Document D0ew2NN7rVgd0wveYGBxQ2qB
Memorandum to: From: Subject:
The Hearing Clerk Food and Drug Administration Room 6 - 8 6 5600 Fishers Lane ROCKVILLE, Md. 20852, U.S.A.
Hedman Mines Limited P.0. Box 590 TIMMINS, Ontario, Canada
Proposed Rules, Asbestos Particles in Food and Drugs 21 CFR, Parts 133 and 121.2006, Section C2.
In Part 133 it is stated that "Chrysotile, a tubular serpentine mineral, accounts for 95 percent of the world's production. The others, all amphiboles (crystals with 3 groups of metal ions) are amosite, crocidolite, anthophyllite, tremolite and actinolite."
Section C2 of part 121.2006 proposes that "a count of not more than 1000 amphibole types of asbestos fibres and not more than 100 chrysotile asbestos fibres per milligram-slide constitutes the maximum for these asbestos fibres in talc".
The following, and the supporting evidence, will show that amphiboles gene rally, and crocidolite and amosite in particular, have shown, in medical statistics, including research by those listed as reference in F D A 's Notice of Proposed Rulemaking to be far more dangerous to health and more likely to be cancer-inducing than chrysotile.
a) Amosite (Amphibole Asbestos) Dr. Irving J. Selikoff et al, New York, show in their study "Carcinogenicity of Amosite Asbestos" that amosite asbestos factory workers had a mortality rate more than twice that of the one expected and a mortality rate from cancer of the stomach, colon and rectum 3 times higher than expected. (Exhibit "A")
This compares with an extensive study by Dr. J. Corbett McDonald at McGill University, Montreal, which shows that from a sample group of 10,421 chrysotile asbestos workers, only the 5 percent that were exposed to high concentrations of chrysotile had a mortality rate 209 higher than the general population, and among the 95% of the chrysotile asbestos workers there was little or no excess mortality. (Exhibit "B")
b) Crocidolite (Amphibole Asbestos)
1. ) British Government, Department of Employment, in the brochure "Asbestos: Health Precautions in Industry", state: "Crocidolite may be more dangerous in this respect (mesothelioma) than are the other forms of asbestos", (Exhibit "C") and: "Sometimes the less harmful chrysotile has been used to replace crocidolite", (Exhibit "D") and ".... old asbestos lagging will have to be stripped - sometimes in its most dangerous form, crocidolite - and precautions have to be scrupulously observed." (Exhibit "E")
2. ) UK Department of Employment, HM Factory Inspectorate, Memorandum of the Senior Medical Inspector's Advisory Panel, Section 41: "... we feel it is with our competence to recommend that, unless special considerations operate, crocidolite should wherever possible be replaced by another variety of asbestos, and whatever measures may be adapted to control asbestos dust, these must be even more rigidly applied to crocidolite. (Exhibit "F"J
- 2-
b) Crocidolite (Amphibole Asbestos) - continued 3. ) UK Asbestos Regulations 1969 (in force currently) specify the maximum number of fibres per cm3 as 0,2, while they allow 2.0 chrysotile fibres per cm3. They also specify a maximum of 0.01 mg per m3 for crocidolite, but allow 0.1 mg/m3 for chrysotile. (Exhibit "G"5
4. ) German Asbestos Regulations 1973* recognizing the more dangerous aspect of the amphiboles, do not allow any emission of crocidolite fibres into the air. while they allow a chrysotile air-borne fibre emission of 0.13 mg/m3 max. (Exhibit "H" )
i c) Anthoohyllite. Tremolite and Actinolite The limited medical or scientific studies do not appear to suggest that they are safer than other forms of amphibole asbestos. Their limited use and therefore lack of statistics does not imply that their fibres are less dangerous to health than the chrysotile fibres.
d) Summary 1. ) Amphiboles, especially crocidolite, are internationally considered to be more hazardous than chrysotile.
2. ) Government Asbestos Regulations in several countries recognize this by much stricter standards for amphiboles than for chrysotile, which is recommended as a substitute. In no country, including the U.S.A., are current asbestos regulations stricter for chrysotile than for amphiboles.
3. ) British Asbestos Regulations restrict the emission of the crocidolite amphibole fibres to only one tenth of that permissable for chrysotile.
4. ) In the light of the evidence presented herewith, and in the interest of public health, it is herewith petitioned that Section C2 of Part 121.2006 of the Proposed Rules, dealing with the maximum count of asbestos fibres allowed for amphiboles and chrysotile in talc be roversed to read as follows: "A count of not more than 100 amphibole types of asbestos fibres and not more than 1000 chrysotile fibres per milligram-slide constitutes the maximum for these asbestos fibres in talc. These limits assure a purity of talc at 99*99 percent free of amphibole types of asbestos fibres and at least 99.9 percent free of chrysotile asbestos fibres."
December 12, 1973
Memorandum to:
From: Subject:
The Hearing Clerk Food and Drug Administration Room 6 - 8 6 5600 Fishers Lane ROCKVILLE, Md. 20852, U.S.A.
Hedman Mines Limited P.. Box 590 TIMMINS, Ontario, Canada
Proposed Rules, Asbestos Particles in Food and Drugs 21 CFR, Parts 133 and 121.2006, Section C2.
In Part 133 it is stated that "Chrysotile, a tubular serpentine mineral, accounts for 95 percent of the world's production. The others, all amphiboles (crystals with 3 groups of metal ions) are amosite, crocidolite, anthophyllite, tremolite and actinolite."
Section C2 of part 121.2006 proposes that "a count of not more than 1000 amphibole types of asbestos fibres and not more than 100 chrysotile asbestos fibres per milligram-slide constitutes the maximum for these asbestos fibres in talc" .
The following, and the supporting evidence, will show that amphiboles gene rally, and crocidolite and amosite in particular, have shown, in medical statistics, including research by those listed as reference in FDA's Notice of Proposed Rulemaking to be far more dangerous to health and more likely to be cancer-inducing than chrysotile.
a) Amosite (Amphibole Asbestos) Dr. Irving J. Selikoff et al, New York, show in their study "Carcinogenicity of Amosite Asbestos" that amosite asbestos factory workers had a mortality rate more than twice that of the one expected and a mortality rate from cancer of the stomach, colon and rectum 3 times higher than expected. (Exhibit "A")
This compares with an extensive study by Dr. J. Corbett McDonald at McGill University, Montreal, which shows that from a sample group of 10,421 chrysotile asbestos workers, only the 5 percent that were exposed to high concentrations of chrysotile had a mortality rate 20$ higher than the general population, and among the 95$ of the chrysotile asbestos workers there was little or no excess mortality. (Exhibit "B")
b) Crocidolite (Amphibole Asbestos)
1. ) British Government, Department of Employment, in the brochure "Asbestos: Health Precautions in Industry", state: "Crocidolite may be more dangerous in this respect (mesothelioma) than are the other forms of asbestos", (Exhibit "C") and: "Sometimes the less harmful chrysotile has been used to replace crocidolite", (Exhibit "D") and ".... old asbestos lagging will have to be stripped - sometimes in its most dangerous form, crocidolite - and precautions have to be scrupulously observed." (Exhibit "E")
2. ) UK Department of Employment, HM Factory Inspectorate, Memorandum of the Senior Medical Inspector's Advisory Panel, Section 4lJ "... we feel it is with our competence to recommend that, unless special considerations operate, crocidolite should wherever possible be replaced by another variety of asbestos, and whatever measures may be adapted to control asbestos dust, these must be even more rigidly applied to crocidolite. (Exhibit "F"l
- 2-
b) Crocidolite (Amphibole Asbestos) - continued 3. ) UK Asbestos Regulations 1969 (in force currently) specify the maximum number of fibres per cm? as 0.2, while they allow 2.0 chrysotile fibres per cm3. They also specify a maximum of 0.01 mg per m3 for crocidolite, but allow 0.1 mg/m3 for chrysotile. (Exhibit "G")
4. ) German Asbestos Regulations 1973, recognizing the more dangerous aspect of the amphiboles, do not allow any emission of crocidolite fibres into the air. while they allow a chrysotile air-borne fibre emission of 0.15 mg/m3 max. (Exhibit "H")
c) Anthophyllite. Tremolite and Actinolite The limited medical or scientific studies do not appear to suggest that they are safer than other forms of amphibole asbestos. Their limited use and therefore lack of statistics does not imply that their fibres are less dangerous to health than the chrysotile fibres.
d) Summary 1. ) Amphiboles, especially crocidolite, are internationally considered to be more hazardous than chrysotile.
2. ) Government Asbestos Regulations in several countries recognize this by much stricter standards for amphiboles than for chrysotile, which is recommended as a substitute. In no country, including the U.S.A., are current asbestos regulations stricter for chrysotile them for amphiboles.
3. ) British Asbestos Regulations restrict the emission of the crocidolite amphibole fibres to only one tenth of that permissable for chrysotile.
4. ) In the light of the evidence presented herewith, and in the interest of public health, it is herewith petitioned that Section C2 of Part 121.2006 of the Proposed Rules, dealing with the maximum count of asbestos fibres allowed for amphiboles and chrysotile in talc be reversed to read as follows: "A count of not more than 100 amphibole types of asbestos fibres and not more than 1000 chrysotile fibres per milligram-slide constitutes the maximum for these asbestos fibres in talc. These limits assure a purity of talc at 99.99 percent free of amphibole types of asbestos fibres and at least 99.9 percent free of chrysotile asbestos fibres."
December 12, 1973
> - fe
*
*
r i
I
j
r 4
<*
5-r*>
- 1 ( >> ' f i s . : ' s - 1 ,
, s l W . Vn>-T E T A L
,
I V m i n e d . me a n a l . ' i. f \ '
! V. *.
u a ) , i f f .
5 i m- } f x t "T ( O.l r i ;i-m l ii'os s f: n i
lu n p s or im d v i d u a l , r. Vis c o l i o r W 1 11
iii d. T .a rg n u m b e s OL h o a r s w ? e 1
K !. c t r o n d it f r a c t i o n : i n d e l e c t r o n I ' d '!' 1
,i rl a l y s i s ? h o w e d t h e 71 to b e a m o s i e 11 :c t [i
t i r t h e o c e a s i o n a l c )i y sc -file f i b r i l i xpei e I-
hi > p r e s e n t in t h e h ir g5 o f u r b a n five- -t i;
th is u re a .'--
Results
The mortality experience of th s group o workmen, 1960 through 1971, d e r o n ;i.vu that a serious health hazard was esse :i with this industrial use of amosi:e. T ib < records expected a id observed deaahr>
Total deaths were more than twi::e b number anticipate!: 46.4 were espscte tl : n 105 occurred. This excess death ra e tv limited to two categories: cancer; of vac n sites and asbestosis.
Fourteen deaths were due to asbesfosi when virtually none was expected Th; amosite can result in asbestosis has bet previously recognized.1234567* In physiologic studies of a select group of wort men at l:b particular factory from 1954, serious pi monary insufficiency had been demo strated.13
Both lung cancer and mesothelioma we also found in considerable excess, 'll: w.
iv uai.*: i ~afc 2.1 (b aths from iung carte? !
i ,< evmnitde; 25 occurred. The calcu ? !
. ' sc per.od rale1' disregarded smokin
ht si ice Ihe smoking habits of indivira .
: n it tj.imined by us are not accurate] *-
la )v a. In onispective studies from ta p
i rit on, racking habits will be taken in'j
. . oi nt.I{
.
vlcsotlialioma caused five deaths: tv
s mal and three peritoneal. Each has her j
tk to logically verified in material obtain ]
i uring cperations in two instances and. rff ,,
onto icsies in three. In one case, there h tf I
irem prior cfirysotile exposure; in four, cry;
si nosite asbsstos exposure had occurai "
I ' irf nthetically, additional instances of m i '2
i ssli oms have occurred among men woria i l
i s this plant, other than in the cohort .'a- h
jisited tore
2i
It maj- be of interest that more deab_ \
fn m cancer of the stomach, colon, and n s- ?
lurn 'liavi! occurred than expected. The as k
Is'ease^s' oiily threefold, however. As vuii |
.nilar previous experiences, further obi a- ;
nations are required before this associatior |
,:nn be regarded as clearly established.10 T. S
T his investigation has been supported. in par by ? i
risearch jrar t E S 00358 of the N ational Insiirufc?
cl Environmental Health Sciences, U S Departriffil-
<:f Health, Education, and Welfare.
5-
Field investigations were carried out by Dciritir ~
Pen on, Shirley Levine, Rayla Margolies, and Chaife^
0. Nolan. '
*>_
u TP!cea
1. W hipple HE (ed ): Biological effects of asb >
tos. Ann N Y A cad Sci 132:706-721, 195. 2. W agner JC, Berry G: M esotheliom as in r;f
following inoculation with asbestos. Brit J Canr
23:567-581, 1969.
3. Sm ith WE, M iller L, Churg J: An experinv i
tal model for study of co-carcinogenesis in, 1 respiratory tract. Oak Ridge, Tenn, A tom ic Erie'a Commission symposium series 21, 1970, pp V9-3
4. M cDonald JC, M cDonald AD, Gibbs GW, al: M ortality in the chrysotile asbestos m ines 11 m ills of Quebec. Arch Environ Health 22:677-111
1971
.
5. Wagner JC, Sleggs CA, Marchand P: Diflu
pleural mesothelioma and asbestos exposure in ti
N orth W estern Cape Province. Brit -7 Induft<- ill-
17:260-271, 1960.
6. K iviluoto R, M uerman L: R esults of nsbeC
exposure in Finland, in Shapiro HA (ed): Promt a
ings of International Conference on Pneiimocanuhv
Johannesburg 1969. Capetown, South Africa, Oxlc,
University Press, Inc, 1970, pp 190-191.
7. Sluis-Ciemer OK: Asbestosis in South Af if
Certain geographical and environmental ecu s id e
tions. Ann N Y Acad Sci 132:215-234, 1965.
8. Sluis-Cremer CK: A sbestosis in South Af ir|5?
asbestos miners. Environ Res 3'310-319, 1970. 7. d
9. W agner JC: Asbestos cancers, editorial. J
Career Inst 46'v-ix, 1971.
10. Selikoff IJ, BadeRr A, Bader M E, et- a!J
Asbestosis and neoplasia, editorial. Amer J m T|.
42:487-496, 1967.
r-
II. Lunger AM , Rubin I, Selikoff IJ: E led rci j:
microprobe analysis of asbestos bodies, in Shapiri j ,
HA (ed): Proceedings of International Conference,?
on Pneumoconiosis, Johannesburg 1969. Capetowitf*
South Africa, Oxford U niversity Press, Inc, 1970,
57-69.
' :J
12. Langer AM, Selikoff TJ, Sastre A: Chrvsotis
asbestos in the lungs of persons in N ew York CityS^.
Arch Environ Health 22.348-361, 1971.
13. Bader M E, Bader RA, Selikoff IJ: Pulmonary-.-.-
function in asbestosis of the lung: An alveolarcapJ-^ |
lary block syndrome Amer J M e d 30.235-2-12, 196L- -.
14. Selikoff IJ, Hammond EC. Churg J: Asbestos
exposure, smoking, and neoplasia. J A M 1 2 ()4 'i0by 1
112,1908.
.
15. Selikoif IJ, Churg -1, Hammond EC: A-hestar
exposure and neoplasia. J A M A 188 22-26, 1964. . i
,
A rc h Environ t h `I,-- Vul 2b, S " p ' 19/ 2
- L J J 'J L iiu j) jlF
O c to b e r ' /9"7/
c : a o a A. j { /] / h ' l f l i / I Q daorn&{ O -T o b id 9 7 /
Report claims mortality rite lower among asbestos workers
and present male employees had been subject to h m h e x p o s ijre s arid that
in this groupm<^rnc)T,iTiFy was roughly
EJA sa m p le g r o u p o f 10421 3:=st and
200 higher than that to be expected
p re s e n t a s b e s to s p r o d u c t io n v /o ik e r s in in an u n nxposeri p opu ation of
Q uebec, in c lu d in g a t o t a l o f ',981
corresponding ages
men, was found to have a mortality's
Tim report notes this "excess m or
rate from ail causes lo w e r then the 1 ta lity '' was accounted for fry a rise in
level expected in the general Quebec J the number of deaths due to
population. This is one of the findings respiratory and cardiac disease and
of a scientific paper published in
an increase in d eath s from cancer
th e J u n e 1971 issue of th e " A r c h i v e s
of the lung.
of Environmental Health".
j Among the 95% of asbestos
\
Dr. J. C o rb e tt fd|cDonald, head o f I p ro duction w o rk o rs w h o did not have |
McG ill's D epartm ent of Epidemiology | high dust exposures, there was little or
anc hVa'th, Dr. A li s o n D. M c D o n a ld ' no e x c ess m o r t a lit y fro m th e se c a u s es. ,
and three other research workers,
fill! report oeais out the conclusion
Graham G m b s M .S c , Jack S e m ia ty c k i reached by Dr. J C M c D o n a ld in an
and Charles Ressiber M A,
earlier epidemiological survey of the
co-authored the report. It covers a
incidence of mesothelioma in Canada,
three-year stu d y com pleted in 1970 of J namely that primary malignant meso- \
the health of 11,788 employees of
{ thelial tumors were rarely associated J
Quebec's asbestos minmg industry
' wuh_j^M^soi]p asbestos production. /
born b e tw e e n 1891 and 1920.
Involved in the study w ere over a
C h ry s o tiie is the only variety of the mineral tibre to be mined in Canada.
dozen medical and statistical re
" I t is clear that the Quebec c h ryso tile l
searches, aided by the Quebec
w orkers have had nothing like the
asbestos naming industry's tw o
experiences of the American insulation
employee health clinics, the Quebec
workeis or the London factory
Department of Demography, the federal workers w ith respect to malignant
Department ot Health and Welfare
mesothelioma, and it seems unlikely
anc the U ne m p lo ym e n t Insurance
that they arc compatible with respect
Commission Their combined efforts
to lung cancer," Dr McDonald
r e s u lt e d in 'T r a c k in g d o w n 88.4CT of the c o n c lu d e d in his 1971 report.
11,'AT past and present asbestos
"These findings strongly suggest
industry employees. Of these 2,457
either that
(23 6'/r) had died.
cause malignant disoaso of the lung
When the lengths of time of the
and pleura than other forms of asbestos.
m e n 's e x p o s u r o t o a s b e s to s d u s t and suen as c r o c i d o h t e, or th a t w o r k e r s ^
the concentrations of the dust during
engaged in insulation and processing
this time wore calculated, it was
pro exposed to additional factors which
found that about 57- of the 9,981 past ^explain the difference "
At c meeting of asbestos production
mnnugament and labor representatives
m Idietford Minos, Oue., in February
1970, , k i o i to p u b lic a tio n o f his 1971
paper h McDonald r tated, "in view of^ these 1m dm g s in a sb e s to s p r o d u c t i o n J
w eaker;, it is d ifficu lt to believe that (
the very much lowet levels of chry-
y
sotile asbestos to which the general
public s exposed under normal
circumt fences could constitute any
appreciable health hazard."
--^
Dr McDonald and his research group
at McGill University proposed the
epidemiological survey of Quebec's
asbestos production w o rk e rs in 1965. The s tu d y w a s la u n c h e d in 1966
w itii support from the Institute of
Occupy mnal and Environmental Health.
Tim mechanism for such a study was
set up w ith the cooperation of Quebec's
seven .asbestos-producing companies,
labor unions and thousands of industry
employees who volunteered to take
the necessary tests.
McGill University's epidemiological
research program into the relationship
between asbestos and health is being
continued at least until 1975.
0
E th ibit "B*
MAK-Werte 1973
Maximale Arbeitsplatzkonzentrationen 1973 der Kommission zur Prfung gesundheitsschdlicher Arbeitsstoffc der Deutschen Forschungs
gemeinschaft
Bek. des BMA vom 15. August 1973 - III b 4 - 3745.81 - 2573 73
Die sorbezeichnete Kommission (Anschrift: 53 Bonn-Bad Godesberg 1, Kenncdyallce 40) hat in ihrer Mitteilung IX die nachstehende Liste maxi maler Arbeitsplatzkonzentrationen (MAK-Werte 1973) beschlossen, die hiermit bekanntgegeben wird.
Diese Liste tritt an die Stelle der im Bundesarbeitsblatt - Fachteil Arbeitsschutz - Heft Nr. 10/11/1972, S. 382 ff., verffentlichten MAKWerte-Liste 1972.
M axim ale A rbeitsplatzkon2entrationen gesundheitsschdlicher Arbeitsstoffe (M AK-W erte) 1973
I. B ed eu tu ng und B enutzung von M AK-W erten
Definition
Der MAK-Wert (maximale Arbeitsplatz-Konzentration) ist diejenige Konzentration eines Arbeitsstoffes als Gas, Dampf oder Schwebstoff in der Luft am Arbeitsplatz, die nach dem gegenwrtigen Stand der Kenntnis auch bei wiederholter und langfristiger, in der Regel tglich Sstndiger Ein wirkung, jedoch bei Einhaltung einer durchschnittlichen Wochenarbeitszeit bis zu 45 Std. im allgemeinen die Gesundheit der Beschftigten nicht beein trchtigt. Bei der Aufstellung von MAK-Werten sind in erster Linie die Wirkungscharakteristika der Stoffe bercksichtigt, daneben aber auch - so weit mglich - praktische Gegebenheiten der Arbeitsprozesse bzw. der durch diese bestimmten Einwirkungsmuster. Magebend sind dabei v, lssenschaftlich fundierte Kriterien des Gesundheitsschutzes, nicht die tech nischen und wirtschaftlichen Mglichkeiten der Realisation in der Praxis.
Voraussetzungen
Voraussetzungen fr die Aufstellung eines MAK-Weries sind ausrei chende toxikologische und;oder arbeitsmedizinische bzw. industriehygieni sche Erfahrungen beim Umgang mit dem Stoff. Erfahrungen am Menschen
Bestcll-N r. Z H 1,401 ' Carl 11c.: '..u.us Ye-i.ig K G, 5 K o la 1, C-LLonstra.W 18-32
B) Fibrogne Stube
Als fibrogene Stube werden in dieser Liste Stube bezeichnet, die mit Bindegewebsbildung einhergehende Staublungcnerkrankungcn (z.B. Silikose und Asbestose) verursachen knnen. Voraussetzung fr die Entstehung dieser Erkrankungen ist die Dposition des Staubes im Ah eolarbereieh und seine spezifische Schdlichkeit. Zur Beurteilung fibrogener Stube ist des halb die Feinstaubkon/entration heranzuziehen.
Quarz (einschlielich Cristohalit und Tridymit)
Quarz, Cristobalit und Tridymit sind beim Menschen als silikoseerzeu gende Stoffe bekannt. Ein Feinstaub gilt dann als quarzhaltig, wenn er mehr als 1 Gew.-/o Quarz enthlt. Im Steinkohlenbergbau gilt der Wert 4,0 mgn3, wenn der Quarzgehalt im Fcinstaub weniger als 5 Gcw.-n/o betrgt.
Aj,P't ^ (See T r a n s la tio n frora German, below)
Die verschiedenen Asbestarten knnen beim Menschen bsartige Tumoren | (Karzinome und Mesotheliome) erzeugen. Dies scheint beim Lumlwzdolidt ; am strksten ausgeprgt zu sein. Ein MAK-Wert kann d ah e ^v g l^T T ! ^cmH^O n,cht genannt werden. Um dem Arbeitsschutz fr die zu trefI fenden technischen Manahmen und die berwachung am Arbeitsplatz j einen Anhalt zu geben, werden fr den gewerblich berwiegend verwendej ten Chrysotil-Asbest vorlufig folgende technische Richtwerte genannt:
j Chrysotil-Feinstaub
| Chrysotilhaltiger Fcinstaub
0,15 mg/m3 4,0 mg/m'1
' Diese technischen Richtwerte stellen auf die fibrogene Wirkung (Asbe stose) von Chrysotil-Asbest ab. Die Einhaltung dieser Richtwerte schliet das Krebsrisiko nicht aus.
25
0*
A sbestos The v a rio u s a s b e s to s ty p e s can im part to humans m alig tumors (cancers and m esotheliom a). C ro cid o lite appears to give th e stro n gest, evidence_tp__that e f f e c t. Vhererore a
maximum c o n c e n tra tio n v a lu e (TVL) cannot be g iv e n . The fo llo w in g te c h n ic a l g u id e -v a lu e s fo r c h r y s o tile a s b e s to s are given in order to e sta b lish a b asis fo r the p ro tectio n a t th e work p la c e w ith te c h n ic a l m easures and g u id an ce:
C hrysotile fine dust
0.15 mg/m^
Tine d ust containing c h rv so tile
4.0 mg/m-3
QL l0* w? / V
STANDARDS FOR ASBESTOS DUST CONCENTRATION FOR USE WITH THE ASBESTOS REGULATIONS 1969
In this note guidance is given on how HM Inspec tors of Factories will interpret the expression `dust co nsisting of or containing asbestos to such an extent as is liable to cause danger To the health of employed persons' and how the measurements may be made. It is emphasised that these notes have been prepared for the guidance of HM Inspectors since only the Courts can give binding decisions in these matters. It is im portant to bear in mind that these standards are provisional and may have to be revised from time to time.
Chrysotile, amosite and fibrous anthophyllite
In cases of doubt c onfirm ation may be sought from any organisation with X-ray diffraction equipment e.g. colleges, universities or analytical laboratories. W here difficulties are experienced assistance should be sought from the Industrial Flygiene Laboratory of HM Factory Inspectorate.
NOTE 1 " fibres" /cc means particles of length between 5 m ic ro n s and 100 m icro n s and having a length to breadth ratio at least 3:1, observed by tran sm itted light by means of a microscope at a magnification of a pproxim ately 500x.
2 m g / m :! means m illig ra m m e s per c u b ic metre.
(a) W here the average concentration of asbestos d u s t over any 10 m in ute sa m p lin g period is less than 2 fibres/cc o lJ L I m g/nv\ HM Factory
' InspectorahTwill not seek to enforce the sub stantive provisions of the Regulations, in particu lar re g u la tio n s 7 and 8. W h e re the co n c e n tra tio n is 2 fibres /cc or 01 mg /m 3 or more (but not mote than 12 f i b r e s / c c or 0 6 mg / m 3) fu rth e r s a m p lin g over a fo ur hour period will be carried out to deter mine whether the average concentration of as b estos d ust still exceeds 2 fibres /cc or 0 1 mg /m '.
(b) W here the average concentration of asbestos dust over a four hour sampling period is 2 fb ro s /c c or 0 1 m g /n f! or m oie the extent to wh 1 HM Factory Inspectorate will requite the s ta ;ird to control to be improved will depend upon the am ount by w hich it exceeds 2 fibres,/cc or 0-1 m g / n r ' and the d uratio n of exposure.
(c) W hen the average concentration of asbestos dust over any 10 m inute period exceeds 12 f ib r e s /c c or 0 6 m g / n r 1, In s p e c to rs will norm ally seek to confirm or otherwise the accuracy of the test by means of a further sample before taking action to enforce regulations 7 or 8 whichever is appropriate.
Crocidolite
The Regulations will apply in full wherever workers are engaged in processes involving crocidolite because the concentration of this mineral that is believed to be liable to be dangerous to health, is very small indeed. A n approved Torni of respirator will be required to be worn unless the concentration in the breathing zone of a worker in a crocidolite process can be m aintained below 0 2 fibres /cc or 0 01 m q / m :i when m easured as the average c o n ce ntratio n over a 10 m inute s a m p lin g period. In s p e c tors will normally seek to confirm the accuracy or otherw ise of the test by means of a further sample before taking action.
C ro cidolite can usually be recognised by its rich lavender blue colour, although discoloration should he expected in the inner layers when used as an insuinnt on very hot surfaces.
Sampling--general considerations
There should be an awareness of the philosophy of dust sampling before attempts are made to carry this out and a knowledge of the inherent difficulties in the interpretation of the results obtained. The concentration and composition of the dust environ ment of a worker will vary within wide limits through out his work cycle so that it is often difficult to choose representative intervals if discontinuous sampling methods are used. Clearly, the longer the duration of each sample and the more samples that are taken, die more accurately will the average exposure be determined.
Short period samples will be taken over a ten m inute period by means of an |n<'*! u~ien[ with its inlet placed in the im m ediate breathing zone of s worker engaged in a process to which the Regulations may apply. Inspectors will choose the sampling period to coincide with a period of maximum dust generation. Sampling over the period will be c o n tinuous or at regular intervals in the case of use of manual bellows aspiration and the size range of the particles collected for examination by optical m ic ro scope will not be deliberately restricted.
Portable continuous sampling equipment carried on the worker may be used in many circum stances as it is th o u g h t that in general this will be less likely to lead to error in determining average dust exposures. Four hour tests therefore may be carried out in this manner or by successive tests of shorter duration; alternatively where employment at a continuous process is itself continuous, for instance at a sp in ning frame, an array of continuous sampling static instruments set at head height about the mean working position may be used.
Analysis of samples
It is necessary to obtain a measure of the c o n c e n tration of the asbestos mineral of interest, not merely of the total minora! dust concentration, unless the concentration of the latter is less than the figures stated in paragraphs 2 and 3 of this note. The total dust concentration can be used for routine m onitoring purposes in a particular factory provided tit at acceptable evidence is available to relate1 tee total
* 4/
4
TECHNICAL DATA NOTE 13
i
x.;;.
Standards for Asbestos dust concentration for use with the
A sbestos R egulations 19S9
DEPARTM ENT OF EMPLOYMENT HM Factory Inspectorate
E*k'l/i '/
O
39. Not all the evidence points towards crocidolite only being concerned. Webster(22) has suggested that some other factor either alone or in association with asbestos, should be considered. In South Africa, although the chemical composition of the North West Cape and Transvaal crocidolites is similar no case of mesothelioma has been found in people exposed only to the Transvaal crocidolite. Production in the Transvaal however is relatively small compared with that of the North West Cape. American investigators<23) who have examined the relationship between exposure to asbestos and mesothelioma in the USA have stated that in the past crocidolite consumption there was a negligible proportion of the total asbestos consumption, leading them to suggest that mesothelioma is a neoplastic hazard of asbestos exposure and not necessarily a problem only of crocidolite. Wagner*24' of the Pneumoconiosis Research Unit, has produced experimental mesothelial tumours in rats not only with crocidolite but also with amosite and chrysotile. Amosite, to which crocidolite is closely related both structurally and chemically has not been associated with mesotheliomas in South Africa, its only commercial source of supply. However, the mining of amosite is more recent than that of crocidolite and it may be that insufficient time has yet elapsed for the development of mesotheliomas due to this fibre.
40. At a meeting following the Symposium on Biological Effects of Asbestos in New York in 1964, the Working Group on Asbestos and Cancer of the Inter national Union against Cancer expressed its views on this extremely difficult problem in these words: "In the case of mesotheliomas evidence from certain countries suggests that exposure to crocidolite may be of particular importance but it cannot be concluded that only this type of fibre is concerned with these tumours and further investigations of this problem are needed" *25'.
41. These words aptly sum up our own views on the aetiology of mesotheliomas.
However, we feel we must go a bit further and pose the question "Can we in the
light of the existing evidence incriminating crocidolite afford to wait, perhaps
for several more years, until pure population studies give a final answer to this
problem?" This we appreciate is not solely a medical question, but we feel it
is within our competence to recommend that, unless special considerations
operate, crocidolite should wherever possible be replaced by another variety of
asbestos and whatever measures mav be arionted to control asbestos dust, these
'must be even more rigidly applied to crocidolite.
""
Medical supervision and examination of workers exposed to asbestos
42. The Report*2' by Merewether and Price recommended "the control of the disease by periodical medical examinations of the workers by which those unfitted by health reasons are prevented from entering the industry, and cases of fibrosis and pulmonary tuberculosis are detected at the earliest possible moment. The ultimate and only reliable test of the effectiveness of the preventive measures adopted in the industry will be found in the statistics derived from the records o f periodical medical examination of the workers . . . " . The Asbestos Industry Regulations and a scheme for initial and periodic medical examinations with provision of compensation within the Workmen's Compensation Acts for those asbestos workers with asbestosis shortly followed.
21
'""'W PWPIMli p . Hum
mm
DEPARTM ENT OF EMPLOYMENT AND PRODUCTIVITY HM FACTORY INSPECTORATE
Problems arising from the use of Asbestos
M E M O R A N D U M of the Senior Medical Inspector's Advisory Panel
JIJ1S 1 9iF 'V . KLDi/sAN MINES LTD*
L O N D O N : HER M A JESTY'S STA TIO NERY OFFICE PRICE 3i. 9d. NET
L -U
ship undergomg repair or refitting: the heavy bags of saturated asbestos may
be too cumbersome to carry through restricted openings and up steep flights
of steps. Full advantage must therefore be taken of all other precautions.
Dust extraction must be as effective as possible and, in the selection of tools
for removing the lagging, preference should be given to those producing
least dust. It is understood that progress is being made in the development of
stripping tools incorporating dust-extraction equipment. When lagging has
to be removed in a dry condition the laggers may have to be provided with
the highest standard of protective equipment--heavy-duty, impermeable
overalls with head coverings and air-line breathing apparatus connected to a
supply of clean compressed air. This is particularly important when the old
lagging is crocidolite or `blue nsfiestoi?' '
.....
In addition to tne laggefs\)fher wo^rTs'ers in the vicinity of lagging operations
and exposed to the dust should wear protective equipment. The area over
which this precaution is needed should be roped olf and signposted. If
possible lagging and delagging operations should be carried out at times
when other workers are not in the vicinity.
When each stage of the work has been completed the floors, walls, fixtures
and plant in the area should be thoroughly cleaned by a w;et method or by a
vacuum cleaner or by both. Where this is not practicable, the Regulations
allow' cleaning by other methods but in these cases protective equipment must
be worn (Regulation 11).*
As substitutes displace asbestos in this process the risk will diminish, but
^forjm an^x^ars^^lcR^^
have to be stripped--sometimes in
precautions will have to be
scn m u lo u slv o fiseiw e(F ^/fien ^oTcnagging containing crocidolite (blue
asbestos) is being stripped, the District Inspector of Factories must be
informed (see Regulation 6).*
ASBESTOS SPRAYING
In the construction industry asbestos is applied by spraying techniques to open steel work, walls and ceilings for the purposes of fire protection, thermal insulation, acoustic damping, condensation prevention and corrosion in hibition. The material employed for the process is usually a powder con sisting o f a cement and a sF e ^ o smixture, but sometimes the mixture consists oWadhesive resin and cement. These preparations are incorporated with water in various types of* pre-mixing machines and spray-guns and are thus applied to the surfaces in the form of an aqueous spray.
The nature of the spraying process and the circumstances in which it must be performed conduce to a serious contamination of the environment and very positive steps must be taken to reduce it. This contamination may be caused by overspray when surplus material falls to the floor in quite substan tial quantities, or the air in the vicinity of the spray may be directly con taminated by a haze or mist which contains minute asbestos particles. The atmospheric contamination arising from this cause can be greatly reduced by using a pre-damping technique which moistens the asbestos fibre before it is
*Appendix
16
x/lst * * #***<**
fed to are dr reduce
The charge be ert opera' dbris waste thus i when draug areas
Jn t made from ordin; meant used, in red drips the sp effect breatl provk educa to ob;
Arr when workc has u this p they a
The asbest whicli
FIT' BUI
A cor asbesi are us these and f situt plant
*Appe
HEALTH HAZARDS
Asbestos, however, is a dusty substance and it is unfortunate that the dust of this very useful mineral can be highly injurious to those who inhale it in sufficient quantities. The danger came to light with somewhat disconcerting "suddenness m the second half of the nineteen-twenties when it became apparent that asbestos could cause a specific fibrosis of the lungs which was named `asbestosis'. A few years later it was suspected that asbestosis might be complicated by the development of lung cancer, a suspicion that was confirmed some twenty years later by the investigations that were conducted during that period. Still more recently a relationship has been demonstrated between exposure to certain tvnes of asbestos and the occurrence of mesothelioma, a cancer o ft he pleura (the lining of the lungs) or of the peritoneum (the lining of the abdominal cavity). Whereas asbestgjis^and the ffin^gncer associated with it have only arisen in workera^nflLAayg--bgen_gj^sed for years toj^eavylconcentrations of the dustin_asl2Si23factories or in pro cesses in* whicn "asbestos is used, mesothelioma nas developed in some individuals with short periods of exposure. It is still a rare tumour among the general population but not uncommon among those exposed to asbestos dust. Crocidolite may be more dangerous in this respect than are the other formsofaso!
INDUSTRIES
The circumstances in which danger arises from exposure to asbestos dust are thus established. The minerals that come under consideration are those that have industrial significance, namely chrysothe, crocidolite, amosite and anthophyllite, although the last of these has a limited use in this country. The diseases are asbestosis, lung cancer and mesothelioma. The industries are those in which asbestos is processed in the manufacture of a number of products and those in which the products are handled in such a manner that dust is evolved. The great variety of industrial activities, other than those of the asbestos factories themselves, in which asbestos and its products are used, is indicated in the following table abstracted from the Memorandum of the Senior Medical Inspector's Advisory Panel on `Problems arising from the use of Asbestos'.*
TABLE
(1) Factories in which asbestos and its products are used:
Electricity generating
lagging and de-lagging
Steel lagging and de-lagging
Heavy engineering
furnace insulation
> Loco building
1
Railway carriage building /
heat and sound insulation
`Problems arising from the use of Asbestos', Her Majesty's Stationery Office. Price 3s 9d
(4s Id)
4
Bofler making Paper
Linoleum Floor tiles Rubber Paints Plastics Adhesives Roofing compounds
Motor assembly
Motor vehicle repair Building trades
Scientific Light engineering Electrical engineering
heat insulation manufacture of filter papers and grinding
of rollers
used as a filler
J
incidental grinding in assembly of brake and clutch parts
repairs to brake and clutch parts trimming of asbestos/cement sheets and
insulation boards; asbestos spraying insulation making of asbestos washers and gaskets insulation systems
(2) Contractors carrying out work involving use of asbestos may be found in :
Dockyards Shipbuilding Shiprepairing Generating stations Installation of plant in heavy industries e.g. steel Large building projects--industrial and domestic--
on insulation and repair of heating apparatus e.g. in schools
(3) Other asbestos exposures may occur in:
Certain aircraft maintenance activities Disposal of asbestos/cement waste which may be used e.g. as
hard standing in car parks Car body underseals Asbestos/asphalt mixes for road surfacings
SUBSTITUTES
In the search for safe conditions for a process in which a harmful substance is
used, consideration should first be given to the possibility that a safe or less
harmful substance may serve the purpose of the process. The physical and
chemical properties of asbestos have been of such outstanding value for
many technical purposes that alternative materials have not been readily
found which would serve a particular purpose as well as asbestos. Sometimes
the^^sTTrarmfu^
but the
propertiesyTttr^everaT^inerals tailing withmTheaesignationofasbestos are
not all exactly the same. While the resistance*ol chrysoTiTe"T?m^ensrT[ear7s
good, that ol crocidoITte is relatively poor and it tends to fuse at high temper
ature; on the other hand the resistance of chrysotile to acids is poor while
HSW 44-- c
5
