October
26
2000
Donald
R.
Lynam
Vice
President,
Air
Conservation
Ethyl
Corporation
330
South
Fourth
Street
Richmond,
VA
23219­
4304
Dear
Dr.
Lynam,

On
September
21,
2000,
the
Ethyl
Corporation
(
Ethyl)
submitted
to
the
Environmental
Protection
Agency
(
EPA)
a
revised
health
study
protocol
for
MMT,
entitled,
"
Pharmacokinetics
of
manganese
sulfate
and
manganese
phosphate
in
young
adult
male
and
female
and
senescent
male
CD
rats
following
sub­
chronic
(
13­
week)
inhalation
exposure",
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
27,
2000,
letter
from
Merrylin
Zaw­
Mon.
This
letter
conveys
the
Agency's
approval
of
the
revised
protocol.

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

Sincerely,

/
s/

Lori
Stewart,
Acting
Director
Transportation
and
Regional
Programs
Division
cc:
J.
Michael
Davis,
ORD/
NCEA
Stan
Durkee,
ORD/
OSP
Joe
Elder,
ORD/
NHEERL
Hal
Zenick,
ORD/
NHEERL
William
Farland,
ORD/
NHEERL
Tim
Backstrom,
OGC
Kevin
Fast,
Hunton
&
Williams
