Document LgnqDGyKV2Xn59xamkL31LwGq
FILE NAME Manville JMA
DATE 1966-1968 DOC JMA229
DOCUMENT DESCRIPTION Manville & Knowlton Services
1966-68 Report & Letter
TO
H. M. Ball
W. P. Gibbons
Roger Hackney
C. W. Hite
H. M. Jackson
A. B. Marchant
G. H. Martens Jr.
K. Lindell
W. P. Raines
K. W. Smith A. C. Smith
M.D.
A
May 31 1966
CC
C.B. Burnett
F. E. Dutcher
D. L. Hinmon
F. H. May Jr.
R. F. Orth
J. L. Allen
vA
W. F. Goodwin
R. F. Knapp G. D. Murray
C. L. Scheckler
Yvan Couture - Asbestos
T. S. Patterson - Toronto DH
Carl Thompson Hill and Knowlton
BACKGROUND FACTS ON THE
ENVIRONMENTAL HEALTH ASPECTS OF ASBESTOS
Each of us is exposed each day to the possibility of questions
from within or outside the company regarding the various aspects
of asbestos and public health As you know we developed a position statement in the form of questions and answers at the time of Dr. Selikoff's March 1 publicity release Now that several
additional attacks on asbestos from other sources have occurred
it seems well to date it
Accordingly we worked with Hill and Knowlton and Dr. to produce the attached statement that is recommended
Kenneth for use
Smith for
Con't
Page -2-
May 31 1966
the time being
As you will see this statement does not contain any new
ammunition for use in rebutting criticism there simply has not yet been time to develop such ammunition from the literature search phase of our current activity However the wording is dated to reflect the two most recent public attacks We'll update and issue as additional facts come to our attention
If you have queries from the press please refer them to me or in my absence to Bill Raines Director of Public Relations or Jon Allen Manager of Press Relations
fjs
att
F. J. Solon Jr.
INTERIM POSITION STATEMENT
For use in reply to possible queries
REVISED 5/31/66
ENVIRONMENTAL HEALTH ASPECTS OF ASBESTOS
The following may be attributed to Dr. Kenneth W. Director of Manville Corporation
Smith
Medical
GENERAL COMMENT
No one really knows what
testimony which points a
causes
finger
cancer Therefore any medical at a potential suspect is under-
standably of interest and concern to the public
As an asbestos producer Manville
tions and maintains thorough records on
M records do not indicate that cancer
conducts medical examina-
the health of its employees occurs any more frequently
among the employees at the company's asbestos mines and asbestos-
processing plants than among the general population
With regard to claims of exposure of the general public to the
inhalation of asbestos fibers as a result of their use in
ceiling and evidence is
floor tile available
brake linings etc.
Asbestos is not one
very little scientific but a variety of
different minerals It is important that objective scientific
studies be made to determine whether any of the various types of
asbestos present potential health hazards to miners workers
users or the general public
To that end Manville and the Asbestos Textile Institute
have been cooperating Service in a study of
since 1963 with the U. the asbestos industry
S. Public Health
The study is being
headed by Dr. Lewis Cralley of the Public Health Service
Manville is a member of the Quebec Asbestos Mining Associatio
which is also sponsoring a program of medical research on possible
effects of asbestos on workers who mine and process it
Con't
Page -2-
COMMENT IN REGARD TO DR SELIKOFF'S FINDINGS
Reference by Dr. Irving J. Selikoff to an elevated incidence of cancer among those exposed to asbestos dust is based on limited reports relating to a relatively small group of workers who install and remove a variety of insulation materials including
some which contain asbestos
COMMENT IN REGARD TO THE OF THE ARCHIVES OF
ARTICLE IN THE MAY
PATHOLOGY A.M.A
ISSUE
Recent articles speculating about asbestos as an air contaminant call for emphasis on the scientific limitations by the authors
themselves
For example the article just published in the May issue of
ARCHIVES OF PATHOLOGY of the American Medical Association refers
to finding scanty asbestos in some of 500 autopsies performed Yet the authors specifically state that none of the subjects had pulmonary disability and all died from other causes The authors do pose some questions they say deserve study
CARL THOMPSON
HILL AND KNOWLTON INC
Public Relations Counsel
150 EAST SECOND STREET
'
NEW YORK 17 N.
OXFORD 7-5600
October 7 1966
Mr. F. J. Solon Jr.
Vice President
Manville Corporation 22 East 40th Street
New York N.Y. 10017
taeka Dear Jack
ea The reference to the symposium I mentioned yesterday by phone came from Gershon Fishbein's Environmental Health Letter which said as
Te
follows
seal
ASBESTOS PNEUMOCONIOSIS SEMINARS COMING UP
tiem
ab
- Much concerned with the problem of asbestos and its
DD
a
effects on workers the Public Health Service's Division
mek
of Occupational Health will sponsor a seminar on the sub-
ject Dec. 7-8 in Cincinnati to bring up to date some of
the information which has been accumulating recently
Of particular concern is the reported increased incidence of mesothelioma associated with extensive exposure to asbestos fibers The Pennsylvania Department of Health is reportedly investigating some clusters of cases in neighborhoods near factories using asbestos or fibers
Since this has received public distribution I see no reason not to have our Washington office check further and am asking them to do so
The other item about the Pennsylvania Department of Health is of
significancteo you and we know that there have been some recent
references to studies done around Lancaster Pa
Sincerely
ret
e
sdd
die
wen
es
amt
Se
Thompson
Carl Thompson
- Draft 8/12/66
7
oe
Y
Asbestos and Human Health
industry The march of modern
brought with it many previously '
unsuspected health hazards to those opposed to various substances
>
----
achieve maximum protection to workers , industrial medicine has become
an important part of industry a distinct branch of medical practice ,
.
_ and a function of public health authorities at all levels of government
Industry has a continuing role in protecting the health and safety
of its workers and the users of its products
In the asbestos industry -- mining and fabricating -- an industrial health hazard is asbestosis , a recognized disease of the lungs known to
40 medicine for years Asbestosis is discussed in some detail elsewhere in this brief At this point it is important to note the following facts
Modern methods of industrial hygiene mines and factories
have reduced asbestosis to the point where it is no longer considered
a common health hazard for workers
Ceth Ceth
. Asbestosis only occurs after prolonged and excessive occupational
exposure which is now generally controlled
o
. Because of its long history the medical literature on asbestosis is extensive and both prevention and treatment are well understood
Recently however there have been published in medical journals
and the lay press as well suggestions that
with exposure to asbestos
lung cancer may be associated
|
The implications of these suggestions are naturally of great
concern to the asbestos industry The industry is concerned with the
health of its own employees -- asbestos miners and fabricating workers
ry
2-
Q
_
In addition there is concern also for workers in customer industries -- |
asbestos insulators and construction workers
who might use
Finally
the suggestions involve the health of the general public , however slight
may be their exposure and however remote
disease may possibility exposure might lead to
be the
that such
In the past 20 years the condition of lung cancer has received
.
gre
increasing medical and public attention because the reported mortality
aa
.
from lung cancer has increased substantially in numbers
|
It is generally
|
_
conceded however that at least a part of this reported increase is apparent - >
rather than real That is it results from expanded knowledge of cancer
; tremendously improved diagnostic techniques and procedures and what a
prominent and respected medical journal has called greater lung cancer
consciousness among doctors Furthermore even part of the lung
cancer increase is due to more people living longer as a result of the
greatly decreased mortality from other diseases , particularly infectious diseases Fewer people die young of tuberculosis for example they survive
to reach cancer old age
In any case the reported increase in lung cancer cases has
resulted in serious and laudable efforts to identify the cause or
causes It is natural and rational that all substances inhaled into the
.
;
|
lungs should be among prime suspects Cigarette smoking has received
_ most of the attention and blame , although general air pollution has also
Uranium mining apparently increases risk been widely accused
lung cancer In the search for factors that may be involved asbestos
dust was inevitably added to the list of substances to be studied
among Unfortunately the tendency particularly
laymen has
te
ea
been to equate investigation with incrimination and there are some
oman
tens
en
-3-
believe who tend to
a suspect is guilty until proven
innocent innocent until proven guilty "
-- not
~
A few hundred years ago it was generally believed that maggots
were spontaneously generated by the
Repeated rotated around the earth +
heat of the sun and that the sun observations seemed to confirm these
| po
beliefs )
mequelon
mequelon
mequelon
P
and
* believed A little over a hundred years ago it was
yellow fever were caused by the miasma -- or bad air --
that
from
cholera
swamps
Misty years ago pellagra was thought to be an infectious
disease observations on which these medical beliefs
relatively were in their timetime ,
based were
disease
sophisticated erroneous but the conclusions were as
as the theory
The
of
earth the sun spinning around the
!
These theories could not be
confirmed by experimentation aud experimentationand were eventually disproved by
experimentation Suggestions associating lung cancer with neither asbbeystos been confirmed nor disproven by experimentation nor
have
many observations
aud
aud
conference conference
of asbestos workers Without such support the subject should be
conference
conference conference
regarded with scepticism at the present time
The fact that the question has been raised however has resulted
evidence in increased studies to collect
necessary e of what the facts are
to make a determination
a
=
:
ere
I. What is Asbestos
Any attempt to assess the effect of asbestos on health is
fact complicated by the
that asbestos is not a single chemical or |
;
physical entity Asbestos is a name given to a group of minerals not
_ to one particular mineral The two major groups of these minerals ,
pyroxene asbestos and amphibble asbestos comprise various types chrysotile
amosite crocidolite
, anthophyllite tremolite , actinolite brucite and
picrolite
In the United States chrysotile amosite and crocidolite are
used for different kinds of products , but chrysotile is by far the most
common About
of the asbestos
XX used country principally from mines in Canada
in this
is chrysotile
Each of these types of asbestos differs from the others ,
chemically and physically To add to the complexity there are at least
|
five different varieties of chrysotile each with a distinct chemical
a
composition so that the product of one Canadian mine is not identical with the product of another Canadian mine
In recent years some of the writers on asbestosis have become
aware that there is
they have attempted
have been exposed
|
significance in the to specify the type
.
different types of asbestos and
to which asbestosis victims may.
_ Such differentiation has not been as clearly observed by those
who theorize on the asbestos cancer association Their writings
e
te
tend to speak of asbestos generally ignoring the very real and important
e
differences among the various types and indeed disregarding the distinct
e
have possibility that the subjects of their studies may not
been exposed-
_ to asbestos ofany type whatsoever
WY
three Each of the
most important types of asbestos chrysotile,
amosite and crocidolite, exhibit distinguishing characteristics
Chrysotile - By far the leading producers are Canada and the
Soviet Union Smaller deposits are found in Rhodesia China and the
United States Chrysotile a pyroxene asbestos , occurs where areas of ~
subsequently serpentine rock have been cracked by earth movement and
reacted by hot volcanic waters under intense pressure This reaction
transforms the granular serpentine into fiborous chrysotile Chemically
chrysotile is hydrous magnesium silicate with a positive electrical
charge Because of this positive charge chrysotile can be attacked by : acids Commercial fibers contain small varying amounts of iron and
titanium
.
. Crocidolite - The bulk of the world's supply comes from
South Africa although there are small mines in Australia It is an
amphibole asbestos occurring in rich sedimentary rock Chemically
. crocidolite is a ferrous sodium silicate with a negative electrical
characterized charge
a
It is
by a very deep blue color
. Amosite - The Transvaal district of South Africa is the
only place where amosite is found It is a member of the amphibole
asbestos family occurs in the same type of rock as does crocidolite
and has the same negative electrical charge Chemically amosite is a
ferrous magnesium silicate
With these basic differences it might be expected that the three-
types of asbestos would vary in biological effect and numerous observations
confirm the expectation There seems to be broad agreement that chrysotile
. the most common type in use in the United States , is least likely to
produce asbestosis as result of exposure
fm
re eg
ee
ee
ee
types There is no proof that any of the three
of asbestos
produce cancer produce lung
in animals or in man But in any case it should
RedReodo
be remembered that data may implicate say crocidolite can not be
assumed to apply to amosite still less to chrysotile
|
|
Wagner ( ) experimented with three types of asbestos
>fl
'
/ fhe on various laboratory animals and found that crocidolite produced i the most severe reactions and that amosite was more than five times
f
Ek
as irritating as chrysotile He reported in 1963
.
/ , oa
tes
'. .
'
.,
With chrysotile dust it was possible to produce
in the lungs of guinea slight fibrosis in
severe lesions
effect was observed in two rabbits
monkeys while no significant
Amosite dust causes marked asbestosis
in all three kinds of animals Lesions occur more rapidly in guinea exposed to this dust than in those exposed to chrysotile There is
indication that the disease is progressive in monkeys and rabbits an
Similar pathology to that which occurred in
:
for 22 months was observed in
a monkey exposed to chrysotile ..
a monkey exposed to amosite for four months
The impure crocidolite dust caused severe disease in
,
the rate of respiratory infection among animals
guinea and
more marked than with the other types
exposed to this dust was
It is possible that this may be
due to the high quartz content of the dust -
.
.
| ;
J of
Finally asbestos bodies could be demonstrated in the lungs
;
animals exposed to all three types of asbestos dust These were
:
scanty in the animals exposed to chrysotile and usually segmented
i
Only occasional fibres were observed In contrast to this the asbestos
bodies in the animals that were dusted with amosite
and
segmentation was
rare
fibres were
were plentiful extremely numerous and far
outnumbered the bodies
:
-
e w
8
_
_
;
; '
27
oe
Meda
ey
Be
oda ne
. emc
sw
.
me
we
ak
7
ne
as
}
Following further investigation Dr. Wagner offered an
explanation for this observation at a medical symposium (
7
) 1965
e
A method of producing asbestos dust clouds has been devised .
and an animal inhalation experiment carried out to test ... - The elimination
rate of Rhodesian chrysotile has been found to be three times greater .
than that of the amosite and crocidolite which suggests an explanation
for the previously observed reduced fibrogenicity of this dust difference in the elimination rate remains to be determined
The reason for
the
,
i +
of
of
Ot
-7-
me
cere
ns
ereta
--
At the same meeting Schepers ( ) expressed doubt whether any
ne
eee
ey
oe
of the reported lung cancer cases claimed to be associated with previous
prema asbestosis could be identified with chrysotile exposure
Gar
en
2
me
My first impression is that there now is less certainty that asbestos inhalation is associated with pulmonary neoplasia than there was ten or twenty years ago Perhaps this is due to the greatly
ees
come
ce
4 oes ,
reduced dust exposures Asbestos may after all prove to be carcinogenic
ce
only in overwhelming dosage Thus the high prevalence of neoplasia
we
which was reported several decades ago may be a function of the severity
ee
of exposure rather than an indication of high carcinogenic potency
sem
carcinogenicity I suspect that in final analysis the
be rated as of low order
of asbestos will
.
*.
vee
_
ay
Finally there is the question of whether inhalation of
chrysotile is associated with neoplasia On critically reviewing the
work histories of eleven cases of lung canceirn chrysotile workers
I find that all of these had at one time or another also been
exposed to other forms of asbestos mainly amosite or crocidolite
Their predominant exposure was to chrysotile but since there is such
strong evidence incriminating amosite as a carcinogen the fact that thes-- .
men also had been exposed to amosite is disruptive of a
chrysotile se theory : of
per
() .
5
of carcinogenicity
II What is Asbestosis
.
Asbestosis , first described
derscribedesul1ti9ng24 diseases called the pneumoconioses ,
is one of a class of
diseases which requet
when excessive quantities
of dust are inhaled over a long period of time True asbestosis is
characterized by the presence of particles of asbestos lodged in the
lung, so that the surrounding lung tissue becomes fibrous Clinical
symptoms arenot always present but in its severe form asbestosis is
disabled may accompanied by breathing difficulty and in such cases the victim
be
|
y,
lung 1 Q.
of great
cancer is the
relevance fact that
to the alleged link between asbestosis and
15
diagnoses of asbestosis itself are still
uncertain Despite the undeniable existence of the disease and its
a ren eee
,
.
extensive literature even the most experienced physicians have difficulty
Lf . on, fs
ofes
in distinguishing asbestosis from other pneumoconioses and even from
yt?
completely unrelated chest diseases
The situation is made more complicated by the fact that
pneumoconioses dusts are sometimes caused by a mixture of various , .
silicasilica col cement or sticstic
such as cement carbon silics If lung disease patient has been
exposed to mixed dust lives in an polluted city and is a heavy smoker
how accurately can specific of his disease be determined
Much more common than asbestos is silicosis caused by the
inhalation of stone dust Silicosis has been proven to be associated
with tuberculosis On the other hand all evidence to date supports the
view that there is no association between asbestosis and tuberculosis
Furthermore silicosis is progressive while asbestosis is static The
disease only gets worse through continued exposure to asbestos dust Finally there is a difference of opinion among scientists as to whether
090
the lesions induced by asbestos in experimental animals is identical with human asbestosis or merely resembles the human disease -
The difficulty of diagnosing asbestosis was pointed out by
Sander ( ) in 1955 who cited some of the confusing symptoms and
reported the varying diagnoses made by a group of physicians in
examining ray films
All these examples I assume represent patients who present
themselves to their physicians with symptoms of dyspnea with a
bt history of some exposure to asbestos dust and with chest films of the
..
character I have mentioned How easy it is to fall into the trap of a
,
_,'
gunshot misdiagnosis Unless other possible causes for the ray
es
changes are considered first and a detailed past occupational history is
eo
' evaluated along with the character and extent of the most recent dust
exposure another worker who actually needed reassurance will be told that
his lungs are full of asbestos dust and that he should quit his trade
. From that point on his symptoms usually increase to a marked degree , and
<
he has developed what to him is a real disability In my experience such
.
induced disability is commoner in some areas than is the disability
from the disease itself
_
... number of my films from the textile mill in North Carolina
for which I am consultant representing cases which I had classified as
early or first asbestosis were called essentially negative by a number of physicians present who had had long experience with this disease
The reverse also was true some films I had called negative which others .
thought represented stage asbestosis The same disagreement was
found with the other films which were presented It was our final
conclusion that and that it can
the next by the
it is impossible to clearly define a first case be called essentially negative one day and first stage same reader This was not new It has been emphasized
repeatedly by Pendergrass beginning in 1938.
A similar experience was reported in 1960 by Williams and
Jones ( ) who took 38 ray films of asbestosis patients and mixed in at random films from nine patients with other chest diseases ,
and six normal chest films The films were then shown to two panels of
radiologists and chest specialists who were asked to interpret them
The authors wrote
-10-
\
There were several surprising findings in this study One
+.
was the extent of the disagreement between the observers in the diagnosis
a
es
on
of the films from the certified cases of asbestosis These patients had
.,.
T
Ce
;
.. all been seen and certified by the pneumoconiosis medical panels and
,
*
had initially been selected by us as classical examples of the disease
Yet when the same films were viewed in the present trial the number
s
, . Oo to show changes consistent with the diagnosis of asbestosis varied thought
from 40 to 80 approximately according to the observer
*
.
11
widely mo
... conclusion it is apparent from the observers
: 6
tn ee pee
in the group of films from other
findings
ed
'
appearances in asbestosis
pulmonary diseases , that the radiological
x .
are by no means specific , and may be confused
with such
differing diseases as chronic bronchitis and
.
rn _ sarcoidosis and other pneumoconioses Presumably if other inteemrpshtyisteimaal
_
fibroses such as scleroderma lymphangitis carcinomatosa xanthomatosis
+
_ or beryllium granuloma had been included in this group the confusion ,
_ would have been even greater
eee
,
st
.at a
The situation has been summarized by Demy 1962 ( )
a emp ere tt ee ee
there is no specific radiologic ray diagnosis of
pulmonary asbestosis and the picture of expertness and infallibility with which lawyers like to introduce their particular expert medical
witness is a legal fiction to impress the jury Lawyers should be introduced to the Second Aphorism of Hippocrates , who writing on ancient medicine stated Whoever , having undertaken to speak or write
to . on medicine have first laid down hypothesis
are clearly mistaken in what they say
their argument
Sincer the diagnosis of asbestosis is so often questionbale|
a diagnosis of asbestosis accompanied by lung cancer must be even more
questionable since diagnosis of primary lung cancer is still an
uncertain art
|
Questions
.
.
|
feature Questions Another
of asbestosis which negates
the lung cancer
association WriWtritee asbestosis es is the progressive nature of the lesions of
e The malignant feature of cancer is its ability to spread while asbestotic
wee
/
fibroses are limited to the area of the included asbestos particle
prema
Experiments conducted by Vorwald et al ( ) revealed that the
fibroses produced in animals by exposure to asbestos dust do not spread
or
become worse
The authors said in 1951
.
|
ed
-11-
pulmonary reproduce
which are
disease Although in man asbestosis is a chronic
with diffuse .
fibrosis which
in one or more similar to the
requires years to develop it is
species of animal characteristic
lesions of human asbestosis
possible to
tissue change's
in Long asbestos fibers are essential the production of
ae
the peribronchiolar fibrosis short fibers are incapable of producing
this reaction
BO!
Sop
The mode of action of the long asbestos fiber in the
wo production of asbestosis is primarily mechanical rather than chemical
in nature
discontinuance ... Established experimental asbestosis ceases to progress on
.
of dust exposure
The experimental investigation shows in fact that on
discontinuance of exposure there was an appreciable clearing of the mature
pulmonary lesions due to contraction of the fibrous tissue
Gross and Smith (
_
) compared the progressive nature of
asbestosis with progressive silicosis suggesting that the explanation
might be found in the contrast in shape between the long asbestos fiber
and the round silicon particle Their paper published in 1959 observed
In contrast to silicosis asbestosis is not a progressive
disease Basically silicosis owes its characteristic progressiveness to
'. the fact that silica particles deposited in one site may be transported
by tissue fluid generally as edema fluid to uninvolved portions of the |
lung to initiate new lesions Asbestos fibers in contrast cannot pass the intricate barrier presented by the lattice work of tissue fibers as
; readily as particles of the same diameter which are substantially spherical
. Also since asbestos has a very considerable solubility dissolution of the fibers offers a plausible explanation for the paucity of mineral
found in asbestotic scar tissue Both of these factors prevent the
transport of significant amounts of asbestos fibers from their site of
deposition to new locations and therefore explain the progressiveness
of asbestosis -
si;
?
:
7
-
EN eS EL
a
ee
.
Pr
oe
ee ee,
The causing potential of a substance is usually tested
ae
.
through animal experimentation in which a clear dose relationship is
demonstrated Animals exposed to heavy doses of the carcinogen over
.
long periods of time usually develop cancers Those more lightly exposed --
either in time or dose -- may show no signs of malignancies
-12-
; :
- .
Asbestos
has
|
produced
lung cancer
laboratory
animals animals
animals
There Furthermo
seems to be no
relationship for -
Ay clear time a
asbestosis in humans
Y Kleinfeld et al ( ) have remarked on this lack of correlation
between exposure and pulmonary disease
o=
The study group comprised 56 asbestos workers They were
:
selected on the basis of having had an exposure to asbestos dust
as asbestos insulators for 14 years or more and no previous occupational
dust exposure
11
.In
general
the
correlation between
the
degree
of
a
Sept
function impairment and the clinical and roentgenographic
at
pulmonary
as a whole and no consistent
findings was poor for the exposed group
To
be found between the duration of exposure and
correlation could
lung function impairment this group The lack of a good
correlation between the degree of pulmonary function impairment and the
:
clinical roentgenographic and environmental findings observed in the
present study has also been reported by Bader et al
a
=
;
oo
The comment of Gross ( ) in 1963 on lack of evidence is appropriate
-
proofthe association of pulmonary carcinoma
-
.In recent years
of many publications It seems only
with asbestosis has been the topic
for the establishment of
proper to expect the same rigorous critericaancer and asbestos as
etiologic relationship between pulmonary
is caused by
have been demanded for the
that pulmonary cancer
_ excessive cigarette smokin.g .
.
a
-
, Se
on .
e
Pew
-13-
III
What is an Asbestos Body
Asbestosis is characterized by the presence in the lung of
inhaled particles of asbestos Although asbestosis is difficult to
diagnose in true cases of asbestosis the inhaled particles golden
brown in color symmetrical shaped up to 5 microns thick and
50 microns long will form tiny tissue growths called asbestos bodies
Apart from the problem of what type of asbestos may comprise
any given asbestos body the term has gradually been extended in use
. to apply to any similar lesions found in the area of the lung which form
around a foreign body
It is known that many cases of pneumoconiosis are of mixed origin
xixi
A
Nevertheless some clinicians and pthologiswthso have reported the presence
.
of asbestos bodies have not employed chemical analysis This losse
identification has even been applied to particles found in the lungs of
xi subjects with no known exposure to asbestos whatsoever .
Ye Ne \
Pa
a
os
et
Cauna et al ( ) in 1965 reported the difficulty of identifying
Te
asbestos as opposed to other particles in a study of autopsied human lungs
.
4 \
ee
ee
Deter
es
:
The problem of absolute identification of asbestos in asbestos bodies is a difficult one and to our knowledge no successful histochemical
procedure has been devised Chemical examination of lung tissues for
'
acid insoluble residues yields a value for total silica that might
represent asbestos or other silicates No chemical determinations were
wD
-
done in these cases An attempt was made to identify the element silicon .
vet egameoo in asbestos bodies from a known case of asbestosis by electron probe
4,wer analysis Although iron was readily identified no silicon was
8
encountered The bodies seen in talcosis are identical to those in
asbestosis and are thought to be the result of contamination with tremolite
material ,,another fibrous silicate It is
associated possible are
with tremolite
that the bodies seen in our
-14-
er cert
7
. &
o
we
ve Bo
_
-
In a December 1965
symposium on asbestos ,
three experts discussed
the same problem of identifying an asbestos body Vorwald ( ) | |
_ stated
4
2
*
nme,
.
In view of my experimental and clinical studies of pneumoconiosis .
with special reference to asbestos and from the standpoint of the clinicalpneumocnios
pathologist looking at tissue from mortem material of the lungs
*
it would appear that a real problem is what is an asbestos fiber It Oe
seems to me that we must perfect techniques where we can specifically
oe
ot
identify an asbestos fiber as asbestos distinct from other fibers
present in the lungs that are not asbestos
Let us also recognize that not all bodies that we see in the lungs coated or uncoated contain an asbestos fiber There are
-{:
es
bes
hee
en
)
em
etry many bodies to wit the graphite body which is coated with ferratin
and iron which is segmented the bodies seen in worker's
pneumoconiosis the bodies seen in tremolite talc workers I have seen
A
the rouleux formation of degenerated red blood corpuscles which under oe
ordinary
stains often
as segmented asbestos
hematoxylin appear enu bodies
ere
ong
wes
And Holt ( ) added
Rae
eRe
.
eaten me
+ ROR
Again assuming that everything that looks like an asbestos
eevee E
8e
. body an asbestos body seems completely fallacious because in the literature
ge
you will find photographs of for example talc bodies The center is
me
-
es
not black I suppose that if there is a talc hazard this must be one
ee
. of the most serious ones because every woman when she powders her nose
surprised inhales very large concentrations of talc and I should be
there geneexrtraelmely T if
were not talc bodies in the lungs of women in
se
rte
ee,
:
The criticism of Schepers ( ) was directed at recent studies
OE
which have been given attention in the lay press
-15-
I am frankly astonished at the facility with which asbestos
ebesetn albonlgiasnhdetdhoroughly exposed to the dust and that might even have
the
pulmonary fibrosis I believe I am
:
consensus of experience of
quoting correctly
of asbestos bodies is both
pathologists in the U.S.A. that the findings
The superabundance of
rare and
in diseased lung tissue
always
;
significant
'
cases in Cape Town and
The suggestion that this
Miami therefore is a mystery
brakes does not
may be the result of abrasion of automobile
,
correlate with the prevalence of
driving habits There are
automobiles or local
an
in New York
more automobile brakes abraded per linear mile '
City than in either Cape Town or Miami If this is
:
factor I am sure Drs Selikoff and
the
have long since
Churg and other pathologists would
reported on this phenomenon For the time
despite
to
this
interesting
presentation
by Dr.
Thompson
I
being
am
and
continue to believe that the prevalence of
obliged
function of
asbestos bodies is a
hundreds of occupational exposure to asbestos dust I have examined
lungs of persons who never have been
industries and none of these has shown
employed in asbestos
have examined the lungs of thousands ofaesxbpeestroismebntoadliecsontLrioklewise I
ne
animals
Again asbestos bodies have never been detected in
hamster guinea pig rabbit cat dog or
a single mouse rat
monkey unless
a had previously been deliberately exposed to
such an animal
When I see my first unexposed subject with respirable asbestos dust
course revise my scepticism
asbestos bodies I shall of
-
an .
; .
.
.
_ -16-
i
i
i
|
{ IV
i
What is an Asbestos Worker
The opinion of Schepers is that the prevalence of asbestos
bodies is function of the occupational exposure to asbestos dust
Obviously asbestos miners and workers in asbestos fabricating plants fit
this category
It might be assumed that an Asbestos Worker the name applied
to a member of the International Association of Heat and Frost Insulators
and Asbestos Workers is also occupationally exposed to asbestos dust This may be true in some cases but it is not categorically true
Members of the called Asbestos Workers Union work with a wide variety of materials including different types of asbestos
Certain insulating materials contain amosite fiber and a magnesium
' silicate base others contain a mixture of amosite and chrysotile fiber still other insulating materials contain a mixture of these two fibers with calcined diatomaceous earth which contains a fair percentage of
cristobalite In recent years fiber glass has competed with rock wool
and rock cork Since workers tend to specialize in the installation of certain materials it is possible that many asbestos workers have never
been in contact with any type of asbestos fiber whatsoever Most reports linking asbestos to lung cancer have been based
on studies made among these asbestos workers who install various roofing
and insulating materials And in only a minority of lung cancer cases has there been reported concurrent findings of asbestosis or asbestos bodies in the lungs
17
xxxxxxx
The comment of Isselbacher et al ( ) made in 1953 still
| _
applies today .
Few reported cases of lung cancer related to industrial / asbestos exposures provide data on the character and quantity of dust
exposure This is a serious deficit in exact study of etiologic
correlation
-18-
V. The Health of Asbestos Miners and Fabricating Plant Employees In the United States and Canada reports suggesting an above-
average incidence of lung cancer with asbestos have not come from studies
_ conducted among those groups most heavily exposed On the contrary the
exposure of workers in the insulating trades where such reports have
Dele
Dele Dele
originated may be considered comparitively moderate at most and complicated by
exposure to other dusts and other factors This anamolous situation would
suggest that slight or moderate exposure to asbestos is more dangerous
on than heavy exposure -- a premise that is dubious
the face of it |
So far as is known employees of asbestos fabricating plants
^'Ai
positive in the United States with a
exposure to asbestos , and a
positive tendency to develop asbestosis , are no more likely to develop
lung cancer than the general population
Lanza ( ) commented in 1952
ome
11
...
some
of
the
mines
and fabricating plants
would dduusstt thhaatvsuepercviasinoncer medical supervision working extensively for over thirty years it
was a frequent complication of exposure to asbestos
.
would
have become evident long ago especially as the
supervision
asbestos workers is both thorough and comprehensive
Although no definitive study of the health of American
asbestos factory workers has been published as yet such a study is now being carried out by the U. S. Public Health Service
The health of Canadian asbestos miners however has been
studied the .
and
results show that the lung cancer rate among these
_ workers is not significantly higher than among the general population
tal,
ane2
The study was published in 1958 by Braun and Truan ( ) a.
According to the findings in this
from lung cancer does not
study the mortality rate
appear to increase with length of
exposure or
. with degree of exposure a fact which
the carcinogenicity of asbestos
presents strong evidence against
oo
that
Comparison of the experience among the asbestos
of various segments of the
miners with
shows
that
unexposed unexposed the observed number of
comparable
population
deaths among the miners is not
_
' significantly greater than the expected numbernumber
cases among the asbestos
The rate for proved
rate of 22.5 per 100,000 mfionrertshe 2r5e.s3t poferth1e00,000 compares well with the
for adult males throughout the Dominion of CaPnraodvai.n..ce and 20.8 per 100,000
... the basis of what are
date
it
seems
fair
to
conclude
believed to be
that the
complete
and reliable
- of Quebec do not have
asbestos miners in the Province
than do comparable
a significantly higher death rate from lung cancer _
_
segments of the general population
urbanized lower Furthermore ;
, the death rate from lung cancer in the
contiguous to the asbestos asbestos operations is
areas
widely scattered throughout the Province comparable to that in areas
than in some
of Quebec and is
.
areas within the Province
-
i
\
. ;
.
f
foe
evre
EY
add -
quotes
-
epidemiological epidemiolgical epidemiological date
ie
.me
me,
e
e
-20-
VI Chemical Physical and Biological Tests With Asbestos
In an effort to identify known carcinogens all types of
*
asbestos have been subjected to exhaustive chemical analyses Minute
traces of some suspect substances have been found but in such infinitesimal
scientists quantity that no significance is attributed |
studying
.
the question
.
In 1965 Goldblatt and Goldblatt ( ) commented on the fact
that the statistical observations on which the asbestos cancer theory
is based are not supported by chemical or biological experimentation
The authors said
But at no stage in all these impressive researches was any
clue obtained which might have offered any support to the possibility
that asbestos could act as a carcinogen There is no reliable criterion
by which one can anticipate carcinogenicity and as is well known relatively
carcinogen sufficient minute changes in the structure of a chemical to diminish or eliminate carcinogenic action
are
T T .
regarded carcinogen If asbestos is indeed to be
as a
some - need is felt to demonstrate
property which can be
regarded something more than inertness
the
as
eo
:
as, ann:
i
ee
vee
eo eee
At the 1965 Symposium Schepers ( ) reported the results of
animal experimentation His work shows that chrysotile asbestos is neither
carcinogenic of itself in rats nor does it promote the effect of a known
carcinogen beryllium when that substance is administered with asbestos
Said Schepers .
emn
Le
21
. a
ee
In a study completed a few years ago at Saranac Lake we
. proceeded as follows We used laboratory bred albino rats which in
previous experiments with beryllium sulfate beryllium oxide and beryllium
fluoride had yielded abundant pulmonary carcinomata See Progress in Tumor Research Karger Basle 1962 Two groups of rats were started
respectively on exposures to chrysotile dust and beryllium sulfate dust
A third group served as en undosed control After six months of
exposure the beryllium group was split into two halves One group continued . in the beryllium environment Another group was now exposed to chrysotile
dust for six months The original chrysotile group was dealt with in
half identical manner i.e. one
was continued on chrysotile and the other
' half transferred to beryllium exposure All exposures were terminated
after a year The prevalence of pulmonary neoplasia was statistically . contrasted for each group In essence the following was found
Group 1. ' Group 2
Group 3
.
Group 4
Group 5.
Undosed controls No neoplasia
Chrysotile exposure only No neoplasia
Beryllium exposure only About 1/4 of the
animals developed pulmonary neoplasia
Beryllium followed by chrysotile developed pulmonary neoplasia
About 1/5
Chrysotile followed by beryllium About
1/10 developed pulmonary neoplasia
;
-
neny
e
yet
tle
eb
fe
7
One may infer the following from this experiment
tte
ee
ee
__.
a The animal species is normally not pulmonary carcinoma prone but possesses a latent potential toward neoplasia when adequately challenged
b. Beryllium sulfate is a potent carcinogen when inhaled for six or more months at a daily aerosol concentration of 12 gamma per
cubic foot of air
c Chrysotile evinced no carcinogenic potential in this animal species
d Chrysotile did not act as a carcinogen with beryllium
sulfate
e The lower incidence of neoplasmata in Groups 4 and 5 does not necessarily imply that chrysotile acts as an carcinogen but may perhaps be explained by the lesser exposure period to the beryllium and the shorter available induction time for pulmonary
carcinogenesis oe
Dr. Schepers had previously commented sceptically on the
ee
em
reports of asbestos bodies found in the lungs of persons with no
history of exposure , and had discounted the theory that automobile
quantities brakes might release harmful
of asbestos dust into the air
me
\
tans
amt
we
Dr. Kenneth W. Smith ( ) Medical Director Manville Corporation , presented the results of tests which disprove this theory
ra
In our Research Center we are continually testing our brake linings and
those of other companies on various types of automobiles and trucks When .
we first heard of the supposed association of the disintegration of the
brake lining with the asbestos bodies in lung juice we immediately started
a program of pulling the wheels off these test automobiles and examining
the brake lining dust Various samples were examined after 5,000 miles
of driving 10,000 15,000 miles etc. There was ample dust for examina
tion but in not one of these samples of our own manufacture or samples
of brake lining made by other manufacturers in this country could we identify a chrysotile fiber As far as we are concerned it is impossible for
any of our type brake lining manufactured in this country to disintegrate
and liberate chrysotile asbestos fibers which can be inhaled to form as-
bestos bodies This is quite understandable because chrysotile asbestos
fiber disintegrates when exposed to the tremendous heat created by the .
material friction of the brake drum on the brake lining
nee
ee
-.
et
1.
@
@.
we
.
oe
incidence u of the high addition t manufactu
I would in that Ne believe th
using using onl
of other It app
the use
conferen Frank
by John
| look He
mae e
-23-
VII Summary The theory that lung cancer is caused by exposure to asbestos
has been proven and should be regarded with scepticism at the present
time The following facts tend to cast doubt on the theory
1 Asbestos is not one substance but many substances , differing
in chemical and physical composition
2. A recognized disease of the lungs , asbestosis is
progressive and has no clear dose relationship .
animals 3. It is
laboratory
certain
induced in
No !
; a whether asbestosis can b7e
!
oo
4 Asbestosis is difficult to diagnose and is frequently confused -
|
with other diseases caused by dust inhalation
Fill
asbestos Exposure =
produced cancer in We&
6. It is not certain that called asbestos bodies sometimes
. found in lung cancer victims are actually asbestos many other substances
cause similar lesions
7. In the United States and Canada the occupational groups
most heavily exposed to asbestos dust miners and fabricating plant workers ,
have no significantly different rate of lung cancer than is found in the
|
general population
8. The called asbestos workers in the insulating and building
trades work with a variety of different materials , which may or may not
include asbestos
the most
In any case they are exposed to various types of dust
their exposure to asbestos dust is certainly moderate compared to
the exposure of miners or asbestos fabricating plant employees
-24-
9. Only a very small part of the population is occupationally | _ exposed to asbestos There can be no possible correlation between this
exposure and the reported increase in lung cancer cases in recent years
ate.
e .
mee oe
cen
woman
December 9 1968
REPORT OF MEETING
December 3 1968
Public Relations Committee Environmental Health Task Force
ae
a
F. J. Solon Jr. - Chairman W. P. Raines
M. M. Swetonic
Bert Carl
Goss - Hill & Knowlton
Thompson - Hill & Knowlton
NewslettFeorr Mount Sinai Project
It was agreed that the money for producing the newsletter ought to come out of the basic research program budget The mechanics of writing approving printing and distributing the newsletter were discussed Hill and Knowlton agreed to prepare an outline of these mechanics - including costs --~ that could be used as a sort of check list for a meeting with Jobe and Dr. Selikoff to iron out any difficulties Matt Swetonic was assigned the task of checking with Hibbert Printing Company to see whether final printing and mailing stages of the program could be handled through the M Advertising & Public Relations production depart-
ment's art costs
Business Week Article
Med. Various avenues of approach to Business Week for the plNaacement
of a favorable story on the Mt. Sinal
program were discussed The decision was made to approach the Labor Editor rather than go higher in the organization Carl Thompson of H & K outlined the specific approach and pointed out the pros and cons in the
move
It was decided that any attempt to place a favorable article in Contractor News should be delayed until after the Business Week approach is concluded since the latter is the big circulation
book and we should go at it first
San Francisco Department of Public Works Discussed the letter received by Dr. Selikoff from the San Francisco Department of Public Works requesting information on the potential dangers of asbestos to the general public Needs further investigation Solon will talk with Burt Jobe
Jack Solon recommended strongly it was agreed to by all members of
the committee that M set up a team of M people knowledgable
in the field of asbestos and health who would be ready at a moment's notice to fly to trouble spots like San Francisco and move in on the situations
-3-
O'Toole and The Washington Post
62 62 62 62
Tom O'Toole of the Washington Post contacted Dr. Selikoff about
a series of articles examining a wide range of environmental
health problems including possible health dangers associated with asbestos beryllium coal dust radiation It is believed
the series is designed as a boost for the Health & Safety Bill in
the next Congress O'Toole interviewed Selikoff on December 2
an article appeared in the Washington Fost December 4 - a
damaging article basically concerned with dockyard workers
Ralph Nader
Nader has occasionally mentioned asbestos in his listing of potentially harmful dusts Should he at some time in the future decide to crusade against asbestos it was decided that more could be gained from sitting down and talking with the man than by taking the General Motors route H & K sources indicate that
Nader is a reasonable man and can be approached on that basis
It was agreed however that he should not be contacted unless
he takes on Manville first
Manville Situation Addendum to November 6 minutes Dr. Merrill recently remembered that Dr. Demy of Somerset Hospital did indeed approach him in 1966 for work history records and that
he did not follow through by providing them This is of course
in direct contrast to the statement that we made to the Messenger-
Gazette last month This once again points out the need for batter
-4-
contacts between M medical representatives and the outside
scientific community especially in the Manville area