What is Asbestos?
Asbestos
is a common name for a group of naturally occurring fibrous silicate
minerals that are made up of thin but strong durable fibers. These
fibers generally vary in size and physical shape.
Because
of its physical properties, asbestos was used extensively in
construction and many other industries. For example, asbestos would commonly be found in a variety of man-made products including insulation,
ceiling and floor tiles, roof shingles, cement, automotive brakes and
clutches. |
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Asbestos
containing material that can be crushed into a powder is termed
“friable asbestos.” When asbestos containing materials become friable,
there is chance that asbestos fibers can become suspended in air. It is
under these conditions that airborne asbestos fibers represent the most
significant risk to human health.
Asbestos
is a potential health concern because long term, chronic inhalation
exposure to high levels of asbestos can cause lung diseases such as
asbestosis, mesothelioma, and/or lung cancer.
Asbestosis is a scarring of the lungs due to lodging of asbestos
particles in the small air pathways of the lungs. Blood flow to the
lungs may also be decreased and this may cause enlargement of the
heart.
It
is important to note that information on health effects related to
asbestos exposure most commonly come from studies of people who have
had long term exposures to relatively high levels of asbestos in the
workplace.
You
are most likely to be exposed to asbestos by inhaling asbestos fibers
which have become suspended in air. Very low levels of asbestos are not
likely to be harmful to your health, and low levels can be detected in
almost any air sample. These are generally called “background” levels..
To
put asbestos risk in perspective, here is a story of a most hazardous
asbestos mining operation in Australia, going back to the 1950s:
Working
conditions during the operation of the mines and mill at Wittenoom were
extremely poor. Employees worked continuously amongst the asbestos dust
in the poorly ventilated mine and mill, usually without effective
personal protective breathing equipment.
Asbestos Bagging Area
It
was generally dirty and dusty; there were clumps of asbestos all over
the floor and one's clothing was rapidly soiled by contact with any
surface. Every operation in the mine was associated with dust.
At
the bagging plant the floor and the men who stood over the open bags,
which were filled from a chute, were covered in clumps of asbestos. In
the mill, all tasks were associated with dust.
Workers Bagging Milled Asbestos at the Old Bagging Plant
The
dust extraction system removed some of the dust and discharged it above
roof level, but it flowed back to the mill and staff offices. The dust
was also discharged at the same level as the main entrance to the
underground mine, so the air entering the mine already contained dust.
Airborne Asbestos Dust Visible Outside the Mill
The
waste material, tailings and remains from the dust extraction system
were dumped from hoppers into open trucks and driven further up the
gorge, over unsealed roadways and raising clouds of dust. Airline
pilots claim they could see the blue haze on the horizon considerable
distances away from Wittenoom.
One
worker recalled the one hundred-watt light bulbs hanging from the
ceiling of the shed looked like candles. You couldn't recognise a man
until you were within a couple of feet of him, because the faces of the
workers were coated in dust, like pancake make-up.
Parts
of the material in in this issue have been extracted from a
July 2003 Fact Sheet by Cal EPA Department of Toxic Substances Control.
You can find past issues of our "Environmental Enlightenment" at www.amiadini.com:
Wealth of information about environmental site assessments in the real
estate transactions and issues concerning assessment and cleanup of
contamination in the subsurface soil and groundwater. |
