UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON
D.
C.,
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
February
7,
2006
PC
Code
074002
DP
Barcode:
D318020
MEMORANDUM
SUBJECT:
EFED s
drinking
water
assessment
for
sodium
cyanide
in
relation
to
fumigation
of
truck
trailers
and
chamber
TO:
James
Doty,
Risk
Manager
Reviewer
Robert
McNally,
Risk
Manager
Special
Review
and
Reregistration
Division
(
7508C)

FROM:
Faruque
Khan,
Environmental
Scientist
Environmental
Risk
Branch
V
Environmental
Fate
and
Effects
Division
(
7507C)

APPROVED
BY:
Jean
Holmes,
Acting
Branch
Chief
Environmental
Risk
Branch
V
Environmental
Fate
and
Effects
Division
(
7507C)

This
memorandum
presents
a
drinking
water
assessment
of
the
use
of
sodium
cyanide
as
a
fumigant
in
truck
trailers
and
enclosed
chambers.
Sodium
cyanide
is
known
as
cyanide
of
sodium,
hydrocyanic
acid
sodium
salt.
It
hydrolyzes
readily
to
gaseous
hydrogen
cyanide
(
HCN)
when
dissolved
in
water
or
in
contact
with
moisture.
Gaseous
HCN
is
intended
to
be
used
in
fumigating
chambers,
truck
trailers
and
other
temporarily
enclosed
containers
for
citrus
fruits
to
satisfy
State,
Federal
and
International
quarantine
requirements.
An
application
rate
of
one
ounce
of
sodium
cyanide
applied
results
in
six
ounces
of
HCN
gas
per
1000
ft3.

Environmental
Fate
and
Effects
Division
(
EFED)
does
not
anticipate
significant
exposure
from
sodium
cyanide
as
well
as
hydrogen
cyanide
in
surface
water
and
ground
water,
when
it
is
used
as
a
fumigant
under
controlled
delivery
system
of
gaseous
HCN
into
an
airtight
enclosure
as
described
in
the
sodium
cyanide
label
(
SLA
CA
840006)
and
accepted
by
the
State
of
California
Department
of
Pesticide
Regulation.
Residual
HCN
will
be
vented
from
the
treated
containers
through
a
exhaust
system.
In
a
recent
air
monitoring
study
(
MRID
#
46648901),
eight­
hour
time­
weighted
average
concentration
of
HCN
in
ambient
air
after
fumigation
of
citrus
truck
trailers
was
zero
ppm.
Based
on
the
above
fumigation
operation,
and
due
to
the
high
vapor
pressure
(
742
mm
Hg
@
25
°
C)
and
Henry's
Law
Constant
(
1.33
x
10­
4
atm­
m3/
mole)
of
HCN,
redeposition
of
volatilized
HCN
in
surface
water
does
not
appear
to
be
significant,
thus
suggesting
that
contamination
of
surface
waters
and
ground
water
by
HCN
is
unlikely.
