UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
February
15,
2006
Note
to
Reader
EPA
is
currently
reviewing
the
registration
of
three
fungicide
pesticides,
propiconazole,
triadimefon,
and
triadimenol,
to
ensure
that
they
meet
current
scientific
and
regulatory
standards.
Propiconazole,
triadimefon,
and
triadimenol
share
the
common
metabolites
1,2,4­
triazole,
triazole
alanine,
and
triazole
acetic
acid
(
also
known
as
free
triazoles).
As
required
by
the
Food
Quality
Protection
Act
of
1996
(
FQPA),
EPA
has
conducted
an
aggregate
risk
assessment
for
the
free
triazole
metabolites
to
evaluate
the
risks
posed
by
exposure
to
free
triazole
residues
as
a
result
of
pesticide
use
through
multiple
pathways
and
routes
of
exposure.
This
aggregate
assessment,
titled
"
1,2,4­
Triazole,
Triazole
Alanine,
Triazole
Acetic
Acid:
Human
Health
Aggregate
Risk
Assessment
in
Support
of
Reregistration
and
Registration
Actions
for
Triazole­
derivative
Fungicide
Compounds,"
is
included
in
the
public
dockets
for
propiconazole,
triadimefon,
and
triadimenol.

Propiconazole,
triadimefon,
and
triadimenol
also
share
a
common
metabolite,
1,2,4­
triazole,
with
several
triazole­
derivative
pharmaceutical
compounds.
Thus,
EPA
must
consider
the
incremental
impact
of
exposure
to
1,2,4­
triazole
pesticide
residues
to
individuals
using
triazole­
derivative
pharmaceutical
products.
To
this
end,
EPA
is
currently
working
with
the
U.
S.
Food
and
Drug
Administration
(
FDA),
which
has
regulatory
authority
for
drug
products,
to
develop
a
co­
exposure
determination
for
1,2,4­
triazole
residues
that
could
result
from
concurrent
exposure
to
triazole­
derivative
pharmaceutical
and
pesticide
products.
This
co­
exposure
determination
will
provide
the
basis
of
safety
findings
reflecting
the
joint
perspectives
of
FDA
and
EPA,
and
will
inform
a
decision
by
both
Agencies
about
whether
appropriate
measures
are
needed
to
reduce
exposures
from
one
or
both
sources
of
1,2,4­
triazole
residues.
