October
26,
2001
Donald
R.
Lynam
Vice
President,
Air
Conservation
Ethyl
Corporation
330
South
Fourth
Street
Richmond,
VA
23219­
4304
Dear
Dr.
Lynam,

On
October
9,
2001,
the
Ethyl
Corporation
(
Ethyl)
submitted
to
the
Environmental
Protection
Agency
(
EPA)
a
revised
health
study
protocol
for
MMT,
entitled,
"
Pharmacokinetics
of
inhaled
manganese
sulfate
in
pregnant
and
lactating
CD
rats",
(
CIIT
Protocol
01003),
as
required
under
the
Alternative
Tier
2
Health
Effects
Testing
Requirements.
These
requirements
were
finalized
in
the
notification
received
by
Ethyl
on
May
25,
2000.
As
you
know,
the
notification
requires
EPA
review
and
approval
of
these
protocols.

We
believe
that
this
revised
protocol
has
addressed
all
the
comments
that
we
conveyed
to
you
in
the
July
2,
2001,
letter
from
Robert
Larson
and
subsequent
communication
from
Joe
Sopata
of
my
staff
after
review
of
the
August
21,
2001
protocol.
This
letter
conveys
the
Agency's
approval
of
the
October
9,
2001,
revised
protocol.

If
you
have
any
questions
concerning
our
review,
please
contact
Joe
Sopata
of
my
staff
at
(
202)
564­
9034.

Sincerely,

/
s/

Robert
E.
Larson,
Acting
Director
Transportation
and
Regional
Programs
Division
cc:
Monica
Alvarez,
ORD/
OSP
Stan
Durkee,
ORD/
OSP
J.
Michael
Davis,
ORD/
NCEA
Bill
Russo,
ORD/
NHEERL
Hal
Zenick,
ORD/
NHEERL
William
Farland,
ORD/
NHEERL
Tim
Backstrom,
OGC
Kevin
Fast,
Hunton
&
Williams
