EPA's Final Health and Safety Standard for Yucca Mountain

EPA’s Final Health and Safety Standard
for Yucca Mountain
October 6, 2008
Bonnie C. Gitlin
Section Research Manager
Resources, Science, and Industry Division

EPA’s Final Health and Safety Standard
for Yucca Mountain
On September 30, 2008, the Environmental Protection Agency (EPA) issued
the long-awaited revision to its 2001 Public Health and Safety Standard for the
proposed Yucca Mountain deep geologic repository for high-level radioactive waste
and spent nuclear fuel. While the issuance of the standard allows the Nuclear
Regulatory Commission (NRC) to issue its final conforming standards and move
forward toward a final license decision for the facility, EPA’s standard raises several
unprecedented regulatory issues and is likely to be further challenged in court. EPA’s
final regulation represents the first time the federal government has attempted to
regulate public health far into the future, for a period of up to 1 million years. The
continued prospect of legal challenges creates an uncertain atmosphere around the
licensing process. It has been argued that the government’s difficulty promulgating
a legally defensible public health and safety standard for the Yucca Mountain
repository has far-reaching impacts on the nuclear industry and the viability of
nuclear power as a long-term component of the United States’ energy strategy.
Permanent disposition of spent nuclear fuel and high-level radioactive waste has
been the subject of substantial controversy for several decades. The creation of a deep
geologic repository for this type of waste has been an element of U.S. nuclear policy
since the early 1980s. The technical, legal, and policy challenges have delayed
development of a repository and created an uncertain environment for high-level
nuclear waste management in the United States.
Congress has held several hearings in the past few years focusing on the
administration’s progress toward finalizing the health and safety standard, the
technical soundness of the Department of Energy’s (DOE’s) design for the facility,
the relationship of the project to broader energy policy, and transportation safety
issues for waste packages eventually sent to the facility, among other issues. Funding
for the program has also been controversial.

Background ..................................................1
The Court Ruling..............................................2
2005 Proposed Final Rule.......................................3
2008 Final Rule...............................................3
What Standard Has EPA Chosen?.............................3
What Is the Basis for EPA’s 2008 Standard?....................4
Key Questions................................................4
Protecting Public Health....................................5
Legal Uncertainty..........................................6
Meeting the Standard.......................................6
Conclusion ...................................................7

EPA’s Final Health and Safety Standard
for Yucca Mountain
The Nuclear Waste Policy Act of 1982 (NWPA, P.L. 97-425) defined the basic
roles of the three federal agencies with responsibility over the selection, licensing,
and health and safety of the first U.S. high-level radioactive waste disposal site. The
Environmental Protection Agency’s (EPA’s) role is to establish the public health and
safety standards for high-level waste disposal; the Nuclear Regulatory Commission
(NRC) licenses and regulates the repository, using EPA’s standards as the
compliance measure; the Department of Energy (DOE) constructs and operates the
repository. The Energy Policy Act (EPAct) of 1992 (P.L. 102-486) maintained these
roles, but established new requirements specific to the Yucca Mountain, Nevada site.
EPA was directed to issue new environmental standards specifically for the Yucca
Mountain repository site. General EPA repository standards previously issued and
subsequently revised no longer could be applied to Yucca Mountain. DOE and NRC
had raised concerns that some of EPA’s general standards might have been1
impossible or impractical to meet at Yucca Mountain.
EPAct also required EPA to contract with the National Academy of Sciences
(NAS) for a technical study of “reasonable” standards that might apply to the Yucca
Mountain site, and required that any standard set by EPA be “based upon and
consistent with” the National Academy’s findings and recommendations. The2
resulting study was issued August 1, 1995. The NAS study recommended that the
Yucca Mountain environmental standards establish a limit on risk to individuals near
the repository, rather than setting specific limits for the releases of radioactive
material or on radioactive doses, as under previous EPA standards. The NAS study
also examined the potential for human intrusion into the repository and found no
scientific basis for predicting human behavior thousands of years into the future.
On June 13, 2001, EPA issued a final Health and Safety Standard for the Yucca3
Mountain High-Level Radioactive Waste Repository. The regulation established a

1 For more information see CRS Report RL33461, Civilian Nuclear Waste Disposal, by
Mark Holt.
2 The final standard is currently only available on EPA’s website, pending publication in the
Federal Register. [http://www.epa.gov/yucca].
3 40 CFR 197 Public Health and Environmental Radiation Protection Standards for Yucca
Mountain Nevada, June 13, 2001.

15 millirem/year (mrem/yr)4 exposure standard for the facility that applied for 10,000
years based on projected doses to a Reasonably Maximally Exposed Individual
(RMEI) from the undisturbed repository as well as circumstances of human intrusion.
The rule established a separate groundwater protection standard equivalent to today’s
drinking water standards also applicable for 10,000 years. EPA’s rule also required
DOE to continue RMEI projections beyond 10,000 years to the time of peak dose, but
declined to set numerical standards beyond the 10,000-year time frame.
EPA calculated that its standard would result in an annual risk of fatal cancer
for the RMEI of seven chances in a million. The nuclear industry criticized the EPA
proposal as being unnecessarily stringent, particularly the groundwater standard. On
the other hand, environmental groups contended that the 10,000-year standard
proposed by EPA was too short, because DOE had projected that radioactive releases
from the repository would peak after about 400,000 years. Despite DOE’s opposition
to the EPA standards, the Department’s site suitability evaluation determined that the
Yucca Mountain site would be able to meet them. NRC revised its repository
regulations on September 7, 2001, to conform to the EPA standards.
The Court Ruling
Various aspects of the 2001 regulation were challenged in lawsuits filed with
the U.S. Court of Appeals for the District of Columbia in July 2001. The State of
Nevada, the Natural Resources Defense Council (NRDC), and the Nuclear Energy
Institute (NEI) each challenged different aspects of the rule. Nevada and the NRDC
challenged the rule on the grounds that it was not sufficiently protective and had not
been adequately justified, focusing on the 10,000-year time period. NEI challenged
the groundwater protections as unnecessary, contrary to recommendations of the
NAS, and outside the agency’s authority under the EPAct.
On July 9, 2004, the U.S. Circuit Court of Appeals for the District of Columbia
dismissed the NEI groundwater challenge, and all but one of the challenges by
Nevada and NRDC. On the issue of the 10,000-year compliance standard, the Court
upheld the challenge and vacated the 2001 standard, ruling that the 10,000-year
compliance time frame was not “based upon and consistent with” the NAS finding
that “there is no scientific basis for limiting the time period to 10,000 years or any
other value ...” and their recommendation “that compliance assessment be conducted
for the time when the greatest risk occurs within the limits imposed by long-term
stability of the geologic environment.”5

4 Radiation exposure standards typically do not specify the amount of radioactivity that can
be released into the environment. Rather, these standards specify the maximum allowable
exposure of an individual to radiation over a certain period of time, based on health risks
that regulators determine as acceptable. In U.S. regulations, the amount of allowable
exposure typically is measured in rems and millirems of radiation, accumulated over a one
year period or millirems/year. (One rem is equivalent to 1,000 millirems.)
5 Nuclear Energy Institute v. Environmental Protection Agency, U.S. Court of Appeals for
the District of Columbia Circuit, No. 01-1258, July 9, 2004.

2005 Proposed Final Rule
In response to the court decision, EPA proposed a new version of the Yucca
Mountain standard on August 22, 2005. The proposal retained the dose limits of the
2001 standard for the first 10,000 years but proposed a higher annual dose of 350
mrem/yr for the period of 10,000 years through 1 million years. EPA based the
standard on variations in natural background radiation between Colorado and
Amargosa Valley, Nevada, arguing that it was reasonable to use natural background
as a benchmark for exposure when the compliance point was up to 1 million years
in the future. The agency also argued that it was reasonable to consider protective
exposures no greater than residents of Colorado experience today from natural
background radiation alone.6 EPA also proposed basing the post-10,000-year
standard on the median dose, rather than the mean, an approach that some argued
would make it easier for DOE to meet the standard. Nevada state officials called
EPA’s proposed standard far too lenient and charged that it was “unlawful and
arbitrary.”7 Comments submitted to the public docket both praised and attacked
EPA’s proposal. Those in favor of the proposal focused on the unprecedented time
frames and the reasonableness of drawing comparisons with natural levels of
radioactivity; opponents claimed that the proposal violated EPA’s basic principles
of public health protection and was designed specifically to allow the facility to be
2008 Final Rule
What Standard Has EPA Chosen? In its final standard,8 EPA has
established a dual compliance standard: 15 mrem/yr with a separate groundwater
protection standard for the first 10,000 years, and 100 mrem/yr for the period from
10,000 up to 1 million years. The concept of a dual standard was introduced in
EPA’s August 2005 proposal and has remained controversial. EPA maintains that
the dual approach provides a reasonable measure of the disposal system’s
performance that appropriately combines protectiveness with recognition of the
limitations of modeling in predicting the evolution of the system over hundreds of
thousands of years. Critics argue that the dual standard explicitly condones a lesser
level of protection for future generations and is designed to make it easier for the
Department of Energy to ultimately meet the standard.
EPA also specified that the mean of the distribution of results should be used
to demonstrate compliance with the standard at all times. This is a departure from
the proposal, in which EPA specified the mean during the pre-10,000-year period, but
chose the median for the post-10,000-year period. At the time, EPA stated its belief
that the median better represented the central tendency of the likely distribution of
results in DOE’s performance assessment. In the final rule, EPA returned to the

6 In the proposed rule (Federal Register Vol. 70 No. 161 40 CFR Part 197 p 49037) EPA
estimated the natural background exposure in Colorado to be about 700 mrem/yr.
7 See CRS Report RL33461, Civilian Nuclear Waste Disposal, by Mark Holt.
8 [http://www.epa.gov/rpdweb00/docs/yucca/RIN%202060-an15-final-40-cfr-197amend

mean for both time periods, citing public comments that pointed to a
recommendation in the NAS report that the mean be used as the basis for any
standard. 9
What Is the Basis for EPA’s 2008 Standard? In choosing 100 mrem/yr
as the final standard for the 10,000 to 1 million-year time period, EPA abandoned the
controversial “variations in natural background” approach it proposed in 2005. That
approach would have set the standard based on comparisons of background levels
between Amargosa Valley (the closest populated area to the proposed facility) and
another geographical location in the United States. For the proposal, EPA chose
Colorado. Their concept was that, so long as the hypothetical future residents of
Amargosa Valley did not receive more radiation exposure in the far future than
residents of Colorado receive from natural background radiation today, the exposure
could be considered protective. EPA cited the unprecedented time period as one
justification for its approach and referenced international precedent for using natural
background levels as a “reasonable and logical reference point.”10
In the final standard, EPA changed its approach. EPA states that it was not
possible to reliably estimate levels of background exposure in a way that was relevant
to making the kinds of comparisons between locations it envisioned in the proposal.
EPA concluded that “comparing background radiation estimates from specific
locations does not provide a clear or sufficient basis for a regulatory standard11
applicable to the Yucca Mountain disposal system.” The agency did not abandon
comparisons to background completely. The final rule notes that the 100 mrem/yr
level “reasonably comports” with background estimates in Amargosa Valley, but
relies more heavily on arguments that 100 mrem/yr is directly protective of public
health. EPA cites both national and international standards in support of its decision,
and points to existing domestic regulations,12 which each use 100 mrem/yr, as well
as the National Council on Radiological Protection (NCRP) endorsement of the 100
mrem/yr level incorporated in the international system of radiation protection.13 EPA
went on to state that it “acknowledges and concurs with the broad consensus in the
protectiveness of the 100 mrem/yr level and, furthermore, considers it especially
suitable for application to the extreme far future, when planning for and protecting
public exposures is much less certain.”
Key Questions
Comments submitted to the public docket both praised and attacked EPA’s 2005
proposal. Those in favor of the proposal emphasized the unprecedented time frame

9 National Research Council. Technical Bases for Yucca Mountain Standards. National
Academy Press. 1995. p. 123.
10 Federal Register Vol. 70 No. 161, 40 CFR Part 197, p. 49039.
11 EPA final rule, p. 71 [http://www.epa.gov/rpdweb00/docs/yucca/RIN%202060-an15-
12 NRC’s 10 CFR20.1301 and DOE Order 5400.5.
13 National Council for Radiation Protection Report 116, Limitation of Exposure to Ionizing

and the reasonableness of drawing comparisons with natural levels of radioactivity
at such long time frames. Supporters of the repository see EPA’s regulation as the
last tool NRC needs to complete its technical review. Opponents raised issues with
the 2005 proposal in three key areas: 1) they claimed that the proposal was not
protective of public health, 2) that it was legally indefensible; and 3) it was designed
specifically to allow the facility to be built. Nevada state officials called EPA’s
proposed standard far too lenient and charged that it was “unlawful and arbitrary.”14
In the final regulation, EPA argues that it has addressed these issues; it lowered
the numerical standard significantly, from the 350 mrem/yr in the proposal to 100
mrem/yr, explaining that the original assumptions it used to justify comparing
background levels in geographically similar areas were called into question by new
data submitted during the public comment period. Acknowledging that it was unable
to arrive at defensible estimates of natural background,15 EPA opted to use a different
approach for the final standard. Some may argue that even adopting the 100 mrem/yr
level as EPA did in the final standard is not protective of public health and that the
final standard is further flawed by promulgating a dual standard that adopts a lesser
level of protection for future generations than applies for the first 10,000 years.
Protecting Public Health. There has been much debate over the years about
what is protective of public health when it comes to radiation. EPA has repeatedly
held that an increased risk over a lifetime of 1 in 10,000 to 1 in 1 million excess
cancer deaths is protective. The original 2001 Yucca Mountain regulation adopted
a 15 mrem/yr standard for 10,000 years, which, at the time, the agency calculated was16
equivalent to a 7 to 8.5 in 1 million annual cancer risk. The final 2008 regulation
maintains this level for the first 10,000 years. In considering the unprecedented
challenge of carrying the compliance standard beyond 10,000 years out to 1 million
years, EPA argues that a different framework should apply. EPA estimates that the-5
nominal annual risk associated with 100 mrem/yr is 5.75 x 10 or 5.75 in 100,000,
which the it describes as fully consistent with the NAS report. EPA considers the
standard both protective, given the extremely long time frames involved, and
reasonable because it effectively addresses the uncertainty in projecting doses for up
to a million years. The agency also emphasizes what it considers a “broad consensus”
regarding 100 mrem/yr as a protective public dose limit. Some disagree with this-3
assessment, arguing that a 100 mrem/yr exposure results in a 4 x 10 or 4 in 1,000
risk over a 70-year lifetime,17 a level of risk that would be unacceptable in a18
regulation today.

14 See CRS Report RL33461, Civilian Nuclear Waste Disposal, by Mark Holt.
15 [http://www.epa.gov/rpdweb00/docs/yucca/RIN%202060-an15-final-40-cfr-197amend
16 40 CFR 197.
17 EPA Response to Comments, p. 168 [http://www.epa.gov/rpdweb00/docs/yucca].
18 There has been ongoing disagreement among federal regulatory agencies as to what
exposure limit is adequate to protect human health, resulting in standards of varying
stringency. Accordingly, federal radiation exposure standards vary depending on the source
and conditions. For example, worker protection standards are the least stringent, allowing

In the 2008 regulation, EPA argues that the increasing uncertainty in dose
projections over very long time periods reduces the ability of performance assessment
modeling to meaningfully distinguish among alternative and equally likely “futures”
represented by individual model simulations. EPA also explained that it was
attempting to balance the principles of intergenerational equity with the need to
create a compliance standard that did not demand more than can be provided by
scientific analysis. EPA argues that the dual nature of the regulation acheives this
Legal Uncertainty. Critics believe EPA’s standard will be legally vulnerable
because they maintain that it does not fully address the District Court’s direction to
be based upon and consistent with the NAS report. They have also argued that any
standard that accepts a greater individual risk in the far future than what we would
consent to today is both not protective and not consistent with the NAS
recommendation. There are many opinions on which parts of the standard may be
vulnerable to legal challenge, and many more opinions about whether the regulation
would survive challenge. Some Senate leaders have predicted further litigation,
arguing that the standard is weak and puts people unnecessarily at risk.19
Meeting the Standard. There are several aspects to consider related to the
potential for any facility to establish compliance with a regulatory standard when
likely exposures occur so far in the future. First, can DOE adequately demonstrate,
using probabalistic models, that the design of the facility is sufficient to meet EPA’s
and NRC’s regulatory standards? Modeling the performance of an engineering
design is not unusual. What makes the Yucca Mountain repository, or any other deep
geologic repository, unusual is the time span over which the model must be extended.
Many assumptions must be built into the model to account for both natural and man-
made variables, all of which carry their own uncertainties. These uncertainties are
magnified when the projection is extended over tens of thousands, or in this case,
over 1 million years. In its revised Final Supplementary Environmental Impact
Statement for the Yucca Mountain repository, DOE estimates the maximum mean
annual individual dose at 2 mrem/yr,20 a level that appears to meet EPA’s 100
mrem/yr standard. DOE, however, has cautioned that, should the assumptions it used
to develop the probabilistic model be successfully challenged during NRC’s licensing
process, their estimates of maximum annual individual dose could change. A DOE
spokesperson has stated that DOE believes it can meet EPA’s standard,21 but many
critics, including the state of Nevada, are skeptical that any facility will be able to

18 (...continued)
individual exposure of up to 5 rems (5,000 millirems) per year, whereas the most stringent
standard is EPA’s drinking water standard of 4 millirems per year. The substantially greater
stringency of the drinking water standard is attributed to the potential for internal human
exposure through consumption.
19 [http://reid.senate.gov/newsroom].
20 [http://www.ocrwm.doe.gov/ym_repository/seis/docs/002_Summary.pdf].
21 Allen Bensen, DOE spokesperson, quoted in the Las Vegas Review Journal, October 1,

2008, [http://www.lvrj.com/news/29991329.html].

demonstrate through engineering design and probabilistic modeling that it can protect
the public from exposure for 1 million years.
Now that EPA has issued the final health and safety standard, attention will shift
to the licensing process and the many technical and policy issues to be addressed in
that context. NRC’s technical review and licensing process will take several years
and may proceed regardless of additional legal challenges to EPA’s standard. As
Congress continues to oversee the Yucca Mountain repository program, it will face
issues related to whether DOE’s technical work is sufficient to demonstrate
compliance with EPA’s standard and other safety issues surrounding storage and
transportation of spent nuclear fuel and high level radioactive waste to the facility
should it be licensed. Annual appropriations will be a key venue in this debate. Some
have argued that it would be a better public policy choice to continue to store nuclear
waste on-site at the power plants where it is produced while continuing to search for
as a safer, more cost-effective solution to permanent disposal of spent nuclear fuel
and high-level nuclear waste. A larger issue is how will the continuing controversy
over the Yucca Mountain Project affect the U.S. nuclear power industry and its role
in broader national energy policy.