
[Federal Register Volume 82, Number 12 (Thursday, January 19, 2017)]
[Proposed Rules]
[Pages 7400-7430]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-00573]



[[Page 7399]]

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  

[[Page 7400]]


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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: a-and-r-docket@epa.gov.
     Fax: (202) 566-9744.
     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 (202) 566-1744, and the 
telephone number for the Air and Radiation Docket is (202) 566-1742.

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: (202) 343-9286; fax 
number: (202) 343-2304; email address: Rosencrantz.ingrid@epa.gov.

SUPPLEMENTARY INFORMATION: 

A. Does this action apply to me?

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

[[Page 7401]]



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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 (202) 343-9597. 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

[[Page 7402]]

    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

[[Page 7403]]

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

[[Page 7404]]

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

[[Page 7405]]

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.
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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

[[Page 7406]]

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.
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    \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

[[Page 7407]]

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

[[Page 7408]]

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).

[[Page 7409]]

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

[[Page 7410]]

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''.

[[Page 7411]]

 
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

[[Page 7412]]

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;

[[Page 7413]]

    (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

[[Page 7414]]

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

[[Page 7415]]

increased in a production monitoring well at Smith Highlands Ranch 
after restoration was completed.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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

[[Page 7416]]

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.
---------------------------------------------------------------------------

    \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/.
---------------------------------------------------------------------------

    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 
monitoring and hydrogeologic and geochemical modeling requirements 
would allow most sites to demonstrate that groundwater conditions down-
gradient of the wellfield would trap any mobilized constituents, thus 
ensuring that groundwater quality is protected. Reference to the 
``exempted aquifer'' has also been removed from this proposal, as 
discussed in section III.D of this preamble.
    Comments were also received on the methodology used to extrapolate 
a cost per acre for operating ISR facilities based on a conceptual ISR 
unit, and while it was acknowledged that the method may be appropriate 
for fully developed ISR facilities, the commenters were concerned that 
this methodology may not capture the full costs of implementation for 
facilities in earlier stages of development. The EPA further reviewed 
and used available information from facility surety and license reports 
to estimate and account for the proposed and anticipated number of ISR 
units at each ISR facility that was included in the cost model.
    In light of the adjustments described above, the EPA considers the 
estimated

[[Page 7417]]

monitoring costs for existing ISR facilities that it developed for 
purposes of the proposal to be reasonable; however, the Agency 
continues to recognize that there are uncertainties inherent to the 
process used to extrapolate the monitoring costs associated with these 
standards as compared to actual costs to ISR facilities.
2. Energy Impacts Summary
    Several commenters noted the importance of nuclear power to shift 
the nation's reliance away from carbon-based energy resources and 
expressed concern that the proposed standards would reduce the 
viability of uranium recovery and continued development of nuclear 
energy. In response to these comments, the EPA reevaluated the 
incremental costs of the selected option to existing and planned ISR 
facilities, which further substantiated that this action is not a 
``significant energy action'' as defined in Executive Order 13211 (66 
FR 28355, May 22, 2001). The proposed standards, in large part, codify 
groundwater monitoring practices and requirements already being 
implemented at permitted operations; further, domestic uranium has 
historically provided less than 10 percent of total uranium supplied to 
civilian owners and operators (COOs) of nuclear power stations. Because 
the proposal would increase the costs of facilities that produce a 
relatively small share of uranium traded in U.S. markets, the EPA 
estimate that a $1.96 increase per pound in the cost of ISR uranium 
production would increase the price of uranium paid by COOs by only 
$0.11 per pound. Because nuclear generation provides a relatively small 
share of total domestic electricity, the $0.11 increase in the price of 
uranium would increase the price of electricity very little (less than 
0.1 percent). Although the proposal would slightly increase the costs 
of domestic uranium production relative to international sources, this 
rule is not expected to directly and adversely affect productivity, 
competition or prices in the energy sector. For more information, 
please see section VI.H of this preamble and sections 5.3 and 6.9 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.
3. Groundwater Resource Impacts of Restoration
    Several commenters expressed concern that the proposed rule would 
cause an unnecessary waste of groundwater resources beyond diminishing 
returns, due to prolonged additional restoration to satisfy the 
proposed requirement for 95 percent statistical confidence of 
groundwater stability. The EPA disagrees and believes that the 95 
percent statistical confidence level is widely accepted and used in 
other environmental standards. For more information on the 95 percent 
confidence level, see section IV.D of the preamble.
    One commenter stated that the EPA ignored its authority under 
CERCLA that allows the Agency to require former operators and their 
successors to clean up post-license termination, thereby unnecessarily 
increasing monitoring costs for ISR facilities. The EPA does not 
believe it is appropriate to rely upon expectations of future cleanup 
rather than make reasonable efforts to prevent groundwater 
contamination in the first place. The intent of this rule is to protect 
groundwater and prevent its degradation, thereby eliminating the need 
for remedial actions under CERCLA that, by the time discovered, could 
be far costlier. This approach is fully consistent with the EPA's 
Groundwater Protection Strategy, which emphasizes pollution prevention 
over remediation. Also, commenters asserted that the groundwater 
modeling was inadequate, and flawed inputs were used to estimate the 
duration of remediation to clean up a plume after facility closure. The 
EPA understands that the contaminant transport models used to estimate 
costs of remediating a contaminant plume are simplistic, the inputs 
used are based on limited ISR facility data, and selected 
parameterizations are based on assumptions. Nevertheless, the flow 
model provides a reasonable estimate for the duration of an 
illustrative general pump and treat remediation scenario, based on the 
EPA's extensive pump and treat remediation experience under CERCLA and 
other remedial programs, and, upon review, the models and inputs were 
determined to be adequate to illustrate potential cost savings for 
purposes of the economic analysis.

I. Other Miscellaneous Changes

1. Clarification of ``Operational Phase''
    In the original proposal, the EPA defined the operational phase of 
an ISR facility as ``the time period during which uranium extraction by 
in-situ recovery occurs'' and noted that ``operations end when the 
operator permanently ceases injection of lixiviant and recovery of 
uranium-bearing solution for processing'' (see 80 FR 4160). However, 
the EPA notes there are periods when the ISR facility is not actively 
recovering uranium for various reasons (e.g., market conditions), but 
production is intended to resume when conditions are more favorable. 
These periods are sometimes referred to as ``standby'' by operators. In 
the original proposal, the EPA expressed the view that it would not be 
appropriate to allow a standby period for ISR facilities if the 
gradient within the wellfield is not being maintained, and that 
stopping the extraction cycle should require the operator to enter the 
restoration phase. Commenters acknowledged that ISR facilities can 
experience extended periods of standby and noted that active pumping 
during these periods is necessary to prevent contamination of 
groundwater in areas outside the production zone. One commenter 
recommended the EPA minimize the amount of time during which an ISR 
facility in standby is not pumping. Other commenters thought ISR 
facilities entering standby should be required to initiate restoration 
and recommended that the EPA require ISR facilities to commence 
restoration within a specified time period after ceasing active uranium 
recovery.
    The EPA agrees with the commenters who said ISR facilities must be 
responsible for ensuring that lixiviant and constituents do not migrate 
outside of the production zone during standby periods. The EPA 
disagrees with the commenter who suggested ISR facilities that 
temporarily cease operations should be required to commence 
restoration. The EPA agrees, however, that during standby periods the 
migration of constituents mobilized by the prior injection of lixiviant 
may continue even if the decision is made to stop extracting uranium. 
Excursions beyond the production zone are more likely to occur if the 
hydraulic gradient within the wellfield is not maintained. For this 
reason, the EPA considers standby to be part of the operational phase, 
and facilities should not cease pumping during standby periods since it 
is important that an inward hydraulic gradient is maintained during 
these periods. For this reason, the EPA is proposing that all 
requirements applicable to the operational phase remain in effect 
during these standby periods. Provided the licensee complies with the 
operational phase monitoring and corrective action requirements in the 
proposed rule, ISR facilities in standby would not need to enter 
restoration because groundwater in areas surrounding the production 
zone will be afforded the same level of

[[Page 7418]]

protection as required during restoration. In this proposal, the EPA 
has revised the definition of ``operational phase'' in original 
proposal to clarify that standby mode is considered part of the 
operational phase and that ISR facilities in standby must maintain 
appropriate groundwater controls to prevent constituents from leaving 
the production zone.
2. Changes to the Definition of ``Point(s) of Compliance''
    As stated in the original proposal, during the restoration phase, 
the definition of ``point(s) of compliance'' may include ``monitoring, 
injection, and extraction wells in the production zone'' (see 80 FR 
4184). Points of compliance during the initial stability and long-term 
stability phases should include locations within the former production 
zone, including existing monitoring, injection and extraction wells. To 
clarify these requirements, in this proposal, the EPA revised the 
definition of ``point(s) of compliance'' to indicate that excursion 
monitoring wells are considered points of compliance during all phases 
of ISR operation and that during the initial and long-term stability 
monitoring phases, points of compliance should also include locations, 
identified by the regulatory agency, where a potential receptor can 
come into contact with contaminated groundwater. The EPA is 
specifically requesting comment on the definition of ``point(s) of 
compliance'' and how it is applied. Again, the EPA is requesting 
comment on the definition of point of exposure and conceptual framework 
for establishing ACLs.

IV. Responses to Other Significant Comments That Did Not Result in 
Changes to the Original Proposal

    The EPA carefully reviewed and considered comments from a wide 
range of different groups in preparing this proposal. As discussed in 
section III of this preamble, the EPA modified and clarified various 
aspects of the proposed rule based on the information and views 
provided, including comments on the original proposal. However, not all 
comments resulted in modifications to the proposed rule. Those 
significant comments that did not result in changes, together with the 
EPA's responses, are summarized in this section of the preamble.

A. Authority To Set Generally Applicable Standards

    Some commenters thought the proposed rules were legally invalid and 
felt the EPA was overreaching its authority under UMTRCA by proposing 
standards that are too detailed and prescriptive. The commenters argued 
the EPA was redefining what UMTRCA established as the EPA's role to set 
general standards while making the NRC responsible for implementing 
those standards through its licensing process. These commenters believe 
that UMTRCA limits the EPA's authority to setting general standards 
that do not include any prescriptive implementation requirements. Some 
of these commenters cited a statement from the legislative history of 
UMTRCA in which a House Committee advised that ``[t]he EPA standards 
and criteria should not interject any detailed or site-specific 
requirements for management, technology, or engineering methods on 
licensees or the Department of Energy.''
    However, other commenters thought the proposal was an appropriate 
exercise of the EPA's authority under the UMTRCA because the proposed 
rule would not supplant the NRC's jurisdiction or impede its licensing 
authority. They cited the statutory provisions that assign the 
authority to set standards to the EPA and the authority to implement 
and enforce the standards to the NRC (See 42 U.S.C. 2022(b), (d)). The 
commenters thought the proposed standards were an appropriate 
application of the EPA's authority under the UMTRCA and felt that the 
EPA had correctly left implementation of the new standards to the NRC 
and Agreement States.
    The Agency disagrees with those commenters who believe the EPA has 
redefined its role or overreached its authority in developing the new 
standards for ISR facilities. Section 206 of the UMTRCA clearly 
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 the 
processing and the possession, transfer and disposal of byproduct 
material at uranium ISR facilities. See 42 U.S.C. 2022(b). The Tenth 
Circuit Court of Appeals affirmed EPA's authority to set such standards 
under UMTRCA in two companion cases challenging the original part 192 
rules. See American Mining Congress et al. v. Thomas, 772 F.2d 617 
(10th Cir. 1985) (``AMC I''); American Mining Congress e. al. v. 
Thomas, 772 F.2d 640 (10th Cir. 1985) (``AMC II''). Consistent with the 
reasoning of these opinions, the new standards proposed in this action 
would apply the same requirements to all ISR facilities and would 
establish general requirements to (1) meet constituent concentration 
standards and demonstrate groundwater conditions are stable with 95 
percent confidence; (2) conduct monitoring; and (3) develop and 
implement a corrective action program. Within the framework of these 
generally applicable standards, the regulatory agency would be 
responsible for implementing the proposed new standards on a site-
specific basis through the licensing process and would retain the 
authority to determine when an ISR license can be terminated. AMC II, 
772 F.2d at 647-648 (``General application standards that allow the 
Nuclear Regulatory Commission (NRC) to choose the means of 
implementation are consistent with the authority Congress vested in the 
EPA.'').
    The first of these three components of the proposed standards has 
two integral parts--numerical constituent concentration standards and 
groundwater stability standards. This proposal sets forth minimum 
requirements for the constituent concentration standards, but 
implementation of those standards on a site-specific basis remains the 
responsibility of the regulatory agency. However, a numerical 
concentration standard by itself is not sufficient to address ``the 
risk to public health, safety, and the environment'' that the EPA is 
required by statute to consider when setting general standards. 42 
U.S.C. 2022(b)(1). Since ISR facilities alter the natural groundwater 
flow, this risk includes the risk that constituent concentrations in 
the groundwater will not remain the same over time if the groundwater 
remains unstable. Thus, to address this risk, the proposed rule 
contains a general requirement to demonstrate that groundwater 
conditions are stable after production ends at a site. For example, to 
satisfy the proposed initial stability standards, ISR facilities would 
provide three consecutive years of quarterly monitoring results 
demonstrating no statistically significant increasing trends exceeding 
the constituent concentration standards at the 95 percent confidence 
level. This proposed requirement to demonstrate groundwater stability 
is an integral part of the standard. The proposed general standard for 
stability is defined by a level of statistical confidence that is 
applicable to all sites. EPA believes this level of statistical 
confidence is necessary at all sites to ensure that the stability 
standards are sufficiently stringent to address the risk that 
groundwater exceeding the applicable constituent concentration 
standards poses to public health, safety and the environment from ISR 
facilities that have ceased operation. Contrary to some commenters' 
remarks (see Section

[[Page 7419]]

IV.D below), the proposal does not include any ``detailed or site-
specific requirements'' regarding how an ISR facility must satisfy the 
95 percent confidence level. Hence, these proposed standards lack any 
``management, technology or engineering methods'' pertaining to this 
confidence level. The proposed stability standards do not prescribe 
what specific statistical methods, sampling methods, or monitoring 
equipment should be used to show 95 percent confidence. Such decisions 
are left to the regulatory agency through its licensing of each 
facility. The Tenth Circuit has recognized that other provisions with 
these characteristics are within EPA's standard-setting authority under 
UMTRCA. AMC I, 772 F.2d at 630 (``Furthermore, because the standards 
are general in nature--they apply to all sites--we do not view them as 
site-specific `management, technology or engineering methods.' ''); AMC 
II, 772 F.2d at 645-646 (``Most of the arguments by the various 
petitioners are substantially identical to those in the consolidated 
Inactive Sites Case decided this day. On the basis of the analysis in 
that opinion, we again hold . . . that the EPA's standards do not 
unlawfully impose management, design, and engineering require- ments. . 
. .'').
    Some commenters argued the long-term monitoring requirements in the 
original proposal were too prescriptive and that the EPA would be 
effectively dictating when a license could be terminated. As noted 
above, the Tenth Circuit has clearly recognized that the EPA's 
standard-setting authority under UMTRCA enables the EPA to include 
monitoring as part of its ``standards of general application.'' AMC II, 
772 F.2d at 644 (``The regulations necessitate monitoring programs.''). 
In affirming the monitoring provisions in the original part 192 rule 
(monitoring provisions that are very similar to those in this 
proposal), the Court in AMC II readily distinguished between monitoring 
that is properly included as part of a standard the EPA promulgates and 
more prescriptive monitoring requirements that should be left to the 
regulatory agency. AMC II, 772 F.2d at 647-648 (``The regulations 
require the industry to satisfy SWDA drinking water concentration 
standards at specified distances from the pile, but they do not dictate 
the kind of monitoring system that must be used or the method by which 
purity levels must be achieved. These decisions are left to the 
implementing agency, the NRC.''). The EPA has not included detailed 
monitoring requirements in these proposed standards (e.g. what kind of 
monitors to use), but has instead left those details up to the review 
and approval of the NRC or the Agreement State.
    Several comments were also critical of the EPA's authority to 
require corrective action programs. While the term ``standard'' 
includes numerical limitations, such as the concentration-based limits 
for the listed constituents in groundwater, the EPA has long 
interpreted this term to also encompass the actions a source must take 
to reduce, remediate or otherwise avoid release of pollutants. The EPA 
notes that the existing rule, in subpart D, includes similar non-
numerical standards to those included in this proposed rule. For 
example, 40 CFR 192.32(a)(2)(iii) requires affected sources to 
implement detection monitoring programs, while 40 CFR 192.32(a)(3)(i) 
requires uranium mill tailings piles or impoundments to have a 
permanent barrier.
    In sum, the regulatory agency must determine the constituent 
concentration standards applicable to each site, approve the number, 
location, and installation of all wells used for monitoring, and 
determine when the initial and long-term stability standards are 
satisfied. See AMC II, 772 F.2d at 647-648 (Court affirms standards 
because ``they do not dictate the kind of monitoring system that must 
be used or the method by which purity levels must be achieved. These 
decisions are left to the implementing agency, the NRC.'') The 
regulatory agency is also responsible for approving the licensee's 
corrective action program and, when an excursion has occurred, 
determining when corrective action should begin and when it can cease. 
The regulatory agency may also bring enforcement actions against any 
non-compliant ISR facility. Thus, as required by UMTRCA, and consistent 
with the case law affirming the EPA's previous part 192 rulemakings, 
the implementation and enforcement of the proposed new standards remain 
with the regulatory agency.

B. Need for New Standards for Uranium ISR Facilities

    Several commenters concurred with the EPA's assessment that new 
standards are necessary for ISR facilities. These commenters noted that 
environmental impacts from ISR are significantly different from the 
impacts of conventional mining and milling. Commenters supported the 
EPA's conclusion that a more rigorous approach is warranted for 
determining background groundwater concentrations. They considered the 
preoperational monitoring requirements as necessary to establish 
appropriate concentration-based standards for each ISR facility. They 
also supported the stability-phase monitoring, which they considered 
important for demonstrating groundwater stability after restoration and 
for providing assurance groundwater quality will not degrade over time 
and that constituent migration will not occur in the future. One 
commenter felt that more rigorous standards with detailed restoration 
and long-term stability demonstrations were necessary to bring 
``coherency and accountability'' to ISR facilities. However, other 
commenters thought the rule was unnecessary and provided a variety of 
reasons to support their contentions. Most commenters felt the 
standards were not justified because the industry was already 
regulated, arguing that the EPA had failed to provide or quantify 
sufficient evidence that ISR poses a risk, or had failed to consider 
relevant data. A number of commenters asserted that EPA had not 
adequately addressed recommendations of the Agency's SAB. Many 
commenters noted that ISR facilities are already regulated by the EPA, 
the NRC, and states, and that the success of the existing regulatory 
oversight over the last 40 years proved that further regulation was not 
needed. In support of their statements, these commenters stated that 
there were no documented cases of off-site contamination of drinking 
water supplies from ISR activities in the United States. Other 
commenters noted that the new standards were unnecessary because ISR 
facilities are located in exempted aquifers under the SDWA in 40 CFR 
146.4 and cannot serve as sources of drinking water because the EPA has 
already determined the water is unsafe for human consumption. One 
commenter stated that the SDWA UIC program has requirements prohibiting 
injection of fluids where production fluids could migrate into non-
exempt aquifers and stated that these existing requirements were 
sufficient to protect groundwater. Other commenters argued the 
regulations were unnecessary because ISR facilities already collect 
background water quality data, restore groundwater impacted during 
recovery, and monitor for stabilization after restoration under the 
existing regulations. Some commenters felt the migration of uranium 
from ISR facilities was unproven. These commenters cited papers they 
said showed uranium had

[[Page 7420]]

not migrated from ISR facilities.\17\ A few commenters recommended the 
EPA postpone promulgation of the rule until additional research could 
be completed and the health and environmental risks better understood.
---------------------------------------------------------------------------

    \17\ The commenter cited the following two papers: (1) Basu, 
Anirban, et al., ``Isotopic and Geochemical Tracers for 
U(VI)Reduction and U Mobility at an In Situ Recovery U Mine'', 
Environmental Science Technology, April 24, 2015, 49(10), pages 
5939-5947; and (2) Reimus, Paul, ``Field Evaluation of the 
Restorative Capacity of the Aquifer Down Gradient of a Uranium In 
Situ Recovery Mining Site'' presented at the ``2015 In situ Recovery 
of Uranium Research Symposium'' held at the University of Wyoming, 
Laramie, Wyoming, April 21, 2015.
---------------------------------------------------------------------------

    The EPA disagrees with commenters who contend that new standards 
are unnecessary. First, it is in the national interest to protect 
groundwater resources. Water is becoming a scarce resource, 
particularly in the arid regions where most ISR currently operate. 
Groundwater in this region is not exclusively used for human 
consumption, and has other uses such as livestock production, crop 
irrigation, and wildlife support. The best way to preserve groundwater 
for all such uses is to prevent contamination by addressing the source 
of contamination. The SDWA UIC program plays an important role in 
protecting underground sources of drinking water. However, as discussed 
in section I.A. above, the scope and level of protection of the SDWA 
differs from the UMTRCA. 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. UMTRCA provides authority that can be used to 
require restoration of the groundwater in the production zone and to 
protect the groundwater outside the production zone aquifer, during and 
after uranium recovery operations, regardless of whether the aquifer 
has been exempted from the protections of the SDWA.
    Thus, this proposed rule under UMTRCA is needed to establish 
generally-applicable groundwater standards for ISR facility restoration 
and require more extensive monitoring, modeling and analysis to ensure 
that groundwater restoration will endure. ISR alters the chemical 
composition of groundwater and creates reasons to be concerned about 
risk of mobilization of constituents. The EPA notes that several NRC-
regulated sites are continuing to work toward restoring groundwater 
with restoration and monitoring being conducted for as long as 10 years 
after ceasing production.\18\ In addition, restoration does not always 
meet original background levels as evidenced by the number of 
restoration goals above background or Table 1 levels.\19\ In addition, 
the NRC acknowledges that efficiency could be gained by codifying its 
longstanding effective regulatory regime into regulations specific to 
ISRs. As described in the original proposal, this rulemaking was 
initially prompted by the NRC's conclusion that ISR-specific rules are 
needed to create a more workable and sustainable regulatory framework 
for this activity, and is not based on any specific instances of 
identified contamination.\20\ The EPA considers the approach to 
protecting groundwater in this proposal to be reasonable and 
responsible. The EPA further notes that remediation of contaminated 
groundwater is more expensive and difficult to achieve than for surface 
waters because it is not easily accessible. It is more cost-effective 
to prevent contamination by ISR facilities than to clean it up after 
wide-spread contamination occurs.
---------------------------------------------------------------------------

    \18\ EPA (2016), ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites'', 
available in Docket ID No. EPA-HQ-OAR-2012-0788.
    \19\ Ibid.
    \20\ NRC (2006), ``Regulation of Groundwater Protection at In-
Situ Leach Uranium Extraction Facilities,'' COMJSM-06-001, January 
17, 2006; http://www.nrc.gov/reading-rm/doc-collections/commission/comm-secy/2006/2006-0001comjsm.pdf.
---------------------------------------------------------------------------

    Second, the information the EPA has reviewed indicates that current 
industry practices for restoration and monitoring of the affected 
aquifer may not be adequate to prevent degradation of water quality at 
ISR facilities or the more widespread contamination of surrounding 
groundwater that is suitable for human consumption. Historically, once 
restoration is halted, stability demonstrations at ISR facilities are 
typically conducted for only a short period, which may not be adequate 
to determine that restoration is complete and long-term stability 
established. Several instances are noted in section III.F.2 where 
facilities have monitored for lengthy periods after restoration was 
deemed to be complete, but have not been able to demonstrate stability 
for even the more limited times typically required under current 
practice. The initial and long-term stability monitoring and corrective 
action program included in the new proposed rule would provide greater 
confidence that both of these requirements are met before ISR 
facilities can be decommissioned.
    Finally, the EPA considers the existing regulations at 40 CFR part 
192 to be inadequate for addressing groundwater contamination from ISR 
facilities. Subparts A, B and C of 40 CFR part 192 apply to inactive 
uranium milling facilities, vicinity properties, and depository sites 
(i.e., Title I sites). Only subpart D is applicable to active uranium 
processing and disposal sites; however, subpart D primarily targets 
conventional milling as it contains provisions for managing uranium 
byproduct materials during and following the processing of uranium ore 
and for the restoration of disposal sites. Although the standards in 
subpart D applied to ISR facilities, ISR was not the predominant 
uranium extraction method at the time the standards were promulgated. 
ISR differs significantly from conventional mining and milling and 
consequently presents different environmental concerns from those of 
conventional mining and milling operations. For example, ISR does not 
generate large volumes of solid waste materials or require permanent 
tailings impoundments as does conventional mining and milling. 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. The purpose of restoration activities is to 
restore the groundwater to the applicable constituent concentration 
standards. Although 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 subpart F, the operator would be required to 
restore the groundwater in the production zone aquifer 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 that restoration will 
persist in the future.
    Regarding comments that the EPA did not request or collect data 
from industry, the Agency disagrees. The EPA has appropriately 
considered available data to support its proposed rules and requested 
additional data from industry. During the SAB's public teleconferences 
in 2011, industry stakeholders stated that additional data

[[Page 7421]]

was available beyond that contained in EPA's draft report. The EPA 
requested this information from the National Mining Association in 
January 2012; however, the EPA found that the data provided by NMA had 
already been considered by the EPA. The EPA also provided an additional 
60 days for public comment on the original proposal for industry 
stakeholders to provide additional data. While the data did in some 
cases appear to involve longer-term monitoring at some sites, the 
information was largely piecemeal and lacking in context. Consequently, 
the EPA did not find this information useful.
    The EPA further believes the commenters have misinterpreted the SAB 
recommendation to constructing a database to support modeling and build 
an evidence base for EPA's rulemaking. In section 3.2, page 8, the SAB 
discusses the development of such a database. However, in section 3.3, 
the SAB goes on to recommend that ``for the near term, until the needed 
large evidence base is accumulated and systematized, that the EPA 
[should] articulate a set of guiding principles and assumptions on 
which to base regulations. The proposed standards can be based on these 
assumptions during the next several years, and superseded if evidence 
of their unsuitability becomes available.'' (emphases added). The SAB 
clearly did not intend for EPA's rulemaking to be held in abeyance 
until all available data had been collected, systematized, and 
analyzed. Rather, the SAB viewed this as a longer-term effort in which 
EPA's standards could be modified should the underlying assumptions not 
be supported by additional data. Further, because of the limited long-
term data available for sites once they have been deemed ``stable,'' 
which the SAB members recognized during the July 2011 meetings, in 
EPA's view this necessarily involved a period during which EPA's 
standards would be effective and require collection of such longer-term 
data.
    However, as mentioned earlier, given the concern about data 
collection and the comments concerning lack of state data, the EPA will 
consider additional data collection and analysis, including review of 
affected state regulatory programs. The Agency also takes issue with 
some comments characterizing the UIC program requirements. An aquifer 
exemption is not a judgment that the water is unsafe for human 
consumption. In most, if not all, cases, an ISR facility is provided 
with an aquifer exemption solely because of the presence of uranium 
that is economically producible. Further, while the UIC program 
objective is to prevent endangerment of USDWs, it is the responsibility 
of the permittee to operate in a manner that does not allow production 
fluids to migrate into non-exempt aquifers. 40 CFR 144.12(a).

C. Applicability

    Consistent with the original proposal, this proposed rule does not 
apply to licensed ISR facilities that are engaged in restoration, 
initial stability monitoring, or long-term stability monitoring. 
However, some commenters stated that the original proposed rule should 
not apply to existing ISR facilities that are currently operating. 
These commenters noted that it was not clear how an existing ISR 
facility would comply with the proposed rule for ISR wellfields that 
are already in the operational, restoration or stability monitoring 
phase. Commenters stated that preoperational background water quality 
would have already been established for operational wellfields, but the 
methods used to establish the background concentrations may not be 
consistent with the requirements in the proposed rule. They noted that 
it would not be possible to resample for background water quality for 
operating wellfields since the aquifers have already been changed by 
uranium recovery operations.
    The EPA sees no need to omit existing ISR facilities from this rule 
due to preoperational considerations. The NRC already requires ISR 
facilities to establish background conditions prior to beginning 
operation under 10 CFR part 40, Appendix A, Criterion A. Under this NRC 
guideline, an ISR facility must implement a preoperational monitoring 
program that provides complete baseline data on the facility and its 
surrounding area. In addition to the NRC guidelines, ISR facilities 
conduct studies of the ore zone prior to beginning production to 
collect data necessary for designing the ISR facility. Although the 
most appropriate monitoring would consist of a statistically 
representative sample of wells spatially distributed throughout the 
wellfield, the EPA recognizes that operating facilities cannot collect 
unaffected background samples at ISR facilities that are already 
operating. However, facilities that are already operating, but have not 
yet entered the restoration phase, can use the background data they 
collected prior to operation to set their constituent concentration 
standards. Even with limited data, existing ISR facilities can analyze 
the preoperational data they collected and develop a statistically 
meaningful data set to use as the basis for the constituent 
concentration standards and also define other aspects of the system, 
such as the flow regime, that are necessary to develop site models. 
Selecting high or the highest values of the chemical monitoring data 
would not be considered an appropriate basis for establishing 
background conditions. Further the collection of data to demonstrate 
stability would be essentially the same for all facilities.

D. The 95 Percent Confidence Level

    The original proposed rule contained a requirement to gather 
monitoring data sufficient to demonstrate the stability of groundwater 
with 95 percent confidence. Some commenters thought the 95 percent 
confidence level was too restrictive. These commenters stated that the 
EPA did not address properly the cost, both in dollars and water 
resources, required to achieve a 95 percent confidence level. Some of 
these commenters misinterpreted the 95 percent confidence requirement 
as a restoration goal requiring the constituent concentrations to be 
reduced by 95 percent, rather than a level of confidence in the 
statistical tests used to assess stability. Most commenters thought the 
95 percent confidence level was too high, while a few thought it was 
too low. A few comments addressed the general requirements to 
demonstrate that the hydrogeological and geochemical properties have 
been returned to preoperational condition and expressed concern the 95 
percent confidence level would be required for the statistical tests. 
Many of these comments indicated a concern with the high variability of 
these properties at ISR facilities. Concerns were raised that many of 
the ionic species are reported in the parts per billion and parts per 
million concentrations and duplication of analysis on the same sample 
can vary a few parts per million when samples are rerun.
    Some commenters thought that the original proposed rule was not 
sufficiently prescriptive. Several commenters expressed concern with 
the statistical tests recommended for detecting trends and for the 
comparison with baseline values. These commenters noted that important 
details required to implement the statistical tests are not provided in 
the proposed rule, including whether the statistical analysis is 
conducted for the well field as a whole, within clusters or well-by-
well; what parameter should be tested; and what requirements there are 
for the tests, particularly for the trend test.
    This proposal retains a 95 percent confidence level but makes it 
clear that

[[Page 7422]]

this is part of the generally applicable stability standard in both the 
initial and long-term stability phases. The 95 percent confidence level 
is used to define stability, and EPA considers a confidence level a 
measure of stringency of the standard. This is one approach for 
defining stability, but not necessarily the only approach. However, the 
EPA is concerned that a stability standard that lacks any statistical 
criterion would provide insufficient assurances that full restoration 
has been achieved and allow stringency of the standard to vary from 
site-to-site, thus failing to fulfill EPA's obligation to produce 
standards of general application. See AMC I, 772 F.2d at 638-639 
(finding the EPA failed to specify generally applicable standards by 
directing the regulatory agency to determine standards that could vary 
on site-specific basis). The EPA requests comment on alternative 
approaches that would present a rigorous benchmark against which to 
measure and ensure stability.
    The 95 percent confidence criterion would apply for all 
constituents. The proposed standards to demonstrate initial and long-
term stability with 95 percent confidence would be applied after 
restoration has been completed to confirm that the restoration was 
successful and likely to persist. Again, the EPA requests that 
commenters share examples where the 95 percent confidence level cannot 
be used or met and the limitations of these examples and the Agency 
invites commenters to propose other options that would clearly 
represent a valid and explicit groundwater stability standard that 
includes a measure of stringency.
    The EPA understands that NRC staff has attempted to use the 95 
percent confidence level for at least one facility (see the NRC 
presentation in the BID) but has concerns about its use in every case. 
The Agency considered changing the level of confidence, however the 95 
percent confidence level is the standard used under other regulatory 
programs, including the EPA's hazardous waste program. It is a widely 
accepted standard used across many industries that must monitor 
groundwater. Again, the EPA requests comment on the use of the 95 
percent confidence level as part of the stability standard and whether 
there are better or more practical ways to word the standards such that 
they present a clear level of stringency.
    The costs of conducting the statistical tests are related largely 
to the number of wells monitored and the duration and frequency of 
baseline and post-restoration monitoring. These costs are not related 
to the dollar and resource costs of restoration. The EPA recognizes 
there is a trade-off between the cost of additional monitoring and the 
level of confidence achieved in the confirmatory statistical tests. Due 
to the high variability in hydrogeological and geochemical properties 
it may be necessary to do more monitoring to compensate for the higher 
variability.
    While the proposed initial and long-term stability standards define 
stability as attaining 95 percent confidence, the methods to be used to 
demonstrate compliance would be determined by the regulatory agency. 
The BID \21\ provides suggested sampling plans for stability monitoring 
that include instructions for applying the parametric and nonparametric 
statistical tests to detect trends and for comparing with baseline 
values. Each statistical test has its own set of parameters, null and 
alternative hypotheses, decision rules and underlying assumptions about 
the data. However, it was not the intention of the EPA to provide 
detailed instructions for conducting the statistical tests in the rule. 
The licensee would be responsible for selecting the specific 
statistical test to be used for stability monitoring and comparisons 
with the baseline values. EPA expects that the regulatory agency would 
provide additional guidance regarding the statistical analysis required 
and the reasons for using the statistical test, the concepts of Type 1 
and Type 2 errors, the calculations required to perform the test, and 
how test results are interpreted. Information about what parameter is 
tested, the null and alternative hypotheses, requirements for 
implementing the statistical tests and tables for interpreting test 
results is included in the BID. Decisions concerning whether the 
statistical analyses are conducted for the well field as a whole, 
within clusters, or well-by-well would remain a responsibility of the 
regulatory agency.
---------------------------------------------------------------------------

    \21\ EPA (2016), ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites'', 
available in in Docket ID No. EPA-HQ-OAR-2012-0788.
---------------------------------------------------------------------------

V. Summary of Environmental, Cost and Economic Impacts

A. Environmental Impacts of the Proposed Rule on Groundwater Quality

    This proposed action reduces the risk of undetected contamination 
of groundwater resources surrounding ISR facilities both during uranium 
production and after production has ceased. 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 new standards proposed in this action would reduce the risk of 
groundwater degradation both during the ISR operational phase and after 
an ISR operator's license is terminated and the facility is closed. 
This would be achieved through provisions requiring characterization of 
groundwater prior to uranium recovery and standards set to protect 
groundwater from excursions during the operational phase and standards 
for restoration to pre-operating conditions and stability after the 
operational phase ends. These proposed requirements would significantly 
reduce the probability that groundwater down-gradient from an ISR 
facility will become contaminated by radiological and non-radiological 
constituents. Through monitoring and corrective action programs, the 
new proposed standards would ensure potential excursions are detected 
and remedied in a timely manner. The proposed initial and long-term 
stability standards would ensure the ISR aquifer is stable prior to 
closure, reducing the potential for contamination to occur after 
uranium recovery has ceased and the ISR facility's operating license 
has been terminated following closure.

B. Incremental Costs of Complying With the Proposed Rule

    Using information on the uranium extraction industry, the EPA 
estimated incremental costs resulting from this proposal. Under this 
proposal, ISR facilities would be required to complete the following 
additional activities: (1) A comprehensive preoperational 
characterization of the area (including characterization of geochemical 
conditions); (2) monitoring for excursions during the operational and 
restoration phases; (3) three years of initial stability monitoring; 
and (4) long-term stability assessment, with a minimum of three years 
of additional monitoring, with the total duration of the long-term 
stability monitoring determined by the regulatory agency based on 
modeling and monitoring of geochemical conditions.
    Incremental costs attributable to the proposal are costs that would 
be higher under the proposal than they would be if 40 CFR part 192 was 
not revised. If no revisions were made to 40 CFR part 192, ISR 
facilities would be required by the NRC or agreement states to 
characterize preoperational conditions,

[[Page 7423]]

monitor for excursions during operational and restoration phases, and 
monitor after restoration to show that conditions are stable. The EPA 
consulted with the NRC to ensure that its characterization of 
compliance requirements in the absence of the rule accurately reflected 
current trends in the NRC's permit requirements. To estimate 
incremental costs of complying with the proposed rule, the EPA 
estimated the costs of complying with the proposal and then subtracted 
the costs of complying with the NRC's requirements in the absence of 
the rule. EPA requests comment on this approach.
    Under the proposal, the EPA estimates that ISR facilities would 
incur higher costs, for several reasons: (1) More monitoring wells 
would be required under the proposal; (2) more constituents would be 
monitored under the proposal; and/or (3) monitoring during the 
preoperational and stability phases would be required to continue for a 
longer period of time under the proposal. In addition, because the 
overall duration of monitoring prior to closure and license termination 
would be longer under the proposal, other non-monitoring costs would be 
incurred for several additional years, compared to requirements in the 
absence of the proposal.
    To estimate the incremental costs for complying with these 
additional proposed requirements, the EPA used ISR operations listed by 
the U.S. Energy Information Administration as likely affected ISR 
operations and a projected 2017 ISR uranium production of 3.3 million 
pounds. From this analysis, the EPA estimated low, average and high 
incremental costs of complying with the proposal; average incremental 
costs of complying with the proposal at approximately $1.96 per pound 
of uranium and an annual cost of $181,000 to $6.4 million for firms 
owning ISR facilities, depending on the number and scale of the ISR 
facilities they own. Nationally, the EPA estimates the incremental 
total annual cost of the proposal to be approximately $11.9 million, 
including incremental annualized capital costs and monitoring costs 
($4.3 million) and incremental annual non-monitoring costs ($7.6 
million). The EPA's estimated national incremental annualized costs for 
the original proposed rule totaled $13.5 million for monitoring and 
capital costs alone. Since the original proposal, the EPA learned from 
discussions with the NRC that many of the monitoring requirements of 
the proposed rule (and also those of the proposal) would already be 
embodied in expected NRC license requirements in the absence of the 
proposal. In addition, the EPA revised some of the rule's requirements 
to increase flexibility and reduce burden. For these reasons, the 
difference between the monitoring requirements and costs for the 
proposal and those for current practice (the incremental monitoring 
costs of the proposal) are estimated to be considerably lower than the 
estimates for the proposed rule. This reduction in incremental 
monitoring costs is largely offset by including, in response to public 
comment, estimated incremental non-monitoring costs). Overall, the 
EPA's estimate of incremental annualized costs of complying with the 
proposed rule is slightly lower than the costs estimated for the 
original proposal. For additional information regarding the methodology 
used to estimate the costs, see the technical 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.

C. Economic Impacts of the Proposed Rule on the Market for Uranium and 
the Uranium Industry

    The EPA estimated the impact of the proposal on the market for 
uranium using a simplified model of the U.S. market for uranium in 
2017, using 2015 market quantities as a proxy for market quantities in 
2017. EPA requests comment on this approach. The partial equilibrium 
model of the U.S. uranium market estimated market impacts and revealed 
the following: (a) Changes in the quantity of uranium purchased by U.S. 
COOs of nuclear power plants; (b) changes in the sales of domestically 
produced uranium and imports; and (c) changes in the market price for 
uranium. Based on average incremental costs of complying with the 
proposal, the EPA found that the market quantity of uranium purchased 
for use in electric generation is expected to decline by less than 0.01 
percent and the market price to increase by approximately 0.2 percent. 
Domestic ISR facilities are projected to decrease their production by 
approximately 6.7 percent, and imports of uranium are expected to 
increase by 0.4 percent. Because the cost of uranium is a very small 
share of the cost of electricity, the EPA estimates that the cost of 
generating electricity will likely increase by less than 0.1 percent 
due to this action. Although the national total annual cost of the 
proposal (approximately $11.9 million, based on average costs) is well 
below the $100 million threshold that is one of the criteria used to 
identify a significant regulatory action, the industry has only a small 
number of companies operating a small number of ISR facilities.
    The EPA used existing and planned ISR operations and the companies 
that own them as models for the types of facilities and companies 
affected by the proposal. This proposal would affect approximately 15 
ISR facilities that are currently operating or may operate in the near 
future. The 15 ISR facilities are owned by 9 firms. This action would 
apply to the following ISR facilities identified by the Energy 
Information Administration in 2015 as either operating, permitted and 
licensed, developing, or partially permitted and licensed: (1) Crow 
Butte (Nebraska) and (2) Smith Ranch-Highland (Wyoming), both owned by 
Cameco Resources; (3) Alta Mesa (Texas), and (4) Nichols Ranch 
(Wyoming) both owned by Energy Fuels; (5) Willow Creek, (6) Jab and 
Antelope, and (7) Moore Ranch (Wyoming), all owned by Uranium One/
Rosatom; (8) Hobson-La Palangana and (9) Goliad (Texas), both owned by 
Uranium Energy Corp.; (10) Lost Creek (Wyoming), owned by Ur-Energy 
Inc.; (11) Church Rock and (12) Crownpoint (New Mexico), both owned by 
Laramide; (13) Reno Creek (Wyoming), owned by Bayswater; (14) Dewey 
Burdock (South Dakota), owned by Azarga Uranium Corp.; and (15) Ross 
(Wyoming), owned by Peninsula Energy. Three other ISR projects 
(Kingsville Dome, Rosita, and Vasquez, owned by Uranium Resources, 
Inc.) are out of scope for the analysis because they are undergoing 
restoration or reclamation as of 2015. Using the Small Business 
Administration size standard for NAICS code 212291 (i.e., fewer than 
250 employees) all the parent company firms except Cameco Resources and 
Rosatom/Uranium One Americas, Inc. qualify as small businesses. Thus, 
the majority of the firms in NAICS 212291 are small firms.
    To evaluate the magnitude of the economic impacts of the proposed 
revisions to 40 CFR part 192 on firms owning ISR facilities, the EPA 
estimated the incremental costs that would be incurred by affected 
facilities including both monitoring and non-monitoring costs, summed 
costs to the firm-level, and compared each firm's estimated costs to 
estimated or reported firm revenues. EPA requests comment on this 
approach.
    Compiling these estimated costs at the parent company level and 
comparing them to estimated sales or reported sales for the parent 
company, average estimated annualized costs would range from 0.66 
percent to 2.78 percent of

[[Page 7424]]

average company sales for the seven small businesses, and 0.2 percent 
and 2.6 percent for the two large businesses. Of the seven small 
businesses, one firm has cost-to-sales ratio below 1 percent, three 
firms have cost-to-sales ratios between 1 percent and 2 percent, and 
three have cost-to-sales ratios between 2 percent and 3 percent. The 
EPA's estimated costs may overstate actual annual costs, especially for 
ISR facilities with large acreage, because the cost estimates are 
scaled based on the entire wellfield acreage, while ISR facilities 
typically have some wellfields in the operational phase and others in 
various stages of development and restoration or reclamation. Average 
costs based on total acreage may overstate costs incurred at some times 
during the life of the project. Further, the EPA included costs 
associated with all phases of operation for all ISR facilities; this 
would overstate costs for all wellfields currently operating, because 
it includes costs for preoperational monitoring and assessment. In 
addition, the EPA assumed that all ISR facilities would monitor for all 
Table 1 constituents during all phases of monitoring; in fact, the 
regulatory agency may specify monitoring for only those constituents 
expected to be present based on preoperational monitoring, which would 
reduce costs. While some costs may have been over-estimated, the EPA 
considers that values for firm revenues may be under-estimated. For 
facilities for which the EPA estimated sales revenues, the EPA assumed 
that production equaled 25 percent of capacity (based on average levels 
of capacity utilization over the period 2011 to 2015, which is a period 
with relatively low production). The EPA multiplied these relatively 
low estimated production values times market price to estimate revenue. 
For firms for which the EPA used 2015 reported revenues, these revenues 
similarly represent a time period when both production and price are 
lower than usual. Thus, the EPA may have underestimated the revenues 
ISR firms may earn in the future. Because no small firms incur costs 
exceeding 3 percent of sales, and because the costs may be 
overestimated while the future revenues underestimated, the EPA 
concludes that the proposal will not result in a significant impact to 
a substantial number of small entities. In addition to the direct 
economic impacts on ISR producers, the proposal may have indirect 
impacts on businesses that supply inputs to ISR producers (supply chain 
impacts), businesses located in areas near ISR facilities (consumption 
impacts), and local governments in those areas (revenue impacts). Some 
businesses and governments potentially indirectly affected by the 
proposal may be small entities. EPA's analysis projects that the costs 
of the proposal and direct impacts on ISR producers will generally be 
small; indirect impacts are typically smaller than direct impacts. 
Thus, the EPA projects that indirect impacts of the proposal would 
generally be small. Details of the economic analysis are presented in 
the technical 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 the docket for this 
action. EPA requests comment on the economic analysis.

D. Benefits of the Proposed Rule

    The EPA has conducted a qualitative assessment of the benefits of 
the proposal and has identified three principal benefits. First, the 
proposed rule would reduce the potential human health risks associated 
with human exposure to radionuclides, metals and other constituents in 
well water used for drinking and agriculture. The EPA considers water 
contaminated with radionuclides to be a potential pathway for exposure 
to radiation that can cause cancer and other health effects (e.g., 
kidney damage). Likewise, heavy metals and other contaminants can cause 
cancer and/or non-cancer health effects. By reducing the potential for 
contaminants to migrate into aquifers adjacent to ISR facilities, the 
proposal would reduce the potential human exposure to radionuclides, 
heavy metals and other groundwater contaminants from ISR operations and 
thus reduces the potential human health risks from these contaminants.
    Second, the proposal would protect valuable groundwater resources 
for future generations. Groundwater provides a valuable resource that 
is increasingly threatened by population growth and technological 
advances that have significantly increased groundwater extraction. 
Declining groundwater resources, especially in arid regions where ISR 
operations are mostly located, are a growing concern. Although the EPA 
is unable to quantify the value of the groundwater resources that would 
be protected by the proposal, groundwater resources are likely to 
become more valuable over time. By reducing the potential for 
groundwater contamination and ensuring that any migration of 
constituents from ISR operations is detected early, the proposal would 
help protect groundwater from contamination. Rapid detection of 
constituent migration from an ISR operation reduces the overall amount 
of contamination that must be remediated; early detection can trigger 
corrective action before a contaminated plume migrates into overlying 
and underlying aquifers and in areas located down-gradient from ISR 
facilities, thus reducing the risk of exposure to hazardous 
constituents. Reducing the risk of contamination of groundwater also 
protects the surface water bodies to which affected aquifers discharge. 
By combining sufficient duration of stability monitoring with 
hydrogeological and geochemical modeling and other analyses to 
demonstrate that groundwater constituent concentration standards will 
continue to be met, the proposal would reduce the risk that such 
migration of constituents above constituent concentration standards 
might occur after the ISR site is decommissioned and its license 
terminated.
    Finally, the proposed standards would reduce or avoid the costs of 
remediating contaminated groundwater by reducing the potential for 
groundwater contamination to occur and by causing any contamination 
that does occur to be discovered and remedied sooner than would be the 
case if the new standards were not issued. The costs incurred for 
cleaning up a plume of contamination may be significant. To illustrate 
the potential magnitude of the benefits associated with reduced or 
avoided remediation costs, the EPA compared remediation costs for a 
model facility under two scenarios: One without the proposed rule and 
one with the proposed rule. The difference in the total pump and treat 
remediation under the two scenarios illustrates the cost savings that 
could result from the rule for this hypothetical contamination episode. 
Using this approach, the EPA was able to illustrate the benefits of the 
proposed rule to be between $23.7 million and $608 million in avoided 
remediation costs over the entire remediation period for a single 
plume, including capital/well development costs and annual costs. The 
EPA was unable to estimate the potential avoided costs of remediation 
that would result from the proposed rule on a national scale because 
the EPA could not predict the number of incidents of groundwater 
contamination that would require remediation with and without the rule, 
or how long it would take for the groundwater contamination to be 
detected. However, the avoided remediation costs of this rule at the 
national level could be substantial based

[[Page 7425]]

on the estimated avoided remediation costs for a single model plume. 
The EPA requests comment on this approach. For additional information 
regarding the methodology used to estimate avoided costs, see section 
4.2.3 in 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.

VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action that was submitted 
to the OMB for review. This action is considered a significant 
regulatory action because it may ``raise novel legal or policy issues 
arising out of legal mandates, the President's priorities, or the 
principles set forth in the Executive Order.'' Accordingly, the EPA has 
described the need for the proposal, prepared an economic analysis of 
the potential costs and benefits associated with this action, 
considered non-regulatory approaches, and submitted the rule to OMB for 
review. The economic and benefits analysis is contained in the document 
``Economic Analysis: Final Revisions to the Health and Environmental 
Protection Standards for Uranium and Thorium Mill Tailings Rule (40 CFR 
part 192),'' December 2016, available in the docket for this action. 
Any changes made in response to OMB recommendations have been 
documented in the docket.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the provisions of the PRA because it does not impose any reporting 
requirements on affected facilities.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. The 
small entities subject to the requirements of this action are small 
businesses with fewer than 250 employees that are primarily engaged in 
leaching or beneficiation of uranium, radium or vanadium ores as 
defined by NAICS code 212291. No small organizations or small 
governmental entities have been identified that would be impacted by 
this proposed rulemaking.
    The Agency has determined that the seven small firms owning ISR 
facilities may experience an impact to average estimated annualized 
costs of between 0.66 percent and 2.78 percent of average company 
sales, with one firm expected to have a cost-to-sales ratio of below 1 
percent, three firms between 1 percent and 2 percent, and three between 
2 percent and 3 percent. Details of this analysis are presented in the 
technical document titled, ``Economic Analysis: Revisions to the Health 
and Environmental Protection Standards for Uranium and Thorium Mill 
Tailings Rule (40 CFR part 192),'' December 2016, available in the 
docket for this action.

D. Unfunded Mandates Reform Act (UMRA)

    This proposed action does not contain an unfunded mandate of $100 
million or more as described in the UMRA, 2 U.S.C. 1531-1538, and does 
not significantly or uniquely affect small governments. The action 
imposes no enforceable duty on any state, local or tribal governments 
or the private sector. This action contains no regulatory requirements 
or obligations that apply to small governments.

E. Executive Order 13132: Federalism

    This proposed action does not have federalism implications. It will 
not have substantial direct effects on the states, on the relationship 
between the national government and the states, or on the distribution 
of power and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This proposed action does not have tribal implications, as 
specified in Executive Order 13175 (65 FR 67249, November 9, 2000). The 
action imposes requirements on licensees of ISR facilities and not on 
tribal governments. Thus, Executive Order 13175 does not apply to this 
action.
    Consistent with the EPA Policy on Consultation and Coordination 
with Indian Tribes, the EPA solicited and considered information 
submitted by tribal officials during the development of this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    This proposed action is not subject to Executive Order 13045 
because it is not an economically significant regulatory action as 
defined by Executive Order 12866. This action's health and risk 
assessments are contained in the document titled ``Ground Water 
Modeling Studies at In-Situ Leaching Facilities and Evaluation of Doses 
and Risks to Off-Site Receptors from Contaminated Ground Water'' 
available in Docket EPA-HQ-OAR-2012-0788. The EPA evaluated several 
regulatory strategies for assuring groundwater restoration and 
stability at ISR facilities and selected the option providing greatest 
assurance that groundwater systems will remain in a chemically reduced 
state. By setting new groundwater standards, which include improved 
monitoring and requirements to plan for and implement corrective 
measures for excursions and exceedances, this proposed rule reduces 
children's risk of exposure to contaminated groundwater.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use

    This proposed action is not a ``significant energy action'' because 
it is not likely to have a significant adverse effect on the supply, 
distribution or use of energy. This action proposes standards 
applicable for uranium ISR facilities that do not directly impact 
energy supply, distribution or use. The proposed rule would increase 
the costs of domestic uranium producers relative to foreign producers; 
however, because domestic-source uranium generally constitutes between 
10 percent and 15 percent of total uranium purchased by COOs of nuclear 
power plants, the EPA does not expect the proposed rule to have a 
significant impact on uranium quantities or prices available to nuclear 
power generators, and essentially no impact on the quantity or price of 
electricity. Thus, the EPA has concluded that this proposed action is 
not likely to have any adverse effects on productivity, competition, or 
prices in the energy sector.

I. National Technology Transfer and Advancement Act

    This proposed rulemaking does not involve technical standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    The EPA believes that this proposed action does not have 
disproportionately high and adverse human health or environmental 
effects on minority populations, low-income populations or indigenous 
peoples, as specified in Executive Order 12898 (59 FR 7629, February 
16, 1994).

[[Page 7426]]

    The documentation for this decision in contained in the document 
titled ``Ground Water Modeling Studies at In-Situ Leaching Facilities 
and Evaluation of Doses and Risks to Off-Site Receptors from 
Contaminated Ground Water'' available in Docket EPA-HQ-OAR-2012-0788. 
The proposed rule will reduce exposure to all populations by setting 
new groundwater standards, which include improved monitoring and 
requirements for planning for and implementing corrective measures when 
excursions and exceedances occur at ISR facilities. By increasing the 
level of environmental protection for all affected populations, 
including minority and low-income populations, this action will have a 
positive impact on human health and the environment.

List of Subjects in 40 CFR Part 192

    Environmental protection, Hazardous substances, Radiation 
protection, Radioactive materials, Reclamation, Uranium, Waste 
treatment and disposal, Water resources.

    Dated: January 3, 2017.
Gina McCarthy,
Administrator.

    For the reasons stated in the preamble, title 40, Chapter I of the 
Code of Federal Regulations is proposed to be amended as set forth 
below:

PART 192--HEALTH AND ENVIRONMENTAL PROTECTION STANDARDS FOR URANIUM 
AND THORIUM MILL TAILINGS

0
1. The authority citation for 40 CFR part 192 continues to read as 
follows:

    Authority: Sec. 275 of the Atomic Energy Act of 1954, 42 U.S.C. 
2022, as added by the Uranium Mill Tailings Radiation Control Act of 
1978, Pub. L. 95-604, as amended.

Subpart C--Implementation

0
2. Section 192.20 is amended by revising paragraph (b)(3) as follows:


Sec.  192.20  Guidance for implementation.

* * * * *
    (b) * * *
    (3) Compliance with Sec.  192.12(b) may be demonstrated by methods 
that the Department of Energy has approved for use or methods that the 
implementing agencies determine are adequate. Residual radioactive 
materials should be removed from buildings exceeding 0.03 WL so that 
future replacement buildings will not pose a hazard [unless removal is 
not practical, see Sec.  192.21(c)]. However, ventilation devices and 
other radon mitigation methods recommended by the EPA may provide 
reasonable assurance of reductions from 0.03 WL to below 0.02 WL. In 
unusual cases, indoor radiation may exceed the levels specified in 
Sec.  192.12(b) due to sources other than residual radioactive 
materials. Remedial actions are not required in order to comply with 
the standard when there is reasonable assurance that residual 
radioactive materials are not the cause of such an excess.
* * * * *

Subpart D [Amended]

0
3. The heading for Subpart D is revised to read as set forth below.
0
4. Section 192.31 is amended by revising paragraphs (a), (f), and the 
second sentence of paragraph (m).
    The revisions read as follows:

Subpart D--Standards for the Management of Uranium Byproduct 
Materials

* * * * *


Sec.  192.31  Definitions and cross-references.

    (a) Unless otherwise indicated in this subpart, all terms shall 
have the same meaning as in Title II of the Uranium Mill Tailings 
Radiation Control Act of 1978, subparts A and B of this part, or parts 
190, 260, 261, and 264 of this chapter. For the purposes of this 
subpart, the terms ``waste,'' ``hazardous waste'' and related terms, as 
used in parts 260, 261, and 264 of this chapter, shall apply to 
byproduct material.
* * * * *
    (f) Disposal area means the region within the perimeter of an 
impoundment or pile containing uranium byproduct materials to which the 
post-closure requirements of Sec.  192.32(b)(1) apply.
* * * * *
    (m) * * * This term shall not be construed to include extraordinary 
measures or techniques that would impose costs that are grossly 
excessive as measured by practice within the industry or one that is 
reasonably analogous (such as, by way of illustration only, 
unreasonable overtime, staffing or transportation requirements, etc., 
considering normal practice in the industry; laser fusion of soils, 
etc.), provided there is reasonable progress toward emplacement of a 
permanent radon barrier. * * *
* * * * *
0
5. Section 192.32 is amended by revising paragraph (a)(2)(v) as 
follows:


Sec.  192.32  Standards.

    (a) * * *
    (2) * * *
    (v) The functions and responsibilities designated in part 264 of 
this chapter as those of the ``Regional Administrator'' with respect to 
``facility permits'' shall be carried out by the regulatory agency.
* * * * *
0
6. Part 192 is amended by adding subpart F to read as follows:
Subpart F--Public Health, Safety and Environmental Protection Standards 
for Byproduct Materials Produced by Uranium In-Situ Recovery
Sec.
192.50 Purpose and applicability.
192.51 Definitions and cross-references.
192.52 Standards.
192.53 Monitoring programs, modeling and other analysis.
192.54 Alternate concentration limits.
192.55 Corrective action program.
192.56 Effective date.

Subpart F--Public Health, Safety and Environmental Protection 
Standards for Byproduct Materials Produced by Uranium In-Situ 
Recovery


Sec.  192.50  Purpose and applicability.

    (a) This rule contains standards of general application that the 
regulatory agency will implement and enforce to protect groundwater at 
in-situ uranium recovery facilities.
    (b) This subpart applies to the management of uranium byproduct 
materials prior to, during and following the processing of uranium ores 
utilizing uranium in-situ recovery methods, and to the protection of 
groundwater at such facilities. Within three years of the effective 
date of this rule, the regulatory agency shall apply these standards of 
general application to ISR facilities licensed to process uranium 
byproduct material.


Sec.  192.51  Definitions and cross-references.

    (a) Unless otherwise indicated in this subpart, all terms shall 
have the same meaning as in Title II of the Uranium Mill Tailings 
Radiation Control Act of 1978, subparts A, B, and D of this part, or 
parts 190, 260, 261, and 264 of this chapter.
    (b) Agreement State. Any State with which the Nuclear Regulatory 
Commission (NRC) or the Atomic Energy Commission has entered into an 
effective agreement under subsection 274b of the Atomic Energy Act.
    (c) Alternate Concentration Limit (ACL). An alternate concentration 
limit approved by the regulatory agency for a groundwater constituent 
after the regulatory agency determines that best practicable 
restoration activities have been completed and that concentrations of 
the constituent cannot be restored to the applicable standards in 40 
CFR 192.52(c)(1)(i) or (c)(1)(ii), following the process prescribed in 
Sec.  192.54.

[[Page 7427]]

    (d) Aquifer. A geological formation, group of formations, or part 
of a formation that is capable of yielding a significant amount of 
water to a well or spring. See 40 CFR 144.3.
    (e) Background. The condition of groundwater, including the 
radiological and non-radiological constituent concentrations, prior to 
the beginning of ISR operations.
    (f) Constituent. A detectable component within the groundwater.
    (g) Constituent concentration standard. A concentration limit for a 
constituent in groundwater set according to Sec.  192.52(c)(1).
    (h) Exceedance of a constituent concentration standard. An 
exceedance has occurred when, during stability monitoring, a 
constituent concentration standard is exceeded at any point of 
compliance well, as determined by the regulatory agency.
    (i) Excursion. The movement of fluids containing lixiviant or 
uranium byproduct materials from the production zone into surrounding 
groundwater. An excursion is considered to have occurred when two 
indicator parameters (e.g., chloride, conductivity, total alkalinity) 
exceed their respective upper control limits in any excursion 
monitoring well, or, as determined by the regulatory agency, when one 
indicator parameter significantly exceeds its upper control limit in 
any excursion monitoring well.
    (j) Excursion Monitoring Wells. Wells located around the perimeter 
of the production zone, including in overlying and underlying aquifers, 
which are used to detect any excursions from the production zone. These 
wells may also be used to demonstrate compliance with stability 
standards once restoration has been completed.
    (k) Extraction Well. Well used to extract uranium enriched 
solutions from the ore-bearing aquifer; also known as a production 
well. Extraction and injection wells may be converted from one use to 
the other.
    (l) Indicator Parameter. A constituent, such as chloride, 
conductivity or total alkalinity, whose upper control limit is used to 
identify an excursion. Indicator parameters are not necessarily 
contaminants, but relate to geochemical conditions in groundwater.
    (m) Initial Stability Phase. The period immediately following the 
restoration phase when the wellfield is monitored to determine if and 
when the initial stability standards are met. This is the period in 
which provisional alternate concentration limits may be established and 
implemented, if necessary.
    (n) Injection Well. A well into which fluids are being injected. 
See 40 CFR 144.3.
    (o) In-Situ Recovery (ISR). 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 body. 
The process does not require the extraction of ore from the ground. The 
lixiviant is injected, passes through the ore body, and mobilizes the 
uranium; the uranium-bearing solution is pumped to the surface via 
extraction wells. The pregnant leach solution is processed to extract 
the uranium.
    (p) Listed Constituent. One of the twelve groundwater constituents 
specified in Table 1 to this subpart.
    (q) Lixiviant. A liquid medium used to recover uranium from 
underground ore bodies through in-situ recovery. This liquid medium 
typically contains native groundwater and an added oxidant, such as 
oxygen or hydrogen peroxide, as well as sodium carbonate, sodium 
bicarbonate or carbon dioxide.
    (r) Long-Term Stability Phase. The period after the constituent 
concentration standards have been met and initial stability has been 
demonstrated according to Sec.  192.52(c)(2), as determined by the 
regulatory agency. The regulatory agency sets the extent of time the 
facility remains in the long-term stability phase.
    (s) Maximum Constituent Concentration. The maximum permissible 
level of a constituent in groundwater, as established under Sec.  
192.52(c)(1).
    (t) Maximum Contaminant Level (MCL). The maximum permissible level 
of a contaminant in water delivered to any user of a community water 
system. See 40 CFR 141.2.
    (u) Monitoring Wells. Wells used to obtain groundwater levels and 
water samples for the purpose of determining the hydrogeological regime 
and the amounts, types and distribution of constituents in the 
groundwater. Wells are located in the production zone, around the 
perimeter of the production zone and in overlying and underlying 
aquifers.
    (v) Operational Phase. The time period during which uranium 
recovery occurs. Operation begins when extraction begins and lixiviant 
is injected. Operation ends when the operator permanently ceases 
injection of lixiviant and recovery of uranium-bearing solution for 
processing purposes. The operational phase includes periods during 
which the ISR temporarily ceases uranium recovery (i.e., when the ISR 
is in ``stand-by'' mode) but the ISR still needs to maintain 
appropriate groundwater controls to prevent contaminants from leaving 
the production zone.
    (w) Overlying Aquifer. An aquifer that is immediately vertically 
shallower than (i.e., directly above) the production zone aquifer.
    (x) Point(s) of Compliance. Locations where groundwater protection 
standards are generally applied. The regulatory agency reviews and 
approves the location of points of compliance for the wellfield. During 
all phases of ISR, points of compliance should include excursion 
monitoring well locations; during the initial and long-term stability 
phases, points of compliance should also include wells in the 
production zone.
    (y) Point(s) of Exposure. Used in setting ACLs, points of exposure 
are 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 that point of exposure must be protective of the 
receptor.
    (z) Preoperational Monitoring. Measurement of groundwater 
conditions in the production zone, up and down gradient of the 
production zone and in overlying and underlying aquifers, when present. 
Preoperational monitoring plans are subject to approval by the 
regulatory agency prior to the operational phase.
    (aa) Production Zone. The portion of the aquifer in which in-situ 
recovery occurs. The production zone lies within the wellfield.
    (bb) Regulatory Agency. The NRC or an Agreement State.
    (cc) Restoration (Act of). The process of remediating groundwater 
to a state where it meets the constituent concentration standards 
listed in 40 CFR 192.52(c)(1).
    (dd) Restoration Phase. The period immediately after lixiviant 
injection permanently ceases, during which restoration activities 
occur.
    (ee) Underlying Aquifer. An aquifer that is immediately vertically 
deeper (i.e., directly below) than the production zone aquifer.
    (ff) Upper Control Limit (UCL). Upper control limits are maximum 
concentrations for excursion indicator parameters that, when exceeded, 
indicate lixiviant or other constituents are migrating beyond the 
production zone.
    (gg) Uranium Recovery Facility. A facility licensed to process 
uranium ores primarily for the purpose of recovering

[[Page 7428]]

uranium (and/or thorium) and to manage uranium (and/or thorium) 
byproduct materials that result from processing of ores. Common names 
for these facilities include, but are not limited to, the following: A 
conventional uranium mill, an in-situ recovery (or leach) facility, and 
a heap leach facility or pile.
    (hh) Wellfield. The area of an ISR operation that encompasses the 
array of injection, extraction and monitoring wells, ancillary 
equipment and interconnected piping employed in the uranium in-situ 
recovery process. The area of the wellfield exceeds that of the 
production zone.


Sec.  192.52  Standards.

    (a) No later than three years after the effective date of this 
rule, all operating wellfields, new wellfields and expansions of 
wellfields at ISR facilities must meet the standards in this section. 
These standards do not apply to those wellfields at licensed ISR 
facilities that, within three years of the effective date of this rule, 
are in and remain in the restoration, initial stability monitoring or 
long-term stability monitoring phases.
    (b) Surface impoundments. (1) Surface impoundments associated with 
ISR activities shall conform to the standards of Sec.  192.32.
    (2) Disposal of solid uranium byproduct materials produced by ISR 
activities shall conform to the standards in Sec.  192.32.
    (c) Groundwater protection standards. The constituent concentration 
standards, in paragraph (c)(1) of this section, must be met after 
restoration or corrective action and are also incorporated into the 
initial and long-term stability standards. The initial stability 
standards, in paragraph (c)(2) of this section, are a measure of the 
effectiveness of restoration and must be met prior to meeting the long-
term stability standards. The long-term stability standards, in 
paragraph (c)(3) of this section, must be met prior to decommissioning 
and termination of the ISR facility's license.
    (1) Constituent concentration standards. The licensee shall propose 
and the regulatory agency shall review and approve constituent 
concentration standards for each of the constituents listed in Table 1 
to this subpart that are identified by the licensee and approved by the 
regulatory agency as being present or affected by operations in the 
production zone. The limit for each constituent is the highest level of 
the following values:
    (i) That constituent's preoperational background level in and 
around the wellfield, as determined by preoperational monitoring 
conducted under Sec.  192.53(a); or
    (ii) the lowest regulatory standard for that constituent found in 
40 CFR 141.61, 141.62, 141.66, 141.80, 143.3, 264.94, or Table 1 of 
subpart A of this part. For any constituent not listed in Table 1 to 
this subpart, but designated by the regulatory agency for monitoring, a 
constituent concentration standard at or above the background level 
should be established from the values in 40 CFR parts 141, 143 or 264, 
if such values exist. For a constituent not found in 40 CFR parts 141, 
143 or 264, the constituent concentration standard above the background 
level should be established at a concentration level that represents a 
cumulative excess lifetime risk no greater than 10-\4\ to an 
average individual;
    (iii) an alternate concentration limit for that constituent as 
approved by the regulatory agency under Sec.  192.54.

     Table 1 to Subpart F--Maximum Concentration of Constituents for
              Groundwater Protection at ISR Facility Sites
------------------------------------------------------------------------
              Constituent                     Maximum concentration
------------------------------------------------------------------------
Arsenic, Barium, Cadmium, Chromium,      The constituent concentration
 Lead, Mercury, Selenium, Silver,         standard is the primary or
 Nitrate (as N), Molybdenum, Radium-226   secondary MCL listed in 40 CFR
 and radium-228 (combined), Uranium       141.61, 141.62, 141.66,
 (uranium-234, uranium-235 and uranium-   141.80, and 143.3, the maximum
 238 combined).                           concentration of hazardous
                                          constituents for groundwater
                                          protection under 40 CFR
                                          264.94, or the maximum
                                          constituent concentration
                                          specified in Table 1 to
                                          subpart A of this part,
                                          whichever value is the lowest.
                                         Where a background
                                          concentration is determined to
                                          be higher than the lowest
                                          value in the applicable
                                          regulations, the background
                                          concentration will serve as
                                          the constituent concentration
                                          standard.
------------------------------------------------------------------------

    (2) Initial Stability Standards. The licensee must demonstrate to 
the satisfaction of the regulatory agency that groundwater conditions 
are stable by showing three consecutive years of quarterly monitoring 
results with no statistically significant increasing trends that would 
exceed the constituent concentration standards at the 95 percent 
confidence level. This showing shall be based on monitoring data 
collected in accordance with Sec.  192.53(c).
    (3) Long-term Stability Standards. After meeting the initial 
stability standards in paragraph (c)(2) of this section, the licensee 
must demonstrate to the satisfaction of the regulatory agency that 
groundwater conditions will remain stable into the future by showing:
    (i) Three consecutive years of quarterly monitoring results 
demonstrating no statistically significant increasing trends that would 
exceed the constituent concentration standards at the 95 percent 
confidence level. This showing shall be based on monitoring data 
collected in accordance with the Sec.  192.53(d); and
    (ii) the applicable constituent concentration standards will 
continue to be met into the future. This showing shall be based on the 
information collected under Sec.  192.53(d), including monitoring data, 
geochemical modeling, and other analysis required by the regulatory 
agency.


Sec.  192.53  Monitoring programs, modeling and other analysis.

    Licensees subject to this subpart must conduct a groundwater 
monitoring program, subject to review and approval by the regulatory 
agency, at prospective and licensed ISR wellfields. The components of 
the program include pre-operational monitoring to determine 
statistically valid background levels, excursion monitoring to identify 
and correct excursions, and initial and long-term stability monitoring. 
This program shall address all phases of the uranium recovery 
activities and must be conducted as follows:
    (a) General monitoring program requirements and preoperational 
monitoring.
    (1) A sufficient number of wells, at appropriate locations and 
depths, shall

[[Page 7429]]

be installed in such a manner as to yield representative samples in 
order to define the groundwater flow regime and measure preoperational 
conditions and water quality during background determination, 
operations, restoration, initial stability and long-term stability.
    (2) All monitoring wells must be installed and developed as 
directed by the regulatory agency to maintain well integrity, allow for 
accurate sample collection and prevent contamination of samples.
    (3) The preoperational monitoring shall include the production zone 
and areas immediately surrounding the production zone, as identified by 
the regulatory agency, including up- and down-gradient areas outside of 
the production zone.
    (4) During the preoperational monitoring effort, relevant data 
documenting geology, hydrology and geochemistry for radiological and 
non-radiological constituents shall be collected as required by the 
regulatory agency, both in the production zone and in surrounding areas 
that may be affected by the ISR operations.
    (i) The monitoring effort shall be of sufficient scope and duration 
to adequately characterize temporal (e.g., no less than one year where 
seasonal variation is expected) and spatial variations in groundwater, 
using statistically valid approaches to evaluate groundwater quality 
trends and ensure adequate background characterization of the wellfield 
and adjacent areas. If monitoring is to be conducted for less than one 
year, it must be sufficient to demonstrate that the measured 
constituents do not reflect impacts associated with well construction.
    (ii) Preoperational monitoring shall be focused on determining 
background concentrations of constituents and indicator parameters in 
the following locations:
    (A) Points of compliance within the proposed production zone; and
    (B) Points of compliance outside the production zone including 
point of compliance screened in potentially affected overlying and 
underlying aquifers (when present); and points of compliance screened 
in upgradient and downgradient aquifers (when present).
    (5) The licensee shall employ appropriate statistical techniques to 
analyze background concentrations measured in individual wells within 
the wellfield and in any other wells identified by the regulatory 
agency for the purpose of determining constituent concentration 
standards. Background concentrations used to establish the constituent 
concentration standards may be representative of individual wells, 
multiple wells, or all wells within the proposed production zone and 
are subject to review and approval by the regulatory agency.
    (6) Radiological and non-radiological constituents to be monitored 
during the preoperational phase shall include:
    (i) All constituents listed in Table 1 of this subpart;
    (ii) Constituents and parameters as determined by the regulatory 
agency to be necessary to characterize the geochemistry of the 
groundwater and to demonstrate that the applicable constituent 
concentration standards have been met and will continue to be met into 
the future; and
    (iii) Any additional constituents or parameters required by the 
regulatory agency, such as metals potentially mobilized by the recovery 
process.
    (b) Excursion Monitoring.
    (1) Indicator parameters, as established by the regulatory agency, 
shall be monitored in excursion monitoring wells surrounding the 
production zone, including aquifers above and below the production 
zone, at a minimum throughout the operational and restoration phases of 
ISR activities.
    (2) If an excursion is detected as evidenced by indicator 
parameters exceeding established upper control limits, as determined by 
the regulatory agency, corrective action under Sec.  192.55 must be 
initiated and constituents listed in Table 1 of this subpart expected 
to be present (e.g., uranium, radium, arsenic, and selenium) and any 
other constituent identified by the regulating agency shall be 
monitored until the excursion is controlled.
    (c) Initial Stability Monitoring.
    (1) Once the regulatory agency determines restoration is complete, 
the licensee shall begin its initial stability monitoring as described 
in paragraphs (c)(2), (3), and (4) of this section to meet its initial 
stability standards as described in Sec.  192.52(c)(2).
    (2) The constituents to be monitored at the points of compliance 
shall include:
    (i) All constituents having a constituent concentration standard 
and expected to be present, as determined by the regulatory agency 
under Sec.  192.52(c)(1);
    (ii) Any additional constituents required by the regulatory agency, 
such as:
    (A) Constituents and parameters necessary to characterize the 
geochemistry of the groundwater and other analysis to demonstrate that 
the applicable constituent concentration standards have been met and 
will continue to be met into the future;
    (B) Components of the lixiviant fluids injected during uranium 
recovery and any fluids injected during restoration; or
    (C) Metals potentially mobilized by the uranium recovery process 
that could reasonably be expected to be found in the groundwater.
    (3) If the licensee finds that the initial stability standard in 
Sec.  192.52(c)(2) cannot be demonstrated for one or more constituents, 
the regulatory agency may:
    (i) Require the licensee to resume active restoration efforts; or
    (ii) After all best practicable active restoration activities have 
been completed, establish a provisional alternate concentration limit 
according to the requirements of Sec.  192.54. Once initial stability 
according to the standard in Sec.  192.52(c)(2) at the provisional 
alternate concentration limit has been documented, the regulatory 
agency may establish a final alternate concentration limit according to 
the requirements of Sec.  192.54.
    (4) If the regulatory agency determines that a constituent exceeds 
a constituent concentration standard in Sec.  192.52(c)(1) at a point 
of compliance, the licensee, as directed by the regulatory agency, must 
undertake corrective action under Sec.  192.55 until the regulatory 
agency determines that the exceedance of the constituent concentration 
standard is adequately remedied.
    (d) Long-term stability monitoring, modeling and other analysis.
    (1) Once the regulatory agency determines the initial stability 
standards have been met, the licensee shall begin conducting long-term 
stability monitoring as described in paragraph (d)(2) of this section 
to demonstrate it meets its long-term stability standards, established 
under Sec.  192.52(c)(3).
    (2) The constituents to be monitored at the points of compliance 
shall include:
    (i) All constituents having a constituent concentration standard 
expected to be present, as determined by the regulatory agency under 
Sec.  192.52(c)(1);
    (ii) Any additional constituents required by the regulatory agency, 
such as:
    (A) Constituents and parameters necessary to characterize the 
geochemistry of the groundwater and modeling and other analysis to 
demonstrate that the applicable constituent concentration standards 
have been met and will continue to be met into the future;
    (B) Components of the lixiviant fluids injected during uranium 
recovery and any fluids injected during restoration; or
    (C) Metals potentially mobilized by the uranium recovery process 
that could

[[Page 7430]]

reasonably be expected to be found in the groundwater.
    (3) If the regulatory agency finds that one or more constituents at 
a point of compliance within the wellfield exceeds a constituent 
concentration standard as defined in Sec.  192.52(c)(1) then, as 
directed by the regulatory agency, the licensee must undertake 
corrective action under Sec.  192.55 until the regulatory agency 
determines that the exceedance of the constituent concentration 
standard(s) is adequately remedied.
    (4) If the licensee finds that the long-term stability standard in 
Sec.  192.52(c)(3) cannot be demonstrated for one or more constituents, 
the regulatory agency may:
    (i) Require the licensee to resume active restoration efforts; or
    (ii) After all best practicable active restoration activities have 
been completed, establish an alternate concentration limit according to 
the requirements of Sec.  192.54.
    (5) In addition to the long-term stability monitoring requirements 
described in paragraph (d)(2) of this section, the licensee must 
provide to the regulatory agency geochemical modeling and other 
analysis sufficient to demonstrate that the long-term stability 
standard in Sec.  192.52(c)(3) has been met.
    (6) The licensee must continue its long-term stability monitoring 
until the regulatory agency determines that the long-term stability 
standard in Sec.  192.52(c)(3) has been met and releases the facility 
from monitoring.


Sec.  192.54  Alternate Concentration Limits.

    (a) Provisional Alternate Concentration Limits. The regulatory 
agency may establish a provisional alternate concentration limit within 
the production zone for any constituent that meets the following 
conditions:
    (1) The regulatory agency determines that all best practicable 
active restoration activities have been completed in accordance with 
the license, and that the previously approved constituent concentration 
standard under Sec.  192.52(c)(1)(i) or (ii) are not reasonably 
achievable; and
    (2) The constituent will not pose a substantial present or 
potential hazard to human health or the environment as long as the 
provisional alternate concentration limit is not exceeded; and
    (3) The constituent concentration standard, as determined under 
paragraph (c)(1) of this section, is satisfied at all points of 
exposure in the wellfield and in surrounding aquifers.
    (b) Final Alternate Concentration Limits. The regulatory agency may 
approve a final alternate concentration limit provided that the 
following conditions are met:
    (1) The licensee has demonstrated initial groundwater stability as 
defined in Sec.  192.52(c)(2); and (2) The constituent will not pose a 
substantial present or potential future hazard to human health or the 
environment as long as the final alternate concentration limit is not 
exceeded.
    (c) In deciding whether to approve a provisional or a final 
alternate concentration limit, the regulatory agency shall consider, at 
a minimum, the following factors:
    (1) Potential adverse effects on groundwater quality, considering:
    (i) The physical and chemical characteristics of constituents in 
the groundwater at the site, including their potential for migration;
    (ii) The hydrogeological characteristics (e.g., groundwater 
velocity) of the site and surrounding land;
    (iii) The quantity of groundwater and the direction of groundwater 
flow;
    (iv) The proximity and withdrawal rates of local groundwater users;
    (v) The current and anticipated future uses of groundwater in the 
region surrounding the site;
    (vi) The existing quality of groundwater, including other sources 
of contamination and their cumulative impact on groundwater quality;
    (vii) The potential for health risks caused by human exposure to 
constituents;
    (viii) The potential damage to wildlife, crops, vegetation, and 
physical structures caused by exposure to constituents; and
    (ix) The persistence and permanence of the potential adverse 
effects.
    (2) Potential adverse effects on hydraulically-connected surface-
water quality, considering:
    (i) The volume and physical and chemical characteristics of the 
groundwater at the site;
    (ii) The hydrogeological characteristics of the site and 
surrounding land;
    (iii) The quantity and quality of groundwater, and the direction of 
groundwater flow;
    (iv) The patterns of rainfall in the region;
    (v) The proximity of the site to surface waters;
    (vi) The current and future uses of surface waters in the region 
surrounding the site and any water quality standards established for 
those surface waters;
    (vii) The existing quality of hydraulically-connected surface 
water, including other sources of contamination and their cumulative 
impact on surface water quality;
    (viii) The potential for health risks caused by human exposure to 
constituents;
    (ix) The potential damage to wildlife, crops, vegetation, and 
physical structures caused by exposure to constituents; and
    (x) The persistence and permanence of the potential adverse 
effects.
    (3) The presence of any underground source of drinking water.


Sec.  192.55  Corrective action program.

    (a) A corrective action program shall be developed by the licensee 
and approved by the regulatory agency for each ISR site at the time of 
licensing. The plan shall address a range of possible scenarios (e.g., 
types and routes of potential excursions) and list options for 
corrective action for operational through long-term stability phases. 
If an excursion is detected at a licensed ISR facility at any time, a 
constituent concentration standard is exceeded during the initial or 
long-term stability phases, or the regulatory agency is concerned about 
an increasing trend in stability monitoring results, the applicable 
portions of the corrective action program shall be initiated as soon as 
is practicable, and in no event later than 60 days after such an 
occurrence. With the objective of returning constituent concentration 
levels in groundwater to the constituent concentration standards 
established under Sec.  192.52(c)(1), the corrective action program 
shall address removing constituents at the point of compliance or 
treating them in place.
    (b) The licensee shall continue corrective action measures to the 
extent necessary to achieve and maintain compliance with the 
constituent concentration standards in Sec.  192.52(c)(1). The 
regulatory agency will determine when the licensee may terminate 
corrective action measures based on data from the groundwater 
monitoring program and other information that provides reasonable 
assurance that the constituent concentration standards in Sec.  
192.52(c)(1) will not be exceeded.
    (c) Upon termination of any corrective action initiated during 
long-term stability monitoring, the licensee shall then be subject to 
the initial and long-term stability standards specified in Sec.  
192.53(c)(2) and (3).


Sec.  192.56  Effective date.

    Subpart F shall be effective on [60 DAYS AFTER DATE OF PUBLICATION 
OF FINAL RULE IN FEDERAL REGISTER].

[FR Doc. 2017-00573 Filed 1-18-17; 8:45 am]
 BILLING CODE 6560-50-P


