TSCA Nanoscale Materials Inventory Paper: Public Comments with EPA
Responses 

12/20/07

1) EPA-HQ-OPPT-2004-0122-0065.1 (David Rejeski, Director, Project on
Emerging Nanotechnologies)

“EPA is far too focused on the legal definition of a chemical
substances under TSCA....As J. Clarence Davies pointed out in his August
2 testimony, when TSCA was drafted in the early 1970s, no one had heard
of nanotechnology.  The TSCA paper fails to even acknowledge that the
legal constraint imposed by the definition of ‘chemical
substance’---developed nearly 40 years ago, well before the advent of
this wave of nano-engineered chemicals—is a problem.”

EPA response:

	As the commenter acknowledges, the definition of “chemical
substance” is a legal definition, one that EPA is not free to ignore
for policy reasons.  The federal government's current understanding is
that existing statutory authorities are adequate to address oversight of
nanotechnology and its applications.  As with any developing area, as
new information becomes available the federal government will adapt or
develop additional oversight approaches, as necessary, to address the
area of nanotechnology.  Congress has given EPA multiple tools in the
statute to assess and address existing chemical risks.   Several
provisions of TSCA are available as effective tools for assessing and
managing potential risks of nanoscale materials, for example:

Manage chemical substances which present “unreasonable risks” under
§6

Define through rulemaking “significant new uses” of chemical
substances and

	require notification to the Agency prior to such “significant new
uses” under    	5(a)(1)(B)

Receive statutorily required notifications of “substantial risk”
information from chemical manufacturers, processors, and distributors
under §8(e)

Require manufacturers and processors of chemical substances to submit
lists or copies of reasonably ascertainable health and safety studies
under §8(d)

Require manufacturers and processors to develop new test data on
chemicals under §4

Require manufacturers and processors to report information on chemical
use and exposures and other information under §8(a)

.  

2) EPA-HQ-OPPT-2004-0122-0013 (Greenpeace)

“Engineered nanomaterials are sufficiently different from existing
materials that they are being patented, supporting their classification
as “new” materials under TSCA. The PCAST report (May, 2005) reported
that by searching a list of nanotechnology-related keywords, the US
Patent and Trademark Office has issued over 8,600 nanotechnology-related
patents in 2003.  This represents an increase of about 50% over the
number issued in 2000. Not only the U.S. is considering these materials
to be sufficiently innovative as to be patentable; according to the
PCAST report, nanotechnology-related patents in 2003 were also issued in
Japan (926), Germany (684), Canada (244), France (183), and other
countries to a lesser degree.”

EPA response:

The criterion for determining whether chemical substances are different
for TSCA Inventory purposes is based on the TSCA definition of chemical
substance in TSCA §3(2)(A): “the term ‘chemical substance’ means
any organic or inorganic substance of a particular molecular identity,
including (i) any combination of such substances occurring in whole or
in part as a result of a chemical reaction or occurring in nature….”
 

Determining whether chemical substances are different for TSCA Inventory
listing purposes therefore is based on differences in molecular
identity.  EPA does not believe that novelty under U.S. patent law 35
U.S.C. §102, as a factor in patentable differences between engineered
nanoscale materials and their corresponding existing macroscale
materials, necessarily supports their classification as “new”
substances under TSCA since 35 U.S.C. §102 novelty does not incorporate
the concept of molecular identity in TSCA §3(2)(A).  

“We recommend that EPA develop an inventory for all engineered
nanomaterials. EPA maintains under TSCA Section 8(b) an information
Inventory that enables EPA to identify chemicals in commerce. It is
important that all engineered nanomaterials be included on an inventory
as distinct nano-scale materials, with distinct properties. The
inventory should be made publicly available in a transparent database or
repository that is accessible to both the US and International
community.”

EPA response:

The TSCA §8(b) Inventory is a list of chemical substances in commerce;
it is not an inventory of regulated materials or of materials with
specific concerns or properties.  Because EPA does not consider a
nanoscale version of a chemical to be a different chemical substance
from the macroscale version, the nanoscale version would not be listed
separately on the Inventory.  Furthermore, EPA keeps internal databases
with hazard and exposure data.  Since much of these databases include
confidential business information, they are not publicly available.  EPA
is aware of other organizations that are compiling hazard and/or
exposure databases on nanoscale substances and is interested in sharing
non-confidential data with these organizations and making such data
available to the public.  

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(J. Clarence Davies, Senior Advisor, Project on Emerging
Nanotechnologies)

“The policy enunciated in the paper flies in the face of the vast
majority of scientific evidence showing that size makes a difference. 
The whole field of nanotechnology is based on this fact—materials are
engineered at the nanoscale in order to capitalize on the change in
properties at this small scale.”

“However, the proposed TSCA inventory policy says that EPA will ignore
this difference (“referred to particle size”), noting: “the
nanoscale and non-nanoscale forms are considered the same chemical
substance because they have the same molecular identity.”  Ironically,
there is a significant disconnect between the TSCA inventory policy and
EPA’s NMSP concept paper.  The latter states that size does matter
(even providing examples of size-dependent, novel, or enhanced
properties”) and that nanomaterials present new challenges that need
to be addressed.”

‘The proposed inventory policy undermines the use of TSCA to deal with
nanomaterials.  Under the policy, the Agency is not even able to
identify which new substances are nanomaterials, much less consider the
potential adverse effects from these materials since manufacturers
submitting notices are not required to reveal that a chemical is
nano-sized.  It is a policy that removes any real hope of using TSCA to
provide adequate oversight with respect to nanotechnology.  It is a
policy that takes an already weak statue and makes it a dead letter with
respect to nanotechnology.”  

EPA response:

The TSCA Inventory is a list of chemical substances in commerce; it is
not  the mechanism by which EPA addresses concerns regarding specific
substances.  EPA therefore does not agree that there is a
“disconnect” between the Inventory and the NMSP concept papers.

	When reviewing chemical substances for potential risk to human health
and the environment under new and existing chemical sections of TSCA,
EPA does consider physical-chemical and fate properties, human health
and eco data, and exposure information.   EPA’s 28 years of experience
reviewing new chemicals has enabled the Agency to develop considerable
expertise in characterizing new chemical substances.  When reviewing
information on the chemical identity, physical properties, and the
manufacturing process for a new chemical substance, EPA generally has
adequate information or can make inquiries to the new chemical submitter
to determine if the new chemicals substance is produced in nanoscale
form. For review of nanoscale materials and as addressed in the NMSP
concept paper, EPA is interested in other relevant data including
particle size and properties.

EPA believes that its interpretation of TSCA is not only consistent with
the statute, but also one that makes considerable sense for
administration of the TSCA Inventory for the following reasons.  If EPA
were to determine that a difference in physical properties associated
with a form of a chemical substance could alone make it a new chemical
substance, it would create significant administrative and interpretive
difficulties under TSCA:

Although products of nanotechnology may exhibit properties or effects
that differ from non-nano counterparts, the differences are not always
dramatic.  Moreover, the same chemical substance can exhibit
dramatically different properties or effects in different forms in the
non-nano size range.  For example, for a number of substances (e.g.,
particulates, asbestos) important respiratory effects emerge at scales
above the nano range.. Thus, the same principles that are alleged to
make nanoscale materials eligible for new chemical treatment could apply
generally to physical forms of non-nanoscale chemicals, a concept at
odds with the structure of TSCA, and with the potential to greatly
expand both the size of the TSCA Inventory and the burdens for both
regulated entities and EPA.

The potential range of forms and physical properties associated with the
approximately 83,000 chemical substances on the TSCA Inventory is
extraordinarily large, and adoption of a policy under which such forms
and properties might render a chemical substance “new” would result
in significant uncertainty as to the Inventory status of industrial
chemicals. 

A related consideration is that there is no clear, agreed on definition
of nanotechnology or of nanoscale materials.  Nanotechnology is not so
much a scientific term with a precise meaning as it is a description of
a range of processes and materials.  EPA sees no basis in the language
of TSCA or EPA’s current regulations to make regulatory distinctions
based on whether a material is deemed a product of nanotechnology.  

Even if a focus on properties could somehow be limited to products of
nanotechnology, there can be different forms of some nanoscale
substances: different particle sizes within the nano range, different
agglomeration rates once released, different nanofilament lengths, just
to name a few.  And each may or may not have different properties.  For
example, quantum dots can be engineered at many different sizes
throughout the nanoscale to fluoresce at uniquely different frequencies.
  Under the approach suggested by the commenter, each form or size could
potentially be a different chemical substance.  The commenter suggests
that differences in properties would justify treating two materials as
different chemical substances, but EPA sees no basis in the statute or
regulations, and no basis from a scientific perspective, to delineate
how much novelty in terms of properties or other considerations would be
needed to distinguish a material as a new chemical substance.  

Declaring nanosized materials to be per se new chemicals would be
regulation with a blunt instrument.  Some nanoscale materials have been
used for centuries, such as certain pigments in stained glass windows.
As stated above, some nanoscale materials have different properties,
some do not.  TSCA gives EPA more targeted regulatory tools, such as
Significant New Use Rules under §5(a)(2), information collection under
Section 8, or testing under Section 4 that provide for greater
flexibility.  Using these tools, EPA can draw meaningful lines and
address risk and other issues associated with nanotechnology as needed. 

	The Agency’s interpretation is also consistent with the Council on
Environmental Quality’s November 8, 2007 Principles for Nanotechnology
Environmental, Health, and Safety Oversight1, which states,
“Regulation should focus where need exists and where scientific
information supports action (e.g. targeted to specific groups and
classes of materials instead of a “one-size-fits-all” approach).” 


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(Richard A. Denison, Senior Scientist, Environmental Defense)

“EPA’s approach is not required by precedent. EPA effectively says
it cannot consider particle size (and by implication, any other
nano-specific characteristics) to distinguish among substances on the
Inventory because it has not done so in the past. The first and simplest
response to this argument is that EPA may well not have needed or
recognized that it needed to make such distinctions before nanoscale
materials came along and rendered such distinctions critically
important. The real question is whether it can if it needs to. As we
have documented extensively elsewhere, EPA has ample authority under
TSCA to distinguish among chemical substances based on factors such as
physical properties and production processes. Moreover, we have shown
that it has actually done so where such factors are necessary to clearly
and unambiguously identify and name a substance or distinguish among
substances.  In its paper, EPA maintains that since EPA generally has
not considered units of matter beyond molecules, such as physical
aggregates, to be reportable under the TSCA Inventory, EPA has not used
particle size to distinguish for Inventory purposes two substances that
are known to have the same molecular identity. (page 4, emphasis added).
Putting aside EPA’s erroneous equating of molecular identity. with
chemical structure [here commenter references its May 22, 2006 letter to
EPA stating that the use of both the terms “molecular structure” and
“chemical identity” in TSCA §8(a)(2)(A) indicates that the two
terms must have different meanings],  one of EPA’s own examples cited
in the paper one page earlier (page 3) shows that it can take into
account more than strictly the chemical structure of a single molecule
in distinguishing among substances: EPA indicates that it has identified
different crystal lattice forms, each of which is comprised of the same
molecule (the example cited is the molecule titanium dioxide), as having
distinct molecular identities. It is very hard to understand why EPA was
able and willing to make the distinction in this example between two
super-molecular, aggregate (albeit regularly repeating) forms of the
same molecule, yet says it cannot do so in the case of nanoscale vs.
larger super-molecular aggregates.”  

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(George A. Kimbrell, The International Center for Technology Assessment;
Ian Illuminato Friends of the Earth)

“EPA can and has considered particle size or any other nano-specific
characteristics to distinguish nanomaterial substances from existing
chemicals. EPA has the authority under TSCA to distinguish between
chemicals based on physical properties and has done so in the past.
“Molecular identity” is not equivalent to “molecular formula.”
TSCA itself differentiates “molecular identity” from “chemical
structure.”

EPA response:

One commenter points out that “chemical identity” and “molecular
structure” are both used in TSCA § 8(a)(2), and argues that the two
terms must therefore have different meanings, and that “molecular
identity” must be different from “molecular structure.”  EPA
agrees that the terms can have distinct meanings in some circumstances,
but it does not follow that “molecular identity” is best read in a
way that allows two materials composed of the same molecules to be
considered different chemical substances based on particle size or
properties.  

Although a nanomaterial with new properties may well be considered to
have a different form than a conventional counterpart (just as liquid
water may have a different form than ice), it does not necessarily
follow that it has a different “molecular identity” (liquid water
and ice are different physical forms of the same molecule, as dictated
by temperature and pressure).  For example, some nanomaterials are
produced simply by milling an existing non-nanomaterial to a small
particle size.  This smaller sized version may have different properties
from the non-nano version, but in no sense can it be said to have a
different molecular identity, or to be a different chemical.  

As stated in the Inventory Paper, EPA views molecular identity as being
based on such structural and compositional features as the types and
number of atoms in the molecule, the types and number of chemical bonds,
the connectivity of the atoms in the molecule, and the spatial
arrangement of the atoms within the molecule.  EPA considers chemical
substances that differ in any of these structural and compositional
features to have different molecular identities. In some cases, these
structural and compositional features are relatively straightforward to
convey and this can often be done with either a chemical name or
molecular structure. In other cases, e.g., class 2 substances structural
and compositional features are not straightforward to convey.  In these
cases, chemical name and molecular structure can individually be
insufficient to represent molecular identity and as such are used in
combination, to the extent ascertainable by the PMN submitter, to
provide the best understanding of the molecular identity.

This approach is consistent with the statutory text.  EPA views
“chemical identity” as referring typically to a chemical’s formal
name (e.g., the Chemical Abstracts name based on 9th Collective Index
nomenclature rules) or, where needed, other information to identify the
chemical.  In most cases, a chemical’s CAS name conveys its structure.
 However, this will not always be the case.   EPA believes that Congress
included chemical identity in section 8(a)(2) in recognition of the
complexity of identification of commercially produced chemicals, and the
fact that a single, identifiable molecular structure will not always be
available.  In addition, Congress recognized that formal name and common
or trade name are commonly used to identify chemicals and included them
simply as pieces of identifying information.  (The fact that a chemical
is sold under two trade names, for example, would not lead to the
conclusion that each product is a different chemical.)  

	Recognition by Congress of the complexities of chemical identification
does not signal that Congress intended EPA to ignore traditional
chemistry concepts in implementing TSCA.  On the contrary, the focus on
“molecular identity” is evidence that Congress intended traditional,
molecule-based approaches to chemical identification.    Congress chose
to subject only new chemical substances to pre-manufacture review.  The
commenters’ approach would treat materials as different chemical
substances even if the molecules of which they are composed are
identical in every respect.      

Regarding the comment on super-molecular, chemical substances such as
metal oxides that have the same molecular formula (e.g., TiO2, titanium
dioxide) can have different spatial arrangements of atoms resulting in
different molecular structures in three dimensions.  Therefore they have
different molecular identities.  These different substances are not
different “super-molecular” forms, rather they are different
molecules, (e.g. orthorhombic brookite TiO2 has a different molecular
structure in three dimensions than tetragonal anatase TiO2).  EPA
therefore does not agree that it has distinguished between
“super-molecular” forms of the same molecule. 

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(Douglas Fratz, & Jane E. Wishneff, Consumer Specialty Products
Association)

“We are, however, concerned regarding one view taken by EPA in this
paper. EPA notes that it considers chemical substances to have different
molecular identities for the purposes of TSCA when they “have
different isotopes of the same elements.” CSPA has expressed in the
past its disagreement with this interpretation in terms of defining what
chemicals are “new” and therefore subject to Premanufacture
Notification (PMN) and related provisions of Section 5. Chemical
substance is defined by the statute in terms of molecular identity as
follows: 

. . . . the term “chemical substance” means any organic or inorganic
substance of a particular molecular identity including — (i) any
combination of such substances occurring in whole or in part as a result
of a chemical reaction or occurring in nature and (ii) any element or
uncombined radical. (Emphasis added). 

We believe that any attempt to define “chemical substance” in
sub-atomic terms (rather than purely in terms of molecular identities)
is inconsistent with TSCA, as well as many related existing EPA
regulations, policy statements or guidance documents. This concept was
previously considered and rejected by the Administration Law Judge in an
enforcement action against the Concord Trading Corporation in 1997, a
case in which EPA attempted to treat “depleted zinc oxide” (which
differs in isotopic distribution from normal zinc oxide, but has
identical molecular structure) as a new chemical and therefore subject
to PMN (Docket No. TSCA-94-H-19). We believe that this sixth and final
bullet relating to different isotopes should be eliminated, and chemical
substances considered to have different molecular identities for the
purposes of TSCA only when they meet one or more of the criteria in
bullets one through five.”

EPA-HQ-OPPT-2004-0122-0084.1 

(William P. Gulledge, American Chemistry Council Nanotechnology Panel)

	“The sixth example addresses isotopes stating that EPA consider
substances that are identical other than the isotopic composition to
have different molecular identities.  The Panel recognizes that the TSCA
Inventory does include some compounds where the only difference is
isotopic composition (e.g., Hydrogen/Deuterium/Tritium; Water/Deuterium
Oxide).  Nevertheless, the Panel disagrees that isotopic composition
should be considered and urges EPA to withdraw this example from this
guidance document.”

	

EPA response:

The specific issue raised by the commenters is beyond the scope of the
Inventory paper.  Nonetheless, chemical substances containing different
isotopes of a given element have different molecular weights due to the
different atomic weights of the isotopes.  Substances having definite
differences in molecular weight are considered different chemical
substances for TSCA Inventory listing purposes.  The TSCA Inventory
includes numerous separate listings for certain isotopically distinct
chemical substances (e.g., water (H2O), which has a molecular weight of
18 is distinct from deuterated water (D2O), which has a molecular weight
of 20).  Therefore they have different chemical identities and molecular
structures. 

The administrative judge in In the Matter of Concord Trading
Corporation, USEPA Docket. No. TSCA-94-H-19 (July 1997), did not reject
EPA’s interpretation that an isotopic difference can distinguish a new
chemical substance; the decision addressed only whether sufficient
information had been presented by EPA to support a motion for summary
decision in the specific case.

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(George A. Kimbrell, The International Center for Technology Assessment;
Ian Illuminato Friends of the Earth)

“First, and in general, concerning the details of the document, we
strongly disagree with EPA’s proposed approach to determining TSCA
status of nanomaterials. EPA’s proposed approach constitutes an
unnecessarily cramped statutory interpretation that creates bad policy
and ignores the scientific realities of nanomaterials….”

“Thus, “traditional” or “historical” approaches used by EPA
and upon which EPA today unfortunately purports to apply to
nanomaterials will become less, not more applicable to nanomaterials.
Putting off what is needed today for another day exacerbates the risks
to workers, health and environment from these new materials.” 

“EPA’s decision to “continue to apply its current Inventory
approaches” is unfortunate and unnecessary policy decision that is
belied by the current scientific understanding of nanotechnologies and
nanomaterials. Again, nanomaterials do not neatly fit under principles
of “traditional chemistry”, Newtonian physics, or bulk material
safety and toxicology testing methods. The adverse effects of
nanomaterials cannot be reliably predicted from the known toxicity of
the bulk material. Some experts recommend that up to sixteen
physicochemical parameters be evaluated -- a “far cry from the two or
three [parameters] usually measured” for bulk materials. Assuming
their safety or categorizing nanomaterials as equivalent to bulk
material counterparts ignores their fundamental differences and
associated hazards and unknowns.”

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(National Institute for Occupational Safety and Health)

“NIOSH is concerned that failing to consider particle size in defining
new chemicals under TSCA does not take into consideration (the basic
principles of nanoscale properties, and (2) the goal of identifying,
assessing, and managing the potential hazard of chemical
substances....Nanoscale particles exhibit enhanced reactivity compared
to their bulk counterparts because of their high-specific surface
area....This size effect on reactivity can be due to many factors (e.g.,
proportion of surface sites at edges or corners, presence of distorted
high-altered surface regions, and quantum effects)....Such factors
appear to be consistent with the types of structural and compositional
features that EPA now considers in its determination of molecular
identity.” 

EPA response:

The determination whether chemical substances are different for TSCA
Inventory listing purposes is a separate and distinct issue from EPA’s
information needs for reviewing materials for potential risk to human
health and the environment and deciding whether to take regulatory
action with respect to such materials.  In the latter, EPA does consider
information beyond what is normally relevant for bulk materials, and has
outlined a number of those types of data in the NMSP concept paper and
at the public meeting on Nanoscale Materials Characterization Peer
Consultation held in September 2007. 

Further, EPA disagrees with NIOSH’s contention that, by not
considering size in defining new chemicals under TSCA, EPA does not take
into consideration nanoscale properties and the goal of identifying,
assessing, and managing the potential hazard of chemical substances. 
When EPA identifies, assesses and manages chemical substances that are
nanoscale materials, for example as new chemical submissions under TSCA
§5 or submissions under the NMSP, the Agency will fully consider
available information on the nanoscale properties of the chemical
substances.  As noted in the paragraph above, the Agency has already
identified a number of types of nanoscale property data that would be
useful to the Agency as it conducts such reviews.  EPA also disagrees
with the assertion that size effects on reactivity are consistent with
the kinds of structural and compositional features that EPA considers in
determining molecular identity.

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(George A. Kimbrell, The International Center for Technology Assessment;
Ian Illuminato Friends of the Earth)

“The paper makes no mention of TSCA §5 significant new use rules
(SNURs) as a possible means of nanomaterial oversight under TSCA. While
there might be problems with any such approach, EPA’s failure to even
acknowledge the statutory pathway or address potential advantages or
deficiencies is further evidence of EPA’s abdication of its statutory
responsibilities to protect health and the environment.”

EPA response:

The Inventory paper is limited to issues regarding when a nanomaterial
may be considered a different chemical substance from one that is
otherwise the same except in macroscale form; the paper is not intended
to comprehensively address EPA’s regulatory authorities with respect
to nanoscale substances.  TSCA §5 (a)(2) SNURs, are addressed in the
NMSP Concept Paper. 

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(Mark G. Herwig, The General Electric Company)

“[T]he proposed Inventory status regime stops completely at the
molecular identity phase, and does not include any determinant factor
related to “novel” properties for purposes of Inventory status. 
What this translates to is a nanoscale material of a non-nano scale
material, currently Inventory listed or exempt, would not require any
further TSCA Section 5 action.  On the contrary however, where there is
reference to differing spatial arrangements of atoms of a similar
nanoscale substance (i.e. carbon nanotubes [CNT]), would in each case,
be considered a new chemical substance under TSCA, even though its
physical and chemical properties are nearly identical – thereby
requiring TSCA Section 5 action for each form of CNT manufactured or
imported.  GE strongly recommends that the Agency revisit this,
including the wealth of information exchanged during the recent Peer
Consultation on Material Characterization, in determining how nanoscale
materials should be managed under TSCA for Inventory and NMSP reporting
purposes.”

EPA response:

Chemical substances on the TSCA Inventory are not subject to TSCA §5
new chemicals requirements but may be subject to review by EPA under the
existing chemicals provisions of TSCA.  

Regarding carbon nanotubes, EPA encourages potential manufacturers to
submit a  bona fide intent to manufacture or import notice with the
required supporting data and EPA will make determinations on specific
cases.  EPA is hoping to better understand this issue based on reporting
as new chemicals under TSCA §5, and augmented with additional
information reported/developed under the NMSP

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(Mark Duvall, The Dow Chemical Company)

“EPA should provide much more detailed guidance on how to classify
nanomaterials as new or existing chemicals, and should clarify whether
carbon nanotubes are different than graphite or carbon for Inventory
purposes.”

EPA response:

The Inventory paper states that carbon nanotubes and fullerenes are
currently considered to be new chemical substances because their
molecular identities are different from the carbon allotropes (e.g.,
carbon and graphite) currently listed on the TSCA Inventory (a carbon
nanotube and a fullerene have yet to be added to the Inventory).   EPA
will provide guidance in the future on determining the TSCA Inventory
status of nanoscale substances and in the interim will provide more
clarity on a case by case basis. 

 Council on Environmental Quality’s November 8, 2007 Principles for
Nanotechnology Environmental, Health, and Safety Oversight,
http://www.ostp.gov/html/Nano%20EHS%20Principles%20Memo_OSTP-CEQ_FINAL.p
df

 See 40 CFR §720.25.

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