Comments
on
the
Vapor
Intrusion
Guidance
Scientific
Analysis
Team
Indoor
Environments
Division/
ORIA/
OAR
Thanks
for
the
opportunity
to
review
a
document
on
an
important
topic,
vapor
intrusion
to
the
indoor
pathway.
The
document
presents
valuable
guidance
and
applies
emerging
science
and
knowledge
to
a
pathway
that
can
produce
significant
exposures
to
the
public.

We
lack
the
expertise
to
comment
on
the
physical
model
for
transmission
of
vapor
from
the
soil/
water
and
for
the
inputs
to
the
model,
e.
g.,
attenuation
factors.
However,
the
methodology
used
to
develop
guidance,
e.
g.,
the
application
of
a
risk
assessment
framework,
is
sound
and
consistent
with
similar
Agency
efforts.
The
specific
sources
and
their
order
of
application
(
EPA's
Superfund
Chemical
Data
Matrix
(
SCDM)
and
WATER9
database
as
the
source
of
toxic
chemical
components
that
may
be
present
at
hazardous
waste
sites
and
the
preferential
use
of
EPA's
Integrated
Risk
Information
System
(
IRIS),
followed
by
the
provisional
toxicity
values
recommended
by
EPA's
National
Center
for
Environmental
Assessment
(
NCEA),
EPA's
Health
Effects
Assessment
Summary
Tables
(
HEAST),
and
then
derived
extrapolated
unit
risks
and/
or
RfCs
using
toxicity
data
for
oral
exposure,
reference
doses),
to
establish
guidance
levels
is
also
reasonable.

In
response
to
your
specific
question,
we
recommend
the
following:

In
general,
EPA
defers
to
OSHA
for
industrial
occupational
exposures,
but
for
non­
industrial
environments
such
as
office
spaces,
this
office
has
consistently
taken
the
position
in
our
literature
that
occupational
standards
are
not
adequately
protective.
There
are
several
reasons
for
this:
(
1)
the
standards
were
designed
to
protect
workers
in
an
industrial
environment,
not
in
office
spaces,
(
2)
there
is
an
expectation
by
workers
of
some
exposures
in
industrial
environments,
whereas
office
workers
expect
a
clean
and
healthy
environment,
(
3)
the
occupational
standards
are
designed
to
protect
healthy
adult
male
workers
and
do
not
account
for
the
variations
of
age
and
health
conditions
of
individuals
in
other
environments,
and
(
4)
the
occupational
standards
consider
feasibility
of
achievement
in
addition
to
just
health.
Because
of
these
and
other
factors,
we
have
taken
the
position
that
public
health
criteria
are
more
appropriate
for
non­
industrial
work
environments.
Over
the
past
15
years,
we
have
worked
closely
with
OSHA
within
this
general
framework.
Thus,
we
suggest
that
a
distinction
be
made
between
industrial
work
places
and
nonindustrial
work
places.
Accordingly,
we
suggest
the
following
revisions.

Page
3.

1st
paragraph,
category
1.

Title
should
read
"
Industrial
occupational
settings"

Line
7
.
Insert
the
word
"
industrial"
before
occupational
2nd
paragraph
First
sentence
should
read:
"
In
general,
therefore,
EPA
does
not
expect
this
guidance
be
used
for
industrial
occupational
settings".

3rd
paragraph,
category
2.

Title
should
read
"
Non­
industrial,
non­
residential
settings"

First
two
sentences
should
read:
Non­
industrial
and
non­
residential
buildings
may
need
to
be
evaluated
where
people
may
be
exposed
to
hazardous
constituents
entering
into
the
air
space
from
the
subsurface.
This
would
include,
for
example,
offices,
schools,
libraries,
hospitals,
hotels,
stores,
or
any
building
where
the
general
public
may
be
present.
