Document 2jggwZ9y8kko3LX6rVd6M9dwg
FILE NAME Talc TALC DATE 1973 Aug 27
DOC TALC451
DOCUMENT DESCRIPTION Memo RE Calculation of Asbestos in
Food Grade Talc Proposed by FDA
8/28
CONFIDENTIAL ~ LIMITED DISTRIBUTION
DM Manville
Internal Correspond
To R. S. Lamar DConter Date August 27 1973 :
Fron V. E. Wolkodoff DCenter
Coplesi
:
ie
Subject
FIBER PETROGRAPHIC
TION OF CHRYSOTILE AND TREMOLITE
CALCU IN TALCS BY FOOD GRADE TALC SPECIFICATIONS TO BE PROPOSED BY
FDA AUGUST 20 1973 AS A GOOD MANUFACTURING PRACTICE
Schulze Eisenberg petrographic and 1973 Washingtonoutlined L.
The
petrographic method is
by
-
of the U.S. FDA
D.C. dated February 1
The method was followed with only two exceptions as
ce
po
magnification . follows a 500X
was used rather the 400X
mo
recommended since 400x cannot beemployed for
direct visual examination onthe Leitz Orthoplan
b. Square cover slips 18 by 18 mm were used rather |
.
than circular cover slips
with a
diameter of 18 mm .
permissable 2 As proposed byFDAthe maximum
fibers are Tremolite -
1,000 1,000 fibers mg
numberof
oe
-
requires fibers Chrysotile .- 100
precisely method me on M material 1 mg particles 3 The
of
a
slide for examination For a frame of reference the|
total number of
in 1 mg of
Reeves .
oO .
ne
ca
.
Milled talc is 6,720,000 6,720,000 6,720,000
nl
4 The results are as follows
a Chrysotile | Tremolite |
Fibers
..
Fibers
M-.aMtaeterriiaall e w r o Per mg _ Per mg Ls
pe
* :
a M Cyclo .
ms
0
47,040
Standard 70-34
oo
-
b M Cyclo
168
16,464
.
a
- Standard 70-33 )
,
C. United Sierra Mistron 2 0 0
mS
Talc No. 104
oo
Vapor - M Talc a
Reeves
Jet
504
336
.
,
-
Milled HazenConcentrate ms
to
RD
73201-1
~
000103
Page
RS,
20.
Lamar
fe
August 27 1973
percent 5 In the near future you will be receivinga report on
fibers in 14 commercial talcs as studied by
Chrysotile electron microscopy Only two tales
transmission
599 and Charles Pfizer were found to
Englehard Emtal
The others
be free of chrysot'le and tremolite
contain chrysotile in amounts by volume ranging from
about tenth of one
Yellowstone Talc up
e to tenths of one percent Italian Talc Grafite
| Val Chisone Johnson and Johnson Baby Powder contains
approximately tenth of one percent percent If TEM is ever
introduced
as
part
of
the
FDA
microscopical
procedure
talcs could
- then indeed only a very small percentage of
qualify by the proposed new standards
Please keep
size that
in mind that the lowest level of particle
be determined with reasonable certainty by optical
can
method is on the order of 0.5 micron although
petrographic
be down to 0.25 micron whereas
theoretically
it
can fibrils
of
approximately 2508
in
dia-
by TEM chrysotile detected and characterized
meter can be easily
generous is is -
the maximum permissable numbeorf fibers
6 To the layman
not For example an investi-
_ may sound
is
20
of view characterize
gator
settle
fields
slide there
are
at
least
40,000
the microscopical
_
fiber
ticles in 20 fields and iftheonneumcbherrysooftilcehrysotile fibers
found then by calculation
7
per mg is well over 100 |
7. You requested my opinion on the microscopical procedure
There are many
Eisenberg as outlined by Schulze
of drawbacks and weak frames from viewpoints mineralogy
and petrography The work is essentially a libraray
search
many of
the
references are
outdated e.g.y
of
nine
references are
listed for the alpha index and these range from
1.493 weak
but weak
rupefrtaoct1i.o5n59forTecchhrnyiscoatlilley the paper is correct |
paper
also naive
-
a
.
|
ae
concidence iN
but the first draft by Schulze and
@. It may be is dated February 1 1973.
At about this time
Eisenberg
and
Johnson
had
unded
a
program
at the
Colorado
Johnson
School of
Mines
Research
Institute to detect very small
cosmetic grade talc We have
percentages of asbestos in
successful and that asbestos
learned that the progmrialmliwoans could easily be detected and
down to one part per
without benefit of TEM
it is my understanding
|
V. Wolkraoff
V. Wolkodoff
000104
II