James Salsman; Denial of Petition for Rulemaking, 43381-43385 [E8-17108]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 73, Number 144 (Friday, July 25, 2008)]
[Proposed Rules]
[Pages 43381-43385]
From the Federal Register Online via the Government Printing 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 https://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 
pdr.resource@nrc.gov.

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 frank.cardile@nrc.gov.

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

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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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