FIFRA Scientific Advisory Panel Considers Nanosilver

Date01 December 2009
12-2009 NEWS & ANALYSIS 39 ELR 11143
FIFRA Scientif‌ic Advisory
Panel Considers Nanosilver
by Lynn L. Bergeson
Lynn L. Bergeson is Managing Director of Bergeson & Campbell, P.C., a
Washington, D.C., law rm focusing on conventional and engineered nanoscale
chemical, pesticide, and other specialty chemical product approval and regulation,
environmental health and safety law, chemical product litigation, and associated
business issues. She is also President of e Acta Group, L.L.C., and e Acta
Group EU, Ltd, with oces in Washington, D.C., and Manchester, UK.
On November 3-5, 2009, the
Federal Insecticide, Fungicide,
and Rodenticide Act (FIFRA)
Scientic Advisory Panel (SAP) met
“to consider and review a set of scien-
tic issues related to the assessment of
hazard a nd exposu re associated with
nanosilver and other nanometal pes-
ticide products.” e decision to con-
vene an SAP was nomina lly motivated
by t he U.S. Environmental Protection
Agency’s (EPA’s) need to consider four
applications pending at the Oce
of Pesticide Programs (OPP) seeking
registration of products containing
nanosilver-based active ingredients.
e nano silver products, which
would take the form of textile addi-
tives, polymers, coatings, and/or
plastics, would be used to protect a
treated product from microorgani sms
or to impart antimicrobial activity to
a treated materia l. Accordingly, they
would b e used in the same man ner a s
some of the currently registered sil-
ver products, including those used as
material s preservative s and antimicro-
bial pesticides. Notably, many of t he
110 currently registered silver-bas ed
products actually contain nanosilver.1
1. As noted in the SAP Background Paper, EPA “has
information suggesting that there are other pes-
ticide products currently in the marketplace that
contain nanosilver.” e Silver Nanotechnology
Working Group (SNWG), an industry group
formed to promote the benecial uses of silver
nanoparticles that testied before and submit-
ted comment to the SAP, went so far as to claim
that “all EPA registered silver products through
to 1994 were nanoscale” (emphasis added) and
“the majority of existing registered silver products
Unmentioned in either the Septem-
ber 16, 2009, Federal Register notice
announcing the public meet ing or the
SAP Background Document EPA pre-
pared in connection with the meeting
is a May 2008 petition submitted by
the International Center for Technol-
ogy A ssessment (ICTA) a nd others
requesting, among other actions, that
EPA classify nanosilver as a pesticide,
require the registration under FIFRA
of nanosilver products, and determine
that nanosilver is a new pesticide that
requires a new FIFRA pesticide registra-
tion (available at
nanoaction/doc/CTA_nano -silver%20
Core Issue
EPA states in its Background Paper that
“the current state of the science does not
contain sucient information to deter-
mine denitively whether (and, if so, to
what extent) various forms of nanosilver
particles may cause toxic eects beyond
those attributable to the release of silver
ions.” In light of this, the threshold ques-
tion before the SAP relates to whether
EPA can make its safety nding under
FIFRA that a pesticide product will not
cause “unreasonable adverse eects on
the environment” with respect to the
four pending applications.
According to EPA, the registration
applicants claim that “the mode of
action for nanosilver is the same as for
are nanosilver, including the algaecides and water
lters that have been used for decades.”
silver in that the release of silver ions
is the source of a ntimicrobial activ-
ity.” Because the pesticidal mode of
action of nanosilver is the same as for
conventionally sized silver, the poten-
tial hazards to human health and the
environment resulting from the use of
nanosilver as a pesticide will therefore
be the same as from the use of silver.
EPA likened the registrants’ argu ment
to that of the so-called 0-hypothesis put
forward by S. Wijnhoven et al. (2009).
e 0-hypothesis states that the toxic
eects of nanosilver are proportional to
the activity of free silver ions released by
the nanoparticles. e question, then,
for FIFRA regulatory purposes becomes
whether sucient data and information
exist to validate the hypothesis. is
requires a two-step process: (1) deter-
mine whether nanosilver par ticles enter
the body; and (2) determine whether
nanosilver releases silver ions and to
what extent the ions will be absorbed.
EPA further states that registration
applicants posit that there will be no
or only trivial levels of human expo-
sure to nanosilver particles since these
particles will not leach from nished
products. As a result, any toxic eect to
humans would be the result of exposure
Lynn L. Bergeson
Copyright © 2009 Environmental Law Institute®, Washington, DC. reprinted with permission from ELR®,, 1-800-433-5120.

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