Revisions to National Emission
Standards for Operating Uranium
Mill Tailings
United States
Environmental Protection
Agency
Notice of Proposed Rulemaking
Limits on Air Pollution from Uranium
Mill Tailings
EPA limits emissions of hazardous air pollutants under the
authority of the Clean Air Act. EPA's "National Emission
Standards for Hazardous Air Pollutants (NESHAPS)" (40
CFR Part 61) set limits on hazardous air pollutants from
different activities and facilities. Subpart W of 40 CFR Part
61, "National Emission Standards for Operating Uranium
Mill Tailings," limits radon emissions from tailings at
operating uranium mills. EPA originally issued Subpart W
in 1989 (54 FR 51703, December 15, 1989).
Current Standards for Uranium
Mill Tailings
The Subpart W standards limit the radon releases and
doses to the public from the normal operations of facilities
licensed to manage uranium byproduct materials during and
following the processing of uranium ores. The facilities are
commonly known as uranium mills and the byproducts as
tailings. Subpart W currently has different requirements for
byproduct material impoundments built before 1989 and
those built afterward. Pre-1989 impoundments are subject
to a numeric limit on radon emissions. Post-1989 facilities
must control radon limits through one of the two following
work practices:
No more than two impoundments may operate at
any time and each cannot be larger than 40 acres.
Disposal of tailings takes place in phases.
Disposal of tailings takes place continuously, and no
more than 10 acres of tailings may be uncovered at
any time.
The Rulemaking Process: From Laws to
Environmental Standards
An environmental law is enacted when Congress
passes it and the President signs it. Specific laws
make EPA responsible for writing regulations which
specify what must be done to obey the law. Many
environmental regulations set standards that limit the
amount of a hazardous material that can be discharged
into the environment.
After an environmental law is enacted, EPA conducts
a scientific analysis of the issues and, if necessary,
proposes new or revised regulations in a Notice of
Proposed Rulemaking (NPRM). The proposal is listed
in the Federal Register so that members of the public
can consider it and send their comments to us. EPA
will consider the comments received as it finalizes the
regulations. The comments and EPA's response to them
become part of the public record.
Final regulations are published in the Federal Register
as a Final Rule, and added to the Code of Federal
Regulations (CFR).
How You Can Participate
The public will have 90 days to submit comments on
this Notice of Proposed Rulemaking starting the day of
its publication in the Federal Register. All submissions
will become part of the official public record for this
rulemaking. Be sure to identify your submission by
Docket ID No. EPA-HQ-OAR-2008-0218. You can
submit comments by email, by regular mail, online
or in person. Detailed instructions for submission of
comments are in the Notice of Proposed Rulemaking
(NPRM). A link to the text is provided at:
www.epa.gov/radiation
United States Environmental Protection Agency | Office of Radiation and Indoor Air (6608J)
EPA 402-F-13-052 | April 2014
www.epa.gov/radiation
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Why Revise the Standards?
The Clean Air Act Amendments of 1990 require EPA
to review the standards of Subpart W periodically. After
completing a recent review, EPA concluded that revisions
were needed to clarify definitions and to be more specific
about what kind of tailings impoundments are subject to the
standard. EPA also concluded that requirements for generally
available control technology (GACT) or management
practices are the best means to control radon emissions from
tailings piles. GACT are commercially available methods,
practices and techniques for operation and maintenance of
emissions control systems.
Key Changes in the Proposed Rule
Definition of Uranium Recovery Facilities: The proposed
rule would apply to all operating uranium recovery facilities,
which are defined as those facilities that manage uranium
byproduct material or tailings, including conventional
uranium mills, in-situ leach recovery facilities, and heap
leach facilities. "Operating" means that an impoundment
is being used for the continued placement of uranium
byproduct material or tailings, or is in standby status.
GACT for All Conventional Impoundments, Regardless
of Age: In the proposed rule, EPA would no longer have
different standards for impoundments constructed before
and after 1989. EPA is proposing that the work practices
for impoundments built after 1989 would be required as
GACT at all conventional impoundments, regardless of their
age. Studies of the work practices have shown that they are
effective in controlling radon releases to the environment.
EPA proposes dropping the numeric radon standard for
pre-1989 facilities because it is not needed when the GACT
controls are in place.
GACT for Non-Conventional Impoundments: "Non-
conventional" impoundments (commonly known as
evaporation or holding ponds) hold uranium byproduct
materials in ponds that are covered by liquids. In this
proposed rule, EPA would require control of radon emissions
by covering the tailings in the ponds with at least one meter
of liquid at all times.
GACT for Heap Leach Piles: EPA is proposing to require
operating heap leach piles to maintain a moisture content of
30 percent at all times. Studies have shown that 30 percent
moisture content keeps radon emissions from heap piles at
acceptable levels.
Construction Requirements for All Impoundments:
The current Subpart W standard references other regulations
that require impoundments to be designed, constructed and
installed in a way that protects adjacent soils and waters.
Specifications include top and bottom liners as well as a
leachate collection and removal system. In the proposed
rule, these requirements would apply to all types of uranium
recovery facilities.
Recordkeeping Requirements: Under the proposed
rule, uranium recovery facilities would have to maintain
records to demonstrate compliance with requirements for
impoundment construction, liquid coverage of ponds, and
moisture content of heap leach piles.
EPA and Uranium Extraction Operations
EPA's mission is to protect human health and the
environment. The Agency sets limits on the amount of
radioactivity that can be released into the environment. EPA
enforces the Clean Air Act requirements at Subpart W. The
Nuclear Regulatory Commission (NRC) has regulatory
responsibility for licensing and operation of uranium
extraction facilities and other commercial facilities that use
radioactive materials.
If enacted, this proposed rule would not relieve the owner or
operator of the uranium recovery facility of the monitoring
and maintenance requirements of their operating license
issued by the NRC or its Agreement States.
Other Regulatory Agencies
U.S. Nuclear Regulatory Commission (NRC): The
NRC regulates the civilian uses of nuclear materials
in the United States by licensing facilities that
possess, use or dispose of nuclear materials;
establishing standards; and inspecting licensed
facilities.
States: Most states have agencies responsible
for regulating the use of radiation and radioactive
emissions. Some states operate under agreement
with the NRC to license and regulate certain types of
radioactive materials.
United States Environmental Protection Agency | Office of Radiation and Indoor Air (6608J)
EPA 402-F-13-052 | April 2014
www.epa.gov/radiation
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