Document ID: EPA-HQ-OAR-2004-0022-0396
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2005-08-23T04:00Z

COMBUSTION
HUMAN
HEALTH
RISK
ASSESSMENT
FOR
DUPONT
DOW
ELASTOMERS,
L.
L.
C.
LAPLACE,
LOUISIANA
PREPARED
BY
US
EPA
REGION
6
CENTER
FOR
COMBUSTION
SCIENCE
AND
ENGINEERING
DALLAS,
TEXAS
JANUARY
5,
2001
TABLE
OF
CONTENTS
Foreword
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1
Executive
Summary
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2
Background
Information
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3
Facility
and
Source
Information
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4
Air
Modeling
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6
Compounds
of
Potential
Concern
(
COPCs)
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7
Exposure
Assessment
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9
Study
Area
Characterization
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9
Exposure
Scenario
Locations
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10
Transport
and
Fate
Parameters
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10
Risk
Characterization
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10
Excess
Cancer
Risks
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11
Non­
Carcinogenic
Health
Effects
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11
Other
Risks
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11
Uncertainty
Discussion
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12
Bio­
Transfer
Factors
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13
Use
of
Non­
Detected
Compounds
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13
Compounds
Dropped
from
Quantitative
Analysis
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14
Unidentified
Organic
Compounds
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14
Conclusion
&
Recommendations
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15
References
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17
List
of
Appendices
Appendix
A:
Air
Modeling
Appendix
B:
Spreadsheets
Appendix
C:
Mapping
Appendix
D:
Risk
Modeling
Appendix
E:
IRAP­
h
View
Project
Files
Page
1
of
17
FOREWORD
On
May
18,
1993,
the
United
States
Environmental
Protection
Agency
(
EPA)
announced
a
series
of
steps
that
the
Agency
would
undertake,
first,
to
achieve
reductions
in
the
amount
of
hazardous
waste
generated
in
this
country
and,
second,
to
ensure
the
safety
and
reliability
of
hazardous
waste
combustion
in
incinerators,
boilers,
and
industrial
furnaces.
With
this
announcement,
EPA
released
its
Draft
Hazardous
Waste
Minimization
and
Combustion
Strategy.
Eighteen
months
later,
EPA's
released
its
Final
Strategy
which
solidified
the
Agency's
policy
on
"
how
best
to
assure
the
public
of
safe
operation
of
hazardous
waste
combustion
facilities."
EPA's
Final
Strategy
specifically
recognized
the
multi­
pathway
risk
assessment
as
a
valuable
tool
for
evaluating
and
ensuring
protection
of
human
health
and
the
environment
in
the
permitting
of
hazardous
waste
combustion
facilities.

Region
6
believes
that
those
combustion
facilities
which
are
in
close
proximity
to
population
centers,
sensitive
ecosystems,
sensitive
receptors,
or
areas
that
may
have
high
potential
for
cumulative
environmental
impacts,
can
be
evaluated
by
a
multi­
pathway
risk
assessment
to
ensure
that
permit
limits
are
protective
of
human
health.
Furthermore,
EPA
Region
6
believes
that
multi­
pathway
risk
assessments
should
consider
the
specific
nature
of
process
operations
and
the
type
of
combustion
units
and
air
pollution
control
equipment
utilized
at
each
facility
in
order
to
be
representative
of
actual
facility
operations.
Region
6
staff
met
with
facility
representatives
and
LDEQ
staff
prior
to
completing
this
assessment,
in
order
to
develop
site­
specific
information.
Therefore,
although
certain
provisions
of
the
Resource
Conservation
and
Recovery
Act
(
RCRA)
program
have
since
been
delegated
to
the
States,
EPA
Region
6
is
committed
to
reviewing
facilities
on
a
site
specific
basis
to
evaluate
the
protectiveness
of
permits
for
combustion
operations.

EPA
Region
6,
in
partnership
with
the
Louisiana
Department
of
Environmental
Quality
(
LDEQ),
requested
more
comprehensive
testing
for
boiler
and
industrial
furnace
(
BIF)
combustion
facilities
in
the
State
of
Louisiana
as
part
of
the
regulatory
trial
burn
testing
conducted
during
early
1997
through
1998.
Although
the
science
of
combustion
risk
assessments
was
still
under
development,
BIF
facilities
agreed
to
conduct
more
comprehensive
testing
prior
to
EPA's
completion
of
the
revised
national
guidance
documents
for
combustion
emissions
testing
and
risk
assessment
protocols.
Based
upon
the
nature
of
their
operations,
EPA
allowed
BIF
facilities
to
demonstrate
their
performance
at
"
normal
operating
conditions"
during
the
trial
burn
by
adding
a
separate
"
risk
burn"
test
condition.
The
information
from
the
risk
burn
was
collected
with
the
intent
of
EPA
conducting
facility­
specific
human
health
risk
assessments.

In
October
1998,
EPA
released
its
Human
Health
Risk
Assessment
Protocol
for
Hazardous
Waste
Combustion
Facilities,
Peer
Review
Draft
(
EPA530­
D­
98­
001
A,
B,
and
C;
dated
July
1998),
commonly
referred
to
as
the
HHRAP.
In
February
2000,
EPA
released
its
Guidance
on
Collection
of
Emissions
Data
to
support
Site­
Specific
Risk
Assessments
at
Hazardous
Waste
Combustion
Facilities,
Peer
Review
Draft
(
EPA530­
D­
98­
002;
dated
August
1998).
EPA
has
also
released
an
Errata
to
the
HHRAP
(
EPA
Memo,
July
1999),
which
addresses
issues
specific
to
conducting
human
health
risk
assessments.
EPA
Region
6
has
utilized
the
information
provided
in
the
above
listed
guidance
documents,
as
well
as
information
gained
from
the
External
Peer
Review
of
the
HHRAP
and
Errata,
and
best
professional
judgement
to
complete
this
human
health
risk
assessment.
This
risk
assessment
report
documents
the
Agency's
effort
in
ensuring
protective
permit
limits
so
that
normal
combustion
facility
operations
do
not
pose
unacceptable
risks
to
surrounding
communities.
Page
2
of
17
EXECUTIVE
SUMMARY
Dupont
Dow
Elastomers,
L.
L.
C.,
Pontchartrain
(
DuPont)
applied
to
the
LDEQ
for
a
RCRA
permit
to
burn
hazardous
waste
in
a
BIF
unit
at
their
facility
located
in
LaPlace,
Saint
John
the
Baptist
Parish,
Louisiana.
In
order
to
assist
LDEQ
in
identifying
any
additional
permit
conditions
which
might
be
necessary
to
ensure
protection
of
human
health,
EPA
has
conducted
this
risk
assessment.
This
assessment
evaluates
those
potential
emissions
from
one
RCRA
point
source
at
the
Dupont
facility,
a
halogen
acid
furnace
(
HAF),
as
well
as
potential
fugitive
emissions
associated
with
the
RCRA
facility
operations.

EPA's
risk
assessment
indicates
that
"
normal
operations"
of
the
BIF
hazardous
waste
burning
unit
at
the
DuPont
facility
should
not
adversely
impact
human
health.
In
addition,
EPA's
risk
assessment
evaluates
riskbased
permit
limits
that
can
be
incorporated
into
the
RCRA
permit
in
order
to
supplement
regulatory
maximum
allowable
limits
and
ensure
protection
of
human
health
over
the
long
term.

Waste
Feed
(
WF)
and/
or
Emission
(
EM)
Rates
(
g/
s)

Metals
of
Concern
Recommended
Risk­
Based
1
Permit
Limit
Annual
Average
"
Normal
Operations"
Demonstrated
1
via
the
Risk
Burn
(
3
Runs
Data
Average)

Emissions
Test
/
Waste
Feed
Antimony
WF
8.61E­
4
ND
2
=
2.18E­
5
ND
2
=
7.18E­
4
Arsenic
WF
1.24E­
3
ND
2
=
1.56E­
6
ND
2
=
6.15E­
5
Barium
WF
1.67E­
2
7.55E­
5
ND
2
=
9.23E­
5
Beryllium
WF
1.24E­
4
ND
2
=
1.04E­
7
ND
2
=
5.13E­
6
Cadmium
WF
1.24E­
4
1.31E­
6
ND
2
=
1.03E­
5
Chromium
(
Total)
WF
5.64E­
4
7.16E­
5
5.64E­
4
Hexavalent
Chromium
(
Cr+
6)
EM
4.80E­
5
EM
1.58E­
5
=
22%
Total
Chromium4
Lead
WF
2.58E­
2
ND
2
=
1.93E­
5
ND
2
=
8.20E­
4
Mercury
(
Total)
WF
ND
3
@
1.54E­
5
ND
2
=
7.78E­
7
ND
2
=
1.54E­
5
Silver
WF
4.31E­
4
ND
2
=
2.49E­
6
ND
2
=
1.23E­
4
Thallium
WF
ND
3
@
4.15E­
3
ND
2
=
1.04E­
4
ND
2
=
4.15E­
3
Nickel
WF
7.48E­
3
N/
A
7.48E­
3
Selenium
WF
ND
@
1.70E­
3
N/
A
ND
2
=
1.70E­
3
Zinc
WF
1.49E­
3
N/
A
1.49E­
3
NOTES:
1.
Recommended
RCRA
Permit
Limits
are
based
upon
an
average
stack
gas
temperature
of
305
K
and
an
average
stack
gas
flow
rate
of
4.18
m3/
s;
both
of
these
parameters
were
demonstrated
during
the
risk
burn.
Page
3
of
17
2.
WF
ND
means
that
the
metal
was
not
detected
in
the
waste
feed
samples
and
EM
ND
means
that
the
metal
was
not
detected
in
the
emissions
samples;
the
detection
limits
were
used
to
calculate
the
rates
shown.
3.
The
Recommended
RCRA
Permit
Limit
is
set
at
the
non­
detect
value
for
waste
feed
samples
that,
at
most,
would
result
in
the
non­
detect
value
for
emissions
 
a
value
which
is
lower
than
the
calculated
value
evaluated
in
the
risk
assessment.
4.
The
value
demonstrated
during
the
Risk
Burn
is
based
upon
the
assumption
that
Hexavalent
Chromium
is
equal
to
22%
of
the
Total
Chromium
measured
during
the
risk
burn.
This
percentage
was
calculated
from
speciated
measurements
taken
during
the
Trial
Burn.

EPA
back­
calculated
risk­
based
annual
average
permit
limits
from
the
Adjusted
Tier
I
limit
for
each
metal
of
concern,
with
the
exception
of
chromium.
EPA
back­
calculated
the
risk­
based
annual
average
permit
limit
for
hexavalent
chromium
from
the
Tier
III
limit.
For
total
chromium
and
for
those
metals
not
having
regulatory
maximum
limits
specified
by
the
regulations
(
i.
e.,
nickel,
selenium,
and
zinc),
EPA
calculated
riskbased
limits
from
the
available
risk
burn
data
as
appropriate
(
e.
g.,
hexavalent
form
considerations
for
chromium).
EPA
then
used
the
calculated
limits
in
the
risk
assessment
in
order
to
show
permit
protectiveness
over
the
long
term.

Of
special
note,
mercury
and
thallium
were
not
detected
in
either
emissions
or
waste
feed
samples
collected
during
the
risk
burn.
The
initial
calculated
risk­
based
emission
rates
were
higher
than
the
non­
detected
emission
rate
values
demonstrated
during
the
Risk
Burn,
but
lower
than
their
corresponding
non­
detected
waste
feed
rates
 
due
to
the
different
detection
limits
achievable
for
emission
samples
versus
liquid
organic
waste
matrices.
Therefore,
the
mercury
and
thallium
recommended
permit
limits
are
set
at
their
corresponding
waste
feed
detection
limit
values
demonstrated
during
the
risk
burn.
The
waste
feed
detection
limits
demonstrated
during
the
risk
burn
for
each
of
these
metals
should
result
in
emissions
at
the
non­
detect
levels
demonstrated
during
the
risk
burn
 
levels
that
would
be
less
than
the
calculated
values
used
in
the
risk
assessment
and
shown
to
be
protective.

EPA
recommends
that
LDEQ
incorporate
all
of
the
annual
average
metal
feed
rate
limits
and
the
emission
rate
limit
listed
above
into
the
RCRA
permit.
EPA
evaluated
the
most
current
information
available
to
estimate
potential
impacts
to
human
health,
both
directly
via
inhalation,
incidental
soil
ingestion,
and
ingestion
of
drinking
water
(
via
surface
water
intakes),
and
indirectly
via
modeled
deposition
and
uptake
through
the
food
chain.
Emissions
data
collected
as
part
of
the
risk
burn,
operational
data
specific
to
the
DuPont
facility,
and
site­
specific
information
based
upon
the
facility's
location,
were
evaluated
and
considered
in
making
assumptions
and
in
predicting
risks
associated
with
long
term
operations.
The
risk
estimates
provided
in
this
risk
assessment
are
conservative
in
nature
and
represent
possible
future
risks,
based
upon
those
operating
conditions
evaluated
for
issuance
of
a
final
RCRA
combustion
permit.
If
operations
change
significantly,
or
land
use
changes
occur
which
would
result
in
more
frequent
potential
exposure
to
receptors,
risks
from
facility
operations
may
need
to
be
reevaluated.

BACKGROUND
INFORMATION
This
risk
assessment
report
presents
a
brief
description
of
the
facility
and
the
emission
sources
evaluated,
the
air
modeling
effort
conducted,
the
risk
modeling
effort
conducted,
and
EPA's
evaluation
of
risk
estimates
for
the
Dupont
Dow
Elastomers,
L.
L.
C.,
Pontchartrain
facility
("
Dupont
facility")
located
near
Laplace,
Saint
John
The
Baptist
Parish,
Louisiana.
EPA
utilized
the
Industrial
Source
Complex
Short
Term
Version
3
Program
(
EPA,
ISCST3
software)
for
air
modeling
and
the
Industrial
Risk
Assessment
Program
­
Health
(
Lakes
Environmental,
IRAP­
h
View
software
Version
1.7)
for
risk
modeling.
EPA
utilized
the
ArcView
Page
4
of
17
Program
(
Environmental
Systems
Research
Institute,
software
Version
3.1),
for
desktop
Geographical
Information
Systems
(
GIS),
for
all
mapping
efforts.
All
available
information
used
to
assess
risks
attributable
to
the
DuPont
facility
can
be
found
in
electronic
format,
converted
mainly
to
pdf
files,
in
appendices
enclosed
via
compact
disc
with
this
risk
assessment
report
as
follows:

Appendix
A:
Air
Modeling
Audit
Files
Input
and
Output
Air
Files
from
the
ISCT3
Model
Plot
Files
ISC
File
(
file
built
for
import
into
the
IRAP­
h
Project
File)
Appendix
B:
Spreadsheets
Surface
Roughness
Calculation
Source
Emission
Rate
Calculations
Transport
&
Fate
Parameters
Total
Organic
Emissions
(
TOE)
Factor
Appendix
C:
Mapping
Background
Maps
Land
Use
Shape
Files
Appendix
D:
Risk
Modeling
Modified
Parameters
Source
Information
from
the
IRAP­
h
Project
File
Receptor
Information
from
the
IRAP­
h
Project
File
Risk
Summary
Information
from
the
IRAP­
h
Project
File
Appendix
E:
IRAP­
h
View
Project
Files
Readme
File
DuPont.
ihb
­
All
Chemicals
Run,
with
metals
adjusted
to
risk­
based
permit
limits
DuPont
Metals.
ihb
­
Metals
Only
Run,
Regulatory
Metal
Limits
for
DuPont
facility
evaluated
Since
The
HHRAP
provides
generic
discussions
of
the
uncertainties
associated
with
each
major
component
of
the
risk
assessment
process,
this
report
only
discusses
those
uncertainties
particular
to
the
site
specific
results
evaluated
for
the
DuPont
facility.
References
are
provided
at
the
end
of
this
document.

Facility
and
Source
Information
The
DuPont
Pontchartrain
facility
is
located
along
US
Highway
61
near
LaPlace,
St
John
The
Baptist
Parish,
Louisiana.
The
facility
is
bordered
on
the
south
by
the
Mississippi
River,
on
the
west
by
the
town
of
Reserve,
on
the
north
by
the
Kansas
City
Southern
Railroad
and
open
agricultural
land,
and
on
the
east
by
the
town
of
LaPlace.
Land
use
surrounding
the
facility
consists
primarily
of
a
mix
of
rural
and
industrial
use,
including
residences,
commercial
businesses,
industrial
facilities,
agricultural
land,
surface­
water
bodies,
and
wetlands.

The
DuPont
facility's
chemical
manufacturing
process
generates
RCRA
hazardous
and
nonhazardous
waste
streams,
which
are
burned
in
the
facility's
halogen
acid
furnace
(
HAF).
The
HAF
is
operated
to
produce
an
important
co­
product,
hydrochloric
acid
(
HCl),
as
part
of
the
process
that
also
destroys
the
waste
organic
chemicals
that
are
normally
produced
in
the
manufacture
of
chloroprene
and
Neoprene(
R)
rubber.
Liquid
hazardous
wastes
are
stored
in
tanks
prior
to
introduction
into
the
furnace
and
then
pumped
through
process
piping
from
one
of
the
two
storage
tanks
to
one
or
both
liquid
injection
burners.
Page
5
of
17
The
major
components
of
the
HAF
were
designed
according
to
DuPont
specifications
and
fabricated
by
Trane
Thermal.
The
HAF
is
comprised
of
two
parallel
liquid
injection
combustion
chambers.
Each
combustion
chamber
is
a
vertical
cylinder
with
a
maximum
internal
diameter
of
5
feet
4
inches
and
an
overall
inside
length
of
9
feet
5.75
inches,
with
a
cross­
sectional
area
at
the
widest
section
being
22.3
square
feet.
Each
combustion
chamber
is
equipped
with
a
Trane
Thermal
LV­
24
vortex
burner
(
or
equivalent),
which
is
an
atomizing
axial
liquid
waste
fuel
burner
that
has
a
provision
for
annular
feed
of
an
auxiliary
fuel.

Each
burner
has
a
rated
capacity
of
24
million
British
thermal
units
per
hour
(
Btu/
hr),
resulting
in
a
total
design
capacity
for
the
HAF
of
48
million
Btu/
hr.
Each
burner
is
located
at
the
top
of
the
combustion
chamber
and
fires
downward
along
the
axis
of
the
vertical
chamber.
Liquid
is
atomized
by
either
pressurized
air
or
steam.
The
supply
pressure
of
the
atomization
fluid
to
each
nozzle
is
typically
60
to
100
pounds
per
square
inch
gauge
(
psig).
Natural
gas
is
the
only
auxiliary
fuel
used
in
the
HAF,
but
is
not
fed
to
the
furnace
during
normal
operations.
Natural
gas
is
fed
to
the
HAF
during
startup
in
order
to
obtain
the
minimum
combustion
chamber
temperature
and
also
during
automatic
waste
feed
cutoffs
to
keep
the
combustion
chamber
hot.

Combustion
products
from
the
HAF
are
controlled
by
an
air
pollution
control
(
APC)
system
that
consists
of
a
four­
stage
absorption
train
and
a
DynawaveTM
scrubber.
Combustion
products
from
each
combustion
chamber
enter
two
parallel
gas
cooling
spray
chambers
prior
to
being
routed
to
one
of
two
primary
water
absorbers
for
additional
cooling.
Product
gases
from
the
two
parallel
gas
cooling
systems
enter
a
single
common
water
absorption
train
consisting
of
a
secondary
absorber,
a
tertiary
absorber,
and
a
vent
scrubber.
Product
acid
from
the
primary
and
secondary
absorption
columns
flows
to
HCl
product
storage
tanks
located
onsite
(
product
acid
strength
generally
ranges
from
approximately
10
to
28
wt%
HCl).
HCl
remaining
in
the
cooled
product
gas
after
the
primary
absorbers
is
absorbed
in
the
re­
circulation
liquid
flowing
countercurrently
down
the
three
packed
absorption
columns.

Gases
exiting
the
vent
scrubber
enter
the
top
of
the
Dynawave
scrubber
where
they
collide
with
an
aqueous
scrubbing
liquid
containing
a
reducing
agent.
The
Dynawave
scrubber
effectively
removes
both
chlorine
and
residual
hydrogen
chloride
from
the
vent
scrubber
effluent.
Dynawave
scrubber
water
effluent
is
either
disposed
in
an
onsite
hazardous
waste
deep
injection
well
or
reused
as
feedwater
to
the
HAF
scrubbing
train.
Gases
leaving
the
Dynawave
scrubber
are
discharged
to
the
atmosphere
through
a
120­
foot
stack
by
an
induced
draft
fan
located
at
the
inlet
of
the
scrubber.
The
induced
draft
fan
consists
of
a
Robinson
Industries
Model
No.
RB­
1210­
4
or
an
equivalent
centrifugal
blower
with
a
rating
of
375
cubic
meters
per
minute
at
38
"

C.

The
HAF
is
equipped
with
many
automatic
controls
and
automatic
shutdown
systems
including
high
waste
feed
rate,
high
carbon
monoxide
in
the
exhaust
gases,
high
combustion
airflow
rate,
low
scrubber
blowdown,
and
low
Dynawave
scrubber
pH.
In
addition,
the
unit
also
has
dual
continuous
emissions
monitoring
systems
for
both
carbon
monoxide
and
oxygen.
The
entire
HAF
system
from
combustion
chambers
through
the
vent
scrubber
are
operated
under
negative
pressure
to
prevent
fugitive
emissions.
Fugitive
emissions
from
valves,
flanges,
and
pumps
are
controlled
through
a
Leak
Detection
and
Repair
Program
and
by
using
dual
mechanical
seal
pump
systems.

Dupont
operates
the
HAF
unit
under
an
Adjusted
Tier
I
status
for
all
metals
except
chromium,
which
simply
means
that
all
of
these
metals
fed
to
the
unit
are
assumed
to
be
emitted
in
the
stack
gas.
Therefore,
the
regulations
limit
all
stack
metal
emissions
except
chromium
based
upon
the
hourly
feed
rate
of
individual
metals
into
the
combustion
unit.
For
chromium,
DuPont
operates
the
HAF
under
a
Tier
III
status,
which
Page
6
of
17
means
that
the
permit
limit
for
chromium
is
based
on
the
average
of
stack
emissions
data
collected
during
the
trial
burn
rather
than
waste
feed
rates.
The
trial
burn
testing
demonstrated
greater
than
99.999
%
efficiency
for
destruction
and
removal
of
organic
materials,
and
system
removal
efficiency
ranging
from
90%
to
99%
for
trace
metals
associated
with
emissions
(
Metco
Environment,
1997).
In
addition,
the
trial
burn
testing
demonstrated
that
of
the
Total
Chromium
emitted,
only
22%
is
in
the
hexavalent
form.

LDEQ
and
EPA
provided
oversight
at
the
risk
burn
testing
as
well
as
the
trial
burn
testing
for
Dupont.
A
risk
burn
is
considered
an
additional
operating
condition
of
the
trial
burn
during
which
data
are
collected
to
demonstrate
that
the
hazardous
waste­
burning
HAF
unit
does
not
pose
an
unacceptable
health
risk
when
operating
at
typical
(
or
normal)
operating
conditions
over
the
long
term.
In
order
to
simulate
worst
case
wastes,
the
RCRA
hazardous
waste
streams
fed
into
the
HAF
during
the
risk
burn
at
the
DuPont
facility
included:
1)
HCl
waste;
2)
chloroprene
heel
waste
transported
from
the
Dupont
Dow
Louisville
facility;
3)
catalyst
sludge
receiver
waste;
and
4)
other
waste
organics.
Target
operating
conditions
for
the
risk
burn
included
the
following:
(
1)
liquid
waste
feed
rate
of
5,000
pounds
per
hour
(
lb/
hr);
(
2)
chlorine
feed
rate
of
2,500
lbs/
hr;
and
(
3)
combustion
chamber
temperature
at
1,500oC.
Measurements
taken
during
the
risk
burn
demonstrated
a
stack
gas
flow
rate
of
4.2
m3/
sec,
a
stack
gas
exit
velocity
of
25.17
m/
sec,
and
an
exit
temperature
of
305.22
K
(
32

C
or
90

F)
for
normal
operating
conditions
(
i.
e.,
these
measurements
are
averages
for
runs
reported
in
the
DuPont
Risk
Burn
Report,
April
1997,
Volume
1).
The
HAF
stack
is
36.58
meters
(
120
feet)
above
grade
and
has
an
inside
diameter
of
0.46
meters
(
1.5
feet)
at
its
exit.
The
DuPont
facility
voluntarily
conducted
stack
testing
for
all
metals,
as
well
as
the
required
waste
feed
sampling,
during
the
risk
burn.

Air
Modeling
EPA
used
the
ISCST3
for
determining
air
dispersion
and
deposition
of
compounds
resulting
from
operations
at
the
DuPont
facility
in
accordance
with
the
HHRAP.
EPA
evaluated
emission
sources
using
primarily
the
data
and
information
provided
in
the
DuPont
Risk
Burn
Report
dated
April
1997
and
revisions
dated
September
1997
and
supplemental
information
requested
by
EPA
and
provided
by
DuPont
in
the
"
Fugitive
Emission
Estimating
Data
Report"
dated
February
4
and
24,
1999.

EPA
modeled
two
separate
emission
sources
for
the
Dupont
facility:
one
stack
source,
the
HAF
and
one
volume
area
source
(
designated
as
F1)
to
account
for
fugitive
emissions
associated
with
ancillary
equipment
to
the
HAF
including
the
two
halogen
acid
furnace
feed
storage
tanks.
EPA
evaluated
emissions
from
the
HAF
as
if
operations
occur
for
365
days
per
year.

Universal
Transverse
Mercator
(
UTM)
projection
coordinates
in
North
American
Datum
revised
in
1983
(
NAD83)
for
each
source
are
as
follows:
for
the
HAF,
(
738542.65,
3327710.77);
and
for
F1
(
738580.46,
3327675.40).
EPA
used
a
stack
gas
flow
rate
of
4.2
m3/
sec,
a
stack
gas
exit
velocity
of
25.17
m/
sec,
and
a
stack
gas
exit
temperature
of
305.
22
K
(
90

F)
as
input
to
ISCST3.
EPA
used
a
height
of
5
meters
(
assumed
midpoint
of
height
of
equipment)
and
an
area
of
approximately
124
square
meters
(
m2)
for
evaluation
of
F1.

Modeling
for
the
Dupont
facility
was
based
upon
an
array
of
receptor
grid
nodes
at
100­
meter
spacing
out
to
a
distance
of
3
kilometers
from
the
facility
and
an
array
of
receptor
grid
nodes
at
500­
meter
spacing
between
a
distance
of
3
kilometers
and
out
to
a
distance
of
10
kilometers
from
the
facility.
Unitized
concentration
and
deposition
rates
were
determined
by
the
ISCST3
model
for
each
receptor
grid
node
for
use
in
assessing
risks.
Consistent
with
the
HHRAP,
water
body
and
watershed
air
parameter
values
were
obtained
from
the
single
Page
7
of
17
receptor
grid
node
array
without
need
for
executing
values
to
a
separate
array.

Terrain
elevations
based
on
90­
meter
spaced
USGS
digital
elevation
data
were
specified
for
all
receptor
grid
nodes.
Other
site­
specific
information
used
to
complete
the
ISCST3
model
included
the
most
current
surrounding
terrain
information,
surrounding
land
use
information,
facility
building
characteristics,
and
meteorological
data
available.
Meteorological
data
collected
over
a
5­
year
period
from
representative
National
Weather
Service
(
NWS)
stations
near
the
facility
were
used
as
inputs
to
the
ISCST3
model.
The
surface
data
was
collected
from
the
New
Orleans
NWS
station.
The
upper
air
data
was
collected
from
the
Boothville
(
1984,
1985,
1986,
and
1987)
and
Slidell
(
1989),
Texas
NWS
stations.

Model
runs
were
executed
for
accurate
evaluation
of
partitioning
of
all
compounds
specific
to
vapor
phase,
particle
phase,
and
particle­
bound
phase
runs.
In
addition,
particle
diameter
size
distributions
and
mass
fractions
for
each
source
stack
were
based
on
the
values
determined
during
the
risk
burn.
Appendix
A
contains
all
air
modeling
information
utilized
and
generated
for
the
DuPont
facility.

Compounds
of
Potential
Concern
(
COPCs)

EPA
identified
Compounds
of
Potential
Concern
(
COPCs)
in
accordance
with
the
HHRAP.
EPA
dropped
phthalate
compounds
from
the
risk
analysis
since
the
DuPont
facility
does
not
burn
plastics
or
materials
with
phthalate
plasticizers
and
since
phthalate
compounds
were
not
detected
in
any
of
the
risk
burn
runs.
In
addition,
EPA
eliminated
some
compounds
from
the
quantitative
risk
analysis
based
upon
availability
of
toxicity
data
and/
or
transport
and
fate
data.
Of
those
chemicals
dropped
from
the
risk
analysis,
none
were
actually
detected
in
emissions
samples.
Appendix
B
contains
EPA­
calculated
COPC­
specific
emission
rates
used
in
the
risk
assessment
for
each
source,
including
the
fugitives
area,
and
provides
justification
for
all
chemicals
dropped
from
the
risk
analysis.
EPA
input
these
COPC­
specific
emission
rates
directly
into
the
risk
model,
which
allowed
calculation
of
compound­
specific
media
concentrations
in
order
to
estimate
risks.

EPA
evaluated
both
waste
feed
and
stack
emissions
data
for
organic
and
inorganic
compounds
collected
during
the
risk
burn
conducted
between
April
23
and
24,
1997,
in
order
to
calculate
emission
rates.
EPA
reviewed
a
letter
from
the
facility
dated
September
10,
1999,
in
order
to
determine
a
site­
specific
upset
factor
of
1.001
for
use
in
calculation
of
COPC­
specific
emission
rates
for
organic
compounds.
EPA
used
an
upset
factor
of
1.0
for
inorganic
compounds
evaluated
at
the
Adjusted
Tier
I
and
Tier
III
limits
since
these
limits
are
maximum
regulatory
limits
based
upon
waste
feed
and
emissions
data
collected
as
part
of
the
facility's
Certification
of
Compliance
(
COC).
EPA
then
reviewed
the
COC
form
on
file,
dated
1997,
for
the
DuPont
facility
in
order
to
compare
the
Adjusted
Tier
I
levels
with
operations
data
collected
during
the
risk
burn.
Finally,
in
order
to
properly
assess
fugitive
emissions
associated
with
DuPont's
typical
operations,
EPA
evaluated
supplemental
information
provided
by
DuPont
in
the
"
Fugitive
Emission
Estimating
Data
Report"
dated
February
4
and
24,
1999.
This
document
provided
historical
information
on
the
typical
mix
of
specific
compounds
in
the
waste
feed
and
the
engineering
details
for
equipment
in
the
areas
being
evaluated.

Of
special
note,
EPA
initially
evaluated
DuPont's
maximum
allowable
regulatory
limits
for
the
HAF
unit
(
i.
e.,
most
metals
being
Adjusted
Tier
1
Feed
Rate
Limits,
hexavalent
chromium
being
a
Tier
III
Emission
Rate
Limit)
and
found
that
the
maximum
limits
for
several
metals
would
need
to
be
supplemented
with
lower
annual
average
limits
(
risk­
based
limits)
in
order
for
the
permit
to
be
protective
of
human
health.
Since
the
risk
burn
data
as
well
as
the
COC
form
for
the
DuPont
facility
show
that
typical
operations
result
in
emission
rates
which
are
orders
of
magnitude
below
the
maximum
allowable
regulatory
limits,
EPA
back­
calculated
risk­
based
annual
average
permit
limits
from
the
Tier
limit
for
each
metal
of
concern.
For
total
chromium
Page
8
of
17
and
for
those
metals
not
having
regulatory
maximum
limits
specified
by
the
regulations
(
i.
e.,
nickel,
selenium,
and
zinc),
EPA
calculated
risk­
based
limits
from
the
available
risk
burn
data
as
appropriate
(
e.
g.,
hexavalent
form
considerations
for
chromium).
EPA
then
used
the
calculated
limits
in
the
risk
assessment
in
order
to
show
permit
protectiveness
over
the
long
term.

Waste
Feed
(
WF)
and/
or
Emission
(
EM)
Rates
(
g/
s)

Metals
of
Concern
Regulatory
Tier­
Based
1
Permit
Limit
Max
Allowable
Recommended
Risk­
Based
2
Permit
Limit
Annual
Average
"
Normal
Operations"
Demonstrated
2
via
the
Risk
Burn
(
3
Runs
Data
Average)

Emissions
Test
/
Waste
Feed
Antimony
WF
8.61E­
1
WF
8.61E­
4
ND
3
=
2.18E­
5
ND3
=
7.18E­
4
Arsenic
WF
1.24E­
3
WF
1.24E­
3
ND
3
=
1.56E­
6
ND3
=
6.15E­
5
Barium
WF
1.67E+
0
WF
1.67E­
2
7.55E­
5
ND
3
=
9.23E­
5
Beryllium
WF
1.24E­
3
WF
1.24E­
4
ND
3
=
1.04E­
7
ND
3
=
5.13E­
6
Cadmium
WF
1.24E­
3
WF
1.24E­
4
1.31E­
6
ND
3
=
1.03E­
5
Chromium
(
Total)
N/
A
WF
5.64E­
4
7.16E­
5
5.64E­
4
Hexavalent
Chromium
(
Cr
6+)
EM
2.35E­
3
EM
4.80E­
5
EM
1.58E­
5
=
22%
Total
Chromium5
Lead
WF
2.58E­
1
WF
2.58E­
2
ND
3
=
1.93E­
5
ND
3
=
8.20E­
4
Mercury
(
Total)
WF
8.61E­
1
WF
4
ND
@
1.54E­
5
ND
3
=
7.78E­
7
ND
3
=
1.54E­
5
Silver
WF
4.31E­
1
WF
4.31E­
4
ND
3
=
2.49E­
6
ND
3
=
1.23E­
4
Thallium
WF
8.61E­
1
WF
4
ND
@
4.15E­
3
ND
3
=
1.04E­
4
ND
3
=
4.15E­
3
Nickel
N/
A
WF
7.48E­
3
N/
A
7.48E­
3
Selenium
N/
A
WF
ND
@
1.70E­
3
N/
A
ND
3
=
1.70E­
3
Zinc
N/
A
WF
1.49E­
3
N/
A
1.49E­
3
NOTES:
1.
Regulatory
Permit
Limits
are
based
upon
the
Tier
Level
requested
by
the
facility.
DuPont
currently
operates
under
Adjusted
Tier
1
status
for
all
metals
except
Chromium,
which
is
specified
under
Tier
III
in
the
Hexavalent
form.
2.
Recommended
RCRA
Permit
Limits
are
based
upon
an
average
stack
gas
temperature
of
305
K
and
an
average
stack
gas
flow
rate
of
4.18
m3/
s;
both
of
these
parameters
were
demonstrated
during
the
risk
burn.
3.
WF
ND
means
that
the
metal
was
not
detected
in
the
waste
feed
samples
and
EM
ND
means
that
the
metal
was
not
detected
in
the
emissions
samples;
the
detection
limits
were
used
to
calculate
the
rates
shown.
4.
The
Recommended
RCRA
Permit
Limit
is
set
at
the
non­
detect
value
for
waste
feed
samples
that,
at
most,
would
result
in
the
non­
detect
value
for
emissions
 
a
value
which
is
lower
than
the
calculated
value
evaluated
in
the
risk
assessment.
5.
The
value
demonstrated
during
the
Risk
Burn
is
based
upon
the
assumption
that
Hexavalent
Chromium
is
equal
to
22%
of
the
Total
Chromium
measured
during
the
risk
burn.
This
percentage
was
calculated
from
speciated
measurements
taken
during
the
Trial
Burn.
Page
9
of
17
As
the
above
comparison
shows,
DuPont
demonstrated
during
the
risk
burn
that
feed
rate
limits
during
"
normal
operations"
fall
at
(
non­
detects)
or
below
the
recommended
permit
limits.

EXPOSURE
ASSESSMENT
Exact
locations
where
people
can
potentially
be
exposed
to
contaminants
in
the
air,
surface
water,
or
soil
are
determined
by
the
grid
spacing
used
in
the
air
model
and
subsequently
imported
into
the
risk
model.
These
specific
locations
can
be
used
for
assessing
exposure
for
a
particular
type
of
receptor
based
upon
the
land
use
type
being
evaluated
(
i.
e.,
farming
or
residential).
Since
plants
or
animals
can
also
be
exposed
to
contaminants
at
these
coordinates
points,
possible
uptake
through
the
food
chain
can
be
assessed
based
upon
the
type
of
land
use
designated.

The
potential
exposure
scenarios
evaluated
in
this
risk
assessment
include
both
adult
and
child
receptors
for
the
following
land
use
types:
residential,
subsistence
farming,
and
subsistence
fishing.
In
all
cases,
EPA
used
default
values
for
receptor
specific
parameters,
as
outlined
in
the
HHRAP.
However,
for
dioxins
and
furans,
EPA
used
updated
bioaccumulation
factors
and
toxicity
equivalency
values
based
upon
the
results
of
the
External
Peer
Review
of
the
HHRAP
Guidance
(
External
Peer
Review
Meeting,
May
2000).
Please
see
the
Uncertainty
Section
of
this
risk
assessment
for
a
discussion
of
those
parameters
modified
for
specific
dioxin/
furan
cogeners.
Current
land
use
was
considered
in
determining
those
receptors
potentially
impacted
by
identified
emission
sources,
while
potential
future
land
use
was
assumed
to
be
the
same
as
current
land
use.

Study
Area
Characterization
Although
the
study
area
for
air
modeling
purposes
extends
out
approximately
10
kilometers
from
the
HAF,
the
risk
assessment
evaluated
possible
exposure
based
upon
potential
receptors
located
closer
to
the
facility
where
the
reasonable
maximum
risks
to
various
types
of
receptors
might
occur.
Specifically,
discrete
land
use
areas
where
results
of
the
air
modeling
indicated
maximum
air
concentration
or
maximum
deposition
of
COPCs
might
occur
typically
fell
within
a
3
kilometer
radius
from
the
HAF.
EPA
then
evaluated
multiple
locations
within
each
discrete
land
use
area
potentially
impacted,
in
accordance
with
the
HHRAP.
This
ensured
that
all
possible
receptors
were
evaluated
for
identifying
reasonable
maximum
risks
for
each
exposure
scenario
type.

Potentially
impacted
water
bodies
and
their
associated
effective
watershed
areas
were
also
evaluated
as
part
of
the
risk
assessment.
EPA
evaluated
the
following
water
bodies:
Mississippi
River,
LaPlace
Ponds
(
North
and
South),
and
Bonnet
Carre
Point.
Although
some
of
the
ponds
may
not
currently
be
used
for
fishing,
EPA
evaluated
each
pond
for
fishing
consumption
based
upon
the
potential
for
fishing
to
occur.
Additionally,
LaPlace
currently
obtains
its
drinking
water
from
the
Mississippi
River
adjacent
to
the
Lyons
subdivision
within
the
3
kilometer
radius
of
the
facility
so
this
portion
of
the
river
was
evaluated
for
drinking
water
use.
These
assumptions
may
have
been
overly
conservative
for
evaluation
of
current
use,
but
did
not
require
further
evaluation
since
resulting
risks
for
the
drinking
water
and
fish
consumption
pathways
were
well
below
EPA
levels
of
concern.

EPA
contractors
conducted
a
site
visit
to
verify
information
shown
on
digitized
land
use
land
cover
maps,
topographic
maps,
and
aerial
photographs.
EPA
utilized
the
internet
to
locate
and
verify
local
schools
and
daycare
facilities
on
the
topographic
maps.
EPA
also
requested
and
obtained
input
from
LDEQ
and
facility
Page
10
of
17
representatives
on
actual
land
use
designations
used.
Appendix
C
contains
the
topographic,
land
use,
and
watershed
maps
which
show
the
specific
areas
evaluated
as
part
of
the
study
area
 
as
well
as
those
effective
watershed
areas
specific
to
this
risk
assessment.

Exposure
Scenario
Locations
The
exposure
scenario
locations
in
this
risk
assessment
were
chosen
to
be
representative
of
potential
maximally
exposed
individuals,
or
receptors,
within
each
representative
land
use
type.
EPA
also
evaluated
receptors
where
actual
land
use
dictated
consideration
of
special
sub­
populations,
as
defined
in
the
HHRAP.
However,
all
of
these
locations
were
already
being
accounted
for
by
placement
of
nearby
residential
receptors
(
i.
e.,
inclusive
of
children).
Infant
potential
exposure
to
dioxins
and
furans
via
the
ingestion
of
their
mother's
breast
milk
is
evaluated
at
corresponding
adult
scenario
locations
(
i.
e.,
locations
where
the
mother
may
live).
Receptor
locations
for
a
child's
potential
exposure
to
lead
in
soil
and
air
are
the
same
as
the
various
child
scenario
locations.
Fisher
receptors
were
placed
at
residential
scenario
locations
near
each
water
body
evaluated.
All
exposure
scenario
locations
are
shown
on
those
topographic
maps
provided
in
Appendix
C,
and
are
also
provided
via
a
coordinate
list
exported
from
the
risk
model
project
file
in
Appendix
D.

Transport
and
Fate
Parameters
EPA
used
transport
and
fate
equations
presented
in
the
HHRAP
to
determine
air,
soil,
and
surface
water
COPC­
specific
concentrations.
Those
equations
which
determine
uptake
of
specific
COPCs
in
the
food
chain
(
i.
e.,
COPC
concentrations
in
fish,
pork,
milk,
eggs,
etc.)
allow
the
use
of
parameters
derived
as
either
default
values,
also
provided
in
the
HHRAP,
or
facility/
site­
specific
values,
as
available
and
appropriate.
Site­
specific
transport
and
fate
parameters
utilized
for
the
DuPont
facility
include
universal
soil
loss
constants,
delineation
of
water
body
and
effective
watershed
areas
potentially
impacted
by
facility
sources,
water
body
depth,
and
average
annual
total
suspended
solids
concentration.

Of
special
note
is
EPA's
decision
to
use
40
years
for
the
time
of
COPCs
deposition
(
i.
e.,
facility
operational
time),
rather
than
the
100
years
recommended
by
the
HHRAP.
EPA
Region
6
considerations
in
using
40
years
as
opposed
to
100
years
include
the
following:
1)
the
longest
receptor
exposure
duration
is
40
years;
and
2)
RCRA
permit
renewals
are
required
every
10
years
so
risks
can
be
reevaluated
at
any
time
utilizing
the
most
current
transport
and
fate
information
available
at
that
time.

Site­
specific
transport
and
fate
parameters
are
provided
in
the
spreadsheet
provided
in
Appendix
B.
COPCspecific
chemical
and
physical
parameters
are
not
provided
in
this
risk
assessment
report
since
they
can
be
found
in
Appendix
A
of
the
HHRAP
and
also
in
EPA's
July
1999
Errata
to
the
HHRAP.
The
IRAP­
h
View
Version
1.7
utilizes
all
updated
information
found
in
EPA's
Errata
to
the
HHRAP.

RISK
CHARACTERIZATION
In
this
risk
assessment,
EPA
evaluated
chronic
excess
risk
estimates
for
both
direct
exposure
pathways,
or
those
pathways
where
contact
may
occur
with
a
contaminated
media
(
i.
e,
inhalation,
incidental
soil
ingestion,
and
ingestion
of
drinking
water),
and
also
indirect
pathways
(
i.
e.,
those
risks
associated
with
uptake
through
the
food
chain).
EPA
also
evaluated
the
potential
for
non­
carcinogenic
health
effects
to
occur
by
calculation
of
hazard
indices
(
HIs)
for
the
various
COPCs
identified
at
the
DuPont
facility.
In
addition,
EPA
assessed
the
following:
1)
potential
acute
effects
(
i.
e.,
risks
associated
with
short­
term
emissions)
from
inhalation;
2)
potential
impacts
from
possible
accumulation
of
dioxin
and
furan
compounds
in
breastmilk;
and
3)
potential
Page
11
of
17
adverse
impacts
for
small
children
(
i.
e.,
children
under
6
years
old)
who
are
susceptible
to
lead
exposure
in
surface
soils
and
ambient
air.

For
those
chemicals
detected
in
stack
gas
emissions
or
quantified
as
fugitive
source
emissions
at
the
DuPont
facility,
EPA
found
that
RCRA
operations
should
not
pose
adverse
impacts
for
any
of
the
receptors
evaluated.
For
those
chemicals
not
actually
detected
in
stack
gas
emissions
or
not
detected
in
the
waste
feed
analysis,
please
see
the
Uncertainty
Section
of
this
report.
EPA
used
target
action
levels
identified
in
the
Region
6
Risk
Management
Addendum
­
Draft
Human
Health
Risk
Assessment
Protocol
for
Hazardous
Waste
Combustion
Facilities
(
EPA­
R6­
98­
002,
July
1998)
to
evaluate
resulting
risk
estimates.

Excess
Cancer
Risks
For
those
COPCs
detected
in
stack
gas
emissions
or
quantified
as
fugitive
source
emissions
at
the
DuPont
facility,
chronic
excess
cancer
risk
estimates
attributed
to
both
direct
exposure
pathways
and
indirect
exposure
pathways
are
all
well
below
EPA's
1
x
10­
5
level
of
concern
for
all
receptors
evaluated.
This
means
that
there
is
less
than
one
chance
in
one
hundred
thousand
of
a
person
getting
cancer
from
possible
exposure
to
RCRA
combustion
emissions
associated
with
the
DuPont
facility.

Excess
cancer
risk
estimates
for
each
receptor,
delineated
by
source
and
specific
COPC,
are
provided
via
a
summary
table
exported
from
the
risk
model
project
file,
"
copc_
risk"
in
Appendix
D.
In
addition,
excess
cancer
risk
estimates
for
each
receptor,
delineated
by
pathway,
are
provided
in
a
summary
table
exported
from
the
risk
model
project
file,
"
pathway"
in
Appendix
D.
The
next
to
last
column
of
each
table
contains
the
excess
cancer
risk
estimates.

Non­
Carcinogenic
Health
Effects
For
those
COPCs
detected
in
stack
gas
emissions
or
quantified
as
fugitive
source
emissions,
the
HIs
associated
with
both
direct
and
indirect
pathways
are
all
well
below
EPA's
0.25
level
of
concern
for
all
receptors
evaluated.
This
means
that
a
person's
health
should
not
be
adversely
effected
by
possible
exposure
to
RCRA
combustion
emissions
at
the
DuPont
facility.

The
HI
estimates
for
each
receptor,
delineated
by
source
and
specific
COPC,
are
provided
via
a
summary
table
exported
from
the
risk
model
project
file,
"
copc_
risk"
in
Appendix
D.
In
addition,
HI
estimates
for
each
receptor,
delineated
by
pathway,
are
provided
in
a
summary
table
exported
from
the
risk
model
project
file,
"
pathway"
in
Appendix
D.
The
last
column
of
each
table
contains
the
HI
estimates.

Other
Risks
Acute
Hazard
Quotients
are
all
less
than
1.0
for
those
receptors
evaluated.
This
means
that
a
person's
health
should
not
be
adversely
effected
from
direct
inhalation
of
the
maximum
1­
hour
concentration
of
vapors
and/
or
particulates
associated
with
RCRA
combustion
emissions
at
the
DuPont
facility.
An
acute
adverse
health
effect
is
defined
here
as
a
concentration
intended
to
protect
the
general
public
from
discomfort
or
mild
adverse
health
effects
over
1
hour
of
possible
exposure.
See
the
summary
table
exported
from
the
risk
model
project
file,
"
acute"
in
Appendix
D.
For
dioxin­
like
compounds,
calculations
show
that
projected
possible
intakes
for
babies
who
are
breastfed
are
all
well
below
the
average
infant
intake
target
level
of
60
pg/
kg­
day
of
2,3,7,8­
TCDD
Equivalents.
See
the
summary
table
exported
from
the
risk
model
project
file,
"
b­
milk"
in
Appendix
D.
More
detailed
information
relating
to
dioxins
and
potential
exposure
and
risk
characterization
for
dioxins
can
be
found
at
Page
12
of
17
the
EPA
website
http://
www.
epa.
gov/
nceawww1/
dioxin.
htm
(
contains
documents
generated
as
part
of
the
Dioxin
Reassessment
Initiative).

For
lead,
calculations
show
that
projected
possible
concentrations
in
surface
soils
and
ambient
air
should
not
exceed
EPA
target
levels
of
100
mg/
kg
and
0.2
µ
g/
m3,
respectively.
This
means
that
concentrations
of
lead
predicted
to
occur
in
soils
and
ambient
air
from
RCRA
combustion
emissions
at
the
DuPont
facility
are
at
levels
which
should
not
adversely
impact
the
health
of
children
under
the
age
of
6
years
old
(
i.
e.,
those
children
who
are
susceptible
to
health
impacts
from
lead
exposure).
See
the
summary
table
exported
from
the
risk
model
project
file,
"
lead"
in
Appendix
D.

UNCERTAINTY
DISCUSSION
Uncertainty
is
inherent
in
any
risk
assessment
process,
and
in
the
case
of
combustion
risk
assessments,
can
become
complex
in
consideration
of
the
necessary
integration
of
various
data,
process
parameters,
and
modeling
efforts
undertaken.
Uncertainties
and
limitations
of
the
risk
assessment
process
are
discussed
in
general
in
Chapter
8
of
the
HHRAP
and
in
more
detail
in
each
separate
chapter
of
the
HHRAP.
Therefore,
this
risk
assessment
will
not
reiterate
that
lengthy
discussion,
but
will
complement
it
by
addressing
specific
key
areas
of
interest
which
were
identified
during
EPA's
evaluation
of
resulting
risk
estimates
at
the
DuPont
facility.
Some,
if
not
all,
of
these
areas
of
interest
have
been
identified
by
other
EPA
regions
and/
or
State
partners
conducting
risk
assessments
at
similar
combustion
facilities
across
the
country.

Modified
Parameters
for
Dioxins/
Furans
Please
see
the
"
Modified
Parameters"
file
in
Appendix
D
for
an
all­
inclusive
parameter
list
of
chemicalspecific
values
used
in
this
human
health
risk
assessment
(
i.
e.,
a
side­
by­
side
comparison
of
the
modified
value
versus
the
original
default
value
for
each
COPC­
specific
parameter).
For
the
DuPont
facility,
the
only
compounds
where
chemical­
specific
values
were
modified
include
individual
dioxin/
furan
cogeners.
Modifications
are
based
upon
input
from
the
External
Peer
Review
of
EPA's
HHRAP
and
Errata
(
External
Peer
Review
Meeting,
May
2000).

In
determining
the
bioaccumulation
factors
for
chickens
(
Ba
chicken)
and
eggs
(
Ba
egg),
as
published
in
the
July
1999
Errata
to
the
HHRAP,
EPA
assumed
that
the
bioconcentration
factors
(
BCFs)
presented
in
the
1995
Stephens,
Petreas,
and
Hayward
paper
were
calculated
as
the
ratio
of
the
dioxin/
furan
concentration
in
tissue
to
the
concentration
in
soil.
However,
the
BCFs
were
actually
calculated
as
the
ratio
of
dioxin/
furan
concentration
in
tissue
to
the
concentration
in
feed.
Therefore,
since
the
soil/
feed
mixture
fed
to
the
chickens
was
one
part
soil
and
nine
parts
feed
(
1:
9),
the
bioaccumulation
factors
presented
in
the
Errata
would
appear
to
be
ten­
fold
too
high.
Therefore,
EPA
reduced
the
Ba
chicken
and
BA
egg
values
provided
in
the
Errata
by
a
factor
of
10
for
those
cogeners
evaluated
(
"
Biotransfer
and
Bioaccumulation
of
Dioxins
and
Furans
from
Soil:
Chickens
as
a
Model
for
Foraging
Animals";
Stephens,
Petreas,
and
Hayward,
1995).

Additionally,
since
publication
of
the
July
1999
Errata
to
the
HHRAP,
EPA's
Office
of
Solid
Waste
has
recommended
use
of
the
1997
World
Health
Organization
(
WHO,
1997)
Toxicity
Equivalency
Factors
(
TEFs)
for
dioxin/
furan
cogeners.
Therefore,
EPA
Region
6
changed
appropriately
those
three
cogeners
where
TEFs
specified
in
the
HHRAP
were
different
than
the
WHO
values
recommended
for
human
health
Page
13
of
17
risk
assessments
(
i.
e.,
1997
WHO
TEFs
for
fish,
mammals,
and
birds).

Bio­
Transfer
Factors
In
completing
the
evaluation
of
risk
estimates
for
the
DuPont
facility,
EPA
has
noted
that
biotransfer
factors
are
primarily
responsible
for
artificially
high
risk
estimates
for
certain
compounds.
Specifically,
two
polycyclic
aromatic
compounds
(
PAHs)
were
identified
for
further
evaluation
when
resulting
risk
estimates
seemed
disproportionate
for
the
low
level
emission
rates
(
i.
e.,
rates
based
upon
non­
detected
levels)
used
in
the
DuPont
risk
assessment:

indeno(
1,2,3­
cd)
pyrene
and
dibenz(
a,
h)
anthracene
The
farmer
scenario
uses
beef
and
milk
biotransfer
factors
based
upon
the
n­
octanol/
water
partition
coefficient
(
K
ow),
as
specified
in
the
HHRAP.
However,
the
HHRAP
also
provides
discussion
about
the
possibility
of
decreasing
(
rather
than
increasing)
biotransfer
values
with
increasing
K
ow
values.
The
two
PAH
compounds
in
question
fall
within
the
range
cited
(
log
K
ow
between
6.5
and
8.0).
The
HHRAP
suggests
that
this
trend
may
be
due
to
a
greater
rate
of
metabolism
of
higher
K
ow
compounds
(
HHRAP,
Volume
2,
Appendix
A
pages
A­
3­
25
thru
A­
3­
26).
In
addition,
other
literature
sources
(
Gorelova
and
Cherepanova,
1970;
Gorelova
et
al.,
1970)
acknowledge
that
PAHs
with
large
K
ow
values
are
readily
metabolized
by
the
mixed
function
oxidase
metabolic
pathway
in
mammals
to
water­
soluble
substances,
which
are
then
excreted.
Therefore,
the
resulting
risk
estimates
for
these
two
PAHs
may
be
biased
high.
In
other
words,
EPA
believes
that
the
potential
risk
from
exposure
to
these
two
compounds
is
not
of
concern
since
these
two
PAHs
tend
not
to
bioaccumulate
in
animal
or
human
tissue,
but
rather
to
be
metabolized
and
excreted.

Use
of
Non­
Detected
Compounds
Compounds
which
were
quantified
as
not
present
at
or
above
a
laboratory
specified
reporting
limit
but
could
possibly
be
formed
as
products
of
incomplete
combustion,
were
used
in
calculation
of
risk
estimates.
For
example,
PAHs
are
semi­
volatile
compounds
typically
associated
with
combustion
sources.
Therefore,
EPA
retained
and
considered
these
compounds
in
the
risk
assessment
in
accordance
with
the
HHRAP
even
though
they
were
not
detected
in
any
of
the
analyses
conducted.

Additionally,
EPA
followed
the
HHRAP
in
determining
the
appropriate
detection
limits
to
use
in
estimating
emission
rates
for
non­
detected
compounds.
However,
since
the
HHRAP
does
not
address
the
appropriate
detection
limit
for
waste
feed
samples,
EPA
used
Sample
Quantitation
Limits
(
SQLs)
to
calculate
emission
rates
for
non­
detected
compounds,
as
reported
by
the
laboratory.
Conceptually,
SQLs
are
the
most
appropriate
detection
limit
to
use
for
waste
matrices
where
compounds
are
suspected
to
be
present
but
interferences
may
occur
to
obscure
the
detection
of
certain
compounds
as
presented
in
EPA's
Guidance
for
Data
Useability
in
Risk
Assessment
(
Publication
9285.7­
090A;
April
1992).

Although
using
non­
detected
compounds
may
tend
to
overestimate
risks
to
some
degree,
all
compounds
which
were
retained
in
the
DuPont
risk
assessment
resulted
in
risk
estimates
well
below
EPA
levels
of
concern
with
the
exception
of
two
PAH
compounds.
The
same
two
PAH
compounds
discussed
in
the
prior
section
were
not
detected
in
stack
emissions,
but
were
assumed
to
be
present
at
their
Reliable
Detection
Page
14
of
17
Level
(
RDL).
In
other
words,
in
addition
to
risk
estimates
for
these
two
compounds
being
biased
high
due
to
use
of
biotransfer
factors
which
do
not
account
for
metabolization,
the
risk
estimates
may
also
be
biased
high
due
to
use
of
emission
rates
based
upon
non­
detected
values.
Therefore,
EPA
believes
that
these
two
PAH
compounds
do
not
actually
pose
adverse
health
impacts
 
even
assuming
the
compounds
are
present
at
their
RDLs.

Compounds
Dropped
from
Quantitative
Analysis
Of
those
compounds
dropped
from
the
risk
analysis
due
to
a
lack
of
toxicity
or
transport
and
fate
information,
none
of
the
chemicals
dropped
were
actually
detected
in
the
emissions
data.
Since
these
compounds
do
not
have
toxicity
data
and/
or
transport
and
fate
information,
and
since
they
were
not
detected
in
emissions,
they
can
not
be
quantitatively
or
even
qualitatively
evaluated
in
the
risk
assessment.

Unidentified
Organic
Compounds
DuPont
conducted
Total
Organic
Emissions
(
TOE)
testing
in
accordance
with
the
HHRAP.
Permitting
authorities
need
this
information
to
address
concerns
about
the
unknown
fraction
of
organic
emissions
from
combustion
units.
Using
the
TOE
test
results,
and
the
speciated
data
from
the
Risk
Burn,
EPA
calculated
a
TOE
factor
which
falls
at
the
low
end
of
the
range
anticipated
in
the
HHRAP
(
2
­
40).
Based
upon
these
results,
and
the
process
information
available
for
the
DuPont
facility,
EPA
believes
that
unidentified
organic
compounds
do
not
contribute
significantly
to
those
risk
estimates
calculated
in
this
risk
assessment.
Page
15
of
17
CONCLUSION
&
RECOMMENDATIONS
EPA's
risk
assessment
indicates
that
"
normal
operations"
of
the
BIF
units
at
the
DuPont
facility
should
not
adversely
impact
human
health.
Additionally,
EPA's
risk
assessment
shows
that
the
appropriate
regulatory
maximum
permit
limits
(
Adjusted
Tier
1
Feed
Rate
Limits
and
Tier
II
Emission
Rate
Limit
for
Hexavalent
Chromium)
for
the
DuPont
hazardous
waste
combustion
unit
should
be
supplemented
with
lower
annual
average
limits
(
risk­
based
limits)
for
several
metals
in
order
for
the
permit
to
be
protective
of
human
health.
Therefore,
EPA
recommends
that
LDEQ
incorporate
the
annual
average
permit
limits
listed
below
into
the
RCRA
permit.
Waste
Feed
(
WF)
and/
or
Emission
(
EM)
Rates
(
g/
s)

Metals
of
Concern
Regulatory
Tier­
Based
1
Permit
Limit
Max
Allowable
Recommended
Risk­
Based
2
Permit
Limit
Annual
Average
"
Normal
Operations"
Demonstrated
2
via
the
Risk
Burn
(
3
Runs
Data
Average)

Emissions
Test
/
Waste
Feed
Antimony
WF
8.61E­
1
WF
8.61E­
4
ND
3
=
2.18E­
5
ND3
=
7.18E­
4
Arsenic
WF
1.24E­
3
WF
1.24E­
3
ND
3
=
1.56E­
6
ND3
=
6.15E­
5
Barium
WF
1.67E+
0
WF
1.67E­
2
7.55E­
5
ND
3
=
9.23E­
5
Beryllium
WF
1.24E­
3
WF
1.24E­
4
ND
3
=
1.04E­
7
ND
3
=
5.13E­
6
Cadmium
WF
1.24E­
3
WF
1.24E­
4
1.31E­
6
ND
3
=
1.03E­
5
Chromium
(
Total)
N/
A
WF
5.64E­
4
7.16E­
5
5.64E­
4
Hexavalent
Chromium
(
Cr
6+)
EM
2.35E­
3
EM
4.80E­
5
EM
1.58E­
5
=
22%
Total
Chromium5
Lead
WF
2.58E­
1
WF
2.58E­
2
ND
3
=
1.93E­
5
ND
3
=
8.20E­
4
Mercury
(
Total)
WF
8.61E­
1
WF
4
ND
@
1.54E­
5
ND
3
=
7.78E­
7
ND
3
=
1.54E­
5
Silver
WF
4.31E­
1
WF
4.31E­
4
ND
3
=
2.49E­
6
ND
3
=
1.23E­
4
Thallium
WF
8.61E­
1
WF
4
ND
@
4.15E­
3
ND
3
=
1.04E­
4
ND
3
=
4.15E­
3
Nickel
N/
A
WF
7.48E­
3
N/
A
7.48E­
3
Selenium
N/
A
WF
ND
@
1.70E­
3
N/
A
ND
3
=
1.70E­
3
Zinc
N/
A
WF
1.49E­
3
N/
A
1.49E­
3
NOTES:
1.
Regulatory
Permit
Limits
are
based
upon
the
Tier
Level
requested
by
the
facility.
DuPont
currently
operates
under
Adjusted
Tier
1
status
for
all
metals
except
Chromium,
which
is
specified
under
Tier
III
in
the
Hexavalent
form.
2.
Recommended
RCRA
Permit
Limits
are
based
upon
an
average
stack
gas
temperature
of
305
K
and
an
average
stack
gas
flow
rate
of
4.18
m3/
s;
both
of
these
parameters
were
demonstrated
during
the
risk
burn.
3.
WF
ND
means
that
the
metal
was
not
detected
in
the
waste
feed
samples
and
EM
ND
means
that
the
metal
Page
16
of
17
was
not
detected
in
the
emissions
samples;
the
detection
limits
were
used
to
calculate
the
rates
shown.
4.
The
Recommended
RCRA
Permit
Limit
is
set
at
the
non­
detect
value
for
waste
feed
samples
that,
at
most,
would
result
in
the
non­
detect
value
for
emissions
 
a
value
which
is
lower
than
the
calculated
value
evaluated
in
the
risk
assessment.
5.
The
value
demonstrated
during
the
Risk
Burn
is
based
upon
the
assumption
that
Hexavalent
Chromium
is
equal
to
22%
of
the
Total
Chromium
measured
during
the
risk
burn.
This
percentage
was
calculated
from
speciated
measurements
taken
during
the
Trial
Burn.

As
the
above
comparison
shows,
DuPont
demonstrated
during
the
risk
burn
that
feed
rate
limits
during
"
normal
operations"
fall
at
(
non­
detects)
or
below
the
recommended
permit
limits.

EPA
evaluated
the
most
current
information
available
to
estimate
potential
impacts
to
human
health,
both
directly
via
inhalation,
incidental
soil
ingestion,
and
ingestion
of
drinking
water
(
via
surface
water
intakes),
and
indirectly
via
modeled
deposition
and
uptake
through
the
food
chain.
Emissions
data
collected
as
part
of
the
risk
burn,
operational
data
specific
to
the
DuPont
facility,
and
site­
specific
information
based
upon
the
facility's
location,
were
evaluated
and
considered
in
making
assumptions
and
in
predicting
risks
associated
with
long
term
operations.
The
risk
estimates
provided
in
this
risk
assessment
are
conservative
in
nature
and
represent
possible
future
risks,
based
upon
those
operating
conditions
evaluated
for
issuance
of
a
final
RCRA
combustion
permit.
If
operations
change
significantly,
or
land
use
changes
occur
which
would
result
in
more
frequent
potential
exposure
to
receptors,
risks
from
facility
operations
may
need
to
be
reevaluated.
Page
17
of
17
REFERENCES
1.
Human
Health
Risk
Assessment
Protocol
for
Hazardous
Waste
Combustion
Facilities,
Peer
Review
Draft
(
EPA530­
D­
98­
001
A,
B,
and
C;
July
1998);
Errata
to
the
HHRAP
(
EPA,
July
1999).

2.
Guidance
on
Collection
of
Emissions
Data
to
Support
Site­
Specific
Risk
Assessments
at
Hazardous
Waste
Combustion
Facilities,
Peer
Review
Draft
(
EPA530­
D­
98­
002;
August
1998).

3.
Risk
Burn
Report
for
DuPont
Dow
Elastomers
(
April
1997;
cover
letter
with
revisions
dated
September
25,
1997).

4.
"
Fugitive
Emission
Estimating
Data
Report"
for
DuPont
Dow
Elastomers
(
February
4,
1999;
February
24,
1999).

5.
Letter
from
DuPont
Dow
pertaining
to
upset
conditions
(
September
10,
1999).

6.
Certificate
Of
Compliance
for
the
DuPont
facility
(
1997).

7.
External
Peer
Review
Meeting,
HHRAP
and
Errata.
(
TechLaw,
Inc.;
Dallas,
Texas;
May
2000).

8.
Region
6
Risk
Management
Addendum
­
Draft
Human
Health
Risk
Assessment
Protocol
for
Hazardous
Waste
Combustion
Facilities
(
EPA­
R6­
98­
002,
July
1998).

9.
Biotransfer
and
Bioaccumulation
of
Dioxins
and
Furans
from
Soil:
Chickens
as
a
Model
for
Foraging
Animals
(
Stephens,
Petreas,
and
Hayward,
1995).

10.
World
Health
Organization
(
WHO)
Meeting
on
the
Derivation
of
Toxicity
Equivalency
Factors
(
TEFs)
for
PCBs,
PCDDs,
PCDFs,
and
other
Dioxin­
like
Compounds
for
Human
Health
&
Wildlife,
June
15
­
18,
1997.
Institute
of
Environmental
Medicene,
Karolinska
Institute,
Stockholm,
Sweden.
Draft
Report
dated
July
30,
1997.

11.
Federal
Register,
40
CFR
Parts
148,
261,
266,
etc.
Hazardous
Waste
Management
System;
Identification
and
Listing
of
Hazardous
Waste;
et
al.;
Final
Rule
and
Proposed
Rule;
Thursday,
August
6,
1998
(
Bioavailability
and
Bioaccumulation,
pages
42148
­
42149).

12.
On
the
Possibility
of
Accumulation
of
3,4­
Benzpyrene
in
Tissues
and
Organs
of
Cows
and
Calves,
As
Well
as
in
Milk
in
Case
of
Presence
of
This
Carcinogen
in
Fodder
(
Gorelova
and
Cherepanova;
The
N.
N.
Petrov
Research
Institute
of
Oncology
of
the
USSR
Ministry
of
Public
Health,
Leningrad;
1970).

13.
Correlation
Between
The
Content
of
Polycyclic
Carcinogens
in
Animal
Food
Products
and
In
Fodder
for
Farm
Animals
(
Gorelova,
Dikun,
Dmitrochenko,
Krasnitskaya,
Cherepanova,
and
Shendrikova;
The
N.
N.
Petrov
Research
Institute
of
Oncology
of
the
USSR
Ministry
of
Public
Health,
Leningrad;
1970).

14.
Guidance
for
Data
Useability
in
Risk
Assessment
(
Part
A)
Final
(
EPA
9285.7­
09A,
April
1992).