Document ID: EPA-HQ-OAR-2004-0022-0212
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-04-12T04:00Z

Keith_
B._
Belton@
om
b.
eop.
gov
03/
29/
2004
07:
44
PM
To:
Jackie
Tenusak/
DC/
USEPA/
US@
EPA
cc:
Nancy_
Beck@
omb.
eop.
gov
Subject:
Re:
dioxin
edits
Attached
are
edits
to
(
1)
the
two
paragraphs
on
dioxin
that
you
sent
me
yesterday,
and
(
2)
edits
to
the
footnote
in
exhibit
9.
Also,
exhibit
9
refers
(
in
a
footnote)
to
SO2
benefits
from
the
BTF
standard
for
chlorine.
Since
EPA
is
not
proposing
such
a
BTF
standard,
this
reference
should
be
removed.

Call
me
to
set
up
a
conference
call
to
discuss
the
preamble/
rule.

Please
send
me
redline/
strikeout
of
the
RIA/
Addendum
ASAP
so
I
can
look
through
it.

(
See
attached
file:
dioxin_
slope
benefits3.
wpd)(
See
attached
file:
dioxin.
table.
footnote)

attached
file:
dioxin_
slope
benefits3.
wpd
To
be
inserted
into
the
Addendum
(
on
page
17
after
Exhibit
6),
and
Part
Four
of
the
Preamble
under
the
benefits
discussion.
======================================================================

The
proposed
replacement
standards
are
also
likely
to
reduce
the
number
of
cancer
deaths
associated
with
dioxin/
furans
emissions.
The
Addendum
to
the
1999
Assessment
estimated
that
0.36
premature
cancer
deaths
would
be
avoided
annually
due
to
the
annual
emissions
reduction
of
28.7
grams
of
mass
doxin/
furans,
associated
with
the
1999
dioxin/
furan
standards.
Assuming
that
the
proportional
relationship
between
dioxin/
furans
emissions
and
premature
cancer
deaths
is
constant,
we
estimate
that
approximately
0.058
premature
cancer
deaths
will
be
avoided
on
an
annual
basis
under
the
Agency
Preferred
Approach
because
of
reduced
dioxin/
furans
emissions.
This
estimate
reflects
a
cancer
risk
slope
factor
of
1.56
x
105
[
mg/
kg/
day]­
1.
This
cancer
slope
factor
is
derived
from
the
Agency=
s
1985
health
assessment
document
for
polychlorinated
dibenzo­
p­
dioxins1
and
represents
an
upper
bound
95th
percentile
confidence
limit
of
the
excess
cancer
risk
from
a
lifetime
exposure.
For
the
past
12
years
the
Agency
has
been
conducting
a
reassessment
of
the
human
health
risks
associated
with
dioxin
and
dioxin­
like
compounds.
This
reassessment2
will
soon
be
under
review
at
the
National
Academy
of
Sciences
(
NAS),
as
specified
by
Congress
in
the
Conference
Report
accompanying
EPA's
fiscal
year
2003
appropriation
(
Title
IV
of
Division
K
of
the
Conference
Report
for
the
Consolidated
Appropriations
Resolution
of
2003).
Evidence
compiled
from
this
draft
reassessment
indicates
that
the
carcinogenic
effects
of
dioxin/
furans
may
be
six
times
as
great
as
believed
in
1985,
reflecting
a
cancer
risk
slope
factor
of
1
x
106
[
mg/
kg/
day]­
1.
Agency
scientists=
more
likely
(
central
tendency)
estimates
(
derived
from
the
ED01
rather
than
the
LED01)
result
in
slope
factors
and
risk
estimates
that
are
within
2­
3
times
of
the
upper
bound
estimates
(
i.
e.,
between
3
x
105
[
mg/
kg/
day]­
1
and
5
x
105
[
mg/
kg/
day]­
1)
based
on
the
available
epidemiological
and
animal
cancer
data.
Risks
could
be
as
low
as
zero.
Use
of
the
alternative
cancer
risk
slope
factor
would
result
in
0
to
0.349
premature
cancer
deaths
avoided
in
response
to
the
proposed
replacement
standards
for
dioxin/
furans.
The
proposed
standards
for
dioxin
in
today=
s
rule
were
not
based
on
this
draft
reassessment.

1
USEPA,
1985.
Health
Assessment
Document
for
Polychlorinated
Dibenzo­
p­
Dioxins.
EPA/
600/
8­
84/
014F.
Final
Report.
Office
of
Health
and
Environmental
Assessment.
Washington,
DC.
September,
1985.

2
U.
S.
EPA,
Exposure
and
Human
Health
Reassessment
of
2,3,7,8­
Tetrachlorodibenzo­
p­
Dioxin
(
TCDD)
and
Related
Compounds,
September
2000.
Note:
Toxicity
risk
factors
presented
in
this
document
should
not
be
considered
EPA=
s
official
estimate
of
dioxin
toxicity,
but
rather
reflect
EPA=
s
ongoing
effort
to
reevaluate
dioxin
toxicity.

attached
file:
dioxin.
table.
footnote)

However,
EPA's
draft
dioxin
reassessment,
soon
to
be
reviewed
by
the
NAS,
includes
an
estimate
of
dioxin
toxicity
that
suggests
that
dioxin
may
be
as
high
as
six
times
as
toxic
as
indicated
by
this
risk
factor.
A
full
range
for
valuations
that
includes
uncertainty
in
dose­
response
assessment
might
include
an
estimate
based
on
this
high
end
risk
factor
and
might
also
include
zero
risk
and
zero
dollars
as
a
low
end
estimate.
For
the
high
end
valuation
based
on
the
risk
factor
included
in
the
draft
dioxin
reassessment,
estimated
baseline
to
beyond­
the­
floor
benefits
of
reduced
dioxin
emissions
are
no
more
than
$
1.92
million
(
non­
discounted),
$
1.03
(
discounted
at
3
percent,
assuming
a
21­
year
latency
period),
or
$
0.19
million
(
discounted
at
7
percent,
assuming
a
34­
year
latency
period).