‘method is the membrane filter. A measured quantity of
air is pulled through a membrane filter which removes all
the dust and fibre. In this method only the fibres are
counted and hence it is difficult to relate the two res-
ults. This latter test is reported as the number of fib-
res in a cubic centimeter of air. Both are highly sus-
ceptible to human error. Your thimble is 4 good estimate
of a cubic centimeter, but it would take 2,000 fibres
placed end to end to span the width of the thimble, and
the thickness of the fibres would be many times less than
‘he human hair you envisage.
The McDonald Report confirms the results of other

studies in the Soviet Union and Italy which indicate that \)

the risks are much lower in the Chrysotile mining and
milling industry than reported from the New York insul-
ation workers or the British Naval Dockyards.

At our Cassiar mines most of the emissions to the
atmosphere are now under control, or in the process of
becoming so.
control measures, there are still some areas where the
wearing of masks is required. These troublesome areas

are under active study and an extensive program, designed \)

to achieve the best possible threshold levels, is being
undertaken. The most serious obstacle in our path is the
shortage of personnel. You are already aware of some of
the serious effects this has had on production over the
past several years. Incidentally, in twenty years of
operation we have not had one reported case of any of

the three asbestos-related diseases, but we must not be
complacent in view of the long latent period (30-45 years
which can elapse between the first exposure and the dev-
elopment of mesothelioma. This, along with the Quebec
studies, is the best assurance we can give any potential
employee that things now appear to be under control and
the risk of premature death or impairment of health is
very remote indeed.

"IS THERE A HAZARD IN THE CONSUMER INDUSTRIES?"

° Asbestos from our Cassiar and Clinton mines is used
for the greatest part in the asbestos-cement industry,
followed by the asbestos textile industry, and to a much

. lesser degree in the manufacture of filters, compressed
sheet packing, reinforced plastics, and so on. Of these,
the textile industry, which until recently was exclusive-
ly a dry carding, spinning and weaving process, had had .
some comparatively serious dust problems. In the early
1930's, in a particular textile factory in the United
Kingdom, signs of asbestosis were found in some 80% of
the workers with twenty or more years' exposure. Another
survey in 1957 of the same plant showed that in workers

_ with twenty years' exposure, after the installation of
dust control, the incidence of asbestosis had dropped to
3%. The lung cancer rate in workers in the plant exposed
to pre 1933 conditions was at ten times that of the

general | populations, whereas it is currently reported to
be at: the same level as the general population. .This
example clearly demonstrates that with experience and
improved technology asbestos can be handled safely.

"IS THERE A HAZARD TO THE GENERAL PUBLIC?"

You have asked about the risk of living in Toronto,
as compared to Thetford or Regina. Most of the studies
on the relationship of asbestos diseases to mortality e
rates have been carried out in the occupational field,
and before absolutely denying any public health risk,
scientists agree that more data must be collected over an
extended period of time. However, a number of studies
have already been carried out and there is to date no
evidence, scientific or otherwise, to suggest that anyone
in the general public has ever contacted any disease from
exposure to the minute amounts of asbestos released into
the community air through the use, or wearing, or weather
ing of finished asbestos products.

As far as water is concerned, the Conference of the
International Agency for Research on Cancer, held in
Lyon, France, in the fall of 1972 - which I feel should
represent as qualified and authoritative an opinion as
is available - provided the following information: -

°

’ Question:

"Is there evidence of an increased risk of
cancer resulting from asbestos fibres present
in water, beverages, food, or in fluids used
for the administration of drugs?"

Answer: "Such evidence, as there is, does not indicate

any risk."

3 You might well ask at this point, "If this is so,
then why the great hue and cry?" In the scientific,
legal and bureaucratic world, there are those who have a
craving to push the panic button and who define "a Haz-
ard" as "something which may possibly occur", even though
they are unable to produce any evidence to support their.

Inside the bud tadake: in spite of extensive \)

be replaced by other types of materials.

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Page 5

contentions. No one denies that there have been - and
still are - problem areas. The world today is faced with
many, many problems, all of which must be viewed in their

_ proper perspective, and "panic" reporting and "panic"

legislation is not the answer. The asbestos and other

industries are working hard to correct the conditions

which are thought to create a health hazard. Unfortunat-
ely, final proof will not be available for twenty, thirty
or even forty years. In the meantime, the best that any.
prudent person can do is to continue to research all
aspects of the problem, to analyze the facts and trends ©
as they become known, and to set goals and standards
which will progressively reduce the element of risk and
hopefully will finally eliminate it entirely.

"WHAT IS THE ASBESTOS INDUSTRY DOING ABOUT IT?"

In addition to the continuous.development of tech-
niques and equipment to improve dust control, the Cana-
dian asbestos mining industry, through the Institute of
Occupational and Environmental Health in Montreal, the
Industrial Health Foundation in Pittsburgh, and selected
hospital and universities is sponsoring or co-operating
in major epidemeological and research projects, designed
to identify and eliminate asbestos-related health risks.
There is still a great deal of research to be done.
Active studies are also underway in other countries, such
as England, South Africa, Italy and Russia. There is
already strong evidence to suggest that the physical
aspects, (i.e., the length, diameter and stiffness) of a
fibre is the real source of trouble, and not its chemical
composition. If this proves to be the case, then certain ©
other fibrous material may also become suspect and the
work currently being done on asbestos may well prove to
have been a great step forward in our search for a
healthier environment.

GENERAL COMMENTS

I sincerely hope that what I have said so far has
answered most of your pertinent questions. Before clos-
ing, I would like to add a few comments si a general
nature,

It has frequently been cuagiaoed that asbestos should
This can and
has been done in some products, but in others such sub-
stitution has been either very expensive, much less
effective, or even impossible. To forgo the many bene-
fits of asbestos products, simply on the basis of a
suspicion of possible hazards, would be irrational and
unwarranted, particularly so when we are still uncertain
of the health hazards that might arise from many: ‘other
replacement materials.

Amongst insulation workers in the United States: and
the United Kingdom, particularly those who worked in the

dockyards during the war years, some very serious health

conditions have been found and ably researched and report
ed upon. It is a sad story, and the result of a.lack of
knowledge at the time and possibly the exigencies of the
war years. Very valuable lessons have been learned which
will be of great benefit in solving the problems of the
present and the future.

In the matter of publicizing and reporting, pias
iis no doubt that it is far more dramatic and eye-catch-
ing to use headlines such as "ASBESTOS KILLS", or for
example to report "TWO MILLION FIBRES PER LITRE OF WATER"
than to report the same thing as approximately 4/1,000ths
of a millionth part of a gram. Let me put these figures
to you in another way. If 5,000 people agreed to drink

' two quarts of water, containing four million fibres per

quart, every day for 80 years, then they - the 5,000
people - would have swallowed in total one gram of
asbestos, which is a cubic pile a little more than half

- an inch on each side.

Whenever I have the opportunity, I assure you that
I will urge all those who have the responsibility for
researching and reporting to the public, through what-
ever media it may be, to remain as factual and fair in
their research as possible and to avoid the ‘half truths'
Excellent progress is being made in Canada in improving
industrial health and safety, in controlling pollution,
and in protecting the environment. Regulatory bodies are
being established at various government levels and in co-
operation with industry itself to measure and control to
the best of our combined technical ability those condit-
ions likely to create a risk to the wellbeing of workmen
and the public. ~The use of any of these problem areas
to solicit public sympathy and support for individual
political or monetary gains should be looked upon with ©
scorn by all decent thinking people.

Thank you once again for your letter. I hope that
I have put things in a little better perspective for you.

Yours sincerely,
J.D. Christian