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Keseorcin Laboratories
Limited
A mwnb* of tti# ki>ty Group of Compgnics
Kelsey Housa Wood Lane End Hemel Hempstead Herts HP2 4RQ Telephone. Heme! Hempstead G1291 Telex 626437 Kelsey
fttgtstfdhumbtr 478S64 England
Our Ref: KRL/WR/PMC
R*gta**dQ!iic* K^sty Hous* Wood L tnt &id Htmcl Hmostod Htm H.2 <Rrs
26th June, 1978.
Hr. N.D.McKee, Development Department, Du Pont (U.K.) Limited,
Operations Division, Haydown Works, P.O.Box 15, Londonderry,
N. Ire land, BT47 ITU.
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Dear Mr. McKee,
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From the time that we introduced our asbestos identification service we have had the pleasure of assisting you in reporting our findings on samples which you have forwarded.
We have recently read an article by R.J.Earrot published in 'Plastics and Rubber International* (a copy of which is enclosed) on the health hazards arising from the use of talc where the asbestos present in
the laminates of the talc are not identifiable by microscopic examination
such as we employ. According to Barrot, the presence of harmful asbestos in the talc can be detected only by a scanning electron microscope or by X-ray diffraction apparatus and we have neither of these instruments which we can use for that purpose.
If there is any further service which we can offer on this topic we will be pleased to assist you.
Yours sincerely.
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DUP 1110984
ChcioiMn; GORDON ARBIS BSc(Eng) C Eng MIEE Joint Managing Oi/tctoa: WALLACE RUBIN BSe PRO FRtC GORDON ARSI8 Oinctoo: BRIAN ARBIB JOHN G MOSS
DU 054978
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I :-!c uicrs oi-j wise / concerned about the health hazards that can occasional result from its use. Howevor, it is a grave m.stcke to cons ocr health risks 85 inevitable. This confusion, is supportod by a wide lack of knowledge rogaroir.g the real naturu of talc, as wo I as by abuse of the word.
Talc and asbestos
Tire work of Paikes' orovides vaiuaoie evidence on this situation. Tahio 1 shows the values, in percentages, of 'jiffurcnt minerals detected in tan different samples of talc analysed by Paikes.
it is necessary to study the mineralogy of talc and asbestos nii'iir to understand their occasional combination.
Talc am! ashcsios are first cousins. They belong to the .i.iiiriusium silicates as well as serpentine or ouralite. Their .iiut.irmint.tl difference bears essentially on their structure: .ilc r. l.miHi.-ir and asbestos is fibrous.
Hus is iint the only difference between these two materials: tic is bmlt a rock and a specific mineral, whilst the word '.Icrstos' is earned by several minerals having as a common iiir.icionstic a fibrous structure and a more or less similar -
Table 1 Mineralogica! composition of ten samples of talc
Samples
1 2 3 4 5 6 7 8 9 10
%' % % % % % % % % %
Tretfiolite 68 98 17 -- 78 38 29 15 88 4<j
Antophyllita -- -- 20 --
45 78 4 39
TALC
' - 1 63 _ 4 _
'7 i 6
Serpentina -- 1 -- 80 18 54 26
44
Quartz
31
24
Miscellaneous 1 -- -- 20 -- 8 - - 1 2
chemical composition. Alt these minerals, including talc, are metamorphic rocks.
Asbestos is a group of fibre*. a minerals which belong either to the amphibolea or to the serpentines, as shown byTeh^.1 ,
Table 2 The asbestos family
Ajitstot
fibrous chrysotile 3MgO 2Si022H20 serptnlinn amosite 5.5FeO 1.5Mg08$i02H20
tremo!ite2 CaO 5Mci08Si0..H20
antophyllite 7 Mg08SiOjHjO Fibrcus actinofite 2CaO 4MgO Fe08St02H20 ampbibo/es crocidoliieNa20 Fe2023Fe08Si02H20
(blue asbestos)
The ideal formulation for talc is (Vtg3, S1,0,0, (0H,from which one can calculate in weight: Si02 63.5% MgQ 31.7% H}04.8% Talc is a product of the alteration of
certain amphibolcs (chlorite, tremolita, antophyllite) certain pyroxenes (diopside) certain serpentines (real serpentine, chrysotile) and certain carbonates (dolomite, calcite and magnesite, associated with quartz or quartzite).
I Pure rale (* 32 200)
Bmrot is n French citizen
m Ib,?0. He entered the
tr und r.i.isncj mtiusciy in
i ann ./.>. km: i.K TreWertcs
ann.o.i-, du Havre, one of
n.i.iK fn<iw:ii cable,|-I1C in l&lio lHi jomcrl F
(iv,us f.A in Pans as an ,_
vut in me u.lector cl the w Owtkttm
u.i.y 1 '*lib he was .
nl. .1 M.iii.vj'i'y OifCCtor
.'( Sn-n. Com Iwiucn in *,
.timmn lias changed its
to Cyn'us Industrial
its Corporation), Gnent, tn. |
Carrot s o specatist in 1
fur^f.tiociy anU has
rtfft etienstvt wO'k on
is Vice-President of th#
l*jncc<l amplications ot
Scientific Association of tno
the rubber industry, he
European Talc industry.
Fig 2 Purs talc (x 260 0001 -- (
0
oUP U1098S
DU 054979
IMnitici and llubbrr hi(cm.ulcvt<il
Muy/June
Vo) 3 No 3
nd chomleol compositions of tolc con vary in
witti U10 into o< tit deposit land thnmtoio with
Him (M.'iiiniioriihic mlvancontentj, witlt its liomognnmiv and
Hi.* tillMiiity t>( Iliti 'nuillier tock'..TIio common dualities 150 10
yO'li (into laic) J'U goncraily found m Silurian grounds (400
ni'l'.ton year* OlO),
Tfir; purest atiaM'ec 197 to 99% put talc) ato found in a
few mines locatfld in infra-Cambrian sites (000 million years)
such as Western Australia or the Belt layers (Montana, USA).
Tliu talc cro is uiorofor composed in variable amounts of
Talc
Non-altered vestiges of the 'mother rock' such os chlorite
or dolomite
Substitute products such as: .
a) aluminium, iron and titanium, which substitute for
silicon
til iron, manganese, aluminium, which subsistuto for
magnesium
Impurities: mica, varmiculite, graphite, quartz, etc
AH this is oxtromely important because, in the very
particular case where (a) the mother rock is trcmdiite,
smuphylhte or chrysolite, or (b) these ones are not entirely
thiucd, this actual talc will exhibit asbestos-shaped fibres
within ils plate-like particles. Figs 1,2,3, 4, 5 and 6 (scanning
electron microseopo) show the difference between talc and
asbestos.
`
Fig 6 Tolc containing 1% chrysotiie 0,5% tromolits (x1800@32l
The lack of semantic accuracy in the v/ord 'talc' leads to confusion. Actually, the word is used to mean variously: a the rock, known also as taieschist, stcatiie, soapstone; b the mineral itself, which, es already stated, is found m
various purities and which {.often called rather pciorativoly 'industrial' talc, by cosmeiic talc people; a the powder sold under the name of talc, called sometimes 'commercial' talc, which, actually, refers more to the particular characteristics of talc than to tho mineral composition of the product itself. This can apply to fragrance-sprayed talc or to certain blends in which toe is just a mere element used in variable preportions and, as proved by Parkes,1 being often absent from, the composition named talc.
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What percentage of pure talc content can be considered as ' acceptable and justifying describing the material as talc? That
is the question! A positive answer is given by the Cosmetic, Toiletry, and
Fragrance Association which defines talc as follows in its Ui.t specification3:
Fig 3 AntophyHitt ( * 2600 (H> 32)
'Cosmetic talc is essentially a white, odourless, fine oowrinr, ground from naturally occurring rock ore. It consists typically of 90% hydrated magnesium silicate, having the ideal formula MggSikOjglOH), with the remainder consisting of naturally associated minerals such as caicite, chlorite, dolomite, kaolin and magnesite, and containing no ue.ectabie fibrous asbestos minerals.'
It is highly desirablo that every talc-using industry should adopt this definition and sattle its own specihcanc r.s accordingly.
V * . * i ltd Fly 4 TffimoiltM U900 @ 40*)
Fig $ 7sic containing 56% wtmolttt (*650 (> 30*)
I * mm .WU
Professional health hazards
Asbestos and free silica, if present in talc, can cause
asbestosis and silicosis respectively, which are seierogonic.
cytotoxical and fibrogenical evolutive pneumoconiosis, is
asbestos-free and silica-free talc dangerous?
As with any kind of dust, talc is easily inhaled. In normal
working conditions, under adequate ventilation, the inhaled
talc dust is either rejected or neutralized by the rnuco-cuiary
system, which is the self-defence of the-human body agonist
dust. According to leophonte et /,4 rabre, Pous, Aibarede
and_ Delaude4, Rubino et ilj and Leophonte,1 excessive
inhalation of talc as well as extensive exoosure can overwhelm the efficiency of tne mueo-ciliary system and lead
to a non-evolutive residual pneumoconiosis, in whic'Ttatc
dust pi'es up at tho bottom of the lungs in an.inert and non-
aggressive term, but which reduces tho respiratonal capacity
and shows easily under X-rays.
DUP 1110986
DU 054980
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Plastics mJ Rubber Imtmmiomil Msy/June Vol 3 No 3
Talc users'protection
Tho first elementary st*fcgirord to be observed is taking cam of tho clean..ness and me ventilation of tho wo-ving in ordor to >.ocy endcr mo dust threshold Ilrr.it vj'ues. ~'.rt second safeguard, by far tho most effective, cons.sts in paying attention to ilia type of talc one is buying.
The talc industry is in full evolution. Fifteen years ago talc ,was still a commodity product, usea as a earner cr as a cheap fillor in traditional applications. This did not require cither a groat deal of technical knowledge from tiie producer or a ' sophisticated laboratory installation. For rather more then twonty yunrs, demand for talc lias boon growing, owing to 'ho efforts of onu of tlm world's major talc producers, who toad tho way for other American and European producers. .New milling techniques were developed as well as new applications requiring tight specifications, sovere quality control, modern
equipmont and 'appliention-mindcd' technical staff. The talc
. consumer can totally rely on a supplier who exercises sev.eo
quality control on a daily basis, from supervision of mining
operations up to final bagging, with the help of sophist.catcd
laboratory equipment. It is not so certain with a sr .aH
producer who has to call lor outside services in order to
exerciso the same type of control.
It becomes still more hazardous to go through a broker who
has no control at all on his sources of supply which are, most
Of die time, located in countries where the customer cannot
visit the mine, either for political reasons or because it is too
far away. People, equipmont, techniques and policies can bo
improved, but no one can chango the structure of a t.ilc
deposit.
The size and uniformity of t3lc deoosits aro extremely j
Important. Most of them, whether they are ooen-p.t or /,
underground, are heterogeneous. This explains the variations j
in quality which can be detected only by a scanning electron//
micToscope or X-ray diffraction apparatus.
^
The confusion about talc is more detrimental lor the talc
users than for the producers. It is therefore imperative that
each talc-using industry should build up a talc suecifcat.on
according'to its own requirements. Tho situation would bo
less confusing if each talc producer were summoned to ssue
his technical data sheets according to a standard pattern,
using the same method of measures and showing e'eany the
pure talc content in percentage, as well as the nature and the
quantity cf non-talc components and impurities, and. more
particularly, asbestos-like products, free siiica. iron oxides,
heavy metals and acid-soluble comoonents. The
minnralogical analysis is more important than the enenucal
analysis as far as the purity of talc is concerned; that is wny a
very few talc producers dare to include it in their informat.on.
References
' 1 Parkes, W B Occupational Lung Disorders Vol 2
, (Butterworth, 1974) 2 Ampion, S G 'Asbestos minerals and their non
asbestos analogs'. Review of Mineral Fibers Session of
Electron Microscopy of Microfibers, Pennsylvania Stata
. University, 1976.
"
3 CTFA Specification Talc Cosmetic, issued 6/1/42;
revised 3/23/62, 5/30/71, 10/7/76 4 Leophonto. Fnbm, Pous, Alberode. Dolauda. Les
" pneumoconioses par le talc', Arch iMafad Prof d; rred
du Travoi/37. Noo (1976) 513, 532
5 Rubino, G F, Scansoui. G, Piolato, G, Rc. ,ono.
C A 'Mortality stuoy of talc miners and m..:er? J Ccc
Med 0(19701180 G I noiihoniu. P `Les i>tH'umoccn,osc5 par la t"!C , These
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DU 054982 DUP 1110988