Page
1
of
20
UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
MEMORANDUM
June
21,
2006
SUBJECT:
I.
D.
No.
TRED­
0024­
26059:
Boric
Acid/
Sodium
Salts
of
Boric
Acid.
Phase
4:
Response
to
Public
Comments
for
the
Health
Effects
Division
(
HED)
Chapter
of
the
Tolerance
Reassessment
Eligibility
Decision
(
TRED)
Decision
Document.

PC
Codes:
011001
(
boric
acid),
011102
(
sodium
tetraborate
decahydrate),
011110
(
sodium
tetraborate
pentahydrate),
011112
(
sodium
tetraborate
anhydrous),
011103
(
disodium
octaborate
tetrahydrate),
011107
(
disodium
octaborate
anhydrous),
011104
(
sodium
metaborate)
DP
Barcodes:
D320882,
D320893
FROM:
Linnea
J.
Hansen,
Ph.
D.,
Biologist
Toxicology
Branch
Health
Effects
Division
(
7509P)
AND
Jeff
Evans,
Senior
Biologist
Chemistry
and
Exposure
Branch
Health
Effects
Division
(
7509P)

TO:
Nathan
Mottl/
Laura
Parsons
(
RM
51)
Reregistration
Branch
I
Reregistration
Division
(
7508P)

THROUGH:
Louis
Scarano,
Ph.
D.
Chief,
Toxicology
Branch
Health
Effects
Division
(
7509P)

I.
CONCLUSIONS
The
Health
Effects
Division
(
HED)
of
the
EPA
Office
of
Pesticide
Programs
(
OPP)
has
reviewed
public
comments
submitted
during
the
Phase
3
public
comment
period
on
the
HED
Chapter
of
the
Tolerance
Reassessment
Eligibility
Decision
(
TRED)
document
on
boric
acid
and
sodium
salts
of
boric
acid
(
Docket
ID
#
EPA­
HQ­
OPP­
2005­
0062).
Responses
to
specific
comments
are
provided
below
under
the
Discussion
Section
of
this
memorandum.
The
comments
pertinent
to
the
hazard
characterization
have
been
addressed
by
Linnea
Hansen
and
comments
on
exposure
have
been
addressed
by
Jeff
Evans.
Page
2
of
20
A
number
of
revisions
to
the
HED
TRED
document
per
the
submitted
comments
have
been
made,
as
appropriate.
A
more
detailed
response
to
comments
is
given
below
under
the
Discussion
Section.
The
risk
assessment
endpoints
and
overall
characterization
of
toxicity
remain
unchanged
at
this
time.
Revised
MOEs
have
been
calculated
for
some
of
the
exposure
scenarios
and
assessments
of
hand­
to­
mouth
postapplication
exposures
resulting
from
wood
treatment
uses
have
been
added.

Toxicology
data
requirements
have
been
amended
from
the
original
TRED
document
posted
for
public
comment
and
no
further
studies
are
required
at
this
time.
HED
has
determined
that
a
28­
day
inhalation
toxicity
study
in
the
rat
is
not
required,
but
may
be
required
at
a
later
date
if
sufficient
inhalation
exposure
concerns
are
raised
from
new
uses
or
new
incident/
epidemiology
data.
It
is
requested,
however,
that
any
new
toxicity
studies
on
boric
acid/
sodium
borates
that
may
be
conducted
at
the
request
of
other
regulatory
agencies
also
be
submitted
to
the
US
EPA
for
review.

Additional
data
are
requested
to
refine
risk
estimates
for
post­
application
uses
having
MOEs
below
100.

II.
ACTION
REQUESTED
The
Health
Effects
Division
(
HED)
was
requested
to
respond
to
comments
received
on
the
HED
Chapter
of
the
Tolerance
Reassessment
Eligibility
Decision
(
TRED)
for
boric
acid
and
sodium
salts
of
boric
acid.
This
document
was
available
for
public
comment
from
February
22,
2006
through
April
24,
2006.
Comments
were
received
from
numerous
registrants
of
products
containing
boric
acid
and/
or
sodium
borate
salts,
as
well
as
from
the
Canadian
Pesticide
Management
Regulatory
Agency
(
PMRA).

III.
DISCUSSION
COMMENTS
ON
THE
HAZARD
CHARACTERIZATION
Comments
on
the
hazard
characterization
portion
of
the
HED
TRED
Chapter
were
submitted
by
the
Canadian
PMRA,
US
Borax
and
Nisus
Corporation.
Where
similar
comments
from
different
sources
were
received,
they
are
addressed
in
a
single
response.

1.
Comment­
need
for
quantitative
risk
assessment:
Nisus
Corporation
questioned
the
need
to
conduct
a
quantitative
risk
assessment
for
boric
acid
and
sodium
borates,
based
on
several
criteria
(
low
acute
toxicity,
low
dermal
absorption,
lack
of
significant
bioaccumulation,
rapid
mammalian
excretion,
lack
of
well­
documented
human
chronic
toxicity).

Agency
response:
The
Agency
recognizes
that
boric
acid
and
sodium
borates
meet
many
of
the
criteria
of
low­
risk
chemicals,
as
outlined
above.
Furthermore,
boron
is
a
naturally
occurring
element
found
in
food
and
drinking
water
and
to
which
humans
are
constantly
exposed
at
low
levels.
However,
in
multiple
experimental
animal
species,
boron
has
shown
the
potential
to
cause
significant
reproductive
toxicity,
including
testicular
atrophy,
and
developmental
toxicity
Page
3
of
20
in
multiple
experimental
animal
species.
Developmental
toxicity
has
been
observed
at
doses
that
do
not
cause
maternal
toxicity
and
effects
have
been
reported
following
single
exposures.
Effects
to
the
male
reproductive
tract
in
experimental
animals
have
been
induced
following
short­
term
exposures.
Based
on
these
findings,
the
Agency
therefore
determined
that
a
quantitative
risk
assessment
should
be
prepared
to
evaluate
the
contribution
of
pesticidal
and
other
consumer
use
to
total
boron
exposure.

2.
Comment­
additional
boric
acid
studies
and
published
studies:
US
Borax
and
PMRA
noted
that
the
TRED
document
and
the
1994
Reregistration
Eligibility
Decision
document
did
not
include
several
studies
on
boric
acid
in
the
toxicology
profile.
Other
published
studies
were
also
mentioned.

Agency
response:
Summaries
of
additional
studies
on
boric
acid
have
been
incorporated
into
the
document
and
other
studies
considered
in
this
response
phase.

3.
Comment­
use
of
dog
dietary
studies
for
endpoint:
US
Borax
and
PMRA
disagreed
with
the
EPA's
decision
to
use
the
older
dog
dietary
studies
on
boric
acid
and
borax
as
the
basis
for
toxicity
endpoints,
based
on
poor
quality
of
the
studies
and
uncertainties
regarding
the
NOAEL/
LOAEL.

Agency
response:
The
Agency
concurs
that
the
dog
38­
week
and
2­
year
dietary
studies,
conducted
in
the
1960'
s
prior
to
current
study
conduct
guidelines,
do
not
meet
the
current
standards
for
guideline
studies
and
are
problematic
to
interpret.
In
evaluating
the
data
for
endpoint
selection,
the
decision
to
use
the
dog
study
was
based
on
joint
consideration
of
the
available
dog
studies,
the
toxicology
database
as
a
whole
and
the
levels
of
dietary
background
exposure
for
humans
relative
to
risk
assessment
endpoint
values.
The
dog
studies
used
to
derive
the
endpoints
in
this
assessment
were
used
by
IRIS
in
the
evaluation
conducted
prior
to
the
2004
review,
when
a
newer,
well­
conducted
rat
developmental
toxicity
endpoint
was
selected
as
the
basis
for
the
RfD.
In
1995,
the
HED
RfD
Committee
also
reviewed
boric
acid/
sodium
borate
salts
and
determined
that
the
dog
studies
should
be
used
for
the
RfD,
with
the
developmental
toxicity
study
in
the
rat
as
a
co­
critical
study.
The
NOAELs
identified
in
these
studies
are
similar
(
8.8
mg/
kg/
day
for
the
dog
study
and
9.6
mg/
kg/
day
for
the
rat
study).
Although
interpretation
of
the
dog
studies
was
clearly
complicated
by
the
small
number
of
animals
evaluated
and
background
effects,
testicular
effects
could
be
reasonably
established
in
the
38­
week
and
90­
day
studies.
The
NOAEL
of
8.8
mg/
kg/
day
identified
by
the
study
authors
in
the
2­
year
dog
studies
was
used
in
this
assessment
(
see
also
comment
4
regarding
rationale).

If
EPA
had
chosen
to
consider
the
dog
study
unacceptable
and
use
another
study,
an
additional
uncertainty
factor
would
need
to
be
added
to
the
endpoint
selected
to
account
for
lack
of
a
major
guideline
study
that
may
be
the
most
sensitive
species
for
testicular
toxicity.
For
example,
an
additional
factor
of
3
for
database
uncertainty
added
to
the
rat
reproductive
NOAEL
of
25­
27
and
the
standard
100X
uncertainty
factor
would
achieve
a
value
essentially
the
same
as
the
endpoint
identified
in
this
TRED.
Assessment
of
boron
hazard
also
requires
consideration
of
background
intake
via
diet
and
drinking
water.
Use
of
an
uncertainty
factor
of
1000,
or
identification
of
a
lower
NOAEL,
would
provide
a
value
for
risk
assessment
comparable
to
current
estimates
of
daily
dietary
intake
for
humans.
Although
additional
boron
intake
via
diet
Page
4
of
20
and
drinking
water
was
not
accounted
for
in
the
test
animals
of
the
available
studies,
and
would
effectively
increase
the
NOAEL,
EPA
did
not
consider
it
appropriate
to
establish
an
RfD
falling
within
the
range
of
normal
moderate
human
dietary
intake.

4,
Comment­
consistency
with
EPA
IRIS
endpoint:
US
Borax
and
PMRA
noted
that
the
2004
Agency
IRIS
review
of
boron
selected
a
rat
developmental
toxicity
as
the
critical
study
for
the
RfD.
US
Borax
considered
the
IRIS
RfD
the
appropriate
endpoint
to
use
for
this
risk
assessment
based
on
the
Agency's
stated
goals
of
achieving
consistency
in
risk
assessments
among
programs.

Agency
response:
HED
selected
the
testicular
effects
in
the
dog
as
the
critical
study
for
risk
assessment
(
1)
to
allow
characterization
of
potential
risks
to
different
subpopulations
that
may
not
include
pregnant
females
at
different
durations
of
exposure
and
(
2)
to
establish
a
conservative,
but
not
unrealistic
endpoint
for
such
assessments.
PMRA
and
other
reviewing
agencies
(
e.
g.,
EPA
IRIS,
WHO)
have
elected
to
use
the
rat
developmental
toxicity
study
in
support
of
the
RfD
for
boron
due
to
its
higher
quality
as
a
study.
However,
as
pointed
out
by
US
Borax,
the
NOAELs
used
are
essentially
the
same
(
8.8
mg/
kg/
day
vs.
9.6
mg/
kg/
day),
with
differences
in
the
uncertainty
factors
used
(
IRIS
used
66,
whereas
this
assessment
uses
100).

5.
Comment­
database
uncertainty:
PMRA
added
an
extra
uncertainty
factor
of
10
in
calculation
of
their
RfD
to
account
for
uncertainties
in
the
database
from
study
inadequacy
and
increased
sensitivity
of
offspring
in
the
developmental
toxicity
studies.

Agency
response:
EPA
chose
what
it
considers
a
reasonable
endpoint,
that
is
probably
somewhat
conservative,
to
conduct
its
hazard
assessment.
It
is
noted
that
PMRA
used
an
incremental
RfD
approach
to
assess
additional
exposure
to
boron
via
pesticidal
and
consumer
products
containing
boric
acid/
sodium
borate
salts
that
is
above
dietary
background
levels,
whereas
EPA
values
for
risk
assessment
were
inclusive
of
background
exposure
levels.
Addition
of
a
3­
10x
database
uncertainty
factor
to
EPA's
endpoint
would
result
in
a
risk
assessment
value
similar
to
calculated
ranges
of
human
normal
daily
dietary
intake,
which
EPA
considers
unreasonably
low.
In
contrast,
since
PMRA
is
using
an
incremental
approach,
acceptable
additional
boron
exposure
levels
from
such
products
would
be
expected
to
be
relatively
small.

5.
Comment­
revised
boron
intake
values
for
dog
studies:
US
Borax
noted
that
boron
equivalent
intake
values
for
the
dog
studies
were
determined
using
standard
dietary
conversion
factors.
For
the
dog
38­
week
and
2­
year
studies
used
in
deriving
the
endpoint,
US
Borax
prepared
boron
average
daily
intake
values
derived
from
food
consumption
and
body
weight
data
from
the
original
study
report,
resulting
in
slightly
higher
values
than
the
original
NOAEL
of
8.8
mg/
kg/
day
(
mean
for
the
endpoint
is
9.6
mg/
kg/
day
and
10.9
mg/
kg/
day
for
borax
and
boric
acid,
respectively).

Agency
response:
The
recalculated
boron
intake
values
provided
by
US
Borax
are
noted
by
the
Agency,
but
no
changes
were
made
to
the
current
assessment
since
the
differences
from
the
original
NOAEL
are
small
and
do
not
significantly
affect
the
conclusions
of
the
assessment.
However,
the
data
calculations
prepared
by
US
Borax
were
submitted
and
will
be
reviewed;
the
new
values
may
be
used
for
future
risk
assessments.
Page
5
of
20
6.
Comment­
endpoint
for
child
risk
assessment:
US
Borax
questioned
whether
use
of
the
testicular
effects
endpoint
was
appropriate
for
a
child
risk
assessment.

Agency
response:
The
Agency
considered
this
issue
in
the
determination
of
endpoints
for
different
populations.
It
was
concluded
that
the
endpoint
should
be
retained
for
exposure
to
children
because
there
was
uncertainty
as
to
the
potential
effects
of
boron
on
the
immature
reproductive
organs
(
male
or
female)
and
on
the
development
of
the
reproductive
tract.

7.
Comment­
adequacy
of
database:
In
addition
to
the
dog
studies,
PMRA
considered
numerous
other
studies
inadequate
for
hazard
characterization
and
identified
different
NOAELs/
LOAELs
for
several
studies.
Problems
with
the
reproductive
toxicity
studies
and
evaluation
of
sensitivity
of
reproductive
organs
of
offspring
were
discussed:
PMRA
did
not
concur
with
EPA's
conclusion
that
offspring
do
not
appear
to
show
increased
sensitivity
to
testicular
effects.

Agency
response:
EPA
agrees
with
PMRA
that
many
of
the
studies
on
boric
acid/
sodium
borate
were
not
performed
to
current
standards.
In
considering
the
entire
database,
EPA
determined
that
a
reasonable
assessment
of
toxicity
could
be
conducted
for
regulatory
purposes
using
this
data,
despite
the
inadequacies
in
these
studies.
Many
were
classified
as
nonguideline/
acceptable,
using
the
current
HED
study
acceptability
nomenclature,
to
indicate
that
although
the
studies
did
not
meet
guideline
standards,
there
was
sufficient
data
to
provide
a
reasonable
hazard
characterization
for
use
in
risk
assessment.
In
lieu
of
requesting
additional
data,
which
the
Agency
does
not
consider
likely
to
provide
a
lower
endpoint
value
(
although
new
studies
would,
of
course,
be
useful
to
establish
certain
NOAELs/
LOAELs
in
these
studies),
an
endpoint
was
selected
(
8.8
mg/
kg/
day
in
the
dog)
that
is
considered
reasonable
for
assessment
of
risk.
EPA
identified
different
NOAELs/
LOAELs
than
PMRA
for
some
of
the
studies,
for
example,
based
on
lack
of
a
clear
dose­
response
or
different
interpretation
of
other
findings
in
the
study
reports.

EPA
concurs
with
PMRA
that
there
were
significant
deficiencies
in
the
rat
reproductive
toxicity
studies.
However,
new
studies,
which
may
provide
important
information
regarding
offspring
and
parental
reproductive
effects
and
relative
sensitivities
of
males
and
females,
are
unlikely
to
identify
a
significantly
lower
endpoint
compared
to
the
current
dog
endpoint
used
in
this
assessment.
EPA
considers
the
mouse
study
by
NTP,
which
included
crossover
mating
evaluations,
supportive
of
lack
of
a
significantly
increased
risk
to
offspring
based
on
lack
of
a
lower
reproductive
LOAEL
for
the
later
generations.
Additionally,
the
NOAEL
for
all
generations
is
approximately
2.5­
fold
higher
than
the
dog
endpoint.
Within
the
context
of
the
data
limitations
outlined
by
PMRA,
the
data
support
lack
of
significantly
increased
risk
to
offspring.

8.
Comment­
increased
fetal
sensitivity
in
rabbit:
PMRA
considered
agenesis
of
the
gallbladder,
seen
in
the
developmental
toxicity
study
on
rabbits,
to
be
a
treatment­
related
effect
and
determined
that
increased
fetal
sensitivity
was
observed,
based
on
this
finding
at
a
dose
below
the
maternally
toxic
dose.
In
the
review
of
this
study,
HED
did
not
consider
this
effect
to
be
treatment­
related.
Page
6
of
20
Agency
response:
HED
has
revisited
this
study,
conducted
by
NTP.
Doses
tested
were
0,
62.5,
125
or
250
mg/
kg/
day
boric
acid.
Agenesis
of
the
gall
bladder
was
not
observed
in
control
or
low
dose
fetuses
but
was
seen
in
3/
153
fetuses
(
20
litters
examined)
at
the
mid
dose
and
2/
14
fetuses
at
high
dose
(
6
litters
examined).
The
incidence
can
be
considered
to
be
increased
at
high
dose,
while
at
mid
dose,
the
increase
is
marginal.
Other
malformations
were
observed
at
the
high
dose
in
this
study.
The
study
authors
noted
the
gallbladder
effects
as
"
potentially"
related
to
boric
acid
treatment,
but
did
not
use
this
finding
to
establish
a
developmental
LOAEL,
stating
that
"
No
definitive
evidence
of
developmental
toxicity
was
observed
at
125
mg/
kg/
day.
The
low
dose
(
62
mg/
kg/
day)
was
clearly
nontoxic
to
both
the
maternal
animal
and
the
developing
conceptus.
Thus,
the
maternal
and
developmental
NOAELs
were
considered
to
be
125
mg/
kg/
day."

Agenesis
of
the
gallbladder
in
rabbits
is
a
relatively
uncommon
malformation
in
rabbit,
but
is
occasionally
observed
in
untreated
animals.
At
this
time,
the
Agency
will
retain
the
developmental
toxicity
NOAEL
at
the
mid
dose,
but
will
note
the
finding
in
the
study
summary.

9.
Comment­
cancer
classification:
PMRA
disagreed
with
the
classification
of
boric
acid/
sodium
borates
as
"
not
likely
to
be
carcinogenic
to
humans"
and
supported
the
classification
of
"
inadequate
information
for
classification
of
carcinogenicity
to
humans"
based
on
study
inadequacy.
PMRA
noted
that
the
rat
studies
by
Hazleton
Laboratories
on
boric
acid
and
borax
did
not
contain
a
complete
tissue
evaluation
and
did
not
provide
a
tabulated
evaluation
of
neoplastic
findings
and
the
mouse
National
Toxicology
Program
(
NTP)
study
tested
two
dose
levels
and
showed
increased
mortality
in
males
in
the
treated
groups.
In
addition,
the
US
EPA
IRIS
review
of
boron
in
2004
also
considered
the
data
inadequate
to
make
a
determination.

Agency
response:
In
assessing
whether
boric
acid/
sodium
borates
were
likely
to
be
carcinogenic
to
humans,
HED
made
a
weight­
of­
the­
evidence
determination
based
on
the
available
carcinogenicity
data
in
experimental
animals
(
the
NTP
mouse
study
and
2­
year
dietary
studies
on
boric
acid
and
sodium
metaborate
in
the
rat
by
Hazleton
Laboratories),
together
with
other
information,
such
as
genotoxicity
data
and
human
exposure.
HED
considered
the
NTP
mouse
study
adequate
for
evaluation
of
carcinogenicity.
Although
only
two
test
levels
were
conducted,
toxicity
was
sufficient
to
achieve
the
MTD
and
HED
did
not
consider
the
increased
mortality
in
treated
males
to
be
of
sufficient
magnitude
to
affect
conclusions.
NTP
concluded
that
there
was
no
evidence
of
carcinogenicity
to
mice
in
this
study.

While
the
rat
studies
on
boric
acid
and
borax
were
not
performed
to
standard
carcinogenicity
testing
guidelines,
both
studies
did
examine
most
tissues
typically
evaluated
in
a
cancer
study.
The
NTP,
in
deciding
to
test
only
mice,
also
made
the
determination
that
rats
had
already
been
adequately
tested
in
that
study.
There
is
no
evidence
that
boron
has
genotoxic
potential
and
boron
is
rapidly
excreted
following
ingestion.
Human
epidemiology
data
are
limited,
but
the
constant
exposure
via
diet
and
drinking
water
to
this
naturally
occurring
element
with
no
evidence
of
an
increase
in
the
incidence
of
neoplasia
suggests
that
boron
is
not
likely
to
be
a
carcinogen
to
humans
or
to
other
species.

10.
Comment­
characterization
of
hematological
findings:
US
Borax
considered
decreases
in
red
blood
cell
parameters
noted
as
anemia
in
some
studies
to
be
subclinical
and
possibly
Page
7
of
20
secondary
to
other
toxicity.
Standardization
of
terminology
throughout
the
TRED
was
requested
(
referred
to
in
different
parts
of
the
document
as
"
anemia,"
"
slight
anemia"
or
"
mild
anemia").

Agency
response:
Terminology
for
the
effects
on
red
blood
cells
has
been
changed
to
either
"
slight
hematological
changes"
or
a
description
of
the
affected
parameters.
The
Agency
generally
considers
reductions
exceeding
10%
in
red
blood
cell
parameters
to
be
potentially
adverse.
Effects
on
red
blood
cell
parameters
were
identified
at
dose
levels
showing
other,
more
significant
effects
and
by
themselves
were
not
used
to
determine
study
LOAELs.

11.
Comment­
rat
maternal
toxicity
LOAEL
selection:
PMRA
noted
that
one
of
the
rat
developmental
toxicity
studies
identified
the
maternal
toxicity
LOAEL
based
on
decreased
gravid
weight,
which
was
probably
due
to
fetal
loss.

Agency
response:
EPA
concurs
with
PMRA
and
the
maternal
LOAEL
has
been
changed
to
a
NOAEL.

12.
Comment­
need
for
repeat­
exposure
inhalation
toxicity
study:
US
Borax
questioned
the
need
for
a
28­
day
inhalation
toxicity
study.
They
cited
acute
inhalation
studies
(
MRIDs
43500701,
44383601)
showing
that
boric
acid
was
in
toxicity
category
III
rather
than
II
(
highest
dose
tested
was
2000
mg/
L,
the
limit
dose).

Agency
response:
HED
has
reconsidered
this
data
requirement.
At
this
time,
a
28­
day
inhalation
toxicity
study
in
the
rat
will
not
be
required,
based
on
consideration
of
the
Registrant's
comments,
and
will
retain
use
of
an
oral
study
for
inhalation
exposure
risk
assessment.
However,
should
new
uses
and/
or
other
inhalation
epidemiologic,
experimental
or
incident
data
suggest
that
additional
inhalation
toxicity
data
is
needed
to
better
assess
hazard
from
inhalation
exposure,
this
study
requirement
may
then
be
reconsidered.

13.
Comment­
upgrade
of
UDS
study:
US
Borax
submitted
experimental
data
in
support
of
the
unscheduled
DNA
synthesis
study
(
MRID
42038903)
to
upgrade
it
to
Guideline­
Acceptable.

Agency
response:
HED
has
reviewed
the
submitted
information
and
has
upgraded
the
study
to
acceptable.
A
new
study
is
not
required.

14.
Comment­
relevancy
of
HOX
gene
alterations
to
humans:
US
Borax
did
not
consider
alteration
of
the
HOX
gene
in
published
rodent
developmental
toxicity
studies
to
be
relevant
to
human
risk
assessment
based
on
observation
of
the
effect
at
high
dose
levels
(
500
mg/
kg/
day).

Agency
response:
The
effect
of
boric
acid
on
HOX
gene
expression
during
development
was
not
evaluated
for
dose­
response
and
lower
dose
levels
were
not
evaluated.
The
LOAEL
and
NOAEL
for
this
finding
are
therefore
not
known
at
this
time.
HED
will
add
a
statement
to
the
TRED
noting
this
fact.

15.
Comment­
characterization
of
endocrine
disruptor
potential:
US
Borax
and
PMRA
do
not
consider
boric
acid/
sodium
borates
to
have
the
potential
to
disrupt
the
endocrine
system.
US
Page
8
of
20
Borax
noted
lack
of
epidemiological
support
for
this
effect;
both
US
Borax
and
PMRA
noted
published
data
suggesting
lack
of
endocrine
disruption
as
the
mechanism
of
testicular
toxicity
and
inhibited
spermiation
(
Fail
et
al.,
1998).

Agency
response:
The
current
language
on
endocrine
disruption
will
be
retained
due
to
lack
of
conclusive
data
regarding
effects
on
endocrine
hormones.
Although
the
Fail
et
al.
paper
suggests
that
the
testicular
hormonal
effects
in
male
rats
are
secondary
to
cytotoxicity,
this
mechanism
has
not
been
established
and
there
is
also
no
data
on
other
endocrine
hormones,
e.
g.,
estrogens.
This
section
is
intended
to
reflect
uncertainties
in
the
available
information,
rather
than
to
suggest
that
boron
is
an
endocrine
disruptor.

16.
Comment­
vomiting
in
acute
oral
study
in
dog:
US
Borax
noted
that
for
the
acute
oral
toxicity
study
in
the
dog
(
MRID
40692304),
it
should
be
noted
that
dosing
in
dogs
appears
to
be
limited
by
vomiting
at
higher
dose
levels.

Agency
response:
HED
has
noted
this
in
the
TRED
document.

17.
Comment­
dermal
irritation
of
sodium
metaborate:
US
Borax
requested
that
in
Section
4.1.1.4
of
the
TRED
document,
it
should
be
noted
that
sodium
metaborate,
but
not
boric
acid
or
other
sodium
borate
salts,
is
a
dermal
irritant.

Agency
response:
HED
has
made
this
change
in
the
TRED
document.

18.
Comment­
additional
boron
dietary
intake
values:
US
Borax
requested
consideration
of
a
reference
by
Rainey
et
al.
(
1999)
regarding
daily
boron
intake
in
the
United
States.

Agency
response:
HED
has
reviewed
this
article
and
provided
values
for
boron
intake
from
the
article
in
Section
3.2
of
the
TRED
document.

19.
Comment­
correction
of
boron
equivalent
calculations:
PMRA
noted
corrections
to
be
made
in
the
boron
equivalent
calculations
in
the
mouse
carcinogenicity
study
on
boric
acid
and
chronic
rat
study
on
borax.

Agency
response:
EPA
has
made
corrections
as
appropriate.

COMMENTS
ON
THE
EXPOSURE
ASSESSMENT
Comments
on
the
exposure
assessment
for
this
tolerance
reassessment
were
received
by
US
Borax,
Nisus,
MeadWestvaco,
Searles
Valley
Minerals,
Industrial
Minerals
Association,
Biolab,
Inc.,
National
Pest
Management
Association,
McIntyre
Associates,
Cole
Research
and
Development
and
Canadian
PMRA.

1.
PMRA
Comment:
9444­
150
(
aerosol
cans):
The
density
was
used
to
convert
14
ounces
to
pounds
ai,
assuming
fluid
ounces.
However,
based
on
the
product
label,
the
can
appears
to
be
Page
9
of
20
14
ounces
(
mass),
397
g
(
i.
e.,
unit
of
mass
not
volume).
Based
on
conversions
of
ounces
(
mass),
397
g
product
*
20%
*
79.4
g
ai
use
per
day
of
0.17
lb
ai,
rather
than
0.27
lb
ai.

Agency
Response:
The
Agency
agrees
and
will
make
the
appropriate
changes
to
the
TRED.
It
should
be
noted
that
the
source
document
for
the
TRED
(
Exposure
and
Risk
Assessment
on
Lower
Risk
Pesticide
Chemicals,
Boric
Acid
and
its
Sodium
Salts)
will
also
need
to
be
corrected.

2.
PMRA
Comment:
In
the
Exposure
Table
of
Appendix
3,
the
source
of
the
inhalation
unit
exposure
value
is
not
clear.
The
PHED
aerosol
inhalation
unit
exposure
value
of
1300
µ
g/
lb
ai
was
not
used.
The
source
of
the
value
of
2400
µ
g/
lb
ai
handled
should
be
indicated.

Agency
Response:
The
PHED
value
of
1300
µ
g/
lb
ai
handled
is
an
occupational
inhalation
PHED
value
while
the
residential
value
(
also
from
PHED)
of
2400
µ
g/
lb
ai
is
from
the
aerosol
spray
subset.

3.
PMRA
Comment:
70908­
3
and
48369­
2
(
dust
via
shaker
can):
the
source
of
the
inhalation
unit
exposure
value
for
shaker
can
(
value
870
µ
g/
lb
ai)
which
is
found
in
the
Exposure
Table
of
Appendix
3.0
should
be
presented.
A
default
approach
for
shaker
can
scenarios
may
involve
assuming
a
percentage
of
total
amounts
applied
(
as
outlined
in
the
Residential
SOPs),
however,
it
appears
that
other
data
were
used
in
this
assessment.

Agency
Response:
A
unit
exposure
value
was
taken
from
a
proprietary
study
(
applying
dusts
with
a
shaker
can)
and
will
be
identified
in
the
revised
TRED.
The
study
is
Merricks,
D.
Larry
(
2001)
Determination
of
Dermal
(
hands
and
forearms)
and
Inhalation
Exposure
to
Disulfoton
Resulting
from
Residential
Applications
of
Bayer
Advanced
Garden
2
in
1
Systemic
Rose
and
Flower
Care
to
Shrubs.
MRID
45333401
February
8,
2001.

4.
PMRA
Comment:
1677­
191
(
granular
bait
dispersed
by
hand):
The
density
was
used
to
convert
ounces
to
a
mass
of
product
applied,
however,
the
product
label
indicates
that
the
product
is
"
12
ounces
of
340
g."
At
½
a
can
(
or
170
g),
the
amount
handled
per
day
is
170
g
*
54%
=
91.8
g
or
0.202
lb
ai.

Agency
Response:
The
Agency
agrees
and
will
make
the
appropriate
changes
to
the
TRED.
It
should
be
noted
that
the
source
document
for
the
TRED
(
Exposure
and
Risk
Assessment
on
Lower
Risk
Pesticide
Chemicals,
Boric
Acid
and
its
Sodium
Salts)
will
also
need
to
be
corrected.

5.
PMRA
Comment:
5185­
461
(
m/
l
granular
via
spoon
of
cup):
The
source
of
the
inhalation
unit
exposure
value
is
not
clear.
In
the
Exposure
Table
of
Appendix
3.0,
it
is
cited
as
45
µ
g/
lb
ai,
whereas
in
PHED
surrogate
tables
for
granular
open
mixing/
loading,
inhalation
unit
exposure
value
is
1.7
µ
g/
lb
ai.

Agency
Response:
The
1.7
value
is
for
occupational
assessments.
The
Agency
relied
on
a
proprietary
study
to
assess
the
residential
use
of
applying
a
granular
via
spoon
or
cup.
The
study
used
was:
Fipronil,
Worker
Exposure
Study
During
Application
of
Regent
20GR
in
Banana
Plantation.
[
MRID
452507­
02]',
P.
Pontal,
1996.
The
TRED
will
be
revised
to
include
this
citation.
Page
10
of
20
6.
PMRA
Comment:
1083­
1,
64405­
6,
79628­
1
(
trigger­
pump
sprayer):
Source
of
inhalation
unit
exposure
value
for
trigger­
pump
sprayer
on
Table
3.0,
page
71,
is
not
clear.

Agency
Response:
The
Agency
has
relied
on
a
proprietary
study
to
assess
this
use.
The
study,
Carbaryl
Mixer/
Loader/
Applicator
Exposure
Study
During
Application
of
RP­
2
Liquid
(
21%),
Sevin
Ready
to
Use
Insect
Spray
or
Sevin
10
Dust
to
Home
Garden
Vegetables.
MRID
444598­
01
D.
Merricks.
(
1997).
The
TRED
will
be
revised
to
include
this
citation.

7.
PMRA
Comment:
Product
79628­
1
is
a
wood
preservative
product
in
which
pretreatment
may
take
place
to
wood
foam
composite
structural
components
as
such,
it
is
not
anticipated
that
a
trigger
sprayer
is
a
representative
application
method.
PMRA
also
noted
this
product
contains
99.98%
active
ingredient
Agency
Response:
The
Agency
agrees
and
will
remove
the
scenario
from
the
revised
assessment.

8.
PMRA
Comment:
71635­
5
(
m/
l/
a
with
paint
brush):
The
label
for
this
product
(
a
wood
preservative)
indicates
that
it
may
also
be
applied
by
spray
application
however
this
application
wasn't
included
for
this
product.

Agency
Response:
Paint
brush
scenario
results
in
higher
exposures
and
lower
MOEs.
Because
the
MOE
for
the
paint
brush
scenario
was
greater
than
100,000,
the
other
scenario
was
not
included.

9.
PMRA
Comment:
Inputs
of
1hour/
event
(
adult
and
2
hours/
event
(
child))
are
not
consistent
with
the
Residential
SOP
90th
percentile
value
(
5
hours/
event
for
both
children
and
adults)
It
was
noted
that
the
Swimmodel
inputs
in
the
TRED
that
1
hr/
event
was
a
90th
percentile
value.

Agency
Response:
The
draft
Children's
Specific
Exposure
Factors
Handbook
recommends
an
exposure
duration
of
60
minutes
per
event
(
based
on
one
event
per
month)
for
contact
with
water
while
swimming.
This
value
is
described
as
"
upper"
while
a
0.5
hours
per
event
was
described
as
"
central".
These
values
are
for
people
responding
to
the
NHAPS
Survey
question
"
in
the
past
month,
did
you
swim
in
a
freshwater
pool?".

10.
PMRA
Comment:
The
contact
rate
(
water
ingested)
of
2.5E­
2
L/
hr
(
adults)
is
not
consistent
with
the
Residential
SOP;
Residential
SOP
recommends
0.05
L/
hr
for
both
adults
and
children.
Clarification
of
the
source
of
the
alternative
value
for
adults
is
recommended.
Page
11
of
20
Agency
Response:
The
following
input
values
are
in
the
current
SWIMODEL:

Ingestion
rate
(
mL/
hr)
Competitive
Non­
competitive
Child
(
7­
10
years)
25
(
1/
2
the
rate
for
noncompetitive
swimmers,
as
recommended
by
the
American
Chemistry
Council
(
ACC),
2002)
50
EPA,
1989
and
1997;
ACC,
2002­
based
on
an
EPA
pilot
study)

Child
(
11­
14)
25
(
1/
2
the
rate
for
noncompetitive
swimmers,
as
recommended
by
the
ACC,
2002)
50
EPA,
1989
and
1997;
ACC,
2002­
based
on
an
EPA
pilot
study)

Adults
12.5
(
1/
2
the
rate
used
for
non
competitive
swimmers
as
recommended
by
ACC,
2002)
25
(
ACC,
2002
 
based
on
EPA
pilot
study)

11.
PMRA
Comment:
Inhalation
rate
for
adults
for
moderate
activity
is
1.6
m3/
hr,
based
on
revisions
to
the
Residential
SOPs
(
Feb,
2001);
1.0
m3/
hr
was
used
for
adults
in
the
TRED.

Agency
Response:
It
was
assumed
that
the
use
of
boric
acid
as
an
algaecide
was
primarily
intended
for
residential
swimming
pools.
The
following
table
presents
the
inhalation
rates
in
the
current
version
of
the
SWIMODEL:

Inhalation
rate
(
m3/
hr)
Competitive
Non­
competitive
Child
(
7­
10
years)
1.9
(
Table
5­
23
of
the
Exposure
Factors
Handbook
(
EFH);
short
term
exposures,
heavy
activity)
1.0
(
Table
5­
23
of
EHF;
short­
term
exposures,
light
activity)

Child
(
11­
14)
1.9
(
Table
5­
23
of
the
EFH;
short
term
exposures,
heavy
activity
)
1.0
(
Table
5­
23
of
EFH:
short­
term
exposures,
light
activity)

Adults
3.2
(
Table
5­
23
of
the
EFH:
short
term
exposures,
heavy
duty)
1.0
(
Table
5­
23
of
EHF;
short­
term
exposures,
light
activity)
Page
12
of
20
Given
the
low
vapor
pressure
of
Boric
Acid
compounds
(
as
pointed
out
by
other
commenters),
the
Agency
did
not
include
the
inhalation
route
for
this
scenario
in
the
revised
TRED.

12.
PMRA
Comment:
The
90th
percentile
for
body
weight
was
used
for
the
swimming
assessments;
it
would
be
useful
to
identify
why
a
90th
percentile
was
chosen
for
this
parameter.

Agency
Response:
In
the
revised
TRED
a
body
weight
of
70
kg
will
be
used
for
males/
females.

13.
PMRA
Comment:
Child
physiology
values
(
inhalation
and
body
weight)
are
based
on
child
aged
7­
10
or
11­
14.
It
is
recommended
to
include
an
assessment
of
a
child
aged
6
to
determine
the
risk
associated
with
this
age
group
or
lower,
as
lower
body
rates
and
similar
water
ingestion
rates
are
anticipated
to
result
in
low
MOEs.

Agency
Response:
The
actual
SWIMODEL
does
not
include
a
default
for
children
aged
6
years
or
younger.
However,
since
a
dermal
assessment
is
not
needed
and
inhalation
MOEs
are
sufficiently
high
(
range)
the
resultant
risk
estimates
are
unlikely
to
be
significantly
different.
For
inhalation
in
particular
since
these
compounds
have
low
vapor
pressures.

14.
PMRA
Comment:
The
water
concentration
for
spa
appears
to
be
higher
than
that
of
a
pool.
An
assessment
for
a
spa
may
be
warranted
due
to
differences
in
concentration
(
inputs
such
as
water
ingestion
and
time
spent
may
be
justified
to
be
different
between
spas
and
pools)
or
a
justification
for
not
including
this
scenario
should
be
provided.

Agency
Response:
A
maximum
application
rate
of
0.0045
lb
ai/
gal
is
applied
to
pools
(
label
5185­
461)
and
a
maximum
application
rate
of
0.0031
lb
ai/
gal
is
made
to
spas
(
label
5185­
492).
HED
believes
there
is
less
potential
for
swimming
(
and
subsequent
ingestion
of
water)
for
the
spa
scenario.
Its
inclusion
does
not
appear
to
be
justified
at
this
time.

15.
PMRA
Comment:
In
the
case
of
the
boric
acid
inert,
the
source
of
the
value
for
chemical
concentration
of
boric
acid
in
water
was
not
clear.

Agency
Response:
It
was
assumed
that
the
concentrations
for
the
inert
products
were
1%
of
the
application
rate
for
boric
acid
when
used
as
an
algaecide.
We
note
an
error
in
Table
6.3c
indicating
a
water
concentration
of
54,000
µ
g/
L.
The
value
should
be
540,000
µ
g/
L.
The
latter
value
was
used
as
an
input
value
to
the
SWIMODEL.
Therefore,
the
exposure
calculations
are
correct
(
likewise,
the
inert
source
should
be
5,380
µ
g/
L).

16.
PMRA
Comment:
It
is
difficult
to
match
the
scenarios
and
use
rates
presented
in
Table
6.3d
with
the
application
scenarios
under
Table
63a,
as
the
references
to
product
labels
are
not
listed
as
in
Table
6.3a.

It
appears
that
the
use
rates
used
in
this
post­
application
assessment
reflect
rates
examined
in
the
applicator
assessment.
It
was
not
clear
whether
other
products,
used
by
commercial
applicators,
may
result
in
high
use
rates
per
unit
area
and
possibly
result
in
higher
post­
application
exposure
potential.
Page
13
of
20
Agency
Response:
It
is
believed
that
exemplary
labels
representing
all
uses
were
presented
in
the
document.

17.
PMRA
Comment:
Based
on
comments
on
application
rate
in
the
handler
exposure
assessment
(
i.
e.
application
rate
calculations
base
on
ounces
in
mass
rather
than
volume),
the
application
rate
used
in
the
children's
exposure
assessment
for
the
aerosol
application
and
the
granular
bait
dispersed
by
hand
may
be
different.

It
appears
that
the
application
rate
for
the
first
carpet
spray
for
disodium
octaborate
tetrahydrate
(
based
on
64405)
should
be
0.003
lb
ai/
ft2
rather
than
0.0003
lb
ai/
ft2,
based
on
the
following
equation:

1
gallon/
750
ft2
*
0.32
g/
mL
*
1000
mL/
L
*
3.78
L/
gallon
*
2.2
lb/
kg
*
1
kg/
1000
g
=
0.0035
ft2
Agency
Response:
The
above
equation
does
not
take
into
account
the
percent
active
ingredient
(
8.5%).

18.
PMRA
Comment:
Footnote
c
is
missing
in
the
table;
it
appears
that
footnote
e
should
be
footnote
d
and
footnote
in
the
table
should
be
c.

Agency
Response:
The
Agency
agrees
with
this
comment
and
will
make
the
corrections.

19.
PMRA
Comment:
The
scenarios
under
disodium
octaborate
and
disodium
octaborate
tetrahydrate
scenarios
are
confusing
as
they
are
identified
as
a
spray
carpet
scenario,
however,
these
products
(
71653­
5,
79629­
1)
are
wood
preservation
products.
These
scenarios
should
be
clarified
and
the
applicability/
uncertainty
associated
with
the
inputs
derived
from
carpet/
hard
surface
scenarios
should
be
describe
(
this
may
be
corrected
in
the
memo
specific
to
wood
preservation
uses).

Agency
Response:
The
post
application
assessment
for
disodium
octaborate
tetrahydrate
is
for
product
64405­
6
(
carpet
treatment).
When
the
TRED
and
source
document
were
prepared,
the
post
application
exposure
potential
for
exposure
to
the
wood
preservative
products
appeared
to
be
low.
Although
the
labels
suggest
that
the
types
of
materials
to
be
treated
are
for
interior
construction
such
as
framing
and
siding
materials,
there
is
a
possibility
that
some
of
these
products
may
end
up
being
used
in
decking.

20.
PMRA
Comment:
The
handler
exposure
and
risk
calculation
only
examines
one
product
(
72468­
2).
Based
on
the
labels
cited
in
the
HED
chapter,
other
wood
preservative
products
were
assessed
however
these
products
were
not
discussed
in
the
supplementary
memo
(
i.
e.
products
71653­
5,
79628­
1).
It
is
not
clear
whether
the
product
which
is
presented
in
this
supplementary
assessment
is
representative
of
all
other
wood
preservative
labels
(
e.
g.
has
highest
rate
per
unit
area
of
application).
Based
on
the
label,
it
appears
possible
that
this
product
may
be
applied
by
methods
other
than
low
pressure
spray
(
for
example
it
appears
that
paintbrush
may
be
another
method
of
application),
alternative
methods
of
application
could
also
be
considered.
Page
14
of
20
Only
product
72468­
2
was
included
in
this
toddler
post­
application
assessment,
with
only
one
rate
being
examined
(
the
label
appears
to
be
ambiguous
about
rates
for
various
methods
of
treatment).
It
is
not
clear
if
this
assessment
is
to
be
representative
of
all
other
wood
preservative
products
containing
boron.

The
toddler
post­
application
assessment
only
assesses
exposure
associated
with
consumer
application
of
boron
products.
Several
of
the
products
identified
in
the
assessment
(
including
72468­
2,
79628­
1
and
71653­
5)
include
pressure
treatment
uses,
which
are
not
relevant
for
the
residential
handler
exposure
assessment,
but
may
result
in
residential
post­
application
exposure.
It
is
not
clear
if
the
assessment
which
is
presented
is
lonely
meant
to
cover
spray/
surface
applications
or
if
it
is
meant
to
address
pressure
treatment
applications.
If
it
is
meant
to
address
pressure
treatment
applications,
further
discussions
of
the
uncertainties
associated
with
extrapolating
exposure
from
a
surface
application
rate
to
a
product
which
penetrates
the
wood
is
required.

Agency
Response:
The
post
application
assessment
of
wood
treatments
was
not
conducted
in
the
source
document
for
the
TRED
(
Exposure
and
Risk
Assessment
on
Lower
Risk
Pesticide
Chemicals,
Boric
Acid
and
its
Sodium
Salts).
This
oversight
was
not
identified
until
late
in
the
TRED
process.
In
the
revised
TRED,
the
worst
case
scenario
(
in
situ
deck
treatment)
will
be
used
to
assess
both
pressure
treated
lumber
and
decks.
It
is
believed
that
data
already
generated
by
the
registrants
can
be
used
to
refine
these
scenarios.
These
data
will
need
to
be
submitted
and
reviewed.

21.
Industry
Minerals
Association
 
North
America;
U.
S.
Borax
Inc.;
Nisus
Corporation
Comment:
Carpet
Crack
and
Crevice
Assessment­
The
assessments
for
carpet
applications
must
be
distinguished
from
crack
and
crevice
applications.
This
is
necessary
because
the
methods
of
use
(
and
resulting
exposure)
differ
significantly.
The
different
methods
of
use
are
incorporated
into
the
official
pesticide
registration
and
the
required
labels.
The
risk
assessments
should
be
based
on
the
labels
as
currently
registered
and
should
consider
the
label
instructions.

Regarding
carpet
applications,
we
agree
that
there
are
insufficient
data
to
properly
characterize
exposures.
In
the
absence
of
data,
we
agree
that
conservative
assumptions
should
be
utilized.
The
request
for
data
on
carpet/
hand
transfer
in
Section
10.3
should
be
helpful
in
reducing
uncertainties.

Regarding
crack
and
crevice
applications,
we
do
not
agree
that
the
resulting
exposure
is
excessive
or
that
additional
data
would
be
useful
to
reduce
uncertainties.
The
assessment
should
be
revised
to
reflect
the
following
issues:

 
Crack
and
crevice
applications
are
not
broadcast
over
large
surface
areas;
 
Labels
for
crack
and
crevice
treatment
clearly
indicate
removal
of
all
visible
product
by
brushing
into
cracks
or
sweeping
up;
 
Additionally,
the
application
rates
used
for
estimating
crack
and
crevice
exposure
are
based
on
rate
and
methods
for
carpet
application
(
lbs/
sf);
 
Data
from
carpet/
hand
transfers
would
not
clarify
crack
and
crevice
exposures;
and
Page
15
of
20
 
Two
of
the
labels
referenced
in
the
carpet/
crack
and
crevice
risk
assessment
are
inappropriate
for
consideration.

Based
on
the
label
instruction
for
crack
and
crevice
applications
as
currently
required
by
EPA,
exposure
to
boron
is
mitigated
by
removal
of
all
visible
product.
Additionally,
label
instruction
to
limit
application
to
areas
which
are
inaccessible
to
children
and
pets
further
mitigates
exposure
concerns.
Consideration
of
these
factors
would
result
in
a
more
accurate
assessment
of
exposure
to
boron
from
crack
and
crevice
applications.

Agency
Response:
See
response
to
Comment
#
22
below.

22.
U.
S.
Borax
Inc.
Comment:
U.
S.
Borax
provided
comments
similar
to
those
provided
by
IMA­
NA.
However,
U.
S.
Borax
noted
that
label
directions
instruct
users
of
crack
and
crevice
products
to
"
not
apply
in
living
spaces
accessible
to
children
and
pets."
They
assert
that
this
language
was
imposed
by
the
1993
Boric
Acid
RED
and
as
such
would
result
in
minimal
amounts
of
product
to
be
available
for
exposure
to
animals
or
pets.

Agency
Response:
The
Agency
believes
that
a
simple
study
can
be
conducted
to
address
both
broadcast
and
crack
and
crevice
applications.
Crack
and
crevice
applications
result
in
deposition
patterns
ranging
from
high
(
e.
g.,
along
baseboards)
to
low
(
center
of
the
room).
Thus,
a
young
child
has
the
potential
to
come
in
contact
with
both
concentrations.
Hand
removal
efficiency
data
in
the
form
a
wipe
or
hand
press
study
would
be
very
helpful
to
refine
both
scenarios.
HED
believes
that
label
language
directing
the
user
to
remove
visible
residues
(
e.
g.
brushing
into
cracks
or
sweeping
up)
will
reduce
but
not
eliminate
residues
(
likewise
common
sense
language
to
apply
the
product
to
areas
inaccessible
to
children
and
pets).
At
a
minimum,
surface
wipe
and
or
hand
press
(
cotton
gloves
over
latex)
residue
study
based
on
compliance
with
broadcast
and
crack
and
crevice
label
directions
should
be
sufficient
to
address
both
uses.

23.
Industry
Minerals
Association
 
North
America
Comment:
The
risk
assessment
should
distinguish
between
the
application
of
a
ready­
to­
use
solution
by
brush
or
spray
to
decks
in
situ
(
which
is
the
scenario
addressed
by
the
TRED
assessment)
and
pressure
impregnation
treatments
of
dimensional
lumber
done
by
producers
of
treated
wood.
Lumber
treatment
is
carried
out
at
specifically
designed
facilities
with
pressure
chambers
that
directly
drive
the
preservative
into
the
wood
using
conditions
of
temperature,
pressure
and
vacuum.
This
different
mode
of
treatment
limits
the
amount
of
surface
residues
available
for
potential
exposure.
A
simple
acknowledgement
that
the
TRED
scenario
addresses
the
application
of
ready­
to­
use
solutions
but
not
the
commercial
pressure
impregnation
treatment
scenario
would
help
avoid
confusion
about
the
scope
of
the
assessment.

The
assessment
should
be
revised
to
reflect
the
following
issues:
 
Dislodgability
(%)
of
the
active
ingredient
from
the
deck
surface;
 
Penetration
of
the
preservative
into
wood;
 
Sealant
mitigation
of
exposure;
and
 
Calculation
of
toddler
exposure
from
sprayed
decks.
Page
16
of
20
Based
on
the
label
instruction
exposure
to
boron
is
mitigated
by
absorption
into
the
wood
and,
as
indicated
by
EPA,
sealing
the
wood.
Consideration
of
these
factors
would
result
in
a
more
accurate
assessment
of
exposure
to
boron
from
disodium
octaborate
tetrahydrate
treated
wood
by
spray
application.

Agency
Response:
A
post
application
assessment
was
not
conducted
for
the
wood
treatment
products
in
either
the
Exposure
and
Risk
Assessment
on
Lower
Risk
Pesticide
Chemicals
­
Boric
Acid
and
its
Sodium
Salts
or
the
TRED.
This
oversight
was
not
identified
until
late
in
the
TRED
process
and
addressed
minimally
in
a
follow
up
memorandum
dated
January
6,
2006.
When
post
application
data
addressing
non
dietary
ingestion
pathways
(
for
both
the
pressure
treated
and
in
situ
wood
treatments)
are
submitted,
these
scenarios
can
then
be
refined.

Regarding
the
presumption
that
sealants
mitigate
exposure
potential,
HED
has
recently
learned
from
the
Antimicrobials
Division
that
they
are
not
considering
the
impact
of
coatings/
sealants
in
wood
treatment
risk
assessments.
It
is
believed
that
the
wipe
data
presented
by
various
commenters
would
be
helpful
in
addressing
these
exposure
scenarios.
We
encourage
that
these
or
other
similar
data
be
submitted.

24.
Industrial
Minerals
Association
 
North
American
Comment:
The
assessment
of
swimming
pool
applications
should
be
revised
to
reflect
appropriate
use
of
the
residential
postapplication
exposure
model,
concentrations
of
active
ingredients
and
relevant
acute
end
points.

The
assessment
should
be
revised
to
reflect
the
following
issues:
 
Description
of
products
and
application
methods;
 
Dermal
and
inhalation
pathways
 
MOE
Calculation
based
on
potential
dose
rate
(
PDR)
vs.
average
daily
dose
(
ADD).

The
application
rate
input
into
the
model
(
5,400,000
µ
g/
liter)
is
off
by
a
factor
of
10,
one
decimal
place.
This
computational
error
increases
the
margin
of
exposure
(
MOE)
to
an
acceptable
level.
The
TRED
assessment
should
acknowledge
that
the
calculations
are
based
on
maximal
conditions
 
100%
active
with
the
highest
application
rate,
and
therefore
incorporates
a
conservative
approach
to
the
estimated
risk.
Appendix
6.0
for
the
exposure
scenario
for
swimmers
should
not
include
the
dermal
and
inhalation
pathways.
Recalculation
of
the
ADD
demonstrates
the
MOE
for
this
broadcast
application
of
sodium
tetraborate
pentahydrate
(
100%
a.
i.)
using
conservative
Tier
1
based
exposure
screening
tool
(
SWIMODEL)
is
well
above
the
minimum
value
of
100
in
the
TRED.

Agency
Response:
The
application
input
to
the
SWIMODEL
was
5.4
E+
05
and
was
further
adjusted
by
percent
boron
in
the
label
specific
active
ingredient
statement
(
14.85%
boron
in
sodium
tetraborate
pentahydrate)
in
Table
6.3c.
We
previously
noted
the
typographical
error
in
Table
6.3c
indicating
a
concentration
of
54,000
µ
g/
L.

A
non­
dietary
ingestion
endpoint
was
selected
for
short
term
exposure
(
1
to
30
days).
Therefore
a
single
day
exposure
(
the
PDR)
must
be
used
in
lieu
of
the
amortized
value
(
ADD)
generated
by
the
SWIMODEL.
Page
17
of
20
25.
MeadWestvaco
Comment:
The
commenter
submitted
measurements
of
boron
in/
on
lumber
(
yellow
pine
deck
boards)
pressure
treated
with
a
boric
acid
compound.
These
measurements
coupled
with
the
exposure
assumptions
presented
in
the
addendum
to
the
Boric
Acid
TRED
indicate
Margins
of
Exposure
(
MOE)
above
100
for
post
application
exposure.

Surface
Boron
Concentrations
and
Margin
of
Exposure
for
Toddlers
Measurement
units
Protected
Boards
5­
Month
Weathered
Boards
Mass
concentration1,
ppb
B
4,960
450
Surface
conc.
2
µ
g
B/
sq
ft
10,340
940
MOE3,
dimensionless
580
6,400
1.
Inductively
coupled
plasma
(
ICP)
analysis
of
a
thin
(
1/
16­
in)
slice
of
wood
from
upper
surface;
2.
One
fiber
diameter
depth
(
40
µ
m)
and
density
of
treated
wood
(
35/
ft2)
used
in
calculations;
3.
Margin
of
Exposure
for
Toddler
Non­
Dietary
Ingestion
using
EPA
estimation
method
reported
in
their
25Jan06
document
"
supplement
to
HED
Chapter "
which
uses
a
10%
dislodgeable
estimate.

The
commenters
acknowledge
the
lack
of
data
available
to
address
the
pressure
treated
wood
uses
and
in
situ
wood
surface
treatments.
In
the
table
shown
above,
they
assert
that
MOEs
greater
than
100
can
be
achieved
if
the
Agency
relies
on
the
surface
concentration
measurements
indicated
by
footnote
two,
and
the
10
percent
dislodgeable
estimate
used
in
the
TRED
(
indicated
by
footnote
three).

In
a
separate
letter
dated
April
21,
2006,
MeadWestvaco
indicated
non­
dietary
ingestion
MOEs
ranging
from
~
5800
to
210,000
for
exposure
to
pressure
treated
lumber
when
relying
on
data
presented
in
J.
D.
Lloyd's
hand
press
study
(
1996).

Agency
Response:
The
Agency
welcomes
the
opportunity
to
review
the
data,
however
we
note
that
both
the
data
addressing
the
pressure
treated
wood
and
the
in
situ
treatments
are
only
presented
in
the
comments
in
summary
form.
Both
studies
need
to
be
submitted
for
review.
In
addition,
the
dislodgeable
data
discussed
in
J.
D.
Lloyd's
paper
will
need
to
undergo
a
human
subject's
review.
The
study
is
reportedly
based
on
a
study
involving
intentional
human
exposure
(
bare
hand
press)
to
solutions
containing
and
wood
treated
with
a
boric
acid
compound.
The
Agency
will
use
dislodgeable
estimates
presented
in
the
aforementioned
studies
and
will
consider
the
submissions
as
confirmatory.

26.
U.
S.
Borax
Inc.;
Searles
Valley
Minerals
Comment:
The
U.
S.
Borax
Corporation
provided
information
commonly
understood
in
the
wood
preservative
industry
regarding
the
American
Wood­
Preservers'
Association
(
AWPA)
penetration
standards
for
aqueous
based
or
waterborne
preservatives.
For
disodium
octaborate
tetrahydrate
(
DOT)
uses
(
Formosan
and
non
Formosan
species
of
termites),
the
registrant
asserts
that
retention
depths
of
0.4
inches
(
non
Formosan)
and
0.6
inches
(
Formosan),
coupled
with
chemical
retentions
(
lbs/
ft3)
are
required.
These
retentions
are
0.25
(
non
Formosan)
and
0.43
(
Formosan)
when
in
accordance
with
the
Page
18
of
20
AWPA
standard.
By
using
the
minimum
retention
standard
and
the
calculations
presented
in
the
TRED
(
in
situ)
the
commenters
estimate
that
75%
of
the
amount
applied
is
available
on
the
surface
(
rather
than
the
100%
assumed
in
the
TRED).

The
U.
S.
Borax
Corporation
and
Searles
Valley
Minerals
also
had
issue
with
HED's
statements
regarding
the
effectiveness
of
wood
sealants.
They
note
that
two
contradictory
statements
regarding
wood
sealing
were
made:

In
the
exposure
section;
"
the
extent
to
which
this
sealing
mitigates
boron
transfer
to
children's
hands
is
unknown
at
this
time";
and
On
Page
2
of
the
TRED
"
painting
lumber
is
likely
to
mitigate
exposure
to
borate
products
in
treated
wood."

Agency
Response:
The
Agency
will
consider
using
the
25%
reduction
in
surface
availability
based
on
the
commenter's
understanding
of
the
penetration
of
topical
wood
treatments.
The
Agency
also
recognizes
that
sealing
may
impact
the
surface
availability
of
the
substance
used
to
treat
the
wood.
However
at
the
time
those
statements
were
made,
HED
was
not
aware
of
any
information
or
data
demonstrating
the
impact
of
sealing.
This
uncertainty
was
captured
in
the
two
statements
quoted
by
the
commenter.
Whether
the
two
statements
are
contradictory
to
us
seems
to
be
a
matter
of
judgment,
however
we
regret
any
misunderstanding.
More
importantly,
HED
has
learned
that
the
Agency's
Antimicrobial
Division
does
not
accept
sealing
as
a
means
to
mitigate
exposure
in
risk
assessments.

27.
U.
S.
Borax
Inc.
Comment:
The
registrant
recalculated
non­
dietary
ingestion
risks
using
75
percent
surface
availability,
and
the
percent
dislodgeablility
values
presented
in
J.
Lloyd,
1996.
Margins
of
exposure
based
on
wet
hand
dislodgability
and
dry
hand
dislodgeablilty
are
177
and
591
respectively.

Agency
Response:
The
Agency
will
revise
the
assessment
to
include
the
75
percent
surface
availability.
Additional
refinement
will
be
made
after
the
data
are
submitted
and
reviewed.
These
data
will
need
to
be
formally
submitted.

28.
U.
S.
Borax
Inc.;
BioLab,
Inc.
Comment:

The
registrants
recalculated
swimmer
ingestion
rates
for
children
by
using
the
SWIMODEL
ADD
estimates
rather
than
the
SWIMODEL
PDR
estimates
used
in
the
TRED.
The
PDR
values
are
daily
exposure
estimates.
The
ADD
estimates
are
amortized
values
based
on
number
of
days
swimming
per
year
times
the
number
of
years
swimming
divided
by
365
days
a
year.
They
also
assert
that
estimates
of
exposure
for
inhalation
and
dermal
routes
should
not
be
made
due
to
the
low
vapor
pressure
and
low
dermal
absorption
rate
respectively.
They
present
a
number
of
MOE
estimates
for
three
different
pool
water
concentrations.
By
using
ADD
estimates
from
the
SWIMODEL
and
the
different
concentrations,
MOEs
ranged
from
~
1700
to
6200.

Agency
Response:
The
Health
Effects
Division
(
HED)
uses
PDR
or
daily
exposure
estimates
when
comparing
exposure
to
short­
term
endpoints
(
1
to
30
days).
In
the
toxicology
chapter
the
Page
19
of
20
toxicity
study
was
determined
to
be
appropriate
for
assessing
short
term
exposures.
Therefore
HED
will
continue
using
the
PDR
instead
of
the
ADD.

Dermal
exposure
was
not
assessed
in
the
TRED
although
these
estimates
were
displayed
in
the
SWIMODEL
output
files.
HED
is
reconsidering
its
decision
to
include
the
inhalation
route
in
the
revised
assessment.
However
we
note
that
the
risk
assessment
showed
these
exposures
to
be
of
low
concern.

HED
will
recalculate
the
non­
dietary
ingestion
values
for
other
pool
concentrations
indicated
by
the
commenters.
It
should
be
noted
that
we
will
be
using
standard
body
weights
(
e.
g.,
70
kg
for
adults)
will
result
in
slightly
higher
PDRs.

29.
U.
S.
Borax
Inc.;
BioLab,
Inc.;
Nisus
Corporation;
Comment:
The
commenters
note
that
other
registered
products
having
lower
percentages
of
Boron
and
recommendations
for
lower
application
rates
were
not
show
in
the
TRED.
They
assert
that
those
shown
represent
the
highest
potential
for
incidental
oral
ingestion
from
swimming
pool
uses.

Agency
Response:
The
source
document
for
the
Boric
Acid
TRED
was
(
Exposure
and
Risk
Assessment
on
Lower
Risk
Pesticide
Chemicals
­
Boric
Acid
and
its
Sodium
Salts)
originally
meant
to
be
a
screening
level
assessment
focusing
on
products
having
higher
rates
of
exposure.
Conceptually,
if
estimates
of
exposure
from
high
application
rates
were
determined
to
be
of
no
or
low
concern,
logic
would
suggest
that
exposure
estimates
for
the
lower
rates
would
also
be
of
no
or
low
concern.
Inert
uses
were
estimated
to
be
one
percent
of
the
high
percentage
active
ingredient
uses.
The
inert
uses
showed
exposures
of
no
or
low
concern.
Since
exposures
of
concern
have
been
identified
for
products
having
high
application
rates,
lower
application
rates
will
also
be
evaluated.

30.
McIntyre
Associates,
Inc.
Comment:
Data
exist
in
Agency
files
that
would
allow
the
amount
of
surface
residues
from
the
pressure
treated
borate
systems
to
be
approximated
by
consideration
of
the
amount
of
residues
from
an
analogous
system.
For
example,
wood
pressure
treated
with
CCA
would
be
considered
analogous
to
wood
pressure
treated
with
DOT­
both
preservative
formulations
would
be
deeply
impregnated
into
the
wood
and
the
actual
surfaces
would
not
have
a
significantly
higher
concentration
of
chemicals.
In
a
review1
of
wipe
tests,
data
from
348
wipe
samples
from
wood
treated
to
a
0.40
pcf
retention
material
with
CCA
had
a
mean
value
of
0.356
µ
g/
cm2
of
chrome.
This
is
331
µ
g
per
square
foot.

The
amount
of
elemental
chrome
in
0.40
pounds
of
CCA
is
0.099
pounds
while
the
amount
of
elemental
boron
in
28
pounds
of
B2O3
is
0.087
pounds.
Thus,
one
would
expect
that
the
amount
of
surface
residue
from
wood
pressure
treated
with
borates
would
also
be
around
300
µ
g
per
square
foot.

As
shown,
the
approximate
amount
of
surface
residue
expected
based
on
analogous
science
(
300
µ
g/
sf)
is
very
small
compared
to
the
462,470
µ
g/
sf
calculated
by
the
topically
applied
route.
In
fact,
it
is
0.065%
and
a
corresponding
reduction
in
the
ADD
results
in
a
MOE
of
over
20,000.
This
is
well
beyond
the
MOE
of
100
required
for
residential
exposure.
Page
20
of
20
It
should
be
noted
that
the
surface
residue
data
came
from
an
Agency
report
and
that
the
values
chosen
were
the
highest
surface
residues
in
that
report.
The
data
came
from
unsealed
material
and
other
data
showed
that
various
coatings
significantly
reduced
the
surface
residues.
Therefore,
it
seems
reasonable
to
believe
that
this
analogous
method
would
represent
a
worst
case
scenario.

Agency
Response:
The
exposure
scenarios
for
wood
treatment
products
were
not
identified
until
late
in
the
TRED
process.
We
agree
to
evaluate
both
pressure
and
in
situ
wood
treatment
uses
in
the
revision.

In
general,
HED
prefers
chemical
specific
data
The
Antimicrobials
Division
was
responsible
for
the
CCA
treated
wood
assessment
and
HED
will
defer
to
that
division
whether
the
wipe
data
for
CCA.
They
do
not
rely
on
the
CCA
data
for
use
(
generically)
for
other
wood
treatment
chemicals.
We
note
that
other
commenters
including
Dr.
McIntyre
suggest
the
Agency
rely
on
boron
levels
in
surface
wafers
cut
from
treated
boards
that
were
presented
in
several
other
TRED
comment
packages.
The
Agency
agrees
to
consider
these
surface
wafer
data.

31.
Nisus
Corporation
Comment:
Nisus
suggests
a
review
of
available
data
and
draws
the
Agency's
attention
to
Study
Title:
Evaluation
of
Human
Exposure
Potential
of
Boric
Acid
Carpet
Treatment
for
Fleas
(
48
p.)
DPR
Study
ID
Number:
143425
Laboratory:
University
of
California,
Riverside
Dept.
of
Entomology
Report
Date:
11/
01/
1995
Received
at
DPR:
12/
27/
1995.
They
suggest
that
a
risk
assessment
on
this
type
of
application
would
be
similar
for
wood
treatments.
They
assert
that
although
reviewers
are
seeking
data
to
support
the
safety
of
each
application,
it
is
important
that
safe
methods
(
such
as
using
Boric
Acid
products)
are
not
eliminated
based
on
assumptions
of
misuse
and
where
modified
labeling
provides
reduced
exposure.

Agency
Response:
The
Agency
is
in
contact
with
the
California
Department
of
Pesticide
Regulation
(
DPR)
regarding
the
above
referenced
assessment.
According
to
DPR,
the
study
is
proprietary.
However,
we
note
that
the
assessment
is
likely
to
be
based
on
similar
study
design
as
the
draft
study
referenced
in
the
TRED
 
Human
Disodium
Octaborate
Tehrahydrate
Exposure
Following
Carpet
Flea
Treatment
is
Not
Associated
with
Significant
Dermal
Absorption.
At
the
time
the
TRED
was
being
prepared,
a
draft
of
the
study
was
in
our
possession.
Recently,
one
of
the
authors
has
provided
a
copy
of
the
study
as
presented
in
the
Journal
of
Exposure
Analysis
and
Environmental
Epidemiology,
Vol.
6,
No.
3,
1996.
In
the
study
report
are
discussions
of
the
transfer
of
DOT
residues.
These
kinds
of
measurements
are
useful
for
dermal
exposure;
however
for
non­
dietary
ingestion
assessments,
these
types
of
data
require
adjustment
for
the
increased
transfer
efficiency
due
to
wet
hands.
In
addition,
the
study
does
not
address
the
powder/
dust
formulations.
The
Agency
is
confident
this
data­
gap
will
be
easily
fulfilled.
