[Federal Register Volume 73, Number 144 (Friday, July 25, 2008)]
[Proposed Rules]
[Pages 43381-43385]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-17108]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 20
[Docket No. PRM-20-26; NRC-2005-0017]
James Salsman; Denial of Petition for Rulemaking
AGENCY: Nuclear Regulatory Commission.
ACTION: Denial of petition for rulemaking.
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SUMMARY: The Nuclear Regulatory Commission (NRC) is denying a petition
for rulemaking (PRM-20-26) submitted by James Salsman (petitioner). The
petitioner requested that NRC amend its regulations to modify exposure
and environmental limits for heavy metal radionuclides, in particular
uranium. NRC is denying the petition because current NRC regulations
provide adequate protection of public health and safety. The petitioner
has not presented sufficient peer-reviewed data, pertinent to the types
and levels of exposures associated with the concentration values used
in NRC's regulations, to provide a sufficient reason for NRC to
initiate a revision of its regulations. Thus, the NRC has decided not
to expend limited resources on initiating a rulemaking at this time.
ADDRESSES: You can access publicly available documents related to this
petition for rulemaking using the following methods:
Federal e-Rulemaking Portal: Go to http://www.regulations.gov and
search for documents filed under Docket ID [NRC-2008-0017].
NRC's Public Document Room (PDR): The public may examine and have
copied for a fee publicly available documents at the NRC's PDR, Public
File Area O1 F21, One White Flint North, 11555 Rockville Pike,
Rockville, Maryland.
NRC's Agencywide Documents Access and Management System (ADAMS):
Publicly available documents created or received at the NRC are
available electronically at the NRC's electronic Reading Room at http://www.nrc.gov/reading-rm/adams.html. From this page, the public can gain
entry into ADAMS, which provides text and image files of NRC's public
documents. If you do not have access to ADAMS or if there are problems
in accessing the documents located in ADAMS, contact the NRC PDR
reference staff at 1-899-397-4209, 301-415-4737, or by e-mail to
[email protected].
FOR FURTHER INFORMATION CONTACT: Frank Cardile, Office of Federal and
State Materials and Environmental Management Programs, U.S. Nuclear
Regulatory Commission, Washington, DC 20555-0001, telephone (301) 415-
6185, e-mail [email protected].
SUPPLEMENTARY INFORMATION:
I. The Petition
On June 15, 2005 (70 FR 34699), NRC published a notice of receipt
of a petition for rulemaking filed by James Salsman. The petitioner
requested that NRC revise its regulations in 10 CFR part 20 that
specify limits for ingestion and inhalation occupational values,
effluent concentrations, and releases to sewers, for heavy metal
radionuclides, with nonradiological chemical toxicity hazards exceeding
that of their radiological hazards so that those limits properly
reflect the hazards associated with danger to organs, reproductive
toxicity, and all other known nonradiological aspects of heavy metal
toxicity. Specifically, the petition focused on uranium toxicity. The
petitioner also requested that the classification for uranium trioxide
within Class W, given in the Class column of the table for Uranium-230
in Appendix B to 10 CFR part 20, be amended to Class D. In addition,
the petitioner requested that monomeric (monomolecular) uranium
trioxide gas, as produced by the oxidation of
U3O8 at temperatures above 1000[deg] Celsius, be
assigned its own unique solubility class if necessary, when its
solubility characteristics become known.
In providing support for the petition, the petitioner states that
NRC's regulations were designed to address only the radiological hazard
of uranium, and not heavy metal toxicity which is known to be about six
orders of magnitude worse. The petitioner believes that current
regulations allow intake of more soluble compounds than insoluble
compounds and that, in practice, the soluble compounds are more toxic
than the insoluble compounds. The petitioner states that this should
indicate that long half-life uranium isotope standards need to be
revised.
The petitioner states that the current NRC regulations allow an
annual inhalation of more than two grams of uranium. The petitioner
also states that because ``...the LD50/30 [lethal dose to 50 percent of
a population in 30 days] of uranyl nitrate (which has considerably less
uranyl ion per unit of mass than uranium trioxide) is 2.1 mg/kg in
rabbits, 12.6 mg/kg in dogs, 48 mg/kg in rats, and 51 mg/kg in guinea
pigs and albino mice,'' two grams of UO3 seems very likely
to comprise a fatal dose for a 200 pound human (Gmelin
[[Page 43382]]
Handbook of Inorganic Chemistry, 8th edition, English translation
(1982), Vol. U-A7, pp. 312-322). The petitioner indicates that
the values in NRC's regulations seem much too high and were likely
derived to avoid immediate kidney failure, without regard to
reproductive toxicity nor with sufficient care to avoid allowing lethal
exposures. The petitioner states that the limit of 10 mg/day \1\ of
soluble uranium compounds (or about half a gram per year) in 10 CFR
20.1201(e) seems likely to allow substantial kidney damage and certain
reproductive toxicity. The petitioner states that the correct way to
account for the reproductive toxicity is probably to measure resulting
mutations of mammalian peripheral lymphocytes.
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\1\ 10 CFR 20.1201(e) limits soluble uranium intake to 10 mg/
week, not 10 mg/day as asserted by the petitioner.
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In support of the petitioner's request for changes to solubility
classes, the petitioner states that the primary mode of uranium
toxicity involves much greater solubility. The petitioner asserts that
UO3 should be amended from Class W to Class D based on
Morrow, et al., Health Physics, 1972 ``Inhalation Studies of Uranium
Trioxide'' (Health Physics, vol. 23 (1972), pp. 273-280), which states:
``inhalation studies with uranium trioxide (UO3) indicated
that the material was more similar to soluble uranyl salts than to the
so-called insoluble oxides UO3 is rapidly removed from the
lungs, with most following a 4.7 day biological half time.'' The
petitioner also states that monomeric uranium trioxide gas will turn
out to be absorbed more rapidly in the mammalian lung than uranyl
nitrate, because of its monomolecular gas nature, and not merely about
as rapidly as the studies of granular uranium trioxide by P.E. Morrow,
et al., indicate (``Inhalation Studies of Uranium Trioxide,'' Health
Physics, vol. 23 (1972), pp. 273-280). The petitioner states that even
Class D may not be appropriate for monomolecular uranium trioxide gas
and that it should be assigned its own unique solubility class, if
necessary, when its solubility characteristics become known (R. J.
Ackermann, R. J. Thorn, C. Alexander, and M. Tetenbaum, in ``Free
Energies of Formation of Gaseous Uranium, Molybdenum, and Tungsten
Trioxides,'' Journal of Physical Chemistry, vol. 64 (1960) pp. 350-355:
``gaseous monomeric uranium trioxide is the principal species produced
by the reaction of U3O8 with oxygen'' at
1200[deg] Kelvin and above).
In providing additional technical support of the petition, the
petitioner referenced several studies regarding potential uranium
toxicity, including follow-up studies of health impacts on Gulf War
veterans of exposure to depleted uranium (DU) (see Section III(4) of
this document). In addition to these references submitted as part of
the petition, the petitioner also referenced several studies in three
e-mails submitted in support of the petition as part of the public
comment process. These documents, discussed in Section II of this
document, were also considered as part of NRC's response to the
petition in Section III(4) of this document. In addition, on April 3,
2005, the petitioner filed a separate petition (ML051240497) under 10
CFR 2.206 of the Commission's regulations regarding impacts of
operation of DU munitions licensees on the public health and safety. As
part of that proceeding, the petitioner submitted several additional
documents related to potential impacts of uranium chemical toxicology
on public health and safety and uranium chemical behavior in various
environments. These studies were also considered as part of NRC's
response to the petition in Section III(4) of this document. All of the
supporting studies referenced by the petitioner focused on the toxicity
of uranium; similar studies were not submitted regarding other heavy
metals.
II. Public Comments on the Petition
The notice of receipt of the petition for rulemaking invited
interested persons to submit comments. The comment period closed on
August 29, 2005. NRC received eight comment letters before the comment
period closed and four additional comments after the close of the
comment period. There were four letters from the general public
supporting the petition, including three from the petitioner. There
were eight letters opposing the petition, including five from the
uranium industry, one from the Nuclear Energy Institute (NEI), one from
a physician, and one from an individual.
Commenters supporting the petition noted that the U.S. Code, Title
42, Section 2114, states that NRC is to protect public health and
safety from non-radiological as well as radiological hazards.\2\ These
commenters state that current regulations are inadequate because they
ignore reproductive toxicity of heavy metals and that toxins should not
be released if a fully established toxicology profile is not prepared.
These commenters cite information indicating that the chemical toxicity
of uranium is 6 orders of magnitude greater than its radiological
toxicity in vitro and that the toxicity profile for uranium combustion
product inhalation in humans is unknown beyond 14 years and that
uranium accumulates in testes damaging sperm cells and induces
chromosome damage. These commenters referenced studies that
specifically considered potential uranium reproductive toxicity on Gulf
War Veterans and also referenced additional studies which cited
potential chemical neurotoxicity of uranium based on studies of effects
of brain function in rats following intake of uranium (see Section
III(4) of this document). In referring to a U.S. Transuranium and
Uranium Registries (USTUR) study cited by the uranium industry, these
commenters stated that a relative amount of uranium in a human body in
the USTUR study has no bearing on the question of reproductive
toxicity. Instead, these commenters assert that only the extent to
which the uranium may cause chromosome damage is important, and that
regulators should establish uranium exposure limits to avoid
unacceptable levels of reproductive harm. These commenters state that
despite the amount of data being small and/or the level of harm not
known, the Commission must protect public health and safety by setting
acceptable exposure limits even if that requires extrapolating the
existing known toxicity profile of heavy metal and assuming worst cases
and/or performing additional research on uranium exposure.
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\2\ U.S. Code, Title 42, Section 2114 applies to a specific
category of byproduct material defined in section 11(e)(2) of the
Atomic Energy Act of 1954, as amended. Section 11(e)(2) byproduct
material includes ``the tailings or wastes produced by the
extraction or concentration of uranium or thorium from any ore
processed primarily for its source material content.''
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Those commenters who opposed the petition noted that non-
radiological effects are better, and adequately, addressed elsewhere in
Federal regulations and that NRC's current regulations address both
radiological and chemical toxicity of uranium. In addition, these
commenters note that NRC recognizes that the chemical toxicity of
uranium is greater than radiological toxicity in 10 CFR 20.1201 and
that the current limits set forth in 10 CFR part 20 are protective of
human health. With regard to chemical toxicity, these commenters cited
a National Institute of Occupational Safety and Health study on uranium
mill workers that states that mortality was less than expected and
lower than the general population, and that there is no statistically
significant increase in deaths due to renal failure. These
[[Page 43383]]
commenters note that this suggests that current low exposure standards
have a considerable margin of safety with respect to chemical toxicity.
These commenters also stated that workers engaged in handling uranium
have experienced very few, if any, adverse health impacts. These
commenters also provided comment on studies cited by the petitioner on
reproductive toxicity and neurotoxicity (see Section III(4) of this
document). These commenters cited a USTUR study which stated that
levels in testes of a man exposed to uranium during a working career
are not uncommon among that seen in the aged, indicating that uranium
in reproductive organs is not a major issue. These commenters note that
some data cited in the petition may not adequately represent American
workers, are not rigorously documented, or were at doses in excess of
uranium exposure limits. Thus, overall, these commenters note that,
until data from rigorous toxicological studies are available, there is
inadequate data on uranium toxicity at current permissible exposure
levels to warrant changes to 10 CFR part 20.
III. Reasons for Denial
NRC is denying this petition. The rationale for NRC's denial of the
petition is discussed as follows.
(1) NRC's Current Regulations Limiting Occupational Exposure
Provide Adequate Protection of Public Health and Safety.
NRC has established standards for protection against ionizing
radiation resulting from activities conducted by licensees and has
codified these standards in 10 CFR Part 20. These regulations are
intended to control the receipt, possession, use, transfer, and
disposal of licensed material by its licensees. Licensed material is
any source, byproduct, or special nuclear material received, possessed,
used, transferred, or disposed of under a general or specific license
issued by NRC.
Appendix B, Table 1, to 10 CFR part 20 lists ``Annual Limits on
Intake'' (ALI) and ``Derived Air Concentrations'' (DAC) of
radionuclides for occupational exposure. In addition to these
radiological values, NRC's regulations in 10 CFR part 20 also contain
the following specific limits for uranium based on chemical toxicity:
Sec. 20.1201(e) requires licensees to limit soluble uranium intake by
an occupationally-exposed individual to 10 mgU/week; and Appendix B to
10 CFR part 20, Footnote 3, limits occupational exposure to mixtures of
soluble uranium to an average of 2 mgU/m\3\ over a 40 hour period.
These uranium limits are based on chemical toxicity and are limiting in
situations where the ALI and DAC would allow intake of greater than 10
mgU/week, or exposure to greater than 2 mgU/m\3\ averaged over a 40
hour period.
The basis for NRC's occupational chemical toxicity limits for
uranium are given in an amendment to 10 CFR part 20 (39 FR 13671; April
16, 1974) and are based on the threshold limit value (TLV) of 0.2 mgU/
m\3\ as adopted by the American Conference of Governmental Industrial
Hygienists (ACGIH). Federal Guidance Report (FGR) No. 11, which was
published by the Environmental Protection Agency's (EPA) Office of
Radiation Programs, states that recommendations of the ACGIH should be
consulted when limiting the airborne concentration of chemical
substances in the workplace.\3\ The ACGIH is an independent scientific
organization made up of industrial hygienists and other occupational
health and safety professionals and whose committees review existing
published and peer-reviewed literature in various scientific
disciplines (e.g., industrial hygiene, toxicology, occupational
medicine, and epidemiology). Based on these reviews, the ACGIH
publishes guidelines known as TLVs for making decisions regarding safe
levels of exposure to various chemical agents found in the workplace.
Recommendations of the ACGIH consider health impairments that shorten
life expectancy, compromise physiological function, impair ability to
resist other toxic substances, or adversely affect reproductive
function, and are reviewed and updated periodically. ACGIH notes that
each year it publishes TLVs, provides public notice of its TLVs,
invites interested parties to submit substantive data and comments to
assist in its deliberations, and places certain chemicals on its
``Under Study'' list. This information and data is then collected and
reviewed by an ACGIH committee and ratified, as appropriate, for
inclusion in ACGIH updates on TLVs. Despite the continuing review
undertaken during this process, the uranium TLV of 0.2 mgU/m\3\ has not
been changed by ACGIH in 30 years nor, as of May 2008, is the uranium
TLV listed on the ACGIH's Under Study list on its Web site. Based on
the processes for development and review of information in this area,
NRC believes that its current occupational exposure limits for uranium
have a sound scientific and technical basis and provide adequate
protection of public health and safety.
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\3\ Although the ACGIH concentration limit is based on
inhalation, rather than ingestion, the Sec. 20.1201(e) occupational
intake limit (which is based on the ACGIH limit) is conservative
with respect to ingestion pathways because of the significantly
lower absorption of soluble uranium into the bloodstream though the
gastrointestinal tract than through the lungs (Reference: Institute
of Medicine ``Gulf War and Health,'' copyright 2000, National
Academy Press, Washington DC).
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(2) NRC's Effluent Values Provide Adequate Protection of Public
Health and Safety.
In addition to occupational exposure limits, Appendix B to 10 CFR
part 20 also contains concentration values for release of nuclides in
effluents. Specifically, Tables 2 and 3 in Appendix B contain effluent
concentration values for releases to unrestricted areas and for
releases to sewers, respectively. The effluent and sewer concentration
values in Tables 2 and 3 are derived by reducing the radiological
occupational limits in Table 1 by a factor of 300 for air effluents, a
factor of 100 for water effluents, and a factor of 10 for sewer
discharges. These factors are applied to account for the substantially
lower radiation dose limits applicable to the general public; increased
exposure time applicable to the general public compared to occupational
exposure time; different inhalation rates; and, as appropriate, age.
Application of these reducing factors provides some assurance that the
effluent and sewer values in Tables 2 and 3 are protective from a
chemical standpoint. For example, for natural uranium and uranium-238
(two nuclides listed in 10 CFR part 20, Appendix B, which reasonably
approximate DU behavior) the radiological air effluent values in Table
2 provide protection against chemical effects of uranium because the
air effluent values are 300 times less than the radiological air
occupational limits in Table 1. In turn, the radiological air
occupational limits in Table 1 for natural uranium are similar in
magnitude to the uranium chemical limit.\4\ Further, the radiological
water effluent and sewer discharge values for natural uranium and
uranium-238 are similar in magnitude to the uranium chemical limit. As
noted in footnote 4 to this document, however, absorption of soluble
uranium is significantly lower for ingestion than for inhalation. In
addition, with regard to sewer releases, additional dilution and
removal is likely to occur prior to release to the
[[Page 43384]]
environment, either as part of the discharge process itself or during
processes which occur at the water treatment plant that processes a
licensee's sewer discharges.
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\4\ Although the chemical toxicity and radiological values are
expressed in different units, they can be compared by using the
specific activity of the form of uranium in question and by using,
as appropriate, the air intake and ingestion intake values given in
Appendix B to Part 20. Specific activity is defined as the
radioactivity of a given nuclide per gram of the material.
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Other NRC regulations further limit the amount of radioactive
material that may be released to unrestricted areas and sewers to
levels below the public dose limits upon which the values in Tables 2
and 3 are based. These requirements include Sec. 20.1101(b), which
requires that each NRC licensee use procedures and engineering controls
to achieve doses to members of the public that are ``as low as
reasonably achievable (ALARA);'' Sec. Sec. 20.1101(d) and 50.34a,
which contain requirements for implementing the ALARA principal; and
20.1301(e), which constrains allowable doses to the public, resulting
from uranium fuel cycle operations, to levels below the public dose
limits upon which the values in Tables 2 and 3 are based. In addition,
the assumptions used to derive the effluent values in Appendix B are
considered conservative with regard to any actual exposures likely to
be received because they assume continuous (24 hours/day, 7 days/week)
exposure at the facility boundary without additional dilution in the
environment. Application of these regulatory requirements and
conservative exposure assumptions serve to limit any actual exposure
likely to be received by a member of the public to levels below the
values in Appendix B to 10 CFR part 20.
Based on the above, it is unlikely that any effluent releases to
unrestricted areas or releases to sewers meeting the effluent limits in
Appendix B to 10 CFR part 20 would result in chemically significant
exposures. In addition, application of the other NRC regulations and
the conservative exposure assumptions discussed previously serve to
limit any actual exposures to levels below the values given in Tables 2
and 3 of Appendix B to 10 CFR part 20. Therefore, NRC believes that its
current limits provide adequate protection of public health and safety.
(3) NRC's Solubility Classification Has a Sound Technical Basis.
Appendix B to 10 CFR part 20 groups uranium according to solubility
classes which refer to their retention (days, weeks, years) in the
pulmonary region of the lung. The solubility classifications in
Appendix B to 10 CFR part 20 are consistent with those in FGR No. 11,
issued by the EPA in September 1988. They are also consistent with the
discussion of solubility in the U.S. Department of Health and Human
Services report on toxicological profile for uranium. The solubility
classifications in Appendix B to 10 CFR part 20 are taken from the
International Commission on Radiological Protection (ICRP) Publication
30 issued by the ICRP (published in a series of reports, supplements,
and addenda from 1979 to 1989). FGR No. 11 and ICRP Publication 30
discuss the basis for placing the uranium compounds in the different
solubility classes. ICRP is an expert body in the field of establishing
radiation standards and NRC often uses recommendations of that body in
establishing its standards in 10 CFR part 20.
(4) Studies Presented in Support of the Petition Do Not Provide a
Sufficient Reason for NRC to Revise its Current Occupational, Effluent,
and Sewer Limits, and Solubility Classification.
As noted in Section I of this document, NRC considered information
submitted in support of the petition, either as part of the petition,
as comments on the petition, or as part of the Sec. 2.206 petition on
impacts of operation of DU munitions licensees on public health and
safety. The more than 20 studies and reports referenced by the
petitioner have included information based on data from Gulf War
Veterans with exposure to DU during military deployment; results from
studies involving exposure of animals to DU; and uranium chemical
behavior in various environments. The petitioner indicated that these
studies suggested renal, reproductive, and neurotoxic effects on humans
that could occur as a result of exposure to DU. For example, the
petitioner specifically referenced excerpts from the Gulf War studies
stating conclusions, such as the risk of malformation among pregnancies
being 50 percent greater for Gulf War Veterans when compared to non-
Gulf War Veterans; and that infants conceived to Gulf War Veterans had
significantly higher birth defects (see Docketed Comment Number 2 from
James Salsman, dated June 16, 2005 (ML051680165)). The petitioner also
noted that tests on rats involving exposure to DU resulted in strong
evidence of DU accumulation in the testes and kidneys of the tested
animals. In addition to these health effects studies, the petitioner
presented data on uranium solubility in technical documents referred to
in the petition (see Section I of this document) and in references to
other studies as part of the separate petition filed under 10 CFR
2.206. As noted in Section II of this document, those commenters who
opposed the petition provided comment on studies cited by the
petitioner and did not agree that the studies cited were sufficient to
support a change to 10 CFR part 20, noting specifically that study
results from war-time exposures do not represent current occupational
exposure limits in Part 20 and that data from animal experiments were
at exposure levels well in excess of 10 CFR part 20 uranium exposure
limits. In general, these commenters indicated that the studies cited
are too premature and/or not rigorous enough in their methodology to
support a change in NRC's regulations.
NRC has concluded that, taken as a whole, the studies submitted by
the petitioner do not provide a sufficient reason to revise the
occupational exposure and effluent limits or solubility values
currently codified in 10 CFR part 20. For example, many of the studies
referenced by the petitioner investigate the correlation between health
effects and exposure to DU munitions during the Gulf War. The exposure
scenarios in these Gulf War studies included scenarios of exposure to
DU dusts, vapors, and aerosols; to permanently imbedded shrapnel
containing DU; and to a complex, potentially synergistic, set of
various agents including infectious agents, chemical warfare agents,
vaccines, and environmental pollutants. Similarly, in considering the
animal studies submitted by the petitioner, NRC notes that the studies
did not provide conclusive dose-response relationships, suggesting
instead that further specific analyses were needed. Further, the
effects described in certain studies resulted from uranium exposure in
excess of doses allowed by current regulations. Thus, these studies
would not challenge current uranium chemical or radiological limits for
humans. In addition, while the petition requested the revision of
exposure and effluent limits for all heavy metal radionuclides with
chemical hazards that exceed their radiological hazards, the supporting
information submitted by the petitioner focused exclusively on uranium.
The petitioner did not provide information or studies addressing other
heavy metal radionuclides that would cause the NRC to revise the
exposure and effluent limits currently codified in 10 CFR part 20. With
regard to the studies on solubility, NRC does not consider the data
sufficient to prompt the adoption of values different from those
recommended in FGR 11 and ICRP Publication 30 because the environments
considered in certain of the studies (e.g., war-time environment with
combustion after DU munitions hit hard targets, loss of coolant
accidents) are not comparable to the broad range of licensees regulated
under 10 CFR part
[[Page 43385]]
20, and the chemical species noted are generated by physical and
chemical interactions not associated with the broad range of license
activities covered by Part 20.
Thus, based on review of the referenced studies, NRC does not
believe that these studies provide sufficient support for a revision to
the limits and values in Part 20 because of the uncertainty in the
levels of exposure in the war arena; differences in exposure scenarios;
potential confounding effects of exposures to other environmental
pollutants; and differences between the uranium doses evaluated in the
studies and the occupational and public doses that are likely to be
received given NRC's current occupational and effluent limits. In
addition, the studies referenced do not provide dose-response
information that would be necessary to revise NRC's uranium chemical
exposure limits in a meaningful way. These studies also generally note
that caution should be used in interpreting results given and that
further investigations should be made. Other commenters on the petition
noted that data in the studies are either already addressed by existing
regulations or are premature to influence public policy with respect to
the issues NRC is considering.
(5) Relationship of this Rulemaking Petition to Petitions Submitted
Pursuant to 10 CFR 2.206.
The request made by the petitioner in this petition for rulemaking
was limited to changes to the 10 CFR part 20 occupational exposure
limits, effluent limits, and solubility categorization of heavy metal
nuclides, with a particular focus on uranium. The petitioner did not
directly raise specific concerns with regulations governing the
licensing and operations of DU munitions licensees in his rulemaking
petition. As noted in Section I of this document, on April 3, 2005, the
petitioner filed a separate petition (ML051240497) under NRC's Sec.
2.206 related to the licensing and operations of DU munitions
licensees.
The NRC denied the petitioner's initial Sec. 2.206 petition
(ML051240497) on its merits in a decision dated December 30, 2005
(ML053460450). The petitioner submitted two additional Sec. 2.206
petitions on this subject dated July 12, 2006 (ML062140659), and
December 2, 2006 (ML070080059). The NRC rejected both of these
petitions by letters dated September 26, 2006 (ML062640210), and May 4,
2007 (ML071170288), respectively. The NRC's Sec. 2.206 denial and
rejection letters referenced this rulemaking proceeding to the extent
that the petitioner's requests constituted a generic concern about the
nature and magnitude of safety hazards associated with inhaled
byproducts of DU and the adequacy of NRC regulations pertaining to
limits for ingestion and inhalation occupational values, effluent
concentrations, and releases to sewers. With regard to these generic
concerns and based on the information reviewed in evaluating this
petition for rulemaking, the NRC believes that the occupational
exposure and effluent limits for uranium contained in Part 20--which
apply to DU munitions licensees--are adequate to protect public health
and safety, and, therefore, the NRC does not believe that changes in
the regulations governing licensed use of DU munitions are required at
this time. As stated in the NRC's May 4, 2007, letter to the petitioner
(ML071170288), the NRC does not have the statutory authority to
regulate foreign or combat use of DU munitions.
IV. Conclusion
NRC is denying the petition because current NRC regulations have a
sound scientific and technical basis and provide adequate protection of
public health and safety. In developing these regulations, NRC
considered both the radiological and chemical toxicity of uranium,
ultimately adopting the TLV for uranium established by the ACGIH. The
ACGIH is an expert body in the area of chemical toxicity and federal
guidance recommends using ACGIH limits when setting chemical exposure
limits. As discussed in Section III(1) of this document, the ACGIH has
a process for updating TLVs but has not updated the uranium TLV at this
time. The information provided by the petitioner does not provide a
sufficient reason to initiate a revision of NRC's existing
requirements. Specifically, the petitioner has not presented sufficient
peer-reviewed data, pertinent to the types and levels of exposures
associated with the concentration values used in Appendix B to 10 CFR
part 20, to provide a sufficient reason for NRC to initiate a revision
of its regulations. Thus, the NRC has decided not to expend limited
resources initiating a rulemaking at this time.
For the reasons cited in this document, the NRC denies this
petition.
Dated at Rockville, Maryland, this 11th day of July, 2008.
For the Nuclear Regulatory Commission.
R.W. Borchardt,
Executive Director for Operations.
[FR Doc. E8-17108 Filed 7-24-08; 8:45 am]
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