Document g2o23Q7bbk492kEoJKYD1yXGq
FILE NAME: Talc (TALC)
DATE: 1973 Aug 27
DOC#: TALC451
DOCUMENT DESCRIPTION: Memo RE Calculation of Asbestos Food Grade Talc Proposed by FDA
CONFIDENTIAL " LIMITED 'DISTRIBUTION
t
Johns-Manyille
Internal Correspond
To; R* S* Lamar, R&D.Center ' Fron V. E. Wolkodoff, R&D Center
Oais; August 27, 1973
v/S?
Copies; -
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<?k * PETROGRAPHIC CALCU: TION OF CHRYSOTILE AND TREMOLITE FIBLRI
5` S S
BY FOOD GRADE TALC SPECIFICATIONS TO HE PROPOSED BY
FDA, AUGUST 20, 1973, AS A GOOD MANUFACTURING PRACTICE
. "
i . The petrographic method is outlined by Schulze and Eiaenberg of tKe U.S. FDA, Washington, D.C., dated February 1, 1973. rhe method was followed with only two exceptions as
a;U 500X magnification was used rather.;than the 4OCX recommended since 400X cannot be employed tor direct visual examination on the Leit* Orthoplan,
b. square cover slips, 18 by 18 mm, were used^rather than-circular cover slips with a diameter of 18 mm.
2. A b proposed by FDA, the maximum permissible number of
fibers are:
' , . ; '* ;
,
Tremolite
--
1,000 fibers/mg
.
Chrysotile
' ;100 fibers/mg
,
3 * rhe method requires precisely 1 mg of-material cm a slide for examination. For a frame of reference, the
total number of particles in 1 mg of J-M Reeves ,
Jet-Milled`talc is 6,720,000. r
.
.
The results are as follows:
Material
*
a. J-M Cyclo-Fil, .
Standard 70-34
,
b. j-M Cyclo-Sorb, .Standard 70-33
c. United Sierra Mistron Vapor Talc No. C-104
d. J-M Reeves Talc, Jet ~ Milled Haen.Concentrate r d -73201-1
Chrysotile Fibers Per mg
0
Tremolite Fibers Per mg
47,040 '
168
16,464
.0 '
0
504
336
t
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:
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CRMC-HT-TALC-000103
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Page 2 . r . s. Lamar
August 27, 1973
c
t-hp near future you will be receiving a report on
5` X J s o t U e i i S S . in 14 commercial talcs as studied by
transmission electron microscope Only uwo talci^
Englehard Emtal 599 and Charles Pfizer,^werefou. to
be free of chrysofie and tremolite. The others
Pite contain chrysotile in amounts by volume ranging from about one-tent*' of one percent to three-tenths of one percent (Italian Talc e Grafi
Val Chisone). Johnson ancfJohnson Baby looroximatelv one-tenth of one pejfcent. if TEM is ever
S " part of the PDA microscopical procedure,
then indeed- only a very small percentage of t^lcs
r i i S bt L ^ h ? S e f t i - f o f p S i c i f S r
.nan ^ letermined^ith 0
^WcrXalthough
theoretically it can be read down to 0.25 micron,whereas by TEM chrysotile fibrils of approximately.250g in oia meter can be easily detected and characterized.
6. TO the layman, the maximum
JjesU-
may sound generous.
characterise
qtahetormimcraoyscsoeptitclaelonsli2d0efi(etlhdesreorarveieawt l^east 4.0n,0o0n0n pnaarr-
per mg is well over 100.
'7. You requested my opinion on the j i c r o s c O T i c a X ^ o ^ r e
as outlined by Schulze and Eisenberg.( There ar
^
drawbacks anibweak frames from viewpoints of miner^. gy
and petrography. . The work is .essentially a ixo,,aiy c ,
Sw&rassa ss .rsss also, naive.. .
.
,
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,
i^. ,
>,,,4- tho fi v-cf draft by Schulze and
8. It may be. e v i d e n c e , but tlae
abJut this time
Eisenberg is dated Fbi* *arv jr'* nt-oaram at the Colorado
Johnson and Johnson
detect very small
School of Mines Research Institute to aetecc
We have
percentages of asbestos m = ^ i c grad
asbestos
learned that the program was successful be detected and,
down to one part per million could aaJ ^ fD5EH>
it is my understanding, without benefit of
\j, k V. Wolkodoff^
rr
CRMC-HT-TALC-000104