ASBESTOS and HEALTH

I recently received a letter 6 an associate of
_mine that prompted me to speak to you this morning on the
very important and currently topical subject of "Asbestos
and Health". Let me read his short letter - you may well
- have the same thoughts in mind:

"Dear Mr. Christian:

I have been pondering over this question of the

‘health hazards of asbestos and putting myself in the pos-_

ition of ‘an asbestos worker or a citizen living in an
asbestos-dominated community. Here are some questions
that I might be prone to ask. I'm bringing these quest- —
ions up as I think that the material that has been put
forth both by the press and by the industry is so highly
technical that the true meaning or significance of these
reports is being lost’ on the man in the street and instead
he is being fired with anxiety by the sensationalism of
jargons that are over his head.
: What is asbestos? What kinds are there? What are
the differences between the different types of fibre?
Where do these fibres come from?

It has been made to sound like a poison similar to

arsenic. Why is it so dangerous? What makes it so dan-
gerous? What is happening in the body when excessive
amounts of asbestos are taken in? . What is happening to

me when
stomach
touch?
What is
We:

I have asbestos particles
or in my digestive tract? Is it dangerous to
Can it do me harm just be handling the material?
the meaning of five fibres per c.c.?
have trouble as lay people visualizing any fibre
smaller than a human hair, so when I think of five fibres
I think of five short pieces of hair inside a thimble.
If I was to inhale 5,000,000 c.c. of air per day, then I
must be consuming 25,000,000 fibre particles per day.

What is the weight to 25,000,000 fibres? What
percentage is being daechareed by my body and what percen-
tage is being retained? If I am unfortunately going to
contract asbestosis, is there any cure for this? What is
happening to me with asbestosis? |

I happen to live in Toronto. What is my mortality
rate living in this city as compared to Thetford or Sud-
bury or for that matter Regina? I would pose the same
questions with respect to particles of fibre contained in
volumes of water as I did above with respect to air.

Over a lifetime, what kind of weight of fibre are we

actually talking about? Is it visible to the naked eye,

- even over a lifetime? Life is finite, but I don't want
to die prematurely. What assurance can you offer me as
a potential employee in your operation that I am not
going to unnecessarily shorten my life?

in my lungs or in my

Yours sincerely,"

This is a very sincere letter from a deeply concern-
ed person. I have replied*to the best of my ability and
would like to read what I said.

Dear Mr. X:

Thank you for your very thoughtful letter. You will
appreciate that I am not a medical doctor, nor a scientist
and that the opinions and facts, that I can give you in
reply to your questions, have been gleaned from studying
published reports from the medical and scientific world.
As you have expressed confusion over the use of highly
technical terms and numbers, I will attempt to express
myself in everyday language, even though it may be at
the expense of absolute accuracy.

"WHAT IS ASBESTOS?"

The term "asbestos" applies to all minerals which
have one common attribute, namely, the ability to be
separated from the parent rock in the form of a fibre.
Chrysotile asbestos is the fibrous form of serpentine
rock and represents 95% of the world's commerctal fibre
production. Crocidilite and Amosite are the most im-
portant fibrous forms of another rock known as amphibole.
These types of asbestos have slightly different chemical
and physical properties than-Chrysotile and hence differ-
ent practical uses. When we speak of "asbestos", we are,
therefore, really talking about the fibrous forms of rocks
which are quite common throughout the world. The com-
mercial asbestiform amphiboles are largely found and
mined in South Africa and Brazil, whereas the Chrysotile
variety of serpentine is more widespread and is found in
most countries of the world. The fact that asbestos
fibres are very strong (similar to high tensile steel),
and can be broken: down to extremely fine dimensions
(1,000th the diameter of a human hair), makes it a very

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_ and I mean 15-20 years or more.

useful material for reinforcing, cement, plastics and
rubber, or it can be spun or woven into yarn or cloth
for clutch facings, brake linings and protective clothing.

"WHY IS IT SO DANGEROUS?"

First of all, let me say that it is not a poison like
arsenic, as you suggested, nor is it dangerous to touch.
The health hazards that, in recent years, have been found
to exist are broadly associated with the inhalation of
large quantities of fibre over prolonged periods of time,
During processing some
of the fibres become very fine, and without proper dust
control will readily float in the air. Naturally, some
of these will be inhaled, but a high percentage will be
rapidly removed from the respiratory tract by ciliary
action.

"WHAT ARE THE ASBESTOS DISEASES ?"'
There are now three recognized diseases:

(1) Asbestosis - This is one variety of the lung
disease called "pneumoconiosis". It is a progressive
fibrosis of the lung, which can’ make breathing difficult
and can lead to other disabilities. Occurrences have beer
clearly related to prolonged inhalation of respirable
sized fibres over a period of many years. Those cases of

‘asbestosis whieh are appearing today are the result of

exposure to heavy concentrations of asbestos dust pre-

valent many years ago, when little was known about the

risks involved. It has been shown that, when the level
of exposure is reduced, the auci dente: of asbestosis is

also reduced.

(2) Bronchogenic Cancer - There is now medical evid-
ence to indicate that asbestos exposure is associated
with an increased frequency of bronchogenic cancer in
workers who have first developed asbestosis. At the pre-
sent time, we do not know what causes the cancer, whether
it is the chemistry of the asbestos, the fibrous nature
of the material, or something else quite unrelated. As
you are aware, there are many other known carcinogens,
which include coal tar, benzidine, tobacco, vinyl chloride
X-rays and even Baten tac, These, along with asbestos are
currently the subject of a great deal of research. You
will also be interested to know that few, if any, asbes-
tos related lung cancers have been found in workers who
are non-cigarette smokers and do not have asbestosis.
This fact has been well documented by a number of resear-
chers.,

(3) Mesothelioma - Mesothelioma is one of those rare

-and newly recognized cancer diseases and is a malignant
. tumor of the lining membrane of the chest and abdominal

cavity. By no means are all such tumors associated WEph
asbestos, but where a relationship can be established,
the exposure has largely been Crocidilite (blue asbestos) .
Far fewer cases have been found where the exposure was
limited to Chrysotile fibre, which is the type mined in
Canada. An investigation of the 236 known cases of
mesothelioma tn Canada between 1960 and 1970 showed that
only nine were associated in any way with the Quebec
Chrysotile mining and milling industry. Seven men had
been employed and two were women whose fathers worked in
the industry.

THE MCDONALD REPORT ON THE ASBESTOS MINES AND MILLS OF
—<—$—$—$<—<——————— i eee eke Sen ANY MibLbe OF

QUEBEC.

A group of very capable Canadian doctors and scien-
tists have since 1966 been studying the history of 11,572
persons born between 1891 and 1920, who were, or are
still employed in the Quebec zahestes mining industry.
They Have found that the industry has a lower mortality
rate for people of comparable age than the general popula-
tion of Quebec. Hence, within the industry group. those
who had a long history of exposure to the two highest
dust classifications showed a higher death rate from res-
piratory cancer and pneumoconiosis than the others. The
studies are continuing and the report encouragingly sug-
gests that a one percent risk of acquiring a clinically
significant disease over a working life of fifty years in
an asbestos mine can be achieved by maintaining threshold
levels of 2-4 million particles per cubic foot.

Possibly, I should at this point tell you about the
two methods of measuring the dust. The impinger method
sucks in a given amount of air and the fibre and dust
particles present impinge on a treated glass slide. They
are counted under a microscope and are reported as mil-
lions of particles per cubic foot’ of air. The newer