Agency
Response
to
Public
Comments
Submitted
to
the
E­
Docket
on
the
PHMB
Preliminary
Risk
Assessment
November
22,
2005
Case
3122
PC
Code
111801
Office
of
Pesticide
Programs
Antimicrobials
Division
U.
S.
Environmental
Protection
Agency
1200
Pennsylvania
Avenue,
NW
Washington,
DC
20460
Page
2
of
4
On
September
10,
2004,
the
preliminary
risk
assessment
(
PRA)
for
poly(
hexamethylenebiguanide)
hydrochloride
(
PHMB)
was
posted
on
the
EPA's
E­
Docket
for
public
comments
(
Phase
3
of
the
reregistration
process).
From
September
14­
24,
2004,
comments
were
submitted
to
the
docket
in
response
to
the
PHMB
PRA
and
supporting
documents.
The
Antimicrobials
Division
has
prepared
this
document
to
respond
to
these
comments.
In
response
to
comments
submitted
for
EPA
Docket
OPP­
2004­
0305,
the
Agency
believes
that
the
following
adequately
addresses
the
issues
raised
by
the
public.
All
comments
can
be
found
on
the
EPA
Docket
at
http://
www.
epa.
gov/
edocket.

Issue
#
1
In
response
to
comment
OPP­
2004­
0305­
0014
(
submitted
by
a
private
citizen)
and
the
response
submitted
by
the
registrant,
Arch
Chemicals,
Inc
(
OPP­
2004­
0305­
0020)
regarding
the
efficacy
of
PHMB
as
a
swimming
pool
disinfectant:

As
a
part
of
the
reregistration
process,
the
final
RED
document
issues
a
Product­
Specific
Data
Call­
In,
which
includes
efficacy
data
for
the
public
health
products,
such
as
swimming
pool
sanitizers.

Issue
#
2
In
response
to
the
second
comment
submitted
by
Arch
Chemicals,
Inc
(
OPP­
2004­
0305­
0021):

All
of
the
comments,
including
those
on
the
Agency's
authority
to
conduct
a
dietary
risk
assessment
for
PHMB
are
addressed
in
the
Response
to
Error
Corrections
document
and
the
response
to
comments
document
(
dated
9/
24/
04)
on
the
HIARC
Report.

Issue
#
3
In
response
to
all
comments
regarding
an
extension
of
the
comment
period:

The
abbreviated
comment
period
for
the
PRA
and
science
chapters
on
the
EDocket
was
utilized
to
meet
the
Agency's
deadline
of
completing
the
Reregistration
Eligibility
Decision
in
FY
`
04
to
meet
our
commitments
to
stakeholders.
In
keeping
with
EPA's
policy
of
maintaining
a
transparent
process,
the
PRA
is
available
on
EDocket
and
is
posted
on
the
web
site
http://
www.
epa.
gov/
pesticides/
antimicrobials.
All
comments
were
considered
(
those
received
in
a
reasonable
time
period
after
the
closing
date
were
considered
in
any
decision
memorandum).

Issue
#
4
The
California
Regional
Water
Quality
Control
Board
of
the
San
Francisco
Bay
Area,
the
Sanitation
Districts
of
Los
Angeles
County,
the
California
Stormwater
Quality
Association,
and
the
City
and
County
of
San
Francisco
Department
of
the
Environment
raised
five
main
issues
about
the
PRA
on
PHMB
in
comments
dated
September
23
through
27,
2004.
In
response
to
these
comments
regarding
the
lack
of
an
ecological
assessment
for
swimming
pool
chemicals
and
household
disinfectants
with
the
potential
for
"
down
the
drain"
exposure:
Page
3
of
4
1.
Surface
water
releases
and
environmental
exposure:

For
certain
use
categories,
such
as
indoor
sanitizers
or
contained
outdoor
uses,
such
as
swimming
pools,
the
environmental
exposure
will
be
limited
in
most
cases,
due
either
to
treatment
of
wastewaters
discharged
through
municipal
sewers1
and/
or
Federal
or
Local
restrictions
on
how
wastewaters
are
to
be
handled.
For
such
uses,
environmental
modeling
is
not
currently
performed,
and
only
a
minimal
toxicity
data
set
is
required
(
Overview
of
the
Ecological
Risk
Assessment
Process
in
the
Office
of
Pesticide
Programs
U.
S.
Environmental
Protection
Agency
­
Endangered
and
Threatened
Species
Effects
Determinations,
1/
23/
04,
Appendix
A,
Section
IIB,
pg.
81).
Chemicals
in
these
categories,
therefore,
do
not
currently
undergo
a
full
screening­
level
risk
assessment
and
are
considered
to
fall
under
a
"
no
effect"
determination.
The
indoor
uses
of
PHMB,
as
well
as
the
swimming
pool
use,
fall
into
this
category.

While
AD
recognizes
that
the
swimming
pool
and
oil
recovery
uses
of
PHMB
occur
outdoors,
they
are
contained
uses,
and
any
spent
drilling
muds,
pool
water,
or
other
pesticide­
containing
waste
is
required
to
be
disposed
of
properly,
in
accordance
with
product
label
requirements
and
other
Federal,
State
and
Local
laws.
While
dumping
of
treated
wastes
into
storm
sewers,
into
surrounding
waters,
or
onto
the
ground
could
occur,
this
would
be
considered
a
misuse
of
the
pesticide.
Illegal
uses,
or
"
misuses,"
of
pesticides
are
not
considered
in
Office
of
Pesticide
Program
risk
assessments;
the
assessments
are
based
on
the
correct,
labeled
use
of
the
pesticide
products.

2.
Required
Environmental
Fate
and
Aquatic
Toxicity
Data
As
stated
in
the
40CFR
§
158,
the
Agency
requires
a
standard
set
of
environmental
fate
and
aquatic
toxicity
studies
to
be
submitted
for
indoor
uses,
including
hydrolysis,
acute
avian
oral
toxicity,
acute
freshwater
fish
toxicity,
and
acute
freshwater
invertebrate
toxicity.
These
data
requirements
have
been
fulfilled
for
PHMB,
and
the
database
is
considered
adequate
for
the
purposes
of
this
risk
assessment.

3
Municipal
waste
water
treatment
and
compliance
with
NDPES
permit
requirements
and
meeting
Clean
Water
Act
standards.

Many
of
the
uses
of
PHMB
occur
indoors
(
e.
g.,
hard
surface
sanitizer,
cut
flower
preservative),
resulting
in
PHMB
residues
being
discharged
into
municipal
waste
water
via
household
drains.
AD
recognizes
the
possibility
of
some
of
these
pesticides
entering
into
US
waterways,
which
may
pose
exposure
and
hazard
concerns.
We
are
in
the
process
of
developing
and
validating
various
modeling
programs,
which
will
help
us
to
ascertain
that
pesticides
entering
into
U.
S.
water
ways,
as
well
as
into
the
municipal
waste
treatment
plants,
are
not
at
levels
of
concern.

AD
also
searched
the
NRML
Treatability
Database
for
PHMB
(
US
EPA/
ORD/
NRML),
but
no
information
on
the
efficiency
of
wastewater
treatment
removal
technologies
for
PHMB
was
found.
We
will
continue
to
consult
the
database
for
future
assessments
on
indoor­
use
pesticides;

1
The
EPA/
ORD/
NRML
Treatability
Database
is
consulted
for
such
chemicals,
in
order
to
determine
the
effectiveness
of
wastewater
treatment
removal
technologies
for
the
chemical
in
question.
If
information
on
the
chemical
is
not
available
in
the
database,
predictive
modeling
(
EPIWIN)
is
conducted,
where
possible.
Page
4
of
4
however,
the
database
is
several
years
old,
and
no
update
of
the
information
within
the
database
is
planned
by
NRML.
Predictive
modeling
(
EPISUITE/
EPIWIN,
US
EPA)
could
not
be
performed
for
PHMB
as
it
is
a
polymeric
molecule
(
guanidine
sitting
in
a
matrix).
Predictive
modeling
programs,
such
as
EPISUITE
do
not
have
any
estimations
for
polymers.

AD
is
in
the
process
of
developing
and
validating
screening­
level
models
to
estimate
environmental
concentrations
from
indoor
pesticide
uses.
When
this
methodology
has
been
developed
and
validated,
we
will
consider
adding
the
screening 
level
modeling
to
our
indoor­
use
assessments.

4.
Swimming
Pool
and
Spa
Uses
Require
Environmental
Risk
Assessments.

PHMB
is
registered
for
use
in
swimming
pools
and
spas.
While
pool
and
spa
owners
may,
in
fact,
discharge
waters
from
pools
and
spas
into
storm
sewers
or
municipal
sewer
systems,
this
activity
is
not
within
the
regulatory
authority
of
FIFRA.
We,
therefore,
do
not
assess
this
activity
in
our
risk
assessments
for
pesticides.
Note
also
that
illegal
uses,
or
"
misuses,"
of
pesticides
are
not
considered
in
Office
of
Pesticide
Program
risk
assessments;
the
assessments
are
based
on
the
correct,
labeled
use
of
the
pesticide
products.

5.
Clean
Water
Act
and
FIFRA
We
agree
that
all
Agency
programs:
OPP,
OPPT,
OW,
etc.
should
work
together
to
estimate
the
concentrations
of
all
chemicals
entering
into
our
environmental
media
(
air/
water/
soil).
To
this
end,
AD
is
working
on
adding
to
its
list
of
tools
some
additional
modeling
programs,
possibility
of
monitoring
programs.
