Page
1
of
6
­
1
­
Halohydantoins
Case
Overview
Reregistration
Case
Number
3055
A.
Chemical
Overview
This
Reregistration
Eligibility
Document
(
RED)
covers
a
group
of
active
ingredients
that
are
collectively
known
as
the
Dihalodialkylhydantoins
or
Halohydantoins.
The
following
active
ingredients
are
covered
by
the
RED.

Common
Name:
Dihalodialkylhydantoins
or
Halohydantoins
Chemical
Name
CAS#
MW
OPP
Chemical
Code
1­
Bromo­
3­
Chloro­
5,5­
16079­
88­
2
241.5
6315
Dimethylhydantoin
(
C5­
H6­
Br­
Cl­
N2­
O2)

BromoChloro­
5,5­
32718­
18­
6
241.5
6315
Dimethlyhydantoin
(
C5­
H6­
Br­
Cl­
N2­
O2)

1,3­
Dibromo­
5,5
77­
48­
5
286
6317
Dimethylhydantoin
(
C5­
H6­
Br2­
N2­
O2)

1,3­
Dichloro­
5,5­
118­
52­
5
197
28501
Dimethylhydantoin
(
C5­
H6­
Cl2­
N2­
O2)

1,3­
Dichloro­
5­
Ethyl­
89415­
87­
2
211
128826
5­
Methylhydantoin
(
C6­
H8­
Br­
Cl­
N2­
O2)

Basic
Manufacturers:
Albemarle
Corporation
Ameribrom,
Inc./
Dead
Sea
Bromine
Group
Bio­
Lab,
Inc./
Great
Lakes
Chemical
Corporation
Lonza
Inc.
Page
2
of
6
­
2
­
Chemical
Characterization
Structurally,
the
halohydantoins
consist
of
a
central
organic
hydantoin
ring
moiety
(
either
dimethylhydantoin
or
ethylmethylhydantoin)
to
which
halogen
atoms
(
bromine
and/
or
chlorine)
can
be
attached
at
both
the
1
and
3
positions
on
the
hydantoin
ring.

In
concentrated
form,
the
halohydantoins
are
very
stable.
Upon
usage,
which
involves
dilution
in
water
or
a
water
system,
the
halohydantoins
rapidly
decompose
to
release
chlorine
and/
or
bromine
and
dimethylhydantoin
(
DMH)
and,
for
certain
products,
ethylmethylhydantoin(
EMH).
These
released
halogens
react
with
water
to
form
either
hypochlorous
or
hypobromous
acid,
which
is
the
actual
biocidal
agent.
Accordingly,
the
halohydantoins
are
essentially
delivery
systems
for
hypochlorous
and
hypobromous
acid.

The
two
key
advantages
of
halohydantoins
over
inorganic
forms
of
chlorine
and
bromine
are
that
they
are
less
hazardous
to
handle
and
store
(
because
of
the
corrosive
nature
of
the
inorganic
forms
of
chlorine
and
bromine)
and
the
fact
that
the
bound
form
allows
for
a
slower
and
more
manageable
release
of
the
halogen
atoms
when
they
are
placed
in
water.
The
latter
characteristic
helps
to
maintain
a
more
consistent
halogen
level
in
the
water
source
where
they
are
added.

B.
Use
Profile
The
halohydantoins
are
used
for
microbial
control
in
water
and
water
systems.
In
particular,
the
halohydantoins
are
used
as
disinfectants
in
commercial
and
residential
swimming
pools,
spas
and
hot
tubs;
as
sanitizers
for
treatment
of
toilet
bowl
water
in
homes;
and
for
controlling
bacterial
and
fungal
contamination
in
a
variety
of
industrial
water
systems
such
as
industrial
cooling
water
systems,
pulp
and
paper
mill
process
water,
wastewater
treatment
systems,
air
washer
water
systems,
sewage
systems,
industrial
processing
water,
irrigation
systems,
and
ornamental
ponds.

The
only
food­
use
for
the
halohydantoins
is
as
a
slimicide
in
the
manufacture
of
food­
contact
paper
and
paperboard.
The
1998
Antimicrobial
Regulation
Technical
Corrections
Act
(
ARTCA)
gave
the
U.
S.
Food
and
Drug
Administration
(
FDA)
jurisdiction
for
regulating
dietary
residues
of
food­
contact
slimicides
under
Section
409
of
the
Federal
Food,
Drug
and
Cosmetic
Act
(
FFDCA).
In
addition,
EPA
is
responsible
for
registering
the
slimicide
product
under
FIFRA.
The
FDA
regulation
that
permits
the
halohydantoins
to
be
used
as
slimicides
in
the
manufacture
of
food­
contact
paper
and
paperboard
is
in
21
C.
F.
R.
Part
176.300.
Page
3
of
6
­
3
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SUPPORTED
USE
SITES:

Indoor
Food
No
use
sites
identified
Indoor
Non­
Food
Hydrostatic
Sterilizer
Water
Systems
Pasteurizer/
Warmer/
Cannery/
Retort
Water
Systems
Transportation
Cleaning
Indoor
Residential
Toilet
Bowls
and
Urinals
Bathroom
Premises/
Hard
Surfaces
Aquatic
Non­
Food
Residential
Swimming
Pool
Water
Systems
Air
Conditioner
Hot
Tubs
&
Spas.

Aquatic
Food
Pulp
and
Paper
Mill
Water
(
food
contact
paper)

Aquatic
Nonfood
Ornamental
Ponds/
Aquaria
Irrigation
Systems
Aquatic
Non­
Food
Industrial
Air
Washer
Water
Systems
(
includes
air
scrubbing
and
washing)
Evaporative
Condenser
Water
Systems
Pulp
and
Paper
Mill
Systems
Sewage/
Wastewater
Treatment
Systems
Commercial/
Industrial
Water
Cooling
Tower
Systems
Heat
Exchanger
Water
Systems
Industrial
Processing
Water
Photo
Processing
Water
Secondary
Oil
Recovery
Injection
Water
Oil
Recovery
Drilling
Muds
And
Packer
Fluids
Recirculating
Cooling
Water
(
Greenhouses
&
Nurseries)
Page
4
of
6
­
4
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APPLICATION
RATES:
Indoor
Non­
Food
For
recirculating
cooling
water
systems
the
typical
rate
of
application
ranges
from
0.1
to
0.75
lbs
per
1,000
gallons
of
water
with
5­
70
ppm
Halohydantoins
with
0.5
­
5
ppm
Halogen
by
method
of
PLS,
PS
feeders,
PL
and
PU.
End
Use
pack
size
ranges
from
25
to
2,200
lb.
for
briquettes,
tablets
and
in
granular
form.
The
end
use
pack
size
for
gels
range
from
22
oz
to
400
pounds.

For
transportation
cleaning,
1
to
5
ppm
of
Halohydantoins
with
1
to
3
ppm
Halogen
is
used
at
a
typical
rate
of
.025
to
0.1
lbs
per
1,000
gallons
of
water.
PLS
or
PS
feeder
is
used
for
Briquettes
and
tablets
in
end
use
pack
sizes
that
range
from
20
to
50
pounds.

Indoor
Residential
For
toilet
bowls
and
urinals,
1
to
5
ppm
of
Halohydantoins
with
2
to
10
ppm
of
Halogen
is
used
by
method
of
PLS
at
a
typical
rate
of
17
to
25
grams
per
month
in
briquettes
and
tablet
form.

For
bathroom
premises
and
hard
surfaces,
588
ppm
of
Halohydantoins
with
1,125
ppm
of
Halogen
is
used
at
a
typical
rate
of
0.45
ounces
per
every
3
gallons
of
water
applied
by
method
of
mop,
BR,
and
W.
Product
is
in
granular
and
tablet
form
in
end
use
pack
sizes
ranging
from
1
to
50
pounds.

Aquatic
Non­
food
Residential
For
residential
and
commercial
pools,
50
to
300
ppm
of
Halohydantoins
with
1
to
4
ppm
of
Halogen
is
used
at
a
weekly
rate
of
0.5
to
2.5
pounds
per
10,000
gallons
of
water.
Product
is
dispensed
through
a
PLS/
PS
feeder
in
tablet,
briquettes
and
granular
form
from
end
use
packs
sizes
that
range
from
20
to
50
pounds.

For
residential
and
commercial
spas,
30
to
100
ppm
of
Halohydantoins
with
2
to
6
ppm
of
Halogen
is
used
at
a
weekly
rate
of
0.1
to
0.5
pounds
per
1,000
gallons
of
water.
Product
is
dispensed
through
a
PLS/
PS
feeder
in
tablet,
briquettes
and
granular
form
from
end
use
packs
sizes
that
range
from
1
to
50
pounds.

For
use
in
air
conditioner
and
dehumidifier
basin/
drip
pans,
one
ore
more
20
gram
tablets
are
placed
in
the
basin
or
drip
pan
from
end
use
pack
sizes
are
in
25
and
50
pounds.

Aquatic
Food
For
Pulp
&
Paper
w/
food
contact,
5
to
25
ppm
of
Halohydantoins
with
1
to
5
ppm
of
Halogen
is
used
at
a
typical
rate
of
0.16
to
2.0
pounds
per
ton
of
paper.
A
PLS/
PS
feeder
Page
5
of
6
­
5
­
or
PU
is
used
to
dispense
product
in
briquette,
granular,
powder,
tablet
and
gel
form.
End
Use
pack
size
ranges
from
25
to
2,200
lb.
for
briquettes,
tablets
and
in
granular
form.
The
end
use
pack
size
for
gels
range
from
22
oz
to
400
pounds.

Aquatic
Non­
Food
For
Decorative
Waters
without
fish,
50
to
260
ppm
of
Halohydantoins
with
1
to
3
ppm
of
Halogen
is
used
at
a
weekly
rate
of
0.5
to
1.4
pounds
per
10,000
gallons
of
water.
A
PLS/
PS
feeder
is
used
to
dispense
product
in
briquette,
granular,
tablet
and
gel
form.
End
use
pack
size
ranges
from
22oz
to
400
pounds
for
gel
and
20
to
50
pounds
for
all
other
forms.

For
irrigation
and
automatic
water
distribution
systems
(
not
for
use
on
food
crops)
8
to
24
ppm
of
Halohydantoins
with
5
to
15
ppm
of
Halogen
is
used
at
a
typical
rate
of
15
to
45
grams
per
1,000
gallons
of
water.
A
PLS/
PS
feeder,
PU,
or
PL
is
used
to
dispense
product
in
granular,
powder
and
tablet
form.
End
use
pack
sizes
are
in
3
and
25
pounds.

Aquatic
Non­
Food
Industrial
For
Recirculating
cooling
systems,
5
to
70
ppm
of
Halohydantoins
with
0.5
to
5
ppm
of
Halogens
used
at
a
typical
rate
of
0.1
to
0.75
pounds
per
1,000
gallons
of
water
dependent
on
level
of
biological
control.
A
PLS/
PS
feeder,
PU,
or
PL
is
used
to
dispense
product
in
granular,
briquettes,
tablet
and
gel
form.
End
use
pack
sizes
range
from
22
oz
to
400
pounds
for
gel
form
and
25
to
2,200
pounds
for
all
other
forms.

For
once
through
cooling
systems,
5
to
35
ppm
of
Halohydantoins
with
0.5
to
5
ppm
of
Halogen
is
used
at
a
typical
rate
of
0.1
to
0.3
pounds
per
1,000
gallons
of
water.
A
PLS/
PS
feeder,
PU,
or
PL
is
used
to
dispense
product
in
granular,
briquettes,
tablet
and
gel
form.
End
use
pack
sizes
range
from
22
oz
to
400
pounds
for
gel
form
and
25
to
2,200
pounds
for
all
other
forms
For
Pulp
and
Paper,
5
to
25
ppm
of
Halohydantoins
with
1
to
5
ppm
of
Halogen
is
used
at
a
typical
rate
of
0.16
to
2.0
pounds
per
ton
of
paper.
A
PLS/
PS
feeder
or
PU
is
used
to
dispense
product
in
granular,
powder,
tablet
and
gel
form.
End
use
pack
sizes
range
from
22
oz
to
400
pounds
for
gel
form
and
25
to
2,200
pounds
for
all
other
forms.

For
sewage
and
wastewater
treatment
systems,
5
to
35
ppm
of
Halohydantoins
with
0.5
to
5
ppm
of
Halogen
is
used
at
a
typical
rate
of
0.1
to
0.75
pounds
per
1,000
gallons
of
water.
A
PLS/
PS
feeder,
PU,
or
PL
is
used
to
dispense
product
in
briquette,
granular,
tablet
and
gel
form.
End
use
pack
sizes
range
from
22
oz
to
400
pounds
for
gel
form
and
25
to
2,200
pounds
for
all
other
forms.

For
photo
processing,
1
to
5
ppm
of
Halohydantoins
with
1
to
3
ppm
of
Halogen
is
used
at
a
typical
rate
of
0.006
to
0.02
pounds
per
1,000
gallon
of
water.
A
PLS/
PS
feeder
is
used
to
dispense
product
in
granular,
briquettes
and
tablet
form.
End
use
pack
sizes
range
from
1
to
50
pounds.
Page
6
of
6
­
6
­
For
secondary
oil
recovery
injection
water,
300
ppm
of
Halohydantoins
with
280
ppm
of
Halogen
is
used
at
a
typical
rate
of
2.3
pounds
per
1,000
gallons
of
water.
A
PLS/
PS
feeder
is
used
to
dispense
product
in
granular
and
tablet
form.
End
use
pack
sizes
range
from
25
to
2,200
pounds.

For
oil
recovery
drilling
muds&
Packer
Fluids,
940
ppm
of
Halohydantoins
with
1,800
ppm
of
Halogen
is
used
at
a
typical
rate
of
15
pounds
per
1,000
gallons
of
water.
A
PLS/
PS
feeder
is
used
to
dispense
product
in
granular
and
tablet
form.
End
use
pack
sizes
range
from
25
to
2,200
pounds
For
recirculating
cooling
water
for
greenhouses
and
nurseries,
8
to
24
ppm
of
Halohydantoins
with
5
to
15
ppm
of
Halogen
is
used
at
a
typical
rate
of
15
to
45
grams
per
1,000
gallons
of
water.
A
PLS/
PS
feeder
is
used
to
dispense
product
in
granular,
powder
and
tablet
form.
End
use
pack
sizes
are
in
3
and
25
pounds.

TARGET
PESTS:
Slime­
forming
bacteria
and
fungi;
human
pathogens
in
swimming
pools,
spas,
hot
tubs,
toilet
bowls
and
urinals;
mollusks
and
algae.

FORMULATION
TYPES:
Powder,
granular,
tablets
(
including
nuggets),
briquettes
and
gel.
Each
formulation
is
designed
to
best
serve
a
certain
type
of
application
with
the
product
form
influencing
the
dissolution
rate.

ACUTE
TOXICITY
AND
CHEMICAL
CLASS:

Halohydantoins
are
classified
as
moderately
toxic
after
acute
oral
administration.
They
are
markedly
irritating
to
lung
tissues
upon
inhalation
with
potential
systematic
absorption
and
tissue
damage.
On
contact
they
are
corrosive
to
peripheral
tissue
­
eyes,
skin
and
mucous
membrane.
Halohydantoins
are
toxic
to
aquatic
organisms.
They
are
considered
strong
oxidizing
agents.

C.
Regulatory
History
In
1987,
EPA
issued
a
Data
Call­
In
(
DCI)
for
antimicrobial
products,
which
covered
the
halohydantoins.
In
response
to
this
DCI,
generic
toxicology,
environmental
fate
and
ecotoxicity
data
were
submitted.
Generic
data
were
developed
on
the
breakdown
products,
dimethylhydantoin
(
DMH)
and
ethylmethylhydantoin
(
EMH).
The
primary
reason
for
developing
generic
data
on
DMH
and
EMH
is
that
these
ring
structures
represent
the
persistent
component
of
the
halohydantoins.
A
secondary
reason
for
evaluating
the
hydantoin
moieties
rather
than
the
entire
halohydantoin
molecule
is
that
the
corrosive
properties
of
the
released
halogens
would
limit
the
amount
of
chemical
that
could
be
administered
to
laboratory
animals;
thereby
precluding
a
meaningful
evaluation
of
the
hydantoin
moieties.
The
Agency
also
determined
that
data
developed
on
DMH
was
applicable
to
EMH
and
vice
versa.
The
basis
for
this
decision
was
the
similarity
of
the
chemical
structure
of
these
two
chemicals
and
the
similarity
of
results
from
studies
conducted
on
both
the
DMH
and
EMH
compounds.
