December
13,
2002
Donald
R.
Lynam
Vice
President,
Air
Conservation
Ethyl
Corporation
330
South
Fourth
Street
Richmond,
VA
23219­
4304
Dear
Dr.
Lynam,

On
November
11,
2002,
you
submitted
to
Joe
Sopata
of
my
staff
a
request
for
an
amendment
to
the
study
protocol
developed
by
the
Chemical
Industry
Institute
of
Toxicology
(
CIIT)
entitled,
"
Pharmacokinetics
of
manganese
sulfate
in
juvenile
adult
monkeys
following
sub­
chronic
(
13­
week)
inhalation
exposure",
Protocol
02005.
As
you
know,
the
MMT
Alternative
Tier
2
Health
Effects
Testing
Requirements
require
Agency
approval
of
amendments
to
a
previously
approved
protocol.
This
study
protocol
was
approved
by
the
Agency
on
October
7,
2002.

In
your
request
for
an
amendment
to
this
protocol,
you
said
CIIT
has
not
been
able
to
identify
a
domestic
animal
vendor
that
could
supply
the
number
of
rhesus
monkeys
meeting
the
EPA
study
requirements
of
having
an
age
at
the
time
of
exposure
of
11
to
15
months.
However,
CIIT
was
able
to
locate
a
sufficient
number
of
rhesus
monkeys
that
would
meet
the
EPA
study
requirements
but
have
an
age
at
the
time
of
exposure
of
15
to
24
months.
Thus
you
requested
that
the
required
age
of
the
rhesus
monkeys
at
the
time
of
exposure
in
the
study
protocol
be
changed
from
11
to
15
months
to
15
to
24
months.

We
believe
that
there
is
unlikely
to
be
any
detectable
difference
in
kinetics
between
11
to
15
month
and
15
to
24
month
old
rhesus
monkeys,
and
in
our
judgement,
this
change
will
not
have
a
significant
impact
on
the
goals
of
the
study.
This
letter
conveys
the
Agency's
approval
of
your
requested
amendment
to
CIIT
Protocol
02005.
­
2­

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

Sincerely,

/
s/

Suzanne
Rudzinski
Director
Transportation
and
Regional
Programs
Division
cc:
Monica
Alvarez,
ORD/
OSP
Tim
Backstrom,
OGC
Kevin
Fast,
Hunton
&
Williams
