Page 5 - Asbestos Training

Chapter 2 - Health Effects Associated with Asbestos Exposure

The adverse health effects associated with asbestos exposure have been extensively studied for
many years. Results of these studies and epidemiological investigations have demonstrated that
inhalation of asbestos fibers may lead to increased risk of developing one or more diseases.
Exactly why some people develop these diseases, and others do not, remains a mystery.

It is important to recognize that most people who have died as a result of asbestos exposure were
workers who were frequently exposed to high concentrations of asbestos fibers each working day
with little or no protection.

The Respiratory System

Since the primary health effects due to asbestos exposure act on
the lung, it is necessary to gain a basic understanding of the
respiratory system. Air inhaled into the body passes through the
mouth and nose into the windpipe or trachea.
The trachea splits into two smaller airways called the bronchi. Each
bronchus divides into smaller and smaller tubes that terminate into
air sacs called alveoli. It is in these air sacs that oxygen is
absorbed into small blood vessels; waste gases, such as carbon
dioxide, pass out of the blood.

The lung itself is divided into two halves and sits in the pleural
cavity. This cavity and the outside of the lung itself have a membrane lining that is referred to as
pleura. These linings are in contact with each other and are very moist. Just like two panes of
glass with a drop of water between them, these linings slide easily across each other, but are
difficult to pull apart. Accordingly, as the chest cavity expands, the lungs expand and air rushes
in. If these linings were to become damaged, inhalation could not occur properly.

Filters

The body has several mechanisms by which it "filters" the air it breathes. First, very large particles
are removed by the nose and mouth. Many smaller particles impact the mucous-coated walls of
the airways and are caught. These airways have a hair-like lining (ciliated cells) which constantly
beat upward. Accordingly, particles caught in the mucous are swept up into the back of the mouth.
From here particles are swallowed or expelled.

Cigarette Smoking

Cigarette smoking temporarily paralyzes these ciliated cells inhibiting the body's natural defenses
against the unwanted dust. During the night, in the absence of smoke, the hair-like cells start
working again and carry large amounts of mucous into the back of the mouth. This causes the
so-called "smoker's hack" in the morning. After the first cigarette or two, the cleansing mechanism
is paralyzed again and the coughing stops. It should now be evident why cigarette smokers who
are exposed to asbestos appear to be at greater risk.

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