1
July
31,
2003
SIGNIFICANT
NEW
ALTERNATIVES
POLICY
PROGRAM
FIRE
EXTINGUISHING
AND
EXPLOSION
PREVENTION
SECTOR
RISK
SCREEN
ON
NAF
S
125
AS
A
SUBSTITUTE
FOR
HALON
1301
TOTAL
FLOODING
FIRE
EXTINGUISHERS
OCCUPIED
SPACES
This
risk
screen
contains
no
Clean
Air
Act
(
CAA)
Confidential
Business
Information
(
CBI)
and,
therefore,
can
be
disclosed
to
the
public.

1.
INTRODUCTION
Ozone­
depleting
substances
(
ODS)
are
being
phased
out
of
production
in
response
to
a
series
of
diplomatic
and
legislative
efforts
that
have
taken
place
over
the
past
few
years,
including
the
Montreal
Protocol
and
the
Clean
Air
Act
Amendments
of
1990
(
CAAA).
The
U.
S.
Environmental
Protection
Agency
(
EPA),
as
authorized
by
Section
612
of
the
CAAA,
is
developing
a
program
to
evaluate
the
human
health
and
environmental
risks
posed
by
alternatives
to
ODS.
The
main
purpose
of
EPA's
program,
called
the
Significant
New
Alternatives
Policy
(
SNAP)
program,
is
to
identify
acceptable
and
unacceptable
substitutes
for
ODS
in
specific
end
uses.
The
results
of
EPA's
screening
assessment
of
potential
human
health
and
environmental
risks
posed
by
substitutes
for
halon
fire
extinguishers
are
presented
in
the
Background
Document,
"
Risk
Screen
on
the
Use
of
Substitutes
for
Class
I
Ozone­
depleting
Substances:
Fire
Extinguishing
and
Protection
(
Halon
Substitutes)"
(
EPA
1994).
This
document
is
available
in
the
EPA's
docket.

EPA's
risk
screen
on
the
use
of
HFC­
125
with
0.15%
d­
limonene
(
NAF
S
125),
a
liquefied
gas
to
replace
halon
1301
as
a
total
flooding
agent
in
occupied
spaces,
is
summarized
in
this
document.
NAF
S
125
is
comprised
of
HFC­
125
and
(+)­
4­
isopropenyl­
1­
methylcyclohexene
(
d­
limonene)(
see
Table
1).
The
reader
is
referred
to
the
Background
Document
for
detailed
risk
screen
results
for
HFC­
125
and
the
methodologies
and
assumptions
used
to
conduct
the
risk
screen.
Because
HFC­
125
has
previously
been
listed
as
acceptable
by
SNAP
for
use
as
a
substitute
for
halon
1301
in
total
flooding
applications,
this
risk
screen
focuses
on
the
additive
dlimonene

Section
2
of
this
report
summarizes
the
results
of
the
risk
screen
for
d­
limonene.
Section
3
presents
atmospheric
modeling
and
potential
environmental
risks;
Section
4
discusses
2
July
31,
2003
occupational
exposure
at
manufacture;
Section
5
presents
exposure
at
the
end
use;
and
Section
6
assesses
risks
associated
with
general
population
exposure.

Table
1.
Composition
of
NAF
S
125
Constituent
Chemical
Formula
CAS
No.
Percent
of
Total
(
by
weight)

HFC­
125
(
pentafluoroethane)
CF3CHF2
354­
33­
6
99.85
±
0.1
(+)­
4­
isopropenyl­
1­
methylcyclohexene
(
d­
limonene)
C10H16
5989­
27­
5
0.15
±
0.05
2.
SUMMARY
OF
RESULTS
Use
of
NAF
S
125
as
a
total
flooding
agent
in
occupied
spaces
is
not
expected
to
pose
a
threat
to
atmospheric
integrity
or
human
health
as
long
as
NAF
S
125
extinguishers
are
only
used
by
specially
trained
and
selected
individuals.
It
is
also
recommended
that
NAF
S
125
only
be
used
in
industrial
and
commercial
application
and
in
accordance
with
the
safety
guidelines
in
the
latest
edition
of
the
NFPA
2001
Standard
for
Clean
Agent
Fire
Extinguishing
Systems.
In
addition,
it
is
suggested
that
potential
hazards
associated
with
the
use
of
NAF
S
125,
as
well
as
handling
procedures
to
reduce
risk
resulting
from
these
hazards,
be
clearly
labeled
on
each
NAF
S
125
extinguisher.

3.
ATMOSPHERIC
MODELING
This
section
presents
an
assessment
of
the
potential
risks
to
atmospheric
integrity
posed
by
the
use
of
NAF
S
125
as
a
flooding
agent.
The
ozone
depletion
potential
(
ODP),
global
warming
potential
(
GWP),
and
atmospheric
lifetime
of
the
substitutes
are
presented
in
Table
2.
The
environmental
impacts
resulting
from
use
of
NAF
S
125
are
generally
in
the
range
of
those
predicted
for
other
substitutes
examined
in
the
Background
document.
The
substitute
is
less
harmful
than
the
continued
use
of
Halon
1301.
3
July
31,
2003
Table
2.
ODPs,
GWPs,
and
Atmospheric
Lifetimes
of
the
Constituents
of
NAF
S
125
GWP
(
relative
to
CO2)

Constituent
ODP
100
Year
500
Year
ALT
HFC­
125
0
2,800
920
32.6
years
(+)­
4­
isopropenyl­
1­
methylcyclohexene
0
10
<
10
10
days
Source:
IPCC
(
1994,
1995),
The
UNEP
Ozone
Secretariat
Webpage
(
2000),
and
ICF
estimates.

4.
OCCUPATIONAL
EXPOSURE
AT
MANUFACTURE
The
estimated
workplace
environmental
exposure
limit
(
WEEL)
for
HFC
125
is
1000
ppm
averaged
over
an
8­
hour
time
period
(
8­
hour
TWA)
(
AIHA
1999).
The
AIHA
has
published
an
8­
hour
TWA
for
d­
limonene
of
30
ppm.
Therefore,
exposure
levels
for
HFC­
125
and
dlimonene
should
be
kept
below
1000
ppm
and
30
ppm,
respectively,
on
an
8­
hour
TWA
basis.
Additionally,
the
exposure
levels
should
be
kept
as
low
as
possible.

Based
on
the
manufacturer's
analysis,
EPA
recommends
the
following
for
establishments
installing
and
maintaining
total
flooding
systems:
°
adequate
ventilation
should
be
in
place
and
SCUBA
equipment
should
be
available
if
ventilation
is
suspected
to
be
inadequate;
and
°
proper
personal
protection
equipment
must
be
worn
(
impervious
butyl
gloves,
eye
protection,
chemical
resistant
aprons,
long
sleeves,
and
safety
shoes);
and
°
all
spills
should
be
cleaned
up
immediately
in
accordance
with
good
industrial
hygiene
practices;
and
°
training
for
safe
handling
procedures
should
be
provided
to
all
employees
that
would
be
likely
to
handle
the
containers
of
NAF
S
125
or
extinguishing
units
filled
with
the
material.
4
July
31,
2003
5.
EXPOSURE
AT
THE
END
USE
Total
Flooding
Applications
For
total
flooding
systems,
the
magnitude
of
exposure
to
the
halon
substitute
at
the
end
use
depends
on
the
design
concentration
of
the
flooding
agent
and
the
length
of
time
that
a
person
must
take
to
evacuate
the
area
in
which
the
agent
is
released.
Because
total
flooding
systems
are
designed
to
achieve
a
uniform
concentration
of
agent
within
a
space,
the
magnitude
of
exposure
is
independent
of
the
size
of
the
space,
size
of
the
fire,
or
proximity
of
the
worker
to
the
fire.
For
these
reasons,
the
analysis
of
potential
end
use
exposures
to
alternative
total
flooding
agents
is
straightforward;
it
considers
only
the
design
concentration
of
the
extinguishing
agent
and
standards
developed
to
limit
exposure
of
personnel
to
total
flooding
agents.

With
respect
to
exposures
incurred
after
the
discharge
of
an
installed
NAF
S
125
total
flooding
system,
the
specified
design
concentration
generally
ranges
from
between
9
percent
by
volume
(
90,000
ppm
total;
89,865
ppm
HFC­
125;
135
ppm
d­
limonene)
and
worst­
case
maximum
concentration
of
11.3
percent
by
volume
(
113,000
ppm
total;
112,830.5
ppm
HFC­
125;
169.5
ppm
d­
limonene).

To
assess
the
exposure
and
toxicity
concerns
associated
with
the
proposed
substitute,
the
magnitude
of
the
exposure
of
HFC­
125
is
compared
to
the
agent's
cardiotoxic
NOAEL.
The
cardiotoxic
NOAEL
for
HFC­
125
is
75,000
ppm
(
Calm
1996).
HFC­
125'
s
design
concentration
of
89,865
 
112,830
ppm
exceeds
the
NOAEL.
However,
results
calculated
using
the
Physiologically
Based
Pharmacokinetic
(
PBPK)
model,
presented
in
Table
3,
indicate
that
design
concentrations
less
than
or
equal
to
11.5
percent
by
volume
are
safe
for
5
minute
exposures
in
occupied
spaces
(
NFPA
2001).
Therefore,
the
proposed
concentration
of
HFC­
125,
which
is
less
than
11.5%
by
volume,
should
not
pose
a
risk
to
human
health
in
the
event
of
an
accidental
release
(
in
the
absence
of
a
fire).

To
further
assess
the
toxicity
concerns
associated
with
NAF
S
125,
the
magnitude
of
exposure
to
d­
limonene
was
compared
to
the
amount
of
d­
limonene
to
which
a
person
could
safely
be
exposed
in
the
5
minutes
following
an
accidental
release.
This
comparison
indicates
that
the
amount
of
d­
limonene
in
the
NAF
S
125
design
concentration
should
not
cause
adverse
effects
following
a
5­
minute
exposure
(
Falk­
Filipsson
et
al.
1993)
(
See
Attachment
1).

Upon
combustion,
the
synergistic
effect
of
NAF
S
125
can
result
in
the
formulation
of
hydrochloric
and
other
acids
at
levels
potentially
harmful
to
human
life
and
health.
The
second
constituent
of
NAF
S
125,
(+)­
4­
isopropenyl­
1­
methylcyclohexene
(
d­
limonene),
is
intended
to
5
July
31,
2003
detoxify
this
mixture.
Testing
performed
on
other
chemically
similar
mixtures
indicates
that
detoxification
is
likely
(
NAFG,
1991),
but
it
has
not
been
proven
that
(+)­
4­
isopropenyl­
1­
methylcyclohexene
will
detoxify
NAF
S
125.
Therefore,
use
of
NAF
S
125
as
a
flooding
agent
in
normally
occupied
spaces
may
pose
risks
to
human
health.

OSHA
regulations
indicate
that
levels
of
oxygen
below
19.5
percent
in
confined
spaces
create
an
oxygen­
deficient
atmosphere
for
workers.
Manufacturers
of
NAF
S
125
will
therefore
need
to
ensure
that
discharges
of
the
agent
within
an
enclosed
space
do
not
result
in
oxygen
concentrations
that
are
below
this
value
(
U.
S.
Department
of
Labor
OSHA
Respiratory
Protection
59:
58884­
58956,
1994).

Use
conditions
for
total
flooding
applications
are
governed
by
other
organizations
including
NFPA,
Underwriters
Laboratories,
and
OSHA.
Use
of
the
SNAP­
approved
chemical
discussed
in
this
risk
screen
is
subject
to
the
requirements
of
these
organizations.

Table
3.
Physiologically
Based
Pharmacokinetic
model
(
PBPK)
Results
for
Safe
Human
Exposure
Times
to
Concentrations
of
HFC­
125
HFC­
125
Concentration
%
v/
v
ppm
Human
Exposure
Time
(
minutes)
7.5
75,000
5.00
8.0
80,000
5.00
8.5
85,000
5.00
9.0
90,000
5.00
9.5
95,000
5.00
10.0
10,000
5.00
10.5
105,000
5.00
11.0
110,000
5.00
11.5
115,000
5.00
12.0
120,000
1.67
12.5
125,000
0.59
13.0
130,000
0.54
13.5
135,000
0.49
This
table
is
copied
from
NFPA
(
2001),
Table
1­
6.1.2.1(
b).
6
July
31,
2003
6.
GENERAL
POPULATION
EXPOSURE
A.
AMBIENT
AIR
The
assessment
presented
in
the
Background
Document
of
general
population
exposure
to
HFC­
125
through
processing
and
use
as
a
total
flooding
agent
shows
that
it
is
not
expected
to
cause
any
significant
threats
to
human
health.
The
quantity
of
HFC­
125
released
to
ambient
air
through
processing
and
use
of
NAF
S
125
will
be
considerably
less
than
that
released
through
processing
and
use
of
HFC­
125
as
a
total
flooding
agent.
Therefore,
it
can
be
concluded
that
the
general
population
exposure
to
HFC­
125
due
to
the
processing
and
use
of
NAF
S
125
is
not
expected
to
cause
any
significant
threats
to
human
health.
D­
limonene
is
widely
used
as
a
solvent
in
cleaning
solutions
and
has
a
variety
of
other
uses.
The
atmosphere
is
expected
to
be
the
predominant
environmental
sink
of
d­
limonene
due
to
its
high
volatility.
Measured
concentrations
(
between
1979­
1992)
of
limonene
in
the
air
range
from
0.6­
1.1

g/
m3
(
rural
areas),
0.6­
11.1

g/
m3
(
suburban/
urban),
and
1.7­
240

g/
m3
(
industrial/
waste
sites)
(
IPCS
1988).
Given
that
d­
limonene
exists
at
higher
percentages
in
commonly
used
cleaners,
removers,
and
polishes
than
it
does
in
NAF
S
125,
the
effects
of
d­
limonene
containing
fire­
extinguishers
on
the
general
population
are
expected
to
be
minimal.

B.
SURFACE
WATER
As
discussed
in
the
Background
Document,
the
physiochemical
properties
of
the
majority
of
halon
substitutes
make
it
unlikely
that
the
substitutes
would
be
released
to
surface
water
as
a
result
of
use.
In
the
case
of
NAF
S
125,
all
of
the
constituents
would
rapidly
vaporize
during
expulsion
from
the
container
and
therefore
could
not
settle
and
cause
surface
water
contamination.
D­
limonene
has
a
low
solubility
in
water
and
high
volatility.
Release
into
aqueous
systems
would
result
in
volatilization
of
d­
limonene
from
surface
water.

C.
SOLID
WASTE
As
discussed
above,
HFC­
125
and
d­
limonene
will
vaporize
upon
discharge.
Therefore,
use
of
this
agent
will
not
generate
solid
waste.
7
July
31,
2003
REFERENCES
American
Industrial
Hygiene
Association.
The
AIHA
1999
Emergency
Response
Planning
Guidelines
and
Workplace
Environmental
Exposure
Level
Guides
Handbook.
American
Industrial
Hygiene
Association.
Fairfax,
VA
1999.

Calm,
James
M.
1996.
The
Toxicity
of
Refrigerants.
Presented
at
the
International
Refrigeration
Conference,
Purdue
University,
July
1996.

EPA
1994.
Significant
New
Alternatives
Policy
Technical
Background
Document:
Risk
Screen
on
the
Use
of
Substitutes
for
Class
I
Ozone­
depleting
Substances:
Refrigeration
and
Air
Conditioning.
Stratospheric
Protection
Division.
March,
1994.

Falk­
Filipsson,
A.,
Lof,
A.,
Hagberg,
M,
Hjelm,
EW,
and
Wang,
Z.
1993.
d­
Limonene
exposure
to
humans
by
inhalation:
uptake,
distribution,
elimination,
and
effects
on
the
pulmonary
function.
J
Toxicol
Environ
Health.
38:
77­
88.

ICF,
2000.
Risk
Screen
for
NAF
P­
IV
Fire
Extinguisher
(
Final).
March,
2000.

IPCC,
1994.
Climate
Change
1994:
The
Science
of
Climate
Change.
Intergovernmental
Panel
on
Climate
Change.
Cambridge
University
Press.

IPCC,
1995.
Climate
Change
1995:
The
Science
of
Climate
Change.
Intergovernmental
Panel
on
Climate
Change.
Cambridge
University
Press.

IPCS,
1998.
Concise
International
Chemical
Assessment
Document
No.
5:
Limonene.
World
Health
Organization,
Geneva.

NFPA,
2001.
Standards
for
Clean
Agent
Fire
Extinguishing
Systems
2000
Edition.
The
Technical
Committee
on
Halon
Alternative
Protection
Options.
February
2000.
p
14.

U.
S.
Department
of
Labor
1994.
Occupational
Health
and
Safety
Administration.
Respiratory
Protection
 
59:
58884­
58956.
http://
www.
osha.
gov/
pls/
oshaweb/
owadisp.
show_
document?
p_
table=
FEDERAL_
REGISTER&
p_
id=
13426&
p_
text_
version=
FALSE.

The
UNEP
Ozone
Secretariat
Webpage.
2000.
"
Amendment
to
the
Montreal
Protocol
on
Substances
that
Deplete
the
Ozone
Layer."
http://
www.
unep.
org/
ozone/
Copenhagen­
Amendment.
htm.
Accessed
3/
14/
00.
