenter's arguments CCR surface impoundments were often not designed 
to address floods in excess of a 24-hour, 25-year storm event. Rather 
many CCR surface impoundments were deficient in their hydrologic and 
hydraulic capacity requirements due to factors such as lack of 
operating freeboard, misunderstanding of the actual contributory area, 
lack of documentation, undersized decant structures, undersized 
spillways, and lack of spillways.
    EPA also disagrees with the comment asserting that storm water 
controls are only appropriate during and after closure of CCR surface 
impoundments. Hydrologic and hydraulic capacity, as determined by an 
effective design flood control system, is an essential element of the 
overall structural integrity and safety of a CCR surface impoundment. 
CCR surface impoundments are subject to any number of stresses 
throughout their operational life; one of the most common causes of a 
dike or embankment failure being the inability of the CCR unit to 
adequately pass or manage flood flows resultant from direct or indirect 
precipitation. These failures can occur at any point in the CCR unit's 
life, not solely during and after closure, and are usually due to 
inadequate hydrologic and hydraulic capacity, leading to internal 
erosion due to seepage and piping, erosion of spillways, overtopping 
erosion, and overstressing of the embankment. Furthermore, according to 
the U.S. Bureau of Reclamation, a common dam failure mode is due to 
overtopping, accounting for 30% of the failures in the U.S. over the 
last 75 years.\110\ Overtopping is the direct result of lack of 
adequate hydrologic and hydraulic capacity of a dam or surface 
impoundment. Therefore, EPA is not modifying the regulation as 
suggested by the commenter.
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    \110\ http://www.usbr.gov/ssle/damsafety/Risk/BestPractices/16-FloodOvertoppingPP20121126.pdf.
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    In light of comments received, observations made during EPA's 
Assessment Program, and guidance developed by FEMA, EPA has concluded 
that it was inappropriate to propose to prohibit all run-on discharge 
or inflow from storm water to CCR surface impoundments. EPA has also

[[Page 21391]]

concluded that run-on and run-off criteria are inappropriate for CCR 
surface impoundments, and that a more appropriate standard involves 
determining the hydrologic and hydraulic capacity of a unit, measured 
by its inflow design flood or IDF. Therefore, EPA is amending the 
proposed run-on and run-off requirements for CCR surface impoundments 
to require owners or operators of all CCR surface impoundments to 
design, construct, operate, and maintain hydraulic and hydrologic 
capacity to adequately manage flow both into and from a CCR surface 
impoundment during and after the peak discharge resulting from the 
inflow design flood, based on the Hazard Potential Classification of 
the CCR surface impoundment.
    The final rule requires the preparation of the initial inflow 
design flood control system plan within 18 months of publication of the 
final rule. In many cases, inflow design flood control system plan 
reporting may require design, construction, and post-construction 
implementation in order to provide sufficient hydrologic and hydraulic 
(H/H) capacity for the CCR unit. In instances where H/H capacity is 
insufficient, installing additional capacity may involve spillway 
construction or decant structure construction or installation. Many of 
these efforts may require several months of design and construction, 
compounded by the fact that much of the work cannot be completed in 
cold-weather or heavy-rain seasons.
1. Inflow Design Flood Controls for CCR Surface Impoundments and All 
Expansions
    The Agency has concluded that the proposed requirement preventing 
run-on to a CCR surface impoundment was both impractical and 
unwarranted and could possibly disrupt effective storm water management 
systems operating at CCR facilities. Therefore, consistent with FEMA 
guidance, the Agency is modifying this requirement to require an owner 
or operator of an existing or new CCR surface impoundment or any 
lateral expansion to design, construct, operate, and maintain H/H 
capacity of CCR surface impoundments to: (1) Adequately manage flow 
into the CCR surface impoundment during and following the peak 
discharge of the inflow design flood; and (2) adequately manage flow 
from the CCR unit to collect and control the peak discharge resulting 
from the inflow design flood. The inflow design flood is based on the 
hazard potential classification of the unit as required by Sec.  257.73 
and Sec.  257.74 of this rule.\111\ The inflow design floods for 
specific hazard potential classifications are as follows: (1) The 
probable maximum flood (PMF) for high hazard potential CCR surface 
impoundments; (2) the 1000-year flood for significant hazard potential 
CCR surface impoundments; (3) the 100-year flood for low hazard 
potential CCR surface impoundments; and (4) the 25-year flood for 
incised CCR surface impoundments.\112\
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    \111\ Federal Guidelines for Dam Safety: Selecting and 
Accommodating Inflow Design Floods for Dams. August 1, 2013. FEMA P-
94.
    \112\ All discharge from the CCR surface impoundment must be 
handled in accordance with the surface water requirements under 
Sec.  257.3-3.
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    EPA has based this revised requirement on the FEMA's guidance 
entitled, ``Selecting and Accommodating Inflow Design Floods for 
Dams,'' which represents current and accepted practices in dam 
engineering and provides a consistent and uniform standard that has 
been adopted throughout dam engineering.
    Incised CCR surface impoundments, as defined in this rule, are also 
required to meet inflow design flood requirements.\113\ While incised 
units do not pose the same potential for release as a diked unit, i.e., 
breach of dike and release of CCR, overtopping of an incised unit does 
represent a potential environmental hazard warranting control. EPA 
acknowledges, however, that overtopping of an incised unit would result 
in a release of CCR material through a surcharge flow, i.e., flow of a 
temporary stage overtopping the ``crest'' of the incised CCR surface 
impoundment, and would not precipitate the degradation of a dike and 
potential subsequent breach of a dike and massive release of contents 
of the CCR surface impoundment. To reflect the lower risks associated 
with such releases, and because incised CCR surface impoundments are 
not required to determine their hazard potential classification, the 
Agency is requiring that incised CCR surface impoundments only must 
accommodate a 25-year flood for the hydrologic and hydraulic capacity 
requirements of the rule. EPA chose the 25-year flood for incised CCR 
surface impoundments to maintain consistency with the proposed rule, 
which required that all units accommodate a 25-year storm event. As 
part of these requirements, EPA is also finalizing a definition of 
inflow design flood and flood hydrograph. Inflow design flood has been 
defined to mean the flood hydrograph that is used to design or modify 
the CCR surface impoundment and its appurtenant works, and flood 
hydrograph has been defined to mean the temporal distribution of inflow 
into a CCR surface impoundment.
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    \113\ Incised CCR surface impoundment means a CCR surface 
impoundment which is constructed by excavating entirely below the 
natural ground surface, holds an accumulation of CCR entirely below 
the adjacent natural ground surface, and does not consist of any 
constructed diked portion.
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2. Inflow Design Flood Control Systems
    Controlling the inflow and outflow of the CCR surface impoundment 
reduces the risks of hydrologic failure, which include overtopping 
erosion, internal excessive seepage and piping, erosion of spillways, 
and overstressing of the structural components of the CCR surface 
impoundment. The CCR surface impoundment's H/H capacity is to be 
designed based on the unit's hazard potential classification as 
determined by a qualified professional engineer. To meet the 
performance standard in the rule, the CCR surface impoundment must be 
designed to have adequate H/H capacity to ensure that rainfall and 
watershed characteristics have been accounted for, the hydraulic 
ratings of all intake structures are adequate and free of obstruction, 
operating freeboard is adequate, all spillways and decant structures 
have adequate capacity, and all downstream hydraulic structures have 
adequate capacity. While not required, an antecedent flood study may be 
necessary to characterize the condition of the CCR surface impoundment 
under normal operating conditions.
    EPA recognizes that in many impoundment configurations, an inflow 
design flood may be limited to the direct precipitation that falls 
within the perimeter of the CCR surface impoundment during a storm 
event, due to the lack of storm water inflow routing from adjacent 
catchment areas. Other CCR surface impoundments may have storm water or 
other hydrologic contributions from various catchment areas or other 
sources. The final rule's hydraulic and hydrologic capacity standards 
require all CCR surface impoundments to have adequate hydraulic and 
hydrologic capacity to accommodate all contributory inflow to CCR 
surface impoundments, regardless of the inflow's origin.
    The hydraulic and hydrologic capacity requirements will minimize 
the potential for overtopping to occur from normal or abnormal 
operations, overfilling, wind and wave action, rainfall, and run-on, 
and will ensure that the unit is operated with appropriate 
consideration of these potentially adverse conditions. The Agency 
notes, however, that the operating freeboard of a CCR surface

[[Page 21392]]

impoundment is subject to fluctuations, deviating from original design 
assumptions and specifications. Additionally, EPA notes that routine 
maintenance and alterations of hydraulic structures associated with the 
CCR surface impoundments, e.g., decant structures and spillways, can 
adversely impact the hydrologic and hydraulic capacity of the CCR 
surface impoundment. At no point should the inflow design flood exceed 
the capacity of the CCR surface impoundment, regardless of fluctuations 
in freeboard, maintenance of hydraulic structures, or other potential 
obstructions to the hydraulic and hydrologic capacity of the unit. The 
owner or operator must account for operational changes or diminished 
capacity in the calculation of hydraulic and hydrologic capacity of the 
CCR unit.
3. Inflow Design Flood Control System Plan
    The owner or operator of an existing CCR surface impoundment must 
prepare an initial inflow design flood control system plan to document 
that the design and construction of the system will achieve the rule's 
performance standards no later than 18 months after the publication of 
this rule in the Federal Register. New CCR surface impoundments or 
lateral expansions of CCR surface impoundments must prepare an initial 
inflow design flood control system plan no later than the date of 
initial receipt of CCR in the unit. The owner or operator must obtain a 
certification from a qualified professional engineer that the plan 
meets all applicable requirements of the rule for inflow design flood 
control system plans. The plan must also be supported by appropriate 
engineering calculations. This documentation should also include 
references, and drawings regarding the identification of the design 
storm for the catchment area affecting the CCR surface impoundment and 
the CCR surface impoundment itself, a characterization of the rainfall 
abstractions, including but not limited to depression storage and 
infiltration in the upstream catchment area affecting the CCR surface 
impoundment. In addition, EPA expects supporting documentation to 
address the selection and basis of an appropriate run-off model and an 
appropriate run-on or run-off routing model; the identification and 
characterization of any intake or decant structures of the CCR surface 
impoundment; an appropriate characterization of the spillway(s) of the 
CCR surface impoundment and their capacity; and characterization of 
downstream hydraulic structures which ultimately receive the discharge 
from the CCR surface impoundment. Finally, the owner or operator must 
comply with the recordkeeping, notification and internet requirements 
specified in the rule for the plan.
    The owner or operator may amend the written inflow design flood 
control system plan at any time prior to receipt of CCR in the CCR 
unit, during the operating life of the CCR unit, during closure of the 
CCR unit, or following closure of the CCR unit provided the revised 
plan is placed in the facility's operating record. The owner or 
operator must amend the written inflow design flood control system plan 
whenever there is a change in the conditions that would substantially 
affect the written plan in effect. The owner or operator of the CCR 
surface impoundment must also periodically update the inflow design 
flood control system plan. The owner or operator must review or update 
an existing plan at a frequency no less than every five years. Changes 
in storm characteristics (e.g., intensity and duration) and upstream 
catchment area characteristics, hazard potential classifications, as 
well as build-out, operational changes, and diminishing available 
capacity, all have the potential to influence inflow design flood 
volumes and therefore the effectiveness of the existing inflow design 
flood control systems. A periodic review of the plan to address these 
and other factors is necessary to ensure that the hydrologic and 
hydraulic capacity of the unit is maintained over time. An update of 
the inflow design flood control system plan should document any 
modifications pertinent to the inflow design flood control system.
    The owner or operator may amend the written inflow design flood 
control system plan at any time and must place the revised plan in the 
facility's operating record. However, the owner or operator must amend 
the written inflow design flood control system plan whenever there is a 
change in the conditions that would substantially affect the written 
plan in effect. The owner or operator of the CCR unit must also review 
and, where necessary, update an inflow design flood control system plan 
every five years. As part of this review, the owner or operator must 
obtain certification from a qualified professional engineer must 
certify that the inflow design flood control system plan, and any 
subsequent amendments continues to meet the requirements of the rule. 
The date of completion of the initial plan is the basis for 
establishing the deadline to complete the first subsequent plan. The 
owner or operator may complete any required plan prior to the required 
deadline, and must place the completed plan into the facility's 
operating record within a reasonable amount of time.

I. Operating Criteria--Inspection Requirements for CCR Surface 
Impoundments

    EPA proposed structural stability requirements for CCR surface 
impoundments based on the long-standing MSHA requirements, with only 
minor modifications. These structural stability requirements were 
covered in various sections of the proposed rule (see specifically 
proposed Sec. Sec.  257.71, 257.72, 257.83, and 257.84). Section 257.83 
addressed requirements for periodic inspections of CCR surface 
impoundments. In proposing these requirements, the Agency concluded 
that periodic inspections were critical to ensure that any problems 
relating to structural stability are quickly identified and remedied to 
prevent catastrophic releases, such as occurred at Martins Creek, 
Pennsylvania and TVA's Kingston, Tennessee facility. The proposed rule 
required owners or operators to conduct: (1) Weekly inspections to 
detect potentially hazardous conditions or structural weakness; and (2) 
annual inspections to assure that the design, operation, and 
maintenance of the surface impoundment was in accordance with generally 
accepted engineering standards. EPA proposed that weekly inspections be 
conducted by a person qualified to recognize specific signs of 
structural instability and other hazardous conditions by visual 
observation and, if applicable, to monitor instrumentation. The 
proposed rule also required annual inspection reports from an 
independent registered professional engineer, certifying that the 
design, operation, and maintenance of the CCR surface impoundment was 
in accordance with generally accepted engineering standards. Consistent 
with the annual inspection requirements, EPA, as part of its 
recordkeeping requirements also proposed that owners or operators of 
CCR surface impoundments annually document and report on, among other 
things: (1) Changes in the geometry of the impounding structure; (2) 
location and type of instrumentation monitoring the unit; (3) the 
minimum, maximum and present depth and elevation of the impounded 
water, sediment or slurry for the reporting period; and (4) storage 
capacity of the impounding structure (see 75 FR at 35246).
    The annual inspection provisions also required that if a 
potentially hazardous

[[Page 21393]]

condition developed, the owner or operator must immediately take 
several actions: Eliminate the potentially hazardous condition; notify 
potentially affected persons and state and local first responders; 
notify and prepare to evacuate, if necessary, all personnel from the 
property who may be affected by the potentially hazardous condition(s); 
and direct a qualified person to monitor all instruments and examine 
the structure at least once every eight hours, or more often as 
required by an authorized representative of the state. Finally, the 
proposed rule required that inspection and monitoring reports be 
maintained in the facility operating record and placed on the 
facility's publicly accessible Internet site as well as promptly 
reporting the results of the inspection or monitoring to the state.
    EPA specifically requested comment on whether to cover all CCR 
impoundments for stability (including the inspection requirements), 
regardless of height and storage volume, whether to use the cut-offs in 
the MSHA regulations, or whether other regulations, approaches, or size 
cut-offs should be used. The Agency further requested commenters who 
believed that other regulations or size cut-offs should be used (and 
not the size cut-offs established in the MSHA regulations) to provide 
the basis and technical support for their position. (75 FR 35176, 
35223). In response to EPA's general solicitation for alternative size 
cut-offs, the Agency received little response. However, many commenters 
questioned EPA's decision to require inspections for all CCR surface 
impoundments, given that the other structural stability requirements 
were triggered only if the CCR unit exceeded the proposed size 
threshold (consistent with MSHA requirements). Commenters argued that 
there was no basis to require inspections of all CCR surface 
impoundments given that units below the specified size threshold had a 
much lower risk of catastrophic failure. A more limited requirement the 
commenter's argued, was supported by MSHA's decision to regulate only 
those ``larger'' sized units. Other commenters argued that inspection 
timeframes should take into account site specific conditions at the 
site and be based on the recommendations of an independent registered 
professional engineer. Commenters reasoned that while, in theory, a 
short inspection interval (i.e., a weekly inspection) should increase 
the chances of finding an adverse condition, the judgment of a 
qualified professional engineer to establish the frequency and focus, 
as well as the purpose of the dam safety inspection was a far more 
effective method for detecting and preventing the development of a 
potentially adverse situation. Still other commenters questioned the 
overall value of a weekly inspection if, as proposed, no documentation 
of the results was required.
    In reviewing the proposed regulatory language, it appears an error 
was made. Although the preamble generally stated that the proposed 
regulatory requirements addressing stability (which included 
inspections) applied only to those CCR surface impoundments exceeding 
the specified size threshold established by the MSHA regulations, the 
regulatory text required inspections for all CCR units. The final rule 
requires weekly general inspections and monthly instrumentation 
inspections to be conducted for all CCR surface impoundments. Periodic 
inspections of all CCR units are a necessary practice to ensure that 
the overall structural integrity of the CCR unit is maintained and that 
actual and potential structural weaknesses and other hazardous 
conditions are quickly identified and remediated throughout the active 
life of the unit. All CCR surface impoundments pose some risk of 
release--whether from a catastrophic failure or from a more limited 
structural failure, such as occurred at Duke Energy's Dan River plant. 
Periodic inspections are a generally accepted, prudent engineering 
practice that will significantly reduce the risks of such failures; 
during the Assessment Program, EPA discovered that many facilities 
routinely conduct some sort of periodic inspection and monitoring, 
although the frequency varied widely between facilities. The final rule 
merely codifies this practice, by establishing a consistent minimum 
timeframe. EPA is therefore requiring that all CCR surface impoundments 
be inspected by a qualified person both weekly (for visual signs of a 
potentially adverse condition) and monthly (for instrumentation 
monitoring). Consistent with the proposed rule, EPA is also requiring 
annual inspections for all CCR surface impoundments that exceed the 
specified size threshold of: (1) A height of five feet and a storage 
capacity of 20 acre-feet; or (2) a height of 20 feet, must also be 
inspected no less than annually by a qualified professional engineer. 
These inspection requirements are generally being promulgated as 
proposed, with minor technical clarifications.
    The final inspection requirements have been drawn heavily from 
guidelines established by FEMA for dam safety, under which maintaining 
structural integrity involves continuous evaluation of the unit, based 
on periodic inspections. To be most effective, FEMA suggests, and EPA 
concurs, that inspections be varied with respect to both the time 
interval between inspections and the level of detail of the inspection. 
FEMA guidance, in part, suggests that inspections can be categorized as 
either: Visual observations to identify abnormal conditions (i.e., 
informal inspections); field inspections by a professional engineer 
(i.e., intermediate inspections); and a technical review to determine 
if the unit meets current and accepted design criteria and practices 
(i.e., formal inspection).\114\ In general, FEMA recommends that 
inspections focusing on visual observations should be conducted often 
(e.g., weekly) while more substantive technical evaluation should be 
conducted every year to every five years depending on the engineering 
analyses required. (See also the preamble discussion on the 
requirements specified in Sec. Sec.  257.73 and 257.74 of this rule, in 
particular the discussion addressing the five year time interval for 
structural stability and factor of safety reassessments.)
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    \114\ See ``Federal Guidelines for Dam Safety'' Federal 
Emergency Management Agency. (Reprinted April 2004).
---------------------------------------------------------------------------

    For the reasons discussed above, EPA has concluded, consistent with 
FEMA guidelines, that routine inspections of all CCR units are 
necessary to ensure that the units are safely operated and that issues 
that could disrupt the safety and continuing operation of these units 
are promptly identified and remediated. Accordingly, the final rule 
requires both weekly inspections and monthly instrumentation 
inspections to be conducted at all CCR surface impoundments to confirm 
that they are operating safely. These inspections must be conducted by 
a qualified person trained to recognize specific signs of structural 
instability and other hazardous conditions by visual observation and 
if, applicable monitor instrumentation. EPA is also retaining the 
annual inspection requirement for CCR surface impoundments exceeding 
the specified size threshold established in this rule. This inspection 
must be conducted and certified by a qualified professional engineer. 
Units exceeding this size threshold pose a higher degree of risk of 
release of CCR to the environment than other types of CCR surface 
impoundments (e.g., incised or ``small'' CCR units) and as such warrant 
additional regulatory control and oversight.

[[Page 21394]]

    The final rule requires that both weekly inspections of the CCR 
unit and monthly monitoring of CCR unit instrumentation be initiated 
within 6 months of the publication of the rule.
    Within nine months of the publication of the rule, the owner or 
operator must complete the initial annual inspection of the CCR unit. 
Initial annual inspection requires the retaining of a professional 
engineer along with the familiarization of the engineer with the 
facility and CCR units. Additionally, the annual inspection should not 
be conducted unless weekly inspection and monthly instrumentation 
monitoring has been initiated and established in order to generate a 
body of information for the professional engineer to consider. 
Furthermore, in some cold-weather regions of the United States, weather 
may inhibit adequate inspection of CCR units, whether through snow or 
ice cover. EPA is establishing a timeframe of nine months after the 
publication of the rule so as to allow for adequate weather conditions 
for inspection.
1. Surface Impoundment Inspection Requirements
a. Weekly Inspections
    As presented in the proposed rule and finalized here, this rule 
requires all CCR surface impoundments to be examined by a qualified 
person at least once every seven days for any appearance of actual or 
potential structural weakness or other conditions that are disrupting 
or that have the potential to disrupt the operation or safety of the 
CCR unit. The results of the inspection by a qualified person must be 
recorded in the facility's operating record.
    Weekly inspections are intended to detect, as early as practicable, 
signs of distress in a CCR surface impoundment that may result in 
larger, more severe conditions. They are also designed to identify 
potential issues with hydraulic structures that may affect the 
structural safety of the CCR surface impoundment and impact the 
hydraulic and hydrologic capacity of the CCR surface impoundment. The 
early detection of signs of structural weaknesses is an essential 
preventative measure which helps to impede structural failure. The 
required weekly inspections are designed to identify such signs of 
structural weakness before they develop into larger, debilitating 
concerns in the structural stability of the dike.
    Appearances of structural weakness may include, but are not limited 
to: (1) Excessive, turbid, or sediment-laden seepage; (2) signs of 
piping and other internal erosion; (3) transverse, longitudinal, and 
desiccation cracking; (4) slides, bulges, boils, sloughs, scarps, 
sinkholes, or depressions: (5) Abnormally high or low pool levels; (6) 
animal burrows; (7) excessive or lacking vegetative cover; (8) slope 
erosion; and (9) debris.
    In addition, EPA is also adopting a new provision that requires the 
qualified person to inspect the discharge of all outlets of hydraulic 
structures which pass underneath the base of the CCR surface 
impoundment or through the dike of the CCR unit for abnormal 
discoloration, flow, or discharge of debris or sediment. The 
requirement is being added to aid in the identification of any internal 
or sub-surface issues which cannot be reasonably identified in a 
routine visual inspection. Abnormal discharges from hydraulic 
structures are often an indication of potential issues with the sub-
surface or internal integrity of the structure. Hydraulic structures, 
particularly corrugated metal pipe, are subject to deterioration and 
corrosion over time and, as deterioration proceeds, the hydraulic 
structure becomes more susceptible to collapse, translation, or 
malfunction. Issues with hydraulic structures within the dike may 
exacerbate structural or operational issues with the CCR surface 
impoundment due to the significant internal deterioration of the dike 
via the hydraulic structure. As an example, on February 2, 2014, Duke 
Energy's Dan River Fossil Plant experienced a structural collapse of a 
corrugated metal storm water discharge pipe which passed underneath the 
interior of a CCR surface impoundment. The subsequent collapse of the 
base of the CCR surface impoundment led to a massive release of CCR to 
the environment. Additionally, the adjacent dike of the CCR surface 
impoundment was severely damaged due to the erosion of the upstream 
slope.
    Further, an owner or operator may want to consider inspections 
outside of the weekly, seven-day schedule if an unanticipated event, 
such as a flood, earthquake, or vandalism occurs on the site. While 
rare in occurrence, these events may increase the chances that a 
potential structural stability issue has arisen. Prudent CCR management 
practices dictate that a visual assessment is warranted after such 
events. For example, after a large flood (considered a flood with a 
return period of equal or greater frequency of ten years) there is 
potential for damage, including structural damage to the CCR surface 
impoundment, caused by increased reservoir levels that inundate areas 
infrequently inundated. The slopes of the dike should be inspected to 
ensure that no significant erosion has occurred due to the flood, or 
that any large debris or sediment has been deposited on the dike. An 
inspection should also be conducted following an earthquake where 
earthquake damage is observed or can be reasonably expected, where 
ground motion is felt at the CCR surface impoundment or in nearby 
locations, or following established magnitude-epicenter distance 
relationships.\115\
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    \115\ The U.S. Army Corps of Engineers have developed useful 
criteria for post-earthquake inspections, specifically their 
published magnitude-epicenter distance criteria in Table 11.1 of 
``Safety of Dams--Policy and Procedures,'' ER 1110-2-1156, 31 March 
2014.\115\ The criteria stipulate when the dam (or in the case of 
this rule, CCR surface impoundment) should be inspected.
---------------------------------------------------------------------------

b. Monthly Instrumentation Inspection
    In a departure from the proposed rule, EPA is requiring the 
monitoring of all instrumentation supporting the operation of the CCR 
unit to be conducted by a qualified person no less than once per month. 
This is a change from the proposal which required instrumentation to be 
monitored no less than every seven days.
    Many commenters argued that requiring inspections every seven days 
was excessive, and that, based on FEMA guidelines for dam safety, a 
more reasonable timeframe would be once per month for CCR surface 
impoundments with a hazard potential rating of ``high'' and quarterly 
for those CCR surface impoundments with a hazard potential rating of 
``significant.'' In considering these comments, the Agency was 
influenced by a number of factors including the FEMA guidelines 
suggested by the commenters. Also weighing heavily in EPA's decision 
were the observations made as part of the Assessment Program, which 
revealed that many CCR units are equipped with only ``basic'' measuring 
devices such as piezometers and pool elevation and freeboard 
instrumentation and not the more sophisticated (i.e., sensitive) 
measuring devices for measuring pressure, seepage, internal movement, 
slope movement; and vibration. These findings strongly suggested to the 
Agency that, given the status of current instrumentation employed at 
CCR facilities, weekly monitoring would be excessive, impractical, 
and--of greatest significance--unlikely to indicate any measurable 
changes in structural stability in such a short timeframe. EPA, 
therefore, agrees that a monthly timeframe is a more appropriate 
interval for detecting discernible or significant changes in the 
operation of the CCR

[[Page 21395]]

unit. EPA has not, however, differentiated between high, significant, 
and low hazard potential CCR surface impoundments in the requirement 
that instrumentation be monitored monthly, as commenters suggested. 
Through the assessment effort, EPA identified that typically low hazard 
potential CCR surface impoundments were monitored less frequently than 
high- or significant hazard potential CCR surface impoundments by the 
owner or operator. Additionally, these low hazard potential CCR surface 
impoundments less commonly were equipped with sophisticated monitoring 
instrumentation, including remote monitoring instrumentation which 
would allow the owner or operator to monitor the unit from a remote 
location. Based on these observations, along with the limited burden 
that instrumentation monitoring places on the owner or operator, the 
rule requires all CCR surface impoundments with instrumentation to be 
monitored monthly.
c. Annual Inspections
    The rule requires owners or operators of any CCR surface 
impoundments exceeding the MSHA size threshold (i.e., a height of five 
feet or more and a storage volume of 20 acre-feet or more; or a height 
of 20 feet or more) to conduct annual inspections of the CCR unit 
throughout its operating life. These annual inspections are focused 
primarily on the structural stability of the CCR surface impoundment 
and must ensure that the operation and maintenance of the CCR surface 
impoundment is in accordance with recognized and generally accepted 
good engineering standards. Inspections must be conducted and certified 
by a qualified professional engineer.\116\ Incised CCR surface 
impoundments, as defined in Sec.  257.53 are not subject to the annual 
inspection requirements. Incised units present lower risks of 
structural failure, and so weekly inspections are sufficient to address 
any risks associated with these CCR units.
---------------------------------------------------------------------------

    \116\ For purposed of this requirement, qualified means an 
individual experienced in the operation and maintenance of dams and 
who has been trained to recognize signs of concern and structural 
weakness by visual observation, and if applicable, to monitor 
instrumentation.
---------------------------------------------------------------------------

    Annual inspections of any CCR surface impoundment must include, at 
a minimum: (1) A review of all previously generated information 
regarding the status and condition of the CCR unit, including, but not 
limited to, all operating records and publicly accessible internet site 
entries, design and construction drawings and other documentation; (2) 
a thorough visual inspection to identify indications of distress, 
unusual or adverse behavior, or malfunction of the CCR unit and 
appurtenant structures; and (3) a thorough visual inspection of 
hydraulic structures underlying the base of the CCR unit and passing 
through the dike of the CCR unit for structural integrity and continued 
safe and reliable operation. Additionally, following each inspection, 
the qualified professional engineer must prepare an inspection report 
which documents the following: (1) Any changes in geometry of the 
impounding structure since the previous annual inspection; (2) the 
location and type of existing instrumentation and the maximum recorded 
readings of each instrument since the previous annual inspection; (3) 
the approximate minimum, maximum, and present depth and elevation of 
the impounded water and CCR since the previous annual inspection; (4) 
the storage capacity of the impounding structure at the time of 
inspection; (5) the approximate volume of the impounded water and CCR 
at the time of the inspection; and (6) any appearances of an actual or 
potential structural weakness of the CCR unit, in addition to any 
existing conditions that are disrupting or have the potential to 
disrupt the operation and safety of the CCR unit and appurtenant 
structures; and (7) any other change(s) which may have affected the 
stability or operation of the impounding structure since the previous 
annual inspection.
    This last set of requirements was originally presented in Sec.  
257.84 of the proposed rule (i.e., recordkeeping requirements), 
however, the Agency has moved these requirements to the annual 
inspection section of the rule because (1) these requirements apply 
only to CCR surface impoundments exceeding the specified size 
threshold, rather than all CCR surface impoundments, as proposed; (2) 
must be reported annually; and (3) are more appropriately housed in the 
inspection section.
    The owner or operator of existing CCR surface impoundments must 
ensure that the initial annual inspection by a qualified professional 
engineer is completed and documented with a report no later than nine 
months after the publication of the rule. EPA established this 
timeframe for completing an initial annual inspection based on its 
experience with the Assessment Program. In an effort similar to 
conducting an initial annual inspection, the following tasks were 
generally completed within three months: Retaining the services of a 
qualified professional engineer, developing a scope of work, reviewing 
existing documentation on the CCR unit, conducting a thorough field 
inspection, and completing an inspection report. Owners and operators 
of new CCR surface impoundment must commence annual inspections no 
later than one year from the initial placement of CCR into the new 
unit. An annual inspection is not required in any calendar year in 
which the five year structural stability reassessment is also required 
to be completed. (See Sec. Sec.  257.73 and 257.74.) The report which 
the qualified professional engineer has certified must be placed in the 
facility's operating record and placed on the facility's publicly 
accessible internet site. An annual inspection is considered complete 
when the inspection report has been placed in the facility's operating 
record. Finally, if a deficiency is identified during an inspection, 
the owner or operator must take immediate measures to remedy the 
structural weakness or disrupting condition as soon as feasible.

J. Operating Criteria--Inspections for CCR Landfills

    Under 40 CFR part 258, EPA does not require specific inspection 
requirements for MSWLFs. Rather, EPA relies on states to establish 
their own inspection criteria and frequency of inspections to ensure 
protection of human health and the environment. It is the Agency's 
understanding that many states require owners or operators of MSWLFs to 
conduct either daily, weekly, quarterly and annual inspections of these 
units to ensure that the design, construction, operation, and 
maintenance complies with all requirements. In addition, based on a 
review of selected state regulations most states conduct state 
inspections of operating landfills no less than annually.
    Under the proposed subtitle D option, EPA did not propose to 
require mandatory inspections of new or existing landfills or any 
lateral expansion. However, under the subtitle C option, EPA proposed 
to apply the requirements of Sec.  264.303 to permitted CCR landfills. 
Specifically, these requirements stated that CCR landfills while in 
operation would be required to be inspected weekly and after storms to 
detect evidence of any of the following: (1) Deterioration, 
malfunctions, or improper operation of run-on and run-off control 
systems; (2) proper functioning of wind dispersal control systems, 
where present; and (3) the presence of leachate in and proper 
functioning of the leachate collection and removal system where 
present. (See proposed Sec.  264.1306, 75 FR 35257).

[[Page 21396]]

    Upon further evaluation, the Agency has decided, consistent with 
the weekly inspection requirements proposed for CCR landfills under the 
subtitle C option, as well as many state requirements for MSWLFs, to 
require all existing and new CCR landfills and any lateral expansion to 
conduct, at intervals not exceeding seven days, inspections by a 
qualified person for any appearances of actual or potential structural 
weakness or any other conditions which are disrupting or have the 
potential to disrupt the operation or safety of the CCR landfill. In 
addition, EPA is also requiring inspections by a qualified professional 
engineer at intervals not exceeding one year to ensure that the design, 
construction, operation, and maintenance of the CCR landfill is 
consistent with recognized and generally accepted good engineering 
standards. This inspection must include a review of all data in the 
operating record as well as a visual inspection of the unit to identify 
signs of distress or malfunction that is or potentially could affect 
the safe operation of the unit. The qualified professional engineer 
must then also prepare a report to identify and discuss the findings of 
the inspection as well as a discussion of potential remedies for 
addressing any deficiencies discovered during the inspection. The 
Agency has concluded that all CCR landfills should be routinely 
inspected to ensure that they are operating as designed and are being 
maintained in compliance with the federal criteria.
    The Agency is promulgating these inspection requirements based on: 
(1) A review of state municipal landfill inspection requirements; and 
(2) comments from parties that clearly supported inspections of all CCR 
landfills. The Agency reviewed MSWLF inspection checklists in a 
selected number of states to assess the scope of these inspections. The 
Agency also conducted a preliminary review of state MSWLF regulations 
for New York, Pennsylvania, Ohio, Wisconsin, Illinois, Missouri, North 
Dakota and California. All of these states require MSWLF owners or 
operators to conduct a either daily, weekly, monthly, quarterly and 
annual inspections addressing the following: (1) Proper placement of 
the waste; (2) slope stability and erosion control; (3) surface water 
percolation is minimized (i.e. reduce ponding); (4) liner systems and 
leachate collection systems are properly operated and maintained; (5) 
water quality monitoring systems are maintained and operating; (6) dust 
is controlled; and (7) a plan is in place to promptly address and 
correct problems and deficiencies discovered during the inspection. The 
Agency also noted during its review of state regulations that states 
reserve the right to inspect landfills at any time and routinely 
conduct state inspections on a no less than annual basis. CCR landfills 
present at least the same level of risks as MSWLFs, and while the 
operations may differ, both operating systems are equally susceptible 
to malfunction. Weekly inspections of all CCR landfills by a qualified 
person are therefore equally necessary to ensure that groundwater 
monitoring, run-on and run-off controls, liner systems, and leachate 
collection systems are operated and maintained to reduce adverse 
environmental and human health impacts.
    This rule also requires that owners or operators of all existing 
and new CCR landfills and any lateral expansion conduct an annual 
inspection, certified by a qualified professional engineer, to assure 
that these units are designed, constructed, operated, and maintained 
throughout their operating life to ensure protection of human health 
and the environment. The Agency finds that annual inspections for these 
units are justified for a number of reasons. First, CCR landfills are 
large engineered units that require that a variety of design and 
operating parameters be assessed to assure that the CCR landfill is 
operating as designed. Of particular concern to the Agency is the fact 
that coal ash is a fine grained material that may have the potential to 
compact and clog leachate collection systems (see: ``Operations and 
Maintenance Guidelines for Coal Ash Landfills'' Christopher Hardin, et. 
al. 2011 World of Coal Ash Conference. May 2011). It is reasonable 
therefore that the rule requires annual inspections to assure that 
these liner and leachate systems are assessed to assure that they are 
performing their functions as designed. Second, a formal annual 
inspection would review data collected during weekly inspections and 
determine if any remedial actions are need to address deficiencies. 
Third, the annual review by a qualified professional engineer ensures 
that a detailed level of engineering analysis of operating conditions 
are evaluated which could lead to recommendations to address design or 
operating issues that need attention.

K. Groundwater Monitoring and Corrective Action

    EPA is finalizing groundwater monitoring and corrective action 
requirements to ensure that groundwater contamination at new and 
existing CCR units will be detected and cleaned up as necessary to 
protect human health and the environment. These requirements reflect 
Congressional intent that protection of groundwater be a prime 
objective of any new solid waste regulations. As stated in the 
proposal, EPA's damage cases and risk assessments indicate there is 
significant potential for CCR landfills and CCR surface impoundments to 
leach hazardous constituents into groundwater, impair drinking water 
supplies and cause adverse impacts on human health and the environment. 
Indeed, groundwater contamination is one of the key environmental and 
human health risks EPA has identified with CCR landfills and CCR 
surface impoundments. 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, in order for a CCR landfill or CCR surface impoundment 
to show no reasonable probability of adverse effects on health or the 
environment, a system of routine groundwater monitoring to detect any 
contamination from a CCR unit, and corrective action requirements to 
address identified contamination, are essential.
    EPA proposed to require that a system of monitoring wells be 
installed at all new and existing CCR units. The regulation would 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 CCR units. 
The Agency proposed a groundwater monitoring program consisting of 
detection monitoring and assessment monitoring, and a corrective action 
program. This phased approach to groundwater monitoring and corrective 
action programs provides 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 groundwater, while 
protecting human health and the environment.
    EPA largely based these proposed groundwater monitoring 
requirements on those for MSWLFs in the 40 CFR part 258 criteria, 
albeit with certain modifications to tailor the requirements to the 
case at hand. In particular, the possibility that a state may lack a 
permit program for CCR units made it impossible to include some of the 
alternatives available in 40 CFR part 258, which establish alternative 
standards that allow a state, as part of

[[Page 21397]]

its permit program to tailor the default requirements to account for 
site specific conditions at the individual facility. EPA also sought to 
tailor the proposed requirements for CCR units, by incorporating 
certain provisions from the interim status regulations, which operate 
in the absence of a permit, and by including in several of the proposed 
requirements, a certification by an independent registered professional 
engineer that the rule's requirements had been met.
    In the proposed rule, the Agency required facilities to install a 
groundwater monitoring system that met a specified performance standard 
and that consisted of a minimum of one upgradient and three 
downgradient wells at all CCR units. EPA acknowledged in the proposal 
that the design of an appropriate groundwater monitoring system is 
particularly dependent on site conditions relating to groundwater flow, 
and on the development of a system that has a sufficient number of 
wells, installed at appropriate locations and depths, to yield 
groundwater samples from the uppermost aquifer that represent the 
quality of background groundwater that has not been affected by 
contaminants from a CCR unit. EPA's existing requirements under 40 CFR 
parts 258 and 264 recognize this, and because they operate in a 
permitting context, these requirements provide more flexibility in 
establishing groundwater monitoring systems. But because the same 
guarantee of permit oversight is not available under the criteria 
developed for the proposal, EPA proposed to establish a minimum 
requirement based on the part 265 interim status regulations, which are 
self-implementing. Long 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. 
EPA also noted that in many instances a more detailed groundwater 
monitoring system will need to be in place, and EPA therefore proposed 
requiring a certification by the independent registered professional 
engineer that the groundwater monitoring system is designed to detect 
all significant groundwater contamination.
    EPA also proposed to require that owners and operators of CCR units 
establish consistent sampling and analysis procedures to determine 
whether a statistically significant increase in the level of a 
hazardous constituent(s) has occurred, indicating the presence of 
groundwater contamination.
    As noted, EPA proposed a phased approach to monitoring. The first 
phase is detection monitoring where indicators would be monitored to 
determine whether groundwater was potentially being contaminated. The 
parameters EPA proposed to be used as indicators of groundwater 
contamination were the following: Boron, chloride, conductivity, 
fluoride, pH, sulfate, sulfide, and total dissolved solids (TDS). In 
selecting the parameters for detection monitoring, EPA chose 
constituents that are present in CCR and would rapidly move through the 
subsurface, and thus provide an early detection of whether contaminants 
were migrating from the CCR unit. Under the proposed rule, monitoring 
would be required no less frequently than semiannually.
    When a statistically significant increase over background levels is 
detected for any of these parameters, the proposed rule required the 
facility to begin an assessment monitoring program to determine if 
releases of CCR constituents of concern had occurred. The parameters 
that were proposed for assessment monitoring were aluminum, antimony, 
arsenic, barium, beryllium, boron, cadmium, chloride, chromium, copper, 
fluoride, iron, lead, manganese, mercury, molybdenum, pH, selenium, 
sulphate (sic), sulfide, thallium, and total dissolved solids.
    The proposed rule also required that whenever monitoring results 
indicate a statistically significant level exceeding the groundwater 
protection standard for any of these parameters, the owner or operator 
must start the process for cleaning up the contamination, and initiate 
an assessment of corrective action remedies. The proposed rule required 
that the assessment of correction action remedies be initiated within 
90 days and then completed within 90 days.
    EPA proposed that the assessment of corrective measures must 
consider a number of factors, including the effectiveness, performance, 
and time needed for the potential remedies. As part of the assessment 
of corrective measures, the owner or operator was required to identify 
the source of the release. The owner or operator was also required to 
gather data on plume definition, fate of the contaminants, stratigraphy 
and hydraulic properties of the aquifer. The owner or operator also was 
required to consider whether immediate measures to limit further plume 
migration or measures to minimize further introduction of contaminants 
to groundwater would be necessary. EPA also proposed to require the 
owner or operator to provide notification of the corrective measures 
assessment to the State Director, place the corrective measures 
assessment in the operating record and on the owner's or operator's 
publicly accessible internet site, and discuss the results of the 
corrective measures assessment in a public meeting with interested and 
affected parties.
    Based on the results of the corrective measures assessment, EPA 
proposed to require the owner or operator to select a remedy based on a 
number of factors, including: the long- and short-term effectiveness 
and protectiveness of the potential remedy, along with the degree of 
certainty that the remedy will prove successful; the effectiveness of 
the remedy in controlling the source to reduce further releases; the 
ease or difficulty of implementing a potential remedy; the degree to 
which community concerns are addressed by a potential remedy; and 
potential risks to human health and the environment from exposure to 
contamination prior to completion of the remedy. The owner or operator 
was also required to specify as part of the selected remedy a schedule 
for initiating and completing remedial activities.
    Under the proposed rule, implementing the corrective action program 
required the owner or operator to establish and implement a corrective 
action groundwater monitoring program; implement the corrective action 
remedy selected; and take any interim measures necessary to ensure the 
protection of human health and the environment, all according to the 
schedule the owner or operator developed during the assessment of 
corrective measures.
    The proposed rule also required that the owner or operator must 
demonstrate that concentrations of constituents have not exceeded the 
groundwater protection standards for three consecutive years in order 
to support a determination that the remedy is complete.
    The majority of the commenters supported ``appropriate groundwater 
monitoring standards for CCR waste management units'' and the 
development of such standards under a RCRA subtitle D framework. 
Comments were received on various parts of the groundwater monitoring 
scheme laid out in the proposed rule. The majority of comments received 
requested EPA to provide ``more flexibility'' to the proposed 
requirements. Many commenters wanted the states to be more involved 
with the process and provided comments suggesting that additional 
``flexibility,'' such as is provided in the 40 CFR part 258

[[Page 21398]]

regulations for MSWLFs as part of the permitting process, be extended 
to CCR units. For example, commenters wanted states to have the 
authority to add or drop monitoring constituents; approve alternative 
schedules; modify the number of wells needed; allow variances; allow 
alternatives to the point of compliance specified in the rule; employ 
alternative methods to detect potential groundwater contamination, such 
as leak detection systems; allow alternatives to the statistical 
methods used to determine whether groundwater contamination has 
occurred; and to replace the qualified professional engineer role in 
the certification process.
    For the final rule, EPA has developed a groundwater monitoring 
program that is flexible and allows facilities to design a system that 
accounts for site specific conditions within specific parameters. The 
final rule establishes an overall performance standard that the system 
must meet, lays out the minimum requirements of an effective system, 
and requires the owner or operator to design a system that achieves 
that overall performance standard based on a full characterization of 
site conditions.
    As described in more detail below, in certain cases, EPA was able 
to develop performance standards to serve as ``more flexible'' 
alternatives to the technical specifications laid out in the proposal. 
In these instances, the available information allowed the Agency to 
develop performance standards that were sufficiently objective and 
determinate that EPA could conclude that the 4004(a) standard would be 
met nationwide.
    However, many of the commenters' requests related to alternatives 
that would be less stringent than the minimum criteria laid out in the 
proposal and were based on arguments that state regulators (or 
facilities) should be allowed to ``tailor'' those requirements to sites 
that did not need those particular requirements. As explained at length 
in the proposal, EPA is concerned that provisions allowing such 
modifications are particularly susceptible to abuse, since in many 
cases the provisions could allow substantial cost avoidance. In the 
absence of a mandated state oversight mechanism to ensure that the 
suggested modifications are technically appropriate, these kinds of 
provisions can operate at the expense of protectiveness. In Unit II of 
this preamble, EPA explains the extent of our authority to establish 
criteria under RCRA sections 1008(a)(3) and 4004(a), including the 
implications associated with the lack of any authority to establish a 
program analogous to part 258, which relies on approved states to 
implement the federal criteria through a permitting program. As a 
result of the statutory structure, this rule is self-implementing and 
is designed to operate to ensure that facilities will manage CCR in a 
manner that achieves the 4004(a) standard even in the absence of any 
regulatory entity available to judge the reasonableness of the desired 
alternatives. While some states currently do have programs for the 
regulation of CCR, which in some cases may be more stringent than this 
final rule, the federal program must be defensible on the record in 
place at the time the final rule is adopted. Based on the current 
rulemaking record, in most cases EPA lacked the information necessary 
to defend the commenters' less stringent alternatives (i.e., the 
commenters' requested ``flexibilities'') to the minimum technical 
criteria specified in this rule for these units. Under both the 
subtitle C and part 258 programs, EPA can rely on subsequent 
proceedings to develop the information necessary to support such 
tailoring. This is clearly neither contemplated nor authorized under 
the regulatory program relevant to this rule.
    In addition, given the extremely technical nature of these 
requirements, EPA remains concerned that such provisions would render 
the requirements appreciably more difficult for citizens to effectively 
enforce. Nevertheless, working within these constraints this rule 
specifically allows the qualified PE to design a system that accounts 
for site conditions within the parameters of the minimum technical 
criteria, and EPA has added language to the regulation that expressly 
clarifies this. Moreover, states that have programs can continue to 
impose more stringent requirements, and thus can require, for example, 
additional monitoring wells, monitoring of additional aquifers, and 
inclusion of additional parameters to the detection monitoring list or 
the assessment monitoring list. The following discussion addresses in 
more detail the technical requirements under groundwater monitoring and 
corrective action in the final rule.
1. Applicability
    Consistent with the provisions in the proposed rule, the final rule 
requires a system of monitoring wells to be installed at all CCR 
landfills, CCR surface impoundments and lateral expansions. Existing 
CCR units must install the groundwater monitoring system, develop their 
groundwater sampling and analysis procedures, develop background levels 
for appendix III and appendix IV constituents, and begin detection 
monitoring (Sec.  257.90 through Sec.  257.94) within two years of the 
effective date of this rule. The proposed rule required that existing 
CCR units comply with the groundwater monitoring requirements within 
one year of the effective date. EPA proposed one year believing that it 
would be feasible for facilities to install the necessary systems. EPA 
also believed that a one year timeframe would ensure that existing CCR 
disposal facilities begin monitoring groundwater as soon as possible, 
so that releases from existing CCR units are detected and addressed. 
Comments received on this issue argued that the one-year timeframe was 
not sufficient to complete a hydrogeologic study and develop a 
monitoring plan. Several commenters requesting more time mentioned 
staffing shortages and limited contractor and lab resources. One state, 
referencing its experience relating to development and implementation 
of groundwater monitoring systems, said that a one year timeframe to 
investigate, design and submit and obtain approval for the installation 
of an effective groundwater monitoring system was unreasonable. Most 
commenters thought that a timeframe of two years was reasonable. After 
review of the comments received on this issue and careful reexamination 
of the actual requirements in the final rule, EPA agrees that a one-
year timeframe is not feasible, and has decided to extend the 
timeframes for completing installation of the system, including 
background monitoring, to two years. As important as it is to begin 
detecting and addressing releases to groundwater, it is equally 
important that these complex systems be designed and installed 
correctly. That generally entails a number of activities, many of which 
must occur sequentially, including: determining the uppermost aquifer, 
deciding whether to install a single or multi-unit monitoring system, 
collecting and evaluating hydrogeological information that can be used 
to model the site, characterizing the site geology, characterizing the 
groundwater flow beneath the site, determining the flow direction and 
hydraulic gradient, establishing horizontal and vertical flow 
direction, determining hydraulic conductivity, determining groundwater 
flow rate, determining the monitoring wells placement, selecting the 
drilling method, designing the monitoring wells, developing sampling 
and analysis procedures, choosing a statistical method for evaluating 
the data and

[[Page 21399]]

beginning detection monitoring. We also recognize that in some states, 
the state may require the owner or operator to receive state approval 
before they can install a groundwater monitoring system. Two years is a 
more reasonable timeframe in which to carry out these activities. New 
CCR landfills, new CCR surface impoundments and any lateral expansion 
must comply with these same requirements (Sec. Sec.  257.90 through 
257.94) before any CCR can be placed in the CCR unit.
    Consistent with the proposal, the final rule also requires that the 
owner or operator of the CCR facility annually certify that each CCR 
unit is in compliance with the groundwater monitoring and corrective 
action provisions and provide a copy of this certification to the State 
Director. Because this is a self-implementing rule that relies on 
citizen enforcement, it is important for the owner or operator of the 
facility to periodically document that they are in compliance with the 
existing groundwater monitoring requirements, and an annual 
certification is the easiest and most effective way to achieve this. 
While the groundwater monitoring data will be made available on the 
owner or operator's publicly accessible Web site and in the operating 
record of the facility, the analysis of these data is complicated and 
requires a certain level of scientific expertise to analyze the data 
correctly. As such, a document that serves as both an interpretative 
record of scientific analysis and regulatory compliance is critically 
important to the successful implementation of a self-implementing rule 
that is to be enforced exclusively by citizens and the states. For 
similar reasons, the certification must also be placed in the operating 
record, provided to the State Director, and posted on the owner or 
operator's publicly accessible Web site.
    The groundwater monitoring requirements must be met throughout the 
active life of the CCR unit, as well as during the closure and post-
closure care period.
    EPA has added a new provision to Sec.  257.90 to address the 
corrective action requirements that apply when CCR have been released 
into the environment, such as from the kind of structural failure that 
occurred with TVA's Kingston Fossil Fuel plant release, or from the 
kind of release that occurred in North Carolina at the Dan River. EPA 
inadvertently drafted the corrective action requirements in the 
proposed rule to apply exclusively upon detection of groundwater 
contamination caused by a leaking unit. However, there is no reason to 
establish different corrective action provisions for conducting clean-
up operations for different kinds of releases; the same general process 
is applicable to all kinds of releases.
    The new provision requires that in the event of a release from a 
CCR unit, the owner or operator must immediately take all necessary 
measures to control the source(s) of releases so as to reduce or 
eliminate, to the maximum extent practicable, further releases of 
contaminants into the environment. The owner or operator of the CCR 
unit is also required to comply with all of the relevant corrective 
action requirements in Sec. Sec.  257.96, 257.97, and 257.98.
2. Groundwater Monitoring System Requirements
    EPA received comments that supported establishing more prescriptive 
requirements for the design of the groundwater monitoring system. For 
example, one commenter argued that three downgradient wells are 
insufficient to ensure detection of leakage from the very large 
disposal units typically used for CCR; due to uncertainty in flow 
directions, the perimeter of the CCR unit must be monitored on its 
cross-gradient, as well as downgradient sides. The commenter suggested 
that the minimum number of non-background monitoring wells should 
instead be three, plus one for every 500 feet of downgradient and 
cross-gradient perimeter of the CCR unit (i.e., if the perimeter length 
adds up to 1200 feet, the minimum number of wells would be five), and 
that wells should be spaced no more than 500 feet apart along the 
downgradient and cross-gradient perimeter. EPA also received many 
comments arguing that the minimum requirements were overly 
prescriptive, and that the final rule should instead allow a 
professional engineer or hydrologist to design ``an alternative, but 
equally effective, groundwater monitoring program.'' The majority of 
comments on groundwater monitoring systems requested that EPA not 
promulgate requirements that would be incompatible with state 
requirements.
    The final rule provisions are fundamentally the same as those in 
the proposal, although EPA has also added language to the regulations 
to better clarify how the requirements in the various sections 
collectively operate. The final rule establishes a general performance 
standard that all groundwater monitoring systems must meet: All 
groundwater monitoring systems must consist of a sufficient number of 
appropriately located wells (at least one upgradient and three 
downgradient wells) in order to yield groundwater samples from the 
uppermost aquifer that represent the quality of background groundwater 
and the quality of groundwater passing the waste boundary. This is the 
same performance standard included in the proposed rule. The objective 
of a groundwater monitoring system is to intercept groundwater to 
determine whether the groundwater has been contaminated by the CCR 
unit. Early contaminant detection is important to allow sufficient time 
for corrective measures to be developed and implemented before 
sensitive receptors are significantly affected. To accomplish this, the 
rule requires that wells be located to sample groundwater from the 
uppermost aquifer at the waste boundary. These requirements have been 
adopted without fundamental change from the proposal.
    Because hydrogeologic conditions vary so widely from one site to 
another, the rule does not prescribe the exact number, location and 
depth of monitoring wells needed to achieve the general performance 
standard. Rather, the rule requires the owner or operator to install a 
minimum of one upgradient and three downgradient wells, and any 
additional monitoring wells necessary to achieve the general 
performance standard of accurately representing the quality of the 
background groundwater and the groundwater passing the waste boundary. 
The number, spacing, and depths of the monitoring wells must be 
determined based on a thorough characterization of the site, including 
a number of specifically identified factors relating to the 
hydrogeology of the site (e.g., aquifer thickness, groundwater flow 
rates and direction). Further, any owner or operator who determines 
that the specified minimum number of wells is adequate must provide a 
factual justification for that decision. Factors that may substantiate 
a reduced density of groundwater monitoring wells includes simple 
geology (i.e., horizontal, thick, homogenous strata that are continuous 
across site, with no fractures, faults, folds, or solution channels), a 
flat and constant hydraulic gradient, uniform hydraulic conductivity, 
low seepage velocity, and high dispersivity potential.
    In essence, the rule establishes a presumption that the minimum of 
one upgradient and three downgradient wells is not sufficient, and 
requires the owner or operator to rebut that presumption in order to 
install only this minimum. This is fundamentally consistent with the 
proposed rule, which required the installation of a system that would 
achieve the general performance standard, as well as the

[[Page 21400]]

``minimum'' of one upgradient and three downgradient wells. The final 
regulation merely makes more explicit that both of these requirements 
must be met.
    EPA considered establishing a more prescriptive set of 
requirements, including a specified number, location, and design of 
monitoring wells, but because of the highly site specific nature of 
developing an adequate groundwater monitoring system, determined that 
it lacked sufficient information to be able to design a single 
groundwater monitoring system that would be nationally protective at 
all sites. A properly designed system must account for many variables, 
most of which are highly dependent on the individual characteristics of 
the unit and the facility site. Consequently, the final rule leaves the 
exact system design to be determined by those at the site, including a 
qualified professional engineer, who can tailor the design of the 
system to the unit and site conditions.
    Nevertheless, EPA is confident that the parameters laid out in the 
regulation will ensure that the design of groundwater monitoring 
systems at CCR facilities will be protective. As a practical matter, 
EPA expects that there will be few cases, if any, where four wells will 
be sufficient, given that this requirement was originally developed for 
hazardous waste management units that are typically much smaller than 
CCR units. As mentioned above, a small unit with simple geology, a flat 
and constant hydraulic gradient, uniform hydraulic conductivity, low 
seepage velocity, and high dispersivity potential would be the type of 
unit for which the minimum number of wells could be sufficient to meet 
the overall performance standard. Although EPA is finalizing a 
requirement for one upgradient and three downgradient wells as a 
regulatory minimum, the Agency expects large CCR units to have many 
more wells because most CCR sites have hydrologic settings that are too 
complex for the regulatory minimum to be adequate. Facilities with 
large CCR units could have as many as thirty or more downgradient 
wells. This is because the placement and spacing of detection 
monitoring wells along the downgradient perimeter of the CCR unit must 
be based on the abundance, extent, and physical/chemical 
characteristics of the potential contaminant pathways. All potential 
pathways need to be monitored.
    Therefore, even though EPA is not requiring a specific number of 
wells, the Agency is confident that the combination of the requirements 
will ensure that protective groundwater monitoring systems will be 
installed. The owner or operator is required to install a sufficient 
number of wells to meet the performance standard in Sec.  257.91(a)(1) 
and (2), provide a justification if they determine the required minimum 
is adequate, and have a qualified professional engineer certify that 
their groundwater monitoring system has been designed and constructed 
to ensure that the groundwater monitoring will meet this performance 
standard--i.e., accurately represent the quality of groundwater that 
has not been affected by leakage from any CCR unit--that is, 
groundwater from background wells and the quality of groundwater 
passing the waste boundary.
    The final rule establishes certain parameters regarding the 
location of the wells. Upgradient background wells must be located 
beyond the upgradient extent of potential contamination. However, 
groundwater quality in areas where the geology is complex can be 
difficult to characterize. If the facility is new, groundwater samples 
collected from both upgradient and downgradient locations prior to 
waste disposal can be used to establish background water quality. 
Downgradient wells to monitor for any contaminants leaking into the 
groundwater must be located at the hydraulically downgradient perimeter 
(i.e., the edge) of the CCR unit or at the closest practical distance 
from this location.
    Determining background groundwater quality by sampling wells that 
are not hydraulically upgradient may be necessary where hydrogeologic 
conditions do not allow the owner or operator to determine which wells 
are hydraulically upgradient (e.g., floodplains, where nearby surface 
water can influence groundwater). In such cases, the rule allows the 
owner or operator to establish groundwater quality at existing units by 
locating wells that are not upgradient under certain conditions (Sec.  
257.91(a)(1)). This provision may be used when hydrogeologic conditions 
do not allow the owner or operator to determine which wells are 
hydraulically upgradient and when sampling at other wells will provide 
data establishing background groundwater quality that is equally or 
more representative than that provided by upgradient wells. These 
conditions could include one or more of the following:
     The facility is located above an aquifer in which 
groundwater flow directions change seasonally.
     The facility is located near production wells that 
influence the direction of groundwater flow.
     Upgradient groundwater quality is affected by a source of 
contamination other than the CCR unit.
     The proposed or existing CCR unit overlies a groundwater 
divide or local source of recharge.
     Geologic units present at downgradient locations are 
absent at upgradient locations.
     Karst terrain or fault zones modify flow.
     Nearby surface water (e.g., rivers) influences groundwater 
flow directions.
    Additionally, there is nothing in the rule that would prevent the 
owner or operator from monitoring multiple aquifers in addition to the 
uppermost significant aquifer. Certain site conditions warrant more 
extensive monitoring requirements, as discussed in ``Technical Manual 
Solid Waste Disposal Facility Criteria'', EPA530-R-93-017, USEPA, 
November, 1993, Chapter 5, Subpart E, Ground-Water Monitoring and 
Corrective Action.
    Each CCR unit must have its own groundwater monitoring system, 
unless the owner or operator chooses to install a multiunit groundwater 
monitoring system. The final rule specifies that if a multiunit system 
is installed, it must be based on the consideration of several factors, 
including the number, spacing, and orientation of the CCR units, the 
hydrogeologic setting, the site history and the engineering design of 
the CCR units. A multiunit groundwater monitoring system must be 
equally capable of detecting background and groundwater contamination 
at the waste boundary as an individual monitoring system. This 
documentation must be certified by a qualified professional engineer. 
Whether a single or multi-unit system has been installed, the 
monitoring wells must be cased in a manner maintaining the integrity of 
the borehole and must be maintained so as to meet design 
specifications. Both of these provisions have been adopted from the 
proposal without revision.
3. Sampling and Analysis Requirements
    EPA received comment on several aspects of its proposed 
requirements for conducting groundwater sampling and analyses. 
Specifically mentioned here, commenters raised concern about the number 
of samples required to establish background concentrations and about 
the statistical test methodologies specified in the proposal. As 
discussed below, EPA has modified the rule to account for the issues 
raised by these commenters. The sampling and analysis requirements in 
the final rule have

[[Page 21401]]

otherwise been adopted from the proposed rule with only minor 
clarifications.
    The rule provides procedures for sampling monitoring wells and 
methods for the statistical analysis of groundwater monitoring of 
appendix III (detection monitoring) and appendix IV (assessment 
monitoring) constituents that may be released from CCR units. The 
sampling and analysis program must include procedures and documentation 
for sample collection (including the frequency, water level 
measurements, well purging, field analyses, and sample withdrawal and 
collection); sample preservation and handling (including sample 
containers, sample preservation, sample storage and shipment); chain of 
custody control; analytical procedures (appropriate methods can be 
found in ``Test Methods for Evaluating Solid Waste, Physical/Chemical 
Methods,'' SW-846 (USEPA, 1986), http://www.epa.gov/waste/hazard/testmethods/sw846/online/index.htm); and quality assurance/quality 
control. More information and guidance can be found in ``Technical 
Manual Solid Waste Disposal Facility Criteria,'' EPA530-R-93-017, 
USEPA, November, 1993, Chapter 5, Subpart E, Ground-Water Monitoring 
and Corrective Action, as well as the ``Unified Guidance Document: 
Statistical Analysis of Groundwater Monitoring Data at RCRA 
Facilities,'' March 2009, EPA 530/R-09-007.
    Similar to the approach used in designing a groundwater a number of 
system, the final rule adopts a combination of a general performance 
standard for groundwater sampling and analytical methods, along with 
particular technical specifications that must be met. The general 
performance standard requires that the method used must accurately 
measure hazardous constituents and other monitoring parameters. In 
addition, the rule specifies that groundwater elevations must be 
measured in each monitoring well immediately prior to sampling. Also, 
the rate and direction of the groundwater flow in the uppermost aquifer 
must be determined each time groundwater is sampled. Further, the rule 
specifies that the background groundwater quality must be established 
at a hydraulically upgradient well for each of the monitoring 
parameters or constituents required by the applicable groundwater 
monitoring program, except as provided in Sec.  257.91. The number of 
samples collected to establish groundwater quality data must be 
consistent with the appropriate statistical procedures determined for 
the specific statistical method chosen. The sampling must also be 
conducted to account for both seasonal and spatial variability in 
groundwater quality.
    To establish background levels, the proposed rule required that ``a 
minimum of four independent samples from each background and 
downgradient well must be collected and analyzed . . .'' 75 FR 35247-
35248 (proposed Sec. Sec.  257.93(f) and 257.94(b)). This is the same 
sampling protocol that EPA adopted for both the subtitle C and part 258 
groundwater monitoring requirements.
    EPA received comments criticizing this sampling protocol. Several 
commenters stated that more than the required four samples were needed 
in order to adequately represent background water quality and reduce 
the number of false negatives. For example, one commenter argued that 
EPA should require a minimum of one year of monthly monitoring of 
background concentrations to characterize fluctuations in parameters 
that will be evaluated statistically. The commenter claimed that this 
would also help to ensure that quarterly monitoring events are properly 
timed. Another comment stated that more data points and time were 
needed to ensure statistical confidence in the data. By contrast, 
another commenter objected to the requirement to obtain four 
independent samples, arguing that this requirement was unnecessary and 
should be deleted. The commenter argued that this requirement was 
inconsistent with EPA's Unified Guidance (EPA, 2009) for Statistical 
Analysis of Groundwater Monitoring Data at RCRA Facilities, which 
specifies that replicate samples (i.e., multiple samples from the same 
location during a given sampling event) should typically be limited to 
the collection of two samples from the same location, rather than four. 
Another commenter requested clarification on the number of samples 
required when establishing background levels that would serve as the 
point of comparison in determining whether a statistically significant 
increase over background levels had occurred.
    In response to these comments, EPA reviewed the available 
information to determine whether revisions to the proposed requirements 
were warranted.
    More recent information developed since the promulgation of the 
subtitle C and part 258 groundwater monitoring requirements indicates 
that statisticians now generally consider sample sizes of four or less 
to be insufficient for good statistical analysis because the 
observations are too few to adequately characterize the parameters of 
the population. Tests utilizing a small background sample size have low 
statistical performance in terms of power and per-test false positive 
rates. In 2009, EPA issued a guidance document that accounts for more 
recent scientific developments, ``Unified Guidance Document: 
Statistical Analysis of Groundwater Monitoring Data at RCRA 
Facilities,'' March 2009, EPA 530/R-09-007. This guidance recommends a 
minimum of eight to ten independent background observations be 
collected before performing the first statistical test. Sample sets of 
20 are considered optimal.
    RCRA regulations are predicated on having appropriate and 
representative background measurements. Samples should be tested 
against data which best represent current uncontaminated conditions. In 
addition, as discussed further in Unit VI.K.5 below, the detection of a 
statistically significant increase over background concentrations of 
the constituents of concern will have serious implications for unlined 
surface impoundments, as these units will be required to close whenever 
the facility makes such a finding. EPA is also cognizant of the 
significant differences between the subtitle C and part 258 regulations 
and the final regulations being promulgated for CCR units. Both the 
subtitle C and the part 258 MSWLF requirements are implemented under 
permit programs, under which regulatory authorities are specifically 
authorized to establish more stringent requirements to account for 
scientific advances (among other things). EPA expects that current 
permits generally specify a greater number of samples than the minimum 
laid out in the regulations (i.e., more than four) to determine 
background concentrations. And because of this it is less critical that 
those regulations (subtitle C and part 258) reflect the most current 
science. By contrast, as previously discussed, the provisions adopted 
under this rule are self-implementing, and will only be updated through 
a subsequent rulemaking. Accordingly, the Agency agrees with the 
comments that four samples would be insufficient and has amended the 
rule to require the owner or operator to collect, at a minimum, eight 
statistically independent and identically distributed (spatially 
invariant) samples from each well for each monitoring parameter. 
Although still a small sample size by statistical standards, eight 
independent observations allows for minimally acceptable estimates of 
variability and evaluation of trend and goodness-of fit. While more 
samples, including a full

[[Page 21402]]

year of background monitoring, would be scientifically ideal, the 
Agency selected eight samples by balancing the minimum number needed to 
ensure the scientific accuracy of the results against the need to 
expedite initiating the groundwater monitoring process of detecting 
exceedances, along with any necessary corrective action at these 
facilities.
    Background sampling (i.e., the requirement to collect eight 
statistically independent samples from each well) must be completed for 
all appendix III and IV constituents by the end of the 24 month period 
to begin implementation of the groundwater monitoring program.
    EPA has also revised the regulatory text relating to the number of 
samples that must be collected during subsequent sampling events after 
background concentrations have been established to clarify how the 
various provisions collectively operate. Consistent with the proposal, 
the final rule requires the owner or operator to collect and analyze 
the number of samples from each well necessary to be consistent with 
the statistical test selected under Sec.  257.93(e) and with the unique 
characteristics of the site, but at minimum, to collect at least one 
sample from each background and downgradient well. In cases where the 
groundwater is ``well-behaved'' one sample from each compliance well 
could be all that the owner or operator would need to conduct the 
necessary comparisons. But if statistical assumptions are not met 
(e.g., the observations are not statistically independent or background 
well data show trends) a comparison based on a single observation will 
not yield a significant result, and will likely result in a false 
positive. Further, detection monitoring tests, such as Student's t-
test, look at the difference between the sample means (e.g., upgradient 
vs downgradient) to determine when an observed difference should be 
considered more than a chance fluctuation. Every t-test assumes that 
the observations that make up each data group meet the requirements of 
statistical independence and stationarity. Therefore, the larger the 
sample size the more significant the result. In other words, a facility 
can choose to use only one observation (a group size of one), but the 
chances are good that the result derived would be non-significant, 
since there are many reasons sample means can vary. Consequently, it is 
likely to be in the facility's best interest to take more samples than 
the minimum, particularly in the early stages of monitoring. As 
monitoring continues, each successive sample will be added to the 
sampling data base, which will increase the confidence in the 
statistical analyses performed. Additional guidance on sample size can 
be found in the ``Unified Guidance Document: Statistical Analysis of 
Groundwater Monitoring Data at RCRA Facilities,'' March 2009, EPA 530/
R-09-007.
    The requirements for applying statistical procedures in the rule 
are the same as those included in the proposed rule, which were based 
on the statistical procedures used in the MSWLF regulations. The rule 
requires the owner or operator to select from among the listed 
statistical procedures based on a determination that the test is 
appropriate for evaluating groundwater at that site. The statistical 
method chosen must be appropriate for the distribution of chemical 
parameters or hazardous constituents. The rule has been revised to 
include the clarification that normal distributions of data values 
shall use parametric methods and non-normal distributions shall use 
non-parametric methods. The rule identifies four statistical 
procedures, along with an alternative procedure that must meet the 
performance standard of Sec.  257.93(g). The four specific statistical 
procedures provided in this final rule are: (1) A parametric analysis 
of variance followed by multiple comparison procedures to identify 
statistically significant evidence of contamination; (2) an analysis of 
variance based on ranks followed by multiple comparison procedures to 
identify statistically significant evidence of contamination; (3) a 
tolerance or prediction interval procedure; and (4) a control chart 
approach. The performance standard for the alternative method in 
subsection (g) is the same as the performance standard in the proposal, 
with minor revisions. EPA has deleted the performance standard 
``protect human health and the environment'' in subsections (3), (4) 
and (5). While that standard is perfectly appropriate in a context in 
which a regulatory authority will apply the standard, EPA is concerned 
that a qualified professional engineer will be unable to certify that 
any alternative statistical method meets that standard. EPA received 
comments from professional engineers raising concern about their 
ability to certify that many of the requirements in the proposed rule 
had been met without further specification or clarification. To address 
those concerns, in those three provisions EPA has substituted a more 
objective performance standard that more precisely defines the relevant 
issues to be considered. Specifically, the subsections now specify that 
those approaches must be ``at least as effective as any other approach 
in this section for evaluating groundwater.''
    The data objectives of the monitoring, in terms of the number of 
samples collected and the frequency of collection, must be consistent 
with the statistical method selected. Guidance on selecting a specific 
method is described in ``Unified Guidance Document: Statistical 
Analysis of Groundwater Monitoring Data at RCRA Facilities,'' March 
2009, EPA 530/R-09-007. The owner or operator must indicate in the 
operating record the statistical method that will be used in the 
analysis of groundwater monitoring results.
    The owner or operator must conduct the statistical comparisons 
between upgradient and downgradient wells within 90 days of completion 
of each sampling event and receipt of validated data. The statistical 
comparison must be conducted in order to determine if a statistically 
significant increase has occurred over background levels for each 
parameter or constituent required in the particular groundwater 
monitoring program that applies to the unit as determined under 
Sec. Sec.  257.94(a) or 257.95(a). This has been adopted without 
revision from the proposal.
    EPA is finalizing as proposed the prohibition in Sec.  257.93(b) on 
field filtering groundwater samples because filtration of samples for 
metals analyses will not provide accurate information concerning the 
mobility of metals contaminants, the primary objective of groundwater 
sampling. Metal contaminants may move through fractured and porous 
media not only as dissolved species, but also as precipitated phases, 
polymeric species, or adsorbed to particles of colloidal dimensions 
(<10 microns). For an assessment of mobility, all mobile species must 
be considered, including suspended or colloidal particles acting as 
absorbents for contaminants. Filtration of groundwater samples for 
metals analyses will not provide accurate information concerning the 
mobility of metal contaminants because some mobile species in solution 
are likely to be removed by filtration before chemical analysis. 
Significant underestimations of mobility may result if filters 
(typically 0.45 micron) are used to separate dissolved and particulate 
phases.
    In its approach to sampling EPA is specifying in the final rule 
that owners and operators use `total recoverable metals' concentrations 
in measuring groundwater quality. Measurement of total recoverable 
metals captures both the particulate fraction and dissolved

[[Page 21403]]

fraction of metals in natural waters. Exceedances of ambient water 
criteria on a total recoverable basis are an indication that metal 
loadings could be a stress to an ecosystem.
    One commenter argued that to prohibit field filtering would 
potentially bias the results artificially high, particularly at sites 
where low yielding formations or naturally high levels of turbidity in 
groundwater are encountered. However, high turbidity can also be the 
consequence of faulty well design and/or construction, which causes the 
introduction of foreign materials (high turbidity) through created 
fracture pathways. A properly designed well should allow for sufficient 
groundwater flow for sampling, minimize the passage of materials into 
the well, and exhibit sufficient structural integrity to prevent 
collapse of the intake structure. It is vital that the well provide a 
representative hydraulic connection to the geologic formation of 
interest. Otherwise the water chemistry information cannot be correctly 
interpreted in relation to groundwater flow or transport of chemical 
constituents.
    Sampling with no filtration means that increased importance is 
placed on proper well construction and purging sampling procedures to 
eliminate or minimize sources of sampling artifacts. There should be 
nothing in the well design that will lead to high levels of turbidity. 
Groundwater sampling should be conducted utilizing EPA protocol low 
stress (low-flow) purging and sampling methodology, including 
measurement and stabilization of key indicator parameters prior to 
sampling. For purposes of sampling, this final rule presumes that a 
properly constructed well is capable of yielding groundwater samples 
with low turbidity (<=5 Nephelometric Turbidity Units (NTU)), and by 
knowing the cause of turbidity the qualified professional engineer will 
be able to optimize well performance and reduce turbidity levels, 
eliminating the need for filtration.
    EPA is revising Sec.  257.93(i)(2) to specify a time period of 90 
days to determine if a statistically significant increase over 
background concentrations of one of more of the contaminants has been 
detected. As proposed, this section specified: ``Within a reasonable 
period of time after completing sampling and analysis, the owner or 
operator of the CCR landfill or surface impoundment must determine 
whether there has been a statistically significant increase over 
background at each monitoring well.'' Commenters pointed out that this 
section of the regulation was very vague, and potentially 
unenforceable. Several commenters suggested that once sampling and 
analysis had been completed, 90 days would be a reasonable amount of 
time to complete the statistical analysis to determine whether an 
exceedance had occurred. No commenter suggested a longer period of time 
was necessary and that timeframe is consistent with the Agency's 
experience of the timeframes necessary to complete such analyses. 
Accordingly, we have revised the provision to require the determination 
of a statistically significant increase to be made within 90 days of 
sampling and analysis.
4. Detection Monitoring Program
    With three exceptions, EPA is finalizing the regulatory provisions 
relating to detection monitoring as proposed. The three revisions are 
the appendix III list of monitoring parameters; the required number of 
samples to determine background concentrations; and the availability of 
an option to conduct detection monitoring on a less frequent basis due 
to a lack of groundwater.
    The detection monitoring phase of the groundwater monitoring 
program in this rule requires that the owners or operators of CCR units 
establish background concentrations for all monitoring parameters 
(appendix III and IV of part 257) and sample at least semiannually 
during the active life of the facility, closure, and post closure 
periods for a set of detection monitoring indicator parameters 
(appendix III of part 257).
    In response to comments, EPA has revised appendix III to delete 
conductivity and sulfide from the list of monitoring parameters and to 
add calcium. Thus, the list of parameters included on the detection 
monitoring list is boron, calcium, chloride, fluoride, pH, sulfate and 
total dissolved solids (TDS). The Agency has deleted conductivity from 
the detection monitoring program because it is merely a proxy for TDS, 
which is already included on the list of parameters to analyze during 
detection monitoring. The Agency has also deleted sulfide because it 
occurs in groundwater only under strongly reducing conditions, and such 
conditions are rather rare at CCR disposal facilities. Calcium is being 
added to appendix III because it is an indicator of the extent of 
leaching from fly ash and FGD gypsum and because of the strong 
demonstrated link between the leaching of calcium and arsenic, which is 
one of the primary risk drivers identified in the risk assessment.
    As discussed in the preceding section, in detection monitoring, a 
minimum of eight independent samples from each background and 
downgradient well must be collected and analyzed for the appendix III 
and IV parameters no later than 24 months from the effective date of 
the rule. During subsequent sampling events, at least one sample from 
each background and downgradient well must be collected and analyzed, 
although the total number of samples must be consistent with the 
statistical procedures selected and with the performance standard in 
Sec.  257.93(g). See discussion above in section 3. Sampling and 
Analysis Requirements.
    Under the proposed rule, monitoring would be required no less 
frequently than semiannually. In the final rule, semiannual sampling 
remains the general requirement; however, in response to comments, EPA 
has decided to include a provision that would allow an alternative 
sampling frequency if there is not adequate groundwater to flow to 
sample wells semiannually. Specifically, EPA received comment stating 
that there may be instances where there simply is not enough water 
available to collect and analyze on a semiannual basis, especially in 
western climates where the rate of groundwater recharge may be too slow 
or a lack of precipitation exists. The commenter also provided an 
example demonstrating that mining practices in adjacent areas can 
greatly alter the groundwater flow. Accordingly, EPA has included a 
provision to address the situations where there is insufficient 
groundwater available to collect and analyze samples around CCR units 
on a semiannual basis.
    An owner or operator seeking to establish an alternative frequency 
must demonstrate that less frequent monitoring is necessary based on 
the following three factors: (1) Lithology of the aquifer and the 
unsaturated zone; (2) hydraulic conductivity of the aquifer and the 
unsaturated zone; and (3) groundwater flow rates. In addition, the rule 
requires the owner or operator to demonstrate that any alternate 
sampling frequency would be no less effective in ensuring that any 
leakage from the CCR unit will be discovered within a timeframe that 
does not materially delay the initiation of any necessary remediation 
measures. The owner or operator must have a qualified professional 
engineer certify that the alternative (i.e., less frequent) monitoring 
will achieve this performance standard. The final rule also specifies 
that any alternate frequency during the active life (including closure) 
and the post-closure

[[Page 21404]]

care period shall be no less than annual. As noted, the owner or 
operator will bear the burden of justifying an alternate frequency 
under this regulation, and in any court proceeding brought to enforce 
these requirements. This means that any uncertainty or lack of 
information will be weighed against the entity seeking to justify the 
alternate frequency.
    Consistent with the proposed rule, if the owner or operator 
determines that there is a statistically significant increase (SSI) 
over background for one or more of the parameters listed in appendix 
III at any monitoring well at the waste boundary, the owner or operator 
must place a notice in the operating record and on the facility's 
internet site indicating which parameters have shown statistically 
significant changes from background levels and notify the State 
Director.
    The facility must also then establish an assessment monitoring 
program and begin monitoring within 90 days. The owner or operator has 
the opportunity to demonstrate that a source other than the CCR unit 
caused the statistically significant increase or that the statistically 
significant increase resulted from error in sampling, analysis, 
statistical evaluation or a natural variation in groundwater quality. 
Within 90 days, the owner or operator must prepare a report documenting 
this demonstration which must then be certified by a qualified 
professional engineer verifying the accuracy of the information in the 
report. If a successful demonstration is made within 90 days, the owner 
or operator may continue detection monitoring. If a successful 
demonstration is not made within 90 days, the owner or operator must 
initiate assessment monitoring.
    Commenters raised concern that 90 days would not be sufficient to 
complete all of the activities necessary to determine whether the 
detection of an SSI was from another source than the CCR unit or was 
based on inaccurate results. The Agency recognizes that in some 
circumstances it could take more than 90 days to resample and have 
laboratories conduct new analyses, or to conduct field investigations 
to determine that another source is causing the contamination. As a 
result, Sec.  257.94(e)(3) does not place an ultimate time limit for 
owners and operators to complete the demonstration. However, if after 
90 days the owner or operator has not made a successful demonstration, 
(s)he must begin an assessment monitoring program. At this stage, there 
is evidence to indicate that a release has occurred from the CCR unit, 
and while EPA agrees that the facility may want to confirm that the 
information is accurate, it is critical that the facility not delay 
indefinitely the more targeted monitoring to determine whether a 
constituent of concern is contaminating groundwater. It would not be 
consistent with the statutory standard to allow a facility unlimited 
time to delay taking reasonable steps to assess, and if necessary, 
address potential contamination by continuing to resample until they 
obtain a ``better'' answer. Moreover, initiation of an assessment 
monitoring program does not involve an irretrievable commitment of 
resources or even a significant investment by the facility, but only 
requires the facility to begin more targeted sampling for constituents 
of concern. This represents a reasonable first step to address a 
potential threat to groundwater. This requirement is also in the MSWLF 
part 258 regulations. For more information see 56 FR 51078 (October 9, 
1991).
    Subsequent to initiating the assessment monitoring program, if an 
owner or operator demonstrates that the statistically significant 
increase resulted from an error in sampling, analysis, statistical 
evaluation, or natural variation in groundwater quality, or was caused 
by a source other than the CCR unit, the owner or operator may cease 
assessment monitoring and return to detection monitoring. If the 
demonstration is successful, the owner or operator must have the 
demonstration certified by a qualified professional engineer, and is 
required by Sec.  257.94(e)(3) to place a notice in the operating 
record, and on publicly accessible Internet site and send a copy of the 
report to the State Director.
5. Assessment Monitoring Program
    EPA is adopting an assessment monitoring program that is largely 
identical to the program laid out in the proposal. However, as 
discussed in more detail below, some revisions have been made; some 
were made in response to comments, but most are conforming changes made 
to be consistent with changes adopted in other provisions, such as the 
detection monitoring program described previously.
    Consistent with the proposed rule, if any of the detection 
monitoring parameters are detected at a statistically significant level 
over the established background concentrations, the owner or operator 
must proceed to the next step, assessment monitoring. Assessment 
monitoring requires annual sampling and analysis for the full list of 
constituents included in appendix IV. The number and frequency of 
samples required for assessment monitoring are the same as those 
established for detection monitoring. See discussion above in 3. 
Sampling and Analysis Requirements.
    EPA has also revised the list of constituents in appendix IV by 
deleting the following constituents and parameters: Aluminum, boron, 
chloride, copper, iron, manganese, pH, sulfate, sulfide, and TDS; and 
adding the following constituents: Cobalt, lithium, and radium 226 and 
228 combined. The following constituents and parameters are being 
removed from appendix IV because they are on appendix III and therefore 
will continue to be monitored throughout assessment monitoring: Boron, 
chloride, pH, sulfate and TDS. Although fluoride is on appendix III, we 
are also retaining it on appendix IV because it does have an MCL and 
was found to pose risks in the 2014 risk assessment, and therefore is 
appropriately considered to be a constituent that is relevant for 
purposes of corrective action. Aluminum, copper, iron, manganese, and 
sulfide have been removed because they lack maximum contaminant levels 
(MCLs) and were not shown to be constituents of concern based on either 
the risk assessment conducted for this rule or the damage cases (see 
Units X and XI of this document). Cobalt has been added to appendix IV 
because cobalt was found to be a risk driver in the 2014 risk 
assessment, based on certain waste management disposal practices that 
lead to highly acidic wastes conditions. Lithium is being added to 
appendix IV because it has been detected in several proven and 
potential damage cases at levels exceeding EPA's Regional Screening 
Level (RSL) of soil to groundwater and has been determined as 
potentially toxic if consumed concurrently with certain drug 
types.\117\ Radium 226 and 228 combined (the sum of the radioactive 
isotopes radium-226 and radium-228) is being added because there is 
evidence from several damage cases of exceedances of gross alpha, 
indicating that radium from the disposal of CCR may be problematic. 
Appendix IV now contains antimony, arsenic, barium, beryllium, cadmium, 
chromium, cobalt, fluoride, lead, lithium, mercury, molybdenum,

[[Page 21405]]

selenium, thallium and radium 226 and 228 combined.
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    \117\ EPA's Regional Screening Level (RSL) Soil to Groundwater 
Supporting Table (TR = 1E-6, HQ = 1) May 2014/Mid-atlantic Risk 
assessment: http://www.epa.gov/reg3hwmd/risk/human/rb-concentration_table/Generic_Tables/index.htm; and Health 
Consultation: Chesapeake ATGAS 2H Well Site Leroy Hill Road, Leroy, 
Leroy Township, Bradford County, Pennsylvania, October 29, 2013. 
U.S. Department of Health and Human Services, Agency for Toxic 
Substances and Disease Registry Division of Community Health 
Investigations Atlanta, Georgia. http://www.atsdr.cdc.gov/.
---------------------------------------------------------------------------

    If any appendix IV constituents are detected in any appendix IV 
analyses, the owner or operator must notify the State Director and 
continue to monitor, at least semiannually, for both the specific 
constituents in appendix IV that were detected and all parameters in 
appendix III. EPA has decided to also include a provision to allow an 
alternative sampling frequency if there is not adequate groundwater to 
flow to sample wells semiannually, consistent with the revised 
provision adopted for the detection monitoring program. If the owner or 
operator demonstrates at any time during assessment monitoring that all 
of the detected appendix III and IV constituents are at or below 
background values for two consecutive sampling events, (s)he must 
notify the state and may return to detection monitoring. In general, 
EPA expects that appendix III constituents are unlikely to remain 
elevated once measures have been taken to address the release of the 
detected appendix IV constituents. But should appendix III constituent 
levels remain elevated, detection monitoring continues to be necessary 
to determine whether another source of contamination is present.
    After obtaining the sampling results the owner or operator must 
place a notice in the operating record and on the facility's internet 
site indicating which appendix IV constituents have been detected and 
notify the State Director. Within 90 days and on at least a semiannual 
basis thereafter, the owner or operator must resample all wells, 
conduct analyses for all parameters in appendix III and for those 
constituents in appendix IV that were detected in the initial 
assessment monitoring sampling event. The results of this resampling 
must be placed in the owner or operator's operating record, as well as 
its publicly accessible internet site. The results of the resampling 
must also be sent to the State Director. These provisions have been 
adopted without change from the proposal.
    For each appendix IV constituent that is detected, a groundwater 
protection standard must be set. The groundwater protection standards 
must be the MCL or the background concentration level for the detected 
constituent, whichever is higher. If there is no MCL promulgated for a 
detected constituent, then the groundwater protection standard must be 
set at background. The proposed rule would have allowed the owner or 
operator to establish an alternative groundwater protection standard 
for constituents for which MCLs have not been established provided that 
the alternative groundwater protection standard has been certified by 
an independent registered professional engineer and the state has been 
notified that the alternative groundwater protection standard has been 
placed in the operating record and on the owner's or operator's 
publicly accessible internet site. This provision had been adopted from 
the part 258 regulations, but was determined to be inappropriate in a 
self-implementing rule, as it was unlikely that a facility would have 
the scientific expertise necessary to conduct a risk assessment, and 
was too susceptible to potential abuse. Additionally, numerous comments 
were received suggesting that only those constituents with MCLs be 
included in appendix IV. The commenters were concerned that only MCLs 
are enforceable. With the exception of cobalt, lead, lithium and 
molybdenum (included on appendix IV because of their relevance in the 
risk assessment and damage cases), all appendix IV constituents have an 
MCL. In the proposed rule, as stated above, owner or operators were 
allowed to establish certain types of alternative groundwater 
protection standards. In the final rule, if a constituent has no MCL 
(i.e., cobalt, lead, lithium and molybdenum), their groundwater 
protection standards will be their background levels. These background 
standards are sufficiently precise that they are enforceable.
    The owner or operator must compare the levels of any detected 
appendix IV constituents to the appropriate groundwater protection 
standard. If the concentrations of all appendix IV constituents are 
shown to be at or below background values for two consecutive sampling 
events using the statistical procedures required by Sec.  257.93, the 
owner or operator of the CCR disposal facility must place that 
information in the operating record and on the facility's publicly 
accessible internet site and notify the State Director. The owner or 
operator may then return to detection monitoring.
    If the concentrations of any appendix III or IV constituents are 
above background values, but all concentrations are determined to be 
below the groundwater protection standard using the statistical 
procedures required by this rule, the owner or operator must continue 
assessment monitoring program.
    If, however, the monitoring indicates a statistically significant 
increase for any appendix IV constituent over the groundwater 
protection standard, the owner or operator is required to notify the 
State Director and local officials of this finding and place a notice 
in the operating record and on the owner or operator's publicly 
accessible internet site.
    The owner or operator also must characterize the nature and extent 
of the release. As part of characterizing the nature and extent of the 
release, the owner or operator must install additional wells, as 
necessary to define the contaminant plume(s) and collect data on the 
nature and estimated quantity of the material released. Adequate 
characterization of the release is critical in designing and 
effectively implementing a protective corrective action program if 
groundwater remediation is necessary. The purpose of these additional 
wells is to delineate the contaminant plume boundary and to eventually 
demonstrate the effectiveness of corrective action in meeting the 
groundwater protection standard.
    Because the requirements for additional monitoring are entirely 
specific to the site conditions and the size and nature of the release, 
the Agency is not able to set requirements that precisely specify the 
location or the number of additional wells that must be installed. 
Instead EPA has adopted an approach that corresponds to the approach to 
designing the original groundwater monitoring system under Sec.  
257.91. The regulations establish a general performance standard 
(``install additional wells as necessary to define the contaminant 
plume'') and specify a true minimum of installing at least one well at 
the facility boundary in the direction of contaminant migration in 
order to ascertain whether the contaminants have migrated past the 
facility boundary. The regulations also establish a rebuttable 
presumption that this minimum is insufficient, requiring the owner or 
operator to justify a decision to install only this minimum. The 
requirement to justify the decision to only install the minimum number 
of additional wells is a revision from the proposal that has been 
adopted to be consistent with the Agency's overall approach to 
developing an effective groundwater monitoring system.
    The Agency has also added some clarification to the proposed 
requirement to characterize the nature and extent of the release, by 
requiring the owner or operator to collect data on the nature and 
estimated quantity of material released, including specific information 
on the constituents listed in appendix IV and the levels at which they 
are present in the material released. This information will be 
necessary to help the owner or operator characterize the release and 
assist in ultimately deciding on a remedy.

[[Page 21406]]

    If contamination has migrated off-site, the owner or operator must 
notify individuals who own land or reside on land overlying the plume.
    In addition to characterizing the nature and extent of the release, 
the owner or operator must initiate an assessment of corrective 
measures within 90 days of finding a statistically significant increase 
over background concentrations, and select the appropriate remedy. 
During this phase, the owner or operator is required to continue at 
least semiannual monitoring (or an alternative frequency, no less than 
annually) for all appendix III constituents and for those appendix IV 
constituents exceeding the groundwater protection standard. To be 
consistent with the provisions in detection monitoring, EPA has 
included a provision that would allow the owner or operator to 
demonstrate that a source other than their CCR unit caused the 
contamination or that the statistically significant increase above 
groundwater protection standards resulted from error in sampling, 
analysis, statistical evaluation, or natural variation in groundwater 
quality. This alternative option will not delay compliance with the 
next phase of the groundwater monitoring and corrective action program. 
Thus, until such a demonstration is made, the owner or operator must 
comply with the other requirements of this section, including 
initiating the assessment of corrective measures. At this stage, the 
evidence that the CCR unit is leaking is stronger, and the owner or 
operator has previously had the opportunity to demonstrate that the 
finding was made in error under the detection monitoring program, so no 
further delay in initiating measures to address any groundwater 
contamination is warranted.
    Another change since the proposal is that in addition to complying 
with all of the corrective action requirements--i.e., initiating an 
assessment of corrective measures, followed by selection of a remedy 
and implementation of a corrective action program--if the unit is an 
unlined surface impoundment, it must either retrofit or initiate 
closure. Further, where the facility has chosen to install a multi-unit 
groundwater monitoring system, the detection of an SSI of an appendix 
IV constituent would trigger the corrective action and closure (or 
retrofit) of all of the unlined surface impoundments covered by that 
monitoring system, as there will be no way to isolate a particular 
unlined unit as the source of the contamination. These requirements are 
discussed in more detail in the Closure section.
6. Assessment of Corrective Measures
    This section of the regulations also largely mirrors the analogous 
provisions in the proposed rule. EPA added some language to reflect 
that this section is not limited to the remediation of groundwater from 
a leaking CCR unit but will also apply to contamination caused by any 
kind of release from a CCR unit. EPA also made some minor revisions in 
response to comments, and some editorial changes to conform this 
provision to changes made in other sections of the rule.
    Consistent with the proposal, Sec.  257.96(a) specifies that the 
assessment of corrective measures must be initiated within 90 days of 
detecting a statistically significant increase of any of the 
constituents listed in appendix IV, at a level exceeding the 
groundwater protection standard(s), or of otherwise documenting a 
release of contaminants from the CCR unit. The regulation also requires 
the assessment of corrective measures to be completed in 90 days of 
such a finding, but in response to comments, EPA is adopting a 
provision that will allow for a single 60 day extension. Multiple 
commenters argued that 90 days was not adequate to complete the 
assessment of corrective measures. Commenters stated that for 
situations with complex hydrogeology, additional studies and sampling 
may be required in order to assess potential contributing offsite 
sources, background levels, and possible remedies. They stated that 
identification of remedy alternatives, collection and analysis of data 
used to evaluate remedy alternatives, and discussions with vendors/
contractors regarding availability of labor and materials are all 
critical steps in the remedy selection process. As explained in the 
``Technical Manual Solid Waste Disposal Facility Criteria,'' EPA530-R-
93-017, USEPA, November, 1993, Chapter 5, Subpart E, Ground-Water 
Monitoring and Corrective Action, the owner or operator will need to: 
(1) Identify and remediate the source of contamination; and (2) 
identify and remediate the known contamination. The factors that must 
be considered in assessing corrective measures include source 
evaluation, plume delineation, groundwater assessment and source 
control. Based on the comments received, as well as the Agency's own 
experience, EPA recognizes that there may be complex situations that 
require more time to develop a careful and well-thought out corrective 
measures assessment. Therefore, the final rule has been modified to 
allow up to an additional 60 days to complete the assessment of 
corrective measures, provided that a qualified professional engineer 
certifies that the additional time is necessary. The initial 90 days 
plus the additional 60 days, which is within the range of time 
suggested by the commenters, would provide the owner or operator up to 
150 days to complete the corrective measures assessment, which EPA 
expects will be sufficient. The certification must be placed in the 
operating record, on the owner's or operator's publicly accessible 
internet site and submitted to the proper state official.
    The rule requires the owner or operator to assess the effectiveness 
of potential remedies in meeting the objectives of Sec.  257.97 by 
addressing at least: (1) Performance, reliability, ease of 
implementation and potential impacts; (2) time requirements; and (3) 
institutional requirements. The proposed rule also included 
consideration of the costs of remedy implementation. However, that 
language came directly from the MSWLF rule in part 258. Because 
Congress did not authorize the consideration of costs in establishing 
minimum national standards under RCRA section 4004(a), we have removed 
this factor. In evaluating the performance, reliability, ease of 
implementation, and potential impacts of each remedy, the owner or 
operator should evaluate whether specific remedial technologies are 
appropriate to the problem and the ability of those technologies to 
achieve the groundwater protection standards. Analysis of a remedy's 
reliability should include an assessment of the effectiveness of the 
remedy in controlling the source of the release and its long-term 
reliability. Source control measures need to be evaluated to limit the 
migration of the plume, and to ensure an effective remedy. The 
regulation does not limit the definition of source control to exclude 
any specific type of measure to achieve this. Remedies must control the 
source of the contamination to reduce or eliminate further releases by 
identifying and locating the cause of the release. Source control 
measures may include the following: Modifying the operational 
procedures (e.g., banning waste disposal); undertaking more extensive 
and effective maintenance activities (e.g., excavate waste to repair a 
liner failure); or, in extreme cases, excavation of deposited wastes 
for treatment and/or offsite disposal. Construction and operation 
requirements also should be evaluated. The analysis of the timing of 
potential remedies should include an evaluation of construction, start-
up, and

[[Page 21407]]

completion time. Timing is particularly important if contamination has 
migrated off-site. Institutional requirements such as local permit or 
public health requirements may affect implementation of the remedies 
evaluated and should be assessed by the owner or operator.
    The proposed rule included a provision that would allow an owner or 
operator to determine that compliance cannot be reasonably achieved 
with any currently available methods. This has been deleted from the 
final rule. The Agency determined that without state oversight or a 
permitting program, that provision was potentially subject to abuse and 
thus, inappropriate to include in a self-implementing rule.
    As part of evaluating potential remedies, the owner or operator 
must hold a public meeting to discuss the remedies under consideration 
(prior to selecting a final remedy). Once the owner or operator has 
selected a remedy, he must place a description of the selected remedy 
in the operating record, on the owner or operator's publicly accessible 
internet site and notify the State Director.
7. Selection of Remedy
    This section of the final rule has been adopted with only minor 
changes from the proposal. As in the prior section, EPA has revised 
certain provision to reflect that this section will also apply to the 
cleanup of contamination caused by a release from a CCR unit. EPA also 
deleted a provision that had been adopted from the part 258 
regulations, but that was determined to be inappropriate in a self-
implementing rule as it was too susceptible to potential abuse.
    Based on the results of the corrective measures assessment 
conducted, the owner or operator must select a remedy. The selected 
remedy must attain all of the performance standards listed in 
subsection (b). Specifically, the remedy must protect human health and 
the environment, attain the groundwater protection standards, control 
the sources of releases so as to reduce or eliminate, to the maximum 
extent practicable, further releases of appendix IV constituents into 
the environment, and comply with any relevant standards for management 
of wastes generated as a result of the remedial activities. EPA 
included an additional criterion more directly related to remediation 
of contamination associated with a release, such as from a collapse or 
structural failure of a CCR unit, which requires the remedy to ``remove 
from the environment as much of the contaminated material that was 
released from the CCR unit as is feasible, taking into account factors 
such as avoiding the inappropriate disturbance of sensitive 
ecosystems.'' Together, these criteria reflect the major technical 
components of any kind of clean up remedy.
    The rule also specifies decision criteria to be considered by the 
owner or operator in selecting the most appropriate remedy. These 
include: (1) Long and short term effectiveness, and degree of certainty 
of success; (2) effectiveness of remedy in controlling the source to 
reduce further releases; (3) ease or difficulty of implementation; and 
(4) community concerns. Additionally, the rule requires the owner or 
operator to specify a schedule for implementing and completing the 
remedial activities. The rule requires the owner or operator to set the 
schedule because it is impossible for EPA to establish a single 
schedule appropriate for all possible situations; the schedule will 
necessarily depend on the nature and size of the contamination, among 
other factors. The rule outlines six factors to be considered in 
establishing a schedule for completing remedies (Sec. Sec.  
257.97(d)(1-6)). These factors are: (1) Extent and nature of 
contamination; (2) reasonable probabilities of remedial technologies in 
achieving compliance with the groundwater protection standards; (3) 
availability of treatment or disposal capacity for CCR managed during 
implementation of the remedy; (4) potential risks to human health and 
the environment; (5) resource value of the aquifer; and (6) other 
relevant factors. EPA had included one additional factor in the 
proposal: ``The desirability of utilizing technologies that are not 
currently available, but which may offer significant advantages over 
already available technologies in terms of effectiveness, reliability, 
safety, or ability to achieve remedial objectives.'' EPA considered 
that this provision, which could be used to justify delaying 
remediation measures, was potentially subject to abuse and thus, 
inappropriate to be included in a self-implementing rule.
    For similar reasons, EPA deleted the provisions in the proposal, 
subsections (e) and (f) that would authorize a facility to determine 
that remediation of a release is not necessary. These sections which 
came from the MSWLF rule in part 258 are appropriate where there is 
state oversight. The preamble to the final MSWLF rule specifically 
discusses situations in which an approved state may decide not to 
require cleanup of hazardous constituents released to groundwater from 
a MSWLF (see 56 FR 51090). However, there is no similar guarantee that 
an individual facility will act in the public interest.
8. Implementation of the Corrective Action Program
    The proposed rule required the owner or operator to include a 
schedule for initiating the remedial activities in the schedule for 
implementing the remedy (Sec.  257.97(d)). The Agency understands that 
selecting a remedy is closely related to the assessment process and 
cannot be accomplished unless a sufficiently thorough evaluation of 
alternatives has been completed. The process of documenting the 
rationale for selecting a remedy requires that a report be placed in 
the operating record that clearly defines the corrective action 
objectives and demonstrates why the selected remedy is anticipated to 
meet those objectives. The report must identify how the remedy will be 
protective of human health and the environment, attain the groundwater 
protection standards (either background or MCLs), attain source control 
objectives, and comply with waste management standards.
    The selection of a remedy also involves a public meeting with 
interested parties before finally selecting a remedy. For these 
reasons, the Agency is not establishing a deadline for completing the 
remedy selection process, but rather expects it to be completed as soon 
as practicable. Once the assessment of corrective measures has been 
completed within the timeframe specified in this rule, and the public 
meeting has occurred, the facility owner or operator must select a 
remedy and begin implementing that remedy as soon as is practicable. It 
is vitally important that the facility selects a remedy as soon as 
practicable and begins designing and implementing that remedy, so that 
releases to groundwater are addressed without unnecessary delay. EPA 
understands that there are a variety of activities that may be 
necessary in order to select the appropriate remedy (e.g., discussions 
with affected citizens, state and local governments; conducting on-site 
studies or pilot projects); and, once selected, to implement the remedy 
(e.g., securing on-site utilities if needed, obtaining any necessary 
permits, etc.). That is why EPA does not find it appropriate to set 
specific timeframes for selecting the remedy or to begin implementing 
the selected remedy. However, in order to ensure that the community is 
kept informed as to the progress of selecting and implementing the 
remedy, EPA is requiring that the facility owner or operator, on a 
semiannual basis, post status reports/updates on their progress

[[Page 21408]]

to their publicly accessible internet site and submit these to the 
state.\118\
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    \118\ As evidenced in 42 U.S.C. 6971(f), Congress intended that 
the OSHA be able to enforce its regulations to protect workers 
exposed to hazardous waste and that EPA and OSHA would work together 
to ensure that. EPA is clarifying that it intends that the CCR 
disposal rule not preempt applicable OSHA standards designed to 
protect workers exposed to CCRs; thus EPA's final rule on CCR 
disposal will apply in addition to any applicable OSHA standards. 
The Agency has added specific regulatory language in this section to 
address this intent.
---------------------------------------------------------------------------

    However, the Agency has concluded that it is reasonable to require 
that once a remedy has been chosen, the owner or operator of the CCR 
unit must begin to implement that remedy within a specified period of 
time. Consistent with the timeframes throughout this section, the final 
rule requires that within 90 days of selecting a remedy, the owner or 
operator must have initiated corrective measures, including any interim 
measures determined to be appropriate, and have established a 
corrective action groundwater monitoring program (and begin following 
it). (Sec.  257.98). This is a reasonable timeframe in which to begin 
these activities based on EPA's long experience in conducting and 
overseeing cleanup activities.
    The remedy would be considered complete when the owner or operator 
demonstrates compliance with the groundwater protection standards for a 
period of three consecutive years, and all other actions required to 
meet the performance standards in Sec.  257.97(b) have been satisfied 
(e.g., source control). The owner or operator must obtain certification 
that the remedy is complete from a qualified professional engineer, and 
must notify the State Director. The certification must also be placed 
in the operating record and on the owner or operator's publicly 
accessible Internet site.
    The Agency deleted the provision that allows an owner or operator 
to determine that compliance cannot be reasonably achieved with any 
currently available methods. The Agency determined that without state 
oversight or a permitting program, that provision was potentially 
subject to abuse and thus, inappropriate to be included in a self-
implementing rule.
9. Timing Overview
    The groundwater monitoring regulations require that the owner or 
operator of existing CCR units must comply with Sec.  257.90-Sec.  
257.94 within 30 months of the date of publication of the rule. 
Essentially, that means that by the end of 30 months, the owner or 
operator must (1) install the groundwater monitoring system; (2) 
document the sampling and analysis procedures; (3) establish which 
statistical tests will be used to determine exceedances; (4) sample all 
wells to have a minimum of 8 samples for all appendix III and IV 
parameters; and (5) determine if there is a statistically significant 
exceedance of any appendix III parameter, which would trigger 
assessment monitoring.
    New CCR units must comply with Sec. Sec.  257.90-257.93, including 
the requirement under Sec.  257.94(b) to collect and analyze eight 
independent samples from each well for the parameters listed in 
appendix III and IV to this part to determine background levels for all 
appendix III and IV constituents, before commencing operation. 
Essentially, that means that before receiving CCR waste, the owner or 
operator must (1) install the groundwater monitoring system; (2) 
document the sampling and analysis procedures; (3) establish which 
statistical tests will be used to determine exceedances; and (4) sample 
all wells to have a minimum of eight samples for all appendix III and 
IV parameters.
    If assessment monitoring is triggered, within three months the 
owner or operator must sample all wells for all appendix IV 
constituents (minimum of one sample) and resample (minimum of one 
sample) all wells for all appendix III parameters and those appendix IV 
constituents that were detected in the first round of sampling. The 
owner or operator could also simultaneously use this three month 
timeframe to demonstrate that the statistically significant increase 
found in detection monitoring was due to another source or sampling and 
analysis error. While conducting assessment monitoring, the owner or 
operator must continue sampling for all appendix III constituents and 
any appendix IV detected constituents semiannually. The owner or 
operator must sample for all appendix IV constituents annually.
    The owner or operator must also establish groundwater protection 
standards (MCL or background levels) for all appendix IV constituents 
detected during sampling.
    If one or more appendix IV constituents are detected at 
statistically significant levels above the groundwater protection 
standards established, or a release from a CCR unit has been detected, 
corrective action is triggered. The owner or operator must characterize 
the nature and extent of the release by installing additional 
monitoring wells, collecting data on the quantity and concentration 
levels of regulated constituents in the released material, sampling and 
notifying the State Director, local government officials, and any 
persons who own land or reside on the land that overlies the plume if 
the plume has migrated off site. The owner or operator must also place 
the notification in their operating record and on their publicly 
accessible Internet site.
    If corrective action is triggered, within three months the owner or 
operator must initiate an assessment of corrective measures. If the CCR 
unit is an unlined surface impoundment, the unit must stop receiving 
CCR and non-CCR wastes and initiate closure of the unit or begin to 
retrofit the unit within six months. The owner or operator could also 
simultaneously use these three months to initiate an assessment of 
corrective measures to demonstrate that the statistically significant 
increase found during assessment monitoring was due to another source 
or sampling and analysis error.
    The assessment of corrective measures must be completed in three 
months, with the possibility of an additional two months if the owner 
or operator demonstrates the need for additional time. The owner or 
operator must continue assessment monitoring and provide notification 
of the corrective measures assessment to the State Director and place 
the assessment in the operating record and on the owner's or operator's 
publicly accessible Internet site. The owner or operator also must 
discuss the results of the corrective measures assessment at least one 
month prior to selection of remedy in a public meeting.
    Within three months of selecting a remedy, the owner or operator 
must initiate remedial activities. Corrective action is completed when 
the owner or operator demonstrates compliance with the groundwater 
protection standards for three consecutive years.

L. Closure of Inactive Units.

    As discussed in Unit VI.A of this document, EPA proposed that 
inactive CCR surface impoundments that had not completed closure in 
accordance with specified standards by the effective date would be 
subject to all of the requirements applicable to existing CCR surface 
impoundments. EPA adopted this approach to create an incentive to 
expedite the closure of these units, with all of the significant risk 
mitigation that such a measure would entail. EPA is retaining this 
general approach in the final rule, but has revised the provision to 
grant inactive CCR surface impoundments more time to complete closure, 
consistent with the other closure provisions in the final rule. The

[[Page 21409]]

final rule extends the deadline to three years from publication of the 
rule in the Federal Register.
    The proposal was based on EPA's belief that the timeframes between 
publication of the final rule and the effective date would be 
sufficient for facilities to close inactive CCR surface impoundments. 
This was particularly true under the subtitle C option, where the 
timeframe between publication and the effective date could be as long 
as 18 months, due to the need for subsequent action by authorized 
states. Under the proposed rule, the maximum amount of time a facility 
would have to initiate and complete closure of a disposal unit was 
seven months. However, as discussed elsewhere in this preamble, EPA 
received numerous comments raising concern that these timeframes would 
essentially be ``impossible to meet'' for surface impoundments located 
in certain geographic and climatic conditions, as well as for all of 
the larger units. These comments convinced EPA that it had not 
adequately accounted for the complexities inherent in electric 
generating facility operations, and the different characteristics of 
CCR surface impoundments in designing the closure provisions in the 
proposal. EPA has revised the timeframes applicable to closures in the 
final rule accordingly in light of these issues. See Unit VI.M of this 
document. These same considerations apply with respect to this 
provision, and additional time is therefore necessary to make this 
option truly viable.
    EPA selected three years based primarily on two factors. EPA 
initially focused on the minimum amount of time necessary to close a 
CCR surface impoundment. As discussed in more detail in Unit VI.M of 
this document, there can be a substantial range in the amount of time 
needed to close a surface impoundment, depending on, for example, the 
size and location of the unit.
    However, a critical factor in EPA's decision is that under this 
approach these units will not be subject to the rule's groundwater 
monitoring or structural stability requirements (provided they complete 
closure within three years). Moreover, based on the information in the 
record, it appears highly unlikely that groundwater monitoring is 
currently being conducted at these units (as discussed in Unit IV.A of 
this document, the information on groundwater monitoring requirements 
applicable to existing units was extremely sparse, but many older units 
appear to lack effective groundwater monitoring systems). EPA 
considered that allowing these inactive units to remain in place 
without taking measures to address the continuing threat that these 
units present for a substantial amount of time could not be justified. 
EPA therefore focused on the amount of time authorized under the rule 
for implementation of the groundwater monitoring requirements (i.e., 2 
years from the effective date) and for key structural stability 
requirements (i.e., 18 months to complete key analyses).
    As discussed in more detail in the next section, the information in 
the record demonstrates that it is feasible to complete the closure of 
CCR surface impoundments within three years. EPA recognizes that larger 
CCR surface impoundments (i.e., above 40 acres) may not be able to 
close within this timeframe. However, to be able to support this 
provision, EPA must balance the risk mitigation achieved by closure of 
CCR surface impoundments against the risks inherent in allowing 
inactive CCR surface impoundments to remain in place for longer periods 
of time. The longer inactive CCR impoundments remain without all of the 
protections provided by the final rule, the greater the potential for 
significant health and environment impacts. Larger units are also the 
ones more likely to present the highest risks, and so warrant the 
greater oversight provided by application of all of the technical 
criteria to their operation (and closure). Consequently, EPA is unable 
to justify expanding this option to include the longer timeframes 
available under Sec. Sec.  257.102 or 257.103.
    The criteria for conducting the closure of inactive CCR surface 
impoundments are essentially the same as those applicable to active CCR 
units. Inactive units can either clean close units, or close with waste 
in place, subject to same performance standards in Sec.  257.102 for 
all other CCR units. If an inactive CCR surface impoundment is 
completely closed within the three year timeframe, no other 
requirements apply to that unit. This means that no groundwater 
monitoring or other post-closure care requirements would apply to these 
units. Once an inactive CCR surface impoundment has been breached and 
dewatered, the risks are essentially the same as the risks associated 
with an inactive CCR landfill, which are not subject to any 
requirements under the final rule.
    However, owners or operators of inactive CCR surface impoundments 
that have not completed closure within this timeframe must comply with 
all of the requirements applicable to existing CCR impoundments. If the 
facility intends to maintain the inactive unit indefinitely, whether to 
provide potential future capacity, or to continue to dredge the unit to 
provide material for beneficial use, or with the idea that it may be 
repurposed for other facility operations (e.g., to manage stormwater), 
there is no basis for distinguishing between these units and actively 
managed units on the basis of the potential risks. Thus, such units 
would need, for example, to meet all of the location and structural 
stability criteria (which could independently compel closure of the 
unit), install the groundwater monitoring system, and begin to monitor 
within the timeframes established in the final rule. This also means 
that any facility that initiates closure under this provision but fails 
to complete it within this timeframe, must comply with all groundwater 
monitoring requirements in Sec. Sec.  257.90-98 (e.g., install 
groundwater monitoring wells) as well as all of the post-closure care 
requirements.

M. Closure and Post-Closure Care

    Closure and post-closure care are an integral part of the design 
and operation of CCR landfills and CCR surface impoundments.\119\ EPA 
solicited public comment on closure and post-closure care requirements 
under a subtitle D approach in the proposed rule and sought additional 
comment on specific closure requirements in a subsequent notice of data 
availability.
---------------------------------------------------------------------------

    \119\ As discussed in the proposed rule, EPA's ``Guide for 
Industrial Waste Management'' documents the general consensus on the 
need for effective closure and post-closure care requirements 
(Chapter 11). This guide can be accessed at http://www.epa.gov/epawaste/nonhaz/industrial/guide/.
---------------------------------------------------------------------------

    For CCR landfills, the proposed closure and post-closure care 
requirements were modeled on current regulations that apply to 
municipal solid waste landfills, which are codified in part 258. In 
some cases, the proposed requirements were modified to reflect the lack 
of a mandatory permitting mechanism (see Unit V.A. of this preamble for 
additional information), in addition to other changes EPA believed were 
appropriate to ensure that there would be no reasonable probability of 
adverse effects from the wastes that remain after a CCR unit had 
closed. For CCR surface impoundments, the Agency modeled the proposed 
requirements on current regulations that apply to interim status 
hazardous waste surface impoundments, which are codified in part 265. 
Some additional proposed provisions were based on requirements 
currently applicable to water, sediment, or slurry impoundments and

[[Page 21410]]

impounding structures that are regulated by the MSHA. See 30 CFR part 
77, subpart C.
    The proposed rule included a number of closure and post-closure 
criteria, including: (1) Requirements to prepare closure and post-
closure plans; (2) requirements for conducting closure of a CCR unit 
when the CCR is removed and when the CCR is left in place, including 
design criteria for a final cover system; (3) timeframes to commence 
and complete closure activities; (4) closure and post-closure care 
certification requirements; and (5) requirements for conducting post-
closure care. The Agency received numerous comments on the proposed 
closure and post-closure criteria, with the majority of comments 
pertaining to the proposed timeframes for closure (i.e., timeframes for 
commencing and completing closure) of a CCR surface impoundment. As a 
result of these comments, EPA solicited additional comments on the 
timeframes for closure in a NODA published on August 2, 2013 (NODA 3). 
See 78 FR at 46944. The sections below explain the approach and 
rationale for the final rule closure and post-closure care criteria 
based on the comments received in response to the proposed rule and the 
NODA.
1. Closure Plan
    The Agency proposed to require that the owners or operators of CCR 
landfills and CCR surface impoundments prepare a written closure plan 
describing the closure of the unit and providing a schedule for 
implementation of the plan. 75 FR at 35207-08. The closure plan would 
describe the steps necessary to close the CCR unit at any point during 
the active life based on recognized and generally accepted good 
engineering practices. The proposal also identified the minimum 
information necessary to include in the closure plan. This information 
included: (1) An estimate of the largest area of the CCR unit that 
would ever require a final cover during the active life of the CCR 
unit; (2) an estimate of the maximum inventory of CCR that would ever 
be present on-site over the active life of the CCR unit; (3) a 
description of the final cover and the procedures to be used to install 
the final cover; (4) a description of how the facility will provide for 
major slope stability following closure; (5) a description of the 
measures the owner or operator will adopt to preclude the probability 
of future impoundment of water, sediment, or slurry; and (6) a schedule 
for the implementation of the closure plan. See proposed Sec.  
257.100(a) and (g). The proposed rule would also have required each 
owner or operator to develop the closure plan by the effective date of 
the final rule. Finally, EPA proposed to require the owner or operator 
to have the closure plan certified by an independent registered 
professional engineer, in addition to complying with all of the 
notification and posting requirements under the rule.
    EPA received few public comments on either the proposal to develop 
a closure plan or the individual elements of the closure plan. Some 
commenters generally supported the requirement for an owner or operator 
to develop a closure plan for the CCR unit, and no commenters opposed 
it. However, one commenter requested that EPA include more specific 
requirements for slope stability in the regulatory language beyond the 
general requirement to address major slope stability in the closure 
plan for units that close with waste in place.
    The Agency agrees that the proposed regulatory language should 
provide more specific criteria defining the expectations with regard to 
major slope stability. The proposed regulation merely required the 
owner or operator to ``provide for major slope stability'' in the 
closure plan, or in other words, to include measures to ensure that 
slope stability issues will be accounted for in designing the final 
cover. See 75 FR 35252.
    EPA explained that unit closure must provide for major slope 
stability to prevent the sloughing of the cover system over the wastes 
that will remain in the CCR unit over the long term. Sloughing of a 
land slope can occur when the earth material becomes saturated with 
water and incapable of maintaining the slope resulting in the movement 
or sliding of the earth material. 75 FR at 35209. Slope stability is a 
critical issue in the design of final cover systems for both surface 
impoundments and landfills because cover system slope instability has 
been attributed to a number of final cover system failures.\120\ More 
specifically, the primary causes of final cover system slope failure 
during construction have been identified as: (1) Placing soil over the 
sideslope geosynthetics from the top of the slope downward, rather than 
the toe of the slope upward; (2) using presumed values for critical 
interface shear strengths that were not conservative; and (3) using 
interface shear strength values from laboratory tests performed under 
conditions not representative of the actual field conditions. For final 
cover system slope failures after rainfall or thaw, the primary causes 
of failure have been identified as: (1) Not accounting for seepage 
forces; (2) clogging of the internal drainage layer, which leads to 
increased seepage forces; and (3) not accounting for moisture at the 
geomembrane and compacted clay liner interface (which weakened the 
interface) due to both rain falling on the compacted clay liner surface 
during construction and freeze-thaw effects.
---------------------------------------------------------------------------

    \120\ USEPA, ``Assessment and Recommendations for Improving the 
Performance of Waste Containment Systems,'' EPA/600/R-02/099, 
December 2002.
---------------------------------------------------------------------------

    Given that slope stability is a critical issue in the design and 
eventual performance of a final cover system, EPA has adopted a new 
criterion in the performance standard that all closures must meet: The 
owner or operator must ensure that the CCR unit is closed in a manner 
that will ``provide for major slope stability to prevent the sloughing 
or movement of the final cover system during closure and throughout the 
post-closure care period.'' See Sec.  257.102(d)(1)(iii). Or in other 
words, the owner or operator must design a final cover system with any 
measures necessary to ensure that the major slopes of the closed CCR 
unit remain stable. Consistent with the proposal, the closure plan must 
discuss how the final cover system will achieve the performance 
standards specified in the regulation, which will necessarily include 
how the measures taken to address major slope stability. As explained 
in the proposed rule, the original provision was based on existing MSHA 
standards, specifically the requirements under 30 CFR 77.216-5 which 
apply to abandoned water, sediment or slurry impoundments and 
impounding structures.\121\ 75 FR 35208-09. Under these requirements 
major slope stability includes long term stability considerations, such 
as ``erosion control, drainage, etc.'' These issues are equally 
relevant to the closure of CCR units, and EPA expects facilities to 
account for these factors in their final closure plans.
---------------------------------------------------------------------------

    \121\ The term ``abandoned'' is defined in the MSHA regulations 
under 30 CFR 77.217, and as applied to an impoundment or impounding 
structure such term means that work on the structure has been 
completed in accordance with a plan for abandonment approved by the 
District Manager.
---------------------------------------------------------------------------

    The remaining information elements of the closure plan have been 
adopted without revision (although EPA has reorganized the final 
regulatory text for greater clarity). These are briefly summarized 
below:
    a. An estimate of the largest area of the CCR unit ever requiring a 
final cover during the active life of the CCR unit. If

[[Page 21411]]

the owner or operator routinely closes portions of a CCR unit as the 
design capacity is reached, the closure plan should indicate the 
largest area of the CCR unit that will be open (and requiring a final 
cover) at one time.
    b. An estimate of the maximum inventory of CCR ever on-site over 
the active life of the CCR unit. If the owner or operator routinely 
closes portions of a CCR unit as the design capacity is reached, the 
closure plan should indicate the maximum inventory of CCR that will be 
open (and requiring a final cover) at one time.
    c. A description of the final cover and the procedures to be used 
to install the final cover. The closure plan should also discuss how 
the closure performance standard will be achieved.
    d. A description of the provisions to preclude the probability of 
future impoundment of water, sediment, or slurry. The final grades of 
the final cover system should promote surface water run-off and 
minimize erosion. The closure plan should also discuss the steepness of 
the slopes of the final cover system, in addition to the vertical 
spacing and width of benches.
    e. A schedule for the implementation of the closure plan.
    This rule also provides new procedures for amending an existing 
written closure plan. While the proposed rule did not specifically 
allow or require the owner or operator to revise an existing closure 
plan, EPA recognizes that available information and conditions known at 
the time the closure plan is prepared may very well change during the 
active life of the CCR unit, which could be decades in some cases. In 
order to eliminate any potential confusion over whether an owner or 
operator is allowed under this rule to revise the closure plan to 
reflect a change in conditions or circumstances, the final rule adopts 
new procedures for amending a written closure plan. These new 
procedures allow the owner or operator to revise the closure plan at 
any time provided the revised plan is placed in the facility's 
operating record, in addition to complying with all of the notification 
and posting requirements under the rule. Furthermore, the final rule 
requires the closure plan be amended any time there is a change in 
conditions that would substantially affect the written closure plan in 
effect.
    Finally, in a departure from the proposed rule, the final rule 
provides owners and operators one year from the rule's effective date 
to prepare the initial written closure plan, which is one year longer 
than proposed. EPA made this change as part of its effort to coordinate 
the compliance and implementation timeframes in the CCR rule with 
another Agency rulemaking--the Effluent Limitations Guidelines and 
Standards for the Steam Electric Power Generating Point Source Category 
(ELG) rulemaking--that may affect owners and operators of CCR units. 
See 78 FR 34442. As explained in that proposal, consistent with RCRA 
section 1006(b), EPA has sought to effectively coordinate any final 
RCRA requirements with the ELG requirements, to minimize the overall 
complexity of these two regulatory structures, and to facilitate the 
implementation of engineering, financial and permitting activities. 
EPA's goal is to ensure that the two rules work together to effectively 
address the discharge of pollutants from steam electric generating 
facilities and the human health and environmental risks associated with 
the disposal of CCRs, without creating avoidable or unnecessary 
burdens.
    EPA proposed to require facilities to complete a closure plan by 
the rule's effective date, or six months following the rule's 
publication. However, this would have required owners or operators to 
prepare closure plans approximately three months prior to publication 
of the ELG final rule. Given that an understanding of the ELG rule 
would likely affect the details and content of a closure plan, the 
Agency concluded that it would make no sense to require an owner or 
operator to prepare a closure plan within six months, only to have them 
update it months later, after the owner or operator understands the 
requirements of both the CCR and ELG final rules. No measureable 
environmental or health benefit would be gained by having a closure 
plan in place for those three months. Moreover, EPA wants to ensure 
that closure plans are well considered, and the knowledge that a plan 
may need to be substantially revised in the near future could create a 
contrary incentive.
    By extending the deadline for preparation of the closure plan by 
one year, owner or operators will have slightly more than six months 
after the ELG rule is published to complete a closure plan. This is 
consistent with the six month timeframe EPA originally proposed, which 
as noted, would have required completion of the closure plan within six 
months of publication of the final CCR rule.
2. Closure of a CCR Unit Through Removal and Decontamination
    The proposed rule would have allowed facilities to close a CCR unit 
either through CCR removal and decontamination of all areas affected by 
releases from the CCR unit (``clean closure'') or with CCR in place 
with a final cover system. The Agency proposed that if the owner or 
operator elects to clean close a CCR unit, CCR removal and 
decontamination are complete when constituent concentrations throughout 
the CCR unit and any areas affected by releases from the CCR unit do 
not exceed the numeric cleanup levels for those constituents found in 
CCR established by the state in which the CCR unit is located, to the 
extent that the state has established cleanup levels. 75 FR 35208. In 
the absence of state cleanup levels, the proposal stated that metals 
should be removed to either statistically equivalent background levels, 
or to maximum contaminant levels or health-based numbers. Once a 
facility had completed clean closure of a CCR unit, EPA proposed that 
post-closure care would not be required for that unit. EPA also noted 
that it was considering whether to adopt a further incentive for clean 
closure, under which the owner or operator could remove the deed 
notation required under the proposed rule, once all CCR has been 
removed from the facility and notification provided to the state.
    Several commenters urged EPA to not require clean closure as the 
only method of closing a CCR unit, arguing that clean closure is not 
feasible or not necessary. Others acknowledged that clean closure is 
not only a viable option for their CCR units, but in some cases it 
would be ``the only prudent closure option.'' A few commenters 
suggested criteria to determine the conditions under which clean 
closure would be appropriate. For example, one commenter agreed with 
EPA that the risk-based corrective action process (RBCA) would be 
useful in determining whether waste removal is appropriate at the site.
    EPA received relatively few comments on the specific standards for 
conducting clean closure. One commenter identified six criteria that 
should be included in any final regulation in order to allow a facility 
to have been deemed to have completed clean closure of a CCR surface 
impoundment and thereby avoid post-closure care. Some of the 
commenter's suggestions were comparable to requirements in the 
proposal. However the commenter also included requirements to ensure 
that adequate engineering controls were used to prevent contamination 
of soil and groundwater during excavation, and requirements for 
quarterly monitoring of shallow groundwater beneath the surface 
impoundment for a period of five years to demonstrate that no

[[Page 21412]]

residual CCR was left in place. Finally, a number of commenters 
supported a provision that would allow the owner or operator to remove 
the deed notation required provided all CCR is removed from the site.
    EPA did not propose to require clean closure nor to establish 
restrictions on the situations in which clean closure would be 
appropriate. As EPA acknowledged in the proposal, most facilities will 
likely not clean close their CCR units given the expense and difficulty 
of such an operation. Because clean closure is generally preferable 
from the standpoint of land re-use and redevelopment, EPA has 
explicitly identified this as an acceptable means of closing a CCR 
unit. However, both methods of closure (i.e., clean closure and closure 
with waste in place) can be equally protective, provided they are 
conducted properly. Thus, consistent with the proposal, the final rule 
allows the owner or operator to determine whether clean closure or 
closure with the waste in place is appropriate for their particular 
unit. EPA agrees that the RBCA process, using recognized and generally 
accepted good engineering practices such as the ASTM Eco-RBCA process, 
can be a useful tool to evaluate whether waste removal is appropriate 
at the site. It is, however, not a necessary prerequisite.
    EPA has adopted the provisions governing clean closure from the 
proposed rule with only one revision. The final provisions consist of 
two performance standards: First, the owner or operator must remove all 
CCR from the unit and decontaminate all areas affected by releases from 
the CCR landfill or surface impoundment. As part of meeting this 
performance standard, the final rule requires facility owners or 
operators to remove all wastes from the closing unit, and remove all 
liners contaminated with CCR waste and CCR waste leachate. The final 
rule also requires the owner or operator to remove and decontaminate 
all areas affected by releases from the CCR unit. This would require 
removal or decontamination of the underlying and surrounding soils and 
flushing, pumping, and/or treating the aquifer. The Agency interprets 
the term ``soil'' broadly to include both unsaturated soils and soils 
containing groundwater.
    Second, the final rule specifies that closure has been completed 
when all CCR in the unit and any areas affected by releases from the 
CCR unit have been removed and groundwater monitoring demonstrates that 
all concentrations of the assessment monitoring constituents listed in 
appendix IV to part 257 do not exceed either statistically equivalent 
background levels or MCLs. This standard encompasses both saturated and 
unsaturated soils, as well as the groundwater. As part of attaining 
this standard, facility owners and operators will need to document that 
any contaminants left in the subsoils (i.e., contaminated groundwater 
left in soils below the former landfill or impoundment) will not impact 
any environmental media including groundwater, surface water, or the 
atmosphere in excess of Agency-recommended limits or factors. 
Typically, any metals in these ``subsoils'' in excess of background 
levels are allowed to either naturally attenuate, or are removed by 
flushing. Once the facility has removed all of the assessment 
monitoring constituents listed in appendix IV down to background levels 
or MCLs the groundwater is considered to be ``clean'' and closure is 
complete.
    EPA disagrees that specific provisions requiring the use of 
adequate engineering controls to prevent contamination of soil and 
groundwater during excavation are necessary to ensure that closure will 
be protective. To the extent that any contamination of soil or 
groundwater has occurred during CCR removal, this would constitute a 
release (or an ``area affected by a release'') from the CCR unit, and 
the final performance standard requires the facility to ensure that 
this has been removed before closure is deemed to be complete.
    Contrary to the commenter's suggestion that quarterly monitoring 
for five years is necessary to demonstrate that no residual CCR was 
left in place, the rule requires a facility to document that all 
appendix IV concentrations are below MCL or background levels for two 
consecutive sampling events, using the statistical procedures in Sec.  
257.93(g). This is the same sampling required to demonstrate under the 
groundwater monitoring program that there is no longer a reason to 
suspect a source of contamination, and that consequently assessment 
monitoring can cease. EPA selected these provisions as the most 
factually analogous to the circumstances surrounding the clean closure 
of a CCR unit. Once a facility has removed the waste and any liner, the 
presumption is that the source of contamination has been removed as 
well. Although there may be site-specific factors that could support 
the need for a longer monitoring period, there is no factual basis to 
require a longer minimum period of sampling on a national basis.
    This represents a change from the proposal. EPA proposed a 
performance standard that required decontamination to either any state 
established numeric cleanup levels for CCR constituents, or in the 
absence of state cleanup levels, the removal of metals to either 
statistically equivalent background levels, or to MCLs, or health-based 
numbers. This was taken directly from the current part 258 standards 
for MSWLFs. EPA has deleted both of these standards as inappropriate 
for these units.
    The reference to state established clean up levels was 
inadvertently carried over from the existing part 258 regulations. As 
explained throughout this preamble, EPA is unable to rely on state 
programs to establish the specific standards under this rule; the 
record does not contain information on all state cleanup standards, and 
there is no mechanism for states to operate approved programs in lieu 
of federal programs.
    EPA determined that the requirement to clean all soils to 
background levels was equally inappropriate. In practice, EPA does not 
routinely require complete removal of all contamination (that is, 
cleanup to `background') from a closing unit even for hazardous waste 
units. Requiring CCR units to clean up soils to levels before the site 
was contaminated, would be more stringent than current hazardous waste 
policies. There is no basis in the current record to impose provisions 
for the remediation of CCR units that are more stringent than those 
imposed on hazardous wastes.
    Upon completion, the unit is exempt from the groundwater monitoring 
and any other post-closure care requirements. In addition, the final 
rule adopts the proposal to allow the owner or operator to remove the 
deed notation required under Sec.  257.102(i)(4), upon certification 
that clean closure has been completed. EPA proposed this option to 
create a further incentive for clean closure, and it is clear from the 
commenters, who uniformly supported this option, that it does so. Some 
commenters raised concern about the effect this option will have on 
state laws, which may not allow the deed notation to be removed. EPA 
notes that these criteria do not preempt state laws; to the extent 
state law requires the facility to retain a deed notation despite the 
completion of clean closure, those requirements will remain in place, 
notwithstanding this final rule.
3. Closure of a CCR Unit With CCR in Place
    The proposed rule would have also allowed facilities to close a CCR 
unit by leaving the CCR in place and installing a final cover system. 
The final cover

[[Page 21413]]

system would have been required to be designed and constructed to a 
have a permeability less than or equal to the permeability of any 
bottom liner system or the natural subsoils present, or a permeability 
no greater than 1 x 10-5 centimeters per second (cm/sec), 
whichever is less. The proposal would have also required an 
infiltration layer that contains a minimum of 18 inches of earthen 
material and an erosion layer containing a minimum of six inches of 
earthen material that is capable of sustaining native plant growth to 
help minimize erosion of the final cover. These proposed requirements 
were generally modeled after the performance standard and technical 
requirements contained in Sec.  258.60 for MSWLFs. 75 FR 35208. EPA 
also proposed that the final cover system would have to be designed to 
minimize the disruption of the final cover through a design that 
accommodates settling and subsidence and provides for major slope 
stability to prevent the sloughing of the closed CCR unit over the long 
term. These last two criteria are based on existing requirements for 
interim status units under RCRA part 265 and MSHA requirements under 30 
CFR part 77, subpart C, respectively.
    As proposed, CCR surface impoundments would have been subject to an 
additional set of performance standards. The owner or operator of a CCR 
surface impoundment would have been required to either drain the CCR 
unit or solidify the remaining wastes. In addition, the owner or 
operator would have been required to stabilize the wastes to a bearing 
capacity to support the final cover. The proposed criteria would also 
have required that the final cover for all CCR units be designed to 
minimize the migration of liquids through the closed CCR surface 
impoundment over the long term; promote drainage, and accommodate 
settling and subsidence so that the final cover's integrity is 
maintained. Finally, closure of the CCR unit would also have been 
subject to the general performance standard that the probability of 
future impoundment of water, sediment, or slurry be precluded.
    The Agency also proposed to allow owners or operators of CCR units 
to select an alternative final cover design. As proposed, the 
alternative final cover design would have required an infiltration 
layer that achieves an equivalent reduction in infiltration, and an 
erosion layer that would provide equivalent protection from wind and 
water erosion, as the infiltration and erosion layers specified for 
final covers described above. In addition, the proposed approach for 
alternative final cover designs would have also required certification 
by an independent registered engineer, notification being provided to 
the state that the alternative final cover design has been placed in 
the facility's operating record, and placement of the alternative final 
cover design on the owner or operator's publicly accessible Internet 
site.
a. Final Cover System Design
    EPA received comments supporting the proposed approach, while other 
commenters opposed the proposed final cover system design requirements. 
One state commenter generally supported using the part 258 final cover 
design requirements as a general model for CCR units. This commenter 
also requested that the Agency clarify whether new CCR units would be 
required to install a composite final cover system given that it was 
proposed that new CCR units would be required to designed and 
constructed with a composite bottom liner. Another state indicated that 
its state regulations allow final cover designs similar to that 
proposed by EPA, although the state requires a 24 inch infiltration 
layer and a 12 inch erosion layer. Another commenter referenced current 
research showing that soil-only covers may not be effective in 
minimizing infiltration over the long term under certain climates. This 
commenter recommended that a geomembrane should be made a standard 
component of the cover system. Other commenters stated that the final 
cover system should be a composite system consisting of a synthetic 
component and a low permeability clay component. A state commenter 
offered that post-closure maintenance of composite cap system 
incorporating a geomembrane has been challenging in that state. Another 
commenter stated that a compacted clay liner should not be used as a 
final cover for landfills due to the potential for settlement cracking, 
desiccation cracking, and root and animal penetration. Instead, it was 
suggested that if a single barrier system is used, then a benefit-cost 
analysis favors a geomembrane, and if a composite barrier is to be 
used, a benefit-cost analysis favors a composite system of a 
geomembrane and geosynthetic clay liner.
    The Agency also received many comments on the proposed approach to 
allow the use of alternative final cover systems. Most commenters 
supported allowing the use of alternative covers. One commenter stated 
that the use of geosynthetic clay liners in lieu of 18 inches of 
earthen material for the infiltration layer is a commonly accepted for 
cover systems for MSWLFs. This commenter also noted that that 
geosynthetic clay liners have documented permeability characteristics 
on the order of 1 x 10-9 cm/sec. Another commenter supported 
allowing the use of alternative cover systems because a one-size-fits-
all approach is not appropriate for final cover system designs. A state 
also offered that appropriately designed alternative final covers such 
as capillary barrier covers and evapotranspiration covers are being 
successfully used at facilities in the state.
    After considering comments received regarding final covers, the 
Agency is essentially finalizing the approach in the proposed rule with 
minor revisions. The final rule allows owners or operators to use a 
final cover system consisting of an infiltration layer and an erosion 
layer, provided the infiltration layer has a permeability less than or 
equal to the bottom liner or natural subsoils. However, regardless of 
the bottom liner or natural subsoils present, the final cover must have 
a permeability no greater than 1 x 10-5 cm/sec.
    To address the commenters' concerns that the final cover system may 
not function effectively as designed over the long term under certain 
circumstances, the rule also includes a performance standard that any 
final cover system must meet. This standard is modeled after the 
closure performance standard applicable to interim status hazardous 
waste units under Sec.  265.111. The final rule requires that any final 
cover system control, minimize or eliminate, to the maximum extent 
practicable, post-closure infiltration of liquids into the waste and 
releases of leachate (in addition to CCR or contaminated run-off) to 
the ground or surface waters. Thus, a facility must ensure that in 
designing a final cover for a CCR unit they account for any condition 
that may cause the final cover system not to perform as designed. This 
could include accounting for site conditions that may increase the 
likelihood that a cover would be susceptible to desiccation cracking or 
settlement cracking. Under this performance standard, if the cover 
system results in liquids infiltration or releases of leachate from the 
CCR unit, the final cover would not be an appropriate cover. The final 
rule requires the final cover system design to be certified by a 
qualified professional engineer that the design meets both the 
performance standard and cover system criteria.
    The final rule does not require the use of composite final covers, 
such as a geomembrane underlain by a compacted soil infiltration layer. 
This is also the

[[Page 21414]]

case in situations for a CCR unit that is designed with a composite 
bottom liner or if the permeability of the soil underlying the unit is 
comparable to the permeability of a geomembrane. As EPA has concluded 
for municipal solid waste landfills, in certain site-specific 
situations it may be possible to construct an infiltration layer that 
achieves an equivalent reduction in infiltration without matching the 
permeability in the bottom liner material. 62 FR 40710.
    Nonetheless, in certain locations, composite cover systems may be 
necessary to achieve the rule's performance standards. EPA acknowledges 
that under certain circumstances issues can arise with compacted clay 
barriers, particularly when used alone. These can include desiccation, 
freeze-thaw sensitivity, and distortion due to total and differential 
settlement of the underlying wastes. These issues can generally be 
addressed through proper maintenance of the cover system; and in fact 
the final rule requires as part of post-closure care that the owner or 
operator maintain the integrity and effectiveness of any final cover, 
including making repairs to the final cover to correct the effects of 
settlement, subsidence, erosion, or other events, and preventing run-on 
and run-off from eroding or otherwise damaging the final cover. 
Consequently, EPA is not mandating the installation of a composite 
liner system.
    However, fewer problems are typically seen with the use of 
composite cover systems. And while ongoing oversight and proper 
maintenance is necessary to ensure the efficacy of any cover system, 
less effort is generally involved to ensure the continued performance 
of a composite cover system. EPA therefore generally recommends that 
facilities install a composite cover system, rather than a compacted 
clay barrier, as the composite system has often proven to be more 
effective (and cost effective) over the long term. For these reasons, 
EPA also anticipates that composite cover systems will be recommended 
in many circumstances by qualified professional engineers.
    The final rule also allows the use of an alternative final cover. 
The rule requires that the alternative final cover must include 
infiltration and erosion layer that achieve equivalent performance as 
the minimum designs specified for final cover systems as discussed 
above. As discussed in the proposed rule, EPA included this provision 
to increase the flexibility for an owner or operator of a CCR unit to 
account for site-specific conditions. Moreover, these provisions will 
provide an opportunity to incorporate future technology improvements 
that would be missed if the rule required prescriptive design measures. 
In addition, these requirements would not supersede more stringent 
state requirements. Thus, if a state either has more prescriptive or 
more stringent standards in its state regulations applicable to CCR 
units, those state requirements would control any final cover system or 
alternative final cover system design.
    While the rule provides the owner or operator flexibility in 
selecting the final cover for the unit, EPA remains concerned about the 
lack of guaranteed state oversight on final cover selection. A final 
cover system that does not perform as designed may result in 
unacceptable infiltration of water into the closed CCR unit that may 
lead to leachate and releases from the unit. To address this concern, 
as well as the concerns raised by commenters regarding the long-term 
performance of certain cover systems by providing further assurance 
that the final cover system will perform over the long term, EPA has 
deleted the proposed provision that would have allowed owners or 
operators to shorten the length of the post-closure care period. As 
discussed in Unit M.9 below, the final rule requires facilities to 
conduct post-closure care for all CCR units for 30 years.
b. Performance Standards When Leaving CCR in Place
    EPA received no significant comments on the proposed performance 
standards. The Agency is therefore finalizing these requirements 
without revision from the proposal (although EPA has reorganized the 
final regulatory text for greater clarity). The performance standards 
are summarized below:
    i. As discussed in the previous section, the CCR unit must be 
closed in a manner that will control, minimize or eliminate, to the 
maximum extent practicable, post-closure infiltration of liquids into 
the waste and releases of CCR, leachate, or contaminated run-off to the 
ground or surface waters.
    ii. The CCR unit must be closed in a manner that will preclude the 
probability of future impoundment of water, sediment, or slurry.
    iii. The CCR unit must be closed in a manner that will provide for 
major slope stability, which is discussed is Unit M.1 of this document 
for closure plans above.
    iv. The CCR unit must be closed in a manner that will minimize the 
need for further maintenance of the unit.
    v. The CCR unit must be closed in the shortest amount of time 
consistent with recognized and generally accepted good engineering 
practices. The Agency added this performance standard to be consistent 
with the final provisions applicable for the timeframes for initiating 
and completing the closure of CCR units.
4. Timeframes for Closure
    The Agency proposed that closure of a CCR landfill or CCR surface 
impoundment must be initiated by the owner or operator no later than 30 
days following the known final receipt of CCR. To address concerns 
about ``inactive'' or abandoned units, the proposed rule also provided 
that a CCR unit must initiate closure no later than one year after the 
most recent receipt of CCR if the CCR unit had remaining capacity and 
there was a reasonable likelihood that the CCR unit would receive 
additional CCR (i.e., the rule would have forced the facility to close 
the CCR unit). See 77 FR at 35209 and proposed Sec.  257.100(j). In 
addition, the proposed rule would have required an owner or operator to 
complete closure activities within 180 days of initiating closure. See 
proposed Sec.  257.100(k). Thus, the maximum amount of time a facility 
would have had to initiate and complete closure of a CCR unit was seven 
months.
    While the existing closure criteria for MSWLFs allow the Director 
of an approved State to grant time extensions for closure (both to 
initiate and to complete closure) if steps are taken to prevent threats 
to human health and the environment from the unclosed unit, EPA 
proposed not to include similar provisions for owners or operators of 
CCR units. At proposal, the Agency believed that extending the closure 
deadlines was inappropriate because, in the absence of an approved 
state program, the owner or operator could unilaterally decide to 
extend the time for closure of a CCR unit, without any basis, or 
oversight by a regulatory authority. 75 FR 35209.
    EPA received numerous comments in response to the proposed 
deadlines under the subtitle D proposed approach. Industry and state 
commenters stated that the proposed deadlines to begin and complete 
closure activities (30 and 180 days, respectively) are technically 
impracticable and simply too short for the vast majority of CCR units, 
especially for CCR surface impoundments to complete closure. Commenters 
stated that a 30-day deadline to initiate closure activities may not be 
workable in situations such as when there are construction

[[Page 21415]]

limitations due to seasonal or climatic conditions, and should not be 
required in circumstances when a coal-fired generating unit is 
temporarily idled (e.g., maintenance related outages or an outage 
corresponding with a CCR handling system conversion). Regarding the 
amount of time needed to close a unit, numerous commenters noted that 
it would be impossible to properly complete closure activities within 
the proposed 180 days at most CCR surface impoundments due to the 
length of time needed to dewater an impoundment and stabilize the 
wastes prior to constructing the final cover system. For example, 
commenters pointed out that dewatering of a surface impoundment alone 
can take several years to complete because impoundments can be hundreds 
of acres in size. One commenter provided information related to an 
ongoing CCR surface impoundment closure where the dewatering and ash 
stabilizing phases of closure took two years to complete. Commenters 
also stated that because a large number of CCR units will have to be 
closed during roughly the same timeframe, facilities may not be able to 
obtain the necessary specialized personnel, equipment, and materials 
(e.g., clay or fill material, liner materials) to close multiple units 
simultaneously. This issue may be further complicated in locations 
where multiple facilities are competing for the same limited resources. 
Commenters further argued that adopting the same closure deadlines 
applicable to MSWLFs is not appropriate given differences in size, 
design, and operation (e.g., CCR surface impoundments contain large 
volumes of water, MSWLFs typically close each component cell when it 
reaches its disposal capacity). As a result of these concerns, 
commenters recommended that EPA extend the deadlines both to commence 
and complete closure activities. The majority of the these commenters, 
however, urged EPA not to establish specific deadlines for closure and 
instead require facilities to close a CCR unit consistent with a 
closure plan approved by a state, or developed and certified by a 
qualified professional, such as a professional engineer.
    In a subsequent NODA, the Agency solicited additional public 
comment on several different options to address these concerns. 78 FR 
at 46944-46. With respect to the deadline to initiate closure, EPA 
presented several examples of routine and legitimate circumstances in 
which CCR units would not receive CCR for periods longer than one year, 
even though the facility intended to continue to use the unit. For 
example, EPA discussed circumstances in which the facility alternates 
between two surface impoundments, only one of which is operational at a 
time. Once the impoundment has reached capacity, the facility dewaters 
the unit, and begins to send CCR to the second impoundment. Once the 
unit is dewatered, the CCR is excavated and disposed in an adjacent 
landfill. The time to fill these units has varied over the years as 
demand has fluctuated, but a typical time to fill a unit with CCR is 
two years, perhaps longer, during which the other unit is ``idle,'' in 
that it does not ``receive CCR,'' but it remains operational.
    The Agency also solicited comment on a revised approach to the 
deadline to initiate closure. The approach entailed establishing a 
rebuttable presumption that if the CCR unit has not received waste 
within a particular period of time (e.g., 18-24 months), the CCR unit 
would be considered inactive and unit closure would be required to 
begin within a specified time. However, if the facility could 
substantiate that there was a reasonable likelihood that the CCR unit 
would again receive CCR in the future and also was able to document 
certain findings, the owner or operator would not need to immediately 
commence closure of the CCR unit. In the NODA, EPA discussed several 
examples of situations that could support a demonstration that 
immediate closure of the CCR unit was not necessary. One example was if 
an owner or operator could document that a CCR unit had been dedicated 
to a temporarily idled coal-fired generating unit and there was a 
reasonable likelihood that CCRs would be disposed in the CCR unit once 
the coal-fired generating unit resumed operation. Another situation 
presented was a CCR unit dedicated to a coal-fired generating unit that 
was not burning coal at the time (e.g., electricity was being generated 
with other fuels such as natural gas), but the facility needed the CCR 
unit following resumption of coal burning. A final example involved 
normal facility operations that include periods during which the CCR 
unit does not receive CCR for extended periods (e.g., the alternating 
use of two CCR surface impoundments discussed above). As part of this 
approach, the Agency solicited comment on whether to limit the length 
of time an owner or operator can maintain an idle CCR unit.
    With respect to the deadline for completing closure, EPA 
acknowledged in the NODA that different deadlines, at least for the 
larger CCR units, were warranted. Information that the Agency has 
obtained throughout the rulemaking confirmed commenters' claims that 
the timeframes originally proposed to complete closure of CCR surface 
impoundments will be practicably infeasible for the larger 
impoundments. However, the Agency cautioned that any ultimate timeframe 
provided in the rule that would be practicable for the largest CCR 
units would be far too long to justify as timeframes for closure of the 
smaller impoundments. EPA explained that it intended to examine 
available closure plans for CCR surface impoundments to determine 
whether there are consistent timeframes or other factors that EPA could 
adopt as part of the regulations. EPA specifically identified two 
closure plans of CCR units that were scheduled to close as a possible 
source of useful information. These plans projected that closure would 
take multiple years to complete for modestly-sized CCR surface 
impoundments (i.e., less than 50 acres).
a. Deadlines To Initiate Closure
    In response to the NODA, most utility commenters stated that the 
time to initiate closure should be tied to reasonable triggers that 
account for the diverse uses of CCR surface impoundments and CCR 
landfills. In particular, these commenters recommended that closure not 
be initiated for an idled CCR unit if the CCR unit was expected to 
receive additional waste in the future, whether CCR or any other waste 
the unit may be authorized to manage. These commenters also supported 
the scenarios EPA described in the NODA as examples of legitimate 
situations that could warrant delaying the immediate closure of a CCR 
unit. Many of these commenters generally agreed that the rebuttable 
presumption alternative discussed in the NODA could be an appropriate 
approach for closure, in particular for CCR units not covered by a 
state-approved operating plan, provided the regulatory approach would 
be implemented in a manner that did not restrict other legitimate uses 
of the CCR unit. Many of these commenters also asserted that a limit on 
the length of time a CCR unit can remain idle is not practical because 
the owner or operator will not be able to predict with any degree of 
certainty how long a CCR unit will be idled. Several of these 
commenters also urged EPA to specify in the final rule what EPA 
intended by the phrase ``initiation of closure;'' that is, that EPA 
define the activities or actions the owner or operator must take by the 
deadlines specified in the rule.
    A trade organization and other commenters warned that strict 
restraints on the initiation (and completion) of

[[Page 21416]]

closure of CCR units would pre-empt opportunities for reclaiming CCR 
from these CCR units for beneficial use of CCR. These commenters 
recommended that the final rule create meaningful incentives for the 
beneficial use of CCR already in CCR units which will become 
unavailable to reclamation once a final cover system is put in place. 
For example, one commenter suggested that an incentive could be 
deferring deadlines for closure of a CCR unit if an owner or operator 
reduces its net tonnage by a set amount, such as 10,000 tons per year, 
if the CCR is beneficially used. EPA also received comments from 
several states that generally supported the rebuttable presumption 
concept. One state supported a longer rebuttable presumption time 
period of three years that could be extended if approved by the state 
on a case-by-case basis.
    After consideration of all of the public comments, the Agency is 
adopting an approach that largely mirrors the approach outlined in the 
NODA. Closure of a CCR unit is triggered in one of three ways. The 
first is upon the known final receipt of waste (CCR or otherwise), or 
when an owner or operator removes the known final volume of CCR from 
the CCR unit for the purpose of beneficial use of CCR. Under these 
scenarios, the final rule requires an owner or operator to commence 
closure of the CCR unit within 30 days of such known final receipt or 
known final volume removal, whichever date is later.
    The second way closure can be triggered relates to ``idled'' CCR 
units. This applies to situations in which the CCR unit has remaining 
disposal, treatment, or storage capacity, or there has been a temporary 
pause in the removal activities of CCR from the CCR unit. In these 
situations, the rule establishes a presumption that the owner or 
operator must initiate closure of the CCR unit no later than two years 
after the most recent receipt of CCR or any non-CCR waste stream, or no 
later than two years after the most recent date that CCR was removed 
from the CCR unit for the purpose of beneficial use, whichever date is 
later. The rule, however, provides procedures for an owner or operator 
of the CCR unit to rebut this presumption and obtain additional time, 
provided the owner or operator can make the prescribed demonstrations.
    The final way closure is triggered is when a CCR unit fails to meet 
certain of the technical criteria. Specifically, an owner or operator 
may be compelled to close a CCR unit in the following circumstances: 
(1) If the CCR unit has been sited inappropriately; i.e., cannot meet 
the applicable location criteria; (2) if an unlined CCR surface 
impoundment is found to contaminate groundwater in excess of a 
groundwater protection standard; or (3) if a CCR surface impoundment 
cannot demonstrate the minimum factors of safety regarding structural 
integrity of the CCR unit. When closure is triggered under these 
circumstances, the owner or operator must initiate closure of the CCR 
unit within six months. Each of these is discussed in more detail 
below.
i. ``Known Final Receipt'' of CCR
    Several commenters suggested that the rule not link the deadlines 
to initiate closure solely to when a CCR unit ceases to receive CCR. 
Many of these commenters provided information that CCR units also serve 
functions other than managing CCR, including the management of other 
wastes or water treatment. Thus, while there are periods of time that 
certain CCR units will receive both CCR and non-CCR wastes, there are 
also other times when the same CCR unit will only receive non-CCR 
wastes or perform other forms of active waste management in the unit, 
e.g., specific water treatment functions. EPA agrees that these are 
legitimate waste management activities, and EPA is aware of no risks 
that would warrant cessation of such activities simply because the unit 
is no longer receiving CCR. Therefore, in response to these comments, 
the final rule no longer requires closure based solely upon the receipt 
of CCR. Instead, the final rule requires closure to be initiated after 
the CCR unit ceases to receive any waste or waste stream into the CCR 
unit. See Sec.  257.102(e)(1) and (e)(2) in the rule.
    The Agency also agrees with those commenters that supported 
delaying the commencement of closure of a CCR unit if substantial 
quantities of CCR are removed from the CCR unit for the beneficial use 
of the waste. This could include, for example, removal of CCR from a 
CCR unit followed by its use as a partial replacement for Portland 
cement. As discussed in Unit IV.B of this preamble, EPA has identified 
significant benefits from reducing the disposal volumes of CCR in CCR 
landfills and CCR surface impoundments, including reduced risks 
associated with the practice of CCR disposal, benefits from reducing 
the need to mine and process virgin materials, and energy and 
greenhouse gas benefits. EPA finds these potential benefits compelling 
and is therefore revising the closure requirements in the rule to 
accommodate the removal and beneficial use of CCR. EPA has therefore 
revised the rule to provide that closure of an otherwise idled CCR unit 
is not immediately triggered, as long as the owner or operator is 
removing substantial quantities of CCR from the unit. However, once 
removal of CCR for beneficial use is no longer taking place, the rule 
would require the owner or operator to initiate closure of the CCR 
unit. See Sec.  257.102(e)(1) and (e)(2) in the rule.
    After considering comments received regarding the specific 
timeframe by which closure must be initiated following known final 
receipt of wastes, the Agency is finalizing the 30 day timeframe from 
the proposed rule. Several commenters expressed concern that 30 days is 
too short because it does not account for the potential that weather or 
seasonal concerns may interfere or cause substantial delay. The Agency 
acknowledges that weather or seasonal effects can delay certain 
activities, but disagrees that the rule provision needs to be revised 
to account for those. This provision does not require that specific 
actions or activities must be initiated during this 30-day period. For 
example, the rule does not require the installation of the final cover 
system (or the commencement of removal of CCR from the CCR unit) 
necessarily begin within this 30-day period. Instead, the provision is 
more flexible; the owner or operator can initiate closure by taking 
other actions necessary to implement the closure plan that are not 
weather or seasonal dependent, such as turning off pumps supporting 
sluice lines or taking any steps necessary to comply with any state or 
other agency standards that are a prerequisite to initiating closure. 
Provided the owner or operator has started to take the measures to 
implement the closure plan that can be feasibly undertaken, the 
facility will have complied with this requirement.
    The 30-day period remains equally appropriate under the wider 
provision that allows closure to be triggered either by the known final 
receipt of all wastes in the unit, or upon the known final volume 
removal of CCR for beneficial use of CCR. There are no facts unique to 
these circumstances that would necessitate an extension beyond the 30 
day timeframe. Furthermore, as the terms ``known final receipt'' and 
``known final volume removal'' suggest, the owner or operator has made 
the determination to cease managing waste in the CCR unit, or to cease 
removing CCR from the CCR unit for beneficial use purposes. This will 
likely occur in situations where the CCR unit is reaching its disposal 
capacity (or treatment capacity when the CCR unit is receiving non-CCR 
waste streams) or the

[[Page 21417]]

owner or operator intends to close the CCR unit for other purposes 
(e.g., the closing of a CCR surface impoundment following conversion to 
dry handling of CCR). Given that these situations can generally be 
anticipated and planned for in advance, EPA is not aware of 
circumstances that would prevent owners or operators from at least 
commencing closure within this 30-day period. In summary, the owner or 
operator must commence closure of the CCR unit with 30 days of known 
final receipt of CCR or any non-CCR waste stream, or within 30 days of 
known final removal of CCR for beneficial use, whichever date is later.
ii. Temporarily Idled Units
    This situation involves CCR units with remaining CCR disposal or 
storage capacity (or treatment capacity for non-CCR waste streams) that 
may sit idle for extended periods of time (e.g., potentially years at a 
time); however, the owner or operator intends to continue to maintain 
the idled unit to receive CCR or non-CCR waste streams in the future. 
EPA proposed that these CCR units could remain idle for up to one year, 
but that closure of the CCR unit would have to be initiated no later 
than one year after the most recent receipt of CCRs. See 75 FR 35252 
(proposed Sec.  257.100(j)). The majority of commenters claimed that 
one year was too short and would require the premature closure of CCR 
units that would be needed in the future. In response to these comments 
and new information documenting examples of legitimate circumstances in 
which CCR units were idled for more than one year, EPA solicited 
comment on a revised approach to establish longer timeframes to 
initiate closure for temporarily idled CCR units. As discussed 
previously, this approach entailed establishing a rebuttable 
presumption that if the CCR unit has not received waste within a 
specified period of time (i.e., 18 months to two years), the CCR unit 
would be considered inactive and closure of the CCR unit would be 
required. However, this time could be extended beyond the 18 months or 
two years if the facility could substantiate certain findings. See 78 
FR at 46945.
    After considering comments received, the Agency is essentially 
finalizing the approach presented in the 2013 NODA. Specifically, in 
situations where the CCR unit has remaining disposal or storage 
capacity (or treatment capacity for non-CCR wastestreams) and there is 
a reasonable likelihood that the CCR unit will receive additional CCR 
or non-CCR waste in the future, the final rule allows the owner or 
operator to keep the CCR unit available for use for up to two years. 
However, if the CCR unit has not received CCR or any non-CCR waste 
within two years of the last receipt of CCR or any non-CCR waste, 
whichever date is later, the rule requires closure of the CCR unit 
unless the owner or operator can document that additional time is 
necessary to accommodate routine operations and legitimate waste 
management activities.
    The Agency agrees that it is not necessary to require closure of 
temporarily idled CCR units after one year. Information in the record 
documents numerous examples of legitimate circumstances in which CCR 
units were idled for more than one year. In most of the examples 
provided CCR units are temporarily idled for periods that can last more 
than one year, but typically use of the CCR units resumes within 
approximately two years. Based on this information EPA has concluded 
that a two year timeframe before presumptively requiring closure of a 
CCR unit would be more consistent with current practice, and is better 
supported by the available information.
    This same information documented that there can be situations in 
which a CCR unit is idled for longer periods of time (e.g., a coal-
fired boiler may be idled for years during which another fossil fuel is 
burned (e.g., natural gas), and the CCR unit will be needed when the 
utility returns to coal burning. In order to obtain additional time 
beyond two years, the owner or operator must document in writing both 
that the CCR unit has remaining disposal or storage capacity and the 
facts that support a conclusion that there is a reasonable likelihood 
that the CCR unit will accept CCR or non-CCR waste in the foreseeable 
future. The facility would need to substantiate those findings, 
including the specific reasons the owner or operator believes ``that 
there is a reasonable likelihood that CCR will be disposed in the waste 
disposal unit.'' These findings would need to be certified by the owner 
or operator of the CCR unit.
    The rule identifies examples of specific scenarios that would 
support a determination that there is a continuing need for the unit to 
support future waste management activities (e.g., that the CCR will 
resume receiving CCR or non-CCR waste in the future). These are 
intended to be illustrative rather than an exclusive list; there may 
well be additional circumstances in which routine operations or 
legitimate waste management practices would support the necessary 
determination. The particular situations identified in the rule 
generally match those discussed in the NODA or reflect situations 
identified in public comments. Specifically, the rule identifies four 
particular circumstances: (1) Normal plant operations include periods 
during which the CCR unit does not receive wastes (CCR or non-CCR waste 
streams). This may include the alternating use between one CCR unit 
that receives CCR while dewatering or removing CCR from a second unit. 
(2) The CCR unit is dedicated to a coal-fired boiler unit that is 
temporarily idled (i.e., CCR is not being generated) and there is a 
reasonable likelihood that the coal-fired boiler will resume operations 
in the future. (3) The CCR unit is dedicated to an operating coal-fired 
boiler (i.e., CCR is being generated); however, no CCR is being placed 
in the CCR unit because the CCR is being entirely diverted to 
beneficial uses, but there is a reasonable likelihood that the CCR unit 
will again be used in the foreseeable future. (4) The CCR unit 
currently receives only non-CCR waste streams and those non-CCR waste 
streams are not generated for an extended period of time, but there is 
a reasonable likelihood that the CCR unit will again receive non-CCR 
waste streams in the future. As noted, a facility must substantiate 
these findings; it is not sufficient to merely repeat the words of the 
regulation and conclude that additional time is warranted.
    The final rule allows an owner or operator to obtain additional 
two-year time extensions for as long as the owner or operator continues 
to be able to provide a factual basis to justify the need for 
additional time via a written demonstration. Because these idled units 
must continue to comply with all applicable technical requirements, 
including those for groundwater monitoring, corrective action, and 
structural stability, a fixed or definitive limit on the amount of time 
that a CCR unit can sit idle is not necessary.
    In addition, the Agency agrees that the final rule should better 
define the actions or activities that constitute ``initiation of 
closure'' of a CCR unit. A clear definition will assist in the 
implementation and understanding of the rule. Commenters suggested a 
number of actions or activities, any one of which would be sufficient 
to show that closure of the CCR unit has been initiated. Examples 
provided by the commenters included the removal of CCR sluice lines; 
beginning the necessary permitting processes (i.e., submitting a 
completed permit application); turning off pumps supporting the sluice 
lines; preparing a bid for contractors; or procuring capping materials 
such as clay or top soil.

[[Page 21418]]

    The final rule specifies that closure has been initiated when the 
owner or operator takes two actions. The first action is that the owner 
or operator must have permanently ceased placing CCR and non-CCR waste 
streams in the CCR unit. As suggested by commenters, permanent removal 
of CCR sluice lines or inactivation of the pumping system supporting 
the sluicing operation would be evidence that placement of CCR and non-
CCR waste streams has ceased. The second action is that the owner or 
operator must have taken steps to implement the written closure plan 
required by the rule. This second action would include submitting a 
completed application for any required state or agency permit or permit 
modification in order to implement closure of the CCR unit, or taking 
any steps necessary to comply with any state or other agency standards 
or regulations that are a prerequisite to initiating or completing the 
closure of the CCR unit. Once the owner or operator has completed both 
of these actions, closure of the CCR unit has been initiated for 
purposes of this rule. See Sec.  257.102(e)(3) in this rule.
iii. Closure for Cause
    Finally, the Agency is clarifying that the closure initiation 
timeframes specified above--the 30 day period for known final receipt 
or known final volume removal and the 2 year period for temporarily 
idled CCR units--do not apply to closures initiated for cause. As 
discussed elsewhere in the preamble, the final rule requires certain 
CCR surface impoundments and CCR landfills to close. The situations 
include: Unlined CCR surface impoundments whose groundwater monitoring 
shows an exceedance of a groundwater protection standard; existing CCR 
surface impoundments that do not comply with the location criteria; CCR 
surface impoundments that are not designed and operated to achieve 
minimum safety factors; and existing CCR landfills that do not comply 
with the location criteria for unstable areas. In these situations, the 
final rule specifies that the owner or operator must initiate closure 
activities within six months of making the relevant determination that 
the CCR unit must close.
b. Deadlines To Complete Closure
    In response to the August 2013 NODA, many utility commenters stated 
that the time period to complete closure must be sufficiently flexible 
to account for the inherent uncertainties in predicting a closure 
schedule. These commenters pointed to potentially innumerable 
complications and circumstances beyond the control of the owner or 
operator that render it nearly impossible to predict with precision 
when the closure of a CCR unit will be completed. These commenters also 
believe it is impractical and unrealistic for the rule to subject the 
closure of CCR units to any type of fixed regulatory structure. They 
maintained their position from the proposed rule that it would be 
impossible to properly complete closure of most CCR surface 
impoundments within 180 days. Their recommendation is to allow closure 
timeframes to be governed by the a state-approved closure process, 
which would include the owner or operator developing and submitting a 
closure plan to the state and mechanisms for the state to verify and 
enforce compliance with all closure requirements, including the closure 
plan. Under this approach, the owner or operator's compliance with the 
requirements of the state-approved closure process (including following 
the closure plan, completing mitigation, etc.) would represent 
compliance with this rule's closure requirements. For CCR units not 
subject to a state-approved closure process, these commenters 
recommended that the owner or operator should demonstrate compliance 
with the CCR closure requirements by submitting a closure plan to the 
state that is certified by an independent professional engineer. In 
this case, because there is not direct state oversight and 
administration of the closure process, the timelines in the closure 
plan could be subject to a modified set of tiered timeframes for 
completing closure, provided owners or operators could demonstrate that 
more time is needed to close the unit on a case-by-case basis.\122\ 
These commenters also opposed any closure approach with firm and 
inflexible timeframes because no single factor (e.g., the acreage of 
the CCR unit or the volume of CCR in the unit) is determinative in all 
instances of how long it will take to complete closure of the CCR unit. 
Commenters also cautioned that pre-closure closure plans (and the 
closure schedules contained therein) may not be an actual reflection of 
the time it will take to close the unit due to unforeseen or variable 
conditions. Finally, these commenters also generally opposed the idea 
discussed in the NODA of petitioning the Agency for a site-specific 
rule to vary from a generally applicable deadline.
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    \122\ The tiered timeframes for completing closure could be 
based on the size of the CCR unit (after obtaining necessary state 
and local approvals): (1) Within 3 years for an impoundment with an 
area less than 20 acres; (2) Within five years for an impoundment 
between 20 and 50 acres; (3) Within 8 years for an impoundment 
between 50 and 75 acres; (4) Within 10 years for an impoundment with 
an area of 75 acres or more; and (5) Within 180 days for a landfill. 
Under this approach, the owner or operator could demonstrate the 
need for additional time to close the CCR unit.
---------------------------------------------------------------------------

    Many commenters described the numerous factors that could affect 
timeframes for closure of a CCR unit. Most comments were specific to 
CCR surface impoundments where closures are typically more complex as 
compared to CCR landfills due to the presence of water in impoundments. 
Factors most often cited by the commenters that may affect the time 
required to close a CCR unit included: (1) The size and volume of CCR 
in the unit; (2) the geotechnical characteristics of the CCR; (3) the 
type or design of the surface impoundment (i.e., diked, incised, valley 
fill, and side hill); (4) the need to coordinate or obtain approvals 
from state permitting officials; (5) the availability of qualified 
engineers, contractors, and materials since closing a CCR unit is a 
specialized activity, especially given that many units may be required 
to close simultaneously; (6) climate and weather that can affect 
dewatering operations and the length of a construction season; (7) the 
time needed to obtain replacement disposal capacity for a closing unit 
that would ensure ongoing facility operations; and (8) dam safety 
considerations during closure. Many of commenters identified that the 
dewatering process (an early necessary step in the closure process) as 
being a site-specific issue, as the time that will be needed to dewater 
an impoundment can vary considerably depending on the type of CCR unit, 
the volume of CCR in unit, and the geotechnical properties of the CCR. 
Several commenters also cited that closure times for some CCR units 
will require substantial volumes of fill material to properly grade a 
closing surface impoundment to facilitate positive drainage from the 
closed unit. These commenters provided estimates on the volumes of fill 
material needed and showed that the earthmoving aspect of this step 
alone can take many years to complete in some cases.
    Several state commenters generally supported the tiered closure 
alternative discussed in the NODA. However, these commenters urged EPA 
to include provisions in the rule to provide flexibility for closing 
units to demonstrate the need for additional time on a case-by-case 
basis.
i. Timeframes for Completing Closure
    In the August 2013 NODA the Agency solicited comment on ways to 
establish categories of timeframes that would adequately account for 
the various factors that can affect the amount of

[[Page 21419]]

time needed to properly close a CCR surface impoundment. One approach 
discussed in the NODA was called the ``tiered approach'' that was based 
on comments received in response to the proposed rule. Under that 
approach, the final rule would establish fixed timeframes to complete 
closure that varied depending on the size of the impoundment (i.e., 
surface area acreage). The Agency stated in the NODA that the concept 
of a tiered approach was appealing; however, the precise basis for the 
distinctions (i.e., unit size cutoffs) and timeframes were not clear. 
EPA further explained its concern that factors other than size (e.g., 
climate, geography, unit configuration) would also appear to be 
relevant, and that any timeframes should account for those other 
factors. EPA encouraged commenters interested in supporting a tiered 
approach to provide the rationale and data to support any suggested 
categories of timeframes. 78 FR 46946. Most commenters opposed the 
tiered approach by itself (i.e., an approach without an accompanying 
process by which an owner or operator could obtain additional time due 
to site-specific circumstances) because they felt there simply are too 
many factors that can affect closure timeframes. These commenters 
concluded that basing closure timeframes on a subset of factors would 
not be appropriate. As one commenter noted, a 20 acre impoundment 10 
feet deep can likely be dewatered and closed more quickly than a 20 
acre impoundment 30 feet deep.
    After considering comments and information available on closure 
timeframes, EPA has concluded that there are insufficient data and 
information to adopt the kind of tiered approach discussed in the NODA. 
EPA is convinced that the available information does not support an 
approach that would establish fixed and definitive timeframes for 
closure, based on a select subset of factors that distinguish between 
surface impoundments (e.g., a 50 acre diked impoundment holding 500 
acre-feet of CCR with a hydraulic conductivity of 1 x 10-5 
centimeters per second located in a state in the southwest with a 
permitting program would be required to close in four and one-half 
years, while a 50 acre cross valley impoundment holding 1,500 acre-feet 
of CCR with a hydraulic conductivity of 1 x 10-6 centimeters 
per second located in a state in the upper midwest with a permitting 
program would be required to close in seven years, etc.). While 
information is available for surface impoundments on certain factors, 
such as the size and type of the unit and geographic information, the 
Agency has little to no data for a number of other key factors. For 
example, EPA has no information on the geotechnical properties of the 
CCR that can affect the time needed to dewater a unit, the volumes of 
clays, soils, and other materials that will be needed for closure, and 
information on the time needed to obtain state approvals (in accordance 
with state CCR programs) related to closure of a unit.
    In discussing the tiered approach EPA noted that commenters had 
suggested that the largest CCR surface impoundments (i.e., those having 
a surface area greater than 75 acres) should be subject to a site-
specific deadline to complete closure. In the NODA, the Agency 
explained that a site-specific deadline may not be practicable unless 
the rule were to establish a ``variance'' process as part of the rule. 
78 FR 46946. Under a variance approach, EPA would establish a specific 
deadline (e.g., closure must be completed no later than five years from 
the date closure activities are initiated), but would allow facilities 
to petition EPA for a site-specific rule to establish an alternate 
deadline. In response to the NODA, some commenters expressed interest 
in such an approach, but other commenters found the approach not 
practicable since each owner or operator would need to petition the 
Agency for a site-specific rule. Some commenters believed that a site-
specific rule process, which would necessarily involve a notice and 
comment process, would be an unwieldy process leading to unnecessary 
delays. The Agency agrees that this is also not a practical alternative 
to establish timeframes to complete closure.
    Recognizing the numerous factors that can affect the amount of time 
needed to close an impoundment, many commenters suggested EPA not 
establish any type of fixed regulatory deadline for closure. Instead, 
these commenters recommended that the rule allow closure timeframes to 
be governed by a state-approved closure process. Under this process 
suggested by commenters, an adequate state-approved closure process 
would include one where the owner or operator developing and submitting 
a closure plan to the state and mechanisms for the state to verify and 
enforce compliance with all closure requirements, including the closure 
plan. Under the commenter's recommendation, compliance with the 
requirements of the state-approved closure process would not be 
compliance with the closure requirements of this rule. As discussed 
elsewhere in this preamble, under subtitle D of RCRA, the Agency cannot 
rely on the existence of a state permitting authority to implement the 
subtitle D requirements.
    Some other commenters suggested EPA not establish any type of fixed 
regulatory deadline for closure in the rule, and instead rely on the 
closure plan developed and certified by a professional engineer. The 
Agency disagrees that this approach would meet the protectiveness 
standard of RCRA section 4004(a). CCR units present significant risks, 
and it is critical that facilities complete closure expeditiously--
particularly those that are closing because they are structurally 
unsound or are contaminating groundwater. To be able to determine that 
the rule will be protective, the final rule must limit the discretion 
of individual facilities, many of whom may have significant incentives 
for delay, and avoid the potential for abuse. Moreover, in contrast to 
corrective action, where EPA was truly unable to establish an outer 
limit on the necessary timeframes--including even a presumptive outer 
bound--closures, while complex, do not vary to the same degree as site 
remediation actions. Consequently, as discussed later in this section, 
the available data were sufficient to support the establishment of 
definitive timeframes.
    Most commenters, however, were generally supportive of an approach 
that would establish timeframes for closure, whether in a tiered-like 
approach (i.e., timeframes for closure based on one or more 
characteristics of the unit) or under a ``rebuttable presumption'' 
approach, so long as the rule would provide the owner or operator a 
process or procedures to demonstrate the need for additional time. As 
explained in the NODA, such an approach could be implemented by 
establishing a presumption that facilities complete closure within a 
specified timeframe, such as five years, unless the facility could 
document that closure is not feasible to complete within the 
presumptive timeframe.
    After consideration of all of the public comments, EPA is adopting 
an approach that takes elements from two of the alternatives discussed 
in the NODA: The concept of tiered timeframes based primarily on the 
size of the surface impoundment, and the concept of a rebuttable 
presumption. The final rule establishes a presumption that the owner or 
operator must complete the closure of a CCR surface impoundment within 
five years of initiating closure activities. For CCR landfills the 
presumption is that the owner or

[[Page 21420]]

operator must complete closure within six months of initiating closure 
activities. The rule, however, provides procedures for an owner or 
operator to rebut either presumption and obtain additional time, 
provided the owner or operator can make the prescribed demonstrations. 
For CCR surface impoundments, the amount of additional time beyond the 
five years varies based on the size (using surface area acreage of the 
CCR unit as the surrogate of size) of the unit. For impoundments 40 
acres or smaller, the maximum time extension is two years. For 
impoundments greater than 40 acres, the maximum time extension is five 
two-year extensions (ten years) and the owner or operator must 
substantiate the factual circumstances demonstrating the need for each 
two year extension. For a CCR landfill, the amount of additional time 
beyond the six months does not vary according to the size of the 
landfill, rather the maximum time extension is two one-year extensions 
(two years) for any CCR landfill. The owner or operator must 
substantiate the factual circumstances demonstrating the need for each 
one-year extension.
ii. CCR Surface Impoundment Timeframes
    To develop these timeframes the Agency began by identifying the 
period of time in which most surface impoundments could feasibly 
complete closure. EPA intended this period of time to serve as the 
basis for the rebuttable presumption of the rule. As EPA recognized in 
the NODA, a timeframe that would be feasible for the largest units 
would grant more time than could be justified to complete the closure 
of smaller units. The closure of CCR units, and particularly the 
closure of CCR units that are compelled to close because they fail to 
comply with the rule's requirements (e.g., are structurally unstable or 
are contaminating groundwater), needs to occur as expeditiously as is 
feasible. While these units (and particularly the larger CCR surface 
impoundments) are in the process of closing, they continue to present 
risks to human health and the environment. On the other hand a 
presumptive time period that is feasible for a small percentage of 
units would simply result in a greater number of facilities that would 
need to obtain time extensions. It is well established that the law 
cannot compel actions that are physically impossible, ``lex non cogit 
ad impossibilia,'' and it is incumbent on EPA to develop a regulation 
that does not in essence establish such a standard.
    The available information shows that CCR surface impoundments can 
vary in size by orders of magnitude (i.e., from less than one acre to 
nearly 1,000 acres). EPA evaluated the information on the size 
distribution of CCR surface impoundments in its database of survey 
results from EPA's 2009 Information Request.\123\ Through this effort, 
EPA received a substantial amount of factual information from 240 
facilities covering 676 surface impoundments, including surface area 
information on over 650 impoundments. The database of survey responses 
shows that the median surface impoundment is approximately 14 acres in 
size, 75 percent of impoundments are 50 acres or smaller, 80 percent of 
impoundments are 66 acres or smaller, and 90 percent of impoundments 
are 111 acres or smaller.
---------------------------------------------------------------------------

    \123\ More information on EPA's Information Request, including a 
data base of survey responses, can be accessed at http://www.epa.gov/epawaste/nonhaz/industrial/special/fossil/surveys/index.htm.
---------------------------------------------------------------------------

    Available information on actual and projected timeframes needed to 
close CCR surface impoundments of varying sizes (using surface area as 
the surrogate for size) is summarized below. Much of this information 
came from public comments from utilities. The largest CCR surface 
impoundment in this data set that has actually completed closure is a 
40-acre unit that closed over a period of approximately five years 
(i.e., the surface impoundment at PPL Corporation's Martins Creek Power 
Plant).\124\ This facility closed with waste in place, and included 
installation of a final cover system. According to the facility, this 
CCR unit ceased receiving wastewater in January 2008, and the closure 
work began with dewatering the unit and preparing the revised closure 
plan and permit modification applications. Installation of the final 
cover, in addition to final soil grading and seeding of the unit was 
completed in spring 2012. By early 2013, all remaining closure actions 
were completed and state regulators issued final approvals in July 
2013. EPA gave substantial weight to this information because (1) it 
was a CCR surface impoundment--the units of greatest relevance to the 
issue at hand; (2) the closure was recently completed, and so would 
accurately reflect current and available engineering practices; and (3) 
the facility actually completed closure of the unit. See EPA-HQ-RCRA-
2012-0028-0103 and EPA-HQ-RCRA-2012-0028-0113.
---------------------------------------------------------------------------

    \124\ EPA included information on the planned closure of this 
CCR surface impoundment in the NODA. 78 FR 46945. The closure plan 
estimated that the closure process would take approximately three 
years to complete.
---------------------------------------------------------------------------

    As another example, American Electric Power (AEP) provided some 
information on the recent closure of a CCR surface impoundment in 2013. 
This 21-acre unit had been inactive for several years and was closed 
over the course of two construction seasons. The impoundment was closed 
by leaving CCR in place and installing a composite cap, in addition to 
the installation of hydraulic appurtenances to control the design storm 
events. See EPA-HQ-RCRA-2012-0028-0067.
    Cleco Corporation provided planned closure timeframes contained in 
existing permits for its CCR surface impoundments. For three of its CCR 
surface impoundments, which in aggregate totaled 66 acres, Cleco 
Corporation estimated that it could take approximately one year to 
complete closure, which would be accomplished by leaving CCR in place 
and installing a final cover system. Cleco Corporation also estimated 
that it would take approximately nine months to complete closure of two 
additional CCR surface impoundments, with an aggregate acreage of 5.5 
acres, by removing CCR from the CCR units, (i.e., clean closure of the 
units). Information on the size of any of the five CCR units was not 
provided, which complicates the Agency's ability to assess the closure 
of any of the individual CCR units. In addition, the time period 
appears to begin when dewatering operations are initiated and the 
comments do not discuss how much time may be needed to obtain any 
necessary approvals from the state prior to commencing closure 
activities. See EPA-HQ-RCRA-2012-0028-0106.
    Similarly, Xcel Energy stated in its comments to the NODA that it 
closed four CCR surface impoundments at its Northern States Power of 
Minnesota's Minnesota Valley Plant by removing all of their contents. 
See EPA-HQ-RCRA-2012-0028-0079. While the commenter did not provide any 
information on the time needed to close the four CCR units, other 
information available to the Agency indicated that closure took place 
sometime after May 2009 and was completed prior to September 2013. 
Based on information obtained from Xcel Energy in response to EPA's 
request for information from May 2009, the four CCR units at the 
Minnesota Valley Plant each have a surface area less than one acre. In 
addition, the response to the information request showed that one CCR 
surface impoundment was nearly full of ash, a second was more than half 
full, and the final two CCR units were less than one quarter full.
    In the August 2013 NODA, the Agency solicited comment on a draft 
plan to close two CCR surface

[[Page 21421]]

impoundments at Santee Cooper's Grainger Generating Station in South 
Carolina. 78 FR 46945. The plan estimated that closure of the two CCR 
units, approximately 42 and 39 acres in surface area, could be 
accomplished during a three year period. This original estimate was 
based on closing the unit with waste in place and installing a final 
cover. However, Santee Cooper has since amended its draft plan and is 
now pursuing closure by removal of CCR and transport off-site for 
either disposal or beneficial use.\125\ The revised draft envisions the 
complete removal of CCR from both CCR units and also one foot of 
underlying soil beneath the units. In total, the draft closure plan 
estimates that approximately 1.3 million cubic yards of CCR and 
underlying soil will be removed from both units--approximately 900,000 
cubic yards from one unit and 400,000 cubic yards from the second--over 
a period of six to ten years.
---------------------------------------------------------------------------

    \125\ ``Amended Closure Plan Wastewater Ash Ponds, Grainger 
Generating Station, Conway, South Carolina,'' January 2014.
---------------------------------------------------------------------------

    The Florida Electric Power Coordinating Group (FCG) claimed that, 
based on FGC member experience, closing a 30 acre CCR surface 
impoundment is expected to take approximately two years to complete, 
but provided no additional information or details. See EPA-HQ-RCRA-
2012-0028-0064.
    The Utility Solid Waste Activities Group (USWAG) provided another 
projected closure schedule for a 20 acre CCR surface impoundment 
operated by Luminant. This facility was in the process of closing the 
unit when the comments were prepared. The schedule estimated that 
completion of all closure activities, would take approximately 45 
months (3 years, 9 months) to complete. However, the commenter also 
states that, when complete, the ``full closure period will take 
approximately 84 months (seven years) due to the unique circumstances 
of that closure.'' No other information was provided on this closure to 
explain the ``unique circumstances'' that warrant such an extended 
period of time. See EPA-HQ-RCRA-2012-0028-0113.
    There is other information in these data that indicates that larger 
impoundments may be able to complete closure within approximately the 
same timeframes as smaller units. For example, the data included the 
projected closure of a 100-acre CCR surface impoundment over a four and 
one-half year period, which seems to indicate that larger units may be 
able to close in approximately the same period of time. However, the 
Agency gave substantially less weight to this information for a number 
of reasons. Most critically, this information merely demonstrated 
projected timeframes for CCR surface impoundments, not actual 
timeframes that had been achieved. In addition, for some of these data, 
it was unclear whether the circumstances that allowed for completion 
within this timeframe were generally applicable to the majority of CCR 
surface impoundments. In one instance, the commenter noted that the 
time to complete closure was shorter than would normally be expected 
because the impoundment was being closed well before it reached full 
capacity and because water in the impoundment could be pumped into an 
adjacent impoundment. The commenter also noted that the impoundment had 
been built with a leachate collection system to facilitate dewatering 
at closure. See EPA-HQ-RCRA-2012-0028-0113.
    Moreover, the majority of commenters claimed that it would take 
substantially longer than five years to close the largest impoundments. 
For example, USWAG stated that one of its members obtained ``approval 
for a closure plan for a 343-acre surface impoundment that provided for 
a twelve-year closure period to ensure adequate time to complete 
dewatering of the impoundment, assure the stability of the dewatered 
CCRs, and uniformly construct the slope of the final cover materials.'' 
No other information was provided on this closure example. See EPA-HQ-
RCRA-2009-0640-10483. USWAG also provided information on the closure of 
the CCR surface impoundment at First Energy's Little Blue Run Disposal 
Area. This 950 acre surface impoundment, which is the largest CCR 
surface impoundment in the country, has a projected closure period of 
15 years.
    Similarly, to illustrate the time required simply for earthmoving 
operations to close a large CCR surface impoundment (in their example, 
350 acres), Duke Energy Corporation estimated that the time needed in 
the schedule to deliver and place the necessary volume of materials for 
construction of the final cover and the sub-base to the cover system 
could take between nine and 12 years. This estimate is based on the 
need for approximately 10 to 11 million cubic yards of fill to 
construct and shape the sub-base of the final cover and the cover 
system itself that would require nearly 500,000 truckloads to deliver. 
See EPA-HQ-RCRA-2012-0028-0095.\126\
---------------------------------------------------------------------------

    \126\ EPA also received information from Consumers Energy 
Company on the closure of three former fly ash surface impoundments 
at the JR Whiting plant. These surface impoundments (combined) 
totaled approximately 52 acres and are scheduled to be closed with a 
final cover over an approximately 12-year period. The commenter 
claimed that the extended time for closure ``was necessary to allow 
dewatering and the filling of numerous voids, but principally to 
allow the generation of fly ash to allow the placement of 
structurally placed, low permeability ash to provide minimal 
required slopes for closure and to serve as the select layer for the 
flexible membrane liner.'' See EPA-HQ-RCRA-2012-0028-0068. 
Information on the individual size of any of the three CCR units was 
not provided in the comments, which complicates any assessment of 
the time needed to complete closure of any single CCR unit. Because 
the facility appears to be continuing to use the unit to actively 
manage waste, EPA does not consider this to be representative of a 
typical closure process.
---------------------------------------------------------------------------

    Collectively, this information formed the basis for the five year 
presumptive default. As noted the median size of CCR surface 
impoundments is approximately 14 acres, and 75 percent of impoundments 
are 50 acres or smaller. The information presented by the utilities 
documents that impoundments as large as 66 acres under normal 
circumstances can close within two to three years. EPA therefore 
expects that most, if not all, units should be able to complete closure 
within five years. For all but the very largest units, this timeframe 
would even accommodate potential delays caused by weather or any other 
unpredictable variables. This is clearly demonstrated by the examples 
presented by public comments, and by the recent example of the 40-acre 
CCR surface impoundment in Martins Creek that closed within five years.
    EPA also notes that five years is the timeframe Congress mandated 
for the completion of open dumps to close or upgrade. While the closure 
times apply generally to all units--both those whose closure is 
mandated by this final rule and those that close because the facility 
decides to do so--the statutory directive provides further support for 
EPA's decision.
    But as many commenters stated, initial estimates can and often do 
vary from actual closure times due to unforeseen or variable 
conditions. EPA acknowledges that a host of variables can, and 
frequently do, delay closure activities, such that the initial time 
estimates to complete closure of the unit are ultimately exceeded. For 
example, the 40 acre impoundment at Martins Creek Power Plant discussed 
above was initially scheduled in its closure plan to be completed 
within three years; however, closure ultimately took five years to 
complete. The additional two

[[Page 21422]]

years was due to the need to obtain approval of a modified closure plan 
from the state, as well as modifications to three permits, in addition 
to obtaining other local planning approvals. Further time was also 
needed to accommodate the public notice and comment processes for 
several of the permits and approvals.
    EPA recognizes that there are a number of unpredictable or variable 
conditions that can affect the time needed to close a CCR unit and that 
those conditions are not within the control of the owner or operator. 
For example, some states require review and approval of a closure plan 
prior to initiating of closure activities. See, for example, 25 Pa. 
Code sections 288.292(b) and 289.311(b) for CCR landfills and CCR 
surface impoundments, respectively. Another commenter noted that in 
Illinois, permits from several different authorities may need to be 
obtained to commence closure, including the Illinois Department of 
Natural Resources, the U.S. Army Corps of Engineers, and the U.S. Fish 
and Wildlife Services.
    Climate and weather can also impact the time needed to complete 
closure. For example, an unusually wet or short construction season can 
result in schedule delays; one commenter noted that in certain regions 
of the Midwest, it is possible for as much as 40 inches of rain to fall 
in a given season.
    To account for these conditions, a substantial majority of 
commenters requested that the final rule include the potential for time 
extensions, and several specifically referenced the need for a ``force 
majeure'' provision. One commenter also recommended that a ``force 
majeure'' clause specifically include delays caused by court order 
(i.e., appeals of permits issued by state agencies causing judgments in 
court). Another commenter provided an example of a ``force majeure'' 
provision that could serve as a model:

    An extension shall be granted for any scheduled activity delayed 
by an event of force majeure which shall mean any event arising from 
causes beyond the control of the owner that causes a delay in or 
prevents the performance of any of the conditions under this rule 
including but not limited to: acts of God, fire, war, insurrection, 
civil disturbance, explosion; adverse weather conditions that could 
not be reasonably anticipated causing unusual delay in 
transportation and/or field work activities; restraint by court 
order or order of public authority; inability to obtain, after 
exercise of reasonable diligence and timely submittal of all 
applicable applications, any necessary authorizations, approvals, 
permits, or licenses due to action or inaction of any governmental 
agency or authority; and delays caused by compliance with applicable 
statutes or regulations governing contracting, procurement or 
acquisition procedures, despite the exercise of reasonable diligence 
by representatives of the owner.
    Events which are not force majeure include by example, but are 
not limited to, unanticipated or increased costs of performance, 
changed economic circumstances, normal precipitation events, or 
failure by the owner to exercise due diligence in obtaining 
governmental permits or performing any other requirement of this 
rule or any procedure necessary to provide performance pursuant to 
the provisions of this rule.

    EPA agrees that the rule should include procedures to obtain 
extensions of time to complete closure of the unit, based on the 
complexity of the activity. As previously noted, the law, including a 
regulation, cannot compel the impossible. However, because the record 
demonstrates that most units, even the larger units, can close within 
that five year timeframe, the rule establishes a high threshold to 
obtain additional time. To account for those instances of true physical 
impossibility, the rule limits extensions to circumstances in which the 
owner or operator can demonstrate that the additional time is needed 
due to factors that are truly beyond the facility's control--i.e., 
could fairly be characterized as an example of ``force majeure.'' To 
obtain additional time, the owner or operator of the CCR unit must 
document in writing the exact reasons why additional time is needed. 
The regulation specifies that such reasons could include: (1) 
Complications stemming from the climate and weather, such as unusual 
amounts of precipitation or a significantly shortened construction 
season; (2) the time required to dewater a surface impoundment due to 
the volume of CCR contained in the CCR unit or the geotechnical 
characteristics of the CCR in the unit; (3) the geology and terrain 
surrounding the CCR unit will affect the amount of material needed to 
close the CCR unit; or (4) the time required or delays caused by the 
need to obtain State permits and/or to comply with other State 
requirements. These findings would need to be certified by the owner or 
operator of the unit, as well as by a qualified professional engineer.
    The final rule limits the amount of time that closure can be 
extended based on the size of the CCR unit. Specifically, the rule 
allows CCR surface impoundments 40 acres or smaller a time extension of 
up to two years, while CCR surface impoundments larger than 40 acres 
can obtain up to five two-year extensions. The 40 acre size demarcation 
is based on the available information showing that surface impoundments 
of 40 acres or smaller routinely have either completed closure or are 
projected to be able to complete closure within a timeframe shorter 
than five years. EPA expects that facilities will account for all 
potential delays that can reasonably be foreseen in planning their 
closure activities, and that this is feasible within this five year 
timeframe. Consequently the final rule restricts facilities with units 
of this size to a single extension to account for truly exception 
circumstances (e.g., Acts of God).
    The Agency also recognizes that there is increased uncertainty for 
CCR surface impoundments larger than 40 acres. First, while available 
information documents that some CCR surface impoundments larger than 40 
acres can be closed within this same five year period, the Agency has 
other information indicating that closure of units larger than 40 acres 
can be expected to take much longer than five years. For example, the 
largest surface impoundment in the country is approximately 950 acres 
and is scheduled to cease receiving CCR by December 31, 2016 and 
commence closure in 2017. The facility's projected closure period is 15 
years. However, EPA currently has no data (anecdotal or otherwise) on 
the actual timeframes in which a surface impoundment of that size has 
completed closure. Given that closure for the largest of surface 
impoundments could reasonably be expected to take more than five years 
to complete, the Agency has concluded that surface impoundments larger 
than 40 acres need to be provided with the possibility of additional 
time extensions beyond the two years provided to impoundments less than 
40 acres. Based on available information, in particular the current 
estimates of the time needed to close the largest unit in the country, 
the rule authorizes a facility to obtain a maximum of five time 
extensions, totaling as much as ten years in two year increments to 
close a CCR surface impoundment greater than 40 acres. However, the 
owner or operator must substantiate the factual circumstances 
demonstrating the need for each two-year extension.
    Several commenters also urged EPA to specify in the final rule what 
EPA intended by the phrase ``completion of closure;'' and to define the 
activities or actions the owner or operator must complete to satisfy 
the closure requirements. For purposes of this rule, closure of a CCR 
unit is complete when the unit meets all of the requirements of this 
rule and the owner or operator

[[Page 21423]]

obtains certification from a qualified professional engineer verifying 
that closure has indeed been completed, consistent with all of the 
performance standards in the rule. While EPA recognizes that under some 
state programs closure is not considered complete until the owner or 
operator receives certification from the state, this is not a 
prerequisite to completion of closure under these federal rules.
iii. Closure Timeframes for CCR Landfills
    Similar to the approach for CCR surface impoundments, EPA 
recognizes that there can be unforeseen and extraordinary circumstances 
that warrant additional time to close a CCR landfill. Accordingly, the 
rule adopts procedures analogous to those for CCR surface impoundments 
that allow the owner or operator to obtain additional time to complete 
the closure of a CCR landfill, provided the owner or operator can make 
the prescribed demonstrations. However, the amount of additional time 
the facility can obtain beyond the presumptive six month timeframe does 
not depend on the size of the landfill; rather the maximum time 
extension is two one-year extensions (two years) for any CCR landfill. 
As with the procedures for CCR surface impoundments, the owner or 
operator must substantiate the factual circumstances demonstrating the 
need for each one-year extension.
    EPA developed this timeframe based on its review of the available 
information in the record regarding the timeframes for completing the 
closure of CCR landfills, some of which is summarized below. Additional 
information may also be found in the comment response document.
    In response to the August 2013 NODA, Nebraska Public Power District 
(NPPD) provided information documenting that it completed closure of a 
10 acre CCR landfill within 180 days after the final volume of fly ash 
and bottom ash was placed in the CCR landfill. Closure was accomplished 
by leaving CCR in place and installing a final cover system. NPPD's 
comments do not indicate what year closure of this CCR landfill was 
completed. See EPA-HQ-RCRA-2012-0028-0076.
    The Florida Electric Power Coordinating Group (FCG) stated in its 
comments that FCG member experience with CCR landfill closure has 
``demonstrated the need for a period of time greater than 180 days to 
complete closure activities.'' However, the commenter did not provide 
any information indicating how long such closures actually took, nor 
any information to substantiate their claim. See EPA-HQ-RCRA-2012-0028-
0064.
    Overall, the closure of CCR landfills is less complex than the 
closure of CCR surface impoundments. Portions of the CCR landfills that 
reach final grade can be closed as other areas of the CCR landfill 
continue to receive CCR, which is typically not possible at CCR surface 
impoundments. Nor does the owner or operator need to dewater the unit, 
which appears to be the aspect of closure most likely to be a source of 
unanticipated circumstances. Finally, there is substantially less 
uncertainty with respect to the timeframes to complete the closure of 
CCR landfills, which are not all that different (in this respect) than 
landfills containing other forms of solid or hazardous waste. EPA 
therefore has greater confidence that a fixed period of two years will 
be adequate to account for the vast majority of circumstances.
c. Alternative Closure Requirements
    The Agency is finalizing alternative closure requirements in two 
narrow circumstances for a CCR landfill or CCR surface impoundment that 
would otherwise have to cease receiving CCR and close, consistent with 
the requirements of Sec.  257.101(a), (b)(1), or (d). The first is 
where the owner or operator can certify that CCR must continue to be 
managed in that CCR unit due to the absence of both on-site and off-
site alternative disposal capacity. Sec.  257.103(a). The second is 
where the owner or operator of a facility certifies that the facility 
will cease operation of the coal-fired boilers no later than the dates 
specified in the rule, but lacks alternative disposal capacity in the 
interim. Sec.  257.103(b). Under either of these alternatives, CCR 
units may continue to receive CCR under the specified conditions 
explained below. In addition, under either alternative, the owner or 
operator must continue to comply with all other requirements of the 
rule, including the requirement to conduct any necessary corrective 
action.
    1. No alternative CCR disposal capacity (Sec.  257.103(a)).
    The Agency recognizes that the circumstance may arise where a 
facility's only disposal capacity, both on-site and off-site, is in a 
CCR unit that has triggered the closure requirements in Sec.  
257.101(a), (b)(1), or (d). As a result, the facility may be faced with 
either violating the closure requirements in Sec.  257.101 by 
continuing to place CCR in a unit that is required to close, or having 
to cease generating power at that facility because there is no place in 
which to dispose of the resulting waste. For example, while it is 
possible to transport dry ash off-site to alternate disposal facility 
that simply is not feasible for wet-generated CCR. Nor can facilities 
immediately convert to dry handling systems. As noted previously, the 
law cannot compel actions that are physically impossible, and it is 
incumbent on EPA to develop a regulation that does not in essence 
establish such a standard.
    Should a facility choose to comply with the regulation and stop 
generating power, there would be significant risks to human health that 
would arise if a community would be left without power for an extended 
period of time. As information in the record demonstrates, obtaining 
alternative capacity can sometimes require a substantial amount of time 
(e.g., if the facility needs to construct alternative capacity, 
including potentially the need to locate an alternative site or 
purchase additional property). EPA recognizes that there are also 
significant risks to human health and the environment, as demonstrated 
throughout this preamble, from a leaking or improperly sited CCR unit, 
and that these risks justify requiring those units to either retrofit 
to meet the federal criteria established in the final rule or close. 
EPA also acknowledges that in the interim period while the owner or 
operator seeks to obtain additional capacity, the risks associated with 
the continued use of these units will be significant. However, the 
Agency believes that the risks to the wider community from the 
disruption of power over the short-term outweigh the risks associated 
with the increased groundwater contamination from continued use of 
these units. This conclusion is further buttressed by the fact that 
during this interim period the risks associated with allowing these 
units to continue to receive CCR are mitigated by all of the other 
requirements of the rule with which the facility must continue to 
comply, including the requirements to continue groundwater monitoring 
and corrective action.
    Under Sec.  257.103(a)(1), a CCR unit that would otherwise be 
required to cease receiving CCR under Sec.  257.101(a), (b)(1), or (d), 
may continue to receive CCR provided the owner or operator certifies 
that the CCR generated at that facility must continue to be managed in 
that unit due to the absence of alternative disposal capacity both on-
site and off-site. The rule also requires the owner or operator to 
document this claim, and the claim must be based on the real absence of 
an alternative and not justified based on the costs or inconvenience of 
alternative disposal capacity. Sec.  257.103(a)(1)(i). The owner

[[Page 21424]]

or operator must also remain in compliance with all other requirements 
of this rule, including the requirement to take any necessary 
corrective action. Sec.  257.103(a)(1)(ii). Because this alternative is 
only available as long as the absence of disposal capacity exists, the 
owner or operator must document its efforts to obtain additional 
capacity. If any additional capacity is identified, the owner or 
operator must arrange to use it as soon as is feasible. Sec.  
257.103(a)(1)(iii). The owner or operator is also required to prepare 
an annual progress report documenting the continued absence of disposal 
capacity and must also document the progress made toward developing 
alternative capacity. Sec.  257.103(a)(1)(iv).
    Once alternative disposal capacity is available, the CCR unit must 
cease receiving CCR and must initiate closure following the timeframes 
in Sec.  257.102(e) and (f). Finally, if the owner or operator has not 
identified alternative capacity within five years after the initial 
certification the CCR unit subject to this section must cease receiving 
CCR and must initiate closure following the timeframes in Sec.  
257.102(e) and (f). As discussed elsewhere in this preamble, several 
commenters provided information to document the length of time needed 
to obtain additional capacity. Based on this information, the five year 
timeframe provided for under this alternative is expected to provide 
sufficient time to obtain alternative disposal capacity and to avoid 
the consequences of a forced immediate closure of a power plant.
    2. Permanent cessation of a coal-fired boiler by a date certain. 
(Sec.  257.103(b)).
    Under this provision, the Agency addresses the circumstance where a 
facility's only disposal capacity, both on-site and off-site, is in a 
CCR unit that has triggered the closure requirements in Sec.  
257.101(a), (b)(1), or (d), but the owner or operator of coal-fired 
power plant has decided to permanently cease operation of that plant 
within one of two timeframes specified in the regulation. For the same 
reasons discussed immediately above, EPA has concluded that the 
provisions of Sec.  257.103(b) represent the most reasonable balance 
between the competing risks.
    Additionally, EPA anticipates that some owners or operators will 
decide to permanently cease operation of a coal-fired power plant in 
response to the combined effects of new and/or existing statutory or 
regulatory requirements promulgated under the Clean Air Act and under 
the Clean Water Act (e.g. the proposed Effluent Limitations Guidelines 
and Standards for the Steam Electric Power Generating Point Source 
Category. See 78 FR 34442, in combination with market dynamics. As 
discussed earlier in this preamble, RCRA section 1006(b) directs EPA to 
integrate the provisions of RCRA for purposes of administration and 
enforcement and to avoid duplication, to the maximum extent 
practicable, with the appropriate provisions of other EPA statutes, 
including the CAA and the CWA. As noted earlier, section 1006(b) 
conditions EPA's authority to reduce or eliminate RCRA requirements on 
the Agency's ability to demonstrate that the integration meets RCRA's 
protectiveness mandate (42 U.S.C. 6005(b)(1)). See Chemical Waste 
Management v. EPA, 976 F.2d 2, 23, 25 (D.C. Cir. 1992). The provisions 
of Sec.  257.103(b) are fully consistent with the direction in section 
1006(b) to account for the provisions of other EPA statutes which may 
lead an owner or operator to close a coal-fired power plant.
    EPA has also concluded that the provisions of Sec.  257.103(b) meet 
RCRA's protectiveness mandate. As stated above, EPA recognizes that 
there are long-term risks to human health and the environment, as 
demonstrated throughout this preamble, from a leaking CCR unit and 
those risks justify requiring those units to either meet the federal 
criteria established in this rule or close. However, the risks 
associated with allowing these units to continue to receive CCR are 
mitigated by the requirement that the facility must comply with all 
other requirements of the rule, including initiating groundwater 
monitoring and corrective action where necessary. And a critical factor 
is that facilities that choose to rely on this alternative will be 
required to complete closure of their disposal unit in an expedited 
timeframe. Thus, the risks from these units will be fully addressed 
sooner. Consequently, while over the short term the risks will be 
higher, overall, the risks will be at least equivalent to, or 
potentially lower than if the CCR unit had closed in accordance with 
the normal closure timeframes.
    Under Sec.  257.103(b)(1), a CCR unit that would otherwise be 
required to cease receiving CCR under Sec.  257.101(a), (b)(1), or (d), 
may continue to receive CCR provided the owner or operator of the 
facility certifies that the facility will cease operation of the coal-
fired boilers within the timeframes specified in paragraphs (b)(2) 
through (b)(4) and that the CCR generated at that facility (before the 
plant ceases to operate) must continue to be managed in that unit due 
to the absence of alternative disposal capacity both on-site and off-
site. The rule also requires the owner or operator to document the 
facts that support this claim. The regulation specifies that the claim 
must be based on the real absence of alternative disposal capacity, and 
not justified based on the costs or inconvenience of alternative 
disposal capacity. Sec.  257.103(b)(1)(i). The owner or operator must 
also remain in compliance with all other requirements of this rule, 
including the requirement to take any necessary corrective action. 
Sec.  257.103(b)(1)(ii). The owner or operator is also required to 
prepare an annual progress report documenting the continued absence of 
disposal capacity and must also document the progress made toward the 
closing of the coal-fired boiler. Sec.  257.103(b)(1)(iii).
    Under Sec.  257.103(b)(1), the owner or operator does not need to 
demonstrate any efforts to develop alternative capacity because of the 
impending closure of the power plant itself.
    Consistent with the general timeframes provided for the closure of 
CCR surface impoundments, EPA has established different timeframes 
based on the size of the CCR unit. Under Sec.  257.103(b)(2), where the 
disposal unit is a CCR surface impoundment 40 acres or smaller in size, 
the coal-fired boiler must cease operation and the disposal unit must 
have completed closure within 8.5 years of the publication date of the 
rule. Where the disposal unit is a CCR surface impoundment larger than 
40 acres in size, the coal-fired boiler must cease operation and the 
disposal unit must have completed closure within 13.5 years of the 
publication date of the rule. Sec.  257.103(b)(3). Finally, under Sec.  
257.103(b)(4), where the disposal unit is a CCR landfill, the coal-
fired boiler must cease operation and the disposal unit must have 
completed closure within 6 years of the publication date of the rule. 
These timeframes were selected to ensure that closure of these units 
will be completed in a measurably shorter timeframe, and that overall 
the risks will be lower, or at least equivalent to, the level of risk 
that would be achieved under the rule's ``standard'' closure 
provisions.
5. Notation on the Deed to Property
    The proposed rule would have required, following closure of the CCR 
unit, the owner or operator to record a notation on the deed or some 
other instrument normally examined during a title search. This notation 
would notify any potential purchaser in perpetuity that the property 
has been used as a CCR landfill or CCR surface impoundment and that use 
of the land is restricted under the rule's post-closure care 
provisions. After the

[[Page 21425]]

notation was completed, the proposed rule would have required the owner 
or operator to notify the state that the notation has been recorded and 
a copy has been placed in the facility's operating record and on its 
publicly accessible internet site. In addition, the Agency solicited 
public comment on adding a provision to the rule to allow removal of 
the deed notation once all CCR are removed from the CCR unit, and 
notification is provided to the state of this action. The EPA solicited 
comment on this potential approach as a way to create a further 
incentive for clean closure of the facility. 75 FR at 35208-09. The 
proposal further encouraged commenters who are interested in supporting 
such an option to suggest alternatives to state oversight to provide 
for facility accountability.
    EPA received few public comments on the proposed requirement to 
record a deed notation to the property (or some other instrument that 
is normally examined during title search). One commenter provided 
general support for the proposed requirement to record a deed notation 
to the property. Another commenter urged EPA to ensure that any deed 
notation requirements should not interfere or conflict with existing 
state property laws that provide for environmental covenants.
    EPA did receive several comments in response to the Agency's 
solicitation of comment on adding a provision to the rule to allow 
removal of the deed notation when all CCR are removed from the 
facility, and notification is provided to the state of this action. One 
commenter supported the addition of this provision, stating that the 
licensure requirements of the Professional Engineer provide an 
assurance of integrity because the Professional Engineer would be 
required to verify that closure has been completed in accordance with 
the closure plan. This commenter also stated that it would be 
sufficient to allow removal of a deed notation upon an application to 
the state agency supported by a declaration of a licensed professional, 
subject to state agency review and approval. Another commenter 
supported providing the incentive for clean closure and allowing the 
facility to demonstrate the ``cleanliness of the closure.'' The 
commenter also recommended that the information provided by the 
facility should be followed by a review from an independent third party 
with knowledge of the industry and associated environmental issues.
    After considering comments, the final rule requires an owner or 
operator to record a notation on the deed or some other instrument 
normally examined during a title search. This notation notifies any 
potential purchaser in perpetuity that the property has been used as a 
CCR landfill or CCR surface impoundment and that use of the land is 
restricted under the rule's post-closure care provisions. See Sec.  
257.102(i). In response to the commenter that urged EPA to ensure that 
any deed notation requirements should not interfere or conflict with 
existing state property laws, the Agency has no information that the 
proposed requirement would create such a conflict. In addition, the 
commenter did not provide any information or suggest that EPA's 
proposed approach would actually interfere or conflict with existing 
state property laws. Therefore, the Agency is finalizing the deed 
notation requirement as proposed.
    In addition, regarding the Agency's solicitation of comment on 
adding a provision to the rule to allow removal of the deed notation 
when all CCR are removed from the facility, as discussed in Unit VI.M.2 
of this preamble, the final rule adopts the proposal to allow the owner 
or operator to remove the deed notation required under Sec.  
257.102(i)(4), upon certification that clean closure has been 
completed. The rationale for this decision is discussed in that unit of 
the preamble.
6. Notification of Intent To Close and Certification of Closure 
Completion
    The Agency proposed to require owners or operators to notify the 
state that a notice of intent to close a CCR unit has been placed in 
the facility's operating record and on the publicly accessible internet 
site. This notification had to be completed prior to beginning closure 
of the CCR unit. Following closure of a CCR unit, the proposed rule 
would also have required the owner or operator to obtain a 
certification from an independent registered professional engineer 
verifying that closure has been completed in accordance with the 
written closure plan. As proposed, this certification would be placed 
in the facility's operating record and on the publicly accessible 
Internet site.
    The Agency received no public comments on the proposed requirements 
to develop a notification of intent to close or the certification of 
completion of closure. Therefore, the Agency is finalizing these 
requirements as proposed. See Sec.  257.102(g) and (h).
7. Post-Closure Care Plan
    The Agency proposed to require that the owners or operators of CCR 
landfills and CCR surface impoundments prepare a written post-closure 
care plan describing how the CCR unit would be maintained after 
closure. See proposed Sec.  257.101(c). The proposal also identified 
the minimum information necessary to include in the post-closure care 
plan. This information included: (1) A description of the monitoring 
and maintenance activities for the CCR unit and the frequency at which 
these activities would be performed; (2) the name, address, and 
telephone number of the person or office to contact about the facility 
during the post-closure care period; and (3) a description of the 
planned uses of the property during the post-closure care period.
    The proposed rule further provided that the post-closure use of the 
property shall not disturb the integrity of the final cover, liner(s), 
or any other components of the containment system, or the function of 
the post-closure monitoring systems unless necessary to comply with the 
requirements of the rule. The proposal would have allowed a disturbance 
if the owner or operator of the CCR unit demonstrated that disturbance 
of the final cover, liner, or other component of the containment 
system, including any removal of CCR, would not increase the potential 
threat to human health or the environment. A professional engineer 
would have been required to certify such a demonstration.
    The Agency received no significant comments on the proposed post-
closure care requirements. The Agency's responses to these comments are 
addressed in the closure comment response document, which is available 
in the rulemaking docket. Therefore, the Agency is finalizing these 
requirements substantially as proposed. See Sec.  257.102(g) and (h).
8. Post-Closure Care Activities
    Following closure of a CCR landfill or CCR surface impoundment, EPA 
proposed that the owner or operator would be required to conduct post-
closure care of the closed unit. At a minimum, the proposal would have 
required the owner or operator to conduct at least the following: (1) 
Maintain the integrity and effectiveness of any final cover, including 
making repairs to the final cover to correct the effects of settlement, 
subsidence, erosion, or other events, and preventing run-on and run-off 
from eroding or otherwise damaging the final cover; (2) maintain the 
integrity and effectiveness of the leachate collection and removal 
system and operating the leachate collection and removal system in 
accordance with applicable requirements under the design criteria for 
such systems; and (3) maintain the groundwater monitoring system in

[[Page 21426]]

accordance with applicable requirements under the groundwater 
monitoring and corrective action rule provisions.
    EPA received few public comments on the proposed activities to 
conduct during the post-closure care period. These commenters were 
supportive of the activities and specifically urged the rule to require 
the monitoring of groundwater throughout the post-closure care period. 
The Agency received no comments opposing the proposed post-closure care 
activities. Therefore, EPA is finalizing the same post-closure care 
activities in this rule. See Sec.  257.104(b). In addition, consistent 
with the proposal, the rule clarifies that certain CCR units are not 
subject to these post-closure care activities. Specifically, owners or 
operators that elect to close a CCR unit by removing CCR (i.e., clean 
close the CCR unit) are not subject to any post-closure care 
requirements. See Sec.  257.104(a)(2) and Unit M.2 of this preamble. In 
addition, owners or operators of inactive CCR surface impoundments that 
elect to complete closure of the unit within 30 months of the rule's 
effective date are not subject to any post-closure care requirements. 
See Sec.  257.104(a)(3).
9. Length of Post-Closure Care Period
    The Agency proposed that the owner or operator of a CCR unit 
conduct post-closure care for 30 years. EPA also proposed to allow 
utilities to conduct post-closure care for a decreased length of time 
if the owner or operator demonstrates that the reduced period is 
sufficient to protect human health and the environment. The owner or 
operator would have been required to have this demonstration certified 
by a professional engineer, in addition to complying with all of the 
notification and posting requirements under the proposed rule. The 
proposed rule would also have allowed an increase in the post-closure 
care period if the owner or operator of the CCR unit determined that it 
is necessary to protect human health and the environment. EPA also 
recognized in the proposed rule 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 the 
Agency also recognized that there is no set length of time for post-
closure care that will be appropriate for all possible sites, and all 
possible conditions. Therefore, EPA solicited comment on alternative 
methods to account for different conditions, yet still provide methods 
of oversight to assure facility accountability.
    Some commenters supported the proposed approach because it provided 
flexibility to increase or decrease the post-closure care period of 30 
years. EPA also received comments from a number of states documenting 
the current state requirements; some states require a post-closure care 
period of less than 30 years, some require 30 years, and one state 
currently requires 40 years for CCR units. Other commenters opposed the 
shortening of the 30-year period without state involvement and 
approval.
    After considering public comments, and in a departure from the 
proposed rule, the Agency is requiring that post-closure care be 
conducted for a minimum of 30 years. EPA is making this change due to 
the lack of guaranteed state oversight for this rule. The Agency has 
concluded that providing the owner or operator the flexibility to 
shorten the post-closure care period is no longer appropriate, 
particularly given the flexibility being provided for the selection of 
a final cover system or alternative final cover system. As discussed in 
Unit M.3 above, the information available to the Agency supports the 
need to proceed cautiously. By not allowing the post-closure care 
period to be shortened, EPA better ensures that the final cover system 
will be properly maintained. In addition, a mandatory 30 year period 
ensures that if problems do arise with respect to a final cover system, 
the groundwater monitoring and corrective action provisions of the rule 
will detect and address any releases from the CCR unit, at least during 
the post-closure care period.
10. Notification of Completion of Post-Closure Care Period
    The Agency proposed to require owners or operators of CCR units to 
notify the state that a notice of completion of the post-closure care 
period has been placed in the facility's operating record and on the 
publicly accessible Internet site. The proposed approach would have 
required the owner or operator to obtain a certification from an 
independent registered professional engineer verifying that post-
closure care has been completed in accordance with the written post-
closure care plan.
    The Agency received no public comments on the proposed requirement 
to develop a notification of completion of the post-closure care 
period. Therefore, the Agency is finalizing these requirements as 
proposed. See Sec.  257.104(e).

N. Recordkeeping, Notification and Posting of Information to the 
Internet

    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 regulatory requirements by providing for state 
and public notifications of the third party certifications, as well as 
requiring a robust set of other information that documents the 
decisions made or actions taken to comply with the technical 
requirements of the rule. Consistent with the proposed rule, owners or 
operators of CCR units are required to document how the various 
provisions of the rule have been met by placing information (e.g., 
plans, records, notifications, reports) in the operating record and 
providing notification of these actions to the State Director/or 
appropriate Tribal authority. The owner or operator is also required to 
establish and maintain a publicly accessible Internet site that posts 
documentation that has, in many instances, also been entered into the 
operating record. The owner or operator is required to maintain a copy 
of the current Emergency Action Plan, the current fugitive dust control 
plan, and the current written closure plan as long as the facility 
remains active. EPA believes that the establishment and maintenance of 
this information in both the operating record and on a publicly 
accessible Internet site is appropriate so as to allow states and 
citizens access to all of the information necessary to show that the 
rule has been implemented in accordance with the regulatory 
requirements.
    With regard to the specific recordkeeping and reporting 
requirements outlined in the proposal, the Agency received very little 
comment. Commenters were primarily concerned not with the specific 
recordkeeping requirements but rather how the recordkeeping 
requirements aligned with the overall approach of the RCRA subtitle D 
regulatory scheme. These comments and the Agency's responses are 
discussed in Unit V of this preamble.
    The combined mechanisms of recordkeeping, notifications, and 
maintaining a publicly accessible Internet site will serve to provide 
interested parties with the information necessary to determine whether 
the owner or operator is implementing and is operating in accordance 
with the requirements of the rule. As stated in the proposal and 
reiterated here, EPA believes that it cannot conclude that the RCRA 
subtitle D regulations will ensure there is no reasonable probability 
of

[[Page 21427]]

adverse effects on health or the environment, unless there are 
mechanisms for states and citizens to monitor the situation, such as 
when groundwater monitoring shows exceedances above the groundwater 
protection standard specified in the rule, so they can determine when 
intervention is appropriate. EPA also believes that the recordkeeping 
and notification requirements will minimize the danger of owners or 
operators abusing the self-implementing system being established in 
this rule through increased transparency and by facilitating the 
citizen suit enforcement provisions applicable to the rule.
    In contrast to the proposed rule, the Agency has identified for 
ease of implementation each recordkeeping, notification and Internet 
posting required in this rule. The proceeding section provides a 
summary of the requirements for each reporting mechanism.
1. Recordkeeping Requirements
    This rule requires the owner or operator of a CCR landfill or CCR 
surface impoundment and any lateral expansion to maintain files of all 
required information (e.g., demonstrations, plans, notifications, and 
reports) that supports the implementation of this rule in an operating 
record located at the facility. Each file must be maintained in the 
operating record for a period of at least five years following 
submittal of the file into the operating record. In certain instances, 
however, files must be maintained until the CCR unit completes closure. 
For example, the initial and periodic structural stability assessments 
as required under section Sec.  257.73(d) and Sec.  257.74(d) must be 
maintained for five years consistent with the timeframe for periodic 
reassessments. Whereas, information on the construction of a CCR 
surface impoundment must be maintained until the CCR unit completes 
closure (see 257.73(c) and 257.102.) These timeframes are generally 
consistent with the timeframes required for maintaining hazardous waste 
compliance records under subtitle C of RCRA and with the timeframes 
outlined in the proposed subtitle C option for the regulation of CCR. 
(See specifically 40 CFR 264.73 and 265.73.)
    Owners or operators with more than one CCR unit may elect to 
consolidate all files into one operating record provided that each unit 
is identified and files for that unit are maintained separately in 
different sections of the operating record. The owner or operator of 
the CCR unit must place files documenting compliance with the location 
restrictions; design criteria; operating criteria; groundwater 
monitoring and corrective action; closure and post closure care, into 
the operating record, with the specific documentation requirements 
found in Sec.  257.105. In the development of this final rule, the 
Agency has included in the regulatory language a comprehensive listing 
of each recordkeeping and notification required by the rule. The Agency 
anticipates that this effort will facilitate owners or operators 
efforts in complying with the reporting provisions of the rule, and 
will provide other interested parties with a guide to the reporting 
provisions of the rule.
2. Notification Requirements
    As previously discussed, owners or operators are required to notify 
State Directors and/or the appropriate Tribal authority when specific 
documentation has been placed in the operating record and on the owner 
or operator's publicly accessible Web site. In most instances these 
notifications must be certified by a qualified professional engineer 
and may, in certain instances will be accompanied with additional 
information and or data supporting the notification. For example under 
Sec.  257.106(f)(1), within 60 days of commencing construction of a new 
CCR unit, a notification of the availability of the design criteria 
specified under Sec.  257.105(f)(1) or (f)(3) in the operating record 
and on the owner or operator's publicly accessible Internet site. If 
however, the owner or operator of the CCR units elects to install an 
alternative composite liner, the owner or operator must also submit to 
the State Director and/or appropriate Tribal authority a copy of the 
alternative composite liner design which has been certified by a 
qualified professional engineer.
    Notification requirements can be found in Sec.  257.106, and are 
required for location criteria, design criteria, operating criteria, 
groundwater monitoring and corrective action and closure and post 
closure care.
3. Publicly Accessible Internet Site Requirements
    The Agency is finalizing, as proposed a requirement for owners and 
operators of any CCR unit to establish and maintain a publicly 
accessible Internet site, titled ``CCR Rule Compliance Data and 
Information.'' As with the operating record, owners or operators that 
maintain multiple CCR units may elect to use one Internet site in order 
to comply with these requirements, provided that the Web site clearly 
and distinctly identifies information from each of the CCR units by 
name and location. Unless provided otherwise in the rule, information 
posted to the Internet site must be available for a period no less than 
three years from the initial posting date. Posting of information must 
be completed no later than 30 days from submittal of the information to 
the operating record. This timeframe is consistent with the 
notification requirements of the rule. As with the other criteria in 
this section, Internet postings are required for various elements 
identified in the following sections: Location restrictions; design 
criteria; operating criteria; groundwater monitoring and corrective 
action; closure and post closure care. These requirements are 
enforceable by citizen suits.

VII. Summary of Major Differences Between the Proposed and Final Rules

    The basic regulatory framework outlined in the proposed rule under 
the subtitle D option, is being adopted in this final rule for the 
regulation of CCR landfills and CCR surface impoundments and any 
lateral expansion. However, as discussed in Unit VI of this document, 
the Agency has made a number of revisions to several of the provisions 
in the proposed rule, including (1) the timeframes for closure; (2) 
locations restrictions--placement above the uppermost aquifer; (3) the 
use of an alternative composite liner design; (4) revisions to align 
the structural stability criteria with the experience and data 
generated by the Assessment Program; and (5) air criteria. These 
changes have been made in response to public comments and additional 
information collected and analyses conducted by EPA in the course of 
responding to those comments. These are discussed in greater detail 
below. Under the proposed rule, all new CCR landfills and all CCR 
surface impoundments that had not completed closure would be required 
to retrofit to a composite liner or close within five years. However, 
after reviewing comments and further evaluation, the Agency has 
concluded that this regulatory approach was unnecessary in light of the 
protections afforded by the other technical provisions of the rule 
(e.g., groundwater monitoring, corrective action). In the final rule, 
EPA is allowing unlined CCR surface impoundments to continue to operate 
for the remainder of the active life, provided that the facility 
documents through groundwater monitoring that the CCR surface 
impoundment is not contaminating groundwater. However, if groundwater

[[Page 21428]]

monitoring at the facility demonstrates that the unlined CCR surface 
impoundment has exceeded any groundwater protection standard, the owner 
or operator must initiate corrective action, and either remove all CCR 
from the unit and install a composite liner (i.e., ``retrofit'') or 
close within five years. In a departure from the proposed rule, CCR 
surface impoundments less than 40 acres may receive one two-year 
extension, providing for a maximum of seven years to complete closure. 
Units greater than 40 acres may receive up to five two-year extensions 
providing a maximum of 15 years to complete closure. These units are 
also eligible for alternative closure timeframes to account for site 
specific operational constraints.
    In addition, under the proposed rule, CCR surface impoundments that 
had not closed in accordance with the rule would be subject to all the 
provisions of the rule. After further evaluation, EPA has revised the 
provision to allow an inactive CCR surface impoundment three years from 
publication of the rule in the Federal Register to complete closure. 
Owners or operators of inactive CCR surface impoundments that have not 
completed closure within this timeframe are subject to all the 
applicable requirements of the rule.
    In response to comment and upon further evaluation the Agency is 
amending the location restriction relating to the placement of the CCR 
unit above the natural water table. Under the proposal, new landfills, 
any CCR surface impoundment, and all lateral expansions would have been 
required to have a base located a minimum of two feet above the upper 
limit of the natural water table. In the final rule, the Agency has 
amended this requirement to require that new CCR landfills and all CCR 
surface impoundments, and all lateral expansions be constructed with a 
base no less than 1.52 meters (five feet) above the uppermost aquifer 
or must demonstrate that there will not be an intermittent, recurring, 
or sustained hydraulic connection between any portion of the base of 
the CCR unit and the uppermost aquifer due to normal fluctuations in 
groundwater elevations (including the seasonal high water table.) EPA 
has made this change in response to comments and further evaluation 
demonstrating that this standard is the minimum distance necessary to 
demonstrate that no reasonable probability of adverse effects on human 
health and the environment will occur.
    EPA proposed to require all new CCR landfills, CCR surface 
impoundments and any lateral expansion to be constructed with a 
composite liner. A composite liner was defined as a system consisting 
of two components; the upper component consisting of a minimum 30-mil 
FML and the lower component consisting of at least two feet of 
compacted soil. Based on public comments and further evaluation, the 
Agency is finalizing a new requirement that allows an owner or operator 
to install an alternative composite liner provided it meets the 
performance standard established in the rule. EPA has concluded that 
this alternative composite liner affords the same protection to 
groundwater resources as a composite liner.
    Under the proposed rule, all CCR landfills and CCR surface 
impoundments would have been required to manage fugitive dusts in a 
manner not to exceed 35 [mu]g/m3. The proposal also required owners or 
operators to control the wind dispersal of dusts consistent with the 
standard, and to document the measures taken to comply with the 
requirements. In response to comments and upon further evaluation, the 
Agency has removed the numerical standard of 35 [mu]g/m3 from the rule 
and is establishing a performance standard for fugitive dust control. 
This standard requires owners or operators of any CCR unit to adopt 
measures that will effectively minimize CCR from becoming airborne at 
the facility. The Agency considers this standard to be generally 
consistent with the proposed rule with the added advantage of allowing 
for flexibility in achieving compliance. The owner or operator must 
also prepare an annual CCR fugitive dust control report that describes 
actions taken by the owner or operator to control CCR fugitive dust and 
to present a record of all citizen complaints during the previous year, 
as well as a summary of the corrective action measures taken.

VIII. Implementation Timeframes for Minimum National Criteria and 
Coordination With Steam Electric ELG Rule

    The final rule generally establishes timeframes for the technical 
criteria based on the amount of time determined to be necessary to 
implement the requirements (e.g., installing the groundwater monitoring 
wells). In establishing these timeframes, EPA also accounted for other 
Agency rulemakings that may affect owners or operators of CCR units, 
namely the Effluent Limitations Guidelines and Standards for the Steam 
Electric Power Generating Point Source Category (ELG) (78 FR 34432 
(June 7, 2013)) and the Carbon Pollution Emission Guidelines for 
Existing Stationary Sources: Electric Utility Generating Units (Clean 
Power Plan) (79 FR 34830 (June 18, 2014)). Specifically, the 
implementation timeframes in this rule will not require owners or 
operators of CCR units to make decisions about those CCR units without 
first understanding the implications that such decisions would have for 
meeting the requirements of each rule. For example, this final rule 
requires the closure and post-closure plans to be prepared following 
the anticipated publication of the ELG and Clean Power Plan final rules 
so that owners or operators of CCR units can take into consideration 
those final rules as they prepare the closure and post-closure care 
plans.
    This is also particularly true in the situation where the minimum 
criteria in the CCR rule could potentially require a surface 
impoundment to either undergo RCRA closure or retrofit with a composite 
liner. A decision on what action to take with that unit may ultimately 
be directly influenced by the requirements of the ELG rule; for 
example, if the final ELG rule requires a conversion to dry handing of 
fly ash, then it may not make economic sense for an electric utility to 
retrofit a surface impoundment that contains wet-handled fly ash since 
it would be required to cease that practice under the ELG rule. Thus, 
under the final timeframes in this rule, any such decision will not 
have to be made by the owner or operator of a CCR unit until well after 
the ELG rule is final and the regulatory requirements are well 
understood. In this example, the earliest date that a CCR surface 
impoundment may be triggered into a retrofit or closure decision is 
approximately February 2017 (the exact date would be 24 months 
following publication of this final rule), which would apply to a CCR 
surface impoundment that fails to achieve minimum safety factors for 
the CCR unit. This is due to the fact that the owner or operator must 
complete the initial safety factor assessment within 18 months of the 
publication of this rule plus an additional six months to initiate 
closure of the CCR unit if the minimum factors or safety are not 
achieved. The ELG rule is scheduled to be finalized in September 2015 
and its effective date is 60 days following its publication. Thus, 
there is ample time for the owners and operators of CCR units to 
understand the requirements of both regulations and to make the 
appropriate business decisions.
    The tables below summarize the implementation timeframes for the 
minimum criteria for existing CCR

[[Page 21429]]

surface impoundments and for existing CCR landfills being promulgated 
in this rule.

   Implementation Timeframes for the Minimum Criteria for Existing CCR
                          Surface Impoundments
------------------------------------------------------------------------
                                  Implementation
                                timeframe (number      Description of
          Requirement            of months after     requirement to be
                                  publication of         completed
                                      rule)
------------------------------------------------------------------------
Location Restrictions (Sec.     42 months........  --Complete
 257.60-Sec.   257.64).                             demonstration for
                                                    placement above the
                                                    uppermost aquifer.
                                                   --Complete
                                                    demonstrations for
                                                    wetlands, fault
                                                    areas, seismic
                                                    impact zones, and
                                                    unstable areas.
Design Criteria (Sec.           18 months........  --Document whether
 257.71).                                           CCR unit is either a
                                                    lined or unlined CCR
                                                    surface impoundment.
Structural Integrity (Sec.      8 months.........  --Install permanent
 257.73).                                           marker.
                                18 months........  --Compile a history
                                                    of construction,
                                                    complete initial
                                                    hazard potential
                                                    classification
                                                    assessment, initial
                                                    structural stability
                                                    assessment, and
                                                    initial safety
                                                    factor assessment.
                                24 months........  --Prepare emergency
                                                    action plan.
Air Criteria (Sec.   257.80)..  6 months.........  --Prepare fugitive
                                                    dust control plan.
Hydrologic and Hydraulic        18 months........  --Prepare initial
 Capacity (Sec.   257.82).                          inflow design flood
                                                    control system plan.
Inspections (Sec.   257.83)...  6 months.........  --Initiate weekly
                                                    inspections of the
                                                    CCR unit.
                                6 months.........  --Initiate monthly
                                                    monitoring of CCR
                                                    unit
                                                    instrumentation.
                                9 months.........  --Complete the
                                                    initial annual
                                                    inspection of the
                                                    CCR unit.
Groundwater Monitoring and      30 months........  --Install the
 Corrective Action (Sec.                            groundwater
 257.90-Sec.   257.98).                             monitoring system;
                                                    develop the
                                                    groundwater sampling
                                                    and analysis
                                                    program; initiate
                                                    the detection
                                                    monitoring program;
                                                    and begin evaluating
                                                    the groundwater
                                                    monitoring data for
                                                    statistically
                                                    significant
                                                    increases over
                                                    background levels.
Closure and Post-Closure Care   18 months........  --Prepare written
 (Sec.   257.103-Sec.                               closure and post-
 257.104).                                          closure care plans.
Recordkeeping, Notification,    6 months.........  --Conduct required
 and Internet Requirements                          recordkeeping.
 (Sec.   257.105-Sec.                              --Provide required
 257.107).                                          notifications.
                                                   --Establish CCR
                                                    website.
------------------------------------------------------------------------


                  Implementation Timeframes for the Minimum Criteria for Existing CCR Landfills
----------------------------------------------------------------------------------------------------------------
                                       Implementation timeframe (number of months    Description of requirement
             Requirement                       after publication of rule)                  to be completed
----------------------------------------------------------------------------------------------------------------
Location Restrictions (Sec.           42 months...................................  --Complete demonstration for
 257.64).                                                                            unstable areas.
Air Criteria (Sec.   257.80)........  6 months....................................  --Prepare fugitive dust
                                                                                     control plan.
Run-On and Run-Off Controls (Sec.     18 months...................................  --Prepare initial run-on and
 257.81).                                                                            run-off control system
                                                                                     plan.
Inspections (Sec.   257.83).........  6 months....................................  --Initiate weekly
                                                                                     inspections of the CCR
                                                                                     unit.
                                      9 months....................................  --Complete the initial
                                                                                     annual inspection of the
                                                                                     CCR unit.
Groundwater Monitoring and            30 months...................................  --Install the groundwater
 Corrective Action (Sec.   257.90-                                                   monitoring system; develop
 Sec.   257.98).                                                                     the groundwater sampling
                                                                                     and analysis program;
                                                                                     initiate the detection
                                                                                     monitoring program; and
                                                                                     begin evaluating the
                                                                                     groundwater monitoring data
                                                                                     for statistically
                                                                                     significant increases over
                                                                                     background levels.
Closure and Post-Closure Care (Sec.   18 months...................................  --Prepare written closure
  257.103--Sec.   257.104).                                                          and post-closure care
                                                                                     plans.
Recordkeeping, Notification, and      6 months....................................  --Conduct required
 Internet Requirements (Sec.                                                         recordkeeping.
 257.105--Sec.   257.107).                                                          --Provide required
                                                                                     notifications.
                                                                                    --Establish CCR website.
----------------------------------------------------------------------------------------------------------------

IX. Implementation of the Minimum Federal Criteria and State Solid 
Waste Management Plans

    As explained earlier in this document, the final regulations EPA is 
promulgating under RCRA subtitle D impose minimum federal criteria with 
which CCR units must comply without any additional action by a state or 
federal regulator. As discussed previously in this document, under the 
provisions of subtitle D applicable to solid waste, states are not 
required to adopt or implement these regulations, to develop a permit 
program, or submit a program covering these units to EPA for approval 
and there is no mechanism for EPA to officially approve or authorize a 
state program to operate ``in lieu of'' the federal regulations.
    EPA has, however, received numerous comments regarding the 
potential implementation challenges that this statutory and resulting 
regulatory structure may pose, particularly in states that already have 
a comprehensive regulatory program governing CCR units. These concerns 
include the fact that facilities may need to comply with two sets of 
potentially differing regulations, perhaps resulting in confusion for 
the regulated community and the general public, and also potentially 
resulting in inconsistent results from citizens seeking enforcement of 
the criteria. The

[[Page 21430]]

commenters were also concerned that there is no explicit mechanism for 
EPA to officially approve a state program (as there is in subtitle C or 
in the municipal solid waste provisions of subtitle D). In addition, in 
states without a current formal program for overseeing CCR landfills 
and surface impoundments at coal fired electric utilities, stakeholders 
have expressed a preference for a state mechanism for implementing the 
federal requirements. Finally, many stakeholders expressed a strong 
preference for a permit program with its opportunities for public input 
and transparency.
    Moreover, EPA recognizes the critical role that our state partners 
play in implementation and ensuring compliance with environmental 
regulations. This is particularly important in complex situations, such 
as presented by CCR landfills and surface impoundments that involve 
corrective action and requirements and timelines for closure of units. 
EPA expects that states will be active partners in overseeing the 
regulation of CCR landfills and CCR surface impoundments, and has 
adopted a number of provisions to ensure that States have the 
information necessary to undertake this role. First, the final 
regulations require owners or operators of regulated CCR units to 
notify the state of actions taken to comply with the requirements of 
the rule (see Sec.  257.106). Facilities will also be required to 
maintain a publicly accessible internet site that will document the 
facility's compliance with the requirements of the rule; states (along 
with other members of the public) will be able to access this site to 
monitor facility activities (see Sec.  257.107). (For a detailed 
discussion of these requirements, please see Unit VI.N of this 
document.)
    In order to ease implementation the regulatory requirements for CCR 
landfills and CCR surface impoundments, EPA strongly encourages the 
states to adopt at least the federal minimum criteria into their 
regulations. EPA recognizes that some states have already adopted 
requirements that go beyond the minimum federal requirements; for 
example, some states currently impose financial assurance requirements 
for CCR units, and require a permit for some or all of these units. 
This rule will not affect these state requirements. The federal 
criteria promulgated today are minimum requirements and do not preclude 
States' from adopting more stringent requirements where they deem to be 
appropriate.
    As noted above, commenters on the proposal voiced concerns that 
because EPA does not have the authority to approve a state program 
under subtitle D of RCRA, there is no document in which EPA formally 
provides its judgment that a state solid waste program substantially 
incorporates the minimum federal criteria. However, a mechanism for 
this has been available for many years through the solid waste 
management planning process already in the regulations at 40 CFR part 
256 ``Guidelines for Development and Implementation of state Solid 
Waste Management Plans.'' This process, designed early in the 
development of the waste management infrastructure, was structured to 
encourage states to effectively plan for and manage their solid wastes, 
including upgrading or closing any units that were considered ``open 
dumps'' through the development of SWMPs. Currently most states have 
SWMPs that have previously been submitted to and approved by EPA. EPA 
strongly recommends that states take advantage of this process by 
revising their SWMPs to address the issuance of the revised federal 
requirements in this final rule, and to submit revisions of these plans 
to EPA for review, using the provisions contained in 40 CFR part 256. 
To be clear, EPA is not suggesting that states revise their entire 
SWMPs, but only that states revise their plans to address the revised 
federal requirements being promulgated today. EPA would then review and 
approve the revised SWMPs provided they demonstrate that the minimum 
federal requirements in this final rule will be met. In this way, EPAs 
approval of a revised SWMP signals EPA's opinion that the state SWMP 
meets the minimum federal criteria.
    As noted above, the part 256 regulations established the system for 
the development and approval of initial SWMPs as well as their 
revisions. For the convenience of the reader, we describe these 
regulations in the following paragraphs. The regulations lay out a 
series of requirements that a plan must meet to be approved, as well as 
a number of recommendations that should also be reflected in the solid 
waste management plan. (e.g., 40 CFR 256.01-256.04 and 256.20-256.27.) 
For example, Sec.  256.02 sets out the scope of the SWMPs, requiring 
that the plans address ``all solid waste in the state that poses 
potential adverse effects on public health or the environment or 
provides an opportunity for resource conservation or resource 
recovery.'' The regulations also specify that the plan must require 
that all solid waste shall be disposed of in ``sanitary landfills,''--
i.e., units that meet any federal requirements promulgated under RCRA 
section 4004(a)--or otherwise disposed of in an environmentally sound 
manner. 40 CFR 256.01(a)(2). The plan must also prohibit the 
establishment of new open dumps, and provide for the closing or 
upgrading of all existing open dumps within the state, pursuant to the 
requirements of RCRA section 4005. 40 CFR 256.01(a)(2)-(3). State plans 
must also ``set forth an orderly and manageable process for achieving 
the objectives of the Act and meeting the requirements of these 
guidelines.'' 40 CFR 256.02(d). The regulations further specify that 
the plan ``shall describe as specifically as possible the activities to 
be undertaken, including detailed schedules and milestones.'' Id.
    The part 256 regulations further require a SWMP to identify the 
state's legal authorities, and regulatory powers, including any 
revisions that may be necessary to implement the plan. 40 CFR 
256.02(e). The plan must also identify and set out the responsibilities 
of state, local, and regional authorities that will implement the state 
plan. 40 CFR 256.10(a). Thus, the SWMP is the comprehensive compendium, 
developed and adopted with public participation, setting forth how 
solid waste is managed in a particular state. As such, SWMPs have been 
a key component of solid waste programs for many years. As stated 
above, states that have approved plans will only need to address these 
requirements for CCR landfills and surface impoundments.
    In addition to the substantive requirements, the part 256 
regulations impose a number of procedural obligations. Before 
submission to EPA, the SWMP must be adopted by the state pursuant to 
state administrative processes and developed in accordance with the 
public participation requirements set out in Sec.  256.60. In addition, 
all SWMPs were to contain procedures for revisions. 40 CFR 256.03(e). 
EPA anticipates that states would rely on their existing procedures to 
revise their SWMPs to implement the new federal criteria.
    Currently, most states have approved SWMPs. These approvals were 
based on the requirements applicable to solid waste management that 
were in force at the time of approval. Now, because EPA is promulgating 
revised federal criteria, the facilities that will be considered to be 
``sanitary landfills'' and ``open dumps'' is changing. Thus, EPA 
expects that SWMPs in many states will need to be revised to account 
for these revised Federal requirements. Consistent with the provisions 
in Sec.  256.01(a)(2)-(3) and with the requirement in Sec.  256.03(e) 
that such plans are to be revised where

[[Page 21431]]

necessary, in order to maintain approval of these plans EPA expects 
that states will revise their SWMPs to account for the promulgation of 
revised federal criteria for CCR landfills and surface impoundments.
    As fully explained later in this section, the plans are generally 
the best tool available for demonstrating how CCR units will be 
regulated in a state, including how the state intends its state 
requirements to relate to the federal regulations. In addition, EPA 
anticipates that the public participation processes will have 
substantial benefit, by involving all sectors of the community in 
addressing the management of CCR in a particular state.
    EPA believes that the revised SWMPs will have significant benefits 
and provide the best mechanism available to respond to the concerns 
expressed by commenters regarding the role of states in management of 
this waste. First, the revised plans will enable states to set out, as 
part of their overall solid waste program, how the State intends to 
regulate CCR landfills and surface impoundments; that is, these plans 
can demonstrate how, if at all, the state program has incorporated the 
minimum national criteria and can highlight those areas where the state 
regulations are more stringent than or otherwise go beyond the federal 
minimum criteria. For example, the plan can describe the actions the 
state will take to oversee CCR units, particularly those units 
undergoing closure or corrective action, and how the State intends to 
review or use the notices and other information pertaining to the units 
that the facility owners will be providing to the state (as required in 
the federal regulations). Providing this detail can greatly assist the 
regulated community to understand the regulatory structure under which 
they will be operating. It can also assist the general public in 
understanding the regulations and thereby their ability to monitor 
industry's compliance with the rule.
    Second, substantial benefits will be gained through the public 
participation process required as part of revising the state plans. See 
40 CFR 256.60. At a minimum, these processes will promote greater 
awareness of the federal regulatory requirements, as well as how these 
fit into the overall context of solid waste management in the State, 
which will be very valuable as the new minimum criteria for CCR are 
implemented. In addition, these processes will provide the public and 
communities near CCR landfills and surface impoundments with an 
opportunity to participate in the decision making about how CCR are 
managed in their state. Finally, the record generated by the public 
participation process has an inherent value to states, the utilities, 
and the general public in that it can demonstrate explicitly the manner 
in which issues related to the regulation of CCR landfills and surface 
impoundments were raised and resolved in the state. This record would 
be a value in any later proceedings seeking enforcement of the rule.
    Third, once EPA has approved a SWMP that incorporates or goes 
beyond the minimum federal requirements, EPA expects that facilities 
will operate in compliance with that plan and the underlying state 
regulations. In those circumstances, EPA's view is that facilities 
adhering to the requirements of a state program that is identical to or 
more stringent than an approved SWMP will meet or exceed the minimum 
federal criteria. In addition, EPA anticipates that a facility that 
operates in accord with an approved SWMP will be able to beneficially 
use that fact in a citizen suit brought to enforce the federal 
criteria; EPA believes a court will accord substantial weight to the 
fact that a facility is operating in accord with an EPA-approved SWMP. 
In addition, as noted above, the record generated by the public 
participation process in developing the SWMP has an inherent value to 
the states, the utilities, and the general public in any such 
litigation. The more specific the record is on the public process 
regarding how the SWMP would incorporate the minimum federal 
requirements and any state oversight the more valuable it would be in 
any court proceedings to complement EPA's approval of the SWMP. As 
fully explained earlier, EPA approval of a state SWMP does not mean 
that the state program operates ``in lieu of'' the federal program as 
EPA does not have the authority to make such a determination.
    The process and criteria for approval of SWMPs are set out in 40 
CFR part 256. The part 256 regulations state that EPA has six months 
from submittal of a plan to either approve or disapprove it. The 
regulations further state that EPA will approve a plan if the agency 
determines that the plan: (a) Meets the requirement set out in RCRA 
Section 4003(a)(1), (2), (3), and (5); (b) and contains provisions for 
revisions. Those requirements of 4003(a) are: The identification of the 
responsibilities of state, local, and regional authorities in the 
implementation of the plan and the means for coordinating regional 
planning and implementation; prohibition on the establishment of new 
open dumps and the requirement that all solid waste be utilized for 
resource recovery or disposed of in landfills meeting the minimum 
federal criteria; provision of the closing or upgrading of all existing 
open dumps; and no prohibition on negotiating or entering into 
contracts for the supply of solid waste to resource recovery 
facilities. In this rule, EPA has established minimum national criteria 
for CCR disposal facilities, which effectively define when CCR disposal 
facilities are open dumps. In order for EPA to approve a revised state 
SWMP, it must determine that the state plan provides enforceable 
regulatory requirements for the closing or upgrading of CCR disposal 
facilities that constitute open dumps. A state SWMP can do so through 
direct incorporation and implementation of the minimum federal criteria 
established by this rule or through incorporation of alternative 
requirements that are at least as protective of public health and the 
environment.
    EPA anticipates that it will be able to review and approve state 
SWMPs that adopt the federal regulations in total or go beyond the 
federal minimum criteria very quickly; EPA's review of plans that do 
not adopt the federal minimum criteria or alter them substantially is 
likely to be more difficult and therefore more time consuming. EPA's 
review of and decision to approve or disapprove a state solid waste 
management plan will be based on the record before the Agency at the 
time of that decision. This record includes the record developed during 
the public participation process in which the state engaged prior to 
submitting the revised SWMP to EPA for approval. Should information 
come to EPA's attention at a later date that a state is not 
implementing its approved plan or taking actions at variance with the 
plan's provisions, EPA will take appropriate steps including 
potentially withdrawing approval of the SWMP.
    Because SWMPs form a critical part of the implementation of this 
rule, EPA intends to engage the states very soon after promulgation of 
the minimum criteria to develop a streamlined, efficient process for 
review and approval of these revised plans. EPA also intends to develop 
both guidance for states to use to submit revisions and for EPA to use 
in its review of the revisions.
    In addition, EPA is exploring options for developing and publishing 
the statutorily required inventory of open dumps. Specifically, within 
one year of the promulgation of federal criteria under RCRA section 
4004(a), section 4005(b) directs EPA ``to assist the states in 
complying'' with the directive in section 4003(a)(3) that state SWMPs

[[Page 21432]]

shall provide for closure and upgrading of open dumps (i.e., facilities 
that do not meet the revised federal criteria) by publishing an 
inventory of all ``open dumps'' in the US. 42 U.S.C. 6945(b). Because 
the minimum criteria promulgated today include implementation 
timelines, it is possible for a facility to become an open dump in the 
future for failure to meet the minimum criteria. Thus, EPA anticipates 
publishing an initial inventory and likely subsequent periodic updates.
    Finally, in addition to benefits just described of a revised SWMP, 
RCRA Section 4005 provides an incentive in certain circumstances for 
states to obtain EPA approval on revised SWMPs. Under section 4005, 
States with approved SWMPs can provide additional time for facilities 
that do not meet the national minimum criteria (i.e., ``open dumps''), 
to come into compliance. As noted above, within one year of the 
promulgation of federal criteria under RCRA section 4004(a), section 
4005(b) directs EPA ``to assist the states in complying'' with the 
directive in section 4003(a)(3) that state SWMPs shall provide for 
closure and upgrading of open dumps (i.e., facilities that do not meet 
the revised Federal criteria) by publishing an inventory of all ``open 
dumps'' in the US. 42 U.S.C. 6945(b). Facilities on this inventory are 
eligible to obtain a ``schedule of compliance'' from a state with an 
approved management plan, provided certain additional criteria have 
been met. Specifically, the facility must demonstrate that it is unable 
to use other ``public or private alternatives'' to manage its waste in 
the non-compliant unit. In such cases, the state may establish a 
schedule of remedial measures that includes ``an enforceable sequence 
of actions or operations'' which must lead to compliance within a 
``reasonable time (not to exceed five years from the date of 
publication of criteria).'' 42 U.S.C. 6945(a). Such a schedule would 
shield the facility from any suit brought to enforce the criteria. 
Thus, if a State receives EPA approval on its revised plan, it can 
offer facilities additional time, albeit limited, to come into 
compliance with the federal requirements. EPA expects, however, that 
few facilities will either be eligible for or need to take advantage of 
this flexibility. First, as a practical matter, only a limited number 
of facilities or units will fall into the category of open dumps within 
the relevant timeframes. As noted, an open dump is defined as a solid 
waste facility that does not meet the federal minimum criteria. 42 
U.S.C. 6903(14). As also explained, the final criteria establish 
timeframes for facilities to implement the technical requirements, 
ranging between six months to several years, including certain 
provisions that authorize extensions. Until those deadlines pass, the 
facility is not an open dump and therefore would not be eligible for or 
need a compliance schedule under section 4005. Because the statute 
limits the states' ability to set compliance schedules to five years 
from the publication of the criteria, if a facility is out of 
compliance with the criteria either shortly before or after this time 
five-year timeframe, from a purely practical perspective, compliance 
schedules are no longer a viable option. Thus for certain of the 
provisions (e.g., closure, which generally must be completed within 
five years) compliance schedules would never be available.
    Second, the timeframes in the regulation reflect EPA's considered 
judgment of the amount of time that would realistically be needed under 
normal circumstances for a facility to come into compliance, based on 
standard engineering practices used throughout the industry. Most 
facilities will, in fact, be able to comply with the federal criteria 
within the specified timeframes, and so will not need to seek a 
compliance schedule. For example, as part of its Dam Safety Assessment 
program, EPA evaluated all CCR surface impoundments with a dam hazard 
potential rating of ``high'' or ``significant,'' using criteria that 
were essentially the same as the technical criteria adopted in the 
final rule. As of the completion of that program, all units were either 
rated satisfactory, or were taking steps to ensure the structural 
stability of the unit. EPA acknowledges that ensuring the structural 
stability of these units requires continued maintenance and oversight, 
so past compliance is no guarantee of future compliance. However, our 
experience from the Assessment Program leads us to expect that the vast 
majority of CCR surface impoundments will be able to demonstrate 
compliance with the structural stability requirements in the final 
criteria within the specified timeframes. Any facility that seeks to 
justify an extension would have a heavy burden to demonstrate that 
anything longer than a minor amount of time is needed to implement the 
structural stability requirements would meet the statutory standard 
(i.e., be ``reasonable''). Similarly, absent factors beyond the 
facility's control (i.e, ``Acts of God'') EPA is unable to envision the 
circumstances that would support a decision that additional time beyond 
the 30 months already provided in the criteria to comply with the 
groundwater monitoring requirements would be ``reasonable.''
    Third, RCRA section 4005(a) imposes a number of requirements that 
will further limit both the circumstances in which a compliance 
schedule may be granted, and the amount of time that states will 
ultimately be authorized to grant. 42 U.S.C. 6945(a). Section 4005(a) 
requires that to obtain a compliance schedule, the facility must first 
demonstrate that it has considered other public or private alternatives 
to comply with the prohibition on open dumping and is unable to utilize 
such alternatives.\127\ At a minimum, this means that the facility must 
demonstrate that there are no alternative units that meet the federal 
requirement, either on-site or off-site, that can be used to dispose of 
the CCR. EPA also interprets this provision to require the facility to 
demonstrate that it has made a good faith effort to comply with the 
criteria, which would include documenting the actions that had been 
taken, along with the facts demonstrating the reasons that compliance 
was not feasible within the criteria's timeframes. As has been 
previously discussed, cost is not a factor that is appropriately 
considered under sections 1008(a)(3), 4004(a), or 4005(a), and so would 
not provide an adequate justification for these purposes either.
---------------------------------------------------------------------------

    \127\ Upon promulgation of criteria under sections 1008(a)(3) 
and 4004(a), the continued use of any unit that does not comply with 
these criteria is prohibited, as ``open dumping,'' unless a 
compliance schedule has been established.
---------------------------------------------------------------------------

    Further, the statute requires that a schedule for compliance 
specify ``a schedule of remedial measures, and an enforceable sequence 
of actions, leading to compliance within a reasonable time.'' Id. This 
means that any compliance schedule must lay out precisely the 
activities that remain to be completed, along with clear and 
enforceable deadlines for each. Again, this will effectively serve to 
limit the ultimate amount of time that would be granted in any 
individual case.
    Finally, as stated earlier, the statute requires that any schedule 
to bring an open dump into compliance is to be limited to a 
``reasonable time,'' that is not to exceed five years from the date of 
publication of the federal criteria. Whether a particular period of 
time is ``reasonable'' depends on the facts of the particular 
situation, but, generally speaking, it should take into account the 
technical complexity of the requirement, the activities that remain

[[Page 21433]]

to be completed, the reasons for the lack of compliance, and other 
particular factors such as geology, geography, weather, and engineering 
circumstances. For example, EPA expects that a significantly lower 
amount of time would be reasonable for a facility that simply chose to 
delay implementation than for a facility whose compliance was 
complicated by factors beyond its control. Overall, to be consistent 
with the statute, EPA expects that facilities seeking to establish an 
alternative compliance schedule would need to provide a factual 
justification that not only documents the reasons that compliance 
within the criteria's timeframes was not feasible, but carefully 
documents the facts that would support a determination that any 
significant extension of time to come into compliance is 
``reasonable.''
    EPA expects that as part of any revised solid waste management 
plans, a state would explain the criteria it intended to use to 
determine whether and how much additional time to comply with the 
federal criteria should be granted. See 40 CFR 256.04(f) and 256.26. 
Consistent with the statute's directives, EPA expects that any 
extension would be limited to the time absolutely necessary to bring a 
unit into compliance, and that five years would not automatically be 
granted. Nor would a revised solid waste management plan that granted 
all ``open dumps'' an additional five years generally meet the 
regulatory criteria for approval. Id. EPA also expects that states 
would consider the original timeframes laid out in the criteria. As 
previously discussed, in developing these time frames EPA sought to 
achieve a balance between the minimum amount of time that would 
realistically be needed to properly and adequately implement the 
technical requirements, and the need to expeditiously address the 
significant risks associated with CCR units. EPA therefore expects that 
in granting additional time under compliance schedules, states will be 
guided by the same considerations. As documented throughout this 
preamble, CCR disposal units do pose significant risks to public health 
and the environment; it is therefore critical that actions to implement 
these criteria be taken expeditiously to address these risks. EPA 
intends to closely review those portions of a state solid waste 
management plan that address the processes and criteria for 
establishing compliance schedules.
    In conclusion, EPA believes that the use of the solid waste 
management plan revision process is the best mechanism available under 
RCRA subtitle D to address the states' interest in obtaining formal EPA 
``approval'' of their solid waste management plans. EPA will continue 
to work with the states as the rules are implemented to ensure that 
this process is streamlined and efficient.

X. Risk Assessment

    EPA revised and updated the 2010 draft risk assessment using 
mathematical models to determine the rate at which chemical 
constituents may be released from different waste management units 
(WMUs), to predict the fate and transport of these constituents through 
the environment, and to estimate the resulting risks to human and 
ecological receptors. Modeling was conducted in a step-wise fashion, 
with more refined analyses used at each subsequent step. Below, EPA 
discusses how the risk assessment was revised and updated in response 
to the various public comments received. The Agency also provides a 
summary of the analyses conducted as part of the risk assessment and 
the final conclusions drawn from these analyses. For further 
discussion, see the revised risk assessment and response to comments 
documents available in the docket.

A. Response to Public Comments

    EPA received numerous, general comments on both the draft risk 
assessment and subsequent NODAs. These comments tended to express 
general support or disapproval for the risk assessment methodology, 
data, or results. However, these comments did not provide any specific 
technical recommendations or data that could be used to improve the 
risk assessment. EPA appreciates the overwhelming interest of the 
public regarding the Agency's risk assessment. However, without any 
substantive critique that could be acted upon, EPA could not alter the 
risk assessment in response to these more general comments. To the 
extent that any commenter mentioned substantive issues regarding a 
specific aspect of the risk assessment, these comments are further 
addressed in subsequent sections of this preamble.
1. Comments Related to Fate and Transport Modeling
    COMMENT: Commenters wondered how realistic results may be using a 
risk assessment model that assumes current conditions will be 
maintained for 10,000 years. Specifically, commenters were concerned 
about the assumption that constituent concentrations in the leachate 
remain constant throughout that timeframe. In addition, commenters 
questioned the assumption that well use and climate conditions will 
remain constant for 10,000 years.
    EPA RESPONSE: EPA acknowledges that the 10,000-year groundwater 
modeling time horizon required further clarification in the revised 
risk assessment. Thus, the text in the revised risk assessment has been 
updated to make it clear that the selection of a maximum 10,000-year 
time horizon does not mean that all model simulations continue for the 
full 10,000 years. Specifically, Section 4 states:
    EPA ran the model until either the observed groundwater 
concentration of a constituent at the receptor point reached a peak and 
then fell below a model-specified minimum concentration (10-16 mg/L), 
or the model had been run for a time period of 10,000 years.
    Although groundwater concentrations are modeled beyond the observed 
peak or maximum average concentrations, these post-peak or post-maximum 
average predictions are not used in estimates of risk. In many cases 
the leachate plume reaches the receptor point much sooner than 10,000 
years. As discussed in Section 5 and appendix K of the revised risk 
assessment, on a national scale, both unlined and clay-lined surface 
impoundments consistently pose peak risks within 100 years. Meanwhile, 
composite liners show much longer peak arrival times, close to 10,000 
years for most surface impoundment runs. Peak arrival times are longer 
for landfills, and more than 10,000 years for composite-lined 
landfills. Under such timeframes, EPA acknowledges that surface 
conditions may change significantly, compounding the uncertainty 
associated with the predicted exposures and risks. However, EPA also 
notes that the time to first exceedance of selected risk criteria is 
typically considerably less than the time to the greatest exceedance.
    EPA acknowledges that future groundwater use patterns may shift as 
the number and location of receptors changes, and that it is unknown 
whether future changes in receptor locations and other surface 
conditions would result in greater, lesser, or the same risk as 
predicted in this analysis. However, no known data exist that would 
allow EPA to do more than speculate about future population dynamics. 
Thus, the Agency relied on the best available data on the current 
population to conduct the revised risk assessment. The approach used to 
place residential groundwater wells is further discussed in Section 4 
and appendix B of the revised risk assessment, and the associated 
uncertainties are discussed in Section 5.

[[Page 21434]]

    COMMENT: Comments related to the specifics of the groundwater 
transport modeling were received from commenters. Issues covered in 
their comments included the following:
    Geochemical Modeling:
     The way that soil and aquifer Kd values were 
determined and used, including the fact that the risk assessment did 
not explicitly model oxidation/reduction reactions and precipitation-
dissolution processes that may influence the chemical fate and 
transport.
     Whether hydrogeologic settings were assigned correctly.
    Selection of Sorbents:
     The selection of iron oxides, and dissolved organic matter 
(DOM) and particulate organic matter (POM) to represent all sorbents in 
soil and aquifer materials.
     The selection of goethite as the iron oxide mineral used 
to estimate sorption to vadose zone and aquifer materials.
     The treatment of POM and DOM in the MINTEQA2 modeling used 
to generate the Kd values (sorption isotherms) used in the 
analysis.
     The adequacy of sensitivity and uncertainty analyses for 
the MINTEQA2 modeling.
    Kd Values:
     The approach used to determine the value of pH in the 
aquifer for selecting Kd.
     The subsequent calculation of the retardation factor.
    Arsenic Speciation:
     The assumption that arsenic III is the only or dominant 
form of arsenic is too conservative, as arsenic III readily converts to 
the less mobile arsenic V species under aerobic conditions.
     A commenter requested time to exceedance results for 
arsenic species and other constituents, as well as distance versus 
concentration output from EPACMTP.
    EPACMTP Assumptions and Simplifications:

--The appropriateness of EPACMTP and its various assumptions and 
simplifications for groundwater modeling, including:
--Not altering the chemistry of the aquifer receiving leachate.
--Not simulating variable oxidation-reduction potential conditions or 
multiple chemical species during a model run.
--Not evaluating the potential mobilization of non-waste related metals 
from soils when exposed to leachate with potentially different 
geochemistry compared to ambient conditions.
--Not considering the potential occupation of adsorption sites by 
naturally occurring metals or competition from multiple contaminants.
--Not considering mounding-induced reduction of the unsaturated zone 
thickness or other cases where the groundwater table is in direct 
contact with the bottom of the WMU.
--Not considering fractured rock, karst, and other complex 
hydrogeologic settings.

    The comments also addressed the general need for more transparency 
in the data and methods used in the analysis and the need for 
validation and/or comparison of model inputs and results to site-
specific field data.
    EPA RESPONSE: The following is EPA's response broken out by 
subtopic.
    Geochemical Modeling:
    EPA recognizes that explicit reactive/geochemical modeling would be 
more realistic than using linear and nonlinear partitioning 
coefficients. EPA considered the use of the Objects Representing 
Chemical Speciation and Transport (ORCHESTRA) model during revisions to 
the risk assessment because it can account for geochemical 
interactions, such as aqueous complexation, precipitation, surface 
complexation, and ion exchange.\128\ However, such modeling is not a 
practical approach for a nationwide analysis because the data 
collection effort necessary to populate such a model on a nationwide, 
location-based level would be prohibitively expensive. Even assuming 
such data were available to populate ORCHESTRA or a similar model, the 
complexity of the algorithms necessary to account for highly variable 
geochemical and hydrogeologic conditions nationwide and the time 
required to run such a model would also be impractical. Furthermore, 
the use of Kd as a surrogate for dilution/sorption/
precipitation processes is a widely used and accepted method in both 
the scientific literature and the groundwater modeling community, 
provided the values of Kd used are appropriate to account 
for the range of potential attenuation processes.\129\ Therefore, for a 
nationwide analysis, the use of Kd is a practical and 
necessary simplification. EPA has added discussion to the risk 
assessment to clarify Kd-related issues raised by the 
commenters. Appendix H of the revised risk assessment displays select 
percentiles of the Kd values used in the analysis. These 
values were derived from the isotherm sampling performed by EPACMTP and 
used in the modeling (including effective Kd values for the 
unsaturated zone). A listing of all individual Kd values 
available in the MINTEQA2 isotherms used in these analyses would not be 
practicable. Instead, the full input and output files are available to 
the public in the docket.
---------------------------------------------------------------------------

    \128\ Meeussen, J.C.L. 2003. ORCHESTRA: An Object-Oriented 
Framework for Implementing Chemical Equilibrium Models. 
Environmental Science & Technology 37(6):1175-1182.
    \129\ U.S. EPA. 1999. Understanding Variation In Partition 
Coefficient, Kd, Values Volume I: The Kd Model, Methods of 
Measurement, and Application of Chemical Reaction Codes. EPA 402-R-
99-004A. OAR. Washington, DC. August.
---------------------------------------------------------------------------

    Some commenters suggested that EPA should focus on the effect of 
redox potential in the groundwater on fate and transport. While this is 
possible, it would take significant effort to set up this type of 
approach for every inorganic constituent considered in the risk 
assessment, and it was determined not to be necessary. EPA did 
indirectly account for some of the major effects of redox potential 
when modeling arsenic and other constituents for which speciation is 
known to have a significant impact on mobility. For these constituents, 
a model run was conducted for each species under the assumption that 
all of the constituent mass was present as that speciation. Therefore, 
EPA did not evaluate redox, and acknowledges this is a source of 
uncertainty for the groundwater transport modeling approach. Commenters 
expressed concern about the assumption of a single speciation, noting 
that it is likely that constituents will be present as some combination 
of the different species. EPA acknowledges that this approach is a 
simplification of real world conditions; however, the Agency believes 
this approach is useful because it provide bounding estimates that can 
inform the risk assessment.
    Regarding the concern that there were possible errors in 
hydrogeological assignments, these assignments have been updated in the 
revised risk assessment based on a more robust and accurate dataset for 
waste management units (WMU) and facility locations. These data are 
discussed in Section 3 and appendix B of the revised risk assessment. 
Because these assignments were based on more complete GIS coverages of 
soils and aquifers across the U.S., they are more consistent and 
reliable than the previous ones in representing the spatial variability 
in hydrogeologic environments needed by the EPACMTP model.
    Selection of Sorbents:
    In recent years, databases of equilibrium sorption reactions have 
been compiled in the literature for several of the dominant potential 
sorbents in the environment, including two common iron oxide minerals: 
hydrous ferrous oxides (HFO) and

[[Page 21435]]

goethite.130 131 Because of the availability of these data 
and their prevalence in the environment, these are the sorbent types 
available for MINTEQ2 modeling used to develop constituent sorption 
isotherms. Other common hydrous oxides that can sorb chemicals include 
hydrous oxides of aluminum, manganese, and silicon (Dzombak and Morel, 
1990); however, there were insufficient data on these to consider their 
use. To determine the most appropriate iron oxide sorbent, EPA chose 
goethite as the most appropriate form of hydrous iron oxide for the 
risk assessment to avoid an underestimation of risk. While both 
goethite and HFO are common forms of iron oxide in soils, goethite is a 
much poorer adsorbent than HFO, thereby leading to relatively greater 
groundwater plume concentrations. EPA acknowledges that HFOs are common 
as well and there is the potential for HFOs with greater sorption 
affinities than goethite to be present at some CCR disposal sites. In 
reaching this conclusion, EPA consulted experts who published on this 
subject (specifically, Dr. David Dzombak, Dr. Samir Mathur and Dr. 
Jerry Allison), developer of MINTEQA2. EPA agrees that this was a 
necessary assumption.
---------------------------------------------------------------------------

    \130\ Dzombak, D.A and F.M.M. Morel. 1990. Wiley-Interscience, 
New York, 393 pp.
    \131\ Mathur, Samir S. 1995. Development of a Database for Ion 
Sorption on Goethite using Surface Complexation Modeling. Carnegie 
Mellon University, M.S. Thesis, Department of Civil and 
Environmental Engineering.
---------------------------------------------------------------------------

    EPA also recognizes that limiting MINTEQA2 to two types of sorptive 
materials (iron oxide and organic matter [DOM and POM]) is a 
simplification given the wide range or soil and aquifer materials that 
actually adsorb metals (e.g., clay and other soil minerals). However, 
given that the extensive sorption databases needed to perform MINTEQA2 
are available for POM, DOM, and goethite, they are the best 
representation of subsurface sorption processes active in soils and 
aquifer materials. This decision and the actual approaches used to 
model DOM, POM, and goethite are described in detail in MINTEQA2 
background documents and the associated Response to Peer Review 
Comments for those documents.
    Finally, with respect to the adequacy of sensitivity and 
uncertainty analyses for MINTEQA2, EPA notes that the 2009 sensitivity 
analysis showed that only results for strongly sorbing constituents 
were sensitive to the Kd values output from MINTEQA2. In 
contrast, the three risk drivers identified in the revised risk 
assessment (arsenic, lithium, and molybdenum) all tend to be weakly 
sorbing, with the exception of arsenic in the pentavalent state. 
Furthermore, to the extent Kd affects the risks, Section 5 
of the revised risk assessment evaluated these effects by examining 
alternate speciation (e.g., trivalent and pentavalent arsenic) as well 
as the effect of waste type and waste pH. For these reasons, EPA finds 
that sufficient sensitivity and uncertainty analyses were conducted.
    Kd Values:
    The approach adopted in the risk assessment to determine the value 
of pH in the aquifer (used to select Kd) and the subsequent 
calculation of the retardation factor assumed that, after entering the 
aquifer, the leachate plume would thoroughly mix with the ambient, 
uncontaminated groundwater. One commenter stated that the mixing zone 
would only be present at the periphery of the groundwater plume. This 
is consistent with the general conceptual model used in this risk 
assessment of uniform subsurface flow with recharge. However, EPACMTP 
requires a constant groundwater pH in each model run to model transport 
with nonlinear sorption isotherms. EPA assumed full mixing as a more 
conservative approach to selecting pH because, for most metals, 
sorption/precipitation tends to increase (i.e., Kd goes up) 
with higher pH, which is characteristic of much CCR leachate (i.e., 
assuming full mixing lowers the groundwater pH and, thus, decreases 
sorption). To characterize the potential effect of this simplifying 
assumption on calculated risk results, EPA conducted an uncertainty 
analysis that is presented in Section 5 of the revised risk assessment.
    EPA considered comparing the modeled Kd values to 
available estimates in the published literature, but did not do so for 
three reasons. First, there are many individual values within each 
Kd isotherm that depend both on constituent concentrations 
and MINTEQA2 master variables, such as pH, organic carbon, and iron 
oxide concentrations. Second, measured values are limited to specific 
sites where conditions that may not be fully documented, and because 
such variables can vary from site to site, it can be very difficult to 
determine exactly how well the collected values represent conditions 
across the country. Third, field and laboratory methods for measuring 
Kd vary greatly and are not easy to compare, adding a 
significant measurement uncertainty to the variability issues mentioned 
above. Therefore, not only would this comparison be complicated to 
perform, it would also be subject to its own numerous uncertainties and 
unknown biases, making it unlikely to provide a basis for definitive 
conclusions about the representativeness of the current approach.
    With respect to comments on the calculation of the retardation 
factor, EPA points commenters to U.S. EPA (2003) \132\ which discusses 
how EPA uses Kd values to model sorption in the subsurface 
environment.
---------------------------------------------------------------------------

    \132\ U.S. EPA (Environmental Protection Agency). 2003. EPA's 
Composite Model for Leachate Migration with Transformation Products 
(EPACMTP). Technical Background Document. EPA 53-R-03-002. Office of 
Solid Waste, Washington, DC.
---------------------------------------------------------------------------

    Arsenic Speciation:
    Commenters also pointed out that literature on arsenic V often 
shows that it is orders of magnitude less soluble than arsenic III, 
which appears inconsistent with the results of the 2010 Draft Risk 
Assessment. The draft assessment found similar exposure concentrations 
for both arsenic species. As a result of a combination of different 
updates to the revised risk assessment, the modeled concentrations of 
arsenic III and V are now generally an order of magnitude different, 
although the specific results vary between pathways. One cause of this 
difference is likely the increased distances to receptors in the 
revised risk assessment. The increased distance would lead to 
additional arsenic V attenuation because this species sorbs more 
readily (i.e., has greater Kd values) than arsenic III. 
Section 5 of the revised risk assessment discusses the uncertainty 
associated with modeling both species of arsenic. For the specific 
concentrations at various distances, EPA directs the commenter to 
review the input and output files available in the docket.
    EPA did not model the time to first exceedance of risk criteria, 
but did conduct a sensitivity analysis for the time to peak groundwater 
concentration. The time to peak results for arsenic species and other 
select constituents are presented in Section 5 of the revised risk 
assessment. The distance to nearest well receptors is also discussed in 
Section 5 of the revised risk assessment. The relation of distance 
versus concentration was not explicitly evaluated on a per simulation 
basis, rather all receptor well locations within one mile from the WMU 
footprint were included in the analysis to provide a conservative risk 
estimate.
    EPACMTP Assumptions and Simplifications:
    Comments on the treatment of dispersivity within EPACMTP 
highlighted the need for greater transparency about the model's

[[Page 21436]]

underlying assumptions and input data sources. The documentation for 
the 2010 Draft Risk Assessment did not include comprehensive tables 
detailing model input parameters, their values or distributional 
characteristics, and the sources of the data used. These values are, in 
many cases, publicly available in the EPACMTP Background and 
Parameters/Data Background documents.133 134 EPA still finds 
it inappropriate to duplicate this large amount of data. Instead, the 
revised risk assessment includes an increase in the number of 
references to these documents, and directs readers to refer to these 
documents for further information. Additionally, the full input and 
output files are available to the public in the docket.
---------------------------------------------------------------------------

    \133\ U.S. EPA. 2003. EPA's Composite Model for Leachate 
Migration with Transformation Products (EPACMTP): Parameters/Data 
Background Document. EPA 530-R-03-003. Office of Solid Waste, 
Washington, DC. April.
    \134\ U.S. EPA. 2003. EPACMTP Technical Background Document. 
Office of Solid Waste, Washington, DC.
---------------------------------------------------------------------------

    With respect to the fundamental questions raised about the 
assumptions and simplifications built into EPACMTP, EPA acknowledges 
some limitations within the model. Some simplifications are necessary 
to complete a large, national scale risk assessment, and the model 
provides the most appropriate available tool to complete this type of 
analysis. As discussed in Section 5 of the revised risk assessment, 
EPACMTP has been thoroughly peer reviewed and tested for application in 
large-scale risk assessments. This section also provides additional 
documentation on these internal and external reviews of the model, its 
limitations, and the associated uncertainties. With respect to 
particular criticisms levied:
     EPA alters the chemistry of the aquifer receiving leachate 
by changing the aquifer pH in response to full mixing. Alternatively, 
EPA conducts an analysis in Section 5 using the alternate assumption of 
partial mixing;
     EPA evaluates alternative species in separate model runs. 
As described in the revised risk assessment, EPA believes that 
presentation of these two results bound the range of possible risks 
from a constituent. To the extent that EPA does not model oxidation-
reduction potential, EPA notes that this would require geochemical 
modeling, which was not feasible for the reasons discussed above;
     Full mixing of the leachate plume did not demonstrate 
significant potential to affect aquifer pH. Thus, since pH is one of 
the most significant factors affecting constituent mobilization EPA 
does not believe significant constituent mass from the underlying soils 
will be mobilized in most cases. Instead, it is a site-specific 
consideration that is not possible to include in a nationwide risk 
assessment.
     A discussion of sorbent competition as a limitation of the 
analysis is discussed in Attachment H-1 of appendix H in the revised 
risk assessment.
     EPA did not consider groundwater mounding, groundwater in 
contact with the waste management unit, fractured rock, karst, and 
other complex hydrogeologic settings as these are site-specific 
considerations that could not be accommodated in a nationwide risk 
assessment.
    COMMENT: Several commenters discuss the use of site-specific 
analysis to increase confidence in the risk assessment results. They 
expressed concern that the results are difficult to evaluate given the 
significant variability and uncertainty associated with the national 
scope of the analysis, and that validation or calibration of EPACMTP 
results with actual data is needed, including the potential use of 
damage cases.
    EPA RESPONSE: Commenters expressed concern about validation of the 
EPACMTP model with actual field data and some commenters suggested that 
EPA should use actual monitoring data rather than modeling to assess 
potential risks. EPA recognizes the importance of monitoring data in 
characterizing specific sites. EPA agrees with the commenters that 
confidence in the results of an environmental fate and transport model 
increase significantly when model predictions can be compared favorably 
with measured field results. However, site-specific modeling involves 
extensive data collection and detailed modeling (representing site-
specific conditions and processes), which was not possible for this 
large, national-scale risk assessment. Available site-specific data are 
limited to a relatively small fraction of locations and settings. This 
risk assessment was intended to represent a broad range of potential 
conditions. Consequently, EPA validated the model results with actual 
field data by comparing the results of the national probabilistic, 
Monte Carlo analysis to proven/potential damage cases from across the 
United States. These damage cases represent real-world instances of 
contamination from CCR WMUs that provide the best available comparison 
for the results of the risk assessment. This comparison is presented in 
Section 5 of the revised risk assessment. EPA also provided extensive 
EPACMTP validation results relative to theoretical models and field 
data in appendix D of the EPACMTP technical background document (U.S. 
EPA, 2003a,b).\135\
---------------------------------------------------------------------------

    \135\ U.S. EPA (Environmental Protection Agency). 2003a. EPA's 
Composite Model for Leachate Migration with Transformation Products 
(EPACMTP). Technical Background Document. EPA 53-R-03-002. Office of 
Solid Waste, Washington, DC.
---------------------------------------------------------------------------

    COMMENT: Comments relating to the number of wells contaminated, the 
realistic risk of exposure, well placement within the plume, distance 
to receptor wells, identification of surface water receptors, surface 
water interception modeling, the appropriateness of receiving water 
reaches (e.g. the nearest surface water body), and other receptor or 
well-related issues were received from public commenters.
    Surface Water Interception Modeling:
    Regarding surface water interception, many comments were supportive 
of EPA's approach for simulating the interception of groundwater by 
surface water bodies, which has been added to the revised risk 
assessment. However, some commenters indicated that a meaningful 
allocation of the groundwater plume between a surface water body and a 
downgradient well receptor can only be determined reliably with 
assessment of the system at a local scale.
    Commenters also raised questions regarding the specific surface 
water interception methodology, including the base data and algorithms 
used to calculate stream base flow, net groundwater flow, and the 
contaminant mass loss to groundwater. Concern was expressed about the 
large range of possible values used for Monte Carlo sampling without 
calibrating models to site specific conditions and the potential to 
mismatch parameters. Additionally, concerns were raised that the 
assessment assumed transport directly to the nearest water body without 
reflecting complexities that are often present and could lead to longer 
transport pathways or to pathways to water bodies other than the 
nearest.
    Commenters noted that the vicinity of many WMUs is serviced by a 
municipal water supply, and; therefore, there would be no drinking 
water receptors associated with these WMUs. Comments were also received 
that the one mile distance considered by the transport model is not 
sufficient, because actual receptor wells in many cases are further 
than one mile from facilities. Comments also highlighted the 
possibility that modeled receptor well concentrations may incorrectly 
represent actual

[[Page 21437]]

exposures by sampling from a single aquifer depth. Comments on 
dispersivity noted the need for greater transparency in the report.
    Placement of Receptor Wells, EPACMTP Well Inputs and Assumptions:
    Comments related to the risk assessment's use of water well 
distances from MSWLFs and the Agency's belief that these distances 
would be protective for CCR WMUs. Additional comments focused on the 
assumption that the wells used in this assessment are contaminated 
(i.e., located within the plume), even if the well location used 
reflects a deeper well that may be screened in an uncontaminated 
aquifer; the manner in which the assessment handles uncontaminated 
wells, plume characteristics, groundwater-surface water interactions, 
vertical contaminant concentration across a screened interval in an 
aquifer; and the values used for plume dispersivity.
    EPA RESPONSE: The following is EPA's response broken out by 
subtopic.
    Surface Water Interception Modeling:
    In cases where receptor wells are located downgradient from a 
surface water body that intersects the groundwater table, some or all 
of the groundwater, along with the mass of constituents contained 
therein, is intercepted by the water body before it can reach the well. 
This interception was not modelled in the 2010 Draft Risk Assessment. 
However, a review of the input database for the 2010 Draft Risk 
Assessment found that such a water body was present in approximately 
two-thirds of the Monte Carlo runs. Furthermore, ignoring the loss of 
constituent mass had the effect of overestimating exposures. Thus, in 
the revised risk assessment an EPACMTP model post-processor was created 
to account for surface water interception by removing constituent mass 
flowing into the water body from the groundwater plume, and leaving 
only the remaining groundwater available to migrate to a drinking water 
receptor. The approach used to account for interception is discussed in 
further detail in Section 4 and appendix J of the revised risk 
assessment.
    While commenters were generally supportive of the proposed 
approach, some indicated that a meaningful allocation of constituent 
mass from groundwater into a surface water body required site-specific 
data. Concerns were raised about the assumption that transport occurred 
directly to the nearest water body without reflecting complexities that 
are often present and could lead to longer transport pathways or to 
pathways to water bodies other than the nearest. EPA acknowledges that 
local conditions can make groundwater flow conditions complex, and 
detailed, local-scale assessments would be required to describe these 
conditions accurately. While EPA agrees that local-scale conditions 
must be considered for precise estimation for specific systems, it was 
impractical for EPA to characterize, simulate, and calibrate models for 
the numerous locations across the nation. Discussion of the 
uncertainties associated with this approach has been added to Section 5 
of the revised risk assessment.
    Several questions about the surface water interception methodology 
were raised by the public. The qBaseflow input parameter was derived 
from the NHDplus mean recharge parameter (MEAN_RCHRG) \136\ and the 
size of the water body catchment and reach (see appendix B of the 
revised risk assessment). The approach assumes that all streams 
intersect the shallow aquifer and that all streams either gain water 
from the aquifer or do not interact with the aquifer at all (for 
simplicity and conservatism). As the commenter indicates, qNetflow is a 
key result calculated by subtracting the stream baseflow from the 
average groundwater flow upgradient of the stream. The qNetflow value 
becomes the adjusted groundwater flow beyond the stream, reflecting 
groundwater losses to the stream. One commenter raised a specific 
question about how the methodology handles cases where qNetflow is less 
than zero, but greater than the average groundwater flow. This case 
does not occur with the methodology adopted by EPA, because qNetflow is 
always equal to or less than the average groundwater flow (i.e. streams 
are assumed not to be losing). If qNetflow is negative (i.e., a losing 
stream), all of the groundwater is assumed to migrate to any wells on 
the opposite side of the stream.
---------------------------------------------------------------------------

    \136\ Available online at: water.usgs.gov/GIS/metadata/usgswrd/XML/nhd_recharge.xml.
---------------------------------------------------------------------------

    Model Validation/Calibration:
    Concern was expressed about the large range of possible values used 
in the probabilistic analysis for certain parameters and the potential 
for this to result in a mismatch of input parameters without proper 
site-specific calibration. EPA notes that the revised risk assessment 
is not intended to capture the exact risks at each disposal site. 
Instead, the revised assessment combines the best resolution of site-
based, regional and national data available to provide an estimate of 
potential risks that may occur from current disposal practices. While 
the assigned data for any given model iteration may not reflect the 
exact conditions at a real-world site, the resulting sum of all model 
iterations reflect the range of potential conditions near each WMU, 
weighted by prevalence, across the conterminous United States.
    Placement of Receptor Wells, EPACMTP Well Inputs and Assumptions:
    Comments regarding placement of receptor wells in the probabilistic 
analysis (also known as the appropriateness of receiving water reaches) 
are the result of a fundamental misinterpretation regarding the 
constraints placed on groundwater receptor location to be, as described 
in the 2010 Draft Risk Assessment, ``within the contaminant plume.'' 
This constraint is more fully explained in Section 4.4.3.6 of the 
EPACMTP technical background document.\137\ A citation referring 
readers to that document has been placed in Section 4 of the revised 
risk assessment. Because the comment resulted from a misunderstanding, 
EPA does not believe the sensitivity analysis suggested by the 
commenter is necessary.
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    \137\ U.S. EPA (Environmental Protection Agency). 2003a. EPA's 
Composite Model for Leachate Migration with Transformation Products 
(EPACMTP). Technical Background Document. EPA 53-R-03-002. Office of 
Solid Waste, Washington, DC.
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    Some commenters were concerned that many residents in the vicinity 
of some WMUs may be serviced by a municipal water supply. Because these 
residents would not be exposed to groundwater, the risk assessment 
could overestimate exposures. EPA acknowledges that there may be a 
large percentage of the population that does not rely on groundwater as 
a source of potable water; however, the aim of the risk assessment is 
to estimate the magnitude of potential risk to the exposed population. 
Thus, this does not represent a significant source of uncertainty in 
the risk assessment.
    Comments were also received that the one-mile distance considered 
by the transport model is not sufficient, because actual receptor wells 
in many cases are further distant than one mile from facilities. EPA 
conducted a sensitivity analysis, discussed in Section 5 of the revised 
risk assessment, which indicates that risks beyond the one-mile 
distance are appreciably lower than risks within one mile. Given that 
the highly exposed population was adequately captured by a one-mile 
radius, the significant additional effort required to extend the 
analysis further downgradient was unjustified.

[[Page 21438]]

    With respect to comments related to the placement of wells within 
deeper aquifers, EPA has a policy of addressing uncertainty by erring 
in favor of the protection of human health and environmental quality. 
Consistent with this practice, wells screened within vulnerable, 
surficial aquifers (i.e., the top 10 meters of the saturated zone) 
continue to be the primary focus of the Agency's national-scale 
modeling efforts. Comments also highlighted the possibility that 
modeled receptor well concentrations may incorrectly represent actual 
exposures by sampling from a single aquifer depth. Wells are typically 
screened across an extended depth, and may capture both contaminated 
and pristine groundwater. Due to the constraints of EPACMTP, EPA 
maintained the current approach of modeling exposures at a single 
depth. A discussion of the uncertainties associated with this approach 
has been added to Section 5 of the revised risk assessment.
    In response to comments on the use of MSW landfill data to predict 
the distance to private wells, EPA did not use the MSW data in the 
revised risk assessment. Instead, EPA used synthetic population 
representations of U.S. Census data to place each household and its 
occupants at discrete points across the landscape surrounding CCR WMUs. 
Synthetic populations are realistic representations of households and 
individual residents and their attributes in a given census area, and 
are based on methods that identify realistic locations within each 
block by using LandScan 90-meter night-time population distributions to 
place each household across the landscape.\138\ From these households, 
a distribution of the distances to the nearest well was created. This 
approach is discussed in more detail in appendix B of the revised risk 
assessment. Some commenters suggested that EPA develop site-specific 
estimates of actual populations around facilities rather than relying 
on synthetic populations to determine potential receptor locations. The 
synthetic approach provides the maximum spatial resolution possible for 
publically available population data from the U.S. Census. More site-
specific estimates would be costly, but not necessarily more accurate.
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    \138\ Bhaduri, B., E. Bright, P. Coleman, and M. Urban. 2007. 
LandScan USA: A high resolution geospatial and temporal modeling 
approach for population distribution and dynamics. GeoJournal 
69:103-117.
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    Some commenters were also concerned that the assessment did not 
consider direct discharges from surface impoundments to surface water. 
This pathway was outside the scope of the assessment, because it is 
regulated by the NPDES program. However, this pathway was evaluated in 
Environmental Assessment for the Proposed Effluent Limitation 
Guidelines and Standards for the Steam Electric Power Generating Point 
Source Category,\139\ which will be revised in support of final 
effluent limitation guidelines due to be released in September of 2015.
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    \139\ U.S. EPA. 2013. Environmental Assessment for the Proposed 
Effluent Limitation Guidelines and Standards for the Steam Electric 
Power Generating Point Source Category. EPA-821-R-13-003. Office of 
Water. Washington, DC. 20460. April.
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2. Comments Related to Source Modeling
    COMMENT: The majority of the public commentary in this subcategory 
was dominated by the assertion that Toxicity Characteristic Leaching 
Procedure (TCLP), Synthetic Precipitation Leaching Procedure (SPLP) and 
other laboratory leachate test data are not applicable to CCR wastes. 
Comments specifically regarding the use of Leaching Environmental 
Assessment Framework (LEAF) data for modeling leaching behavior noted 
that the data should be applied appropriately and pointed out the 
following: (1) That the range of conditions (i.e., range of pH) 
encompassed by the LEAF data is broader than those conditions found in 
the field for CCR disposal; (2) high pH limits the mobility of leaching 
constituents; (3) the need for validating LEAF leachate concentrations 
against field data if available; and (4) the reliability of the LEAF 
data is questionable as a result of inconsistencies identified in the 
LeachXS LiteTM database.
    EPA RESPONSE: Only pore water and impoundment water data were used 
to characterize surface impoundments. Therefore, the comments received 
on the use of laboratory leachate data are not relevant for the surface 
impoundment scenario. For landfills, EPA agrees that TCLP, SPLP and 
other single pH test methods may not be the most appropriate leachate 
extraction methods for all waste streams and all disposal scenarios. 
The 2010 Draft Risk Assessment relied on a hierarchy of dissolved 
concentration data to characterize leaching from landfills, ranging in 
order of preference from field leachate data to TCLP. However, new data 
collected using the LEAF test methods have been made available through 
a series of