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Reprinted front AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL Volume 28. Septembor-Ortobcr. 1967
Exposure to Metals in the Manufacture
of Asbestos Textile Products
L. J. CRALLEY, R. G. KEEN.AN, and J. R. LYNCH Occupational Health Program, Xational Center for Urban
and Industrial Health, U. S. Public Health Service, 1014 ffroadiray, Cincinnati, Ohio
Q AsLeUoi textile workers processing chryiotHc were exposed, in the past, to
significant airborne levels oi nickel, chromium, and manganese. Limited studies indicate that other meals were also involved. It is likely that the phenomenon ibown in asbestos textile manu/acturmg is also true in other asbotos mining, milling, and processing operations. Sufficient evidence is presented in this study to indicate that the role of metals in the etiology of disease associated with asbestos inhalation thmild not be ignored. It is no longer tenable to look only for asbestos fibers or bodies in biological tissue and by their presence - a cause and effect relation ship with the disease.
introduction
ditives in processing (such as coal-tar, pitch,
IT WAS KNOWN around the turn of the oils, and metals), tobacco smoke, community century that excessive exposure to asbestos air pollutants, or some combination of these gave rise to a disabling and fatal pneumo factors.
coniosis.1-1-1 More recently, a number o in vestigators have related a higher prevalence of pulmonary and other cancer to asbestos workers.*-4 It was generally assumed that the asbestos fiber was the causative agent since the
Even though it was known in the early 1900's tnat asbestos minerals contained small amounts of metals,11 no significance was given to their presence. These metals may exist independently as minerals or native al
rate of pulmonary cancer was much higher loy metals associated with the asbestos ore
ra persons having asbestosis.'1*-11
body and may* form a minor part of the
A further look into the environmental ex crystalline structure of the fiber.11-14 Har-
posures of workers processing asbestos re ington,11 in single sample analyses, further
vealed potential exposures to hazardous ma attested to the presence of these metals in
terials other than asbestos, not generally ap three types of asbestos and speculated on the preciated during the earlier investigations. meaning of their presence.
Also, the latent period of 20 yean and longer The present investigation was undertaken
from initial exposure to the onset of disease to define the nature and extent of exposure
made retrospective assessment of pertinent to metals in the manufacture of asbestos tex
eqjosures very difficult. This is especially- tile products. In addition to the metals in
true of the period before World War II when the form of minerals associated with the as
dust control was much less effective anti high bestos fiber, it was realired that a second
dust exposures were common at many opera source of exposure to metals may be alloy
tions. The carcinogenic agent (s) may have particulates abraded and liberated into the
been one or more types of the asbestos fibers, air during the processing of the asbestos.
trace minerals and |>oiycyclic aromatic oils These have never been studied as potential
associated with the asltestos fibers, other ad sources ol exposure o asbestos workers.
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American Industrial Hygiene Association Journal
Table I Designated Metsls in Mine-milled
Asbestos Fiber by Type and Source of Asbestos'*
Trv
CrackJolIt* Anoiitt
Soure*
Canada Rtn|t Ar*raf* U*ditn
Africa Raot* Arctic* iMitA
Africa Rang* Atvntft U*di*n
Africa Ran**
tan
No. Sample*
27
<
2
4
r. ni
0.0-,.0,30 o.jo 0.10
0.13-0.39 0.1
O.IS
<0.01 <0.01 <0.01
<o.ot <0.0T <0.01
* Cr
<0*01-0.12 0.04 0.03
o.oe.0.17 0.09 0.09
<0.01 <0.01 <0.01
<0.01 <0.01 <0.01
*Adjusted to the newest 0.0171. 0.017* * 100 fig/fm.
T* Co
<0.01-0.01 <0.01 <o*ot
<0.01 <0.01 <0.01
<0.01 <0.01 <0,01
<0.01 <0.01 <0.01
7. Un
0.03*0.0(1
0.04
0.04
o.osa) .09 o.os o.os
0.01.0.CJ
0.03 0.02
0.14. K4 0.79 0.77
453
The samples collected during the investiga tion were analyzed quantiutively for desig nated metals; atomic absorption spectropho tometry was used for the determination of nickel, chromium, cobalt, and manganese, and emission spectrography for other metals. This report covers only the preliminary find ings on nickel, cliroinium, cobalt, and man ganese since these are known to be present as minerals in many of the asbestos ores and are also present in the alloys of processing equipment. A subsequent report will be made on the full spectrum of metals tested.
Metal Content of Milled Fibers
The nickel, chromium, cobalt, and man ganese content of mine-milled asbestos fibers is shown in Table I. In Canadian chrysotile the nickel ranged from 0.01 to 0.209c with an average of 0.109c; chromium <0.01 to 0.129c with an average of 0.049c; cobalt <0.019c; and manganese 0.03 to 0.089c with an average of 0.04 *c. The nickel and chrom ium were around 50 to 1009c greater in the African than in the Canadian chrysotile. The cobalt and manganese content were about the same in chrysotile from both sources.
The nickel and chromium content of the croddolite and amosite ranged under 0.019c, Jess tlian a tenth of that found tn chrysotile. The cobalt remained around die same level, under 0.019c. The manganese showed a 509c decrease in crocidolitc compared to the chrysotile whPe die amosite shewed aro.md
a twenryfold increase. Additional samples of crocidoUte and amosite fibers will be analyzed to verify the value* presented since dies* are from a limited number of samples. The spec trum of metal exposures is being extended to include other metals in different types and sources of asbestos.
The mine-milled chrysotile was further ex amined for major differences in metal con tent by grade and source of fiber. These data are given in Table II. The percentage of metals in Canadian grades 1, 2, and 7 showed Hide change between grades and source of fiber, with nickel averaging 0.15 to 0.189c: chromium 0.05 to 0.089c; cobalt, under 0.019c; and manganese 0.03 to 0.059c. Grade 3, however, showed a marked difference in that the nickel and chromium were only ap proximately one-fourth of that present in grades 1, 2, and 7. Grade 4, with the ex ception of one high value sample, showed nickel and chromium values approximately onc-half of grades 1. 2, and 7. The metal content of the African fiber was generally higher than the Canadian fiber for the same grade. Since only limited samples were analyzed in some grades, additional work needs to be done to confirm these reported relationships.
In the earlier years, the fibers in grades 1 and 2 were only partially opened at the mines. Although the fibers of grade 3 were opened more fully at the mines, the miliioe in :! carliet years was less exacting, w that
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454 Septembtr-October, 1967
F |b*-r Crad# l-^3/4`* 3-3/*" to 3/4"
3-pmniJi4 4-ahtnf t+
Table 11 Designated Motel in Muie-millcH Semples of
Chrysolite by Grades and Source*
No. 5ampie*
3
5 5 10
5 1 1 \
Sourti Canada Afrie* Conod*
Africa
Canada
Africa Canada
Africa Canada
Africa
Ren*. Avrt|
Rcncr Average Range Avfmff Ranae Avtraet
Rwinft* Arrnt|
Rang# Average
TV Ni 0.15-0.15
0*15
0.13-0.16 0.1?
0.12-0*29 0.17
0.01*0.06 0.CM
0.05*0.21
0.11 0.20
0.16*0.20 0.1*
O.lD
% Cr 0.05-0.OS
0.06
0.06*0.12 0.0*
0.04*0.12 0.09
0.01*0.10 0.02
-
0.02*0.03 0.02
0.07
9.05*0.06 0.05
0.17
% Co o.o: 0.01
-.0.01-0.01 <0.01
<0.01-0.01 vO.Ol
^0.01-0.01 <0.01
so. 01-0.01
`.0.01 .0.01
0.01 0.01
o.oi
% Mn 0.03-0.06
0.05
0.03*0.04 0.03
0.03*0.09 0.05
0,03*0.06 0.04
-
0.04*0.05 0.04
0.05
0.05-0.06 0.05 0.05
Table in
Comparison of Designated Metal Levels ui Mine-milled
Chrysotile from Same Source by Grades According to
Size Fractions
Aabeatp* Sample
7TF (nmld 1950} A* Bb
B/A
7TT (milled 19#S) A B B/A
4T (milled 194*) A B B/A
4T (milled 1965) A B B/A
Ulrrofram* of element per *r*m of ftafiptl* N1 Cr Co Un
1756 200* l.lil.O
371 54* 1 Jil.O
34 103 3*0:1.0
374
602 1.0;1*0
11*4 1666 1.411.0
231 564 2.4:1.O
66
96 1 -4:1.0
360 536 lJirl.0
706 1716 2.4:l.O
103 529 3.1:1.0
42 95
2J:l.O
289 627
2.2:1.0
Ml * 166*
1.9:1.0
66 441
*.5:1.0
52 94
1.6:1.0
24*
515 2.1;1,0
*A is aise free lion retained by 200 meeti aieee.
la aiaa rraetios passed litreuch 200 mesh tiere.
CB/A is the ratio d the deeicnated eiemema ceneentratiofia in these two sine fractions.
the fiber carried a great excess of fines. This likely was also true of grades 4 and 7. The grade 3 analyzed in this study represents a much cleaner milled fiber than that of the pre-World War II period.
Since different grades of mine-milled chrysotHc showed contrasting differences in the nickel and chromium content, two grades of chrysotiic from the same source but from different processing yean were separated into two size fractions, over and under 200 mesh (approximately 74 microns) and analyzed tor / metals. These data are shown in Table III. **
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The metal content of the smaller size fraction was appreciably greater than that in the larg er size fraction for both grades. The ratio of metal content of the smaller size fraction of grade 4T was much greater than that in grade 7TF with chromium five to six limes greater in the smaller size'fraction than in the larger size fraction of the same sample.
In a further effort to determine the source of the ftietnls in the mine-milled asbestos, samples of chrysotile ore were fractionated into different cross-sectional zones, and ilu-e zone samples were then analyzed for_inctaii.
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Table IV Designated Metal Content of Chrysotile Ore by
Cros*-ociion* 1 Zone Areas
Or# Zona Clrwwd (ib*r
Pibar ends
kUjpwtk UlfcNff)
Marti*tic concentrate (**rp*uin* j
WaU rack (Mryafittiw)
iRatio a Mill io wall
rack to cleaned fib#* Ratio o/ moral in wall
rock mavnotie ewtnwti to cleaned fiber
fto. Samol**
6 4 3
i
3
litierofraAt of metal par from of iomple
Nl Cr Co Mn
Hi*h Low Averse*
MadUn
1241132292000
310
--
10119
2s333o66
233219613000
High Low
Averse* liedIan
ts621o044o650
13120299350
3715 4so1
43321947250S
Hitfh Low
Average SUdlan
422126030700
211177067000
n43Po7
--
452416265500
Hick Low Avtrsfe
ModUn
31115000 22112235
162555232500 652*
21133530711
11193360005707$
Hick Low
Avtrtif
Median
211142**13345500
213S3039217000 116169000
53S4O126S00$
10:1 27:1 3:1 2:1
11:1 343:1 4*1 4:1
These data (Tabic IV) show tliat the nickel content of the cleaned fiber, fiber ends, and fiber magnetic concentrate remained fairly constant, 190 Mg to 240 jig/gm. The nickel content of the adjoining serpentine rock (1815 pg/gtul and its magnetic concentrate (2125 fig/gm) r however, were 10 and 11 times higher, respectively, than that of the cleaned fiber. The cleaned fiber showed a median chromium content of 19 Mg/gm com pared to 510 ptg/gm in the adjoining wall rock and 6525 Mg/gm in the wall rack mag netic concentrate. The latter data, however, are based on only two samples In one of which the chromium content was extremely high. The adjoining rock and its magnetic concentrate had two and four times as much cobalt as the cleaned fiber. Tlie manganese content of the wall rock was Ora times great er and its magnetic concentrate four times greater than that of the cleaned fiber. Addi tional information is being obtained on the variation in metal content of different types
of asbestos ore from separate geographical areas as well as on the metal content and relative solubility as the ore bodies change from surface to deeper sites. It is known that minerals frani outface ores often have different characteristics front those of ores at
deeper levels of the same ore body. Data in Tabic I show that mine-milled
chrysotile contains an appreciable amount of nickel, chromium, and manganese. The levels of cobalt \rere consistently low. Tables II. Ill, and IV indicate that considerable por tions of these metals are concentrated in the smaller size fraction of the- milled asbestos and that the trail rock and magnetic con centrate are a major source. It is not known, however, to wliat extent metals in the milled fiber may have also resulted from the abra sive action of the asbestos fiber on the metal alloys in the milling equipment or from dif ferent milling procedures. The extent to which the metals may be distributed between the respirable size grains or fibers is also un known.
Levels end Sources of Airborne Metal Exposures
In our study of the extent and source of metal exposures hi asbestos textile manufac turing, an asbestos textile manufacturing plant cooperated in setting up a special test run in which the Same batch of asbestos fiber of known metal content was followed through yticcersivc stages of asbestos textile menufact ui\. including fiVr preparation, .eaiuin?.
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SrptcmbcT'October, 1967
Table v Levels of Designated Metals to Bulk Chry*otile Fiber and in
Airborne Dual During Textile Manufacturing with Exhaust Ventilation Off
Opvrtt ton Fiber preparation
Pan rrmdinc Blvndini Blending and
icrtrtunt Fiboruin Combine
Cardiac
Spinning
Twisting
V.vtob
SlZJTpt*
Crude or* after open inf Blendint fiber Blended ond trreened fiber
KlbrrUtd btiloi Combed fiber Airborne dual from combi nod
fiber preparation operrfont Ratio of motal in Airborne dust
to metal In combed fiber Bulk fiber iniirmc carder Ruvin| leevinc carder Airborne dust it carder Ratio of metal in airborne dual
to*metal in rovuif Rev inf before tptnnin* Yam from tpirmer Airborne dual at ipmnrr Ratio of moral in airborne
duat to metal in yam Yam boforo twntinc Twitted yam Airborne duat at twitter Ratio of metal in airborne
duat to metal m twitted yam Filler yam Varp yam tertn aabeetat Airborne duat at loom Ratio of motel in airborne
dost to metal in woven aabottoa
% Ni
Metal in Sample1
% Ct
% Co
% Mn
0.02 0.16 0.16
0.10 0.07 0.16
2*3:1.0
0.07 0.08 0-2 2 2.7:1.0
0.01 0.04 0.13 1.6:1.0
0.08 0.09 0.12 U.1.0
0.14 0.14 0,14 0.16 1.1:1*0
<0.01 0.09 0.06
0.06 0.03 0.13
4J:1.0
o.os 0.04 0,17 4.2:1.0
0.04 0.04 0.11 2.7:1.0
0.04 0.04 0.07 1.7:1.0
0.06 0.06 0.06 0.07 1.2U.0
<0.0! 0.01
<0.01
<0.01 <0.01 <0.01
"
<0.01 <0.01
0.01 "
<0.01 <0.01
O.Ci
<0.01 <0.01
0.01 **
<0.01 <0,01 <o.oi <0.01
"
0.04 0.03 0.03
0.03 0.03 0.06
I.0:1.0
0.03 0.03 0.07 2.3:1.0
0.03 0.03 0.07 2.3;1.0
0.03 0.03 0.06 2.0.1.0
0.03 0.02 0.02 0.04 2.0:1.0
*A4Ju.t*4 to nrmii 0.017*; 0.017<v lOO^lg/g ^Filler *ad wp jwra dUI*rm batch than the special nn
spinning, and twisting. Ventilation was chromium 0.03 to 0.04 cobalt <0.01 r'r,
turned off during the tests, and operations and manganese 0.03 c/e.
were conducted to simulate procedures used
The airborne dust from the fiber combing
in the 1930's. Samples of bulk fibers were operations showed the following ratio in
collected as they entered and left each creases of metal contents over dial of the
process. At each process, airborne dust was combed and blended fiber: nickel 2.3; 1.0.
also collected on membrane filters by means chromium 4.3:1.0, cobalt, no difference, and
of high volume air samplers. These data are manganese 2.0:1,0. Data in Tables IT. III.
* shown jn Table V.
and IV indicate that a major source of the
The special test batch was made up of metals was the fines carried with the milled
approximately 60<e. of a commercially milled fiber. It is not known to what extent this
+ fiber of the type presently used in textile source may hare been supplemented by the
manufacture blended with 40<E pan ground abrasive action of the cltrysotile on the
No. 2 crude fiber added to simulate weaving processing equipment in fiber preparation.
4 grades of fiber of the mid-1930's.
As the chrysotile passed through the suc
Since a blend of two grades of asbestos cessive operations of carding, spinning, and
with different trace metal contents was used twisting, the ratios of metals in the airborne
in fiber preparation, it was impossible to re dust to the bulk fiber were: carding -- nickel
1 late specific trends in metal contents of the 2.7:1.0. chromium 4.2:1.0, cobalt, no differ test batch of asbestos previous to fiberizing ence, manganese 2.3:1.0: spinning -- nickel
and combing. The metal content of the bulk 1.6:1.0. chromium 2.7:1.0, cobalt, no differ
fiber remained fairly constant as it passed ence, manganese 2.3:1.0: twisting -- nickel
from blending, fiberizing. and combing 1.5:1.0, chromium 1.7:1.0. cobalt, no differ
through successive owraiions of ranting, ence, iiinncaneic 2.G:1.0.
twisting, anil spinning, nick*-l 0.07 to O.U9'i,
It was impossible tc follow processing of
.THIS DOCUMENT VMS NOT A RECORD OF t PPG INDUSTRIES, INC. DID NOT COME FROM
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IT'S FILES AND CANNOT EE AUTHENTICATED
BY PPG INDUSTRIES, INC. ; s.
[ 3245
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American Industrial Hygiene Association Journal
TABLE VI Designated Metala in Metal Alloy of Processing Equipment*
Processing Equipment
Fan Grtndtr Bottom of pan Roller
Carter Fimaher wire Flniohor it*dsr wire Breaker wire Breaker leader wire Leather apron
ttuia spinner Spinner exude wire
Rlnc spinner Spinner trees lar Spinner gxuda
Loon Drop wire beddlt
7# Ni
o.ot 0.03
0.01 0.01 0.02 0.02 0.0k
0.09
0.03 0.10
0.33
7- Cr
0.01 0.01
0.03 0,02 0.03 0.03 4 .60
0.03
0,04 2.37
17.00
7. Mn
0.40 1.04
0.6J 0J6 0.61 034 0.03
034
031 0.19
OJO
7. Co
0.01 0.03
0.01 0.01 0.01 0.01 <0.01
0.01
0.01 o.ox
0,0]
'Adjusted to nearest 0.017#; 0.017* w 100 jM't/I*
Table VU Airborne Levels of Designated Metals in Seven Asbestos
Textile Plants, 1961-65, by Operation
Operation
F lb*r pnHKUio Range Am UedLan Special run (vamllatlon off)
Ran.. Am|t U*UtD Sfwcial run (vantilatian att)
Ran*. Average Uadlan Soaclal ran Twtatin. JuBft Artfist Uadiaa Special rta* <eaotilatia etf) Veaeiu XK A.aiaq. IWdiao Spa, la1 m (eetniiation off}
Mleroerams of aiement per cubic meter of sir Ni Cr Co Mn
0J0.I.41
037 0.71 30.00
0.10-0.79 0.44-
0.39 20JO
0.01-0.3* 0.10 0.09 1.19
<0.01-0.70
0J3
oai toJ0
0S9,IJt
2.99 2.14 3S.00
0.44-1.*7 1.15 1.43
11.00
<0.01-0J 7 0,16
0.09 1.0*
<0.01.1 J*
0.91 0.69 (.94
1.15-7,17 3.31 2.64 IJS
1.02*39.0 a.i* 134 3.66
0.60*4.29 1.66 1.41 0.69
0*39-3.00 0.97 0.60 3.IS
0.07.1.10 0.26 0.13 0.07
0.02-oat 0.23 0.10 0.1*
<0.01.2.45 1.00 1.00 0J2
<0.01*2,47 1.0S 1.07 1J9
<0.01.4.36 0.73 0.01
1.74
0.03.1.7S 0J 0.13
UI
<0.01.0J7
0.06 0.03 0.0*
<0.01-3 J7 009 0.04 006
457
the same batch of asbestos through weaving because of the great amount of asbestos re quired for this operation. A separate test showed ratio increases of metal in the air borne dust over the woven asbestos of 1.1:1.0 for nickel, 1.2:1.0 for chromium, no change for cobalt and 2,0:1.0 for manganese. It was noted, however, that little dust was produced at tliis operation during the test period, and the operation may not have represented weaving during the mid-1930's.
It is likely there was continued release of the fines in the hulk chi votile being pro cessed beyond the blending and combing state
and that this constituted one source of the metals in the airborne dust. However, since tire percentage of metals in the bulk chrysotile at subsequent processing stages remained fairly constant and the ratio of metals in the airborne dust to bulk asbestos at carding was equal to that at fiber preparation, it is ap parent that a supplementary source con tributed metals to the air.
We studied the abrasive action of the as bestos on the processing equipment as a po tential source by testing for designated metals in representative metal parts of the proclaim: equipment having hur-li contact with the
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Scptcmbcr-October, 1967
Table Vm
Estimated Past Levels versos Current Levels of Designated Metals in
Airborne Dost in Asbestos Textile Plants by Operations
Tibor preparation pro 1930-35 I93S-45 currant (avocado)
Cording pro 1930-35 1935-45
currant (o*oraf)
Spinunc pro 1930*35 1933-43
TwUtLll* pro 1930*35 1935-45 currant Uvcrif)
frtvutt pro 1930-35 1935-43 ewnix (*v.r**)
Uieroframt of rlrrr.rnl per cubic mrtvr of air Hi Cr Co Mn
310.0 100.0
0.17
160.0
SO.O 0.44
9.0 4.5 0.1
0.0 40o.a0s
330.0 150.0
3J
250.0 130.0
1.1
15.0
7.0 0.16
120.0 10.0 0.91
10.0
10.0 3.3
7.0 1.0
4.0
7.0 1.0
4,0
1.7 0.26 1.0
29.0 7.0
1.1
17.0 4.0
0.97
1.0 0.22
1S.0 4.0
1.1
S2-0 17.0
0.72
36.0
12.0 038
2.0 1.0
0.06
20.0 7.0 0.39
Total Uctalc
460.0 230.0
1.7
720.0 310.0
SJ
22,0 22.0
6J
62.0 1S.0 10.4
110.0 37.0 ij
asbestos. These data arc shown in Table VI, The presence of these metals in the alloy of the processing equipment and the plant maintenance experience of frequent replace ment of equipment parts having immediate contact with asbestos indicate that the abras ive action of asbestos on the equipment is a supplementary source of airborne metal ex posure. This is further substantiated in that the fines from under the processing equip ment had an appreciably greater metal con tent than die bulk chrysotile being processed through the equipment.
PrvsanF and Past LavaIs of Airborne Matals
Airborne levels of designated metals in seven asbestos textile plants, 19G1-85, arc sliown by operations in Table VII. The low levels of metals in the air and the large air sample volumes required made it necessary to use stationary high volume sampling equip ment These samplers were placed near a number of operating units and in the im mediate vicinity of the workci so as to be representative of the worker's exposures. For com|jaratrvc information, the airborne metal concentrations of the special test run are also shown. Although die data presented in Table VII represent limited samples in that all types of processing, including different grades and blends of asbestos, arc not covered, it is believed that dies* represent realistic exjxisurc levels. Supplemental data on tilis will be reported later.
The average airborne levels for nickel in the seven textile planus combined ranged from 0.72 /tg/m5 at weaving to 8.14 /ig/nri at twisting. The maximum values, however, ranged from 1.41 jig/m3 at fiber preparation to 39.0 /ig/m3 at twisting. Average values for chromium ranged from 0.38 to 1.66 ag/m1 with maximums from 0.79 to 4.29 /tg/m3. Both average and maximum values for cobalt were under 1.1 *ig/rrr. Average values for manganese ranged from 0.33 to 1.05 ng/m* with maximums of 0.70 to 2.47 /ig/rn1. The increase in maximum over average values largely represented differences In the dust control programs, housekeeping, and maintenance between the different plants as well as operating practices and the nature of the product being manufactured at the time of the study. Additional sampling will be done to supplement these data and further define current exposures to metals in the manufacture of asbestos textile products.
It is important to note the sharp increase in metal content of the airborne dust when die ventilation was turned off. Table VIII shows estimated levels of metals in airborne dust of asbestos textile plants, by operations, during different periods of time.
Past exposures were estimated as follows: Total dust concentrations were determined at each operation of die special test run with d;c impinger-light ficM dust counting tech nique. Ratios of cast levels were estimated by contrasting concentrations a: digitated
L THIS DOCUMENT WAS NOT A RECORD OF AV
PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES. AND CANNOT. BE AUTHENTICATED BY PPG INDUSTRIES, INC.
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American Industrial Hygiene Association Journal
459
Table IX Lave!* of D**ient*d Metal* in Mine Milled Chrysotiie Before tad After Laboratory Grinding
Microfrftmft of maisi par cram of ehryioili*
Grtadinc quipm*rit
Mi Cr Co Un
Misar anil (eatnotuad tunefttan
c*rfrjct umii|
m$ * buidrr)
Grinding 10 sumn*
Soapla 1
()* Cb)' (e)*
365
360 --
197 193
--
37 73 2.0:1.0
279 2*0
Grindinf 10 minutas Grinding lOminuM*
&aa*pl* 2 Sinpit 3
(*) (b) (e)
<> (b)
<e>
630 at
--
1670 1500
--
170 165
--
1550 1500
--
47 315 4 *5:1.9
53 113 2.1:1.0
sto 430 0.3:1.0
423 405
--
Hftanar* mill (ehrorr* vital) Rocycla Ormdint (eotuwuour)
Sample 1
(-> (b) (e)
90 345 2.7:1.0
31 153 4.0:1.0
13 33 1.1:1.0
not dttarminad not datormmad
--
Orindine 10 hours
Sftnmia 3
(*) (bJ <e)
$30
660 --
170
59Q 13:1.0
47
3* 0.1:1,0
510 470
0.9:1.0
Bll mill (chroma stotl) Grinding i hours
SMpl* t
--______________________________________
C> (b) (e)
90 134 t J:J.O
31 114 3.0:1.0
13 t
0.1:1.0
not dttmlntd not datorminod
--
*() B*(on grinding; (b) After grinding; (c) Ratio* of mats! in ground to propound chrysotilo*
operations of the test run with concentra pg/m4 for chromium, and 120 gg/nri for
tions reported in past studies at the same operations. The metal concentrations found in the airborne dusts during the test runs were multiplied by these ratios to predict
manganese: fiber preparation: 210 jig/m* lor nickel, 160 ng/m3 lor chromium, and SO /ig/ms lor manganese. The values for cor responding metal exposures at wearing.
past exposures to metals. It is realized that Twisting, and spinning were considerably
this procedure for estimating past exposure lower. The massive dust during the earlier
_ _ has many limitations, since the relation of yean at fiber preparation and carding are
dust counts to mass values is quite variable known to have contaminated the ambient
and the information on respirable mass of air at subsequent operations so that the
past airborne dust at the operations studied predicted values at spinning, twisting, and
is unavailable. However, with the finding weaving arc somewhat low.
-- that the metals of the airborne dust around
The values for metals in airborne dust for
processing equipment rose sharply when the the period 1935-45, during which dust con
ventilation was turned oil, it is important trol programs were generally initiated, weic
that estimation be made of past levels of estimated at around 50# of those during
exposures to metal during the periods when the previous period. After World War II.
dust control was lacking or less effective.
there was greater emphasis on dust controls
Data in Table VIII show that a rather and levels gradually were reduced to the
uniform ratio existed between the airborne values found during 1961-65.
levels of nickel, chromium, and manganese
at different operations with chromium rejs-
In contrasting exposures of the pre-1930-
resenting 70 to 80# and manganese 40 to 35 period with those of today, the exposures
l 50# of the nickel values: exposure to cobalt to the total metals reported wrre greater by
was minimal.
a conservative factor of 270 at fiber prepara
In the past, the greatest levels of airborne tion. and 140 at carding. Although the data
dust occurred at carding and fiber prepara show factors of 70 at wcaving, 7 at spin
tion, followed by weaving, twisting, and spin ning. and 6 at twisting, these are undoubt
ning. In die pre-1930-35 period, level* of edly nure low due to the gross cc.mamir.n-
exposure were conservatively estimated, at tiou of the general ambient air which, in
carding, to be: 330 /ig/nd lor nickel. 250 the past, existed throughout all op. ations.
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0/C<iC3
460
Grinding of Asbestos for Laboratory Research
metals in processing other types of asbestos? What is die distribution of there metals in
the respirable grains and fibers? It is plaus
In preparing asbestos for animal dosing ible diat die phenomenon observed in as
studies, it is often the practice to grind the larger size fibers to the lower micron range using equipment such as the hammer mill and the mixer mill. To test the extent to
bestos textile manufacturing will also occur in odicr processing of different types of as bestos. litis being true, the metals associated with the asbestos may have a different quali
which metal contamination may occur dur ing the breaking down of the asbestos fibers
tative and quantitative pattern depending on the type, grade, and source of the asbestos,
through laboratory milling, chrysorile with a known percentage of designated metals was reduced in a hammer mill and a ball mill, made of a chrome steel alloy, and in a mixer mili made of cemented tungsten carbide with cobalt as a binder. It was found that chry-
the equipment in which it is milled and processed, and the subsequent treatment of the milled fiber.
Also, the qualitative and quantitative pat tern of the metals in die airborne dust at asbestos processing operations may vary sig-
sofile, after being ground for ten minutes in a cemented tungsten carbide mixer mill, picked up increased cobalt in ratios ranging from 2 to 4.5 over that in the preground
nificandy from die metal content of the asbestos crude and milled fiber since the metals appear closely associated with low micron size fraction of the particulates and
asbestos. In the hammer mill, the increase fibers.
of chromium ranged from 3.5 to 4.0 over
the amount present in the preground asbes
In simulating past procedures of grinding
tos. The ball mill showed about the same asbestos for animal studies, it has been shown
relationship with increases of 1.5 for nickel that chrysotile abrades and incorporates por
and 3.0 for chromium over the preground tions of the metal alloy in which it was
chrysotile. It is apparent that the asbestos ground. These factors of extraneous metal
abraded the metal in which it was ground. exposures should be reassessed in terms of
This supports the premise that the abrasive past animal research, especially since much
action of asbestos on processing equipment of the evidence of die carcinogenicity of
metal may be an unsuspected source of air asbestos is based on animal research data.
borne metal exposure.
We need much more information on the
levels of metals in tissues from deceased
Discussion
workers known to have had asbestosis, and also from King cancer and mesothelioma
The data presented show that workers in the asbestos textile manufacturing industry, in the past, were exposed to airborne dust containing significant levels of nickel, chrom ium and manganese. Limited studies indi
cases with and without known exposure to asbestos. Information is uL*o needed on die levels of metals in the blood and urine of workers with prolonged heavy and light ex posures to asbestos.
cate that other metals are also involved.
The significance of die presence of these
, These metals come from minerals and native metals in past exposures is not clear. It is
T alloys associated with the asbestos mineral reasonable to consider their relationship with
body and from the abrasive action of the the increased pulmonary and odicr cancers
| asbestos fiber on metal components of the observed in asbestos workers.14"15
i
processing equipment and raise a number
In addition to the fact that die nature
! of important questions involving areas in and source of the metals associated with air
! which additional research is needed. What borne dust ex]iosures in die processing of
| odicr metals are associated with the mining, asbestos are important with respect to ex
' milling, and processing of asbestos? In what posure evaluation and contamination con
precise chemical forms are these metals pre trol. Haring!on13 showed that serum elutes
sent and what is the pattern of exposure to significant quantities of metals from difTcr-
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IT'S INC` DiD NOf C0ME Fl IT b FILES AN[>. CANNOT PE AUTHENTIC '
BY PPG INDUSTRIES, INC.
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NOTE: THIS NOT COME FROM PPG rri1'i1'.LOrs
American Industrial Hygiene Association Journal
461
ent types of asbestos. The presence of these metals and other associated materials should be studied in relation to variations of chest rocmgenographic and the health patterns of workers as observed from one group of as bestos workers to another.
The specific role of the asbestos fiber, per sc, in relation to disease observed in asbestos workers needs redefining. Although asbestos fiber was considered in die past to be the primary etiologic agent, it may have been only an arbitrary index concealing a spec trum of undefined agents and relationships. Its role must be reassessed as a co-factor acting with other agents.
Summary
Asbestos textile workers processing chrysotile were exposed, in the past, to signifi cant airborne levels of nickel, chromium, and manganese. Limited studies indicate thaf other metals were also involved. It is Hkrly that the phenomenon shown in as bestos textile manufacturing is also true in other asbestos mining, milling and process ing operations. The qualitative and quanti tative pattern of these airborne metal expos ures may vary significantly from the metal " content of the crude asbestos ore and milled fiber.
The relationship should be investigated between these metal exposures and the in creased pulmonary and other cancer ob served in asbestos workers. Other varying patterns of pathology including altered chest roentgenograms, pulmonary function tests and worker health patterns should be con sidered in relation to these exposures.
Sufficient evidence is presented in this studs* to indicate that the role of metals in the etiology of disease associated with asbes tos inhalation should not be ignored. It is no longer tenable to look only for asbestos fibers or bodies in biological tjssue and hy their presence assume a cause and effect re lationship with the disease.
Acknowledgments
The authors acknowledge, with apprccia-
4" 4 .
THIS -DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC.
tion, the technical assistance Richard . Kinser, Theodore D. Martin, and Patricia A. Mauor, who set up the atomic absorp tion spectrophotometric procedures and per formed the analyses for nickel, chromium, cobalt, and manganese, and to George H. Edwards and Doughs L. Johnson, who as sisted in collecting and preparing the en vironmental samples.
References
1. Maaouxb. F.: Ubrr EimnunJiffc* Pfrmmikri'uQ*
in Dtn Lupftn. F#rh. &utk. Pttk. Get. 10: 223 I1W),
2. FktiA. T.. and E, Fmocl: DfUMOiimwi! Prrpamtn
ttnd Xnkroyhotnqrainni* vnn timm Fai> von rm-tionn eoniom, Mnnek. Med. ll(?/.* 8^5 {1V5-I *
1 Coosa. IV. X: 57a (1929).
inr AehcstoMa. fail* Med. J. 2:
4. PflXl., R.: Mortality (ran Lon? Cuftt in Ashnm
Wwtfa fait. J* Indus*. Med. 12: 8i M?53j. 5. Mtxcrao. T, F.. and F.. J. Coct-Tn: Mrthc-dwhwr
in Industrial Health Studies. Aetk. n*Vro. Ileetih 6: m (U43).
6. Stuxorr, I. J., J, Ocm, and E. C Uamxoxi*: A*,
bofoa Lipoiart and
Presented at a Joint
Mmifty of tho Scetiooi on Rtdiihoy* and D**<",*> of
the CHru of the .\jprriran Medical AtMiroiNm and
tfec AfDfTKii Cellftv of Clou pbvJeon on Jure 17,
19C3, at Atlantic City. X, J.
7. J. C,. C. A. Xtiwi, and ?. Mascjia^o; Dif
fuse PletaaJ Mesothelioma and Afbenna Lipcmirt in
dm North
Cap* Proeinc*. fait. J, Indus.
Med. IT: 2fi0 ilttO),
E xnaLm, P, L; Mortality Among A^xn Pmd* Otth Workers is tho Umttd States- AnuM* .V. )\
` Ae*d. Sei. 132: 156 -I3u3j.
9. Lyuot, K. M.. and W, A, 5Mmt; CaniiiutiiJ of Umf in Aibciiooitiimia. dm. J. Ceuete 24:56 (PJJ.V,.
10* Glotxs. S, R,: Vtiamoua Carcinoma of I_mn Orin Aihwmlir Tm CTatn, TnhertU 17: 5 t)933i.
11* EoMJtT, 0. S-, and A. J. Grtcas:
Ad*-s-
tom and Circiptuno Amrr. Her. of Tmkere 34: 143
(1936).
12* Dajc*. E. L: A Tewdxmk nf Minin lop. Job* W3cr A S--. loe^ New York U90&).
13. Btma, H.: Adirnoe Fundamental*: Onein. Pi openie*. Mining. lYuerwiiit. Uiilixataoit. TramUmi fmn rbt
Ccrtno by Ralph . Oerter. Gbcmwal Publithurx O* . 2n&* 212 Filth Av*,, New York il96il.
14. Nicra*. L II.; T7m Onwrwr of Xitkt NWhe!* Iron in the Srrpcmiae Rock of liar Eatrrn To**-n*).to
of Qorhrc Plainer, The Cmrnfdimm Miuvniutnt 6: 30T 0959).
13. Haoixotox. J. S.. and F. ]. C* Roc; Smdin *f
OfnltMta of AOmo* Fihn and Tbrir Naiuml Oik. Annul* X. V. Acud. S*i. 132: 429
16. MAntoWATnto. E.: twmal Hraith
A Review M Jti OrfuM/. Oeenp, Med. 9; 12T OW7
17. Dot 11 R-: OccnpoHonai Luite Ganrrr: A RiWw. fait. J. Imdrnt. Med. /<: 181
18. Roc. F J. C- and M. C. L\,hcastui; NatunJ, MrtaJHc and QHrr SiiUuvO. a* Cairmomn. Mrrhaniwa nf Cardnonmkct; ChrwJrti. Pkyvcai and \*umL fait. Med. Hull. 20: Jt (JIM).
19. St'.yaany^. F. \Y.,, jr-; lnhibitioti, nf !ndurti**n of
Bmwfnrw HydroUm br Nirhrl Carbon*!. Center Rftemrfk (To bv in pm is May 1967 inw,
2D. Sr^ncnxAX. F. w,, Jr,; Niekrl Gubowr! Inhibition of Cortt*onv IndurinHi of Kepotk Trsptupkan PvrrnUar. Caarrr Reteutek I in pti n>.
21* R. L.. and F. W.
Ja.: Arm*
hrtmlwic Rrartion to Varenirrai Adsumatratton of
Nirlal CmLanni. A*<k. L+cirmm. Heuitk I u* prr>)
22.
j. *:
'Y. f!., and *V. W. F*v*rt,: ^pmttteonl in Mei^J C*rctmwesk. An*. Hunt***. U.mtn
Rifiitnl Jaat 1 7.67
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