[Federal Register Volume 82, Number 12 (Thursday, January 19, 2017)]
[Proposed Rules]
[Pages 7400-7430]
[FR Doc No: 2017-00573]

Vol. 82

Thursday,

No. 12

January 19, 2017

Part XIII

 Environmental Protection Agency

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40 CFR Part 192

 Health and Environmental Protection Standards for Uranium and Thorium
Mill Tailings; Proposed Rule

Federal Register / Vol. 82 , No. 12 / Thursday, January 19, 2017 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 192

[EPA-HQ-OAR-2012-0788; FRL-9958-12-OAR]
RIN 2060-AP43

Health and Environmental Protection Standards for Uranium and
Thorium Mill Tailings

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing
new health and environmental protection standards under the Uranium
Mill Tailings Radiation Control Act (UMTRCA) of 1978. The standards
proposed in this action would be applicable to byproduct materials
produced by uranium in-situ recovery (ISR) and would be implemented by
the U.S. Nuclear Regulatory Commission (NRC) and NRC Agreement States.
The EPA initially proposed new health and environmental protection
standards for ISR facilities on January 26, 2015; however, the EPA has
decided to re-propose the rule and seek additional public to comment on
changes to the original proposal, including changes in the regulatory
framework and approach, based on public comment and new information
received from stakeholders.
    The first standards for uranium recovery were issued by the EPA in
1983 when conventional mining and milling were the predominant methods
of uranium extraction, and were last amended in 1995. Since the early
1990s, ISR has mostly replaced conventional milling. This proposed rule
would strengthen the existing regulations for uranium recovery by
adopting new standards addressing groundwater hazards specific to ISR
facilities. As with the original proposal, the primary focus of this
proposal is groundwater protection, restoration and long-term
stability.
    The most significant changes from the original proposal include:
Removing the default 30-year long-term monitoring provision and
shifting to a Resource Conservation and Recovery Act (RCRA) Subtitle C
corrective action framework as a model rather than a RCRA Subtitle C
landfill framework; adding specific criteria and procedures for
approving termination of long-term stability monitoring; deleting gross
alpha particle activity from proposed Table 1 to subpart F of 40 CFR
part 192, and allowing more flexibility for the NRC or Agreement States
to determine on a site-specific basis the constituents for which
concentration based standards are set. The EPA has also sought to
clarify how these standards under UMTRCA complement, and do not overlap
with, the requirements of the Safe Drinking Water Act (SDWA).
    This action also proposes amendments to certain provisions of the
existing rule to address a ruling of the Tenth Circuit Court of
Appeals, to update a cross-reference to another environmental standard
and to correct certain technical and typographical errors. The proposed
rule has been informed by input from the NRC, the U.S. Department of
Energy (DOE), states, tribes, industry, environmental groups and other
stakeholders, and would promote public health and protect groundwater
by reducing the potential for groundwater contamination after
production has ceased, and in aquifers adjacent to ISR facilities
during uranium recovery.

DATES: Comments must be received on or before July 18, 2017.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2012-0788, by one of the following methods:
     www.regulations.gov: Follow the on-line instructions for
submitting comments.
     Email<EMAIL_ADDRESS>     Fax:<PHONE_NUMBER>.
     Mail: Air and Radiation Docket, Environmental Protection
Agency, Mailcode: 2822T, 1200 Pennsylvania Ave. NW., Washington, DC
20460.
     Hand Delivery: EPA West Building, Room 3334, 1301
Constitution Ave. NW., Washington, DC 20004. Such deliveries are only
accepted during the Docket's normal hours of operation; special
arrangements should be made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2012-0788. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be
Confidential Business Information (CBI) or other information whose
disclosure is restricted by statute. Do not submit information that you
consider to be CBI or otherwise protected through www.regulations.gov
or email. The www.regulations.gov Web site is an ``anonymous access''
system, which means the EPA will not know your identity or contact
information unless you provide it in the body of your comment. If you
send an email comment directly to the EPA without going through
www.regulations.gov, your email address will be automatically captured
and included as part of the comment that is placed in the public docket
and made available on the Internet. If you submit an electronic
comment, the EPA recommends that you include your name and other
contact information in the body of your comment and with any disk or
CD-ROM you submit. If the EPA cannot read your comment due to technical
difficulties and cannot contact you for clarification, the EPA may not
be able to consider your comment. Electronic files should avoid the use
of special characters, any form of encryption, and be free of any
defects or viruses. For additional information about the EPA's public
docket visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket: All documents in the docket are listed in the
www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in www.regulations.gov or in hard copy at the Office of Air and
Radiation Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave.
NW., Washington, DC. 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<PHONE_NUMBER>, and the
telephone number for the Air and Radiation Docket is<PHONE_NUMBER>.

FOR FURTHER INFORMATION CONTACT: Ingrid Rosencrantz, Office of
Radiation and Indoor Air, Radiation Protection Division, Mailcode
6608T, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave.
NW., Washington, DC 20460; telephone number:<PHONE_NUMBER>; fax
number:<PHONE_NUMBER>; email address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

A. Does this action apply to me?

    The regulated categories and entities potentially affected by the
proposed standards include:

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                 Category                  NAICS code \1\              Examples of regulated entities
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Industry:
    Uranium Ores Mining and/or                     212291  Facilities that extract or concentrate uranium from
     Beneficiating.                                         any ore processed primarily for its source material
                                                            content.
Leaching of Uranium, Radium or Vanadium            212291  Facilities that extract or concentrate uranium from
 Ores.                                                      any ore processed primarily for its source material
                                                            content.
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\1\ North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by this
proposed action.

B. What should I consider as I prepare my comments to EPA?

    Submitting CBI. Do not submit CBI information to the EPA through
www.regulations.gov or email. Clearly mark the part or all of the
information that you claim to be CBI. For CBI information contained on
a disk or CD ROM that you mail to the EPA, mark the outside of the disk
or CD ROM as CBI and then identify electronically within the disk or CD
ROM the specific information that is claimed as CBI. In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information marked as CBI will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2.
    Tips for preparing your comments. When submitting comments,
remember to:
     Identify the rulemaking by docket number and other
identifying information (subject heading, Federal Register date and
page number).
     Follow directions--The agency may ask you to respond to
specific questions or organize comments by referencing a Code of
Federal Regulations (CFR) part or section number.
     Explain why you agree or disagree, suggest alternatives,
and substitute language for your requested changes.
     Describe any assumptions and provide any technical
information and/or data that you used.
     If you estimate potential costs or burdens, explain how
you arrived at your estimate in sufficient detail to allow for it to be
reproduced.
     Provide specific examples to illustrate your concerns, and
suggest alternatives.
     Explain your views as clearly as possible, avoiding the
use of profanity or personal threats.
     Submit your comments by the comment period deadline.

C. When would a public hearing occur?

    If anyone contacts the EPA requesting to speak at a public hearing
concerning this proposed rule by February 21, 2017, the EPA will hold a
public hearing. If you are interested in attending a public hearing,
contact Mr. Anthony Nesky at<PHONE_NUMBER>. If a public hearing is
held, the Agency will announce the date, time and venue on the EPA Web
site at http://www.epa.gov/radiation/tenorm/40CFR192.html.

D. What documents are referenced in today's proposal?

    The EPA refers to a number of documents that provide supporting
information for the Agency's proposed uranium and thorium mill tailings
standards. All documents relied upon by the EPA in regulatory decision
making may be found in the EPA docket (EPA-HQ-OAR-2012-0788) accessible
via http://www.regulations.gov/. Other documents (e.g., statutes,
regulations, and proposed rules) are readily available from public
sources. The EPA documents listed below are referenced most frequently
in today's proposal.
    EPA 402/D-14-001, ``Considerations Related to Post Closure
Monitoring of Uranium In-Situ Leach/In-Situ Recovery (ISL/ISR) Sites,''
EPA, 2014.
    EPA 402/R-14-003, ``Economic Analysis: Proposed Revisions to the
Health and Environmental Protection Standards for Uranium and Thorium
Mill Tailings Rule (40 CFR part 192),'' EPA, 2016.
    EPA 530/R-09-007, ``Statistical Analysis of Groundwater Monitoring
Data at RCRA Facilities--Unified Guidance,'' EPA, 2009.

E. Preamble Abbreviations

    The following abbreviations are used in this preamble:

ACL Alternate concentration limit
AEA Atomic Energy Act
BID Background information document
CFR Code of Federal Regulations
COOs Civilian owners and operators
DOE Department of Energy
EPA U.S. Environmental Protection Agency
FR Federal Register
ISR In-situ recovery, also known as in-situ leaching (ISL)
MCL Maximum contaminant level
NRC U.S. Nuclear Regulatory Commission
NUREG U.S. Nuclear Regulatory Commission Guides
OMB Office of Management and Budget
RAC Radiation Advisory Committee
RCRA Resource Conservation and Recovery Act
RFA Regulatory Flexibility Act
SAB Science Advisory Board
SDWA Safe Drinking Water Act
UCL Upper control limit
UIC Underground injection control
U.S. United States
UMRA Unfunded Mandates Reform Act of 1995
UMTRCA Uranium Mill Tailings Radiation Control Act of 1978
U.S.C. United States Code
USDW Underground source of drinking water

F. Organization of This Document

    The information presented in this preamble is organized as follows:

I. Executive Summary
    A. Background
    B. Purpose of the Regulatory Action
    C. Summary of the Major Provisions
    D. Summary of the Costs and Benefits
    E. Statutory Authority for This Action
II. Summary of the Proposed Rule
    A. Proposed Standards for Uranium ISR Operations
    B. Amendments to 40 CFR Part 192, Subparts C and D
III. Summary of Changes Made to the Original Proposal and Rationale
for Those Changes
    A. Incorporation of the Initial and Long-Term Stability
Standards in Proposed 40 CFR 192.52
    B. Groundwater Protection Standards
    C. Preoperational Monitoring Requirements
    D. Exempted Aquifers
    E. Excursions
    F. Initial and Long-Term Stability
    G. Corrective Action Program
    H. Costs and Economic Impacts
    I. Other Miscellaneous Changes
IV. Responses to Other Significant Comments That Did Not Result in
Changes to the Original Proposal
    A. Authority To Set and Enforce Standards
    B. Need for New Standards for Uranium ISR Facilities
    C. Applicability
    D. The 95 Percent Confidence Level
V. Summary of Environmental, Cost and Economic Impacts
    A. Environmental Impacts of the Proposed Rule on Groundwater
Quality
    B. Incremental Costs of Complying With the Proposed Rule
    C. Economic Impacts of the Proposed Rule on the Market for
Uranium and the Uranium Industry

    D. Benefits of the Proposed Rule
VI. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution or Use
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations

I. Executive Summary

A. Background

    ISR is a method by which uranium is leached from underground ore
bodies by the introduction of a solvent solution, called a lixiviant,
through injection wells drilled into the ore zone. The process does not
require excavation to extract the ore body from the ground or
conventional milling to extract the uranium from the mined ore. After
the lixiviant is injected underground, it passes through the ore zone
and mobilizes the uranium. The uranium-bearing solution is then pumped
to the surface via extraction wells, and the solution is processed to
extract the uranium. During uranium production, the fluids injected to
mobilize uranium change the chemistry of the aquifer from its original
state, thereby mobilizing uranium and many other minerals and metals.
Groundwater from the ISR production zone can migrate from the
production zone and contaminate nearby groundwater with arsenic,
barium, cadmium, chromium, lead, mercury, selenium, silver, nitrate,
molybdenum, radium and uranium and other constituents. The standards
proposed in this action would minimize the risk of undetected
groundwater degradation and constituent migration during and after ISR
operations have ceased.
    The EPA initially proposed new health and environmental protection
standards for ISR facilities on January 26, 2015 (hereinafter
``original proposal''), with the intention of finalizing the new
standards in 2016.\1\ During the public comment period, the Agency
received over 5,380 public comment letters from a wide range of
stakeholders, with comments covering more than 80 different topics. In
addition, during interagency review, more than 15 groups of
stakeholders met with Office of Management and Budget (OMB) to voice
comments on the original proposal. Commenters were particularly
concerned about the default 30-year long-term monitoring requirement,
felt that the optional method by which a licensee could request
permission to cease long-term stability monitoring lacked sufficient
specificity and believed the number of constituents required to be
monitored was unreasonably burdensome. Several commenters thought the
economic analysis underestimated the compliance costs and identified
several additional categories of costs related to the long-term
monitoring requirements they felt had been omitted from the analysis or
were not representative of the actual costs incurred. Other commenters
felt that several additional types of benefits should be included in
the benefits analysis. After consulting with the NRC and other agencies
and collecting additional information from industry, including
participation in stakeholder meetings during interagency review with
OMB, the EPA decided to make several changes to the original proposal
and solicit additional public comment rather than finalize the rule
with the changes. These changes are described in detail in section III
of this preamble. The most significant changes include removing the
default 30-year long-term monitoring provision and shifting to more of
a RCRA Subtitle C corrective action framework as a model rather than a
RCRA Subtitle C landfill framework, adding specific criteria and
procedures for approving termination of long-term stability monitoring,
deleting gross alpha particle activity from proposed Table 1 to subpart
F, and allowing more flexibility for the NRC and Agreement States
(hereinafter ``regulatory agency'') to determine on a site-specific
basis the constituents for which concentration-based standards are set.
The EPA has also sought to clarify how these standards under UMTRCA
complement, and do not overlap with, the requirements of the SDWA. In
addition to these more significant changes, the EPA has also made minor
changes to the original proposal, such as moving the initial and long-
term monitoring standards to the proposed Sec.  192.52 and moving the
requirements for alternate concentration limits (ACLs) to a separate
section (see proposed Sec.  192.54). In addition to making changes to
the rule text, the EPA also re-calculated the incremental compliance
costs to incorporate estimated non-monitoring costs (e.g., licensing,
leasing fees, continued surety, maintenance) and incorporated
additional cost information provided by industry. The EPA re-evaluated
the economic and energy impacts to both address the concerns raised by
commenters and to incorporate the changes the Agency made to the
standards since the original proposal was published. The revised costs
and economic analysis for this proposal are discussed in section V of
this preamble. While the majority of the changes to the original
proposal are relatively minor, the EPA decided it was appropriate to
re-propose the rule due to the high level of public interest in this
rulemaking. This action provides the public an opportunity to review
and provide comment on the changes made to the original proposal and
allows the EPA to consider and make any additional changes based on
those comments before finalizing the rule. The EPA is requesting
comment on all aspects of this proposed action. Because this is a re-
proposal, and the EPA wishes to consider comments in context, please
re-submit any relevant comments that may have been submitted on the
original proposal.
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    \1\ See 80 FR 4156, January 26, 2015.
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    Several commenters also voiced concerns about information and data
collection, including review of Agreement State regulatory programs
that address ISRs. Although the EPA requested and collected data and
information as outlined in section IV.B of this preamble, the Agency
understands stakeholders concerns and are inviting stakeholders to
submit additional data and analyses to further clarify the ISR process,
including any additional monitoring results and analyses. The EPA will
be collecting additional information on state regulatory programs, as
recommended by several states.

B. Purpose of the Regulatory Action

    The EPA is proposing to add new health and environmental protection
standards to regulations promulgated under UMTRCA. The proposed
standards would regulate byproduct materials produced by ISR, including
both surface and groundwater standards, with a primary focus on
groundwater protection, restoration and stability. By explicitly
addressing the most significant environmental and public health hazards
presented by ISR activities, these proposed standards would address the
shift toward ISR as the dominant form of uranium recovery that has
occurred since the standards for

uranium and thorium mill tailings were promulgated in 1983.
    This rule would provide the necessary framework for consistent and
sustainable protection of groundwater at ISR sites that will continue
to have beneficial uses even if the aquifer has been exempted from
protection under the SDWA.
    Groundwater is a scarce resource that is under increasing pressure,
particularly in the arid West where groundwater has multiple uses,
including for livestock production, crop irrigation, wildlife support,
and human consumption. As groundwater resources are depleted, it
becomes even more important to preserve those resources for future
uses. Stakeholders in these areas are already finding a need to use
groundwater that is of lower quality than desired.\2\ Groundwater that
contains mineral resources, such as uranium, is not necessarily of such
poor quality that it cannot be used for these purposes. By altering the
chemical composition of groundwater, ISR creates reasons to be
concerned about impacts to groundwater, which may be used for human
drinking water, as well as for other purposes, such as livestock
watering, crop irrigation and wildlife support.
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    \2\ Application for Amendment of USNRC Source Materials License
SUA-1601, Ross ISR Project, Kendrick Expansion Area, Crook County,
Wyoming Docket #40-9091, 2015. pp. 3-100; USGS National Brackish
Groundwater Information Sheet 2013; Advanced Treatment for
Groundwater, Treating Low Quality Groundwater for Municipal Use,
Water Engineering and Management, Nov. 2001.
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    While an aquifer or portions of an aquifer may have been exempted
from the protections of the SDWA, the aquifer may be needed in the
future for human drinking water or other purposes. The standards
proposed in this action do not require licensees to improve groundwater
quality, only to provide confidence that: (1) In the area mined, the
applicable constituent concentration standards (set at either
background or health-based levels, whichever is higher), are met and
remain stable; and (2) that uranium recovery operations will not
endanger adjacent aquifers. EPA requests comment on whether
groundwater, once it meets the constituent concentration standards,
could or would potentially be used for drinking water or other
purposes.
    UMTRCA directs the EPA to establish standards of general
application, while the NRC is vested with implementing the EPA's
standards under its licensing and enforcement authority. The EPA has
previously promulgated general standards under UMTRCA for surface
disposal of mill tailings from conventional uranium mining and milling,
but ISR has become the dominant form of uranium extraction since the
1990s. In 2006, an NRC commissioner observed that ISR-specific rules
were needed to provide a national approach to bring predictability to
the industry and state regulators. This view was not predicated on
specific documented instances of groundwater contamination outside of
the ISR production zone. The scope and level of protection of the SDWA
differs from the UMTRCA. The purpose of the SDWA UIC program is to
prevent endangerment of underground sources of drinking water. In
determining whether an aquifer may be exempted from the protection of
the SDWA, the EPA does not consider its use for purposes other than
human drinking water (e.g. agriculture and other uses).
    As the highlighted portions of the SDWA regulations below show,
there is no requirement to demonstrate poor water quality prior to
issuing an aquifer exemption if the aquifer is or could be mineral
producing. Under the SDWA's UIC regulations, aquifer exemptions are
used to allow for mineral recovery in aquifers that would otherwise be
protected as sources of drinking water when certain criteria are met.
In the SDWA regulations, Sec.  146.4 provides that: ``An aquifer or a
portion thereof which meets the criteria for an ``underground source of
drinking water'' in Sec.  146.3 may be determined under Sec.  144.7 of
this chapter to be an ``exempted aquifer'' for Class I-V wells if it
meets the criteria in paragraphs (a) through (c) of this section. Class
VI wells must meet the criteria under paragraph (d) of this section:
(a) It does not currently serve as a source of drinking water; and (b)
It cannot now and will not in the future serve as a source of drinking
water because: (1) It is mineral, hydrocarbon or geothermal energy
producing, or can be demonstrated by a permit applicant as part of a
permit application for a Class II or III operation to contain minerals
or hydrocarbons that considering their quantity and location are
expected to be commercially producible; or (2) It is situated at a
depth or location which makes recovery of water for drinking water
purposes economically or technologically impractical; or (3) It is so
contaminated that it would be economically or technologically
impractical to render that water fit for human consumption; or (4) It
is located over a Class III well mining area subject to subsidence or
catastrophic collapse; or (5) The total dissolved solids content of the
ground water is more than 3,000 and less than 10,000 mg/l and it is not
reasonably expected to supply a public water system . . .''.
    In addition, although a portion of an aquifer may be exempted from
the protections of the SDWA, there are no federal requirements
preventing recovery and use of the water within exempted aquifers
(including where ISR operations were previously conducted) for private
drinking water supply, public water supply, or other uses.
    UMTRCA provides authority that can be used to protect aquifers
during and after uranium recovery operations, regardless of whether the
aquifer meets the definition of an underground source of drinking water
(USDW) as defined in the EPA's UIC regulations or is exempted from the
protections of the SDWA because it meets the existing regulatory
criteria for exemption. UMTRCA directs the Administrator to promulgate
``standards of general application for the protection of public health,
safety, and the environment from radiological and non-radiological
hazards associated with the processing, and possession, transfer, and
disposal of byproduct material''.\3\ The statute further provides that
``[i]n establishing such standards, the Administrator shall consider
the risk to the public health, safety, and the environment, the
economic costs of applying such standards, and such other factors as
the administrator determines to be appropriate''.\4\
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    \3\ See 42 U.S.C. 2022(b)(1).
    \4\ Ibid.
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    In areas being mined for uranium, the SDWA does not require
operators or regulators to collect the level of data needed to
definitively confirm or disprove drinking water contamination or
contamination of water for other purposes that may also impact humans,
such as livestock watering and crop irrigation. Additionally, data that
the EPA's UIC Program have received and evaluated at or near at least
one ISR facility are consistent with an excursion beyond the boundary
of the exempt aquifer (i.e., leading to elevated uranium levels outside
the ISR facility area).
    The proposed 40 CFR part 192, subpart F would afford protections
that do not currently exist under federal UIC regulations and would be
complementary to existing regulations (e.g., UIC regulations) at
uranium ISR facilities. For example, these new provisions proposed
under the authority of UMTRCA would address corrective action, broad
baseline development, monitoring well placement and aquifer
restoration. The proposed provisions would also provide assurance that
once

a facility decommissions a site, the water will meet the applicable
constituent concentration standards in 40 CFR 192.52(c)(1) and will
remain stable over time.
    The proposed 40 CFR part 192, subpart F also would ensure that
industry maintains responsibility for protection of public health and
the environment at uranium ISR facilities during and after uranium
recovery operations.
    Since ISR alters the chemical composition of groundwater, it
creates reasons to be concerned about risk to public health, safety and
the environment from radiological and non-radiological hazards
associated with the processing and disposal of byproduct material.
Industry commenters and others say that there is no need for this rule
because the EPA has not identified an instance in which an ISR
operation has contaminated a source of drinking water. First, the
Agency notes that this proposal addresses groundwater protection at ISR
facilities both in and around the production zone and in surrounding
aquifers. Focusing on the area of surrounding or adjacent aquifers, the
EPA acknowledges that the Agency does not have sufficient information
to document a specific instance of contamination of a public source of
drinking water caused by an ISR. The Agency remains concerned, however,
that the available data may not be capturing some instances of
contamination that this proposed rule seeks to prevent. In other words,
the Agency remains concerned that the lack of data does not demonstrate
that no contamination is occurring, as industry commenters assert, but
instead merely demonstrates the lack of data available to be able to
make such a determination, especially where there has been limited
post-restoration monitoring. The monitoring requirements in this
proposal address the issue of lack of data.
    As explained in this preamble, in documents supporting this
proposal, and as included in the docket for this proposal, there is
ample evidence of excursions occurring as the result of ISR facilities.
For example, data that the EPA's UIC Program have received and
evaluated at or near at least one ISR facility are consistent with an
excursion beyond the boundary of the exempt aquifer, leading to
elevated uranium levels outside the ISR facility. In addition, there is
data in the proposal's Background Information Document (BID) describing
numerous excursions from several ISR facilities. Moreover, data in
attachment 5 of the BID shows that several ISR facilities have not met
background or health-based levels after restoration of the production
zone. This data, when considered with the understanding that
groundwater flow is often extremely slow, raises concerns that there
has been insufficient monitoring conducted by these ISR facilities to
identify the actual contamination that may be occurring or may occur in
the future beyond the production zone and in sources of drinking water.
The EPA solicits comment on industry's assertion that in no case have
any excursions from ISR facilities resulted in contamination in
aquifers being used as public sources of drinking water or for other
uses. In addition, the EPA also requests comment on the kinds of data
that would be needed to clearly link ISR operations with off-site
contamination or that would support claims that there is no
contamination of concern.
    The EPA notes that several NRC-regulated ISR facilities are
continuing to work toward restoring groundwater, with restoration and
monitoring being conducted for as long as 10 years after ceasing
production. The Agency understands that restoration does not always
meet original background levels as evidenced by the number of
restoration goals exceeding background or the levels proposed in Table
1 to subpart F. Additionally, the NRC acknowledges that efficiency
could be gained by codifying its longstanding effective regulatory
regime into regulations specific to ISR facilities. Historically,
restoration and monitoring at ISR facilities are typically conducted
for only a short period, and a longer period would provide more
confidence to demonstrate that restoration of the affected groundwater
is complete and that long-term stability is established with confidence
before license termination. The initial and long-term stability
monitoring and corrective action program included in this proposal
would ensure that both of these requirements are met before ISR
facilities can be decommissioned.
    At ISR facilities, the groundwater is directly impacted by the
injection of lixiviant into the aquifer, which alters the geochemistry
of the ore-bearing formation and increases the concentration of
radionuclides and other metals in the water. Restoration activities
attempt to restore the water quality for specific constituents to the
applicable constituent concentration standards inside the production
zone. Although subpart D to 40 CFR part 192 (hereinafter ``subpart D'')
addresses contamination of aquifers, it explicitly addresses only
contamination resulting from releases from uranium mill tailings
impoundments used to store uranium byproduct material (e.g.,
conventional tailings impoundments, evaporation or holding ponds).
Under the proposed subpart F, the licensee is required to restore
groundwater in the production zone and surrounding aquifers to the
applicable constituent concentration standards, to the extent possible,
and to show some level of stability in the production zone prior to
terminating the license. Because ISR changes the geochemistry of the
groundwater, more rigorous stability-based standards together with
corrective action programs are necessary to ensure that the production
zone is restored and the applicable constituent concentration standards
will continue to be met in the future.
    As described in the preamble to the 2015 proposal, the EPA
solicited technical advice on key issues related to groundwater
protection at ISR sites from the Radiation Advisory Committee (RAC) of
the Agency's Science Advisory Board (SAB) (80 FR 156). The final report
of the SAB/RAC, along with the EPA's response, can be found at: https://yosemite.epa.gov/sab/sabproduct.nsf/c91996cd39a82f648525742400690127/0314cef928df63cc8525775200482fa3!OpenDocument&TableRow=2.4#2.
    The SAB/RAC further considered this issue in 2015, and the Agency
provided a detailed cross-walk to the 2015 proposed rule to show how
the RAC's advice had been addressed. The SAB determined that no further
action was needed on its part. See https://yosemite.epa.gov/sab/
sabproduct.nsf/02ad90b136fc21ef85256eba00436459/
8DA59AB1BE0EA14B85257E660071F2EF/$File/EPA-SAB-15-009+unsigned.pdf. In
general, the BID addresses topics specifically addressed by the RAC as
follows:
    The EPA has evaluated available data for all phases of ISR
activities to address the SAB recommendations. Section 5 of the BID
analyzes data and examines specific case studies for baseline and
restoration, with particular attention given to establishment of
baseline at the Dewey-Burdock site in South Dakota (Attachment A).
Sections 6 and 7.8 and Attachment F provide extensive analysis of post-
restoration monitoring at the Crow Butte, Christensen, Highland, and
Irigaray ISR sites, including regression analysis and statistical
testing, and cumulative complementary distribution functions (CCDF).
Results are presented by analyte, mine unit, and well.
    Section 6 addresses in detail SAB recommendations related to
influences on groundwater chemistry and their effects on time frames
for stability

monitoring, in particular fate and transport processes (speciation,
including a case study of the Crow Butte facility, and solubility) and
natural attenuation processes (adsorption, presence of secondary
minerals, and biological mechanisms).
    This action also proposes amendments to certain provisions in the
current rule, located at 40 CFR part 192. Specifically, this action
addresses a ruling of the Tenth Circuit Court of Appeals, updates a
cross-reference to another environmental standard and corrects other
technical and typographical errors.

C. Summary of the Major Provisions

    The proposed rule includes a new subpart, subpart F, within 40 CFR
part 192, which sets standards to protect groundwater at uranium ISR
operations. Specifically, subpart F would set standards of general
application to protect groundwater beyond the production zone during
ISR operational and restoration phases and to ensure, once the
wellfield is restored, that the restoration is complete and stable. The
proposed rule includes three types of groundwater protection standards:
(1) Constituent concentration standards, (2) initial stability
standards, and (3) long-term stability standards. The proposed rule
also includes monitoring requirements to establish statistically valid
background water quality levels, excursion monitoring (for the
operational and restoration phases), and monitoring to meet the initial
and long-term stability standards. The proposed rule also includes a
requirement to establish a corrective action program. Once finalized,
these standards will be implemented by the regulatory agency. Once the
regulatory agency incorporates the new standards into its regulations,
or takes other appropriate steps to implement the new standards, this
will provide a nationally consistent approach for the licensing process
for ISR facilities.\5\
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    \5\ Currently, the process used by the NRC for licensing ISR
facilities is based on a combination of NRC regulations, site-
specific license conditions, and guidance. The process used by the
Agreement States is based on regulations that vary by state for
Agreement States that regulate ISR facilities. The NRC and many of
the Agreement States have an established hearing process that allows
for interested parties to request a hearing on the merits for the
issuance and amendment of ISR facility licenses.
---------------------------------------------------------------------------

D. Summary of the Costs and Benefits

    The costs and benefits of this rulemaking are described briefly in
Table 2 of this preamble. The costs reflect the difference in costs
that would be incurred by ISR licensees under the proposed rule and
costs that would be incurred by those facilities in the absence of the
proposed rule. These incremental costs include added costs associated
with monitoring and non-monitoring compliance actions under the
proposed rule. For additional details on the incremental costs of the
proposed rule, see section V.B of this preamble and section 3 of the
document titled, ``Economic Analysis: Revisions to the Health and
Environmental Protection Standards for Uranium and Thorium Mill
Tailings Rule (40 CFR part 192),'' available in Docket ID No. EPA-HQ-
OAR-2012-0788.
    Complying with the proposed standards may require some existing ISR
facilities to monitor groundwater for additional constituents that they
are not currently monitoring. It would also require all ISR facilities
to continue monitoring for a period of at least three years after the
initial stability standard is met, and to conduct geochemical modeling
and other analysis to demonstrate that the applicable constituent
concentration standards will continue to be met in the future. The
additional monitoring, modeling and analysis that would be required
under this proposed rule could increase costs to ISR facilities. The
additional years during which ISR facilities' license, surety,
insurance, maintenance and other non-monitoring activities would have
to be maintained would also increase costs. The EPA estimates the rule
imposes annualized incremental costs on the ISR industry of
approximately $11.9 million, including incremental monitoring costs and
other non-monitoring costs.
    In its economic analysis, the EPA analyzed potential economic
impacts of the rule on small entities (7 companies) using a range of
assumptions about revenues of firms that own ISR facilities and costs
of complying with the rule. The ``average revenue'' assumption is based
on a market price of $55 per pound of U3O8e and production that is 25%
of facility capacity. The ``low revenue'' assumption reflects revenues
10% lower, and the high revenue assumption reflects revenues that would
be 20% higher. With average costs, cost-to-sales ratios for small firms
range from 0.7% to 3.1% for the low revenue scenario and from 0.5% to
2.3% under the higher revenue scenario. These assumptions are intended
to reflect the range of possible market conditions at the time when the
rule would take effect (likely 2022 to 2025). Uranium market
projections for the longer term are generally optimistic, reflecting
growth in nuclear power in China and India and other countries; 57 new
reactors are currently under construction with 65% of those projected
to come online by 2020, and world-wide electricity consumption is
projected to increase by 50% between 2013 and 2035 (only part of the
increase is estimated to be met by nuclear energy) (Cameco, 2016).
Outlook for the near term, however, is less positive, and the rate of
recovery is uncertain.
    The EPA acknowledges that current uranium market conditions reflect
depressed demand for uranium (due to lingering effects of the Fukushima
incident, slow recovery of demand for electricity since the recession
and low prices of substitute sources of energy) and some reliance on
alternative (non-mine) sources of uranium. As a result, both the price
and production of uranium have fallen. The long-term contract price of
uranium has declined from around $60 per pound of U3O8e in 2012 to
around $40 per pound in 2016. Spot prices have generally been 20% lower
than contract prices. While market forces have driven the market price
for uranium down by $20 to $30 dollars over the past 5 years, the rule
is estimated to increase the cost of producing uranium using ISR
methods by between $1.27 per pound U3O8e and $2.45 per pound of U3O8e,
depending on the cost scenario.
    Because of these market conditions, several ISR facilities that are
fully licensed and permitted are not currently producing uranium
(including previously operational facilities that have been placed on
standby and licensed and permitted facilities that have never gone into
production), and development of new ISR facilities has largely been put
on hold. Further, several ISR facilities have changed ownership in the
past few years, as companies have been forced by market conditions to
sell assets. In other words, some ISR firms currently are unable to
profitably operate their facilities even in the absence of the rule.
Several of the small firms report little or no revenue from sales of
uranium. Even the relatively small incremental costs required to comply
with the rule's provisions would not currently be affordable for such
firms. This is not due to the magnitude of the rule's costs; it is due
to current conditions in the world's economy generally and in the
market for uranium in particular. The EPA considers that when the
market for uranium recovers, as it is projected to do, ISR uranium
production and price will increase; under those conditions, facilities
that are currently unprofitable without the rule would likely be
profitable with the rule's costs included. However, the EPA solicits
public

comment on this rule's expected impact on the domestic ISR industry.
    The EPA compared these costs to the potential financial, ecological
and human health benefits that would result from the proposed rule.
Although the EPA is unable to quantify all the potential benefits, the
EPA has identified several categories of benefits that can be
attributable to the rule. The proposed rule would require groundwater
at ISR facilities to be restored to the constituent concentration
standards. Licensees would have to demonstrate stability of groundwater
at those constituent concentration standards by completing at least 6
years of monitoring (3 years to meet the initial stability standards
plus 3 years to meet the long-term stability standards), and conduct
modeling and analysis to demonstrate there is a reasonable assurance
that the applicable constituent concentration standards will continue
to be met in the future. This provision would minimize the risk of
degradation of valuable groundwater resources and the potential
exposure of human, domestic livestock or ecological receptors to
radiological or other constituents. The proposed rule would also
minimize the potential contamination of surface water and potential
adverse health impacts resulting from such contamination. In addition,
the proposed rule would avoid the potential costs associated with
remediating contaminated aquifers; the cost of remediating a single
plume of contamination could exceed the nationwide incremental costs
associated with the proposed rule. The EPA estimated the cost savings
due to avoided pump and treat remediation for hypothetical contaminant
migration examples using the Conceptual Mine Unit, under three plume
scenarios. For each scenario, the EPA computed the estimated cost
savings by computing the difference in the cost of remediating a large
plume (which might result if the plume were not detected for many
years) and the cost of remediating a small plume discovered through
monitoring prior to facility closure. The total estimated avoided costs
over the entire remediation episode in this illustration, remediating
three different sized plumes, ranged from $23.7 million to $608
million, depending on the scenario. Annualized, these avoided costs
range from $1.5 million to $11.1 million per year. To reflect the
recognition that the proposed rule would reduce the likelihood of
contamination relative to existing regulatory requirements, but not
eliminate it entirely, the EPA further assumed a range of probability
that the illustrative example contamination episode would be prevented
by the proposed rule, but not identified under current requirements.
The EPA assumed that the likelihood that the proposed rule would
prevent the contamination, but current requirements would not, would
range from 20% to 80%. Thus, the values shown in the table are 20% of
the lower bound value ($0.3 million) to 80% of the upper bound value
($8.9 million). However, because the EPA is unable to quantify the
number or characteristics of contamination episodes that could occur in
the absence of the proposed rule, the EPA is unable to estimate
nationwide cost savings. Thus, the EPA has not compared these
illustrative costs savings with the estimated national costs of the
proposed rule or computed the net benefits.

 Table 2--Characterization of the Costs and Benefits of 40 CFR Part 192,
                                Subpart F
------------------------------------------------------------------------
   Incremental costs  (2015 dollars)                 Benefits
------------------------------------------------------------------------
Annualized costs of monitoring,          Protection of groundwater
 modeling and analysis ranging from       quality.
 $0.2 to $7.3 million.
Annual non-monitoring costs, including   Possible protection of surface
 license, surety, lease, maintenance:     water quality.
 $7.6 million.
                                         Potentially reduced risk of
                                          exposure of human or
                                          ecological receptors to
                                          radiological pollutants.
                                         Potentially reduced human
                                          health impacts, including
                                          cancer.
                                         Annualized avoided cost of
                                          single remediation effort
                                          would be between $0.3 million
                                          and $8.9 million.\1\
------------------------------------------------------------------------
\1\ The costs presented are not an estimate of the nationwide
  remediation cost savings. They are the estimated cost of remediation
  for a simplified example of a single wellfield, for three contaminant
  plume scenarios.

E. Statutory Authority for This Action

    The EPA is proposing the new standards and amendments under its
authority in section 275 of the Atomic Energy Act (AEA), as added by
section 206 of UMTRCA.\6\ Section 206 of UMTRCA authorizes the EPA to
promulgate standards of general application for the protection of
public health, safety, and the environment from radiological and non-
radiological hazards associated with (a) residual radioactive materials
located at specifically listed inactive uranium milling sites, nearby
contaminated ``vicinity properties,'' and depository sites for such
materials selected by the Secretary of Energy (commonly referred to as
Title I sites); and (b) the processing and the possession, transfer and
disposal of byproduct material at sites that process ores primarily for
their uranium and thorium source material content \7\ or disposal of
such byproduct material (commonly known as Title II sites). See 42
U.S.C. 2022.\8\ These public health, safety and environmental standards
are contained in 40 CFR part 192 and are implemented by the NRC and its
Agreement States, as well as the DOE.
---------------------------------------------------------------------------

    \6\ See 42 U.S.C. 2022.
    \7\ ``Source material'' is defined as ``(1) Uranium or thorium
or any combination of uranium or thorium in any chemical or physical
form; or (2) Ores that contain, by weight, one-twentieth of one
percent (0.05 percent), or more, of uranium or thorium, or any
combination of uranium or thorium.'' See 42 U.S.C. 2014(z), 10 CFR
20.1003.
    \8\ Although the statute covers both uranium and thorium mill
tailings sites, there are no existing thorium mill tailings sites.
---------------------------------------------------------------------------

    Title I of UMTRCA covers inactive uranium milling sites, nearby
contaminated ``vicinity properties'' and depository sites. The EPA was
directed to set general standards that are consistent with the
requirements of the Solid Waste Disposal Act (later amended as the
Resource Conservation and Recovery Act, or RCRA) to the maximum extent
practicable. The Title I standards are located in EPA regulations at 40
CFR part 192, subparts A-C.
    This proposed rule is based on Title II of the Act, which covers
operating uranium processing or disposal facilities licensed by the NRC
or NRC Agreement States. The EPA has authority to promulgate standards
of general

application to protect public health, safety and the environment from
hazards associated with processing, possession, transfer and disposal
of byproduct material at such facilities. Such standards must address
both radiological and non-radiological hazards; further, standards
applicable to non-radiological hazards must be consistent with the
standards required under Subtitle C of the Solid Waste Disposal Act
(i.e., RCRA).\9\ The NRC is required to implement these standards at
Title II sites. See 42 U.S.C. 2022(b), (d).
---------------------------------------------------------------------------

    \9\ With the restriction that the EPA not require any RCRA
permit for the processing, possession, transfer or disposal of
byproduct material at such facilities.
---------------------------------------------------------------------------

II. Summary of the Proposed Rule

A. Proposed Standards for Uranium ISR Operations

    In today's action, the EPA is proposing to add a new subpart,
subpart F, to the EPA's existing regulations for uranium and thorium
mill tailings in 40 CFR part 192. The proposed standards would apply
only to ISR facilities and are designed to protect public health,
safety and the environment from contamination associated with their
uranium recovery operations. The proposed standards are summarized in
the following sections.
1. Who is subject to the proposed standards?
    Subpart F would apply to new and existing ISR facilities, including
facilities that have temporarily ceased uranium production (i.e., ISR
facilities in standby). Subpart F would not apply to Title I sites,
facilities that use only conventional or heap leach uranium production
methods, or Title II ISR wellfields that have already begun or
completed restoration within three years of the rule's effective date.
The NRC and NRC Agreement States would develop regulations or take
other appropriate steps to implement the new subpart F standards, once
they are finalized.
2. What are the proposed surface and groundwater standards for ISR
facilities?
    In the proposed new subpart, the EPA has cross-referenced subpart D
to indicate that the existing standards for protecting surface waters
and groundwater also apply to ISR facilities. The subpart D standards
were initially written to address the handling, storing and disposal of
byproduct material produced from the processing of uranium ore.
3. What are the proposed groundwater protection standards for ISR
facilities?
    Consistent with the original proposal, this proposed rule includes
the following three types of groundwater protection standards for ISR
facilities: (1) Constituent concentration standards (including
provisions for Alternate Concentration Limits (ACLs)); (2) initial
stability standards; and (3) long-term stability standards.\10\ These
standards of general application would apply to all ISR facilities and
are intended to prevent the mobilization of uranium and other
constituents beyond the production zone during the operational and
restoration phases and to ensure, once the wellfield is restored, that
the restoration is complete and stable, both immediately after
restoration and into the foreseeable future.
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    \10\ The initial stability standards and the long-term stability
standards were originally included in the proposed monitoring
programs section of the rule. The initial stability standards
(called ``short-term stability'' in the proposal) was proposed in 40
CFR 192.53(d)(2)(i) and the long-term stability standards were
proposed in 40 CFR 192.53(e)(1)(iii). To improve clarity, the
initial and long-term stability standards have been moved to 40 CFR
192.52(c)(2) and (c)(3), respectively.
---------------------------------------------------------------------------

    Constituent Concentration Standards. The constituent concentration
standards are numerical concentration limits for a set of groundwater
constituents that are present in or affected by ISR operations. When
corrective action is necessary after an excursion has occurred, the
licensee would have to clean-up the groundwater to meet these proposed
constituent concentration standards. In addition, during the
restoration and stability monitoring phases, these proposed constituent
concentration standards would be the levels to which restoration must
be achieved and maintained.
    In this proposal, the appropriate constituent concentration
standards for an ISR facility would be determined by the regulatory
agency for each licensee. The constituent concentration standard for
each constituent would be the highest level of the following values:
(1) The lowest regulatory standard for that constituent found in 40 CFR
141.62, 141.66, 141.80, 143.3, 264.94, and Table 1 to subpart A of 40
CFR part 192; (2) that constituent's preoperational background level in
the wellfield; or (3) an ACL for that constituent as approved by the
regulatory agency. When setting the constituent concentration standards
for a licensee, the regulatory agency would consider a minimum of 12
constituents. The regulatory agency would not be required to set
standards for all 12 constituents, but the regulatory agency would have
to set a constituent concentration standard for each of the listed
constituents that is present in or could be affected by the ISR
operation. The regulatory agency would have to identify the
constituents during the preoperational monitoring phase. The regulatory
agency would need to consider the following 12 constituents when
setting the constituent concentration standards for an ISR operation:
Arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver,
nitrate (as N), molybdenum, combined radium-226 and radium-228, and
uranium (total). The original proposal included gross alpha particle
activity (excluding radon and uranium), however, this constituent was
not included in this proposal for the reasons explained in section
III.3.2. The EPA is specifically requesting comment on the deletion of
gross alpha particle activity (excluding radon and uranium) from the
list of constituents. The regulatory agency may also set constituent
concentration standards for additional constituents beyond these 12
constituents for situations where the regulatory agency considers
concentration standards for other constituents necessary due to
facility-specific conditions.
    Once these proposed standards are finalized and the regulatory
agency implements the subpart F standards, the constituent
concentration standards would have to be established in accordance with
the provisions in Sec.  192.52 for all new wellfields and expansions to
existing wellfields, and for all existing wellfields that are already
operating, excluding those that are in and remain in the restoration
and stability monitoring phases, as of the date three years after the
effective date of this rule. Wellfields that begin and remain in
restoration, initial stability monitoring or long-term stability
monitoring at a licensed facility prior to the date three years after
the effective date of the rule would need to meet the standards
established when their license was issued or as otherwise specified by
the regulatory agency.
    Alternate Concentration Limits. Consistent with the original
proposal, this proposal would allow licensees the flexibility to
request ACLs when the best practicable active restoration has taken
place, as determined by the regulatory agency, and the licensee
demonstrates one or more of the constituent concentration standards
cannot be met through further groundwater restoration. The best
practicable active restoration must be used before the licensee can
apply to the regulatory agency for a provisional ACL. Under this
proposal, once the regulatory

agency establishes a provisional ACL, and the licensee can demonstrate
the ACL has been met for three consecutive years, the regulatory agency
can consider finalizing the ACL.
    It must be understood that granting an ACL is an indication that
restoration has not returned the affected groundwater to either
preoperational background levels or other health-based levels. However,
there are some overarching principles that must be considered when
establishing ACLs. In general, as described in Sec.  192.54, any
provisional or final ACL should not pose a substantial present or
potential hazard to human health and the environment, as determined by
the regulatory agency. Points of exposure are defined in the proposal
as locations identified by the regulatory agency that represent
possible future areas of exposure where the receptor can come into
contact with groundwater (e.g., areas of recoverable groundwater). The
groundwater at the point of exposure should be protective of the
receptor. The EPA specifically requests comment on this approach,
especially with regard to the overall regulatory model of how ACL
application would work, the definition of points of exposure and the
use of this term, and the overall environmental, human health and
safety protection goals for setting and using ACLs. Commenters,
including interagency commenters, raised questions concerning the
integration of an aquifer exemption under the SDWA and point of
exposure as it was defined in the EPA's original proposal and the
differing jurisdictions of the SDWA and UMTRCA.
    Under this proposal, when considering setting an ACL, the
regulatory agency would consider a list of factors, including potential
adverse effects on groundwater quality, physical and chemical
characteristics of the constituent, including the potential for
migration, hydrogeological characteristics of the area, proximity and
withdrawal rates of local groundwater users, current and anticipated
future uses of the groundwater, existing quality of the groundwater,
potential for health risks, potential to damage wildlife, crops,
vegetation and physical structures, the persistence and permanence of
the potential effects, adverse impacts on hydraulically connected
surface water (including several factors) and the presence of any USDW.
    The EPA expects that setting a provisional and final ACL will
require consideration of the hydrologic and other characteristics of
the wellfield and surrounding area, any potential areas of groundwater
withdrawal or discharge and be protective of human health into the
foreseeable future.
    Consistent with UMTRCA, the Tenth Circuit Court of Appeals in the
Environmental Defense Fund v. NRC decision,\11\ and current practice,
the regulatory agency would be responsible for reviewing and approving
ACL requests. Although not a proposed provision, the EPA considers it
good practice for the regulatory agency to make public the information
used for determining whether a provisional ACL is warranted and at what
concentration before approving a provisional ACL. Although the NRC has
not issued an ACL to date for an ISR wellfield, the NRC current
practice would result in making such information publicly available and
would support the EPA's effort to increase the effectiveness of the
rule.
---------------------------------------------------------------------------

    \11\ 866 F.2d 1263 (10th Cir. 1989).
---------------------------------------------------------------------------

    Stability Standards. In addition to the constituent concentration
standards discussed above, licensees would also need to meet initial
and long-term stability standards. The initial stability standards
would require three consecutive years of quarterly monitoring results
showing no statistically significant increasing trends exceeding the
ISR facility's constituent concentration standards at the 95 percent
confidence level. The long-term stability standards would require an
additional three consecutive years of quarterly monitoring results
showing no statistically significant increasing trends exceeding the
ISR facility's constituent concentration standards at the 95 percent
confidence level and also would require the licensee to demonstrate
through geochemical modeling and other analysis that the applicable
constituent concentration standards will continue to be met in the
future. Consistent with the original proposal, the regulatory agency
issuing the license would be responsible for determining whether there
is reasonable assurance that the applicable constituent concentration
standards will continue to be met at the ISR facility in the future.
4. What are the proposed general and preoperational monitoring
requirements?
    In order to understand the hydrogeology and geochemistry of the
production zone and surrounding area and to set the preoperational
background for the constituent concentration standards, licensees would
develop a preoperational monitoring plan for the wellfield. The
preoperational monitoring plan would characterize the hydrogeology and
geochemistry of the area, support identification of any potential
future excursions from the production zone during the operational and
restoration phases, and support the monitoring, modeling and other
analysis as determined by the regulatory agency to be necessary to meet
the proposed initial and long-term stability standards.
    The preoperational monitoring determines the groundwater flow
regime and the background groundwater concentrations of the 12 listed
constituents and any additional constituents required by the regulatory
agency. The data collected during this period would be used to select
the indicator parameters and set the upper control limits (UCLs) for
these parameters. The indicator parameters would be monitored during
the operational and restoration phases and, when the UCL is exceeded,
indicate that lixiviant or other constituents are migrating beyond the
production zone. The preoperational monitoring would be conducted at
wells within the production zone and in areas surrounding the
production zone, including aquifers immediately above and below the
production zone, and in areas laterally adjacent to the production
zone, both up and down gradient. A sufficient number of wells would
have to be installed and monitored so that the sampling data collected
could be used to statistically determine appropriate background levels
and support statistical tests, modeling and other analysis determined
by the regulatory agency to be necessary during the operational,
restoration, initial stability and long-term stability phases. The
licensee would collect a sufficient number of sample sets per well over
a time period sufficient to indicate a statistically valid background
concentration that is not affected by well installation or temporal
variations. In areas where temporal (e.g., seasonal) variation could
occur (e.g., ore zones in unconfined aquifers), the preoperational
monitoring would be conducted for at least one year in a sufficient
number of wells to adequately represent the hydrologic system.
    In addition to monitoring the concentrations of the constituents
required by the regulatory agency, the licensee would collect any other
data necessary to establish background conditions to support future
modeling and other analysis in preparation to meet the proposed long-
term stability standards in Sec.  192.52(c)(3).

5. What are the proposed monitoring requirements for the operational
and restoration phases?
    To ensure that no lixiviant, uranium or other constituents are
migrating outside of the production zone, the licensee would monitor
groundwater for specified indicator parameters at a set of monitoring
wells surrounding the production zone. These excursion monitoring wells
would be located around the perimeter of the production zone and in any
aquifers immediately above or below the production zone that may be
impacted by ISR activities. That is, the excursion monitoring wells
need to surround the production zone in three dimensions. The excursion
monitoring wells would be of sufficient number, density, and placement
to detect the possibility of an excursion from the production zone. The
regulatory agency would be responsible for reviewing and, when
appropriate, approving well placement and installation, indicator
parameters, the UCLs for the indicator parameters, as well as
background levels for constituents for which constituent concentration
standards are set.
    Typical indicator parameters used to identify possible excursions
include chloride, conductivity and total alkalinity. Other parameters
may be appropriate as well. In the proposed rule, an excursion has
occurred when either (1) two indicator parameters exceed their
respective UCLs in any excursion monitoring well; or (2) as determined
by the regulatory agency, one indicator parameter significantly exceeds
its UCL in any excursion monitoring well. The EPA specifically requests
comment on this proposed definition of an excursion and suggestions for
other approaches for determining when an excursion has occurred. If an
excursion occurs, the licensee would need to initiate corrective action
in accordance with its facility-specific corrective action program and
would be required to test for all constituents for which a constituent
concentration standard was established. At a minimum, the constituents
from Table 1 that are typically present and that warrant monitoring
during an excursion are uranium, radium, arsenic and selenium. The
regulatory agency would be allowed to identify additional constituents
that are present in the groundwater and need to be monitored on a
facility-specific basis.
    In some cases, a licensee may have temporarily stopped recovering
uranium and the facility may be in a phase commonly called ``standby''
by the industry. In such instances, the EPA considers the facility to
be in the operational phase and the licensee would be required under
the proposed rule to continue monitoring and taking actions, such as
maintaining an inward hydraulic gradient, to prevent excursions.
6. What monitoring is proposed for the initial stability standards?
    Once the licensee believes restoration is near completion and
believes they can, over time, demonstrate that the proposed initial
stability standards in Sec.  192.52(c)(2) can be met, the EPA expects
that the licensee would begin monitoring the groundwater constituent
concentrations throughout the wellfield to determine when the initial
stability standards have been met. To meet the proposed initial
stability standards, the licensee would need to demonstrate stability
by providing three consecutive years of quarterly monitoring results
showing no statistically significant increasing trend exceeding each
established constituent concentration standard. For all monitored
constituents, this trend would need to be demonstrated at the 95
percent confidence level. The licensee would be required to develop and
implement a compliance monitoring program approved by the regulatory
agency that identifies compliance points encompassing the entire
affected area of the wellfield.
    The purpose of the proposed stability monitoring is to determine
whether constituent levels in the entire affected area of the
wellfield, including the production zone, have returned to levels below
the established constituent concentration standards and stable
conditions are established. Hence, compliance wells must include wells
previously used as excursion monitoring wells and those previously used
as production related wells. The location of the compliance wells used
to determine compliance with the initial stability standards would need
to be approved by the regulatory agency and would need to be located in
areas likely to be affected by ISR operations. Therefore, compliance
well would be located within the production zone, adjacent to the
production zone and in aquifers located immediately above and below the
production zone, as approved by the regulatory agency. The number and
location of compliance wells will vary depending on the size and
characteristics of the wellfield, but should encompass the entire
affected area of the wellfield.
    To meet the proposed initial stability standards of Sec.
192.52(c)(2), measurements would need to be taken quarterly at each
well. If one or more constituents exceed a constituent concentration
standard during the initial stability monitoring, then the licensee
would follow the corrective action program approved by the regulatory
agency. When monitoring to assess whether the initial stability
standards have been met, constituent concentrations may fluctuate above
the respective standard. The corrective action program should address
the possibility of and the regulatory agency should consider potential
responses to an exceedance of the constituent concentration standards
while the licensee is establishing a statistically adequate trend. The
regulatory agency may allow continued monitoring, if appropriate, or
require the licensee to undertake a remedy. Regardless of the action
taken, the licensee would be required by the proposed standards to
achieve three consecutive years of stable measurements. Furthermore, as
in all phases, if lixiviant or other constituents escape the production
zone, the licensee would be required to take the necessary actions to
return the aquifer to below the constituent concentration standards.
    When the licensee demonstrates three consecutive years of quarterly
monitoring results showing no statistically significant increasing
trends exceeding the established constituent concentration standards at
the 95 percent confidence level, then the facility has met the proposed
initial stability standards and the licensee may, upon the
determination of the regulating agency that the initial stability
standards have been satisfied, begin long-term stability monitoring.
7. What are the proposed requirements for the long-term stability
standards?
    During the proposed long-term stability monitoring, the licensee
continues quarterly monitoring to demonstrate compliance with the
constituent concentration standards using the compliance wells
established for monitoring during the initial stability phase. To meet
the proposed long-term stability standards in Sec.  192.52(c)(3), the
licensee would need to first demonstrate quarterly monitoring results
for a minimum of three consecutive years showing no statistically
significant increasing trends exceeding the established constituent
concentration standards (including any approved ACLs) at the 95 percent
confidence level.
    To approve cessation of long-term stability monitoring, the
regulatory agency would be responsible for determining whether there is
reasonable

assurance that the applicable constituent concentration standards will
continue to be met at the ISR facility in the future. To make this
determination, an analysis of geochemical hydrologic and other
conditions within and around the production zone should be prepared by
the licensee and reviewed by the regulatory agency. The EPA requests
comment on the specificity of the regulatory language for this final
determination of stability and the elements to be considered. In
general, the EPA expects that the review should examine various
features within the production zone and use a combination of sample
collection and analysis of the restored production zone, data review,
geochemical modeling and analysis to integrate the various types of
data and to assess groundwater conditions. Various types of geochemical
models may be employed from saturation index calculations to reactive
transport models that can evaluate changing hydrologic and geochemical
conditions within the wellfield. The EPA believes the licensee's long-
term stability assessment should include the following elements:
    (i) Conceptual hydrogeochemical modeling for the mine unit/
production zone;
    (ii) Ground water and solid (core) data used for geochemical
model(s), including field parameters;
    (iii) Incorporation of ground water data in an initial geochemical
model (i.e., saturation indices calculations and assessment);
    (iv) Demonstration that stability (mainly reduction-oxidation or
redox) conditions can be maintained in the production zone;
    (v) Demonstration that ground water migrating into the production
zone will not significantly change the geochemical stability within the
production zone;
    (vi) Demonstration of alternative geochemical conditions that
demonstrate stability (uranium and other elements); and
    (vii) Inter-relationships and contradictory claims (unintended
consequences) for these various elements need to be identified and
assessed in the context of the conceptual hydrogeochemical model.
    The EPA requests comment on whether these seven elements should be
required at all sites and thus included in the standards in 40 CFR part
192, subpart F.
    The regulatory agency has the responsibility to establish the
timeframe for long-term stability monitoring, based on facility-
specific conditions at the wellfield and the results of long-term
stability monitoring, modeling and analysis. If one or more
constituents exceed their concentration standard (or approved ACL) or
show a statistically significant increasing trend during the long-term
stability phase, the regulatory agency may require the licensee to take
corrective action as specified in the facility's corrective action
program.
8. What are the proposed corrective action requirements?
    Each licensee would be required to develop a corrective action
program that addresses the actions it will take when an excursion is
detected during the operational and restoration phases, or when
monitoring during the stability phases shows a concentration higher
than the established constituent concentration standard or a
statistically significant increasing trend. Corrective action, as
identified in the corrective action program and approved by the
regulatory agency, would be initiated as soon as practicable and would
begin within 60 days of the date the excursion or exceedance of a
constituent concentration standard is detected. The corrective action
program would consider a range of possibilities for action from the
operational phase through the long-term stability monitoring phase.
Corrective action may include removing or treating in place any
constituents that exceed the constituent concentration standards (or
approved ACL). If the concentration of one or more constituents exceeds
the constituent concentration standard (or approved ACL) during long-
term stability monitoring, the licensee would be required to take
corrective action to restore the groundwater to comply with the
proposed constituent concentration standards; once restoration is
complete, the licensee would begin again with initial stability
monitoring.

B. Proposed Amendments to 40 CFR Part 192, Subparts C and D

    As part of this rulemaking, the EPA is also proposing several minor
amendments to the provisions in 40 CFR part 192, subparts C and D.
These amendments are described in this section and are not related to
the new standards for ISR facilities added in 40 CFR part 192, subpart
F.
1. What are the proposed revisions to Sec.  192.32(a)(2)(v)?
    This proposed rule deletes the requirement in Sec.  192.32(a)(2)(v)
for the NRC to obtain concurrence from the EPA before the NRC may
approve alternative requirements or proposals under AEA section
84(c).\12\ As the EPA stated in the proposal, this portion of Sec.
192.32(a)(2)(v) was effectively struck down by the Tenth Circuit Court
of Appeals in Environmental Defense Fund vs. U.S. Nuclear Regulatory
Commission, 866 F.2d 1263 (10th Cir. 1989). In its decision, the Court
ruled that the NRC has authority under AEA section 84(c) to
independently make these facility-specific determinations, and that the
NRC has no duty to obtain the EPA's concurrence.
---------------------------------------------------------------------------

    \12\ See 42 U.S.C. 2114(c).
---------------------------------------------------------------------------

2. What are the proposed miscellaneous updates and corrections?
    The EPA is also proposing several minor amendments to subparts C
and D to correct cross-references, typographical and punctuation
errors. These amendments include the following:

------------------------------------------------------------------------
                                 Description of
          Section              proposed technical       Rationale for
                                   correction            correction
------------------------------------------------------------------------
                       40 CFR part 192, subpart C
------------------------------------------------------------------------
192.20(b)(3)...............  Delete reference to    The Grand Junction
                              ``Pub. L. 92-314 (10   Remedial Action
                              CFR part 712)''.       Criteria to which
                                                     this reference
                                                     applied no longer
                                                     exist in the CFR.
192.20(b)(3)...............  Delete language        Methods were found
                              referencing sealants   to be ineffective
                              and filtration.        and are no longer
                                                     recommended as
                                                     remedial options
                                                     for radon
                                                     mitigation.
------------------------------------------------------------------------
                       40 CFR part 192, subpart D
------------------------------------------------------------------------
Sec.   192.31(a)...........  Replace ``Uranium      Corrects a
                              Mill Tailings          typographical
                              Rediation Control      error.
                              Act'' with ``Uranium
                              Mill Tailings
                              Radiation Control
                              Act''.

Sec.   192.31(f)...........  Replace ``pile         Corrects a
                              containing uranium     typographical
                              by product             error.
                              materials'' with
                              ``pile containing
                              uranium byproduct
                              materials''.
Sec.   192.32(a)(2)(v).....  Replace ``laser        Corrects a
                              fusion, of soils,      punctuation error.
                              etc.'' with ``laser
                              fusion of soils,
                              etc.''.
------------------------------------------------------------------------

III. Summary of Changes Made to the Original Proposal and Rationale for
Those Changes

    As previously indicated, the standards proposed in today's action
differ from those standards proposed on January 26, 2015 (80 FR 4156).
This section of the preamble describes the most significant changes
made to the original proposal and the rationale for those changes. Many
of the changes were made in response to public comments and additional
information provided by stakeholders. In response to the original
proposal, the EPA received over 5,380 public comment letters on the
proposed amendments, of which 5,192 were duplicate letters. The
comments covered more than 80 different topics and were submitted by a
wide range of stakeholders, including private citizens, public interest
groups, industry, Indian tribes, state agencies and other federal
agencies. For the original proposal, the EPA also held public hearings
in Corpus Christi, TX (April 14, 2015); Washington, DC (March 10,
2015); Casper, WY (May 13 and 14, 2015); and Chadron, NE (May 12,
2015), where 114 stakeholders provided comments.
    In addition to describing the changes made to the original
proposal, this section also discusses and responds to the significant
comments that resulted in many of those changes. The significant
comments received that did not result in changes to the original
proposal are discussed in section IV of the preamble.

A. Incorporation of the Initial and Long-Term Stability Standards in
Proposed 40 CFR 192.52

    For clarity, the EPA has restructured the proposed rule to move the
initial and long-term stability standards that were originally included
with the monitoring requirements in Sec.  192.53 to the standards in
Sec.  192.52. The initial stability standards (called ``stability'' or
``short-term stability'' in the original proposal) were proposed in
Sec.  192.53(d)(2)(i), and the long-term stability standards were
proposed in Sec.  192.53(e)(1)(iii). In this proposal, the initial and
long-term stability standards have been moved to Sec.  192.52(c)(2) and
(c)(3), respectively.

B. Groundwater Protection Standards

1. Clarifications to Terminology
    The original January 2015 proposal listed 13 constituents for which
a facility-specific concentration limit must be set for each
constituent that is present in the groundwater. In the original
proposal, the EPA referred to these facility-specific concentration
limits as ``groundwater protection standards'' and ``restoration
goals'' (see Sec.  192.52(c) of the original proposed rule). Since the
use of these two terms may lead to confusion, the EPA is no longer
using the term ``restoration goals'' but is instead using the term
``constituent concentration standards'' throughout the proposed rule to
refer to these facility-specific concentration limits.
    In the original proposed rule, the EPA also used the phrase
``identified in the groundwater'' when referring to constituents for
which constituent concentration standards should be established (see
Sec.  192.52(c) of the original proposed rule). The EPA intended
concentration standards to be set for any constituent that is present
in groundwater before or after ISR activities have begun. Some
constituents may not be initially present in the groundwater but may
become soluble only after lixiviant is injected and groundwater
chemistry has been altered. However, the phrase ``identified in the
groundwater'' could be misinterpreted to mean only those that are
present during preoperational monitoring. For clarification, the EPA
has revised the original proposal to specify that constituent
concentration standards must be established for all constituents that
are ``identified as present or affected by operations in the
groundwater.''
2. Gross Alpha Particle Activity
    In the original proposal, the list of constituents in Table 1 of
subpart F included gross alpha particle activity.\13\ Several
commenters opposed listing gross alpha particle activity, stating that
it provided no useful information that could not be otherwise obtained
from the required measurement of radionuclides, such as radium 226. In
addition, commenters noted the wide uncertainty range for the
radiochemistry analytical methodology currently used to measure gross
alpha activity.
---------------------------------------------------------------------------

    \13\ The SDWA MCL of 15 pCi/L for gross alpha particle activity
excludes alpha particle activity contributions from radon and
uranium.
---------------------------------------------------------------------------

    The EPA tends to agree with commenters who suggested that gross
alpha measurements are likely to be of limited value when other
radionuclides of concern are also being sampled. The Agency also
recognizes that the uncertainty associated with gross alpha
measurements may be greater than those for other constituents, which
may make the application of statistical tests especially complicated.
However, gross alpha is specified as a constituent to be sampled in
other subparts of 40 CFR part 192, and it does have a maximum
contaminant level (MCL), which cannot be overlooked. Further, there may
be instances where gross alpha measurements provide information
regarding the presence of decay products such as lead and polonium. The
EPA is specifically requesting comment on the deletion of gross alpha
particle activity as one of the original proposal's 13 constituents,
whether it provides useful information, and how measurement uncertainty
might be addressed.

C. Preoperational Monitoring Requirements

    In the original proposal, the EPA included provisions for
preoperational monitoring that were designed to characterize the
groundwater flow regime, geology and geochemistry. The EPA originally
proposed that preoperational monitoring would measure the background
concentrations of radiological and non-radiological constituents,
including all the constituents listed in Table 1 of subpart F, and any
additional constituents or parameters specified by the regulatory
agency or needed for calculations or groundwater modeling. The original
proposal required preoperational monitoring be continued for a minimum
of one year in order to account for any temporal changes occurring in
the aquifer. The EPA also proposed some requirements for the location
of the wells, requiring monitoring wells to be located in overlying
aquifers, underlying aquifers, inside the exempted aquifer and outside
the exempted aquifer, including areas that

are up- and downgradient from the future production zone. The original
proposal specified standards for installing the monitoring wells,
including requirements for casings and for sealing the wells to prevent
contamination.
1. Duration of Preoperational Monitoring
    The EPA received a number of comments on the duration of the
proposed preoperational monitoring requirements. Some commenters
supported the one-year timeframe, while others recommended the time
period be extended to up to two years. Many commenters cited the NRC
Criterion 7 from 10 CFR part 40, Appendix A, which requires uranium
mills to complete one or more years of preoperational monitoring before
a company can submit a license application. Two commenters noted that
some aquifers do not experience seasonal variations in groundwater
constituents. For example, commenters asserted there may be no
seasonally influenced fluctuation in the concentrations of groundwater
constituents in deeper target ore production aquifers.
    Based on all of these comments, the EPA has refined the approach to
preoperational monitoring. Instead, the Agency is proposing that
preoperational monitoring of wells screened in areas where temporal
variations are not expected to occur, such as in deep ore zones in
confined aquifers, would be allowed to monitor for periods of less than
one year. However, the licensee would collect several sets of samples
over a time period sufficient to demonstrate seasonal variability does
not occur. For example, in some cases, four sets of samples collected
over several months would be adequate to determine the background for
systems that do not exhibit seasonal changes. In this proposal, sample
sets collected over a period of at least one year would still be
necessary for facilities that operate in areas where constituent
concentrations are expected to exhibit seasonal fluctuations. The
regulatory agency would determine whether the licensee's preoperational
monitoring is of sufficient duration and that sampling occurs at
appropriate intervals to establish the background concentrations for
all 12 constituents, as well other constituents identified by the
regulatory agency and all indicator parameters. To provide flexibility
where appropriate, the EPA did not propose an across-the-board two-year
monitoring requirement, although the regulatory agency would be allowed
to do what is necessary to reflect seasonal or other variation in
background constituent concentrations or flow.
2. Changes to the Well Completion Requirements
    The Agency received several comments on the original proposed
requirements for well completions. A general concern expressed by the
commenters is that true baseline conditions of the groundwater
constituents cannot be established if the well drilling and development
methods introduce oxygen into the groundwater. The commenters explained
that since oxygen may increase the solubility of uranium, elevated
baseline concentrations will lead to artificially high restoration
goals. Commenters suggested several methods to alleviate this concern,
including air-rotary drilling with recirculated nitrogen gas instead of
air and a foam surfactant that contains organic constituents to
eliminate oxygen.
    After considering these comments, the EPA believes sufficient
monitoring should be completed to ensure all perturbations associated
with well construction are resolved prior to establishing the
background concentrations. To achieve this goal, under this proposed
action, the licensee would collect several sets of samples over a time
period sufficient to demonstrate baseline conditions that are
unaffected by monitoring well construction. In the proposal, the EPA
requires the sampling frequency to be sufficient to ensure
statistically valid background levels that are not influenced by well
construction. The samples used for this purpose may be the same as
those used for the temporal variability analyses, if technically
feasible. The regulatory agency would determine whether the licensee's
well construction follows appropriate protocols and that sampling
occurs at appropriate intervals to establish accurate background
concentrations.

D. Exempted Aquifers

    The EPA originally proposed that preoperational monitoring wells,
excursion monitoring wells used during the operational and restoration
phases, and compliance wells used during the initial and long-term
stability monitoring phases (referred to as ``point(s) of compliance'')
be located inside and outside of ``exempted aquifers'' (see the
proposed definition for ``point(s) of compliance'' at 80 FR 4184). In
the original proposal, the EPA also defined the term ``point(s) of
exposure'' as the ``intersection of a vertical plane with the boundary
of the exempted aquifer'' and the term ``adjacent aquifer'' as an
aquifer or portion of an aquifer that ``shares a border or end point
with the exempted aquifer or the exempted portion of an aquifer'' (see
80 FR 4183-4184). As the EPA explained in the original proposal, the
term ``exempted aquifer'' refers to aquifers that are exempted from the
protections afforded by the SDWA (see 80 FR 4160).
    Under the SDWA, the EPA sets health-based standards for drinking
water to protect against naturally occurring and anthropogenic
contaminants that may be found in surface and groundwater sources of
drinking water. Additionally, under SDWA authority, the EPA promulgated
Underground Injection Control (UIC) Program regulations to ensure
protection of USDWs,\14\ which may be consumed now or in the future,
where injection activities are occurring. The UIC regulations at 40 CFR
144.12 prohibit any injection activity that allows the movement of
fluid containing any contaminant into USDWs if the presence of that
contaminant may cause a violation of any primary drinking water
standard or otherwise adversely affect the health of persons. Under UIC
Program regulations, an aquifer or a portion of an aquifer may be
exempted from the protections afforded USDWs, under the SDWA, if (a) it
does not currently serve as a source of drinking water; and (b) it
cannot now and will not in the future serve as a source of drinking
water because one of four specified conditions is met, or (c) the total
dissolved solids content of the groundwater is more than 3,000 mg/L and
less than 10,000 mg/L and it is not reasonably expected to supply a
public water system (see Sec.  146.4). The four conditions referenced
above for the aquifer exemption criteria at 40 CFR 146.4(b) are:
---------------------------------------------------------------------------

    \14\ USDWs are defined, by regulation at 40 CFR 144.3, as: ``An
aquifer or its portion: (a)(1) Which supplies any public water
system; or (2) Which contains a sufficient quantity of ground water
to supply a public water system; and (i) Currently supplies drinking
water for human consumption; or (ii) Contains fewer than 10,000 mg/l
total dissolved solids; and (b) Which is not an exempted aquifer.''
---------------------------------------------------------------------------

    (1) It is mineral, hydrocarbon or geothermal energy producing, or
can be demonstrated by a permit applicant as part of a permit
application for a Class II or III operation to contain minerals or
hydrocarbons that considering their quantity and location are expected
to be commercially producible.
    (2) It is situated at a depth or location which makes recovery of
water for drinking water purposes economically or technologically
impractical;

    (3) It is so contaminated that it would be economically or
technologically impractical to render that water fit for human
consumption; or
    (4) It is located over a Class III well mining area subject to
subsidence or catastrophic collapse.
1. Removal of References to ``Exempted Aquifer''
    In this proposal, the EPA has removed references to ``exempted
aquifers'', deleted the definitions of ``adjacent aquifer'' and
``exempted aquifer'' from Sec.  192.51, and removed the phrase
``exempted aquifer'' from the definition of ``background'' in Sec.
192.51 and from the requirements specifying where monitoring wells must
be located. This change to the original proposal was made to help
clarify that these standards under UMTRCA complement, and do not
overlap with, the requirements of the SDWA. As discussed in section
I.B., the scope and level of protection of the SDWA differs from the
UMTRCA as groundwater at uranium ISR sites could have beneficial uses
even if the aquifer has been exempted from protection under the SDWA.
Since UMTRCA provides authority that can be used to protect aquifers
during and after uranium recovery operations, regardless of whether the
aquifer meets the definition of an USDW as defined in EPA's UIC
regulations or is exempted from the protections of the SDWA, the scope
of UMTRCA's protection should be reflected in the regulatory text of
these standards rather than relying on the SDWA UIC exemption
regulations. Thus, the regulatory text proposed in this action does not
depend on or use the term exempt aquifer. Also, although a remote
possibility, because ISR facilities may be located in aquifers that are
not designated as ``exempted aquifers'' under the SDWA, under the
original proposal there would have been a lack of clarity on how a
facility located in a non-exempt aquifer would comply with a rule using
``exempt aquifer'' boundaries in the regulatory text.
    Aquifer Exemptions at ISR facilities. The EPA recognizes that
almost all ISR facilities may be considering Class III injection into a
formation that meets the UIC regulatory definition of a USDW and is
afforded SDWA protection. In such scenarios, in addition to applying
for a Class III permit, a Class III owner or operator must (1) apply to
the appropriate UIC Program for an aquifer exemption pursuant to
requirements at 40 CFR 144.7 and 146.4 (or applicable state
requirements), or (2) ensure that the boundaries of an existing
exemption are appropriately delineated for the proposed injection
activity. While aquifer exemptions facilitate commercial production of
minerals and hydrocarbons under specific conditions, the UIC Program
requirements are intended to ensure protection of non-exempted portions
of a formation which meet the definition of a USDW even where ACLs may
be established at an ISR site located within an exempted portion of
that aquifer.
    As stated above, this proposed rule is established under the UMTRCA
and not under the SDWA; however, both the UMTRCA and the SDWA
requirements may apply to ISR facilities. As discussed above and in
section I.A., the requirements of these statutes are complementary and
not overlapping or duplicative. The SDWA requirements provide for
permits to inject lixiviant and recover uranium and possible exemption
of the production zone from SDWA requirements. The proposed UMTRCA
requirements protect adjacent aquifers that are not exempt from SDWA by
requiring monitoring and corrective action, if necessary, during the
operational and restoration phases in and around the ore zone after
production ceases. The SDWA does not prevent recovery and use of the
water within exempted aquifers (including where ISR operations were
previously conducted) for private drinking water supply, public water
supply, or other uses.
2. Changes to the Definition of ``Point(s) of Exposure''
    Points of exposure are defined in the proposal as locations
identified by the regulatory agency that represent possible future
areas of exposure where the receptor can come into contact with
groundwater (e.g., areas of recoverable groundwater). The groundwater
at the point of exposure should be protective of the receptor. As noted
earlier in this preamble, commenters, including interagency commenters,
raised questions concerning the integration of an aquifer exemption
under the SDWA and point of exposure as it was defined in the EPA's
original proposal and the differing jurisdictions of the SDWA and
UMTRCA. The EPA specifically requests comment on this approach,
especially with regard to the overall regulatory model of how ACL
application would work, the definition of points of exposure and the
use of this term, and the overall environmental, human health and
safety protection goals for setting and using ACLs.

E. Excursions

    In the original proposal, the EPA defined an excursion as ``the
movement of fluids containing uranium byproduct materials from an ISR
production zone into surrounding groundwater'' and specified that an
excursion has occurred when ``. . . any two indicator parameters . . .
exceed their respective upper control limits'' (see 80 FR 4184).
1. Changes to the Definition
    Although the EPA generally considers that an excursion has occurred
when any two parameters are above the UCL, in this proposal, the EPA
provides flexibility for the regulatory agency to determine that an
excursion has occurred when any single indicator parameter
significantly exceeds its UCL. The EPA made this change to the proposed
definition because in some situations a single parameter may be
sufficiently high to indicate a possible excursion. The EPA emphasizes
that this would be a judgement of the regulatory agency, and the
Agency's understanding is that it is consistent with current NRC
practice.
    In this proposal, the EPA also revised the definition of excursion
to indicate that an excursion includes the movement of fluids
containing lixiviant, as well as any fluids containing uranium
byproduct material, because these fluids may migrate outside of the ISR
production zone. The EPA replaced the reference to ``the ISR production
zone'' with ``ISR wellfield'' to indicate a broader scope of
consideration is necessary in order to ensure that background is
appropriately addressed and to ensure that areas within and surrounding
the production zone are stable.
2. Changes to the Constituents Required To Be Monitored During the
Different Phases of Operation
    The EPA originally proposed that licensees would be required to
monitor for all constituents listed in Table 1 of 40 CFR part 192,
subpart F, during the different phases of operation at an ISR facility.
In this proposal, the EPA changed this requirement such that facilities
would be required only to monitor for those constituents that are
expected to be present (e.g., uranium, radium, selenium and arsenic)
based on the preoperational monitoring and any other constituents
identified by the regulatory agency. The EPA made this change to the
monitoring parameters to ensure monitoring requirements are established
based on data indicating the expected contaminants. This change reduces
the monitoring burden for ISR facilities compared to the original
proposal. This proposed change also provides the regulatory agency
flexibility to specify any other constituents not listed in Table 1 of
40

CFR part 192, subpart F, that are expected to be present. Under this
proposal, the EPA considers it unnecessary to monitor for constituents
that are not present. Hence, facilities would be required to monitor
only for those constituents that are likely to be present.

F. Initial and Long-Term Stability

    After restoration ends, ISR facilities must demonstrate compliance
with the proposed constituent concentration standards, and also
demonstrate those levels will persist and remain stable in the future.
In the original proposal, to demonstrate stability, the EPA proposed
three consecutive years of stability monitoring with stability
demonstrated at the 95 percent confidence level followed by long-term
monitoring for an additional period of 30-years. The originally
proposed long-term stability monitoring would have allowed facilities
to cease monitoring once they had completed monitoring for 30 years.
However, the original proposal also allowed a licensee to shorten the
30-year long-term stability monitoring period by demonstrating
geochemical stability through monitoring and geochemical modeling.
1. Statutory Authority and 30-Year Long-Term Monitoring
    The EPA derived the 30-year long-term stability monitoring period
in the original proposal based on consideration of the Agency's
statutory mandate to be consistent with the requirements applied to
managing hazardous waste under RCRA.
    Numerous commenters thought the proposed 30 years of long-term
monitoring was not justified, and was excessive and unnecessary. The
general positions of these commenters were that these very specific
monitoring time frames were outside the EPA's statutory authority under
the UMTRCA to promulgate ``standards of general application'' and that
there is no evidence that ISR facilities have impacted offsite
underground sources of drinking water. Commenters also thought the
requirement would have a significant economic impact, including impacts
on leasing and surety costs that would place a number of ISR companies
out of business. Other commenters noted that ISR facilities are not
equivalent to RCRA hazardous waste facilities and should not be
similarly regulated. Some commenters were concerned the long-term
monitoring requirements would increase radiologic dose to employees
maintaining the processing plant and well fields, which would be
inconsistent with the NRC's ALARA (As Low As Reasonably Achievable)
regulations found in 10 CFR part 20. However, other commenters strongly
supported the 30-year monitoring time frame or recommended a longer
time frame. These commenters felt that 30 or more years of monitoring
would provide sufficient time to detect instability and potential
migration of constituents.
2. Proposed Requirements for Initial and Long-Term Stability
    Under UMTRCA, the EPA has authority to promulgate ``standards of
general application'' for the protection of public health, safety and
the environment from the radiological and non-radiological hazards
associated with the processing and the possession, transfer and
disposal of byproduct material at uranium ISR facilities. 42 U.S.C.
2022(b). The Tenth Circuit Court of Appeals has clearly recognized that
this authority encompasses the ability for the EPA to include
monitoring as part of its ``standards of general application.''
American Mining Congress et al. v. Thomas, 772 F.2d 640, 644, 647-649
(10th Cir. 1985) (``The regulations necessitate monitoring programs.''
). In the proposal, the EPA has retained the initial and long-term
stability monitoring requirements but has removed the default
requirement for 30 years of long-term monitoring. The initial stability
monitoring period remains the same as in the original proposed rule
(i.e., at least three years). Under this proposal, the duration of the
long-term stability monitoring must be at least three years, and the
regulatory agency would determine the appropriate length of any
additional long-term stability monitoring based on criteria that will
enable the licensee to demonstrate, as appropriate, that there is
reasonable assurance that the applicable constituent concentration
standards will continue to be met in the future. Similar performance
criteria were part of the standards in the original proposed rule,
where the EPA had proposed that licensees would be required to
demonstrate three consecutive years of initial stability monitoring and
then maintain long-term stability monitoring for an additional period
of 30 years. The original proposal included an option that allowed a
licensee to shorten the 30-year timeframe by demonstrating long-term
geochemical stability through modeling. Under this proposal, modeling
would no longer be optional. Consistent with the original proposal, the
EPA is proposing that the regulatory agency would be responsible for
reviewing the licensee's data and analysis, and making the
determination of when the licensee could discontinue long-term
stability monitoring and initiate decommissioning.
    While many commenters supported the 30-year monitoring requirement,
and some even preferred a longer period, the proposal maintains the
same performance-based standards for the long-term stability phase as
the original proposal and hence ensures the same level of protection
the EPA anticipated in the original proposal. The Agency emphasizes the
role of modeling in achieving that objective. As explained in the
original proposal, the Agency expected that licensees would make
extensive efforts to develop robust models that would significantly
shorten the long-term monitoring period. In fact, as presented in the
proposal, it would have been possible for a licensee to submit modeling
such that no (or minimal) long-term monitoring would be necessary.
However, should licensees be unable to provide such modeling, or choose
not to, the additional monitoring would have provided the level of
confidence necessary for the regulatory agency to determine that long-
term stability had been demonstrated. This revised proposal relies on
modeling and analysis to as an essential element in concluding that
groundwater will continue to meet the applicable constituent
concentration standards into the foreseeable future, leading to the
Agency's judgment that the revised approach is comparable in
protectiveness to the original proposal.
    As noted above, other commenters stated that 30 years of monitoring
would not add value and would put many companies out of business. ISR
facilities that disturb groundwater and mobilize constituents of
concern are responsible for restoring disturbed groundwater to
background or health-based conditions regardless of the time required
to achieve this goal. However, the EPA also agrees with commenters who
noted the time period necessary to establish stability at an ISR
facility is variable due to differences in geology, hydrology and
geochemistry. As reflected by one of the commenters, after 10 years of
monitoring at the Kingsville Dome ISR facility, it appears that
reducing conditions have not been re-established in the production
zone. Restoration at Christensen Ranch has not been approved by the NRC
because the NRC found that restoration was not complete and water
quality was not stable after completion of uranium recovery in
2005.\15\ Uranium concentrations also

increased in a production monitoring well at Smith Highlands Ranch
after restoration was completed.
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    \15\ NRC (2012), ``Technical Evaluation Report: Christensen
Ranch Mine Units 2 through 6 Restoration Report, Uranium One USA,
Inc. Willow Creek ISR Project.'' Available at http://www.nrc.gov/docs/ML1217/ML12174A048.pdf.
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    This proposal defines the initial stability standards as ``three
consecutive years of quarterly monitoring results with no statistically
significant increasing trends exceeding the constituent concentration
standards at the 95 percent confidence level.'' These performance-based
standards would apply after the licensee completes restoration and,
once met, would demonstrate that restoration was initially successful.
The EPA requests comment on this approach and the wording of the
regulatory text. Alternative language the EPA considered for this
proposal for both initial and long term stability, included requiring
the licensee to show `` . . . three consecutive years of quarterly
monitoring results demonstrating a statistically significant non-
increasing trend at the 95 percent confidence level remaining below
each constituent concentration standard.'' This alternative approach,
which would require the licensee to demonstrate that the trend line is
either horizontal or decreasing (``non-increasing''), has been applied
in the Superfund program. It has the clear advantage of accepting only
trend lines that are not increasing, which can provide some additional
confidence that the trend is not in a direction that could (eventually)
threaten to exceed the constituent concentration standards.
    However, based on discussions with the NRC, the agency responsible
for implementing this rule after promulgation, it is clear that
licensees may see increasing, but not statistically significant trends
in constituent concentrations during stability monitoring.
Consequently, the EPA opted to change the language to ``no
statistically significant increasing trend'' to provide the NRC
flexibility in addressing this specific scenario. Further, the EPA is
concerned that specifying a non-increasing trend may introduce
complications in applying statistical techniques, particularly when
working from the hypothesis that there is no slope to the trend line.
The level of natural variation present may itself forestall the ability
to determine a non-increasing slope with the level of confidence the
EPA believes necessary. The level of statistical significance
associated with an increasing trend that would be unacceptable is left
to the regulatory agency to determine based on site-specific
conditions.
    The EPA requests public comment on the proposed approach as well as
the alternatives. Specifically, the EPA would like to know whether this
language is sufficiently protective and whether there are any other
practical approaches the Agency should consider as possible
alternatives.
    In this proposal, the EPA has defined the long-term stability
standards as a two-part test, with the following elements: (1) The
licensee must provide an additional three consecutive years of
quarterly monitoring data demonstrating no statistically significant
increasing trend exceeding the constituent concentration standard for
each applicable constituent at the 95 percent confidence level; and (2)
the licensee must provide geochemical modeling and other analysis to
demonstrate that constituent concentrations within the production zone
will be met in the future. The regulatory agency would evaluate the
modeling and other analysis and make a determination as to whether
there is reasonable assurance that the applicable constituent
concentration standards will continue to be met in the future. In this
proposal, only after this determination has been made by the regulatory
agency would the licensee cease long-term monitoring.
    The three-year long-term monitoring period represents a different
application of the RCRA paradigm than the 30-year post-closure
monitoring. The three-year monitoring period is consistent with RCRA
corrective action requirements, which can be seen as analogous with
groundwater restoration at ISR sites. The Agency believes the three-
year performance standard for the long term is appropriate to provide
additional confidence in restoration of these sites and provides
sufficient time to conduct a trend analysis, as well as being
consistent with RCRA requirements of three years of monitoring to
demonstrate no exceedance associated with corrective action. The EPA
finds that this alternative approach will provide the necessary
protectiveness and is particularly responsive to industry comments
regarding the potential costs associated with a 30-year monitoring
period.

G. Corrective Action Program

    The EPA originally proposed that facilities be required to take
corrective action as soon as practicable but no later than 90 days
after an excursion or exceedance is detected. The original proposal
also required that the concentrations of constituents be returned to
the constituent concentration standards ``within the production zone
and the maximum constituent level in adjacent aquifers'' (see Sec.
192.54(a) of the proposed rule). Groundwater monitoring for a period of
at least three years after corrective action had been terminated was
proposed with reference to the proposed monitoring requirements for the
initial and long-term stability phases.
    A few commenters supported the requirement to take corrective
action as soon as practicable. However, most commenters disagreed with
the original proposed requirement to require ISR facilities to
implement a corrective action program within 90 days. One commenter was
concerned the compliance costs would be high because the wellfield and
associated equipment would have to be maintained at the ISR facility
for many years in order for corrective action to be started within the
required 90 days. Another commenter thought a longer time period was
justified due to the low velocity of groundwater at ISR facilities.
This commenter asserted that additional time may be needed for drilling
wells and installing pump and treat equipment, particularly during the
long-term stability period when equipment has been removed. This
commenter recommended a period of two years be allowed for implementing
a corrective action program and stated that groundwater may move only
10 to 20 feet over this time period. Another commenter noted that the
NRC already has regulations covering corrective action in 10 CFR part
40, Appendix A, Criterion 5D, which specify that a licensee has up to
18 months to implement a corrective action program. One commenter found
the proposed requirements for groundwater monitoring confusing and
questioned why the proposed rule referenced the initial and long-term
stability monitoring requirements. This commenter thought the
groundwater monitoring applied to excursions and questioned why
additional monitoring was necessary for excursions occurring during the
operational phase.
    The EPA has made several changes to the corrective action
requirements in this proposal. First, the EPA would require ISR
facilities to begin (but not necessarily complete) corrective action no
later than 60 days after an excursion or exceedance is detected. The
EPA made this change to be consistent with the NRC's current practice
for excursions.\16\ Full implementation may

take additional time, as recognized by the NRC in 10 CFR Appendix A,
Criterion 5D. The time for the initiation and completion of the
corrective action in all phases of operation would be addressed in the
corrective action program and approved by the regulatory agency.
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    \16\ NRC (2003), ``Standard Review Plan for In-Situ Leach
Uranium Extraction License Applications (NUREG-1569).'' Available at
http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1569/.
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    Second, the EPA is acknowledging that corrective action in the
initial stability phase may be different than in the long-term
stability phase, as during the initial stability phase data are being
collected to show the initial trend and may be more subject to
fluctuation. One exceedance may be acceptable during the initial
stability phase, but not for the long-term stability phase, without
taking corrective action. The EPA is proposing the regulatory agency
would have the authority to determine whether an exceedance truly
warrants action or continued monitoring while the licensee is trying to
establish the data trend during the initial stability phase. The need
for action or monitoring during each phase of operation would be
anticipated and addressed in the corrective action program. Whether or
not the regulatory agency has determined that corrective action is
necessary does not negate or affect the proposed initial stability
standards requiring three consecutive years of quarterly monitoring
results with no statistically significant increasing trends exceeding
the constituent concentration standards at the 95 percent confidence
level. The corrective action program would have to return the
constituent concentrations to levels below the constituent
concentration standards established by the regulatory agency.
    Finally, the EPA is proposing to change the groundwater monitoring
provisions proposed for Sec.  192.54(c) (80 FR 4187) to better reflect
the requirements applicable to ISR facilities that experience
exceedances of constituent concentration standards during the long-term
stability phase. The EPA agrees with a commenter who stated that the
proposed rule language for the groundwater monitoring requirements in
Sec.  192.54(c) could easily be misinterpreted. The change to the
original proposed rule makes it explicit that corrective action is
followed by another round of initial stability monitoring followed by
long-term stability monitoring. Under this proposal, the ISR facility
would need to first meet the three-year initial stability standards,
and then meet the long-term stability standards of Sec.
192.53(c)(3)(i) and (ii), before it is eligible to apply to the
regulatory agency for approval to cease long-term stability monitoring.
These changes to Sec.  192.54(c) would not add any new requirements but
simply clarify the requirements that were originally proposed.

H. Costs and Economic Impacts

1. Compliance Costs
    Commenters expressed concern that the EPA had not considered the
entire spectrum of legal, regulatory and other costs required to hold
and preserve the ISR facility, lands and wellfields during the
stability monitoring periods. The EPA reviewed and updated the economic
analysis to incorporate estimated non-monitoring costs (e.g.,
licensing, leasing fees, continued surety, maintenance) identified in
the comments. Commenters also recommended that the EPA consult the ISR
industry to better characterize costs, and the EPA requested additional
information from some of the uranium recovery companies that had
provided cost data during the public comment period to clarify the
information provided. The additional cost information received from the
uranium recovery companies was incorporated into the economic analysis.
A listing of the non-monitoring costs that were identified in the
comments and added to the revised analysis, along with a comparison of
non-monitoring costs provided by industry and the average values used
in the economic model, can be found in the economic analysis report
(see sections 3.2 and 3.3). The addition of non-monitoring costs added
$2,300 per acre to the modeled average facility costs excluding license
and surety. The estimated total annualized incremental non-monitoring
costs projected to be incurred by firms owning existing ISR facilities
ranged between $0.1 million and $4.1 million, with total national non-
monitoring costs of $7.6 million for all firms. All costs in the
economic analysis have been adjusted from 2011 to 2015 dollars, as
suggested by commenters.
    Another concern expressed by commenters was that the EPA had not
considered additional costs to self-funded regulatory programs, and
that these costs would be passed along to the uranium recovery
companies. The revised standards reflect the practices that have become
more common between the NRC and ISR facilities; therefore, this
proposal is not expected to add significant burden to regulatory
programs.
    Compliance for existing ISR facilities also concerned commenters.
As in the proposal, Sec.  192.52(a) of this proposal makes clear that
these standards would not apply to wellfields that are currently in and
remaining in restoration or stability monitoring.
    Commenters also expressed concern that the costs of monitoring were
not adequately reflected due to inaccurate assumptions for current
monitoring requirements. The EPA adjusted the monitoring costs in the
economic analysis based on guidance received from the NRC regarding
current monitoring practices and requirements, as opposed to historical
practices that were noted by some commenters as common to more
developed ISR facilities. Also, a commenter noted that the rule
discussion in the proposal preamble at 80 CFR 4186 (Sec.  192.53(a)(3)
of the original proposal) required monitoring well locations outside of
the monitoring well ring and that these costs were not included in the
economic analysis. The proposal maintains the requirement in the
original proposal for down-gradient monitoring wells outside the
monitoring well ring where needed, and at the discretion of the
regulating agency, especially when an adjacent aquifer is present.
Initially, the EPA's proposal required monitoring at locations down-
gradient from the wellfield in exempted aquifers. However, placement of
down-gradient monitoring wells outside the well ring was not found to
be common practice at existing sites and the EPA removed these wells
from the cost model. The EPA also assumed in the proposal that