Document ID: EPA-HQ-OAR-2008-0218-0216
Agency: epa
Document Type: Rule
Title: National Emissions Standards: Radon Emissions from Operating Mill Tailings
Posted Date: 2017-01-17T05:00Z

[Federal Register Volume 82, Number 10 (Tuesday, January 17, 2017)]
[Rules and Regulations]
[Pages 5142-5180]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-31425]

[[Page 5141]]

Vol. 82

Tuesday,

No. 10

January 17, 2017

Part III

 Environmental Protection Agency

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 40 CFR Part 61

 Revisions to National Emission Standards for Radon Emissions From 
Operating Mill Tailings; Final Rule

  Federal Register / Vol. 82 , No. 10 / Tuesday, January 17, 2017 / 
Rules and Regulations  

[[Page 5142]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 61

[EPA-HQ-OAR-2008-0218; FRL-9957-54-OAR]
RIN 2060-AP26

Revisions to National Emission Standards for Radon Emissions From 
Operating Mill Tailings

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is taking final 
action to revise certain portions of the National Emission Standards 
for Hazardous Air Pollutants (NESHAP) for Radon Emissions from 
Operating Mill Tailings. The revisions for this final action are based 
on the EPA's determination as to what constitutes generally available 
control technology or management practices (GACT) for this area source 
category. We are also adding new definitions to the NESHAP, revising 
existing definitions and clarifying that the NESHAP also applies to 
uranium recovery facilities that extract uranium through the in-situ 
leach method and the heap leach method.

DATES: This rule is effective on March 20, 2017.

ADDRESSES: The EPA has established a docket for this action under 
Docket ID No. EPA-HQ-OAR-2008-0218. All documents in the docket are 
listed on the http://www.regulations.gov Web site. Although listed in 
the index, some information is not publicly available, e.g., 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Certain other material, such as 
copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available electronically through http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Dan Schultheisz, Office of Radiation 
and Indoor Air, Radiation Protection Division, Mail code 6608T, U.S. 
Environmental Protection Agency, 1200 Pennsylvania Ave. NW., 
Washington, DC 20460; telephone number: 202-343-9290; fax number: 202-
343-2304; email address: schultheisz.daniel@epa.gov. You may also 
access the EPA Web site to find information related to this rulemaking 
at https://www.epa.gov/radiation/.

SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us'' and 
``our'' refer to the EPA.
    Preamble Acronyms and Abbreviations. We use the following acronyms 
and abbreviations in this document:

AEA--Atomic Energy Act
ALARA--As low as reasonably achievable
BID--Background information document
CAA--Clean Air Act
CAAA--Clean Air Act Amendments of 1990
CCAT--Colorado Citizens Against Toxic Waste
CFR--Code of Federal Regulations
Ci--Curie, a unit of radioactivity equal to the amount of a 
radioactive isotope that decays at the rate of 3.7 x 10\10\ 
disintegrations per second
DOE--U.S. Department of Energy
EIA--Economic impact analysis
EO--Executive Order
EPA--U.S. Environmental Protection Agency
FR--Federal Register
GACT--Generally Available Control Technology
HAP--Hazardous Air Pollutant
ISL--In-situ leach uranium recovery, also known as in-situ recovery 
(ISR)
mrem--millirem, 1 x 10-\3\ rem--a unit of radiation 
exposure
MACT--Maximum Achievable Control Technology
MOU--Memorandum of Understanding
NESHAP--National Emission Standard for Hazardous Air Pollutants
NRC--U.S. Nuclear Regulatory Commission
NTAA--National Tribal Air Association
OMB--Office of Management and Budget
pCi--picocurie, 1 x 10-\12\ curie
Ra-226--Radium-226
Rn-222--Radon-222
Radon flux--A term applied to the amount of radon crossing a unit 
area per unit time, as in picocuries per square centimeter per 
second (pCi/m\2\/sec)
RCRA--Resource Conservation and Recovery Act
Subpart W--National Emission Standards for Radon Emissions from 
Operating Mill Tailings at 40 CFR 61.250-61.256
SWIPR--Subpart W Impoundment Photographic Reporting
tpy--tons per year
U3O8--uranium oxide, also known as 
``yellowcake''
UMTRCA--Uranium Mill Tailings Radiation Control Act of 1978
U.S.C.--United States Code

    Background Information. In this action we are finalizing changes to 
the NESHAP for Radon Emissions from Operating Mill Tailings. These 
changes were proposed on May 2, 2014 (79 FR 25388) as part of a review 
of pre-1990 NESHAPs pursuant to Clean Air Act Section 112(q)(1). After 
review of the public comments we have made some changes to the rule 
since the proposal, and these will be discussed later in this document. 
We summarize some of the more significant comments received regarding 
the proposed rule and provide our responses in this preamble. A summary 
of all other public comments on the proposal and the EPA's responses to 
those comments is provided in the ``Summary and Response to Public 
Comments'' document, which is available in Docket ID No. EPA-HQ-OAR-
2008-0218. The ``track changes'' version of the regulatory language 
that incorporates the changes in this final action resulting from 
review by the Office of Management and Budget (OMB) is also available 
in the docket for this rulemaking.
    Outline. The information in this preamble is organized as follows:

I. General Information
    A. Executive Summary
    1. Introduction
    2. Provisions of the 1989 Rule
    3. Provisions of the Final Rule
    4. Key Changes to the Proposal
    5. Economic Impacts
    6. Public Engagement
    B. Does this action apply to me?
    C. Where can I get a copy of this document and other related 
information?
    D. Judicial Review and Administrative Reconsideration
II. Background
    A. What is the Agency's legal authority for taking this action?
    B. What source category is affected by the final rule?
    C. How does Subpart W regulate HAP emissions from the source 
category?
    D. What changes to Subpart W did we propose?
    E. Comments on the Proposed Rule
III. What Final Amendments Are We Issuing With This Action?
    A. Application of Generally Available Control Technologies 
(GACT) to Uranium Recovery Facilities
    B. Definitions, References and Conforming Editorial Revisions
    C. What are the recordkeeping, notification and reporting 
requirements?
IV. What is the rationale for our final decisions and amendments to 
Subpart W?
    A. Legal Authorities and GACT
    1. What is the legal authority for GACT standards and management 
practices in the final rule?
    2. What key comments did we receive on our legal authorities and 
the GACT approach?
    B. Retaining the Radon Flux Requirement for Impoundments in 
Existence on December 15, 1989
    1. How did we address the radon flux standard in the proposed 
and final rules?
    2. What did our updated risk assessment tell us?
    3. What key comments did we receive on the radon flux standard?
    C. GACT for Conventional Impoundments Constructed After December 
15, 1989
    1. How did we address conventional impoundments constructed 
after December 15, 1989 in the proposed and final rules?

[[Page 5143]]

    2. What key comments did we receive on conventional impoundments 
constructed after December 15, 1989?
    D. GACT for Heap Leach Piles
    1. How did we address heap leach piles in the proposed and final 
rules?
    2. What key comments did we receive on heap leach piles?
    E. GACT for Non-Conventional Impoundments
    1. How did we address non-conventional impoundments in the 
proposed and final rules?
    2. What key comments did we receive on non-conventional 
impoundments?
    F. Definitions, References and Conforming Editorial Revisions
    1. How did we address definitions, references and conforming 
editorial revisions in the proposed and final rules?
    2. What key comments did we receive on definitions, references 
and conforming editorial revisions?
V. Summary of Environmental, Cost and Economic Impacts
    A. What are the air impacts?
    B. What are the cost and economic impacts?
    C. What are the non-air environmental impacts?
VI. Statutory and Executive Orders Review
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use
    I. National Technology Transfer and Advancement Act (NTTAA)
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    K. Congressional Review Act (CRA)

I. General Information

A. Executive Summary

1. Introduction
    This final rule amends requirements promulgated in 1989 under the 
Clean Air Act to control emissions of radon-222 from operating 
structures used to manage uranium byproduct material or tailings \1\ at 
uranium recovery facilities. The rule does not apply to disposal of 
uranium byproduct material or tailings. The rule retains monitoring 
requirements for certain uranium byproduct material or tailings 
impoundments in existence on or before December 15, 1989 and 
establishes generally available control technology or management 
practices (GACT) for other impoundments and heap leach piles. This 
final rule completes the EPA's obligation under the requirements of CAA 
section 112(q)(1) to ``review, and if appropriate, revise'' 40 CFR part 
61, subpart W (hereafter Subpart W).
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    \1\ The EPA first defined the term ``uranium byproduct material 
or tailings'' in 1986 (51 FR 34066). The 1986 and 1989 rulemakings 
were primarily concerned with, but not limited to, conventional mill 
tailings as the most significant source of radon. We used the term 
``tailings'' throughout those rulemakings for simplicity, reflecting 
that rulemaking emphasis. We understand that this has contributed to 
the impression among some stakeholders that Subpart W cannot apply 
to materials other than the mostly solid wastes resulting from 
conventional milling that are managed, and ultimately disposed, in 
permanent impoundments. We are reiterating in this action that the 
term ``uranium byproduct material or tailings'' more broadly defines 
the materials that are subject to Subpart W.
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    Uranium recovery and processing currently occurs by one of three 
methods: (1) Conventional milling; (2) in-situ leach (ISL); and (3) 
heap leach. A conventional uranium mill is a chemical plant that 
extracts uranium from ore that has typically been obtained from an 
underground or open-pit mine. The ore is crushed and the uranium 
leached using chemical solutions, concentrated into uranium oxide 
(U3O8 or ``yellowcake''), and transported to a 
uranium conversion facility to begin the processing into fuel for 
nuclear reactors. Solid and liquid wastes produced during this process 
are called uranium byproduct material or tailings. Uranium byproduct 
material or tailings contains residual uranium, radium and heavy 
metals. Radon-222 is generated by the decay of radium-226. As defined 
in this final rule, conventional impoundments are used to manage the 
mostly solid wastes from processing. Non-conventional impoundments, 
also known as evaporation or holding ponds, are used to manage process 
liquids and effluents. Non-conventional impoundments may accumulate 
sediments at the bottom as solids contained in the liquids settle out. 
Conventional impoundments are permanent structures that require long-
term stewardship. Non-conventional impoundments are typically removed 
at facility closure and often placed into conventional impoundments for 
disposal. Non-conventional impoundments are sometimes also designed to 
be used as conventional impoundments as needed.
    ISL is often used when a uranium ore body is in a formation through 
which ground water flows. A liquid solution containing chemicals can be 
injected into the formation to mobilize the uranium into solution, 
which is then recovered and processed. Process liquids and effluents 
from ISL are managed in non-conventional impoundments. ISL is now the 
predominant form of uranium recovery in the United States.
    Heap leaching is a method of processing that is expected to be used 
for low-grade ore or in other situations where it is economically 
favorable. During heap leaching a pile of ore is sprayed with a 
chemical solution and uranium leaches into solution. The uranium 
solution is collected at the bottom of the pile and further processed. 
At the end of processing, the heap leach pile may be closed in place 
(typically by being covered), or removed and placed in a conventional 
impoundment. Process liquids and effluents are managed in non-
conventional impoundments. At the time of this rulemaking, there are no 
heap leach facilities in the United States, although one such facility 
is planned.
    There is currently one operating conventional mill in the United 
States, the White Mesa Mill in Utah. Two other conventional mills 
remain on standby, the Shootaring Canyon Mill in Utah and the 
Sweetwater Mill in Wyoming. There are six operating ISL facilities: 
Crow Butte in Nebraska; Smith Ranch, Lost Creek, Nichols Ranch, Willow 
Creek (which includes the Irigary and Christensen Ranch wellfields) and 
Ross CPP, all in Wyoming. Four other ISL facilities have operated and 
are now in standby. They are Alta Mesa, Kingsville Dome,\2\ Rosita and 
Hobson/La Palangana, all located in Texas. These facilities are subject 
to the requirements of Subpart W. There are no heap leach facilities 
operating or on standby. Future heap leach facilities, as well as 
conventional mills and ISL facilities that have been or are being 
licensed, will be subject to Subpart W when they begin operating.
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    \2\ Operating permits at the Kingsville Dome facility have 
lapsed and may not be renewed; however, because there are still 
uranium resources that could be exploited, Kingsville Dome is 
considered to be on standby for purposes of this discussion.
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    Subpart W was initially promulgated in 1986 and amended pursuant to 
a voluntary remand in 1989. For CAA section 112 standards that were in 
effect before November 15, 1990, CAA section 112(q)(1) requires the EPA 
to review, and, if appropriate, revise such standards to comply with 
the requirements of subsection (d). As a result of this review, we are 
promulgating this final rule pursuant to

[[Page 5144]]

CAA sections 112(q) and 112(d) and setting standards that comply with 
the requirements of CAA section 112(d)(5). CAA section 112(d)(5) 
addresses standards for area sources and provides that section 112(d) 
standards for area sources may provide for the use of GACT by the 
affected area sources.
    Subpart W regulates facilities and materials that are also 
regulated under the authority of the Uranium Mill Tailings Radiation 
Control Act of 1978 (UMTRCA). UMTRCA directed the EPA to establish 
standards of general application to protect public health, safety and 
the environment from hazards associated with wastes from extraction or 
concentration of uranium or thorium. The Nuclear Regulatory Commission 
(NRC) implements and enforces the EPA's standards through its licensing 
and regulatory program. By establishing requirements to control radon 
emissions from uranium byproduct material or tailings during the 
facility's operational period, Subpart W supports and works in harmony 
with the NRC's UMTRCA-based provisions that limit radon concentrations 
at the site boundary.
2. Provisions of the 1989 Rule
    When promulgated in 1989, Subpart W established monitoring 
requirements and work practices as methods to control radon emissions 
from impoundments used to manage uranium byproduct material or tailings 
(51 FR 51654, December 15, 1989). Existing impoundments (those 
operating as of December 15, 1989) were required to comply with a radon 
flux standard of 20 pCi/m\2\-sec, monitored using Method 115. New 
impoundments built after December 15, 1989 were required to be operated 
in accordance with the provisions of 40 CFR 192.32(a) and be designed 
to meet one of two work practices:
     Phased disposal in impoundments no larger than 40 acres in 
area, with no more than two such impoundments operating at any one 
time; or
     Continuous disposal of tailings such that tailings are 
dewatered and immediately disposed with no more than 10 acres of 
tailings exposed at any one time.
    All impoundments were required to be operated to comply with the 
requirements of 40 CFR 192.32(a),\3\ notwithstanding the exemption in 
Sec.  192.32(a)(1) for impoundments constructed prior to the 
promulgation of 40 CFR part 192. This provision was incorporated to 
ensure that older impoundments were equipped with liners capable of 
retaining liquids within the impoundment and monitoring systems capable 
of detecting leakages. Leaks could allow the contents of the 
impoundment to dry out and increase radon emissions. As originally 
promulgated in 1986, Subpart W envisioned that older impoundments would 
not be in use beyond December 31, 1992 unless granted an exemption or 
extension. Such impoundments were not required to comply with the 
provisions of 40 CFR 192.32(a). The 1989 rulemaking eliminated the 
prohibition on using existing impoundments beyond December 31, 1992 and 
required older impoundments to comply with the requirements at 40 CFR 
192.32(a) (51 FR 34066, September 24, 1986 and 54 FR 51680, December 
15, 1989).
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    \3\ 40 CFR 192.32(a) includes six elements, which apply during 
processing and prior to the end of the closure period: (1) 
Construction of impoundments in conformance with the requirements of 
40 CFR 264.221; (2) conformance to the groundwater protection 
standards in 40 CFR 264.92 and related sections; (3) placement of a 
permanent radon barrier on nonoperational impoundments; (4) 
demonstration that the permanent radon barrier limits radon releases 
to no greater than 20 pCi/m\2\-sec; (5) conformance to the 
requirements of 40 CFR part 190 and 40 CFR part 440; and (6) 
maintenance by NRC of public doses from radon emissions as far below 
the Federal Radiation Protection Guidance as practicable. Only Sec.  
192.32(a)(1) is directly relevant to the goals of Subpart W, which 
in turn facilitate NRC in achieving Sec.  192.32(a)(6).
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3. Provisions of the Final Rule
    This final rule defines and establishes GACT-based standards for 
conventional and non-conventional impoundments and heap leach piles; in 
doing so, the final rule clarifies the applicability of the 1989 rule 
to these different types of units and distinguishes among them. The 
final rule retains the radon flux standard and monitoring requirements 
for conventional impoundments in existence on December 15, 1989, and 
retains the provision that extended the construction requirements in 40 
CFR 192.32(a)(1) to these conventional impoundments. The final rule 
also formalizes the 1989 management practices as GACT-based standards 
for conventional impoundments constructed after December 15, 1989, with 
limited changes to the 1989 standard--the final rule focuses the cross-
reference regarding the impoundment construction requirements to 40 CFR 
192.32(a)(1), instead of a more broad reference to 40 CFR 192.32(a) and 
removes the phrase ``as determined by the Nuclear Regulatory 
Commission.'' In addition, the final rule establishes GACT-based 
standards for non-conventional impoundments and heap leach piles, as 
follows:
     Non-conventional impoundments must maintain solid 
materials in a saturated condition, with no solid materials visible 
above the level of liquid in the impoundment;
     Heap leach piles that have completed their operational 
life but not yet entered closure are limited to no more than two such 
piles with an area no greater than 40 acres each; and
     Conformance to the construction requirements in 40 CFR 
192.32(a)(1).
    The final rule changes some existing definitions and adds several 
new definitions. The amended definition of ``operation'' is finalized 
as proposed. The definitions of ``continuous disposal,'' ``dewatered,'' 
``existing impoundment,'' and ``phased disposal'' are amended to 
conform to the amended definition of ``operation.'' New definitions of 
``standby,'' ``conventional impoundment,'' ``non-conventional 
impoundment,'' ``heap leach pile,'' ``heap leach pile operational 
life,'' and ``uranium recovery facility'' are also being finalized as 
proposed. New definitions of ``final closure'' and ``reclamation plan'' 
are added to the final rule to clarify when Subpart W no longer applies 
to an impoundment or heap leach pile.
4. Key Changes to the Proposal
    The proposed rule contained several provisions that are modified in 
the final rule in response to public comments. We proposed to eliminate 
the radon flux standard and monitoring requirement for impoundments in 
existence on December 15, 1989. We believed this was appropriate based 
on information that indicated that the remaining impoundments in this 
category could comply with the GACT-based management practices. 
Information received through public comments demonstrated that the 
assumptions that supported our proposal were not correct and also that 
the pre-1989 unit that was expected to close (Cell 3 at the White Mesa 
Mill) remains open. Therefore, the final rule retains the radon flux 
standard and monitoring requirement for conventional impoundments in 
existence on December 15, 1989.
    We proposed that non-conventional impoundments maintain one meter 
of liquid above any solid materials in the impoundment. Our analyses 
indicate that liquids effectively attenuate radon emissions, and that 
one meter of liquid would reduce the radon emissions by greater than 
99%, to a level nearly indistinguishable from background. Based on 
public comment regarding feasibility and cost associated with the

[[Page 5145]]

water demand to maintain the liquid level in the impoundment, the final 
rule requires only that solid materials remain saturated. Saturation 
will effectively reduce radon emissions by approximately 95% compared 
to dry uranium byproduct material or tailing. The water demand to 
maintain saturation should also be considerably reduced compared to the 
proposal.
    We proposed that heap leach piles be regulated under Subpart W from 
the time they begin processing (i.e., at the time the leaching solution 
is first applied), because uranium byproduct material or tailings 
begins to be generated at that time. We proposed they be limited in 
size (40 acres) and number (no more than two operating at any one 
time), and maintain a 30% moisture content to reduce radon emissions. 
Based on public comment, the final rule provides that heap leach piles 
become subject to Subpart W once they have finished their operational 
life, when their sole purpose is to manage uranium byproduct material 
or tailings. As commenters pointed out, this is consistent with the 
approach we have taken for conventional mills, where waste material 
that has been separated from the recovered uranium has not been 
regulated under Subpart W until it leaves the processing unit and is 
deposited in an impoundment. Further, Subpart W will only apply to 
post-processing heap leach piles until they enter the closure process. 
The final rule retains the proposed area and number limitations on 
piles that are between processing and closure.
5. Economic Impacts
    This final rule will have limited economic impact. No new 
requirements are placed on conventional impoundments. Further, impacts 
associated with non-conventional impoundments and heap leach piles will 
be less than those estimated for the proposed rule. Operators of non-
conventional impoundments and heap leach piles will not incur 
additional cost related to liners, which are required by other 
regulations. Operators of non-conventional impoundments will be 
required to maintain liquids in the impoundment such that no solids are 
visible above the liquid level. In addition, operators of heap leach 
facilities can reduce the period of time they are subject to Subpart W 
and thus reduce compliance costs by expeditiously beginning the closure 
process after the operational life of the pile has ended, and we 
encourage timely closure in all cases.
    Table 1 presents a summary of the unit cost (per pound of 
U3O8) for implementing each GACT-based standard 
at each of the three types of uranium recovery facilities. In addition 
to presenting the GACT costs individually, Table 1 presents the total 
unit cost to implement all relevant GACT-based standards at each type 
of facility. Table 1 shows that a conventional mill will have both 
conventional and non-conventional impoundments, and be required to 
maintain saturation in the non-conventional impoundments.

                           Table 1--Final GACT-Based Standards Costs per Pound of U3O8
----------------------------------------------------------------------------------------------------------------
                                                                               Unit cost ($/lb U3O8)
                                                                 -----------------------------------------------
                                                                   Conventional
                                                                       mills      ISL facilities    Heap leach
----------------------------------------------------------------------------------------------------------------
GACT--Double Liners for Conventional Impoundments *.............           $1.04  ..............  ..............
GACT--Double Liners for Non-conventional Impoundments *.........            1.04            3.07            0.22
GACT--Maintaining Non-conventional Impoundment Sediments 100%              0.015           0.026          0.0013
 Saturated......................................................
GACT--Liners for Heap Leach Piles *.............................  ..............  ..............            2.01
GACTs--Total for All Four.......................................            2.09            3.09            2.24
Baseline Facility Costs ** (EIA Section 6.2)....................           55.18           51.31           45.06
----------------------------------------------------------------------------------------------------------------
* Liners required by 40 CFR part 192.
** Based on a price of U3O8 of $55/lb.

    Based on the information in Table 1, the four GACT-based standards 
represent about 4%, 6%, and 5% of the baseline cost (per pound of 
U3O8) at conventional, ISL, and heap leach 
uranium recovery facilities, respectively. The table shows that, at a 
market price of $55 per pound, the baseline facility costs for a 
conventional mill are greater than the market price of uranium. 
However, since the liner requirements would have to be met under 40 CFR 
part 192, these costs are not actually being imposed by Subpart W. The 
only cost associated with the final rule is the cost of maintaining 
saturation in the non-conventional impoundments, which is minimal.
6. Public Engagement
    During development of the proposed rule and throughout the public 
comment period, the EPA engaged with stakeholders and sought public 
input. Subsequent to beginning the rulemaking process, the EPA entered 
into a settlement agreement in August 2009 with Colorado Citizens 
Against Toxic Waste (CCAT) and Rocky Mountain Clean Air Action. As part 
of the settlement agreement, the EPA agreed to:
     Provide three public presentations and a national webinar 
on the rulemaking;
     Conduct quarterly stakeholder conference calls on the 
status of the rulemaking; and
     Create a public Web site and post non-privileged records.
    The EPA conducted public presentations in June 2009 in Ca[ntilde]on 
City, Colorado, near the Cotter Mill; in October 2009 in Rapid City, 
South Dakota, in conjunction with the Western Mining Action Network's 
semi-annual conference; and in May 2010 on lands of the Ute Mountain 
Ute Tribe in southeastern Utah, near the White Mesa Mill. The EPA also 
presented a national webinar in June 2010. Records of EPA's quarterly 
stakeholder calls and non-privileged records regarding this Subpart W 
rulemaking are available at the following public Web site: https://www.epa.gov/radiation/subpart-w-rulemaking-activity.
    In addition to the presentations specified in the settlement 
agreement, the EPA conducted presentations at numerous industry-
sponsored events, particularly the annual uranium recovery workshop 
sponsored by the NRC and the National Mining Association (NMA). 
Beginning in 2009, the EPA provided regular updates on the Subpart W 
rulemaking at these annual workshops. The EPA also provided a 
presentation for NMA

[[Page 5146]]

officials in October 2009 and participated in NRC's uranium recovery 
licensing workshop in January 2011.
    The EPA also actively sought interactions with tribal stakeholders. 
Several current or proposed uranium recovery facilities are of interest 
to tribes. The White Mesa Mill is located just north of Ute Mountain 
Ute lands in southeastern Utah. The Oglala Sioux Tribe has been active 
in the renewal of the operating license for the Crow Butte ISL facility 
in northwestern Nebraska and the initial licensing of the proposed 
Dewey-Burdock ISL facility in southwestern South Dakota. The Navajo 
Nation has been active in the development of proposed ISL facilities in 
New Mexico.
    The EPA conducted presentations at the Uranium Contamination 
Stakeholder Workshops in 2009 and 2010 in Gallup, New Mexico and Tuba 
City, Arizona, respectively. In addition to the presentations, the EPA 
also held discussions with representatives from the Navajo EPA and the 
Hopi Tribe. In June 2014, after the proposed rule was published, the 
EPA gave a presentation for the National Tribal Air Association (NTAA) 
on the monthly NTAA/EPA policy call.
    Concurrent with issuance of the 2014 proposed rule, the EPA sent 
letters to 53 tribal leaders offering consultation on the rule, 
consistent with the EPA's ``Policy on Consultation and Coordination 
with Indian Tribes.'' Consultation is a process of meaningful 
communication and coordination between the EPA and tribal officials 
prior to the EPA taking actions or implementing decisions that may 
affect tribes. The Ute Mountain Ute Tribe responded and requested a 
formal consultation. The consultation was held in July 2014 between 
officials of the EPA's Office of Radiation and Indoor Air in 
Washington, DC and officials from EPA Region 8 and the Tribe at Tribal 
headquarters in Towaoc, Colorado (Docket No. EPA-HQ-OAR-2008-0218-
0120).
    The EPA has also met with individual stakeholder groups. Prior to 
publication of the proposed rule, the EPA met with representatives from 
CCAT, Uranium Watch, and the Sheep Mountain Alliance. Following 
publication of the proposed rule, the EPA met with the Southern 
Environmental Law Center. Concurrent with public hearings in September 
2014, the EPA met with representatives from CCAT and the Energy 
Minerals Law Center. Following the public comment period, in November 
2014 the EPA met with representatives from Uranium Watch and the 
Information Network for Responsible Mining (INFORM).

B. Does this action apply to me?

    The regulated categories and entities potentially affected by the 
final standards are shown below in Table 2:

   Table 2--Industrial Source Categories Affected by This Final Action
------------------------------------------------------------------------
                                                  Examples of regulated
            Category             NAICS code \1\          entities
------------------------------------------------------------------------
Industry:
    Uranium Ores Mining and/or           212291  Area source facilities
     Beneficiating.                               that extract or
                                                  concentrate uranium
                                                  from any ore processed
                                                  primarily for its
                                                  source material
                                                  content.
    Leaching of Uranium, Radium          212291  Area source facilities
     or Vanadium Ores.                            that extract or
                                                  concentrate uranium
                                                  from any ore processed
                                                  primarily for its
                                                  source material
                                                  content.
------------------------------------------------------------------------
\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 
final action. If you have any questions regarding the applicability of 
this action to a particular entity, consult either the air permit 
authority for the entity or your EPA regional representative as listed 
in 40 CFR 61.04 of subpart A (General Provisions).

C. Where can I get a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
this final action will also be available on the Internet. Following 
signature, a copy of this final action will be posted at the following 
address: https://www.epa.gov/radiation/subpart-w-national-emission-standards-radon-emissions-operating-mill-tailings. Following 
publication in the Federal Register, the EPA will post the Federal 
Register version and key technical documents at this same Web site.

D. Judicial Review and Administrative Reconsideration

    Under CAA section 307(b)(1), judicial review of this final action 
is available only by filing a petition for review in the United States 
Court of Appeals for the District of Columbia Circuit by March 20, 
2017. Under CAA section 307(b)(2), the requirements established by this 
final rule may not be challenged separately in any civil or criminal 
proceedings brought by the EPA to enforce the requirements.
    Section 307(d)(7)(B) of the CAA further provides that ``[o]nly an 
objection to a rule or procedure which was raised with reasonable 
specificity during the period for public comment (including any public 
hearing) may be raised during judicial review.'' This section also 
provides a mechanism for the EPA to reconsider the rule ``[i]f the 
person raising an objection can demonstrate to the Administrator that 
it was impracticable to raise such objection within [the period for 
public comment] or if the grounds for such objection arose after the 
period for public comment (but within the time specified for judicial 
review) and if such objection is of central relevance to the outcome of 
the rule.'' Any person seeking to make such a demonstration should 
submit a Petition for Reconsideration to the Office of the 
Administrator, U.S. EPA, Room 3000, EPA WJC West Building, 1200 
Pennsylvania Ave. NW., Washington, DC 20460, with a copy to both the 
person(s) listed in the preceding FOR FURTHER INFORMATION CONTACT 
section, and the Associate General Counsel for the Air and Radiation 
Law Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200 
Pennsylvania Ave. NW., Washington, DC 20460.

II. Background

A. What is the Agency's legal authority for taking this action?

    Section 112(q)(1) of the Clean Air Act (CAA) requires that NESHAPs 
``in effect before the date of enactment of the Clean Air Act 
Amendments of 1990 [Nov. 15, 1990] . . . shall be reviewed and, if 
appropriate, revised, to comply with the requirements of subsection (d) 
of . . . section [112].'' The EPA promulgated 40 CFR part 61, subpart 
W, ``National Emission Standards for Radon Emissions from Operating 
Mill

[[Page 5147]]

Tailings,'' (Subpart W) on December 15, 1989.\4\ The EPA conducted this 
review of Subpart W under CAA section 112(q)(1).
---------------------------------------------------------------------------

    \4\ On April 26, 2007, Colorado Citizens Against Toxic Waste 
(CCAT) and Rocky Mountain Clean Air Action filed a lawsuit against 
EPA (EPA-HQ-OAR-2008-0218-0013) for EPA's alleged failure to review 
and, if appropriate, revise NESHAP Subpart W under CAA section 
112(q)(1). A settlement agreement was entered into between the 
parties in November 2009 (EPA-HQ-OAR-2008-0218-0020, 0021).
---------------------------------------------------------------------------

    Section 112(d) of the CAA requires the EPA to establish emission 
standards for major and area sources. A major source is any stationary 
source that emits or has the potential to emit 10 tons per year (tpy) 
or more of any single HAP or 25 tpy or more of any combination of HAPs. 
An area source is a stationary source of HAP that is not a major 
source. For operating uranium byproduct material or tailings 
impoundments, the HAP of concern is radon-222 (hereafter referred to as 
``radon'' or Rn-222). Radon emissions from operating uranium recovery 
facilities are far below the statutory thresholds \5\ and EPA has not 
set alternative criteria for identifying major sources of radionuclide 
emissions; thus, all sources regulated under Subpart W are area sources 
(EPA-HQ-OAR-2008-0218-0001, 0002). See Section IV.A.2.
---------------------------------------------------------------------------

    \5\ Annual emissions of radon from a 40-acre impoundment, 
assuming a radon flux of 20 pCi/m\2\-sec, can be calculated to be 
approximately 2.5 Ci. The specific activity of radon is about 
150,000 Ci/g. Reasonably anticipated emissions from sources subject 
to Subpart W do not approach the 10 tpy threshold established in CAA 
Sec.  112(a)(1) to define major sources.
---------------------------------------------------------------------------

    Section 112(q)(1) does not dictate how the EPA must conduct its 
review of those NESHAPs issued prior to 1990. Rather, it provides that 
the Agency must review, and, if appropriate, revise the standards to 
comply with the requirements of section 112(d). Determining what 
revisions, if any, are appropriate for these NESHAPs is best assessed 
through a case-by-case consideration of each NESHAP. As explained 
below, in this case, we have reviewed Subpart W and are revising the 
standards consistent with section 112(d)(5), which addresses standards 
for area sources. After our review, we determined it was appropriate to 
revise Subpart W to clarify the applicability of the rule to non-
conventional impoundments and heap leach piles and promulgate standards 
that are more appropriate for controlling radon emissions at those 
sources, consistent with the requirements of CAA section 112(d)(5). All 
units regulated by Subpart W are area sources and we determined that 
promulgating GACT-based standards under CAA section 112(d)(5) is 
appropriate for these sources.
    For area sources, the Administrator has the discretion under CAA 
section 112(d)(5) to set standards based on GACT in lieu of maximum 
achievable control technology (MACT) under sections 112(d)(2) and 
(d)(3), which is required for major sources. Under CAA section 
112(d)(5), the Administrator may elect to promulgate standards or 
requirements for area sources ``which provide for the use of generally 
available control technologies or management practices by such sources 
to reduce emissions of hazardous air pollutants.'' Consistent with 
section 112(d)(5), we are revising Subpart W to reflect GACT-based 
standards.

B. What source category is affected by the final rule?

    The source category regulated under Subpart W, first defined in 
1986, is facilities licensed to manage uranium byproduct material 
during and following the processing of uranium ores, commonly referred 
to as uranium mills and their associated tailings. Licenses are issued 
by the U.S. Nuclear Regulatory Commission (NRC) or NRC Agreement 
States. As promulgated in 1986 and 1989, Subpart W defines ``uranium 
byproduct material or tailings'' as ``the waste produced by the 
extraction or concentration of uranium from any ore processed primarily 
for its source material content.'' \6\ Neither of these definitions is 
affected by this action. For clarity, in this action we refer to this 
source category by the term ``uranium recovery facilities,'' and we are 
adding this phrase to the definitions section of the rule. Use of this 
term encompasses the existing universe of facilities whose HAP 
emissions are currently regulated under Subpart W. Uranium recovery 
facilities process uranium ore to extract uranium. The HAP emissions 
from any type of uranium recovery facility that manages uranium 
byproduct material or tailings are subject to regulation under Subpart 
W. This currently includes three types of uranium recovery facilities: 
(1) Conventional uranium mills; (2) ISL facilities; and (3) heap leach 
facilities. Subpart W requirements specifically apply to the affected 
sources at the uranium recovery facilities that are used to manage or 
contain the uranium byproduct material or tailings. Common names for 
these structures may include, but are not limited to, impoundments, 
tailings impoundments, tailings piles, evaporation or holding ponds, 
and heap leach piles. However, the name itself is not important for 
determining whether Subpart W requirements apply to that structure; 
rather, applicability is based on what these structures contain and the 
use of these structures to manage or contain uranium byproduct material 
or tailings.
---------------------------------------------------------------------------

    \6\ Pursuant to the Atomic Energy Act of 1954, as amended, the 
Nuclear Regulatory Commission defines ``source material'' 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'' (10 CFR 
20.1003). For a uranium recovery facility licensed by the Nuclear 
Regulatory Commission under 10 CFR part 40, ``byproduct material'' 
means the ``tailings or wastes produced by the extraction or 
concentration of uranium or thorium from ore processed primarily for 
its source material content, including discrete surface wastes 
resulting from uranium solution extraction processes'' (10 CFR 
20.1003 and 40.4).)
---------------------------------------------------------------------------

C. How does Subpart W regulate HAP emissions from the source category?

    Subpart W was initially promulgated on September 24, 1986 (51 FR 
34056) and amended pursuant to a voluntary remand on December 15, 1989 
(54 FR 51654). At the time of promulgation in the 1980s, the 
predominant form of uranium recovery was through the use of 
conventional mills. As promulgated in 1989, Subpart W contained two 
separate standards. The first standard applied to ``existing'' 
impoundments, i.e., those in existence and licensed by the NRC (or its 
Agreement States) on or prior to December 15, 1989. Owners or operators 
of existing tailings impoundments were required to ensure that 
emissions from those impoundments did not exceed a radon (Rn-222) flux 
standard of 20 picocuries per meter squared per second (pCi/m\2\-sec). 
As stated at the time of promulgation: ``This rule will have the 
practical effect of requiring the mill owners to keep their piles wet 
or covered'' (54 FR 51689). Keeping the piles (impoundments) wet or 
covered with soil would reduce radon emissions to a level that would 
meet the standard. This is still considered an effective method to 
reduce radon emissions at all uranium byproduct material or tailings 
impoundments.
    The method for monitoring for compliance with the radon flux 
standard was prescribed as Method 115, found at 40 CFR part 61, 
Appendix B. The owners or operators of existing impoundments were 
required to report to the EPA the results of the compliance testing for 
any calendar year by no later than March 31 of the following year.
    There is currently one operating mill with impoundments that pre-
date December 15, 1989, and two mills that are currently in standby 
mode. All of

[[Page 5148]]

these impoundments are subject to Subpart W until they begin closure.
    The second standard applied to ``new'' impoundments constructed 
after December 15, 1989. The requirements applicable to new 
impoundments were work practice standards that regulated either the 
size and number of impoundments, or the amount of tailings that may 
remain uncovered at any time. After December 15, 1989, ``no new 
tailings impoundment can be built unless it is designed, constructed 
and operated to meet one of the following two work practices:
    1. Phased disposal in lined tailings impoundments that are no more 
than 40 acres in area and meet the requirements of 40 CFR 192.32(a) as 
determined by the Nuclear Regulatory Commission. The owner or operator 
shall have no more than two impoundments, including existing 
impoundments, in operation at any one time.
    2. Continuous disposal of tailings such that tailings are dewatered 
and immediately disposed with no more than 10 acres uncovered at any 
time and operated in accordance with Sec.  192.32(a) as determined by 
the Nuclear Regulatory Commission.''
    The basis of the work practice standards was to (1) limit the size 
of the impoundment, which limits the radon source; or (2) use the 
continuous disposal system, which prohibits large accumulations of 
dewatered uncovered uranium byproduct material or tailings, limiting 
the amount of radon released.

D. What changes to Subpart W did we propose?

    Pursuant to CAA Section 112(d)(5), in the May 2, 2014 notice we 
proposed GACT-based standards for the affected sources at conventional 
uranium mills, ISL facilities and heap leach facilities. Subpart W has 
always applied to these sources; however, given the evolution of 
uranium recovery facilities over the last 20 years, we thought it 
appropriate to revise Subpart W to tailor the requirements of the 
NESHAP to the different types of facilities in existence at this time 
and reaffirm Subpart W's applicability to these facilities. For the 
conventional impoundments the GACT-based standards were based upon the 
requirements established in 1989. We also proposed to revise Subpart W 
to add appropriate definitions, standards and other requirements that 
are more applicable to HAP emissions at these different types of 
uranium recovery facilities. Specifically, we proposed to:
     Remove monitoring requirements for impoundments 
constructed prior to December 15, 1989 and to have these ``existing'' 
impoundments demonstrate compliance with the proposed GACT-based 
standards;
     clarify that any impoundment at a uranium recovery 
facility that contained uranium byproduct materials or tailings is 
regulated under Subpart W and subject to the liner requirements 
referenced at 40 CFR 192.32(a)(1), including ``evaporation'' or 
``holding'' ponds;
     establish as GACT-based standards that these ``non-
conventional'' or liquid-holding impoundments meet the design and 
construction requirements of 40 CFR 192.32(a)(1), with no size/area 
restriction or monitoring requirement, and that during the active life 
of the pond at least one meter of liquid be maintained in the pond;
     establish as GACT-based standards that heap leach piles 
meet the phased disposal management practice standard (which limits an 
owner/operator to no more than two operating heap leach piles of no 
more than 40 acres each at any time) and the design and construction 
requirements at 40 CFR 192.32(a)(1) as GACT-based standards, and 
maintain minimum moisture content of 30%;
     add a definition of ``standby'' to clarify the term and 
how it relates to the operational phase of an impoundment;
     amend the definition of ``operation'' of an impoundment so 
that it is clear when the owner or operator is subject to the 
requirements of Subpart W;
     add definitions of ``conventional impoundment,'' ``non-
conventional impoundment,'' ``heap leach pile,'' ``uranium recovery 
facility'' and ``heap leach pile operational life'' to be consistent 
with the GACT-based standards;
     determine whether Subpart W adequately addresses 
protection from extreme weather events;
     revise 40 CFR 61.252(b) and (c) to accurately reflect that 
it is only 40 CFR 192.32(a)(1) that is applicable to Subpart W; and
     remove the phrase ``as determined by the Nuclear 
Regulatory Commission'' in 40 CFR 61.252(b)(1) and (2).

E. Comments on the Proposed Rule

    The public comment period began on May 2, 2014 and was originally 
proposed to end on July 31, 2014. The comment period was extended by 
public request until October 29, 2014. We held two days of public 
hearings in Denver, CO on September 4 and 5, 2014. During the public 
comment period for the proposed rule, the EPA met with tribal leaders 
from the Ute Mountain Ute Tribe, consistent with the ``EPA Policy on 
Consultation and Coordination with Indian Tribes'' (http://www.epa.gov/tribal/forms/consultation-and-coordination-tribes). The consultation 
was held on July 10, 2014. The Tribe had numerous comments regarding 
the White Mesa uranium mill. Tribal land is several miles from the 
mill. The mill is the only operating conventional mill in the country, 
and the Tribe presented valuable information and comments for the 
rulemaking. The Tribe also raised enforcement issues that are concerns 
for the State of Utah and the EPA Region 8 office, but are not relevant 
to this rulemaking. The EPA has delegated to the State of Utah 
authority for implementation and enforcement of Subpart W (60 FR 13912, 
March 15, 1995).
    The EPA received approximately 45 separate sets of comments on the 
proposed rule, including multiple submittals by the same author(s). The 
comments range in size from one page to several hundred pages, and in 
many cases contain dozens of individual comments. All told the EPA 
identified over 4,000 individual comments. A mass mailer that contains 
over one thousand signatures is also in the docket for this rulemaking 
(Docket No. EPA-HQ-OAR-2008-0218). The docket also includes the 
transcripts of the two public hearings held in Denver, CO on September 
4 and 5, 2014. All of the comments received are in the docket for this 
rulemaking. All comments can be accessed electronically through the 
Federal Document Management System (FDMS), available at http://www.regulations.gov. This Web site provides instructions on how to 
access the electronic docket. Some submittals may be duplicated in 
FDMS, as a commenter may have used several methods to ensure the 
comments were received, such as statement at a public hearing, fax, 
email, U.S. mail, or directly through FDMS.
    There are two primary mechanisms by which we explain the issues 
raised in public comments and our reactions to them. First, we discuss 
broad or major comments in the following sections of this document. 
Second, we are including in the docket a document, accompanying this 
action, entitled ``Summary of Public Comments and Responses.'' The 
Response to Comments document addresses all other significant comments 
on the proposal. We gave all the relevant comments we received, whether 
written or oral, consideration in developing the final rule.

III. What final amendments are we issuing with this action?

    This action finalizes the EPA's determinations pursuant to its 
review of

[[Page 5149]]

Subpart W under CAA section 112(q)(1) to ``review, and if appropriate, 
revise'' NESHAPs promulgated prior to November 15, 1990. After review 
of the comments we determined that commenters provided reasons and 
presented information supporting revision to certain aspects of the 
proposed rule. In this section we describe the final amendments to 
Subpart W for this action and identify revisions made to the proposed 
rule in response to comments.

A. Application of Generally Available Control Technologies (GACT) to 
Uranium Recovery Facilities

    We determined that the management practices promulgated in 1989 for 
conventional impoundments constructed after December 15, 1989 remain 
suitable for controlling radon from uranium byproduct material or 
tailings. We also concluded that these management practices qualify as 
elements of GACT-based standards for these impoundments. We further 
determined that there are management practices which constitute 
generally available control technologies that could be applied to non-
conventional impoundments and heap leach piles. The final rule 
establishes the following elements as GACT-based standards for 
conventional impoundments constructed after December 15, 1989, non-
conventional impoundments and heap leach piles:
     Construction of all impoundments containing or managing 
uranium byproduct material in accordance with the requirements in 40 
CFR 192.32(a)(1);
     Operation of conventional impoundments in accordance with 
either the phased disposal or continuous disposal method;
     Operation of non-conventional impoundments such that solid 
materials in the impoundment are not visible above the liquid level, to 
be verified by daily visual inspection and documented by digital 
photograph no less frequently than weekly; and
     Maintenance of heap leach piles that have completed their 
operational life but have not yet entered closure in accordance with 
the phased disposal method (piles no larger than 40 acres in area and 
no more than two such piles at any time).
    For conventional impoundments constructed before December 15, 1989, 
we retained the radon flux standard originally promulgated in 1989, and 
retained the requirement that the impoundments comply with the 
construction requirements in 40 CFR 192.32(a)(1), notwithstanding the 
exemption in Sec.  192.32(a)(1) for impoundments constructed prior to 
the promulgation of 40 CFR part 192.

B. Definitions, References and Conforming Editorial Revisions

    We are making revisions to several existing definitions and 
references, deleting a phrase and providing several new definitions. 
These revisions are:
     The definition of ``operation'' is revised as proposed;
     The definitions of ``continuous disposal,'' ``dewatered,'' 
``existing impoundment,'' and ``phased disposal'' are revised to 
conform to the revised definition of ``operation'';
     Definitions of ``standby,'' ``conventional impoundment,'' 
``non-conventional impoundment,'' ``heap leach pile,'' ``uranium 
recovery facility,'' and ``heap leach pile operational life'' are added 
as proposed, with minor conforming changes;
     The reference in the 1989 rule at 40 CFR 61.252(b) and (c) 
is revised to 40 CFR 192.32(a)(1), as proposed, to clarify that the 
liner requirements are the portion of interest; as finalized, the 
reference to 40 CFR 192.32(a)(1) is included in Sec.  261.252(a)(2)(i), 
(a)(2)(ii), (b) & (c) and the reference at Sec.  61.252(c) in the 1989 
rule is incorporated into Sec.  61.252(a)(1) in the final rule;
     The phrase ``as determined by the Nuclear Regulatory 
Commission'' is eliminated from 40 CFR 61.252(b)(1) and (2), as 
proposed (Sec.  61.252(a)(2)(i) and (ii) in the final rule);
     The definition of ``final closure'' is added for 
completeness and clarity, in response to comments regarding the 
applicability of Subpart W; and
     The definition of ``reclamation plan'' is added to further 
clarify the concept of closure.

C. What are the recordkeeping, notification and reporting requirements?

    New and existing affected sources are required to comply with the 
existing requirements of the General Provisions (40 CFR part 61, 
subpart A). The General Provisions include specific requirements for 
notifications, recordkeeping and reporting, including provisions for 
notification of construction and/or modification and startup as 
required by 40 CFR 61.07, 61.08 and 61.09.
    We are also requiring that all affected sources maintain certain 
records pertaining to the design, construction and operation of 
conventional impoundments, non-conventional impoundments and heap leach 
piles. These records must be retained at the facility and contain 
information demonstrating that the impoundments and/or heap leach pile 
meet the requirements in 40 CFR 192.32(a)(1), including but not limited 
to, all tests performed that prove the liner is compatible with the 
material(s) being placed on the liner. For non-conventional 
impoundments, this requirement also includes records showing compliance 
with the requirement to maintain liquid in the impoundment such that 
solid materials are not visible above the liquid.\7\ Documents showing 
that the impoundments and/or heap leach pile meet the requirements in 
Sec.  192.32(a)(1) are already required as part of the pre-construction 
application submitted under 40 CFR 61.07, so these records should 
already be available. Written and other records showing compliance with 
the liquid requirement for non-conventional impoundments can be created 
during the daily inspections of the tailings and waste retention 
systems required by the NRC (and Agreement States) under the inspection 
requirements of 10 CFR part 40, Appendix A, Criterion 8A.
---------------------------------------------------------------------------

    \7\ The liquid requirement pertains to having the level of 
liquid cover any and all solid uranium byproduct material or 
tailings. We do not anticipate a large quantity of solid uranium 
byproduct material or tailings in these non-conventional 
impoundments (EPA-HQ-OAR- 2008-0218-0088).
---------------------------------------------------------------------------

    Because we are retaining the radon flux standard for conventional 
impoundments in existence on December 15, 1989, we are also retaining 
the associated reporting requirements at 40 CFR 61.254 and these units 
must also comply with the revised recordkeeping requirements at 40 CFR 
61.255, as applicable.
    Because we are promulgating new recordkeeping requirements for 
uranium recovery facilities, we are required by the Paperwork Reduction 
Act (PRA) to prepare an estimate of the burden of such record-keeping 
on the regulated entity, in both cost and hours necessary to comply 
with the requirements. We have submitted the Information Collection 
Request (ICR) containing this burden estimate and other supporting 
documentation to the Office of Management and Budget (OMB). See Section 
VII.B for more discussion of the PRA and ICR.
    We believe the record-keeping requirements promulgated today will 
not create a significant burden for operators of uranium recovery 
facilities. As described earlier, we are requiring retention of two 
types of records: (1) Records demonstrating that the impoundments and/
or heap leach pile meet the requirements in Sec.  192.32(a)(1) (e.g., 
the design and liner testing information); and (2) records showing that 
liquid is maintained to cover any

[[Page 5150]]

solid uranium byproduct material or tailings present in non-
conventional impoundments.
    Documents demonstrating that the affected sources comply with Sec.  
192.32(a)(1) requirements are necessary for the facility to obtain 
regulatory approval from the NRC (or an NRC Agreement State) and the 
EPA to construct and operate the affected sources (this includes any 
revisions during the period of operations). Therefore, these records 
will exist independent of Subpart W requirements and will not need to 
be continually updated as a result of this record-keeping requirement 
in Subpart W; however, we are including this record-keeping requirement 
in Subpart W to require that the records be maintained at the facility 
and available for inspection during its operational lifetime (in some 
cases the records might be stored at a location away from the facility, 
such as corporate offices). This might necessitate creating copies of 
the original records and providing a location for storing them at the 
facility.
    Keeping a record to provide confirmation that liquid is maintained 
above the solid uranium byproduct material or tailings present in non-
conventional impoundments should also be relatively straightforward. 
This would involve visual inspection and documentation, such as written 
notes and digital photographs with embedded date and time and other 
identifying metadata, using photographic capabilities that are readily 
available, such as smartphones or small digital cameras. As noted 
earlier, NRC and Agreement State licenses require operators to inspect 
the facility on a daily basis. Only minimal effort will be necessary to 
make observations of saturation and record the information in 
inspection log books that are already kept on site and available to 
inspectors. Inspections for saturation can occur during the daily 
inspections that are already required by NRC and Agreement States. The 
final rule requires that operators record written observations daily 
and collect photographic evidence of liquid depth no less frequently 
than weekly. Beginning on the effective date of this final rule, 
digital photographs are to be uploaded on at least a monthly basis to 
the EPA's Subpart W Impoundment Photographic Reporting (SWIPR) system. 
If that system is unavailable, digital photographs are to be retained 
by the facility and provided to the EPA or the authorized state upon 
request.
    The final rule also includes a definition of ``final closure'' that 
refers to notification by the facility owner/operator. Subpart W 
applies to operating sources used to manage uranium byproduct material 
or tailings. Sources cease to be operating when they enter the closure 
process. The definition of ``final closure'' in the final rule 
clarifies that closure does not begin until the owner or operator 
provides written notification to the EPA and the NRC that the 
impoundment or heap leach pile is no longer used for its operational 
purpose and is being managed under an approved reclamation plan for 
that impoundment or pile, or the facility closure plan. Such 
notifications should involve limited effort on the part of facility 
owners or operators. A reclamation plan is required by NRC regulation 
and is not a new requirement under Subpart W.
    We estimate the burden in hours and cost for uranium recovery 
facilities to comply with the proposed recordkeeping and notification 
requirements are as follows:

     Table 3--Burden Hours and Costs for Recordkeeping Requirements
                   [Annual figures except where noted]
------------------------------------------------------------------------
                Activity                       Hours           Costs
------------------------------------------------------------------------
Maintaining Records for the 40 CFR                  * 20        * $1,430
 192.32(a)(1) requirements..............
Verifying saturation for non-                        291          14,650
 conventional impoundments, including
 collecting and uploading digital
 photographs............................
------------------------------------------------------------------------
* These figures represent a one-time cost to the facility.

IV. What is the rationale for our final decisions and amendments to 
Subpart W?

A. Legal Authorities and GACT

    1. What is the legal authority for GACT based standards and 
management practices in the final rule?
    Section 112(q)(1) of the CAA requires that NESHAPs ``in effect 
before the date of enactment of the Clean Air Act Amendments of 1990 
[Nov. 15, 1990] . . . shall be reviewed and, if appropriate, revised, 
to comply with the requirements of subsection (d) of . . . section 
[112].'' The EPA promulgated 40 CFR part 61, subpart W, ``National 
Emission Standards for Radon Emissions from Operating Mill Tailings,'' 
(``Subpart W'') on December 15, 1989.\8\ The EPA conducted this review 
of Subpart W under CAA section 112(q)(1).
---------------------------------------------------------------------------

    \8\ On April 26, 2007, CCAT and Rocky Mountain Clean Air Action 
filed a lawsuit against the EPA (EPA-HQ-OAR-2008-0218-0013) for the 
EPA's alleged failure to review and, if appropriate, revise NESHAP 
Subpart W under CAA section 112(q)(1). A settlement agreement was 
entered into between the parties in November 2009 (EPA-HQ-OAR-2008-
0218-0020, -0021).
---------------------------------------------------------------------------

    Section 112(d) establishes the requirements for emission standards 
for HAP promulgated under section 112. It establishes different 
requirements for major sources and area sources. A major source is any 
stationary source that emits or has the potential to emit 10 tpy or 
more of any single HAP or 25 tpy or more of any combination of HAPs. An 
area source is a stationary source of HAP that is not a major source. 
See Sections II.B and IV.A.2 for discussion of area sources as they 
relate to Subpart W.
    Pursuant to CAA section 112(d), standards for major sources ``shall 
require the maximum degree of reduction in emissions of the hazardous 
air pollutants . . . that the Administrator . . . determines is 
achievable.'' For area sources, the Administrator has the discretion 
under CAA section 112(d)(5) to set standards based on GACT in lieu of 
MACT. Specifically, CAA section 112(d)(5) provides that the 
Administrator may elect to promulgate standards or requirements for 
area sources ``which provide for the use of generally available control 
technologies or management practices by such sources to reduce 
emissions of hazardous air pollutants.''
    Section 112(q)(1) does not dictate how the EPA must conduct its 
review of those NESHAPs issued prior to 1990. Rather, it provides that 
the Agency must review, and if appropriate, revise the standards to 
comply with the requirements of section 112(d). Determining what 
revisions, if any, are appropriate for these NESHAPs is best assessed 
through a case-by-case consideration of each NESHAP. In other 
rulemakings, the EPA has determined that GACT standards are appropriate 
for

[[Page 5151]]

a number of different area sources, including, for example, industrial, 
commercial and institutional boilers (promulgated at 40 CFR part 63, 
subpart JJJJJJ) and oil and natural gas production facilities 
(promulgated at 40 CFR part 63, subpart HH). Using a GACT evaluation, 
the EPA has historically established both emission standards and 
management practices, as appropriate.
    As explained below, in this case, we have reviewed Subpart W and 
are revising the standards consistent with section 112(d)(5), which 
addresses standards for area sources. After our review, we determined 
it was appropriate to revise Subpart W to clarify the applicability of 
the rule to non-conventional impoundments and heap leach piles and 
promulgate standards that are more appropriate for controlling radon 
emissions at those sources. All units regulated by Subpart W are area 
sources and we determined that promulgating GACT-based standards under 
CAA section 112(d)(5) is appropriate for these sources. Consistent with 
section 112(q)(1) we are revising Subpart W to comply with the 
requirements in section 112(d) relating to emission standards for area 
sources and are thus revising the Subpart W standards to reflect GACT-
based standards.
2. What key comments did we receive on our legal authorities and the 
GACT approach?
    We received several comments challenging our use of GACT for this 
rulemaking. Commenters specifically asserted that the EPA may not set 
GACT-based standards for sources subject to Subpart W and challenged 
our conclusion that facilities subject to Subpart W are area sources.
    Commenters further argued that the work practices instituted for 
conventional impoundments in 1989, which we are finalizing today as 
GACT-based standards, are contrary to CAA section 112(h), which allows 
the EPA to promulgate work practices in lieu of MACT standards only 
when ``it is not feasible in the judgment of the Administrator to 
prescribe or enforce an emission standard.''
    We summarize below a number of comments received on this topic and 
present our responses. Additional comment responses on this topic 
appear in the Response to Comments document in the docket for this 
rulemaking.
    Comment: A commenter argued that uranium recovery operations should 
be considered, by definition, major sources of hazardous air pollutants 
and should be subject to major source requirements. The commenter 
further stated that the EPA's document Background Information for 
Proposed Area Source Standards is misleading because it uses the 
standard major source threshold at CAA section 112(a)(1), that any 
stationary source that emits or has the potential to emit 10 tpy or 
more of any single HAP or 25 tpy or more of any combination of HAPs, to 
support its conclusion that uranium recovery facilities regulated under 
Subpart W are area sources. The commenter stated that radon is not 
measured in tpy and that the CAA section 112 threshold of 10 or 25 tpy 
was not intended to apply to radon or other radionuclides.
    Response: Under section 112(a)(1) of the CAA major sources are 
defined as stationary sources or groups of stationary sources that 
emit, or have the potential to emit, any single HAP at a rate of 10 tpy 
or more, or 25 tpy or more of any combination of HAP. An area source, 
in turn, is any stationary source of HAP that is not a major source. 
CAA section 112(a)(2). The statute also allows the EPA to establish 
lower thresholds, or for radionuclides to establish different criteria 
based on the characteristics of the air pollutant and relevant factors, 
but the statute is clear on its face that the EPA is not required to 
set alternative criteria. CAA section 112(a)(1). In the absence of 
alternative criteria, the statutory criteria of 10 tpy of a single HAP 
or 25 tpy of a combination of HAP applies, and any source that does not 
meet or exceed those thresholds is an area source. By allowing the EPA 
to set different criteria only for radionuclides, the statute 
implicitly recognizes that an alternative to the statutory thresholds 
based on tpy may be appropriate for sources of radionuclides. 
Nonetheless, the statute neither requires the EPA to set alternative 
criteria for defining major sources of radionuclides, nor obligates the 
EPA to designate any or all radionuclide sources as major sources. In 
sum, the statute explicitly leaves open the possibility that all 
sources of radionuclides will be regulated as area sources unless the 
EPA decides to establish alternate criteria. Moreover, even if the EPA 
had decided to set alternate criteria, nothing in the CAA would have 
required the EPA to establish criteria that would have the effect of 
making some sources that manage uranium byproduct material or tailings 
major sources of HAP. Thus, there is no basis for the commenter's 
assertion that uranium recovery operations should be considered, by 
definition, major sources of HAP.
    In addition, regulating sources that manage uranium byproduct 
material or tailings as area sources does not constrain the EPA's 
regulatory options. For area sources, the EPA can set GACT standards 
under CAA section 112(d)(5) or MACT standards under CAA section 
112(d)(2). EPA's decision to retain this flexibility by regulating 
these sources as area sources is reasonable and consistent with the 
discretion given to the EPA by the statutory text.
    It is also worth noting that, under Subpart W, radon emissions from 
sources that manage uranium byproduct material or tailings are 
regulated regardless of whether they qualify as major or area sources. 
For source categories not regulated before 1990, the EPA has discretion 
to decide whether to list and thus whether to regulate area sources. 
Radon emissions from uranium byproduct material or tailings, however, 
were regulated prior to 1990 and CAA section 112(q) explicitly provides 
that such standards remain in force and effect after the effective date 
of the 1990 CAA Amendments. The distinction between major and area 
sources thus does not affect whether sources subject to Subpart W are 
regulated under CAA section 112. Nothing in CAA section 112(q)(1) or 
CAA section 112(d) limits EPA's discretion to set standards under CAA 
section 112(d)(5), for sources regulated prior to the 1990 CAA 
Amendments whose emissions do not exceed the major source threshold 
established by Congress.
    Comment: Commenters stated that the EPA must establish a source 
category pursuant to CAA section 112(c)(1) before promulgating CAA 
section 112(d) standards. One of these commenters cites to a 2007 EPA 
rulemaking which stated that listing pursuant to section 112(c) is a 
critical aspect and a condition precedent to issuing CAA section 
112(d)(5) standards. Commenters also argued that the EPA must determine 
all HAPs present at uranium recovery facilities before the EPA can 
establish a source category, develop criteria to differentiate between 
major and area sources of radionuclides, and promulgate emission 
standards, whether MACT or GACT.
    Another commenter asserted that because CAA section 112(q) requires 
pre-1990 regulations to be reviewed and, if appropriate, revised in 
accordance with the requirements of subsection (d), the revision must 
comply with all applicable requirements in CAA section 112, including 
all parts of CAA section 112 enacted as part of the 1990 CAA 
Amendments.
    One commenter also argued that the EPA must establish a source 
category or subcategory before promulgating standards under CAA section 
112(d)(5) for facilities licensed to manage

[[Page 5152]]

uranium byproduct materials. The comments state that the EPA has not 
complied with the requirements of CAA section 112 and has not taken the 
requisite preliminary actions and evaluations to support establishing 
revised standards for uranium recovery facilities, specifically GACT. 
Another commenter stated that the EPA has no basis for setting GACT 
standards in lieu of MACT standards.
    Response: The EPA originally promulgated Subpart W in 1989, before 
Congress enacted the 1990 CAA Amendments. The 1990 Amendments 
introduced the requirement to list major and area sources of HAPs. See 
CAA sections 112(c)(1) & (c)(3), 42 U.S.C. 7412(c)(1) & (c)(3). The 
1990 Amendments also added CAA section 112(q), which explicitly 
provides that section 112 standards in effect prior to the date of 
enactment of the 1990 CAA Amendments shall remain in force and effect 
after that date. CAA section 112(q)(1) also provides that: ``Each 
[standard in effect before the enactment of the CAA Amendments of 1990] 
shall be reviewed and, if appropriate, revised to comply with the 
requirements of subsection (d) of this section . . .'' In sum, Congress 
clearly intended that (1) standards promulgated prior to 1990 remain in 
effect; and (2) the EPA may update the standards, as appropriate. 
However, there is no indication that Congress intended to require that 
the EPA go through the process of listing source categories that were 
subject to regulations prior to 1990 and thus, effectively already 
``listed.'' CAA section 112(c)(4) provides that, ``The Administrator 
may, in the Administrator's discretion, list any category or 
subcategory of source previously regulated under this section as in 
effect before November 15, 1990.'' The EPA reviewed Subpart W pursuant 
to section 112(q)(1) and has not listed uranium recovery operations 
pursuant to section 112(c).
    The EPA disagrees with the commenters' assertions that the EPA must 
list the regulated source category pursuant to section 112(c) before 
revising the existing Subpart W. Section 112(q)(1), on its face, does 
not require the EPA to list such sources pursuant to subsection (c) as 
part of a section 112(q) review. It does not contain any cross 
reference to the listing provisions of section 112(c). Instead, section 
112(q) requires revision, if appropriate, in accordance with subsection 
(d)--the subsection that governs standard setting under section 112. 
Moreover, section 112(c)(4) explicitly grants the Administrator 
discretion to decide whether or not to list categories and 
subcategories of sources regulated under section 112 prior to the 1990 
CAA Amendments. Thus, neither of the provisions addressing standards 
promulgated prior to the 1990 CAA Amendments, nor any other statutory 
provision, support the commenters' assertion that listing under section 
112(c) is a necessary part of a section 112(q) review.
    There is also no basis for commenters' statements that the EPA must 
determine all HAPs present at uranium recovery facilities and develop 
criteria to differentiate between major and area sources of 
radionuclides before it can promulgate emission standards, whether MACT 
or GACT. The EPA's task under section 112(q) is to review and, if 
appropriate, revise standards in effect before the date of enactment of 
the 1990 CAA Amendments. Prior to the 1990 CAA Amendments, section 112 
standards were promulgated for individual pollutants and Subpart W only 
establishes standards for radon resulting from management of uranium 
byproduct material or tailings at uranium recovery operations. The 
EPA's obligation under section 112(q) therefore is limited to reviewing 
and, if appropriate, revising standards for radon resulting from 
management of uranium byproduct material or tailings at uranium 
recovery operations. The statutorily required review does not encompass 
listing the source category under section 112(c) or evaluating HAPs not 
previously regulated under the subpart being reviewed. As explained in 
the previous response, the statute also does not require the EPA to set 
alternate criteria for distinguishing between major and area sources of 
radionuclides.
    The commenter's reliance on a 2007 rulemaking is misplaced. In that 
rulemaking, the EPA promulgated NESHAPs for the first time for the 
identified source categories. The present rulemaking is governed by CAA 
section 112(q)(1), which only requires that the review and revision 
comply with the standard setting requirements of subsection (d). As 
explained above, the section 112(q)(1) review does not require listing 
the source category under section 112(c). The 2007 rulemaking set new 
standards and was not subject to the narrow review requirements of CAA 
section 112(q)(1). Further, CAA section 112(c)(4) explicitly provides 
the EPA with discretion regarding whether to list source categories 
regulated prior to the 1990 CAA Amendments. CAA section 112(c)(4) 
applies to the sources subject to Subpart W but was not applicable to 
the sources impacted by the 2007 rulemaking. For these reasons, the 
statements made in the 2007 rulemaking are inapposite.
    The commenter's assertion that the EPA must revise Subpart W to 
comply with all provisions of section 112 is also based on an overly 
broad reading of CAA section 112(q)(1). The statute only instructs the 
EPA to ``review[ ] and, if appropriate, revise[ ], to comply with the 
requirements of subsection (d) of this section . . .'' It does not 
require the EPA to revise the pre-1990 rules to comply with every 
provision in the section 112 CAA Amendments of 1990. Indeed, to read 
section 112(q)(1) as requiring the EPA to revise the rules to comply 
with all provisions in section 112 would be to read the reference to 
subsection (d) out of the statute.
    Finally, listing a source category under section 112(c) is not a 
pre-requisite to establishing GACT standards for area sources as part 
of a section 112(q) review. As explained in the previous response, 
section 112(d)(5) allows the EPA to set GACT instead of MACT standards 
for area sources. Specifically, CAA section 112(d)(5) provides that 
with respect only to categories and subcategories of area sources 
listed pursuant to section 112(c), the Administrator may, in lieu of 
setting standards under sections 112(d)(2) and 112(f), decide to 
promulgate standards based on generally available control technologies. 
Such standards are commonly referred to as GACT standards.
    CAA section 112(d)(5) is ambiguous to the extent that it is not 
clear whether it provides that the EPA may set GACT standards ``only'' 
for ``area sources'' or whether it also prohibits the EPA from setting 
section 112(d)(5) GACT standards for area sources regulated under 
section 112 but not listed pursuant to section 112(c)--that is, area 
sources that are regulated pursuant to section 112 standards 
promulgated before the 1990 CAA Amendments but not added to the section 
112(c) list. For the reasons explained below, the EPA does not 
interpret section 112(d)(5) as limiting its discretion to promulgate 
GACT standards as part of a section 112(q) review simply because the 
area source category has not been added to the section 112(c) list.
    As an initial matter, the specific statutory provisions addressing 
section 112 standards that pre-dated the 1990 Amendments appear in 
sections 112(q)(1) and 112(c)(4). As discussed above, these provisions 
require the EPA to review and, if appropriate, revise such standards to 
comply with the requirements of subsection (d) and also establish that 
the EPA has discretion to decide whether or not to list source

[[Page 5153]]

categories under section 112(c). In the event of any conflict with 
other more general provisions in section 112, the more specific 
provisions of sections 112(q)(1) and 112(c)(4) govern.
    The general standard setting obligation in section 112(d)(1) also 
provides helpful context. Specifically, CAA section 112(d)(1) states 
that ``The Administrator shall promulgate regulations establishing 
emission standards for each category or subcategory of major sources 
and area sources of hazardous air pollutants listed for regulation 
pursuant to subsection (c) of this section . . .'' Section 112(d)(1) 
grants the EPA authority to set emission standards under both section 
112(d)(2) (MACT standards) and section 112(d)(5) (GACT standards). Like 
section 112(d)(5), it cross references the listing provision of 
subsection (c). Neither provision explicitly addresses how it applies 
in the context of a section 112(q) review. And neither provision 
explicitly overrides either the section 112(q) review requirements or 
the discretion granted to the Administrator under section 112(c)(4). 
Therefore, for standards promulgated prior to the 1990 CAA Amendments, 
it is reasonable for the EPA to interpret sections 112(d)(1) and (d)(5) 
to not require listing pursuant to Sec.  112(c) before the EPA can 
review the standards under section 112(q)(1) and, if appropriate, 
revise them to comply with subsection (d). In contrast, if the EPA were 
to take the approach suggested by commenters, and read the cross 
references to subsection (c) in sections 112(d)(1) and 112(d)(5) as a 
limitation on the EPA's authority under section 112(q) to revise 
standards to comply with subsection (d) it would be inconsistent with 
CAA sections 112(q)(1) and 112(c)(4).
    Given the statutory context outlined above, for this CAA section 
112(q)(1) review, it is reasonable for the EPA to interpret CAA section 
112(d)(5) as restricting the EPA's ability to set GACT standards to 
``only area sources,'' but not prohibiting the EPA from setting GACT 
standards as part of a section 112(q) review simply because the area 
source category is not listed pursuant to subsection (c).
    Comment: Several commenters argued that the EPA improperly proposed 
to promulgate design and work practice standards in lieu of emissions 
standards. Specifically, commenters stated that the EPA cannot 
promulgate design and work practice standards without the Administrator 
first making a finding pursuant to CAA section 112(h) that emission 
standards are not feasible. Commenters took the position that the EPA 
has not and cannot make a finding pursuant to CAA section 112(h) that 
radon emissions standards are not feasible at uranium recovery 
facilities. These and another commenter assert that the EPA has not and 
cannot make the ``not feasible'' showing, so the EPA must promulgate an 
emissions standard.
    One of these commenters stated that the EPA has no legal basis for 
the promulgation of a design, equipment, work practice, or operational 
standard, or combination thereof, in lieu of a radon emission standard, 
because design, equipment, work practice, or operational standards are 
meant to supplement, not replace, a standard that places specific 
numerical limitations on HAP emissions. The commenter also asserts that 
the EPA has no legal basis for eliminating the emission standard for 
existing mill tailings impoundments.
    The other commenter pointed to text from the legislative history of 
the 1990 CAA Amendments and stated that work practice standards must 
achieve the same or greater level of emissions reduction as a numerical 
emission standard. The commenter argues that radon emissions will be 
higher under the GACT standards than they would be under a numerical 
emission standard and therefore the EPA should promulgate an emission 
standard.
    Response: The EPA disagrees with these comments. The statute does 
not require the EPA to make a finding pursuant to CAA section 112(h) 
prior to promulgating management practices for area sources pursuant to 
section 112(d)(5). While section 112(d)(2) requires the EPA to make 
such a finding prior to setting work practice standards in lieu of an 
emission standard, section 112(d)(5) contains no such requirement.
    Instead, CAA section 112(d)(5) provides the EPA with discretion 
regarding the type of standards it sets for area sources by permitting 
the EPA to set standards or requirements ``which provide for the use of 
generally available control technologies or management practices'' (42 
U.S.C. 7412(d)(5)). The EPA determined that the management practices 
required in this final rule constitute generally available management 
practices and effectively control radon emissions from conventional 
impoundments constructed after December 15, 1989, non-conventional 
impoundments and heap leach piles.
    Because CAA section 112(d)(5) provides the EPA with the option of 
establishing management practices, the EPA was not required to make a 
showing under CAA section 112(h) that an emissions standard is not 
feasible before we set management practices. Further, CAA section 112 
does not provide that management practices must supplement emission 
standards; the EPA may set management practices to control emissions 
pursuant to CAA section 112(d)(5).
    With respect to existing conventional impoundments in existence on 
December 15, 1989, the EPA is retaining the emissions standard 
originally promulgated in 1989. During the comment period, the EPA 
learned that the information on which it relied when proposing to 
remove the emission standard requirement for existing conventional 
impoundments designed or constructed prior to December 15, 1989 was not 
accurate. Because the conventional impoundments in existence on 
December 15, 1989 are constructed in such a way that they are unable to 
comply with the standards being promulgated for conventional 
impoundments constructed after December 15, 1989, the EPA determined 
that it is appropriate to retain the emissions standard and monitoring 
requirement for conventional impoundments in existence on December 15, 
1989. Because these units have been subject to a radon flux standard of 
20 pCi/m\2\-sec since 1989, this method of compliance is generally 
available and effectively regulates radon emissions from these units.
    The EPA evaluated all types of units regulated by Subpart W: 
Conventional impoundments in existence as of December 15, 1989, 
conventional impoundments constructed after December 15, 1989, non-
conventional impoundments, and heap leach piles. Each type of unit has 
different characteristics. Also, not all units were subject to the same 
requirements at the time of their construction, and the feasibility of 
compliance with emissions standards and/or management practices also 
varies between types of units. The EPA took these variations into 
consideration when we conducted our GACT analysis for each type of 
unit. Because the three remaining conventional impoundments in 
existence as of December 15, 1989 were subject to different 
construction requirements than units constructed after that date, and 
are not amenable to the management practices established in 1989 for 
those newer units, different standards are appropriate.
    The legislative history language referenced by the commenter is 
concerned with the stringency of work practice standards promulgated 
under CAA section 112(h), when an emissions standard is not feasible. 
This passage of the legislative history is not discussing

[[Page 5154]]

the stringency of management practices promulgated under CAA section 
112(d)(5) and thus is not relevant. Further, the commenter's claim that 
radon emissions will be higher under the GACT-based standards than they 
would be under a numerical emission standard is speculative. The 
commenter has not shown that the management practices promulgated in 
Subpart W will not effectively result in the same emissions reductions 
that would be achieved if the EPA had set a MACT standard under CAA 
section 112(d)(2). The GACT-based standards finalized in the rule will 
effectively control radon emissions from uranium byproduct material or 
tailings.
    Comment: Several commenters challenged the EPA's authority to 
regulate impoundments associated with management of process liquids or 
effluents, referred to as non-conventional impoundments in the Subpart 
W rulemaking. One commenter submits that Subpart W does not apply to 
evaporation ponds at currently operating and future operating uranium 
recovery facilities, specifically in-situ facilities, because of the 
significant amount of process or waste water present. This and another 
commenter assert that evaporation ponds should not be regulated in 
Subpart W because the liquid cover substantially eliminates radon 
emissions. The second commenter further supports excluding evaporation 
ponds because the original 1989 rulemaking stated that science did not 
support the EPA exercising jurisdiction over fluid retention 
impoundments.
    This commenter similarly argues that the EPA has no legal or 
regulatory bases to apply Subpart W to evaporation ponds at uranium 
recovery facilities. Further, the commenter states that after 20 years 
of consistent interpretation that Subpart W is only applicable to 
uranium mill tailings impoundments, the EPA is now asserting that 
Subpart W applies to evaporation ponds at in-situ recovery and 
conventional mill tailings facilities. The commenter argues that the 
EPA's position is inconsistent with the language and the rulemaking 
history associated with Subpart W since the regulations discuss uranium 
mill tailings ``piles'' and the rulemaking record states that the radon 
cover requirements in Subpart W's work practice standards are not 
intended to apply to such fluid retention impoundments.
    The commenter also challenges that evaporation ponds are not 
covered by Subpart W because the specific examples in the regulations 
do not include evaporation ponds.
    Another commenter argues that the liquid impoundments should not be 
regulated as tailings impoundments and should not be subject to 40 CFR 
part 192.
    Alternatively, one commenter supported the EPA's confirmation that 
ISL facilities and liquid impoundments are subject to the EPA's CAA 
NESHAP jurisdiction. The commenter also stated that where the rule does 
not include emissions limits confirmed by monitoring and reporting 
requirements, the EPA has not carried out its CAA duty to minimize or 
eliminate radon emissions.
    Response: Non-conventional impoundments (which include evaporation 
and holding ponds) are associated with all types of uranium recovery 
facilities, but especially ISL facilities. Non-conventional 
impoundments receive liquids containing uranium byproduct material or 
tailings from conventional milling, ISL operations or heap leach piles 
and the uranium byproduct material or tailings may be suspended or 
dissolved in the liquids. Some portion of the material will precipitate 
out and settle on the bottom of the impoundment. In fact, the liquid 
itself constitutes uranium byproduct material or tailings because it is 
a waste from the concentration or extraction process.
    Commenters' arguments that the EPA lacks authority to regulate non-
conventional impoundments lack merit. As an initial matter, commenters 
do not and could not support their assertion that the EPA lacks legal 
authority to regulate these impoundments. Radionuclides, including 
radon, are listed as HAPs in CAA section 112(b)(1), and the EPA has 
authority under sections 112(d) and 112(q) to regulate radionuclide 
emissions from sources that manage uranium byproduct materials or 
tailings.
    In addition, commenters' alternate arguments, that these 
impoundments are not currently and should not be regulated by Subpart 
W, are incorrect. As promulgated in 1989, Subpart W requirements 
specifically apply to the structures at the uranium recovery facilities 
that are used to manage or contain the uranium byproduct material or 
tailings during and following the processing of uranium ores. 40 CFR 
61.250. Common names for these structures may include, but are not 
limited to, impoundments, tailings impoundments, evaporation or holding 
ponds, and heap leach piles. However, the name itself is not important 
for determining whether Subpart W requirements apply to that structure; 
rather, applicability is based on what these structures contain. 
Uranium byproduct material or tailings produced by ISL is covered by 
the definition of uranium byproduct material or tailings included in 
the 1989 Subpart W NESHAP, which is not altered by this final rule.
    The EPA understood that there was previously some confusion 
regarding the applicability of Subpart W to different units that manage 
uranium byproduct material or tailings, including impoundments and 
evaporation ponds at ISL facilities (non-conventional impoundments) and 
heap leach facilities. The EPA also acknowledges that the provisions of 
the 1989 rule applied imperfectly to these units. The industry is 
shifting toward ISL as the dominant method of uranium recovery and, 
while it is not expected to be as significant a source of radon 
emissions as conventional impoundments, it is reasonable for the EPA, 
as part of this section 112(q) review, to clarify that the standards in 
Subpart W apply to non-conventional impoundments. To eliminate any 
potential confusion, the final rule reaffirms that Subpart W continues 
to regulate radon emissions from all management of uranium byproduct 
material or tailings at uranium recovery facilities. Subpart W has 
always applied to these units; this final rule clarifies that 
applicability and confirms that these impoundments are covered by 
Subpart W by establishing management practices tailored to non-
conventional impoundments.\9\
---------------------------------------------------------------------------

    \9\ Note that the BID supporting the 1989 final rule stated: 
``The licensed uranium mill tailings source category comprises the 
tailings impoundments and evaporation ponds created by conventional 
acid or alkaline leach processes at uranium mills licensed by the 
Nuclear Regulatory Commission (NRC) or the Agreement States'' (BID 
Volume 2, Risk Assessments, EPA/520/1-89-006-1, page 9-1, emphasis 
added). The risk assessment evaluated the contribution of 
evaporation ponds to total radon emissions at some, but not all, of 
the operating and standby mills. If allowed to dry out, evaporation 
ponds could represent a non-negligible portion of the overall radon 
emissions subject to control under Subpart W. See Tables 9-2, 9-3, 
9-28.
---------------------------------------------------------------------------

    The EPA has authority to interpret its own regulations, Auer v. 
Robbins, 519 U.S. 452 (1992), and may clarify its interpretation when 
justified. In this rulemaking, the EPA did not revise its 
interpretation of Subpart W, rather we clarified the applicability of 
the regulations. Moreover, the EPA also provided notice and opportunity 
for comment on these clarifications.
    Commenters incorrectly state that evaporation ponds are not covered 
by Subpart W because evaporation ponds are not used as an example in 
the regulation. Similarly, commenters' claims that the radon cover 
requirements are not intended to apply

[[Page 5155]]

to fluid retention impoundments is inaccurate.\10\ As explained 
previously, the determining factor of whether evaporation ponds are 
subject to Subpart W and whether the radon cover requirements apply is 
whether the unit contains uranium byproduct material or tailings. Since 
promulgated in 1989, Subpart W has applied to facilities licensed to 
manage uranium byproduct material or tailings; units that manage 
uranium byproduct material or tailings must comply with the applicable 
GACT-based standard.
---------------------------------------------------------------------------

    \10\ In amending 40 CFR part 192 pursuant to an MOU with NRC, 
EPA stated the following in response to comments that evaporation 
ponds should remain open after emplacement of the final radon 
barrier: ``EPA reiterates that the Agency does not intend the 
expeditious radon cover requirements to extend to areas where 
evaporation ponds are located, even if on the pile itself, to the 
extent that such evaporation pond is deemed by the implementing 
agency (NRC or an affected Agreement State) to be an appropriate 
aspect to the overall remedial program for the particular site'' 
(emphasis added) (58 FR 60354, November 15, 1993).
---------------------------------------------------------------------------

    In addition, to the extent commenters are challenging the EPA's 
interpretation of the applicability provisions in 40 CFR part 192, such 
comments are beyond the scope of this rulemaking and the EPA has no 
obligation to respond. This rulemaking addresses only Subpart W. The 
EPA's May 2, 2014 proposal did not reopen or take comment on any 
aspects of part 192. The applicability provisions of part 192 appear at 
40 CFR 192.00. Subpart W does not expand the scope of applicability of 
part 192 as liners meeting the requirements at 40 CFR 192.32(a)(1) are 
already mandated by other regulations (79 FR 25407).
    In response to one commenter's argument that Subpart W should not 
regulate evaporation ponds at ISL facilities because of the amount of 
water present in the ponds, the EPA disagrees. While the EPA agrees 
that the presence of sufficient liquid significantly reduces the radon 
emissions, that is not itself a reason to exclude evaporation ponds 
from regulation as a pond may still contain uranium byproduct material 
or tailings, which have the potential to emit radon. As stated above, 
the presence of uranium byproduct material or tailings in the pond 
determines whether the pond is regulated by Subpart W. The management 
practices the EPA is promulgating in Subpart W ensure that the radon 
emissions are continuously effectively controlled. The EPA requires 
that owners and operators of non-conventional impoundments ensure that 
the uranium byproduct material or tailings remains saturated, meaning 
that the material is covered in liquid, which will effectively control 
radon emissions from these impoundments.
    The EPA acknowledges and appreciates the commenter's support of the 
EPA's clarification that uranium in-situ leach facilities are subject 
to Subpart W. The EPA's response to the comment regarding the 
requirement to establish emissions limits confirmed by monitoring and 
reporting requirements is contained in the response to the previous 
comment.
    Comment: Commenters questioned the appropriateness of including 
groundwater protection requirements in a NESHAP promulgated under the 
CAA since they do not affect air pollution. Further, one commenter 
added that the rule is unnecessary because it is designed to regulate 
HAPs yet it incorporates groundwater protection standards. The 
commenters stated that the additional requirements for fluid retention 
impoundments imposed by the imposition of 40 CFR 192.32(a)(1) and, by 
extension 40 CFR 264.221, are not justified.
    Both commenters asserted that if the NRC believed that the 
imposition of the part 192 requirements were justified, the NRC would 
have explicitly referenced 40 CFR 192.32(a)(1) and by extension 40 CFR 
264.221 in 10 CFR part 40 Appendix A, but it does not.
    Alternatively, another commenter asserted that the EPA cannot allow 
a situation where the reduction of radon emissions comes at the expense 
of increased pollution of the groundwater or surface water. The 
commenter is concerned that the rule works at cross-purpose with 40 CFR 
part 192.
    Response: The EPA may evaluate the non-air quality impacts of rules 
issued under CAA section 112. CAA section 112(d)(2) explicitly provides 
that the EPA has authority to consider non-air quality health and 
environmental impacts when promulgating standards under that section. 
For area sources, the EPA may promulgate standards under CAA section 
112(d)(5) in lieu of CAA section 112(d)(2). Since the CAA provides for 
the EPA to consider such impacts under CAA section 112(d)(2), it is 
reasonable for the EPA to consider such impacts under CAA section 
112(d)(5). Further, the CAA does not prohibit the EPA from considering 
non-air quality health and environmental impacts for CAA section 
112(d)(5) standards. Additionally, we believe the Legislative History 
of the CAA Amendments of 1990 provides for the EPA generally taking 
environmental protection into account when promulgating standards for 
area sources (Senate Report Number 101-228, December 20, 1989).
    Subpart W does not regulate groundwater or establish groundwater 
protection standards. Groundwater contamination is controlled by pre-
existing regulations prepared under the Uranium Mill Tailings Radiation 
Control Act of 1978 (UMTRCA). During Subpart W rule development, the 
EPA considered the other regulations that impact sources subject to 
Subpart W and understood that surface impoundments subject to Subpart W 
are also subject to the standards in 40 CFR part 192 and part 264, 
subpart K. The part 192 groundwater protection regulations and liner 
requirements independently apply to the units subject to Subpart W. 
Through part 192 and part 264, subpart K, requirements were already in 
place at the time Subpart W was originally promulgated to protect 
groundwater from sources that manage uranium byproduct material or 
tailings. As the EPA explained in 1986, ``potential effects of various 
alternatives on ground water were considered as part of the analysis of 
the impacts of this rule, since EPA has a responsibility to consider 
the impacts that its rules may have on the total environment. In part, 
this is done to ensure that regulations do not control pollution in one 
environmental medium only to degrade another'' (51 FR 34058-34059). See 
also 54 FR 51680.
    The EPA has considered the potential effects on groundwater from 
industry practices under this rule. The EPA also considered the 
separate, already existent, groundwater protection requirements when 
initially developing Subpart W. The EPA recognized that if water cover 
is maintained or expanded in order to limit radon emissions to the 
atmosphere, the potential for impacting groundwater increases because 
of the greater hydraulic head. It thus reasonably considered the extent 
to which existing requirements would limit potential groundwater 
impacts in determining reasonable management practices to limit radon 
emissions to the ambient air.
    Additionally, the liner requirements have a direct connection to 
the effectiveness of Subpart W in limiting radon emissions from uranium 
byproduct material or tailings. It is well established that moisture 
reduces the rate of radon emanation. An unlined or poorly lined 
impoundment is more likely to lose moisture through the bottom of the 
impoundment. This not only increases the potential for ground water 
contamination, but increases the potential for the uranium byproduct 
material or tailings in the impoundment to dry out, thereby increasing 
radon emissions. Thus, the liner requirements

[[Page 5156]]

boost the impoundment's ability to retain moisture and continue to 
control radon emissions. Because the liner requirements directly relate 
to the effectiveness of controlling radon emissions by retaining 
moisture and because the EPA considered the existing groundwater 
protection standards when evaluating the non-air environmental impact 
of using water to control air emissions, it was appropriate to 
acknowledge those standards and incorporate them into Subpart W. 
Further, nothing in this final action expands the applicability of 40 
CFR part 192 to sources that would not otherwise be covered by part 
192. See also Section IV.F.1.b.
    Comments on the NRC regulations contained in 10 CFR part 40 
Appendix A are beyond the scope of this rulemaking and, in any event, 
the regulations in 10 CFR part 40 Appendix A speak for themselves. In 
10 CFR part 40 Appendix A, the NRC references and recognizes that the 
standards promulgated by EPA in 40 CFR part 192 achieve the minimum 
level of stabilization and containment of the sites concerned and a 
level of protection for public health, safety, and the environment from 
radiological and nonradiological hazards associated with the sites. 
Additionally, 10 CFR part 40 Appendix A incorporates the basic 
groundwater protection standards imposed by the EPA in 40 CFR part 192 
which apply during operations and prior to the end of closure. 10 CFR 
part 40 Appendix A requires groundwater monitoring to comply with these 
standards.
    In response to the other commenter, the EPA considered the 
regulations that independently apply to sources subject to Subpart W. 
The EPA recognized that the scope of units required to operate with 
liners pursuant to part 192 is consistent with the Subpart W 
regulations. Subpart W does not lessen the effectiveness of part 192.
    Comment: Commenters concurred with the EPA's authority under 
Section 112 of the CAA to regulate radionuclide emissions at holding or 
evaporation ponds at conventional mills, at ISL facilities and at heap 
leach facilities. However, the commenters contend that the EPA should 
not only regulate uranium byproduct material or tailings in 
conventional impoundments, liquid effluent ponds, and heap leach piles, 
but should also regulate the large amounts of radon emitted from 
wellfields and other parts of ISL operations. One commenter used the 
Smith Ranch-Highland operation in Wyoming as an example.
    The commenters also advocated for the EPA expanding the scope of 
operations covered by Subpart W at heap leach facilities. Specifically, 
the commenters encouraged the EPA to regulate radon emissions from the 
time ore is placed on the pile, to the placement of a final radon 
barrier, including periods of standby, and time periods prior to and 
during the placement of lixiviant on a heap leach pile. The commenters 
also took the position that heap leach piles that are drying out should 
be subject to a radon emission standard.
    Response: The EPA acknowledges and appreciates the commenters' 
concurrence with the EPA's authority to regulate radionuclide emissions 
at holding or evaporation ponds at conventional mills, at ISL 
facilities and at heap leach facilities.
    When the EPA initially promulgated Subpart W in 1986, we identified 
radon as the radionuclide released to air that presented the highest 
risk at uranium recovery facilities and determined that units managing 
uranium byproduct material or tailings were the most significant source 
of radon emissions (51 FR 34056). Since 1986 and re-promulgation in 
1989, Subpart W has only regulated units that manage uranium byproduct 
material or tailings at uranium recovery facilities (40 CFR 61.250). 
Other potential emission points in these facilities were not previously 
the subject of Subpart W regulation and were not assessed for the 1989 
rulemaking. The EPA's CAA section 112(q) review of Subpart W was 
limited to the existing standard. Because Subpart W did not regulate 
other potential emission points, the EPA did not include any other 
potential emission points in its CAA section 112(q) review. In this 
final rule, the EPA continues to regulate the management of uranium 
byproduct material or tailings from conventional mills, from ISL 
facilities and from heap leach piles.
    With respect to regulation of heap leach piles, the EPA similarly 
retained the scope of Subpart W's applicability to sources that manage 
uranium byproduct material or tailings from heap leach operations. The 
EPA determined that, for purposes of Subpart W, while lixiviant is 
being sprayed on heap leach piles, the piles are part of the milling 
process rather than an impoundment whose function is to manage uranium 
byproduct material or tailings. The final rule does, however, cover the 
other impoundments used to manage the uranium byproduct material or 
tailings associated with the heap leaching operation and covers the 
heap leach pile during the period between the conclusion of processing 
and the day that final closure begins. See Section IV.D.
    Comment: Several commenters stated that the NRC has exclusive 
jurisdiction over the radiological and non-radiological aspects of 
uranium mill operations and the nuclear energy business and that the 
EPA lacks jurisdiction, particularly once the NRC promulgates 
conforming regulations. Commenters question the need to retain Subpart 
W at all, with one commenter contending that the existence of the 
Atomic Energy Act (AEA) makes Subpart W redundant and not necessary.
    One commenter takes the position that the EPA does not have 
authority to define when uranium recovery facilities are considered to 
be ``active'' or involved in ``operations.'' Instead, the commenter 
states that the NRC, not the EPA, has authority over decommissioning 
and decontamination of AEA-licensed source material recovery 
facilities, including the mill itself, site soil cleanup, final 
tailings stabilization, and groundwater restoration or corrective 
action. Further, the commenter states it is inefficient for uranium 
recovery operations to obtain two separate authorizations with 
essentially the same requirements for radon risk from fluid retention 
impoundments (i.e., the NRC operating license or license amendment and 
the EPA Subpart W construction approval), and that these duplicative 
requirements are inconsistent with the EPA's past efforts towards 
regulatory efficiency evidenced by the rescissions of 40 CFR part 61, 
subparts I and T.
    Another commenter states the Department of Energy also has 
authority to regulate this industry.
    Alternatively, some commenters supported the EPA's authority under 
the CAA to regulate HAPs, particularly radon, from uranium processing 
and do not believe that the CAA limits the EPA's regulatory authority 
with respect to 11e.(2) byproduct material \11\ at uranium recovery 
mill operations. Similarly, a commenter supported the proposed 
clarification to 40 CFR 61.252(b) (Sec.  61.252(a)(2) in the final 
rule) that the EPA, and not the NRC, is the regulatory agency 
administering the radon NESHAP requirements.
---------------------------------------------------------------------------

    \11\ UMTRCA amended the AEA definition of ``byproduct material'' 
by adding a second category. Section 11e.(2) byproduct material is 
``the tailings or wastes produced by the extraction or concentration 
of uranium or thorium from any ore processed primarily for its 
source material content.''
---------------------------------------------------------------------------

    Response: The EPA disagrees that it lacks authority to regulate, 
under CAA section 112, the radionuclide air

[[Page 5157]]

emissions of sources also regulated pursuant to the AEA by the NRC. The 
CAA lists radionuclides as a HAP under CAA section 112(b)(1), and 
section 112(q) explicitly retains standards such as Subpart W that were 
in effect before the date of enactment of the CAA Amendments of 1990. 
In addition, UMTRCA resolves this issue by quite explicitly stating 
that ``[n]othing in this chapter applicable to byproduct material . . . 
shall affect the authority of the [EPA] under the Clean Air Act of 
1970, as amended . . .'' (42 U.S.C. 2022(e)). The legislative history 
is similar: ``Authorities of the EPA under other laws would not be 
abridged by the new requirements'' (H. Rep. No. 1480, 95th Cong., 2d 
Sess. 6, p. 21). There is no indication that Congress intended UMTRCA 
to preempt the EPA's regulatory authority under the CAA; rather 
Congress expressly contemplated the EPA authority to simultaneously 
regulate under both legislative schemes (54 FR 51690-51691). Similarly, 
the EPA's regulation of the uranium processing industry works in 
concert with the AEA and the NRC's regulations.
    Comment: Some commenters stated that the NRC, not the EPA, has 
exclusive authority over the definition of 11e.(2) byproduct material, 
as well as the material itself. Commenters question the EPA's authority 
to promulgate a new definition for ``11e.(2) byproduct material'' or to 
equate the definition to the term ``mill tailings.'' The commenters 
opine that the EPA may not infringe on NRC authority by proposing an 
alternative definition of 11e.(2) byproduct material.
    One commenter also thinks that the EPA does not have statutory 
authority to define tailings as restoration fluid because that 
authority rests exclusively with the NRC.
    Response: The EPA disagrees with these comments. The EPA has 
authority to regulate radon emissions and this authority is not limited 
by the AEA or the NRC. Radionuclides, including radon, are listed HAPs 
in CAA section 112(b). The EPA regulated radon emissions from uranium 
byproduct material or tailings impoundments before the list of HAPs in 
CAA section 112(b) was added as part of the CAA Amendments of 1990 and 
CAA section 112(q) explicitly retains standards that were in effect 
before the 1990 CAA Amendments were enacted. The EPA's regulation of 
the uranium processing industry works in concert with the NRC's 
regulation. The EPA has authority to promulgate definitions under the 
CAA as it deems appropriate and is not limited to the AEA's definition 
of ``byproduct material'' or ``tailings,'' or the NRC's definition in 
10 CFR 40.4. The EPA first defined ``uranium byproduct material or 
tailings'' when promulgating Subpart W in 1986 (51 FR 34066, September 
24, 1986). The EPA's definition identifies the scope of material 
covered by the Subpart W regulations and does not preempt the NRC's AEA 
authority. The definition in Subpart W of uranium byproduct material or 
tailings is not substantially or meaningfully different from the NRC's 
definition of byproduct material in 10 CFR 40.4 or the definition of 
11e.(2) byproduct material and should not result in conflict. See also 
Section IV.F.2.
    Regarding the question of restoration fluids, we note that the 
designation of restoration fluids as ``waste produced by the extraction 
or concentration of uranium from any ore processed primarily for its 
source material content'' is consistent with the approach taken by the 
NRC. See Staff Requirements Memorandum--SECY-99-013, ``Recommendation 
on Ways to Improve the Efficiency of NRC Regulation at In Situ Leach 
Uranium Recovery Facilities,'' July 26, 2000.
    Comment: One commenter opposed comments of the regulated industry 
which argued that the EPA does not have authority to directly regulate 
radon emissions from uranium processing facilities. The commenter 
argued that the industry's arguments amount to an argument the EPA 
lacks authority over emissions from uranium mill tailings impoundments. 
The commenter opined that if industry wishes to remove a tailings 
facility from NESHAP regulation, it should submit a petition showing 
that radon emissions are not hazardous, but believes that such an 
effort would fail. The commenter continued that the EPA's proposed rule 
continues to recognize the health hazards of uncontrolled radon 
emissions from uranium mill tailings and the rulemaking record confirms 
that CAA NESHAP regulation is a necessary part of the EPA's role in 
regulating uranium mill tailings pursuant to its CAA and UMTRCA 
authorities.
    Numerous commenters supported the EPA's decision to regulate radon 
emissions from uranium mill facilities. Specifically, two commenters 
state that the EPA has authority to regulate all radon at mills and 
another commenter confirmed that the EPA has a role in regulating 
uranium mill tailings. A third commenter stated that the EPA has 
authority to conduct radon flux measurements.
    Response: The EPA acknowledges and appreciates these comments. The 
EPA agrees that it has authority under the CAA to regulate radionuclide 
emissions from uranium byproduct material or tailings as radionuclides, 
including radon, are listed HAPs in CAA section 112(b)(1). Data confirm 
conclusively that radon-222 emissions, ambient concentrations, 
bioaccumulation or deposition of radon and its decay products cause 
adverse effects on public health and the environment.

B. Retaining the Radon Flux Requirement for Impoundments in Existence 
on December 15, 1989

1. How did we address the radon flux requirement in the proposed and 
final rules?
    After reviewing stakeholder comments and verifying the information 
provided in them, we are not eliminating the radon flux standard of 20 
pCi/m\2\-sec for all impoundments in existence prior to or on December 
15, 1989. In the proposed rule, we provided information to show that 
the impoundments in existence prior to December 15, 1989 met the 
management practice requirements of impoundments constructed after that 
date (79 FR 25394). Since the conventional impoundments in existence 
prior to or on December 15, 1989 appeared to meet those management 
practice standards, we proposed that all conventional impoundments 
would be subject to the same management practices, regardless of the 
date of construction. We also proposed that all conventional 
impoundments (including those in existence prior to or on December 15, 
1989) must meet the requirements of one of the two management practice 
standards, and that the flux standard of 20 pCi/m\2\-sec would no 
longer be required for any impoundments.
    During the comment period we received information that led us to 
conclude that we had erred in stating an equivalency between the two 
types of impoundments. We originally stated that the Sweetwater and 
Shootaring impoundments had a double liner system equivalent to the 
impoundments designed after December 15, 1989. We were incorrect. 
Commenters \12\ showed that the liner systems at these two facilities 
were not double liners. Additionally, we were originally informed that 
Cell 3 at the White Mesa facility would be closed by 2014. In fact,

[[Page 5158]]

it has not.\13\ After reviewing the information obtained during the 
public comment period, we concluded that these impoundments do not meet 
the management practice standards we proposed for impoundments 
constructed after 1989. Our analysis also showed that the impoundments 
in existence on December 15, 1989 can monitor radon emissions to 
determine compliance with the existing 20 pCi/m\2\-sec standard. It is 
a generally available management practice standard that successfully 
limits radon emissions from these area sources, as provided for in CAA 
section 112(d)(5). Therefore, we decided to retain the radon flux 
standard (20 pCi/m\2\-sec) and monitoring requirement for conventional 
impoundments in existence on or before December 15, 1989 as the 
applicable GACT-based management practice. Because the 1989 rule 
required these impoundments to comply with the requirements at 40 CFR 
192.32(a)(1), we concluded that such a management practice is generally 
available and contributes to the control of radon emissions as 
described more fully in Section IV.A.2.
---------------------------------------------------------------------------

    \12\ EPA-HQ-OAR-2008-0218-0151, -0153, -0155, -0162. To be 
clear, our error was in believing that these impoundments were 
constructed in a manner that allowed them to meet the more stringent 
standards that were put in place after they were constructed. The 
standards applicable to these impoundments at the time of the 1989 
rulemaking did not require double liners.
    \13\ EPA-HQ-OAR-2008-0218-0151, -0170.
---------------------------------------------------------------------------

    Some commenters also supported requiring compliance with the flux 
standard for all impoundments, including those not now subject to it, 
but we have concluded that to be unnecessary if the owner/operator of 
an impoundment follows the design and other management practices 
outlined in the GACT-based standard because these measures are expected 
to effectively control total radon emissions.
2. What did our updated risk assessment tell us?
    As described in the preamble to the proposed rule, we updated the 
risk analysis we performed when we promulgated Subpart W in 1989 (79 FR 
25395, May 2, 2014). We performed a comparison between the 1989 risk 
assessment and current risk assessment approaches, focusing on the 
adequacy and the appropriateness of the original assessments.\14\
---------------------------------------------------------------------------

    \14\ ``Risk Assessment Revision for 40 CFR part 61 Subpart W: 
Task 4--Detailed Risk Estimates,'' prepared by S. Cohen & 
Associates, November 2011, Docket No. EPA-HQ-OAR-2008-0218-0078.
---------------------------------------------------------------------------

    Because we proposed to establish GACT-based standards to limit 
radon emissions from the management of uranium byproduct material or 
tailings at uranium recovery facilities, thereby eliminating any 
emissions standards and monitoring requirements, it was not necessary 
for us to update the risk assessment. GACT is not determined on the 
basis of risk. We conducted the analysis to inform ourselves regarding 
the continued protectiveness of the radon flux standard as we 
considered whether the proposed GACT approach could be extended to 
impoundments in existence on December 15, 1989. We concluded that, even 
using updated risk analysis procedures (i.e., using procedures updated 
from those used in the 1980s), the existing radon flux standard appears 
to be protective of the public health and the environment.
    The updated risk assessment involved evaluating exposures to off-
site (maximally exposed) individuals and populations from reported 
total site radon emissions at a number of uranium recovery facilities. 
In doing so, we found that the risks to individuals and populations 
were comparable to or lower than those estimated in the 1989 
rulemaking. The updated risk assessment employed the most recent risk 
factors for radon inhalation, which are age-averaged to incorporate the 
sensitivity of children to radiation. The factors used in the 1989 risk 
assessment were based on exposures to adults.
    This final rule retains the flux standard for conventional 
impoundments in existence on December 15, 1989. The updated risk 
assessment and our conclusion that the radon flux standard continues to 
be protective support our decision to retain the flux standard in the 
rule. The updated risk assessment is included in the Background 
Information Document (BID) for the final rule.
    In developing the risk assessment and BID, we also conducted 
environmental justice analyses for the immediate areas (i.e., counties) 
surrounding the existing and proposed uranium recovery facilities. For 
all of the sites considered together, the data did not reveal a 
disproportionately high incidence of minority populations being located 
near uranium recovery facilities. However, certain individual sites may 
be located in areas with high minority populations. Those sites would 
need to be evaluated during their individual licensing processes. The 
data also did not reveal disproportionately high incidence of low-
income populations being located near uranium recovery facilities. We 
also considered environmental justice analyses that were performed 
during the EPA's review of construction applications under 40 CFR 
61.08. These analyses were conducted by EPA Region 8 in connection with 
the Pi[ntilde]on Ridge Uranium Mill in Colorado and the Lost Creek ISL 
uranium project in Wyoming.
3. What key comments did we receive on the radon flux requirement?
    We received comments stating that the monitoring requirements for 
impoundments in existence on December 15, 1989 should be retained and 
that our proposal was based on faulty information. We also received 
comments recommending that monitoring be extended to all impoundments. 
Some commenters supported lowering the flux standard.
    Comment: Many commenters opposed the proposed elimination of the 
monitoring requirement for conventional impoundments in existence on 
December 15, 1989. Commenters expressed a general concern that no data 
would be available, but several also specifically questioned our 
rationale for doing so. They provided information indicating that the 
three ``existing'' (i.e., pre-1989) impoundments would not be able to 
meet the work practice standards (now designated as GACT). By contrast, 
a few commenters supported eliminating the monitoring requirement based 
on the effectiveness of the management practices.
    Response: We are retaining both the radon flux standard and the 
monitoring requirement for conventional impoundments in existence on 
December 15, 1989. Commenters provided information demonstrating that 
the conventional impoundments previously required to monitor radon 
emissions (i.e., Cell 3 at the White Mesa Mill and the impoundments at 
Shootaring Canyon and Sweetwater) are unable to meet the GACT-based 
standards. Although we agree with the other commenters that the GACT-
based standards are effective in limiting radon emissions, they were 
predicated on the impoundments meeting certain minimum requirements. 
Because comments included information demonstrating some conventional 
impoundments in existence on December 15, 1989 do not meet these 
minimum requirements or did not enter closure as the EPA expected, it 
is necessary and appropriate to retain the radon flux standard and 
monitoring requirement for these units.
    Comment: A number of commenters expressed the view that monitoring 
should not be limited to conventional impoundments constructed before 
December 15, 1989. They asserted that they have little confidence that 
the management practices in place for newer impoundments are 
effectively being implemented, and argue that it is not possible to 
verify their effectiveness without monitoring. The commenters

[[Page 5159]]

also expressed concern that impoundments that are drying out 
(``dewatering'') are emitting larger amounts of radon, and that without 
monitoring the operators are not compelled to provide additional soil 
cover.
    Response: The EPA reviewed the management practices prescribed for 
conventional impoundments constructed after December 15, 1989 and 
reaffirmed its determination that they effectively reduce radon 
emissions. The radon flux standard and monitoring requirement were 
instituted in the 1989 rulemaking to provide a means to control radon 
emissions from impoundments that were constructed and operated 
according to earlier industry practices. The EPA found that the 
management practices would represent a demonstrable improvement 
compared to those industry practices. The Agency has concluded that the 
appropriate action to satisfy its CAA review is to establish these 
management practices as GACT-based standards. We agree that operators 
need to take appropriate action to control radon during the period when 
the impoundment is operating, and not allow excessive drying during 
standby or other periods of limited activity. The management practices 
are intended to limit radon emissions. For conventional impoundments 
and heap leach piles, the management practices limit the exposed area 
and/or number of impoundments at a uranium recovery facility, which 
effectively limits the opportunity for radon emissions. For non-
conventional impoundments, ensuring that the material is saturated will 
limit radon emissions by approximately 95% compared to dry materials.
    Comment: Some commenters favored retaining the emissions standard 
for conventional impoundments constructed before December 15, 1989, but 
at a more stringent level. One commenter stated that a standard below 
10 pCi/m\2\-sec would be appropriate, and also that a review of current 
control technologies would support a standard of 1 to 5 pCi/m\2\-sec. 
Another commenter noted that the 1989 Background Information Document 
found that a 6 pCi/m\2\-sec standard was achievable and cost effective. 
This general view was supported by other commenters, with one stating 
that the 20 pCi/m\2\-sec standard was established ``for economic 
reasons.'' One commenter also expressed concern that the EPA did not 
evaluate monitoring methods other than Method 115, and specifically 
referred to the Landauer RadTrak.
    Response: Because the proposal involved eliminating all monitoring, 
the EPA did not evaluate the impacts of implementing other standards or 
monitoring methods. However, we did reaffirm that the 20 pCi/m\2\-sec 
standard remains protective, and we also find that Method 115 remains 
an appropriate method to measure radon emissions from conventional 
impoundments.\15\ We disagree with the characterization of the 20 pCi/
m\2\-sec flux standard as based on economics. As stated in the preamble 
to the 1989 final rule, when determining an ample margin of safety for 
the rule, ``As explained above, the risks from current emissions are 
very low. A NESHAP requiring that emissions from operating mill 
tailings piles limit their emissions to no more than 20 pCi/m\2\-sec 
represents current emissions. EPA has determined that the risks are low 
enough that it is unnecessary to reduce the already low risks from the 
tailings piles further'' (54 FR 51680, December 15, 1989). The update 
of the 1989 risk assessment conducted for this rulemaking confirms that 
the risk to public health from uranium byproduct material or tailings 
managed at operating uranium recovery facilities is comparable to, if 
not lower than, the level of risk considered presumptively acceptable 
in the 1989 rulemaking. See Section IV.B.2.
---------------------------------------------------------------------------

    \15\ ``Report on the Review of Method 115 to Monitor Radon 
Emissions From Uranium Tailings,'' prepared by S. Cohen & 
Associates, September 2008, Docket No. EPA-HQ-OAR-2008-0218-0122.
---------------------------------------------------------------------------

C. GACT for Conventional Impoundments Constructed After December 15, 
1989

1. How did we address conventional impoundments constructed after 
December 15, 1989 in the proposed and final rules?
    We proposed to designate the management practices promulgated in 
the 1989 rulemaking for impoundments constructed after December 15, 
1989 as GACT-based standards for all conventional impoundments. In 
doing so, we evaluated the reasoning used in the 1986 and 1989 Subpart 
W rulemakings to determine that the phased disposal and continuous 
disposal management practices protect public health with an ample 
margin of safety (54 FR 51681).
    We initially defined these two management practices because they 
provided a means for newly-designed impoundments to limit radon 
emissions, either by limiting the overall size of the impoundment or by 
limiting the area of dried (dewatered) uranium byproduct material or 
tailings that can be exposed at any time. We found the two management 
practices to improve performance (risk to exposed individuals and 
population) by approximately 35% to more than 50%, respectively, 
compared to earlier practices of constructing larger impoundments 
without limiting their number or the exposed area. The potential for 
larger impoundments or many smaller impoundments to remain uncovered 
and their radon emissions uncontrolled if bankruptcy prevented proper 
closure was considered to provide a further advantage to the two 
management practices (54 FR 51680).
    Owners and operators of uranium recovery facilities in the United 
States have all used the phased disposal method for management of 
uranium byproduct material or tailings in conventional impoundments, 
making it a generally available management practice to control radon 
emissions. We have found no reason to believe that this method is 
unworkable, unreasonably burdensome or ineffective in limiting radon 
emissions. Keeping the uranium byproduct material or tailings wet or 
partially covered, as is typical practice, further reduces radon 
emissions. These industry practices also clearly demonstrate that the 
phased disposal method is a generally available technology. In 
addition, while there has been no use of the continuous disposal method 
in the United States, it has been successfully employed in other 
countries, and was proposed for use by some U.S. companies in the 
1980s. Therefore, this final rule designates the phased disposal and 
continuous disposal methods as elements of GACT-based standards for 
conventional impoundments constructed after December 15, 1989. Because 
these impoundments are separately required to comply with the 
requirements at 40 CFR 192.32(a)(1), we concluded that such a 
management practice is generally available and contributes to the 
control of radon emissions as described more fully in Section IV.A.2. 
Conventional impoundments must also comply with the construction 
requirements in 40 CFR 192.32(a)(1).
2. What key comments did we receive on conventional impoundments 
constructed after December 15, 1989?
    We received some comments questioning the effectiveness of the 1989 
management practices and our decision to adopt those practices as GACT-
based standards. These commenters argued that there is no basis for 
concluding that these practices are effective in limiting radon 
emissions when no confirmatory monitoring has been done. They further

[[Page 5160]]

assert that the work practices were inadequate because practices that 
are actually effective in reducing radon emissions, such as maintaining 
a soil or water cover, were not elements of the 1989 work practices or 
the proposed GACT management practices.
    Comment: Several commenters believe our GACT standards are 
unsupported because there is no monitoring data to demonstrate the 
effectiveness of the measures for post-1989 impoundments. Commenters 
criticize the analysis of control technologies in the BID prepared to 
support the proposal as flawed and insufficient. One commenter states 
that limiting the size of the impoundment is not in itself an effective 
means to limit radon emissions without monitoring, reporting, and the 
requirement of liquid or soil application. This and another commenter 
also believe that any new impoundments should be required to use the 
continuous disposal method, as the commenters view the phased disposal 
method as ineffective in controlling radon emissions, particularly when 
using water cover. The first commenter further disputes the reliance on 
40 CFR 192.32(a)(1) as an effective control technology to limit radon 
emissions. Another commenter also suggests that the most effective 
control technology is an emissions limit coupled with monitoring, and 
believes the rule should be re-crafted along those lines.
    Commenters also asserted that we have not sufficiently examined 
other technologies employed either in other countries or in related 
industries. One commenter argues that other technologies (e.g., dry-
stack placement, paste tailings, solidification) may be superior to 
open-air storage and cover in conventional impoundments, but were not 
evaluated in the BID.
    Response: Our review under CAA section 112(q)(1) focused on the 
management practices applicable to post-1989 conventional impoundments 
(i.e., continuous or phased disposal). However, as noted in the 
proposal, we also considered control technologies employed at other 
facilities in the same industrial sector and internationally. We found 
that the continuous and phased disposal methods adequately control 
radon emissions and meet the requirements for GACT--these management 
practices are generally available and effectively prevent adverse 
health impacts from radon emissions. We recognize the commenter's 
position that the design and engineering requirement in 40 CFR 
192.32(a)(1) does not directly limit radon emissions. However, the 
design requirement serves two purposes. Retaining moisture or 
maintaining liquid levels within the impoundment does effectively 
inhibit radon flux while at the same time preventing releases to ground 
water. It is possible and important to achieve both goals.
    Regarding the area limitation, we disagree with the commenters. The 
focus of the 1989 analysis was on limiting the surface area from which 
radon would be emitted.\16\ Surface area is directly correlated with 
radon emanation--the smaller the surface, the lower the overall 
emissions, given similar materials. While the 1989 rulemaking clearly 
recognized that the use of soil cover or water are also effective in 
reducing radon emissions and were commonly employed by industry, the 
acceptability of the promulgated work practices was not predicated on 
those additional measures being employed, except to the extent that it 
was necessary to limit the exposed area when using the continuous 
disposal method.
---------------------------------------------------------------------------

    \16\ ``Either one of these technologies will ensure that future 
risks will be kept under control by assuring that only small amounts 
of tailings are uncovered at any time'' (54 FR 51681 (emphasis 
added)).
---------------------------------------------------------------------------

    Comment: Some commenters stated that the designation as an area 
source is not in itself sufficient to justify use of GACT. Commenters 
cite the legacy of contamination associated with the uranium industry 
as justifying the ``strongest preventive measures.'' Similarly, other 
commenters accuse the industry of ``cutting corners'' and believe GACT 
``runs counter to everything EPA knows'' about past practices. Another 
commenter argues that the Agency's ``discretion'' must be supported by 
full and complete explanation and justification. These and other 
commenters also believe the EPA has not sufficiently considered MACT 
approaches.
    Response: When setting standards, the EPA aims to ensure that the 
promulgated standards effectively protect against adverse environmental 
and health impacts, regardless of whether such standards are based on 
GACT or MACT. For area sources, the Administrator has the discretion 
under CAA section 112(d)(5) to set standards based on GACT in lieu of 
setting MACT standards under sections 112(d)(2) and (d)(3), which is 
required for major sources. See Section IV.A.2 for discussion of 
regulating these units as area sources. Under CAA section 112(d)(5), 
the Administrator may elect to promulgate standards or requirements for 
area sources ``which provide for the use of generally available control 
technologies or management practices by such sources to reduce 
emissions of hazardous air pollutants.'' Consistent with section 
112(d)(5), we are revising Subpart W to reflect GACT-based standards. 
Based on the EPA's evaluation of available information, the GACT-based 
approach in the final rule provides the necessary protections from 
management of uranium byproduct material or tailings. The emission 
standards and management practices established in Subpart W will 
appropriately reduce radon emissions from uranium recovery facilities.

D. GACT for Heap Leach Piles

1. How did we address heap leach piles in the proposed and final rules?
a. When are heap leach piles regulated under Subpart W?
    We proposed to regulate the heap leach pile from the moment that 
uranium begins leaching from the ore pile. This approach was based on 
the view that uranium byproduct material or tailings is produced the 
moment the lixiviant passes through on its first pass and uranium 
begins to be leached from the ore (79 FR 25403). At the point of 
uranium movement out of the heap, what remains is uranium byproduct 
material or tailings as defined by 40 CFR 61.251(g). In other words, 
what remains in the heap is the waste produced by the extraction or 
concentration of uranium from ore processed primarily for its source 
material content. The heap leach pile manages that uranium byproduct 
material or tailings, even as the pile is further leached to extract 
uranium. The proposal placed the emphasis on the presence of uranium 
byproduct material or tailings in the heap leach pile.
    We also requested comment on an alternative approach we described 
in the proposal (79 FR 25398). Under this approach, heap leach piles 
would not fall under Subpart W until after leaching is permanently 
discontinued. This approach is based on the view that, as long as the 
heap is being leached, the ore on the heap leach pad is being 
processed. While uranium byproduct material or tailings may exist in 
the heap, the heap does not become engaged in managing uranium 
byproduct material or tailings until leaching is permanently 
discontinued. This view places the emphasis on the continued extraction 
of uranium from the heap leach pile. Only after that extraction 
potential is exhausted, and only uranium byproduct material or tailings 
remains, would the pile fall under Subpart W.
    Many commenters (primarily those from industry) supported basing 
the

[[Page 5161]]

final rule on this alternative view. These commenters argued that the 
heap leaching cycle is essentially serving the same function as the 
successive leaching of uranium that occurs in the leach and counter 
current decantation circuits of a conventional mill, where the ore pulp 
is successively leached in a series of leach tanks and thickeners. The 
material does not become uranium byproduct material or tailings (i.e., 
waste) and fall under the requirements of Subpart W until it leaves the 
final thickener and is discharged to the tailings impoundment.
    Although we proposed to bring the heap under the jurisdiction of 
Subpart W based upon the presence of uranium byproduct material or 
tailings within the pile, after further consideration we find the 
commenters' reasoning compelling and more consistent with previous 
application of the rule. Subpart W has historically not regulated radon 
emissions from the milling or extraction process, even at the 
intermediate points where residuals from uranium extraction make up the 
bulk of the material being processed, which may be the situation as 
processing of the heap progresses. Subpart W has regulated only the 
disposition of the wastes at the end of the separations process. 
Consistent with this precedent, the heap leach pile is like a 
conventional impoundment and will be subject to Subpart W once uranium 
extraction is complete and only uranium byproduct material or tailings 
remains. Until that time, the heap is considered to be either an 
unprocessed ore pile or a uranium recovery facility. Thus, heap leach 
piles are regulated by Subpart W only during the period between the end 
of processing (i.e., after the pile's operational life) and the 
beginning of closure. As described in Section IV.F.1.a, and consistent 
with the requirements applicable to conventional and non-conventional 
impoundments, the final rule requires that operators provide written 
notification to the EPA and the NRC that the heap leach pile is being 
managed under an approved reclamation plan for that pile or the 
facility closure plan. Impoundments used to manage liquids resulting 
from the heap leach operation, to the extent they contain uranium 
byproduct material or tailings, are considered non-conventional 
impoundments subject to Subpart W, as defined in today's final rule.
    There is a significant aspect of heap leach pile management that is 
important to these regulations. Several commenters from industry stated 
that a heap leach pile, unlike a conventional impoundment, will 
immediately begin closure after processing has concluded (either 
closure in place, or possibly removal for placement in a conventional 
tailings impoundment). If that is the case, there will be no period 
when the heap is subject to the requirements of Subpart W. Because 
there are no heap leach facilities operating in the United States, we 
have no basis for disputing these statements of industry's intent. 
Nevertheless, we have concerns that these good intentions may prove 
insufficient to ensure that closure takes place as expeditiously as the 
commenters believe. There is some potential that heap leach piles will 
complete processing but not immediately enter closure. During such a 
period the owner or operator is only using the pile to manage uranium 
byproduct material or tailings, and the heap leach pile is then subject 
to the requirements of Subpart W. The specification in the final rule 
that final closure does not begin until the operator has provided a 
written notification to the EPA and the NRC will minimize the potential 
for confusion regarding the applicability of Subpart W. A further 
concern might be that operators continue ``processing'' the pile 
indefinitely, thereby postponing the costs associated with closure. 
This would be a matter for the NRC or NRC Agreement States to consider.
    We recognize that heap leach piles will emit radon while they are 
being processed. However, as explained above, Subpart W has 
traditionally been applied to uranium byproduct material or tailings 
after exiting the extraction process. Thus, Subpart W has not been 
applied to other sources of radon at uranium recovery facilities where 
wastes are present, such as material in thickeners or other processing 
units. The NRC, or NRC Agreement State, regulates the radionuclide 
emissions from all sources at a uranium recovery facility. The operator 
is required to report particulate radionuclide and Rn-222 
concentrations at the facility boundary. Thus, radon emissions from 
sources not covered under Subpart W, including those from the raw ore 
in heap leach piles or processed yellowcake, are captured by the NRC 
reporting requirements. However, we emphasize that the best way to 
control radon emissions from heap leach piles after they have completed 
processing is to expeditiously close them and install a permanent radon 
barrier.
b. Phased Disposal
    As described in the preceding section, after reviewing comments, we 
have decided to require that heap leach piles conform to the standards 
for other uranium recovery facility impoundments only during the period 
between processing (i.e., after the pile's operational life) and 
closure. Heap leach piles meeting this description will conform to the 
GACT-based standard of phased disposal (piles that are 40 acres or less 
in area, and no more than two in this status at any time) and follow 
the construction requirements of 40 CFR 192.32(a)(1). We note that 
piles that will close in place would separately be required by NRC or 
Agreement State license to meet the construction requirements.
    Since heap leach piles are in many ways similar to the design of 
conventional impoundments, the same combination of phased disposal 
management practices (limitation to no more than two heap leach piles 
that are no longer being processed but have not yet entered closure, 
each one no more than 40 acres in area) that limit radon emissions from 
conventional impoundments will also limit radon emissions from heap 
leach piles. Because this management practice is generally available 
for conventional impoundments, heap leach piles can control radon 
emissions through the same practice. We determined that phased disposal 
is a GACT-based management practice that will effectively limit radon 
emissions from these units. Use of the phased disposal management 
practice will limit the amount of exposed uranium byproduct material or 
tailings that can emit radon. Because these units will be separately 
required to comply with the requirements at 40 CFR 192.32(a)(1), we 
concluded that such a management practice is generally available and 
contributes to the control of radon emissions as described more fully 
in Section IV.A.2.
c. Regulating the Moisture Content of Heap Leach Piles
    The third issue we are addressing is the proposed requirement for 
heap leach piles to maintain a 30% moisture content. In the proposal we 
recognized that owners and operators of conventional impoundments also 
limit the amount of radon emitted by keeping the uranium byproduct 
material or tailings in the impoundments covered, either with soil or 
liquids (79 FR 25398). At the same time, we recognized that keeping the 
uranium byproduct material or tailings in the heap in a saturated or 
near-saturated state (in order to reduce radon emissions) is not a 
similarly practical solution. In the definitions at 40 CFR 61.251(c) we 
have defined ``dewatered'' tailings as those where the water content of 
the tailings does not

[[Page 5162]]

exceed 30% by weight. We proposed to require operating heaps to 
maintain moisture content of greater than 30% so that the uranium 
byproduct material or tailings in the heap is not allowed to become 
dewatered, which would allow more radon emissions. We specifically 
asked for comment on the amount of liquid that should be required in 
the heap, and whether the 30% figure was a realistic objective.
    After considering stakeholder comments and information, we conclude 
that it is physically impossible to maintain a 30% moisture content 
within the heap leach pile and have it remain stable.\17\ Calculations 
submitted by numerous commenters showed that maintaining a 30% moisture 
content across the heap leach pile would require the pile to be almost 
submerged. Further, such a condition would place a great amount of 
hydraulic head on the liner system, potentially causing failure. So, 
the final rule does not include the requirement to maintain 30% 
moisture content, even for the period between the end of processing and 
the beginning of closure, when the pile will be allowed to ``dry'' in 
preparation for placing a permanent radon barrier. We do encourage the 
NRC and facility operators to consider the appropriate use of soil and 
liquid to limit radon emissions from heap leach piles, as well as 
methods to reduce the potential for wind erosion (e.g., by spraying or 
covering the pile when not actively being leached). However, we 
emphasize that the best way to control radon emissions from heap leach 
piles after they have completed processing is to expeditiously close 
them and install a permanent radon barrier.
---------------------------------------------------------------------------

    \17\ EPA-HQ-OAR-2008-0218-0144, -0162, -0169, -0170.
---------------------------------------------------------------------------

2. What key comments did we receive on heap leach piles?
    Comments submitted on heap leach piles focused on the proposed 
approach to regulation and the proposed requirement to maintain a 30% 
moisture content.
    Comment: Most commenters on this topic disagreed with our proposal 
to regulate heap leach piles under Subpart W while they are being 
processed. These commenters expressed the view that material in the 
heap leach pile does not become uranium byproduct material or tailings 
until processing is complete, including a final rinse. As stated by one 
commenter, ``Heap leaching is part of the milling process, and the 
proposed rules would interfere with such processing operations.'' The 
commenter believes that, in essence, the heap leach pile is analogous 
to the conventional mill, which we have not previously proposed to 
regulate under Subpart W.
    Further, several of these commenters stated that heap leach piles 
will immediately enter into closure upon the cessation of processing, 
so there is no period when they are ``operating'' simply as uranium 
byproduct material or tailings management units. As a result, they see 
no time at which Subpart W can apply to heap leach piles.
    Some commenters raised the distinction between ``close in place'' 
piles and ``on-off'' piles. Commenters explain that the latter 
operations involve the removal of the processed heap and placement in a 
conventional impoundment. In this case, the commenters agree that the 
uranium byproduct material or tailings from the heap, and the 
impoundment into which it is placed, would be subject to Subpart W.
    Response: The final rule does not include requirements related to 
heap leach piles undergoing processing. We acknowledge the comments 
that indicate that uranium byproduct material or tailings is generated 
once processing begins. To ensure that heap leach piles are regulated 
consistent with other units subject to Subpart W, we conclude that the 
heap leach pile is, for purposes of Subpart W, more appropriately 
considered part of the milling process than as an impoundment whose 
function is to manage uranium byproduct material or tailings. In other 
words, while the pile may contain uranium byproduct material or 
tailings, the pile itself is the ore from which uranium is being 
extracted, and does not become a waste until that process is completed. 
The rule does, however, cover the other impoundments used to manage the 
uranium byproduct material or tailings associated with the heap 
leaching operation.
    We appreciate the commenter's description of the ``on-off'' heap 
leach piles and agree that if a processed heap is removed and placed in 
a conventional impoundment, that impoundment is subject to Subpart W.
    We emphasize the importance of closing piles ``as expeditiously as 
practicable considering technological feasibility'' once processing 
concludes. Industry commenters provided assurances that there would be 
no untoward delay in beginning the closure process. We encourage NRC to 
ensure that this is the case. Closure is a more comprehensive system to 
assure that emissions are minimized for the long term. Once processing 
has ended, the heap leach pile serves only as a uranium byproduct 
material or tailings management structure. Such a pile will be subject 
to Subpart W if the operator has not informed regulators that it is 
being managed under an approved reclamation plan. As set forth in the 
final rule, in such a situation, the phased disposal restrictions will 
apply (no more than two such piles at any time, with area no greater 
than 40 acres each). Heap leach piles subject to Subpart W must also 
comply with the construction requirements at 40 CFR 192.32(a)(1). 
Timely closure of heap leach piles will be better for public health 
than maintaining piles in an interim state in which they fall under 
Subpart W.
    Comment: Some comments supported our proposed approach, and 
recommended that we establish an emissions standard and monitoring 
requirements for heap leach piles. These commenters agree that, because 
uranium byproduct material or tailings is generated within the heap 
leach pile at the time processing begins, the pile serves to manage 
that material during the operation of the facility. These commenters 
believe this function brings it under the scope of Subpart W. These 
commenters also take a more expansive view, and believe the EPA is 
obligated under the CAA to address the entire process at heap leach 
facilities in the final rule. In this approach, Subpart W would apply 
to ore stockpiles, ore crushing and heaps that are awaiting processing, 
as well as to the heap until placement of the final cover. One 
commenter further recommends that open-air heap leaching not be 
approved, when leaching can be conducted more safely and with lower 
emissions inside a designed enclosure.
    Response: As stated in the response to the previous comment, 
Subpart W will not regulate heap leach piles while they are being 
processed (i.e., during the heap leach pile's operational life). We 
proposed to apply certain management practices to heap leach piles, but 
did not propose to establish a radon emission standard and monitoring 
requirements. Regarding the extension of Subpart W to ores and other 
similar materials, when the EPA initially promulgated Subpart W in 
1986, we identified radon as the radionuclide released to air that 
presented the highest risk at uranium recovery facilities and 
determined that units managing uranium byproduct material or tailings 
were the most significant source of radon emissions (51 FR 34056). 
Since 1986 and re-promulgation in 1989, Subpart W has only regulated 
units that manage uranium byproduct material or tailings

[[Page 5163]]

at uranium recovery facilities. 40 CFR 61.250. Other potential emission 
points in these facilities were not previously the subject of Subpart W 
regulation and were not assessed for the 1989 rulemaking. The EPA's CAA 
section 112(q) review of Subpart W was limited to the existing 
standard. Because Subpart W did not regulate other potential emission 
points, the EPA did not include any other potential emission points in 
its CAA section 112(q) review. In this final rule, the EPA continues to 
regulate the management of uranium byproduct material or tailings from 
conventional mills, from in situ leach facilities and from heap leach 
piles.
    Comment: A significant number of commenters raised objections to 
the proposed requirement that heap leach piles be maintained at 30% 
moisture content as a means to limit radon emissions. Calculations 
submitted by numerous commenters have shown that to maintain a 30% 
moisture content across the heap leach pile would require the pile to 
be almost submerged. The commenters broadly agreed that this is an 
unrealistic goal that could severely undermine the stability of the 
pile. Further, it would result in a significantly greater hydraulic 
head, which raises the risk of liner failure. Several commenters also 
consider the monitoring requirement to be difficult to implement. As 
with the proposal to maintain one meter of liquid in non-conventional 
impoundments, concern was also expressed regarding the source of the 
water. Commenters suggested that a simpler water balance, which would 
involve calculations of the amount of liquid entering and leaving the 
pile, would be a more implementable method of estimating moisture 
content.
    Response: Recognizing the difficulties associated with maintaining 
a 30% moisture content across the heap leach pile, the final rule does 
not include a requirement related to the moisture content of heap leach 
piles. That being said, keeping the pile wet or covered will help 
reduce radon emissions. We encourage operators as well as the NRC and 
NRC Agreement States to consider methods that can be applied during the 
operational life of the heap leach pile.

E. GACT for Non-Conventional Impoundments

1. How did we address non-conventional impoundments in the proposed and 
final rules?
    The purpose of non-conventional impoundments, also known as 
evaporation or holding ponds, is to manage liquids generated during and 
after uranium processing operations. We proposed to require one meter 
of liquid to remain in the impoundment at all times (79 FR 25411). The 
liquid cover was proposed as a management practice that would limit 
radon emissions from the uranium byproduct material or tailings.
    The Subpart W regulation as promulgated in 1989 did not clearly 
distinguish between conventional tailings impoundments and those 
operating as ponds (i.e., those defined as ``non-conventional 
impoundments'' in this final rule). The proposed regulation intended to 
clarify this distinction.
    For non-conventional impoundments, the proposed rule allowed for an 
unlimited number of units to be operating, with no size limitation, but 
required that a depth of one meter of liquid be kept above any 
precipitated solids (uranium byproduct material or tailings). The use 
of the word ``liquid'' is important here. Typically, operators divert 
process water to evaporation or holding ponds, where it may be 
recycled, treated, evaporated, or disposed by injection. Thus, it is 
likely that the liquid entering the impoundment will contain uranium 
byproduct material or tailings in solution or suspension. Some portion 
of this uranium byproduct material or tailings will settle out into 
sediments. In our proposal we did not specify that the one meter of 
liquid covering a non-conventional impoundment be fresh water; however, 
we did refer to ``water'' in the preamble, and the comments demonstrate 
that there has been some confusion about this point.
    Various commenters described the cost of locating fresh water in 
the semi-arid and arid western portions of the United States in order 
to meet the one meter requirement. Other comments focused on the 
limitations in operational flexibility that a fresh water cover would 
create by changing the chemistry of a stream that is often recycled 
back into the extraction process, or noted that this requirement would 
require re-design of impoundments.
    We recognize that this requirement could result in the need to use 
large volumes of water that may not be readily available in the arid to 
semi-arid areas in which most uranium recovery facilities operate. Even 
for facilities that maintain large volumes of process water in ponds, 
there would likely be some demand for fresh water as a supplement to 
maintain the required liquid level. Further, maintaining this level of 
liquid cover would result in placing significantly more hydraulic head 
on the liner systems for the impoundments, which is counter to existing 
state and federal regulations and guidelines for operating these 
systems, as well as a concern to the Agency that the liner would be 
more susceptible to failure.
    In light of these comments, we took a closer look at the proposed 
requirement. The best indicator of potential Rn-222 emissions during 
the impoundment's operating period is the concentration of Ra-226 in 
the liquid and sediment. The BID to support the 1989 rulemaking 
indicates that the Ra-226 concentrations in conventional uranium 
byproduct material or tailings is as much as an order of magnitude 
higher than evaporation pond sediments at the same uranium recovery 
facility (1989 BID Volume 2, Risk Assessments, EPA/520/1-89-006-1, 
Table 9-2, Docket No. EPA-HQ-OAR-2008-0218). We have recognized that 
keeping uranium byproduct material or tailings in conventional 
impoundments wet helps to limit radon emissions. Moreover, this 
management practice is used throughout the industry, even in arid 
regions, and can thus be considered ``generally available.'' We have 
further recognized that the difference between uranium byproduct 
material or tailings that are saturated and those covered with one 
meter of liquid is negligible (79 FR 25398). Therefore, the final 
rule's requirement that solids remain saturated achieves the same goal 
as the proposed standard of maintaining a one-meter liquid cover.
    Commenters also expressed concern over Rn-222 emissions resulting 
from Ra-226 dissolved in the liquid present in non-conventional 
impoundments, as opposed to solid materials in the bottom of the 
impoundment. A number of commenters questioned our conclusion that 
radon emissions from uranium byproduct material or tailings in non-
conventional impoundments could be greatly reduced by keeping the 
solids saturated, and reduced to nearly zero by maintaining a liquid 
cover. The BID shows in Figure 12 that 100% saturated soil reduces 
radon emanation by nearly 95% compared to dry material, while one meter 
of liquid provides a further reduction of about 93%, or an overall 
reduction of greater than 99% (BID Equation 5.1).\18\ In either case, 
radon emissions from non-conventional impoundments would be controlled 
to levels that represent limited risk to public health. However, 
commenters argued that actual data on the liquid contents of non-
conventional impoundments (primarily from the

[[Page 5164]]

White Mesa mill), when evaluated using a correlation in the updated 
risk assessment, showed radon emissions well in excess of 20 pCi/m\2\-
sec.
---------------------------------------------------------------------------

    \18\ See also ``Risk Assessment Revision for 40 CFR part 61 
Subpart W: Task 5--Radon Emissions from Evaporation Ponds,'' S. 
Cohen & Associates, November 2010, Docket No. EPA-HQ-OAR-2008-0218-
0123.
---------------------------------------------------------------------------

    We carefully evaluated the data and emissions analyses submitted by 
commenters. We determined that the data cited by the commenters did not 
support their conclusions. We conclude that our analysis in the 
proposal was correct regarding the characteristics of non-conventional 
impoundments and the radon attenuation that could be achieved. See 
Section IV.E.2 for more detail on this issue.
    To summarize, we received comments that raise concerns regarding 
the economic and technical feasibility, as well as the practical 
effect, of specifying a liquid level for non-conventional impoundments. 
We further confirmed that keeping the sediments in a non-conventional 
impoundment at 100% saturation is nearly as effective as maintaining 
one meter of water (liquid) cover (Figure 12 in the BID for the final 
rule). The cost and logistics of maintaining a one-meter liquid cover 
in arid regions also favor maintaining saturation, especially given 
that saturation effectively controls emissions and will limit economic 
impacts.
    We evaluated management practices in use at non-conventional 
impoundments in the industry that could achieve the goal of limiting 
radon-222 emissions from these units. These units are designed to hold 
liquid, and typically any uranium byproduct material or tailings 
contained in these impoundments is covered by liquid. Maintaining a 
liquid cover over the uranium byproduct material or tailings would 
effectively control radon and is a practice that is generally available 
to owners and operators of non-conventional impoundments. Therefore, we 
have revised the proposed rule language to indicate that the solids in 
a non-conventional impoundment must remain saturated at all times. In 
this final rule, we are establishing this condition, along with the 
liner requirements in 40 CFR 192.32(a)(1), as GACT-based standards for 
non-conventional impoundments. As noted above, this will reduce radon 
emissions by approximately 95% compared to dry conditions. We recognize 
that operators may still have to add water at times to ensure that the 
uranium byproduct material or tailings remain saturated, particularly 
during standby or high-evaporation periods. However, we anticipate that 
the need for additional water will be much less than would be necessary 
to maintain one meter of liquid. Because these impoundments are 
separately required to comply with the requirements at 40 CFR 
192.32(a)(1), we concluded that such a management practice is generally 
available and contributes to the control of radon emissions as 
described more fully in Section IV.A.2.
    The final rule requires that visual evidence of saturation must be 
recorded and maintained by the owner/operator of the non-conventional 
impoundment, which we anticipate can be obtained using a smartphone or 
a digital camera during the routine daily inspections required by NRC 
regulations. Written observations must be recorded daily, with digital 
photographs to be taken at least weekly. Photographs including embedded 
metadata must be uploaded to the Subpart W Impoundment Photographic 
Reporting (SWIPR) Web site maintained by the EPA on at least a monthly 
basis, beginning on the effective date of this final rule.\19\ Until 
that time, and subsequently should the SWIPR site be unavailable, 
digital photographs must be maintained by the facility owner/operator 
and provided to the EPA or authorized State upon request. Should the 
operator determine that the liquid has fallen to a level that exposes 
solid materials, the operator must correct the situation within one 
week, or other such time as specified by the EPA or the authorized 
State. This provides flexibility if the operator needs to take the 
impoundment out of service for a longer period to address the 
situation, such as to repair the liner. Photographs must be taken that 
show conditions before and after the liquid level is adjusted to verify 
that appropriate corrective actions have been taken. There is no limit 
on the size or number of non-conventional impoundments.
---------------------------------------------------------------------------

    \19\ SWIPR is accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov). Information submitted to SWIPR is 
available to the public after review.
---------------------------------------------------------------------------

2. What key comments did we receive on non-conventional impoundments?
    We received a variety of comments related to non-conventional 
impoundments. Many were related to the proposed requirement to maintain 
one meter of liquid in the impoundment. Others related to the potential 
for radon emissions from liquids in the impoundments, and whether those 
risks were properly characterized.
    Comment: Many commenters opposed the proposed requirement to 
maintain one meter of liquid in the impoundment. Commenters primarily 
cited cost and the logistical difficulty of obtaining and transporting 
water as making this proposed requirement overly burdensome, 
particularly in the arid West. A few commenters noted that impoundments 
that had already been approved and operating were not constructed with 
a depth that could accommodate an additional meter of water, 
potentially necessitating costly renovation. Other commenters noted 
that this requirement would have effects on the facility operation, 
where it is necessary to manage evaporative or holding capacity, and to 
control the characteristics of liquids that may be recycled through the 
process. The additional stress on the impoundment liner was also 
raised.
    Some commenters questioned the need for this requirement, and noted 
statements in previous rulemakings that the difference between 
saturation and one meter of water is negligible. Commenters further 
argued that non-conventional impoundments present a small risk in any 
case. A few commenters suggested that a better approach would be to 
require that solid materials in the impoundment remain saturated, with 
no solids visible above the liquid level.
    Response: We recognize the concerns raised regarding maintaining 
one meter of liquid in non-conventional impoundments. Because we 
determined that radon emissions can be controlled if the solids in non-
conventional impoundment remain saturated, the final rule does not 
include a requirement to maintain one meter of liquid in the 
impoundments. Instead, the final rule adopts the approach suggested by 
the commenters. Solid materials in the impoundment must remain 
saturated, with no solids visible above the liquid level. This will 
achieve a reduction of roughly 95% compared to emissions from dry 
material. Saturation must be documented by written and visual records, 
with digital photographs taken on at least a weekly basis. We disagree 
that the non-conventional impoundments present such a small risk that 
they need not be regulated under Subpart W.
    Comment: Commenters find difficulties in measuring compliance with 
the proposed one meter liquid requirement. One commenter believes 
direct measurements will be difficult because of the density of 
sediments and may present health and safety risks to workers. The 
commenter suggests that calculations based on mass and liquid balances 
would be more effective. Another commenter makes a similar suggestion, 
that the one meter requirement be replaced with a calculation to take 
into account site-specific factors and give operators

[[Page 5165]]

greater flexibility. A third commenter sees problems with the slope of 
the impoundment and the distance that must be observed, and notes that 
past experience suggests that measuring devices (such as pressure 
transducers) will need frequent maintenance and calibration. The 
commenter prefers to have a simple permanent indicator allowing visual 
confirmation, rather than measurement.
    Response: We appreciate these comments and thoughtful suggestions. 
The final rule does not include a requirement to maintain one meter of 
liquid in the impoundments. Instead, the final rule requires that solid 
materials in the impoundment must remain saturated, with no solids 
visible above the liquid level. Although we proposed a one meter liquid 
cover, comments and further evaluation persuaded us that keeping solids 
saturated controls emissions nearly as effectively as maintaining a 
one-meter liquid cover. As explained in Section IV.E.1, we have 
recognized that keeping uranium byproduct material or tailings wet 
helps to limit radon emissions. We have further recognized that the 
difference between uranium byproduct material or tailings that are 
saturated and those covered with one meter of liquid is negligible. See 
Section IV.E.1 and 79 FR 25398.
    Comment: Some commenters argue that the potential for radon 
emissions from non-conventional (liquid) impoundments has been greatly 
understated. They state that the general position taken by regulatory 
agencies (including the EPA) and industry that these impoundments 
represent a negligible source of radon compared to the solids in 
conventional impoundments is not supported by data. In particular, the 
commenters believe that radium in solution or suspension in the liquids 
has been overlooked as a potential source of radon, compared to solids 
or sediments in the bottom of the non-conventional impoundments. 
Commenters cited data from the 2013 and 2014 ``Annual Tailings System 
Wastewater Sampling Report'' submitted by Energy Fuels to the State of 
Utah to support this contention. Using radium data from liquid samples 
collected from Cells 1, 3, 4 and 4A at the White Mesa Mill and a 
correlation to radon flux from liquids in the EPA's risk assessment to 
support the rulemaking (the ``Task 5'' report, Docket No. EPA-HQ-OAR-
2008-0218-0123), the commenters calculate radon fluxes well in excess 
of 20 pCi/m\2\-sec (up to 2,317 pCi/m\2\-sec from Cell 1 in 2014). The 
commenters further note a significant increase in the radium 
measurements for three of the four impoundments from 2013 to 2014, 
likely attributable to evaporation and concentration of the radium in 
solution (Cell 3 showed a significant increase from 2012 to 2013, but 
dropped in 2014). They conclude that the risk to public health 
associated with radon emissions from non-conventional impoundments is 
much greater than the EPA has acknowledged.
    Response: The EPA disagrees that the data provided by commenters 
support their conclusion that the liquids have been underestimated as a 
source of radon. First, the laboratory analyses included in the 
sampling report refer to ``Total Alpha Radium'' (or ``Gross Radium 
Alpha'') and specify the analytical method as EPA Method 900.1.\20\ 
This method cannot distinguish between different alpha-emitting 
isotopes of radium, which are all chemically identical. In addition to 
Ra-226, the isotope of concern that decays to form Rn-222, the sample 
may also contain Ra-224 (a decay product of Thorium-232) and Ra-223 (a 
decay product of Uranium-235). Because of the vast difference in their 
decay rates,\21\ Ra-224 and Ra-223 need be present in much smaller 
amounts (by mass) to have the same activity as Ra-226. For example, one 
gram of Ra-226 will have the same activity as about 6.25 micrograms 
(6.25 x 10-\6\ grams) of Ra-224. It is known that the White 
Mesa Mill has processed materials containing Th-232, which makes it 
likely that Ra-224 is present in some amount. Given these sources of 
uncertainty, these results cannot definitively represent Ra-226 
concentrations. Other sources of uncertainty could include interference 
from barium present in the liquid sample, as Method 900.1 relies upon 
precipitation with barium sulfate to separate the radium. Moreover, 
while Method 900.1 can essentially separate uranium from the sample, it 
is less effective at separating other alpha-emitting radionuclides, 
such as isotopes of thorium. Thus, some small amounts of uranium and 
thorium could solubilize and ``carryover'' into the precipitated 
sample, which would also affect the analysis. Given the numerous 
uncertainties associated with the data relied upon by the commenters, 
these data cannot reliably serve as a surrogate for Ra-226. Without 
specific isotopic analyses, which were not performed on the samples 
presented in the 2013 and 2014 reports, the actual Ra-226 
concentrations cannot be determined.
---------------------------------------------------------------------------

    \20\ ``Prescribed Procedures for Measurement of Radioactivity in 
Drinking Water,'' EPA-600/4-80-032, August 1980, Docket No. EPA-HQ-
OAR-2008-0218.
    \21\ Radium-226 has a half-life of 1,600 years, while Radium-224 
and -223 have half-lives of 3.66 days and 11.43 days, respectively. 
EPA Method 900.1 has been used by drinking water systems to show 
compliance with the regulatory standard of 5 pCi/L for combined Ra-
226 and Ra-228, which is well below the activity found in effluents 
from uranium processing. Ra-228 is a pre-cursor of Ra-224 that 
decays by beta emission and has a half-life of 5.75 years. If the 
result is below 5 pCi/L using Method 900.1, there is no need for 
additional analysis. Half-life is the amount of time for one-half of 
the radionuclide to decay. Further, although Ra-223 and Ra-224 decay 
to form Rn-219 and Rn-220 (also known as ``thoron''), respectively, 
these isotopes of radon are also very short-lived (half-lives less 
than one minute each) and therefore are not considered to be of 
concern for exposures to the public.
---------------------------------------------------------------------------

    The 2015 annual wastewater sampling report for White Mesa \22\ 
contains additional information to clarify this situation. Samples 
taken on two separate occasions from each of the cells (compared to the 
single sampling conducted in previous years) were analyzed not only for 
total alpha radium, but also for the isotope Ra-226, using EPA Method 
903.1 (``Prescribed Procedures for Measurement of Radioactivity in 
Drinking Water,'' Docket No. EPA-HQ-OAR-2008-0218). These results 
confirm that total alpha radium is not the correct basis for 
calculations of radon emissions. Table 4 below shows the 2015 results 
for Cell 1, compared to the 2013 and 2014 results that were cited by 
the commenters. Cell 1 has been in use since 1981, and has only been 
used to manage liquids (i.e., no solids from the mill have been placed 
in it). It consistently shows among the highest levels of total alpha 
radium.
---------------------------------------------------------------------------

    \22\ Environmental reports for the White Mesa Mill are available 
from the Utah Department of Environmental Quality at http://www.deq.utah.gov/businesses/E/energyfuels/whitemesamill.htm.

     Table 4--Monitoring Results From Cell 1 at the White Mesa Mill
------------------------------------------------------------------------
                                   Total alpha
                                 radium (pCi/L)       Ra-226 (pCi/L)
------------------------------------------------------------------------
2013...........................          32,700  Not analyzed.

[[Page 5166]]

 
2014...........................         331,000  Not analyzed.
2015 Sample 1..................          73,800  829.
2015 Sample 2..................         735,000  1,110.
------------------------------------------------------------------------
Source: ``2015 Annual Tailings System Wastewater Sampling Report,''
  Energy Fuels.

    The Ra-226 concentrations found in 2015 are consistent with 
historical data, also included in the sampling reports. For the period 
1980-2003, the maximum concentration of Ra-226 recorded is 1,690 pCi/L, 
based on sampling from Cell 1, Cell 2, and Cell 3 (it is not specified 
which cell recorded the maximum concentration). Table 6 of the Task 5 
report estimates that, based upon site-specific conditions at the White 
Mesa Mill, a Ra-226 concentration of 1,000 pCi/L in impoundment liquids 
would result in a radon flux of approximately 7 pCi/m\2\-sec. Using 
this correlation, the average radon flux from Cell 1 in 2015 would be 
slightly less than 7 pCi/m\2\-sec. The highest level of Ra-226 in 2015 
from the other impoundments was 772 pCi/L in Cell 4A, which translates 
to a radon flux of about 5.4 pCi/m\2\-sec. Further, based on the 
maximum Ra-226 concentration recorded from 1980-2003, the calculated 
radon flux would be roughly 11.8 pCi/m\2\-sec. These results indicate 
that the radon flux from Ra-226 suspended or dissolved in liquids in 
the non-conventional impoundments at White Mesa is controlled to a 
level that is within the range that the EPA determined to be acceptable 
during the development of Subpart W, without taking additional 
measures.
    These results are also consistent with information reported for 
liquid impoundments at ISL facilities (see Tables 7, 8 and 9 of the 
Task 5 report). They also suggest that the noteworthy fluctuations in 
recent years may not be directly attributable to the radium content of 
the liquids, but may result from the analytical method used. ``Total'' 
or ``gross'' analytical methods are generally considered screening 
tools whose results are more susceptible to other influences. Energy 
Fuels states that the individual isotopic analyses ``show that the 
increasing gross alpha results are being caused by matrix interference 
due to the nature of the tailings solution and are not representative 
of gross alpha from radium concentrations in the solution'' (Energy 
Fuels, 2015 annual wastewater sampling report, page 15). Similar 
fluctuations occurred for all the impoundments (although, as noted 
earlier, Cell 3 showed a significant increase in 2013, with a decrease 
in 2014).
    As an additional source of information, the facility's 2015 ``Semi-
Annual Effluent Monitoring Report'' (July through December) provides 
radon monitoring data from air monitoring stations posted around the 
impoundments. The facility resumed monitoring for radon in 2013 and the 
data presented in Attachment J of the report show that emissions have 
been within the limits calculated to correspond to a 25 mrem annual 
dose for continuous exposure at each monitoring station. These limits 
serve as As Low As Reasonably Achievable (ALARA) goals for the 
facility.
    In most cases, results are well below that level. The highest 
annual result (four consecutive quarters) can be seen for Station BHV-
4, which is located directly south of the impoundments but still within 
the White Mesa facility boundary. A person located at this point during 
2015 would have incurred a dose of approximately 16 mrem \23\ (average 
quarterly results of roughly 0.31 pCi/L, compared to a calculated limit 
of 0.5 pCi/L). The single highest quarterly reading is listed at 
Station BHV-6, which is to the southeast of the impoundments at the 
facility boundary. The reading for the fourth quarter of 2013 is 
approximately 88% of the calculated limit (0.73 compared to 0.83, 
translating to a quarterly dose of about 5.5 mrem at that location). 
However, readings for the previous two quarters were recorded as zero 
and readings for the next quarters were significantly lower as well. 
There is fluctuation in these results as well, which depends to some 
extent on wind direction, but overall the results indicate that radon 
from the impoundments is not a significant public health concern.
---------------------------------------------------------------------------

    \23\ Corresponding to an annual risk of fatal cancer of less 
than 1 x 10-\5\. See Section 4 of the BID.
---------------------------------------------------------------------------

    Both the sampling data from the non-conventional impoundment cells 
and the radon data from the air monitoring stations at the White Mesa 
Mill support the EPA's conclusion that emissions from the liquids in 
non-conventional impoundments represent a limited source of radon and 
does not support commenters' argument to the contrary.
    Comment: Some commenters request clarification that Subpart W 
should not apply to impoundments that only contain water that has been 
treated to meet effluent limits. The commenters see this as having no 
regulatory benefit, but a potential additional cost to operators who 
must meet the more stringent requirements in 40 CFR 192.32(a)(1). 
Commenters also suggest we define a threshold level of radium or 
uranium content below which liquids no longer must be managed as 
uranium byproduct material or tailings.
    Response: The purpose of Subpart W is to control radon emissions 
from sources containing uranium byproduct material or tailings at 
uranium recovery facilities. The EPA agrees that if an impoundment does 
not contain uranium byproduct material or tailings, it is not subject 
to the requirements of Subpart W. The EPA is not defining a 
concentration or level of radium or uranium at which treated liquids 
would no longer be considered uranium byproduct material or tailings. 
Instead, such impoundments can be identified and their status can be 
addressed during the construction application review under 40 CFR part 
61, subpart A.
    Subpart W also does not apply to impoundments constructed for the 
purpose of managing liquids generated by closure or remediation 
activities, when they are used solely for that purpose. Impoundments 
that do not contain uranium byproduct material or tailings resulting 
directly from uranium recovery operations are not considered to be non-
conventional impoundments as defined in Subpart W.
    However, non-conventional impoundments remain subject to the 
requirements of Subpart W until they enter final closure pursuant to an 
approved reclamation plan for that impoundment, even if at some point 
in their operational life they are used for the purpose of managing 
liquids from closure or remediation activities. EPA recognizes that 
non-conventional impoundments that are subject to

[[Page 5167]]

Subpart W may subsequently transition to a use that supports facility 
closure or site remediation (e.g., when an ISL wellfield enters into 
the groundwater restoration phase, and is no longer recovering 
uranium). Some parties may argue that a non-conventional impoundment's 
receipt of waste associated with facility closure or site remediation 
appears analogous to the ability of licensees to obtain a license 
amendment and have a reclamation plan which provides for placement of 
remediation wastes in conventional impoundments during the closure 
process. Using this analogy, some may contend that non-conventional 
impoundments should not be subject to Subpart W when receiving such 
wastes. However, such a non-conventional impoundment could later be 
used to manage liquids from uranium recovery operations at the next 
wellfield. To ensure that non-conventional impoundments that receive 
uranium byproduct material and tailings are managed in accordance with 
Subpart W, and to promote clarity and consistency with the promulgated 
regulations, Subpart W applies to non-conventional impoundments during 
the entire operating life of an impoundment which receives, or has 
received, uranium byproduct material or tailings directly from active 
uranium recovery operations. Changing a non-conventional impoundment's 
Subpart W applicability based on the primary use of the impoundment at 
any particular time during its operational life would cause unnecessary 
confusion and would be inconsistent with the regulations.
    Operationally, this should not represent a burden to licensees. If 
the impoundment is being used to manage liquids from closure or 
remediation activities, it should remain in compliance with the 
requirement to retain sufficient liquid to cover solid materials in the 
impoundment. Further, because there is no restriction on the number of 
such impoundments that may be operating at one time, the licensee will 
not face the same pressure to begin closure as applies to conventional 
impoundments using the phased disposal approach.
    Comment: A commenter finds the discussion of non-conventional 
impoundments confusing. The commenter believes we have inconsistently 
and inaccurately described the purpose of these impoundments, the 
nature of the materials in them, and our regulatory approach. The 
commenter wishes us to clarify that the liquids are not held in the 
impoundments for the purpose of covering uranium byproduct material or 
tailings, but the liquid in fact contains (or is) uranium byproduct 
material or tailings. The commenter questions how the liquid can be 
used to control radon emissions, when the liquid is itself in need of 
control, and requests that we consider that liquids high in radium 
content may actually cause an increase in emissions.
    Response: The purpose of non-conventional impoundments (evaporation 
or holding ponds) is to receive liquids generated by the uranium 
processing operation. Uranium byproduct material or tailings may be 
suspended or dissolved in these liquids. Some portion of the material 
will precipitate out and settle on the bottom of the impoundment. In 
some sense, the liquid itself is uranium byproduct material or tailings 
because it is a waste from the concentration or extraction process. The 
definition of ``non-conventional'' impoundment accurately conveys the 
concept that these impoundments ``contain uranium byproduct material or 
tailings suspended in and/or covered by liquids.'' As noted in the 
previous comment response, impoundments containing only treated water 
and impoundments constructed for the purpose of managing liquids from 
closure or remediation activities are not non-conventional impoundments 
as defined by Subpart W, because they do not contain uranium byproduct 
material or tailings resulting directly from active uranium recovery 
operations.
    While radium contained in the liquid will contribute to radon 
emissions, those emissions will be attenuated to some degree by the 
liquid in which it is contained. Further, liquid on top of solid 
materials will effectively limit radon emissions from those solids 
reaching the air, even if the liquid itself contains radium. While 
higher concentrations of radium in the liquid will generate more radon, 
concentrations in non-conventional impoundments have not been seen to 
reach levels of concern. See the response to the earlier comment in 
this section.
    Comment: Many commenters expressed opinions related to limiting the 
size of impoundments. Some commenters believe Subpart W should contain 
limits on the size of non-conventional impoundments. The commenters 
believe that larger impoundments are more likely to fail and limits 
must be imposed to minimize the potential for ground water 
contamination. One commenter also believes the number of impoundments 
should be limited. Another commenter does not believe we have 
adequately supported our conclusion that the requirements of 40 CFR 
192.32(a)(1) will provide protection against extreme weather events and 
may be subject to greater turbulence. Regarding our reference to an 
impoundment of 80 acres, one commenter wishes us to clarify that no 
actual impoundment has been as large as 80 acres, but this size has 
been used only for modeling purposes. Another disputes our statement 
that it is reasonable to assume that such impoundments will not exceed 
80 acres in area, simply because one never has.
    Response: We have chosen not to limit the size of non-conventional 
impoundments because they are not as significant a source of radon 
emissions and can be readily controlled by maintaining saturation of 
solid materials, but also because they provide operational flexibility 
to uranium recovery facilities that may need to manage, on a temporary 
basis, large volumes of water that can then be recycled into the 
process. Regarding the maximum size of such impoundments, we referred 
to 80 acres as a ``reasonable maximum approximation'' for estimating 
cost, clearly noting that it is ``the largest size we have seen'' (79 
FR 25401).
    Comment: A commenter states that the current and proposed rules do 
not actually contain any measures to control releases of impoundment 
contents to the surface or subsurface during extreme weather events. 
The commenter asserts that the EPA has not provided any data to support 
the conclusion that the requirements of 40 CFR 264.221 will prevent 
dispersion of contents in severe events. The commenter expresses 
concern that generally available technologies do not exist that could 
prevent dispersion of contents or failure of the impoundment in a 
severe event such as a tornado or hurricane.
    Response: As discussed in the proposal, we believe the design and 
engineering requirements for impoundments in 40 CFR 264.221, referenced 
in 40 CFR 192.32(a)(1), provide a sound basis for protection against 
reasonably foreseeable weather events. The provisions related to 
avoiding overtopping (essentially, spillage or dispersion) from 
``normal or abnormal operations,'' ``wind and wave action,'' or 
``rainfall,'' as well as the requirement to maintain integrity and 
prevent massive failure of the dikes, lay a foundation for addressing 
the commenter's concerns. To satisfy these conditions, design of 
impoundments at any specific site would likely take into account 
regional climate and the

[[Page 5168]]

magnitude of events such as 100- or 500-year precipitation, or the 
likelihood of tornados or hurricanes.

F. Definitions, References and Conforming Editorial Revisions

1. How did we address definitions, reference and conforming editorial 
revisions in the proposed and final rules?
a. Definition of ``Operation'' and ``Final Closure''
    We proposed a relatively minor change to the definition of 
``operation'' (79 FR 25404). Under Subpart W as promulgated in 1989, an 
impoundment was in operation when new tailings were being emplaced, 
from the day that tailings are first placed in the impoundment until 
the day that final closure begins. There has been some confusion over 
this definition. We proposed to amend the definition of ``operation'' 
in the Subpart W definitions at 40 CFR 61.251 to replace the reference 
to ``new'' tailings with the broader term ``uranium byproduct material 
or tailings'' at 79 FR 25405.
    We received comments from across the spectrum of stakeholders who 
disliked this definition. Commenters from industry said we did not take 
into account the period between cessation of placement of uranium 
byproduct material or tailings into an impoundment and physical closure 
with an approved closure plan. This period can sometimes last for years 
while the uranium byproduct material or tailings are dewatered to an 
extent that heavy machinery can be used to emplace the final closure 
radon barrier. Also, the impoundment(s) are often used for dismantling 
the facility, for disposal of other liners, etc. Extending the 
operational period and Subpart W jurisdiction during the entire closure 
period could result in a milling facility having two operating 
impoundments in the closure process and no ability to operate a third 
impoundment to receive uranium byproduct material or tailings from 
operations. Other commenters claimed that operators were taking 
advantage of the existing definition by claiming that an impoundment is 
``in closure'' but taking no concrete action to implement a closure 
plan or apply a final cover.
    We do not intend to extend the jurisdiction of Subpart W to include 
the period during which closure activities are being conducted. The 
proposal was intended to clarify that an impoundment remains 
``operating'' until it enters closure, even if it is not receiving 
newly-generated uranium byproduct material or tailings from facility 
processing (79 FR 25405). Further, we note that the definition in 
Subpart W is consistent with those in 40 CFR 192.31 and 10 CFR part 40, 
Appendix A, which were in fact derived from Subpart W. Thus, we find 
this concern to be misplaced. The final rule adopts the definition of 
``operation'' as it was proposed.
    We did not propose to include a definition of ``closure''; however, 
we realize that a lack of clarity on the concept of closure, what it 
involves and when it begins has affected the understanding of Subpart 
W. In particular, the use of the term ``final closure'' in the 
definition of ``operation'' does not, by itself, provide sufficient 
clarity on the end of operation. As described earlier, we received a 
number of comments making suggestions or raising concerns on this 
point. As noted above, the definition of ``operation'' in Subpart W 
served as the basis for the definitions later adopted in 40 CFR part 
192 and 10 CFR part 40, Appendix A. Further, both 40 CFR part 192 and 
10 CFR part 40, Appendix A adopted definitions and requirements related 
to closure that address some aspects of the comments we received 
related to Subpart W. The more appropriate action is to retain the 
definition of ``operation'' and clarify the meaning of final closure in 
a separate definition. Therefore, the final rule incorporates a new 
definition of ``final closure'' at 40 CFR 61.251(n).
    We emphasize two aspects of this new definition that we believe 
will help address concerns regarding the timeliness and predictability 
of closure activities. First, impoundments or heap leach piles will 
remain subject to Subpart W until the owner or operator provides 
written notice that the impoundment is entering final closure. Second 
is the reference to the reclamation plan for the impoundment or heap 
leach pile. We have heard some comments, specifically related to the 
Cotter mill, that the facility should still be subject to Subpart W 
because it has never had an approved reclamation or closure plan; 
however, the facility no longer has an operating license under which it 
would conduct activities subject to the requirements of Subpart W.
    The reference to a reclamation plan in the definition of ``final 
closure'' does not affect that Subpart W only applies to operational 
units and does not cover units that are in closure. Rather, it makes 
clear our expectation, also found in 40 CFR part 192 and 10 CFR part 
40, Appendix A, that the NRC or the Agreement State require and approve 
such a plan. It also establishes that notice to the NRC or the 
Agreement State and an approved reclamation plan are necessary 
prerequisites for determining that the impoundment in question is no 
longer subject to the requirements of Subpart W. The final rule is 
adopting the terminology employed in NRC regulations. In 10 CFR part 
40, Appendix A, NRC identifies a reclamation plan as applicable to 
individual impoundments, while the closure plan is a more comprehensive 
document that addresses all aspects of facility closure and 
decommissioning, including any necessary site remediation. A 
reclamation plan prepared and approved in accordance with NRC 
requirements in 10 CFR part 40, Appendix A, is considered a reclamation 
plan for purposes of Subpart W. The reclamation plan may be 
incorporated into the larger facility closure plan.
    A number of commenters expressed concern that the issue of delayed 
closure would have been addressed by 40 CFR part 61, subpart T (40 CFR 
61.220-226), which required that impoundments that are no longer 
accepting tailings be brought into compliance (i.e., covered) within 
two years, or in accordance with an approved compliance agreement if it 
is not feasible to complete closure within two years. In accordance 
with a 1991 Memorandum of Understanding (MOU), the EPA and the NRC 
amended 40 CFR part 192 and 10 CFR part 40, Appendix A, respectively, 
to incorporate provisions related to the timing and requirements of 
activities conducted during the closure period. The EPA subsequently 
rescinded subpart T in 1994, finding that the NRC regulatory program 
protected public health with an ample margin of safety to the same 
level as would implementation of subpart T (59 FR 36280, July 15, 
1994). The commenters correctly noted that in that action the EPA 
retained the authority to reinstate subpart T should we determine that 
the NRC was not implementing it as we intended. The Agency has no plans 
to reinstate subpart T at this time, but takes this opportunity to 
emphasize that closure of impoundments should be conducted 
expeditiously, taking only the time that is truly necessary to dewater 
or otherwise prepare the uranium byproduct material or tailings before 
application of interim and final covers.
b. Liner Requirements in 40 CFR 192.32(a)(1)
    We proposed specific provisions for conventional impoundments, non-
conventional impoundments and heap leach piles to explicitly convey 
that any impoundment at a uranium recovery

[[Page 5169]]

facility that contains uranium byproduct materials or tailings would be 
subject to the Subpart W liner requirements. The 1986 and 1989 versions 
of Subpart W included a reference to 40 CFR 192.32(a); 40 CFR 192.32(a) 
incorporates the surface impoundment design and construction 
requirements of hazardous waste surface impoundments regulated under 
the Resource Conservation and Recovery Act (RCRA), found at 40 CFR 
264.221. Those requirements state that the impoundment shall be 
designed, constructed and installed to prevent any migration of wastes 
out of the impoundment to the adjacent subsurface soil or ground water 
or surface water at any time during the active life of the impoundment. 
Briefly, 40 CFR 264.221(c) requires that, for new impoundments 
constructed after January 29, 1992,\24\ the liner system must include:
---------------------------------------------------------------------------

    \24\ 57 FR 3487, January 29, 1992. These specifications also 
apply to lateral expansions of existing surface impoundment units or 
replacements of existing surface impoundment units beginning 
construction or reuse after July 29, 1992. At the time of the 1986 
and 1989 Subpart W rulemakings, double liners and leachate 
collection systems were specified for new impoundments, but the 
requirements did not contain this level of detail. The requirement 
for double liners was promulgated on July 15, 1985 (50 FR 28747).

    1. A top liner designed and constructed of materials (e.g., a 
geomembrane) to prevent the migration of hazardous constituents into 
the liner during the active life of the unit.
    2. A composite bottom liner consisting of at least two 
components. The upper component must be designed and constructed of 
materials (e.g., a geomembrane) to prevent the migration of 
hazardous constituents into this component during the active life of 
the unit. The lower component must be designed and constructed of 
materials to minimize the migration of hazardous constituents if a 
breach in the upper component were to occur. The lower component 
must be constructed of at least three feet of compacted soil 
material with a hydraulic conductivity of no more than 1 x 
10-\7\ cm/sec.
    3. A leachate collection and removal system between the liners, 
which acts as a leak detection system. This system must be capable 
of detecting, collecting and removing hazardous constituents at the 
earliest practicable time through all areas of the top liner likely 
to be exposed to the waste or liquids in the impoundment.

    There are other requirements for the design and operation of the 
impoundment, and these include construction specifications, slope 
requirements, sump requirements and liquid removal requirements. As 
part of the proposed rule, we examined these provisions to help 
determine whether Subpart W adequately addresses extreme weather 
events. We determined that the requirements in 40 CFR 264.221 
satisfactorily address such events.
    The proposal did not adopt a new approach. Instead, it carried 
forward the approach adopted in the 1989 rulemaking. That rulemaking 
included Sec.  61.252(c), which broadly required all impoundments, 
including those in existence prior to the promulgation of 40 CFR part 
192, to comply with the requirements of 40 CFR 192.32(a). The 1986 
rulemaking had not applied the requirements of 40 CFR 192.32(a) to 
impoundments in existence when the 1986 rule was promulgated, as these 
impoundments were anticipated to cease accepting uranium byproduct 
material or tailings by the end of 1992 (51 FR 34066). The 1989 
rulemaking lifted this restriction as well as the exemption from the 
requirements of 40 CFR 192.32(a) (54 FR 51680).
    We did not propose to remove the liner requirements or request 
comment on whether they should be retained. We proposed to refer only 
to 40 CFR 192.32(a)(1) because Sec.  192.32(a) includes provisions that 
extend well beyond the design and construction of impoundments, such as 
ground water monitoring systems and closure requirements. These aspects 
do not fall under the purview of Subpart W, and they are removed in 
this action.
    This final rule incorporates the revised reference to 40 CFR 
192.32(a)(1) for all impoundments that contain uranium byproduct 
material or tailings and establishes this requirement as an element of 
GACT-based standards for conventional impoundments, non-conventional 
impoundments, and heap leach piles. The provision in the 1989 rule that 
extended this requirement to conventional impoundments in existence as 
of December 15, 1989 is moved to Sec.  61.252(a)(1), which addresses 
those impoundments.
    We received a comment suggesting that we explicitly cite 40 CFR 
264.221(c) as the criteria that all impoundments are required to meet. 
This provision was not incorporated into regulation until 1985 (50 FR 
28747). Adopting the commenter's approach would require impoundments 
constructed before 1985 to upgrade or close, which we did not propose 
to require. Those older impoundments are required to comply with the 
provisions of 40 CFR 264.221 that are applicable to them. The 
commenter's approach would also eliminate consideration of Sec.  
264.221(d), which allows for an alternative design or operating 
practices if ``such design and operating practices, together with 
location characteristics'' would prevent migration of hazardous 
constituents and allow detection of leaks at least as effectively as 
the requirements of Sec.  264.221(c). It is not appropriate to 
eliminate this flexibility, particularly for sites that may employ 
improved liner materials or have exceptional natural characteristics 
that lend themselves to such a demonstration.
c. Eliminating ``As Determined by the Nuclear Regulatory Commission''
    As described in the preceding section, Subpart W as promulgated in 
1989 required impoundments to be constructed in accordance with the 
requirements cited in 40 CFR 192.32(a). This provision also included 
the phrase ``as determined by the Nuclear Regulatory Commission.''
    As described in the preceding section, 40 CFR 192.32(a) also 
contains provisions related to ground water protection and closure 
activities, which are not within the scope of Subpart W. It is 
appropriate that the NRC be the sole regulatory agency for implementing 
and enforcing these provisions. We proposed to eliminate the phrase 
``as determined by the Nuclear Regulatory Commission'' from Subpart W 
to clarify that EPA is an approval authority for Subpart W, but 
specifically for the impoundment engineering and construction 
requirements in 40 CFR 192.32(a)(1).
    We received a number of comments from industry objecting to this 
change on the grounds that it would create dual regulation with NRC, 
thus leading to inefficiencies and the potential for one agency to 
approve an application while the other denied it. We disagree with 
these commenters, as described in detail in the next section. The final 
rule eliminates the phrase ``as determined by the Nuclear Regulatory 
Commission'' from 40 CFR 61.252(a)(2)(i) and (ii).
2. What key comments did we receive on definitions, references and 
conforming editorial revisions?
    We received a number of comments related to the issue of operation 
and closure, either to extend the jurisdiction of Subpart W or to limit 
it. Commenters also expressed views on the liner requirements and their 
relation to groundwater protection or older impoundments. In connection 
with the liner requirements, a number of commenters disagreed with the 
proposal to eliminate the phrase ``as determined by the Nuclear 
Regulatory Commission,'' suggesting that it will create dual regulation 
and exceeds our rulemaking authority. Although we did not propose to 
revise it, we also received some comment related to the definition of 
``uranium byproduct material or tailings.''

[[Page 5170]]

    Comment: A number of commenters advocated that the scope of Subpart 
W be extended to include all activities undertaken to achieve final 
closure of the impoundment (see also the next comment in this section). 
As defined in Subpart W, ``operation'' ends ``the day that final 
closure begins'' (40 CFR 61.251(e)). Many of the commenters would like 
this definition extended and explicitly stated that Subpart W should 
apply until the final cover is installed on the impoundment (or, for 
non-conventional impoundments, until the impoundment is removed, if 
that is the closure approach).
    Response: Subpart W has never addressed remediation or reclamation 
activities undertaken to close the impoundment or the site and EPA did 
not propose to expand the scope of the rule to cover such activities. 
Comments on whether the separate regulations that apply during closure 
and until the final cover is installed are sufficient or whether 
additional regulations are needed to cover activities during that time 
period are beyond the scope of this section 112(q) review of Subpart W 
and thus EPA has no obligation to respond. However, a goal of this 
rulemaking was to provide clarity regarding when the management of 
uranium byproduct material or tailings is no longer subject to Subpart 
W. The final rule specifies that Subpart W no longer applies at the 
beginning of closure and further defines when closure begins. For 
informational purposes only, EPA discusses below some of the 
regulations that apply during the closure period. EPA did not reopen or 
accept comment on any aspects of these regulations.
    In 1989, in conjunction with the promulgation of Subpart W, the EPA 
promulgated 40 CFR part 61, subpart T (40 CFR 261.220-226) to address 
the closure period and final disposal for conventional tailings 
impoundments (54 FR 51682). Subpart T required closure of impoundments 
to be complete within two years after ceasing operations.
    In 1991, by Memorandum of Understanding (MOU) with the NRC, the two 
agencies agreed to take action to clarify the timing for closure of 
impoundments and processing sites. As part of this agreement, the EPA 
amended 40 CFR part 192 (58 FR 60341, November 15, 1993) and rescinded 
subpart T (59 FR 36302, July 15, 1994). The NRC subsequently amended 10 
CFR part 40, Appendix A, consistent with the EPA's amended 40 CFR part 
192 (59 FR 28220, June 1, 1994). The MOU included the goal that all 
sites could be closed and in compliance with radon emission standards 
by 1997 or within seven years of the date on which existing operations 
cease and standby sites enter disposal status. The MOU did not address 
Subpart W because Subpart W does not apply during closure.
    The MOU and subsequent regulatory actions created a more 
comprehensive and coordinated framework for managing uranium processing 
wastes. Further, a settlement agreement with stakeholders provided 
additional detail to the MOU that, in part, allowed the EPA to make a 
finding under the CAA that the NRC's regulatory program protected 
public health with an ample margin of safety. This supported the 
Agency's decision to rescind subpart T.
    In their respective rulemakings, the agencies essentially adopted 
the Subpart W definition of ``operation'' and included provisions 
related to closure that would allow certain activities related to waste 
management during the closure process. Among these were provisions that 
would allow wastes to be placed in impoundments that were also either 
in closure or had completed closure (final cover). These authorizations 
would not change the status of the impoundment or site, as we explained 
in our rulemaking to amend 40 CFR part 192: ``Even if a portion of a 
site is authorized to remain accessible for disposal of byproduct 
materials during the closure process or after placement of a permanent 
radon barrier consistent with the Settlement Agreement, as described 
above, this will not cause a nonoperational uranium mill tailings 
disposal site to revert to an operational site as defined by 40 CFR 
192.31(q)'' (58 FR 60348, November 15, 1993).
    Similarly, the NRC addressed this point in its 1993 proposed rule 
to amend 10 CFR part 40, Appendix A in response to a comment from an 
NRC Agreement State:

    [Agreement State] Comment. The word ``portion'' should be 
deleted from paragraph (3) of Criterion 6A.
    [NRC] Response. This provision allows limited disposal during 
closure as an exception to the definition of operation. If the whole 
impoundment is involved in waste disposal and no reclamation 
activities are proceeding, the impoundment would be considered 
operational and continue to be under appropriate requirements for 
operation. Note, one site may have both an operational impoundment 
and a non-operational impoundment with the applicable regulations 
applying to each (58 FR 58659, November 3, 1993, emphasis in 
original).

    The final rule includes the definition of ``operation'' as it was 
proposed, which makes it fully consistent with the definitions in 40 
CFR part 192 and 10 CFR part 40, Appendix A. We are also adopting a 
definition of ``final closure'' that clarifies that Subpart W does not 
apply to impoundments that are being managed under an approved 
reclamation plan for that impoundment or the facility closure plan.
    Comment: Several commenters stated that the current regulatory 
scheme allows an unacceptable period during closure activities when 
impoundments are not being monitored or otherwise managed to limit 
radon emissions. They further argue that closure is not being conducted 
in a manner that will lead to timely installation of a final cover or 
removal of an evaporation or holding pond. They cite periods of decades 
during which tailings are being ``dewatered'' or impoundments are used 
to deposit wastes from decommissioning activities, while the drying-out 
of impoundments allows increased radon emissions. Commenters attribute 
this in some part to the Agency's rescission of subpart T, which called 
for installation of final covers on conventional tailings impoundments 
within two years of the cessation of operations. One commenter notes 
that an impoundment undergoing closure will be required to demonstrate 
compliance with the 20 pCi/m\2\-sec radon emissions standard only if it 
requests extension of the milestones in the closure plan, where it may 
not have been required to monitor previously under Subpart W.
    Response: The EPA did not propose to extend the jurisdiction of 
Subpart W beyond the operational phase, nor did we request comment on 
regulations that are applicable to closure activities. We are under no 
obligation to respond to such comments. However, one purpose of this 
rulemaking was to clarify at what point Subpart W no longer applies to 
the management of uranium byproduct material or tailings. The final 
rule specifies that Subpart W no longer applies at the beginning of 
closure and further defines when closure begins. The following response 
is provided in the interest of further clarifying this issue.
    As described in the response to the previous comment, the EPA and 
the NRC entered into an MOU in 1991, after industry efforts to stay the 
implementation of subpart T, due, in part, to the fact that the 
requirement to complete closure of impoundments was unrealistically 
stringent. As part of the MOU, the EPA rescinded subpart T and modified 
its UMTRCA standards at 40 CFR 192.32 to address activities conducted 
during closure, including allowing placement of decommissioning wastes 
in non-operating impoundments. The EPA and the NRC agreed that such 
activities can, for the most part, be

[[Page 5171]]

conducted and a final cover installed within seven years of the end of 
operations. Similar timeframes should be possible for non-conventional 
impoundments, which are likely to be removed altogether. We note that 
both 40 CFR 192.32(a)(3) and 40 CFR part 40, Appendix A were modified 
and require that closure take place ``as expeditiously as practicable 
considering technological feasibility.'' They further state that such 
placement of wastes during closure will not be approved if it would 
cause delays in emplacement of the final radon barrier to meet the 
disposal requirements. The MOU did not address Subpart W because 
Subpart W does not apply during closure.
    The Agency has no plans to reinstate subpart T, although EPA is not 
precluded from doing so (40 CFR 261.226). Nor is the final rule 
extending the scope of Subpart W to cover closure activities. While 
this does leave a period of time when conventional and non-conventional 
impoundments are more likely to have increased radon emissions because 
they are not managed as they would be during operations, such a period 
is necessary to facilitate final closure activities. However, 
``dewatering'' tailings for decades, particularly in the arid West, is 
certainly not consistent with the seven-year period envisioned by both 
the EPA and the NRC. Most conventional tailings are emplaced using the 
phased disposal method. To avoid extended dewatering periods, sites may 
consider using the continuous disposal method, in which tailings are 
dewatered before emplacement and immediately covered. Regardless of the 
method of emplacement, we emphasize the importance of timely closure in 
achieving the safe end state of these sites, and encourage the NRC and 
NRC Agreement States to give appropriate attention to controlling radon 
emissions during closure activities.
    Comment: Some commenters expressed concern that impoundments are 
not being closed in accordance with closure plans, because the plans do 
not exist, milestones are absent or unclear, or milestones are not 
being enforced. One commenter states that the EPA should not consider 
an impoundment in closure until such plans are incorporated into the 
facility license. Another commenter recommends that we amend 40 CFR 
part 192 to include a provision that the EPA will verify the existence 
of a closure plan. Several commenters offer specific comments related 
to the White Mesa and Cotter sites and what they perceive as a lack of 
closure plans.
    Response: Activities related to closure or closure plans are beyond 
the scope of this rulemaking and the EPA is under no obligation to 
respond to comments on that topic. However, one purpose of this 
rulemaking was to clarify at what point Subpart W no longer applies to 
the management of uranium byproduct material or tailings. This final 
rule specifies that an approved reclamation plan is a prerequisite for 
entering closure, thereby removing a unit managing uranium byproduct 
material or tailings from the jurisdiction of Subpart W. The response 
below is provided in the interest of clarity in conveying the 
provisions of the final rule. The EPA does not require, review, approve 
or enforce reclamation or closure plans.
    As noted by one commenter, closure plans with milestones are 
required under 40 CFR part 192 and 10 CFR part 40, Appendix A. Closure 
plan requirements, closure activities and revisions to part 192 are not 
within the scope of this Subpart W rulemaking. The EPA typically does 
not see closure plans when reviewing construction applications under 40 
CFR part 61, subpart A. The NRC or the Agreement State is responsible 
for enforcement of reclamation or closure plans. The Cotter site ceased 
operations several years ago, no longer has an operating license and is 
therefore no longer subject to the requirements of Subpart W. The site 
is currently a Superfund site and is conducting activities under a 
decommissioning license from the State of Colorado.
    The final rule includes a definition of ``final closure'' that 
specifies notification that the impoundment in question is being 
managed according to the requirements and milestones in the approved 
reclamation plan. This should provide clarity when determining whether 
an impoundment is in closure, and whether Subpart W still applies.
    Comment: A few commenters took the opposite view of that addressed 
earlier in this section. These commenters wish us to clarify that the 
period of operations for either a conventional or non-conventional 
impoundment only extends to the management of uranium byproduct 
material or tailings produced by the concentration or extraction of ore 
processed primarily for its source material content (which may include 
the commercial management of such wastes produced at other facilities), 
and not to the management of wastes (byproduct material or otherwise) 
generated during closure or decommissioning activities.
    Response: The final rule clarifies that Subpart W does not apply 
during closure activities, and further defines when final closure 
begins. As described above in this section, this is essentially the 
position agreed to in the 1991 MOU between the EPA and the NRC. Both 40 
CFR 192.32(a)(3) and 10 CFR part 40 Appendix A, Criterion 6(A) provide 
for the use of impoundments while they are undergoing closure. However, 
impoundments that are used to manage uranium byproduct material or 
tailings generated during closure or remediation activities, while 
remaining open to manage operational wastes, would continue to fall 
under Subpart W until they formally enter the closure process and 
implement the approved reclamation plan for that impoundment. The 
definition of ``final closure'' adopted in the final rule makes clear 
that Subpart W does not apply to impoundments that are being managed 
under an approved reclamation plan.
    In addition to the use of an impoundment for wastes generated 
during closure or remediation activities, NRC regulations also provide 
for waste from other sources to be emplaced in the impoundment during 
the closure process (10 CFR part 40, Appendix A, Criterion 6(A)(3)). 
Approval of such emplacement requires a license amendment and must not 
delay complete closure of the impoundment. Subpart W does not apply to 
such authorized emplacements while the impoundment is undergoing 
closure because the unit is subject to an approved reclamation plan 
and, therefore, no longer operating. Depending on the terms of the 
license amendment, authorized emplacements at impoundments may include 
waste from ISL sites, which are not expected to construct permanent 
impoundments, thereby facilitating the overall goal of limiting the 
number of small disposal sites. Authorization to allow emplacement of 
waste from other sources during the closure process must be reflected 
in both the facility license and the applicable reclamation plan.
    Comment: One commenter disagreed with comments described earlier 
and pointed out that maintaining impoundments under Subpart W 
jurisdiction while they are undergoing closure may cause facilities to 
be out of compliance with the restriction on the number of conventional 
impoundments. The commenter posits that this situation could arise if a 
facility opened a new conventional impoundment for operational uranium 
byproduct material or tailings, while having another one in operation 
and one in closure (or multiple impoundments in closure). To avoid 
compliance issues, the commenter explained that facilities may have to

[[Page 5172]]

defer opening new impoundments, which could lead to temporary shutdown 
of the facility's processing operations if there is no outlet for the 
wastes. The commenter specifically notes that non-conventional 
impoundments may continue in operation when conventional impoundments 
are in closure.
    Response: We did not propose to extend the scope of Subpart W to 
apply during closure activities and thus did not open this issue as 
part of our review under CAA section 112(q). Also, we are neither 
finalizing such an extension of applicability, nor limiting the number 
of non-conventional impoundments that may be in operation at any one 
time.
    Comment: Several commenters stated that definitions in or proposed 
for Subpart W are inconsistent with the NRC's definitions in 10 CFR 
part 40 (and Appendix A). For example, two commenters state that 
``[t]he definition of Operation conflicts with existing regulations, 
specifically those in 10 CFR part 40 Appendix A following the 
rescission of 40 CFR part 61 Subpart T.'' These commenters also suggest 
that we look to the Appendix A definition of ``closure'' and they note 
that the closure period is tied to the ``end of milling operations'' in 
Criterion 6.
    One commenter requests clarification of the term ``day that final 
closure begins,'' which the commenter believes has never been 
adequately explained. Another commenter requests clarification on the 
steps that must take place for closure to begin. Commenters also stated 
that we did not include non-conventional impoundments in the definition 
of operation.
    Response: It is important to make the distinction between closure 
of an impoundment and closure of a facility. Subpart W applies to 
impoundments that are operating. An individual impoundment may enter 
and complete the closure process, thus removing it from Subpart W 
jurisdiction, while other impoundments and the facility continue to 
operate. When the facility (site) itself enters the closure process, 
and is no longer operating (and generating uranium byproduct material 
or tailings), impoundments will also be managed according to the 
overall site closure plan. Tying Subpart W to the ``end of milling 
operations'' in NRC regulations, as suggested by the two commenters, 
would essentially preclude the closure of individual impoundments until 
overall site closure begins. This is likely contrary to the commenters' 
intentions. We also note that the NRC definition of ``closure'' cited 
by these commenters clearly refers to activities undertaken to close 
the entire site and is not directed specifically at impoundment 
closure.
    Additionally, commenters have misinterpreted our proposal. The 
Agency does not intend to apply Subpart W to impoundments that have 
entered the closure process. The proposed modification of the 
definition of ``operation,'' which we are adopting in the final rule, 
clarifies that impoundments that have not yet entered closure remain 
subject to Subpart W, even if the material they are receiving is not 
newly-generated uranium byproduct material or tailings (``new 
tailings'' in the original). This also makes the definition more 
consistent with those in 40 CFR part 192 and 10 CFR part 40, Appendix 
A. See the proposed rule at 79 FR 25405, May 2, 2014. To further 
clarify this situation, the final rule includes a definition of ``final 
closure'' specifying that closure begins upon written notification that 
the impoundment is being managed according to the requirements and 
milestones in the approved reclamation plan for that impoundment.
    This definition of ``final closure'' adopts a suggestion provided 
by one commenter. The commenter proposed tying ``closure period'' to a 
written notification from the licensee that the impoundment is no 
longer being used for emplacement of tailings or for evaporative or 
holding purposes, and is also no longer on standby for such purposes. 
The commenter suggests that it would be useful to explicitly address 
both conventional and non-conventional impoundments in the definitions, 
as there may be situations where non-conventional impoundments continue 
to operate when conventional impoundments are in closure. We are also 
adopting this suggestion in the definition of ``final closure.''
    Adding this language should eliminate some uncertainty regarding 
impoundment status. This uncertainty is reflected in a statement by the 
same commenter regarding the White Mesa Mill. In providing information 
about the different impoundments, the commenter notes that ``. . . Cell 
3 could be considered to have already commenced the closure process'' 
(emphasis added). The written notification requirement will help 
eliminate such ambiguous situations. There should be no question as to 
whether an impoundment is undergoing closure, and similarly no 
ambiguity regarding the applicability of Subpart W.
    Regarding the perceived conflicts with NRC regulations, we do not 
see such a conflict, and note that the definition of ``operation'' in 
existing and proposed Subpart W is substantively identical to and 
served as the basis for that in 10 CFR part 40, Appendix A (we note the 
NRC's statement in its proposal that ``the definition of operations is 
in conformance with the definition of `operational' in the proposed EPA 
amendment to [40 CFR part 192] subpart D and in 40 CFR part 61, subpart 
W'' (58 FR 58659, November 3, 1993). The commenters did not suggest 
that the NRC's definition is in conflict with its own regulations. 
Further, the same definition is used in 40 CFR 192.31(p). As noted 
above, we are also adding a definition of ``final closure'' in the 
final rule. This will provide additional clarity as to what steps the 
operator must take to remove an impoundment from the jurisdiction of 
Subpart W while remaining consistent with the definitions in 10 CFR 
part 40 and 40 CFR part 192. The definition of final closure explicitly 
addresses conventional impoundments, non-conventional impoundments and 
heap leach piles.
    The phrase ``day that final closure begins'' was included in the 
original promulgation of Subpart W in 1986 (51 FR 34056, September 14, 
1986). ``Final closure'' is a term defined under RCRA hazardous waste 
regulations in 40 CFR 260.10. ``Final closure'' in that context refers 
to the closure of all hazardous waste management units at a site, and 
is distinguished from ``partial closure,'' which refers to closure of 
individual units. However, as the term is used in Subpart W, and as it 
is being adopted in the final rule, it refers to individual 
impoundments, not the entire site (so is more like ``partial closure'' 
in the RCRA context). Subpart W differs in this respect from 40 CFR 
part 192 and 10 CFR part 40, Appendix A, which are both also concerned 
with closure of the overall site. We also note that, as described 
earlier, the definition of ``operations'' in Subpart W served as the 
basis for corresponding definitions in 40 CFR part 192 and 10 CFR part 
40, Appendix A, and this phrasing has also been adopted in and provides 
consistency with those regulations. We did not propose to change it and 
we are not finalizing any changes.
    Comment: The State of Utah commented on the status of liners at two 
of the facilities regulated by the State under its Subpart W 
delegation. The conventional impoundment at the Shootaring Canyon Mill 
was constructed in 1981 and ``was not required to be constructed in 
accordance with'' the requirements of 40 CFR 192.32(a). However, the 
State will require the liner to be upgraded if the mill goes back into 
production. The Shootaring Canyon Mill operated for

[[Page 5173]]

only a short period and has been in standby for nearly 35 years. The 
State also addresses Cell 1 at the White Mesa Mill, which is a non-
conventional impoundment also constructed in 1981. The State has not 
considered this impoundment to be subject to Subpart W and believes 
that EPA must conduct a cost-benefit analysis if the liner is required 
to be upgraded.
    Response: Comments indicate that some stakeholders have not always 
clearly understood the true scope of the 1989 Subpart W rulemaking. The 
1989 rulemaking revised the approach taken in 1986, which required 
impoundments existing at that time to cease operations by December 31, 
1992 unless they could receive an exemption or extension (51 FR 34066). 
These impoundments were not required by Subpart W to meet the 
requirements of 40 CFR 192.32(a). The 1989 rulemaking lifted the 
operating restriction on older impoundments, but also removed the 
exemption from the requirements of 40 CFR 192.32(a) (54 FR 51680). This 
provision, promulgated as 40 CFR 61.252(c), explicitly addressed the 
exemption for impoundments constructed prior to the promulgation of 40 
CFR part 192 and established that all impoundments used to manage 
uranium byproduct material or tailings became subject to the liner 
requirements in 40 CFR 192.32(a) when the 1989 rule became effective, 
regardless of when they were constructed. These liner requirements have 
remained in place because CAA section 112(q) explicitly retains 
standards that were in effect before the date of enactment of the CAA 
Amendments of 1990, unless and until the EPA revises them.
    The two impoundments identified by the State of Utah are both 
required to comply with the liner requirements in 40 CFR 192.32(a)(1), 
and by extension 40 CFR 264.221. The standby status of the Shootaring 
Canyon Mill makes no difference in this regard. We understand that some 
stakeholders did not view the 1989 rulemaking as applicable to liquid 
(non-conventional) impoundments. This final rule clarifies that non-
conventional impoundments did fall under the 1989 rule and are also 
subject to the requirements in 40 CFR 192.32(a)(1). We note that 
Denison Mines, the previous owner of the White Mesa Mill, stated in its 
response to the EPA's section 114 request for information that Cell 1 
meets the requirements of 40 CFR 264.221(a).
    Comment: Many commenters objected to the proposal to eliminate the 
phrase ``as determined by the Nuclear Regulatory Commission'' from 
provisions related to review of the impoundment construction 
requirements in 40 CFR 192.32(a)(1). Commenters in general argued that 
eliminating the phrase ``as determined by the Nuclear Regulatory 
Commission'' would result in unnecessary dual regulation if both the 
EPA and the NRC need to review and approve construction applications, 
with limited if any benefit. One commenter suggests this will have 
significant cost implications that were not considered during the 
rulemaking. Another commenter questions how disagreements between the 
agencies will be resolved, and suggests that appeals will be 
``inappropriately complicated''.
    A number of these commenters asserted that our proposal was 
contrary to the legal framework established by Congress for management 
of byproduct material as defined in Section 11e.(2) of the AEA. 
Commenters cite to the framework in Section 275 of the AEA, which 
directs the EPA to establish standards for management of byproduct 
material and which gives the NRC sole authority over implementation and 
enforcement of the EPA's standards through its licensing process (one 
commenter cites Title 42 of the United States Code, Section 2022(d) 
rather than Section 275 of the AEA). Several commenters refer 
specifically to that section's statement that ``no permit issued by the 
Administrator is required . . . for the processing, possession, 
transfer, or disposal of byproduct material, as defined in section 
11e.(2) to this subsection.'' Another commenter suggests that the EPA 
is attempting to expand its role by improperly assuming or duplicating 
the NRC's responsibilities.
    One commenter does not make these specific statutory references, 
but more generally criticizes the EPA for ``grossly inefficient, dual 
regulation'' that is ``inconsistent with efficient regulatory 
practices'' and goes against previous efforts by the two agencies to 
avoid such situations, as illustrated by the EPA's rescission of 40 CFR 
part 61, subparts I and T. The commenter suggests that Subpart W could 
also be rescinded, and notes that the EPA's separate rulemaking related 
to 40 CFR part 192 may be used to incorporate elements of Subpart W as 
needed.
    We also received some comments in support of the proposal to remove 
the phrase ``as determined by the Nuclear Regulatory Commission.'' One 
commenter believes this is a welcome clarification that the EPA is 
administering the NESHAP program. Another commenter notes that it is 
not unusual for an industry to be regulated under more than one statute 
or agency. A third commenter points out that this situation has existed 
for several decades. A fourth commenter agrees and cites the EPA 
approvals under 40 CFR part 61, subpart A, as well as the division of 
responsibilities at the state level in Utah as they relate to the White 
Mesa Mill.
    Response: The EPA disagrees that the change will be burdensome to 
licensees or create additional barriers to regulatory approval. We 
proposed this change to be consistent with the proposal to narrow the 
reference to the impoundment engineering and construction requirements. 
As explained in the preamble to the proposed rule, the requirements at 
40 CFR 61.252(b) and (c) required compliance with 40 CFR 192.32(a) (79 
FR 25406). However, we focus the Subpart W requirements on the 
impoundment design and construction requirements found specifically at 
40 CFR 192.32(a)(1). The remainder of 40 CFR 192.32(a) goes beyond this 
limited scope by including requirements for ground-water detection 
monitoring systems and closure of operating impoundments. These other 
requirements, along with all of the part 192 standards, are implemented 
and enforced by the NRC through its licensing requirements for uranium 
recovery facilities at 10 CFR part 40, Appendix A. It is appropriate 
for compliance with those provisions to be solely determined by the 
NRC. However, when referenced in Subpart W, the requirements in 40 CFR 
192.32(a)(1) would also be implemented and enforced by the EPA as the 
regulatory authority administering Subpart W under its CAA authority. 
Therefore, we revised 40 CFR 61.252(b) and (c) to specifically define 
which portions of 40 CFR 192.32(a) are applicable to Subpart W. Section 
61.252(b) is re-numbered as 61.252(a)(2) and section 61.252(c) is 
incorporated into 61.252(a)(1) in the final rule.
    The comments confirm that there is a misimpression that this 
reference to the NRC precluded the EPA from reviewing applications for 
compliance with 40 CFR 192.32(a)(1) in its pre-construction and 
modifications reviews under 40 CFR 61.07 and 61.08. That is an 
incorrect interpretation of the 1989 rule. To the contrary, in 
promulgating the 1989 rule, we stated ``Mill operators will not be 
allowed to build any new mill tailings impoundment which does not meet 
this work practice standard. EPA will receive information on the 
construction of new impoundments through the requirements for EPA to 
approve of new construction under 40 CFR part 61, subpart A'' (54 FR 
51682). The referenced ``work practice standard'' includes the 
requirement for

[[Page 5174]]

conformance with 40 CFR 192.32(a). We are eliminating the reference to 
the NRC to clarify that the EPA is an approval authority for the 
impoundment engineering and construction provisions in 40 CFR 
192.32(a)(1). This change will have no effect on the licensing 
requirements of the NRC or its regulatory authority under UMTRCA to 
implement the part 192 standards through its licenses.
    Commenters' references to AEA Section 275 as limiting our authority 
are incorrect. The commenters have overlooked a salient point, which is 
that the Subpart W rulemaking is being undertaken pursuant to our CAA 
authority, not under the AEA. Another relevant provision in Section 
275, 275e (42 U.S.C. 2022(e)), states: ``Nothing in this Act applicable 
to byproduct material, as defined in section 11e.(2) of this Act, shall 
affect the authority of the Administrator under the Clean Air Act of 
1970, as amended, or the Federal Water Pollution Control Act, as 
amended.'' The Federal Water Pollution Control Act is also known as the 
Clean Water Act.
    Further, commenters who cited the prohibition on EPA permitting 
neglected to note the context for this provision and the specificity of 
the language regarding the standards of general application to be 
developed by the EPA. AEA section 275b.(2) reads as follows: ``Such 
generally applicable standards promulgated pursuant to this subsection 
for nonradiological hazards shall provide for the protection of human 
health and the environment consistent with the standards required under 
subtitle C of the Solid Waste Disposal Act, as amended, which are 
applicable to such hazards: Provided, however, That no permit issued by 
the Administrator is required under this Act or the Solid Waste 
Disposal Act, as amended, for the processing, possession, transfer, or 
disposal of byproduct material, as defined in section 11e.(2) to this 
subsection'' (emphasis in original). Thus, Congress required the EPA's 
standards to be consistent with standards applicable to nonradiological 
hazardous waste (subtitle C of the Solid Waste Disposal Act, better 
known as the Resource Conservation and Recovery Act, or RCRA) in lieu 
of the Agency exercising permitting authority under either the AEA or 
RCRA. The EPA is not contravening this restriction by exercising 
regulatory authority under the CAA. Responses to other comments on our 
legal authorities for this action may be found in Section IV.A.2.
    Regarding the view of appropriate and efficient regulation, our 
action will not have such far-reaching consequences. The EPA and the 
NRC have not examined the prospect of rescinding Subpart W. As with the 
rescission of 40 CFR part 61, subparts I and T, and in accordance with 
CAA section 112(d)(9), the EPA would need to determine that the NRC's 
regulatory program will protect public health with an ample margin of 
safety. The EPA's separate rulemaking under 40 CFR part 192 
specifically addresses ground water protection at ISL facilities.
    Comment: Several commenters addressed the definition of ``uranium 
byproduct material or tailings'' in Subpart W. Commenters generally 
raised the distinction between ``tailings'' and ``byproduct material'' 
under the AEA as germane to the scope of this rulemaking. One commenter 
suggests that the historical focus on conventional mill tailings 
impoundments (or ``piles'') is linked to the CAA, and that we are 
impermissibly re-defining non-tailings byproduct material as 
``tailings'' as a means to address them under the CAA. Another 
commenter noted the following in reference to the AEA definition: ``All 
tailings are byproduct material, but not all byproduct materials are 
tailings.'' A third commenter asks for clarification on how restoration 
fluids may be considered byproduct material. Several commenters 
suggested that we adopt the NRC's definition in 10 CFR 40.4 as a means 
to improve clarity and consistency.
    Another commenter raised a question regarding wastes at uranium 
recovery facilities that are not derived from ores. The commenter 
stated that such wastes may derive from ``alternate feed'' materials 
that contain sufficient uranium to make processing worthwhile (e.g., 
tailings from other mineral extraction operations), or could include 
wastes placed directly into conventional impoundments because they are 
physically or chemically similar to the material already being managed.
    Response: Although we received suggestions to adopt the AEA's and 
the NRC's definition of byproduct material, we did not propose to 
revise the definition of uranium byproduct material or tailings. CAA 
section 112(q) explicitly retains standards such as Subpart W that were 
in effect before the date of enactment of the CAA Amendments of 1990, 
so the existing definition of uranium byproduct material or tailings 
remains unless or until the EPA revises it. Because we did not propose 
to revise the definition of uranium byproduct material or tailings, we 
did not open it for comment. The EPA first defined the term ``uranium 
byproduct material or tailings'' in 1986 and has generally used the 
term ``tailings'' in Subpart W for simplicity. This rulemaking 
clarifies the scope of the EPA's term ``uranium byproduct material or 
tailings'' and provides reassurance that it is not in conflict with 
NRC's definitions. The following discussion is provided for 
informational purposes to further clarify this issue.
    We note that the EPA has clear authority to promulgate definitions 
under the CAA as it deems appropriate and is not limited to the AEA's 
definition of ``byproduct material'' or the NRC's definition in 10 CFR 
40.4. The EPA's definition identifies the scope of material covered by 
the Subpart W regulations and does not preempt the NRC's AEA authority. 
See Section IV.A.2 for more discussion of legal authorities as they 
relate to this issue.
    The definition of ``uranium byproduct material or tailings'' in 
Subpart W, as it was promulgated in 1989 and not modified by this rule, 
establishes that Subpart W broadly addresses radon emissions from 
operating structures used to manage wastes produced during and 
following the concentration or extraction of uranium from ore processed 
primarily for its source material content. The EPA acknowledges that 
the definition of ``uranium byproduct material or tailings,'' as 
originally promulgated in 1989, may not wholly conform with the common 
understanding of ``tailings.'' However, the scope and applicability of 
Subpart W is determined by the regulatory definition of ``uranium 
byproduct material or tailings,'' not the common understanding of 
tailings. Subpart W applies to the structures at uranium recovery 
facilities that are used to manage or contain ``uranium byproduct 
material or tailings'' during and following the processing of uranium 
ores. Common names for these structures may include, but are not 
limited to, impoundments, tailings impoundments, tailings piles, 
evaporation or holding ponds, and heap leach piles. However, the name 
itself is not important for determining whether Subpart W requirements 
apply to that structure; rather, applicability is based on what these 
structures contain. To clarify any potential confusion created by the 
Subpart W definition, any references to ``uranium byproduct material'' 
or ``tailings'' are now references to ``uranium byproduct material or 
tailings.'' These changes reaffirm the scope of Subpart W and are not 
substantive.
    The defined scope of materials subject to Subpart W becomes more 
meaningful when one considers the current

[[Page 5175]]

dominance of ISL in uranium recovery. At these sites, where 
conventional impoundments are not present, non-conventional 
impoundments managing uranium byproduct material or tailings are the 
most significant potential source of radon during operations. Although 
we do not generally expect non-conventional impoundments to be as large 
a source of potential emissions as conventional impoundments, non-
conventional impoundments manage uranium byproduct material or tailings 
and emit or have the potential to emit sufficient radon that it is 
appropriate for the EPA to address them under Subpart W.
    The designation of restoration fluids as uranium byproduct material 
or tailings is consistent with the approach taken by the NRC. See Staff 
Requirements Memorandum--SECY-99-013, ``Recommendation on Ways to 
Improve the Efficiency of NRC Regulation at In Situ Leach Uranium 
Recovery Facilities,'' July 26, 2000.
    It is not necessary for us to explicitly address waste not 
resulting from the concentration or extraction of ores because Subpart 
W applies to impoundments, both conventional and non-conventional, that 
are used to manage uranium byproduct material or tailings. Such 
impoundments that also contain non-ore wastes continue to be subject to 
Subpart W. It is unlikely that an operator would construct impoundments 
for the sole purpose of managing wastes that do not derive from the 
processing of ores. As explained in Section IV.E.2, the purpose of 
Subpart W is to control radon emissions from sources containing uranium 
byproduct material or tailings at uranium recovery facilities. If an 
impoundment does not contain uranium byproduct material or tailings, it 
is not subject to the requirements of Subpart W. If construction of 
such impoundments is planned, they can be identified and their status 
can be addressed during the construction application review under 
subpart A.
    Comment: Commenters requested clarification regarding whether 
liquids in impoundments contain byproduct material or are byproduct 
material. One commenter asked us to clarify that solids and liquids in 
impoundments are byproduct material.
    Response: Subpart W applies to conventional and non-conventional 
impoundments to the extent they are used to manage uranium byproduct 
material or tailings, with the primary concern being the potential to 
emit radon. The uranium byproduct material or tailings may be in 
solution or suspension in liquids that are discharged to these 
impoundments, or in sediments after settling out from the liquids.

V. Summary of Environmental, Cost and Economic Impacts

    As discussed earlier, uranium recovery activities are carried out 
at several different types of facilities. We are revising Subpart W 
based on how uranium recovery facilities manage uranium byproduct 
materials during and after the processing of uranium ore at their 
particular facility. As discussed in Sections III and IV, we are 
establishing GACT-based requirements for three types of affected 
sources at uranium recovery facilities: (1) Conventional impoundments; 
(2) non-conventional impoundments; and (3) heap leach piles.
    For purposes of analyzing the impacts of the final rule, we assumed 
that approximately five conventional milling facilities, 50 ISL 
facilities (although this is only a projection since only 12 are fully 
licensed) and one heap leach facility, each with at least one regulated 
impoundment, are subject to the final Subpart W. The following sections 
present our estimates of the final rule's air quality, cost and 
economic impacts. For more information, please refer to the Economic 
Impact Analysis (EIA) report that is included in the public docket for 
this final rule (EPA-HQ-OAR-2008-0218).

A. What are the air quality impacts?

    The requirements in this final rule should eliminate or reduce 
radon emissions at all three types of affected sources. The GACT-based 
standards being established by this action are based on control 
technologies and management practices that have been used at uranium 
recovery facilities for the past twenty or more years. These standards 
will minimize the amount of radon that is released to the air by 
keeping the impoundments wet or covered with soil and/or by limiting 
the area of exposed uranium byproduct material or tailings.

B. What are the cost and economic impacts?

    Table 5 presents a summary of the unit cost (per pound of 
U3O8) for implementing each GACT-based standard 
at each of the three types of uranium recovery facilities. Because the 
requirements for liners are not attributable to Subpart W, but are 
required by other regulations, the only costs attributable to this 
rulemaking are related to maintaining liquids in non-conventional 
impoundments. In addition to presenting the GACT costs individually, 
Table 5 presents the total unit cost to implement all relevant GACT-
based standards at each type of facility. For example, the table shows 
that conventional mills will have both conventional impoundments and 
non-conventional impoundments, and will also be required to maintain 
saturation in the non-conventional impoundments.

                              Table 5--Final GACT Standards Costs per Pound of U3O8
----------------------------------------------------------------------------------------------------------------
                                                                               Unit cost ($/lb U3O8)
                                                                 -----------------------------------------------
                                                                   Conventional
                                                                       mills      ISL facilities    Heap leach
----------------------------------------------------------------------------------------------------------------
GACT--Double Liners for Conventional Impoundments *.............           $1.04  ..............  ..............
GACT--Double Liners for Non-conventional Impoundments *.........            1.04           $3.07           $0.22
GACT--Maintaining Non-conventional Impoundment Sediments 100%              0.015           0.026          0.0013
 Saturated......................................................
GACT--Liners for Heap Leach Piles *.............................  ..............  ..............            2.01
GACTs--Total for All Four.......................................            2.09            3.09            2.24
Baseline Facility Costs ** (EIA Section 6.2)....................           55.18           51.31           45.06
Baseline Facility Costs ***.....................................           51.56           52.49           46.08
----------------------------------------------------------------------------------------------------------------
* Liners required by 40 CFR part 192.
** Based on Price of U3O8 at $55/lb.
*** Based on Price of U3O8 at $65/lb (used in proposed rule).

[[Page 5176]]

    A reference facility for each type of uranium recovery facility is 
developed and described in Section 6.2 of the EIA, including the base 
cost estimate to construct and operate each of the three types of 
reference facilities. For comparison purposes, the unit cost (per pound 
of U3O8) of the three uranium recovery reference 
facilities is presented at the bottom of Table 5. In developing the 
baseline cost, it was assumed that the price of 
U3O8 is $55 per pound. At that price, baseline 
facility costs increase somewhat for the conventional mill because the 
cost of financing (i.e., interest) also increases as revenues are 
lower. The baseline cost for a conventional mill actually exceeds the 
$55/lb, which suggests that the mill cannot operate profitably. 
Baseline costs at $65 per pound, which was used to support the proposed 
rule, are also shown for comparison. This illustrates the sensitivity 
of facility cost to market price, which is more significant than the 
cost of implementing the GACT-based standards.
    Based on the information in Table 5, the four GACT-based standards 
represent about 4%, 6%, and 5% of the baseline cost (per pound of 
U3O8) at conventional, ISL, and heap leach 
uranium recovery facilities, respectively. The baseline costs were 
estimated using recently published cost data for actual uranium 
recovery facilities. For the model conventional mill, we used data from 
the recently licensed new mill at the Pi[ntilde]on Ridge project in 
Colorado. For the model ISL facility, we used data from two proposed 
new facilities: (1) The Centennial Uranium project in Colorado; and (2) 
the Dewey-Burdock project in South Dakota. The Centennial project is 
expected to have a 14- to 15-year production period, which is a long 
duration for an ISL facility, while the Dewey-Burdock project is 
expected to have a shorter production period of about 9 years, which is 
more representative of ISL facilities. For the heap leach facility, we 
used data from the proposed Sheep Mountain project in Wyoming.
    Baseline costs for conventional impoundment liner construction \25\ 
will remain the same, since the final rule does not impose additional 
requirements. Liners meeting the requirements at 40 CFR 192.32(a)(1) 
are already mandated by other regulations and were mandated by the 1989 
rule and, therefore, are built into the baseline cost estimate. As a 
result, there are no costs (or benefits) resulting from the inclusion 
of these requirements in the final rule.
---------------------------------------------------------------------------

    \25\ These liner systems (conventional, non-conventional and 
heap leach piles) are already required by 40 CFR 192.32(a)(1), 
which, as explained above, are requirements promulgated by the EPA 
under UMTRCA that are incorporated into NRC regulations and 
implemented and enforced by the NRC through its licensing 
requirements. Therefore, we are not placing any additional liner 
requirements on facilities or requiring them to incur any additional 
costs to build their conventional or non-conventional impoundments 
or heap leach piles above and beyond what an owner or operator of 
these impoundments must already incur to obtain an NRC license. 
Therefore, there are no projected costs (or benefits) beyond the 
baseline resulting from the inclusion of these requirements in 
Subpart W.
---------------------------------------------------------------------------

    The average cost to construct one of these impoundments is $13.8 
million. We estimate that this cost is less than 2% of the total 
baseline costs to construct and operate a conventional mill, per pound 
of U3O8 produced.
    We have estimated that for an average 80-acre non-conventional 
impoundment the average cost of construction of an impoundment is $24.7 
million. Requiring impoundments to comply with the liner requirements 
in 40 CFR 192.32(a)(1) will contain the uranium byproduct material and 
reduce the potential for ground water contamination. The only economic 
impact attributable to the final rule is the cost of complying with the 
new requirement to maintain liquids such that solids in the non-
conventional impoundments are not visible above the liquid level during 
operation and standby. As explained in Section IV.B.3. of this 
preamble, as long as solid materials are maintained in a saturated 
state in the non-conventional impoundments the effective radon 
emissions from the ponds are reduced by approximately 95%. In order to 
maintain a liquid surface above the sediments within a pond, it is 
necessary to replace the water that is evaporated from the pond. 
Depending on the source of water chosen, we estimate that this 
requirement will cost owners or operators of non-conventional 
impoundments between $2,909 and $37,527 per year.\26\ This value also 
varies according to the size of the non-conventional impoundment, up to 
80 acres, and the location of the impoundment. Evaporation rates vary 
by geographic location. The requirement to maintain a liquid surface 
above solid materials in the ponds is estimated to cost less than $0.03 
per pound of uranium produced.
---------------------------------------------------------------------------

    \26\ These figures are higher than those estimated for the 
proposed rule. We received information during the comment period 
that resulted in an increase in the estimated cost of obtaining 
makeup water, so the final rule requirement of 100% saturation is 
still lower than the proposed requirement to maintain one meter of 
liquid, using the same base water costs.
---------------------------------------------------------------------------

    Designing and constructing heap leach piles to meet the 
requirements at 40 CFR 192.32(a)(1) will minimize the potential for 
leakage of uranium enriched lixiviant into the ground water. 
Specifically, this will require that a double liner, with drainage 
collection capabilities, be provided under heap leach piles. Baseline 
costs for heap leach pile liner construction will remain the same, 
since the final rule does not impose additional requirements. Liners 
meeting the requirements at 40 CFR 192.32(a)(1) are already mandated by 
other regulations and, therefore, built into the baseline cost 
estimate. Therefore there are consequently no costs (or benefits) 
resulting from the inclusion of these requirements in Subpart W. 
Baseline costs for construction will be essentially the same as for 
conventional impoundments. Since the liner systems are equivalent to 
the systems used for conventional and non-conventional impoundments, we 
have been able to estimate the average costs associated with the 
construction of heap leach pile impoundments that meet the liner 
requirements we are proposing, and compare them to the costs associated 
with the total production of uranium produced by the facility. The 
average cost of constructing such an impoundment is estimated to be 
approximately $12.6 million. The costs of constructing this type of 
liner system are less than 5% of the estimated total baseline costs of 
a heap leach facility.
    In summary, we estimate that for conventional impoundments there 
will be no additional costs incurred through this proposed rule. For 
non-conventional impoundments we estimate that the additional costs 
incurred by this proposed rule will be to maintain a layer of liquid 
above solid materials in each non-conventional impoundment, and we have 
estimated those costs between approximately $2,909 and $37,527 per 
year, which represents less than $0.03 per pound of 
U3O8 produced. For heap leach piles, no 
additional costs will be incurred.

C. What are the non-air environmental impacts?

    Water quality will be maintained by implementation of this final 
rule. This final rule does contain requirements (by reference) related 
to water discharges and spill containment. In fact, the liner 
requirements cross referenced at 40 CFR 192.32(a)(1) will significantly 
decrease the possibility of contaminated liquids leaking from 
impoundments into ground water (which can be a

[[Page 5177]]

significant source of drinking water). Section 192.32(a)(1) includes a 
cross-reference to the surface impoundment design and construction 
requirements of hazardous waste surface impoundments regulated under 
RCRA, found at 40 CFR 264.221. Those requirements state that the 
impoundment shall be designed, constructed and installed to prevent any 
migration of wastes out of the impoundment to the adjacent subsurface 
soil or ground water or surface water at any time during the active 
life of the impoundment. There are other requirements in 40 CFR 264.221 
for the design and operation of the impoundment, and these include 
construction specifications, slope requirements, sump and liquid 
removal requirements. These liner systems for conventional and non-
conventional impoundments and heap leach piles are already required by 
40 CFR 192.32(a)(1), which, as explained above, are requirements 
promulgated by the EPA under UMTRCA that are incorporated into NRC 
regulations and implemented and enforced by the NRC through their 
licensing requirements. Therefore, we are not placing any additional 
liner requirements on facilities or requiring them to incur any 
additional costs to build their conventional or non-conventional 
impoundments or heap leach piles above and beyond what an owner or 
operator of these impoundments must already incur to obtain an NRC 
license.
    Including a double liner in the design of all onsite impoundments 
that would contain uranium byproduct material or tailings will reduce 
the potential for groundwater contamination. Although the amount of the 
potential reduction is not quantifiable, it is important to take this 
into consideration due to the significant use of ground water as a 
source of drinking water.

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

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 OMB for review. The Executive Order (E.O.) defines ``significant 
regulatory action'' as one that is likely to result in a rule that 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.'' Any changes made in response to OMB recommendations have been 
documented in the docket for this action. The EPA prepared an economic 
analysis of the potential costs and benefits associated with this 
action. This analysis, ``Technical and Regulatory Support to Develop a 
Rulemaking to Modify the NESHAP Subpart W Standard for Radon Emissions 
from Operating Mill Tailings (Background Information Document and 
Economic Impact Analysis),'' Docket No. EPA-HQ-OAR-2008-0218, is 
available in the docket and summarized in Section V of this preamble. 
This action is not a significant economic action.

B. Paperwork Reduction Act (PRA)

    The information collection requirements in this rule have been 
submitted for approval to OMB under the PRA. The Information Collection 
Request (ICR) document prepared by the EPA has been assigned EPA ICR 
number 2464.02. You can find a copy of the ICR in the docket for this 
rule, and it is briefly summarized here. The information collection 
requirements are not enforceable until OMB approves them.
    The information to be collected for the rule is based on the 
requirements of the CAA. Section 114 authorizes the Administrator of 
the EPA to require any person who owns or operates any emission source 
or who is subject to any requirements of the Act to:

--Establish and maintain records
--Make reports, install, use, and maintain monitoring equipment or 
method
--Sample emissions in accordance with EPA-prescribed locations, 
intervals and methods
--Provide information as may be requested

    EPA's regional offices use the information collected to ensure that 
public health continues to be protected from the hazards of 
radionuclides by compliance with health based standards and/or GACT.
    The rule requires the owner or operator of a uranium recovery 
facility to maintain records that confirm that the conventional 
impoundment(s), non-conventional impoundment(s) and heap leach pile(s) 
meet the requirements in Sec.  192.32(a)(1). Included in these records 
are the results of liner compatibility tests and documentation that a 
layer of liquid above solid materials has been maintained in non-
conventional impoundments. This documentation should be sufficient to 
allow an independent auditor (such as an EPA inspector) to verify the 
accuracy of the determination made concerning the facility's compliance 
with the standard. These records must be kept at the mill or facility 
for the operational life of the facility and, upon request, be made 
available for inspection by the Administrator, or his/her authorized 
representative. The rule requires the owners or operators of operating 
non-conventional impoundments to submit digital photographs taken 
during the compliance inspections required in section 61.252(b). The 
recordkeeping requirements require only the specific information needed 
to determine compliance. We have taken this step to minimize the 
reporting requirements for small business facilities.
    The annual monitoring and recordkeeping burden to affected sources 
for this collection (averaged over the first three years after the 
effective date of the final rule) is estimated to be 6,693 hours with a 
total annual cost of $336,950 for the requirements related to 
documenting the liquid level in non-conventional impoundments, and a 
one-time expenditure of 460 hours and $32,890 to maintain records of 
impoundment design and construction. This estimate includes a total 
capital and start-up cost component annualized over the facility's 
expected useful life and a purchase of services component. We estimate 
that this total burden will be spread over 23 facilities that will be 
required to keep records.
    Burden is defined at 5 CFR 1320.3(b). An agency may not conduct or 
sponsor, and a person is not required to respond to, a collection of 
information unless it displays a currently valid OMB control number. 
The OMB control numbers for EPA's regulations in 40 CFR are listed in 
40 CFR part 9. When OMB approves this ICR, the Agency will announce 
that approval in the Federal Register and publish a technical amendment 
to 40 CFR part 9 to display the OMB control number for the approved 
information collection activities contained in this final rule.

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 whose company has less than 250 employees and is primarily 
engaged in leaching or beneficiation of uranium, radium or vanadium 
ores as defined by NAICS code 212291.
    The EPA has determined that small entities subject to the 
requirements of

[[Page 5178]]

this action are approximately 18 uranium recovery facilities that are 
currently operating or plan to operate in the future. The Agency has 
determined that the ten small businesses that own these facilities may 
experience an impact of less than 1% of total annual production costs, 
or less than $0.03 per pound of uranium produced. Details of this 
analysis are presented in Section 6 of the BID/EIA prepared to support 
this rulemaking (Docket No. EPA-HQ-OAR-2008-0218).

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. The final rule 
imposes no enforceable duty on any state, local or tribal governments 
or the private sector. Thus, this rule is not subject to the 
requirements of sections 202 or 205 of UMRA.
    This rule is also not subject to the requirements of section 203 of 
UMRA because it contains no regulatory requirements that might 
significantly or uniquely affect small governments because it contains 
no requirements that apply to such governments nor does it impose 
obligations upon them.

E. Executive Order 13132: Federalism

    This 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. None of 
the facilities subject to this action are owned and operated by State 
governments and nothing in the final rule will supersede State 
regulations. Thus, E.O. 13132 does not apply to this final rule.

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

    This action does not have tribal implications, as specified in 
Executive Order 13175. The action imposes requirements on owners and 
operators of specified area sources and not tribal governments. Thus, 
Executive Order 13175 does not apply to this action.
    The EPA notes, however, that several tribes or tribal groups 
expressed interest in this rulemaking due to the proximity of some of 
the facilities regulated under Subpart W to tribal lands. Consistent 
with the EPA Policy on Consultation and Coordination with Indian 
Tribes, the EPA consulted with tribal officials of the Ute Mountain Ute 
Tribe during development of this action. A summary of that consultation 
is provided in Docket No. EPA-HQ-OAR-2008-0218-0120.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866. This 
action's health and risk assessments are contained in Section IV.B.2 of 
this preamble and in the Background Information Document prepared to 
support this action (Docket No. EPA-HQ-OAR-2008-0218). The updated risk 
assessment described in Section IV.B.2 incorporated the risk 
coefficients from Federal Guidance Report (FGR) No. 13, ``Cancer Risk 
Coefficients for Environmental Exposure to Radionuclides,'' which 
includes age-averaged factors to convert radionuclide exposure (intake) 
to health risk. FGR 13 was developed subsequent to the risk assessment 
conducted to support the 1989 rulemaking, which relied upon factors 
applicable to adults. FGR 13 is undergoing revision.

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

    This 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 final rule will not adversely 
directly affect productivity, competition, or prices in the energy 
sector.

I. National Technology Transfer and Advancement Act (NTTAA)

    This rulemaking does not involve technical standards. The rule 
retains requirements for radon monitoring using Method 115 that were 
promulgated in 1989.

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

    The EPA believes that this action does not have disproportionately 
high and adverse human health or environmental effects on minority 
populations, low-income populations and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994). The 
documentation for this decision is contained in Section IV.B.2 of this 
preamble and the Background Information Document prepared to support 
this action (Docket No. EPA-HQ-OAR-2008-0218).

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 61

    Environmental protection, Air pollution control, Hazardous 
substances, Radon, Tailings, Byproduct, Uranium, Reporting and 
recordkeeping requirements.

    Dated: December 20, 2016.
Gina McCarthy,
Administrator.

    For the reasons stated in the preamble, the Environmental 
Protection Agency amends title 40, Chapter I of the Code of Federal 
Regulations as follows:

PART 61--NATIONAL EMISSIONS STANDARDS FOR HAZARDOUS AIR POLLUTANTS

0
1. The authority citation for part 61 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.

Subpart W--National Emission Standards for Radon Emissions From 
Operating Mill Tailings

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2. Section 61.251 is amended by revising paragraphs (b) through (f) and 
adding paragraphs (h) through (o) to read as follows:

Sec.  61.251  Definitions.

* * * * *
    (b) Continuous disposal means a method of uranium byproduct 
material or tailings management and disposal in which uranium byproduct 
material or tailings are dewatered by mechanical methods immediately 
after generation. The dried uranium byproduct material or tailings are 
then placed in trenches or other disposal areas and immediately covered 
to limit emissions consistent with applicable Federal standards.
    (c) Dewatered means to remove the water from recently produced 
uranium byproduct material or tailings by mechanical or evaporative 
methods such that the water content of the uranium byproduct material 
or tailings does not exceed 30 percent by weight.
    (d) Existing conventional impoundment means any conventional 
uranium byproduct material or tailings impoundment which is licensed to 
accept additional uranium byproduct material or tailings and is in 
existence on December 15, 1989.

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    (e) Operation. Operation means that an impoundment is being used 
for the continued placement of uranium byproduct material or tailings 
or is in standby status for such placement. An impoundment is in 
operation from the day that uranium byproduct material or tailings are 
first placed in the impoundment until the day that final closure 
begins.
    (f) Phased disposal means a method of uranium byproduct material or 
tailings management and disposal which uses lined impoundments which 
are filled and then immediately dried and covered to meet all 
applicable Federal standards.
* * * * *
    (h) Conventional impoundment. A conventional impoundment is a 
permanent structure located at any uranium recovery facility which 
contains mostly solid uranium byproduct material or tailings from the 
extraction of uranium from uranium ore. These impoundments are left in 
place at facility closure.
    (i) Non-conventional impoundment. A non-conventional impoundment is 
used for managing liquids from uranium recovery operations and contains 
uranium byproduct material or tailings suspended in and/or covered by 
liquids. These structures are commonly known as holding ponds or 
evaporation ponds and can be located at any uranium recovery facility. 
They are typically not permanent structures unless they transition to 
become used as conventional impoundments. Impoundments constructed for 
the purpose of managing liquids from closure or remediation activities 
(e.g., contaminated groundwater), and which are used solely for that 
purpose, are not subject to the requirements of this subpart.
    (j) Heap leach pile. A heap leach pile is a pile of uranium ore 
placed on an engineered structure and stacked so as to allow uranium to 
be dissolved and removed by leaching liquids.
    (k) Standby. Standby means the period of time that an impoundment 
is not accepting uranium byproduct material or tailings but has not yet 
entered final closure.
    (l) Uranium recovery facility. A uranium recovery facility means a 
facility licensed by the NRC or an NRC Agreement State to manage 
uranium byproduct material or tailings during and following the 
processing of uranium ores. Common names for these facilities are a 
conventional uranium mill, an in-situ leach (or recovery) facility and 
a heap leach facility or pile.
    (m) Heap leach pile operational life. The operational life of a 
heap leach pile means the time period from the first time that 
lixiviant is placed on the heap leach pile until the time the final 
rinse is completed.
    (n) Final closure means the period during which an impoundment or 
heap leach pile is being managed in accordance with the milestones and 
requirements in an approved reclamation plan. Final closure for the 
impoundment or heap leach pile begins when the owner or operator 
provides written notice to the Administrator and to the Nuclear 
Regulatory Commission or applicable NRC Agreement State that:
    (1) A conventional impoundment is no longer receiving uranium 
byproduct material or tailings, is no longer on standby for such 
receipt and is being managed under an approved reclamation plan for 
that impoundment or facility closure plan; or
    (2) A non-conventional impoundment is no longer required for 
evaporation or holding purposes, is no longer on standby for such 
purposes and is being managed under an approved reclamation plan for 
that impoundment or facility closure plan; or
    (3) A heap leach pile has concluded its operational life and is 
being managed under an approved reclamation plan for that pile or 
facility closure plan.
    (o) Reclamation plan means the plan detailing activities and 
milestones to accomplish reclamation of impoundments or piles 
containing uranium byproduct material or tailings. Activities and 
milestones to be addressed include, but are not limited to, dewatering 
and contouring of conventional impoundments and heap leach piles, and 
removal and disposal of non-conventional impoundments. A reclamation 
plan prepared and approved in accordance with 10 CFR part 40, Appendix 
A is considered a reclamation plan in this subpart.

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3. Section 61.252 is revised to read as follows:

Sec.  61.252   Standard.

    (a) Each owner or operator of a conventional impoundment shall 
comply with the following requirements:
    (1) Radon-222 emissions to the ambient air from an existing 
conventional impoundment shall not exceed 20 pCi/(m\2\-sec) (1.9 pCi/
(ft\2\-sec)) of radon-222 and all owners or operators shall comply with 
the provisions of 40 CFR 192.32(a)(1) in the operation of the 
impoundment notwithstanding the exemption for existing impoundments in 
40 CFR 192.32(a)(1).
    (2) After December 15, 1989, no new conventional impoundment may be 
built unless it is designed, constructed and operated to meet one of 
the two following management practices:
    (i) Phased disposal in lined impoundments that are no more than 40 
acres in area and comply with the requirements of 40 CFR 192.32(a)(1). 
The owner or operator shall have no more than two conventional 
impoundments, including existing conventional impoundments, in 
operation at any one time.
    (ii) Continuous disposal such that uranium byproduct material or 
tailings are dewatered and immediately disposed with no more than 10 
acres uncovered at any time and shall comply with the requirements of 
40 CFR 192.32(a)(1).
    (b) Each owner or operator of a non-conventional impoundment shall 
comply with the following requirements: Non-conventional impoundments 
shall meet the requirements of 40 CFR 192.32(a)(1). During operation 
and until final closure begins, the liquid level in the impoundment 
shall be maintained so that solid materials in the impoundment are not 
visible above the liquid surface, verified by daily inspections 
documented through notations and by digital photographic evidence 
collected at least weekly. Should inspection reveal that solid 
materials in the impoundment are visible above the liquid surface, the 
owner or operator must correct the situation within seven days, or 
other such time as specified by the Administrator.
    (c) Each owner or operator of a heap leach pile shall comply with 
the following requirements: Heap leach piles that have completed their 
operating life but have not yet entered final closure shall be managed 
in compliance with the phased disposal management practice in paragraph 
(a)(2)(i) of this section. Heap leach piles shall be constructed in 
lined impoundments that are no more than 40 acres in area and shall 
comply with the requirements of 40 CFR 192.32(a)(1). The owner or 
operator shall have no more than two heap leach piles, including 
existing heap leach piles, subject to this subpart at any one time.

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4. Section 61.255 is revised to read as follows:

Sec.  61.255  Recordkeeping requirements.

    (a) The owner or operator of any uranium recovery facility must 
maintain records that confirm that the conventional impoundment(s), 
non-conventional impoundment(s) and heap leach pile(s) subject to this 
subpart at the facility meet the requirements in 40 CFR 192.32(a)(1). 
These records shall

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include, but not be limited to, the results of liner compatibility 
tests.
    (b) The owner or operator of any uranium recovery facility with 
non-conventional impoundments must maintain written records from daily 
inspections and other records confirming that any sediments have 
remained saturated in the non-conventional impoundments at the 
facility. Periodic digital photographic evidence, with embedded date 
stamp and other identifying metadata, shall be collected no less 
frequently than weekly to demonstrate compliance with the requirements 
of Sec.  61.252(b). Should inspection reveal that a non-conventional 
impoundment is not in compliance with the requirements of Sec.  
61.252(b), the owner or operator shall collect photographic evidence 
before and after the non-compliance is corrected.
    (c) The records required in paragraphs (a) and (b) in this section 
must be kept at the uranium recovery facility for the operational life 
of the facility and must be made available for inspection by the 
Administrator, or his authorized representative.
    (1) Digital photographs taken to demonstrate compliance with the 
requirements of Sec.  61.252(c) shall be submitted electronically using 
the Subpart W Impoundment Photographic Reporting (SWIPR) system that is 
accessed through EPA's Central Data Exchange (CDX) (cdx.epa.gov) at 
least monthly.
    (i) Owners and operators must also submit information identifying 
the facility and facility location, the name or other designation of 
each impoundment, and the date and time of each photograph.
    (ii) If the reporting form specific to this subpart is not 
available in SWIPR, the owner or operator must retain the digital 
photographs at the facility and provide them to the EPA or authorized 
State upon request, with the supporting information required in 
paragraph (c)(1)(i) of this section.
    (2) [Reserved]

[FR Doc. 2016-31425 Filed 1-13-17; 8:45 am]
 BILLING CODE 6560-50-P