asbestos

and your health

In over twenty years of operations at Cas-
siar mine there has not been one reported
case of asbestos-related disease.

But this is not the whole story. There is
much more that you should know about
asbestos and your health.

First you should know that Cassiar does
not know everything about asbestos and
health. Nobody does. However, we can
say that extensive medical and technical
research related to asbestos and health is
going on in laboratories all over the world.
The results of this research have provided
us with knowledge that was unknown in
the mid-sixties. The knowledge gained is
now being put to work within the working
environment at Cassiar, and this will con-
tinue as new information becomes
available.

You should also know that in some quar-
ters asbestos has been labeled a ‘danger-
ous’ substance that can be injurious to
health. Under certain circumstances
this may be so — in much the same man-
ner as the excessive consumption of alco-
hol can be detrimental to health. Even the
use of health-restoring medicine can be
labeled ‘dangerous’ if used contrary to the
doctor’s instructions. But despite these
‘dangers’ we continue to enjoy a convivial
cup, and take our medicine as ordered by
the doctor. In short, neither of these two
examples will do us the least bit of harm if
they are properly handled.

Our job then, at Cassiar, is to mine and
mill asbestos — and handle it properly.
Maintaining this goal will keep the ‘dan-
gers’ within acceptable bounds, thus reduc-
ing health hazards to a minimum.

This raises the question: What is dangerous
about asbestos?

First of all asbestos is not a poison like
arsenic — nor is it dangerous to touch.
However, in recent years research has es-
tablished that there are health hazards
broadly associated with the ‘breathing in’

20

of large quantities of fibre over a long
period of time — some say 15 to 20 years
or more. No one can say for sure. The im-
portant point is that this condition can only
exist if there is no dust control.

At our Cassiar mine most of our dust pro-
ducing areas are being brought under con-
trol. Areas that are not under control are
being identified and worked on. However,
in spite of dust control measures there are
still some areas where the wearing of a
mask is required. These areas are under
active study and dust control programs are
underway.

In the mill a Wheelabrator dust collecting
system filters the air for recirculation. This
helps maintain a comfortable temperature
during severe winter weather and assists in
the control of dust.

You should know that air at the mine and
in the mill is frequently tested on a continu-
ing basis for the presence of fine ‘floating’
fibres. This test consists of pulling a meas-
ured quantity of air through a ‘membrane
filter’ which removes all of the dust and
fibre. The membrane filter is then ex-
amined under a microscope and the
number of fibres trapped on the filter are
counted. The results are reported as the
number of fibres in a cubic centimeter of
air (about the size of a thimble).

Occupational exposure testing methods are
not the same throughout the world. Some
countries use one method and others use
another. The method used at Cassiar is re-
garded as the latest technique for monitor-
ing occupation exposure. As new know-
ledge is gained, and new ideas introduced,
we can expect changes and improvements
in both standards and testing methods.
You will be kept advised of any changes or
improvements as they occur.

A slightly different type of test is performed
to check Cassiar’s community air. A large
volume of air is drawn through a glass
fibre filter for a period of twenty-four
hours. The amount of airborne dust col-

lected on the filter is weighed and a result
obtained in millionths of a gram per cubic
meter of air (a cubic meter tank would
hold about 220 gallons of water). In addi-
tion, the air is tested for the total amount
of pollutants falling onto the Cassiar sur-
roundings. This is measured by means of
an open-top gauge exposed to the outside
air. All test levels in the Cassiar townsite
fall within the standards set by law.

Health problems are not unique to the as-
bestos industry. Many substances and mat-
erials in common use today can be detri-
mental to health if conditions are not
controlled. In fact environmental control
is the key to a high standard of industrial
health. This is clearly indicated by the ex-
periences of a British asbestos textile fac-
tory. In the early thirties the factory found
signs of asbestosis in some 80 percent of
its employees with twenty or more years of
exposure. In 1957 another survey was
taken at the same factory. It showed that
after the installation of dust control, the in-
cidence of asbestosis had dropped to 3
percent among workers with twenty years
or more exposure. Lung cancer, under pre
1933 conditions, was ten times that of the
general population. Today, at the same
factory, lung cancer is 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.

Basically, the known facts about asbestos-
related disease in which you will be in-
terested are: |

First, the effects of excessive inhalation of
asbestos are related to time and dose. This
means that disease may develop, gener-
ally, only after the heavy inhalation of as-
bestos over a long period of time. Thus,
with proper control, levels of exposure can
be reduced to the point where exposure to
asbestos will not result in any significant in-
creased risk of disease.

Second, there is presently no real evi-