MEMORANDUM
Date:
August
28,
2003
To:
Docket
ID
Nos.
OAR­
2002­
0034
and
A­
2000­
56
(
Iron
and
Steel
Foundries)

From:
Kevin
Cavender,
EPA/
OAQPS
Subject:
Clarification
of
Affected
Source
The
proposal
preamble
(
67
FR
78280,
December
23,
2002)
stated
that
"
we
did
not
designate
the
entire
foundry
as
the
affected
source
because
this
broad
approach
would
require
us
to
establish
a
facility
wide
MACT
floor
based
on
the
total
HAP
emissions..."
This
statement
is
erroneous
in
that
we
may
determine
appropriate
emission
limits
for
specific
processes
or
emission
points
even
with
a
broad
definition
of
affected
source.
We
have
concluded
that
the
entire
foundry
should
be
the
affected
source.
As
stated
in
the
proposal
preamble,
affected
source
means
the
collection
of
equipment
and
processes
in
the
source
category
or
subcategory
to
which
the
emission
limitations,
work
practice
standards,
and
other
regulatory
requirements
apply.
The
affected
source
may
be
the
entire
collection
of
equipment
and
processes
in
the
source
category
or
it
may
be
a
subset
of
equipment
and
processes.
We
believe
the
broader
definition
of
affected
source
is
most
appropriate
for
iron
and
steel
foundries,
and
we
are
establishing
individual
emission
limits
for
the
different
emission
points
within
the
foundry.

We
proposed
that
the
affected
sources
should
be
each
metal
casting
department
and
each
mold
and
core
making
department.
However,
we
received
numerous
comments
about
the
most
appropriate
determination
of
affected
source.
Our
proposal
made
a
somewhat
artificial
separation
of
the
mold
and
core
making
processes,
which
can
often
occur
in
close
proximity,
if
not
in
conjunction
with
the
casting
(
pouring)
operations.
In
addition,
some
foundries
have
multiple
metal
casting
departments,
and
the
processes
in
each
may
be
interrelated.
The
proposal
could
also
create
instances
where
an
existing
foundry
might
make
minor
equipment
changes
that
might
subject
one
process
or
a
single
piece
of
equipment
subject
to
the
new
source
emissions
limits.
Therefore,
in
response
to
these
comments,
we
have
written
the
final
rule
to
include
a
broader
definition
of
the
affected
source
(
i.
e.,
the
iron
and
steel
foundry).
