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Asbestos
How Asbestos Works
BY TIFFANY CONNORS
If
asbestos is such a danger, and we've been removing it since the 1980's,
shouldn't it all be gone by now?
You
would think so, but even though it seems like we've had a lot of time to get it
out of our homes, schools and workplaces, asbestos has been around for 3,000
years, so it's had a head start.
Getting
rid of asbestos isn't as easy as changing your clothes. Besides, it's not such
a villain as long as it isn't disturbed.
Asbestos hasn't
been produced in the United States since 2002.
However,
the United States still imports approximately 3,000 tons per year, and there
are plenty of older buildings where asbestos still resides [source: Asbestos Project Plan].
Why?
Because removing it can be more dangerous than leaving the original substance
intact; if it's properly sealed and left undisturbed, asbestos doesn't pose a
danger to us.
Asbestos
is in fact a naturally occurring substance, so we're all exposed to some
degree. The difference between most people and the danger zone is the amount of
exposure.
With asbestos, the
problem comes when we inhale the fibers.
And
while we exhale a lot of them right back out of our system, some of the fibers
can stick around and scratch our lungs, causing scarring and inflammation that
can lead to a variety of serious respiratory diseases.
These
fibers, which are used in construction materials because of their durability,
build up over time and are strong enough to stay in our lungs forever.
So
even though we may feel fine now, the same fibers we breathe in today could
give us cancer 30 years from now.
But what exactly is
asbestos? And how can we protect ourselves and our loved ones from its dangers?
In this article, we'll explore asbestos and what you need to know.
What Does Asbestos Look Like?
In most commercial forms, asbestos looks like attic insulation -- a
ball of thick fuzz. The individual asbestos fibers that are released into the
air are microscopic.
The U.S.
government defines asbestos as a naturally occurring group of fibrous minerals
that are very strong, can be woven, and resist heat and most chemicals [source: EPA].
The current
federal definition includes these classes of asbestos:
· Chrystotile
· Amphibole
(with subsets:crocidolite, amosite, anthophyllite, tremolite and actinolite)
While both
chrystotile and amphibole are known to cause respiratory diseases, the more
durable, thinner strands of amphibole asbestos are considered more dangerous
and more likely to cause mesothelioma (a form of cancer caused
by asbestos) because they tend to stay in the lungs longer [source: Agency for Toxic Substances and Disease Registry].
However, the
more flexible chrystotile asbestos is used in about 95 percent of all asbestos
in commercial products and is still considered carcinogenic [source: Encyclopedia Britannica].
Asbestos has
been used for thousands of years, dating as far back as the ancient Greeks.
Its
durability and ability to withstand heat and erosion made it attractive to
builders, and it was even used in some clothing because of its fire -resistant
qualities. Modern asbestos production began in 1868 through mining deposits [source: Encyclopedia Britannica].
Reports of
long-term harmful effects of asbestos exposure began appearing in the 1970s,
although dangers associated with asbestos were suspected decades earlier.
In 1989, the
U.S. government issued a ban on products containing asbestos. This regulation
was overturned in 1991, but certain products were still banned, as were
"new uses" of asbestos [source: EPA].
Where is Asbestos?
The fact is, we're all exposed to asbestos,
although usually in such small quantities that it poses no threat.
The
typical air concentration of asbestos fibers is 0.00001 to 0.0001 fibers per
milliliter.
In
comparison, U.S. workplaces are limited to exposing employees to 0.1 fiber/mL,
and significant exposure is considered years of exposure to 0.125 to 30
fibers/mL [source: Agency for Toxic Substances and Disease Registry].
In nature, the
fibrous asbestos is embedded in rocks, most commonly ultramafic rock (a type of
igneous rock), which is found in much of California and near fault
zones. Not all ultramafic rock contains asbestos, but all ultramafic rock has
the potential to contain veins of asbestos [source: Agency for Toxic Substances and Disease Registry].
Mining
areas in the eastern United States have also been discovered to contain
naturally occurring asbestos.
To
obtain the asbestos for use -- and to make it airborne -- the rock must be
crushed to release the fibers.
In commercial
products, asbestos is still found in heat and acoustic insulation, fire proofing,
and building materials like roofing and flooring.
Additionally,
asbestos can be found in older automotive parts like disc brake pads
and drum brake linings, which used asbestos because of its friction
properties [source: Asbestos Project Plan].
Banned
new products include flooring felt, cement shingles (also known as asbestos
siding), and corrugated, commercial and specialty paper. However, older
material that used asbestos can still be found widely [source: EPA].
Asbestos testing
should be conducted by licensed government agencies, and trained asbestos
abatement professionals should be the only ones performing the removal.
In
some cases, it's safer to seal the asbestos in rather than remove it.
For
more information on getting asbestos out of your house, see Is it safer to
remove asbestos from a building or leave it there?
In
cases of emergency asbestos exposure – when Hurricane Katrina hit New
Orleans or the fall of the World Trade Center, for example -- the best thing to
do is get out of the area (keeping your mouth and nose covered with a wet cloth
when possible) and contact your state and local agencies or the Environmental
Protection Agency for more information on proper testing, removal or
containment.
Now that you know
what and where to look for asbestos, we'll talk about warning signs to watch
out for if you've been exposed to asbestos.
WHAT
IF I FIND NATURALLY OCCURRING ASBESTOS?
Natural
weathering or human disturbance can break down naturally occurring asbestos
into fibers that can be inhaled and cause respiratory diseases.
If you live in an area where naturally
occurring asbestos has been disturbed, avoid unpaved surfaces, and wet any dirt
before digging [source: Agency for Toxic Substances and Disease Registry].
By covering naturally occurring asbestos
with clean soil or planting grass, you can reduce your exposure. And be sure to
contact your local government for safe removal [source: EPA].
Diseases and Symptoms Associated with
Asbestos Exposure
So you've been exposed to asbestos; how likely are you to get sick?
Diseases from asbestos exposure take a long time to appear.
The typical
range is 10 to 40 years after exposure, although it depends on the type of
illness as well as other factors, such as whether the patient is a smoker (which
increases the probability of the person developing respiratory ailments).
The
concentration, duration and frequency of asbestos exposure also has a hand in
determining your chances of developing an illness.
The long and
thin fibers of amphibole asbestos are more likely to reach the lower airways
and inflame the lungs and pleura,
the membrane that lines the lungs [source: Agency for Toxic Substances and Disease Registry].
The three
most common illnesses associated with asbestos exposure are lung cancer. Asbestosis
and mesothelioma. All three share the common symptom of difficulty breathing.
Lung cancer
causes the most deaths due to asbestos exposure, although asbestos exposure is
not the only culprit [source: EPA].
Common symptoms
include coughing, chest pains, hoarseness and anemia.
Asbestosis
is the result of asbestos scratching and scarring lung tissue. It usually shows
up the earliest of all the respiratory ailments -- typically 10 to 20 years
following exposure [source: Agency for Toxic Substances and Disease Registry].
A common
symptom is a dry, cracking sound in the lungs while inhaling.
Mesothelioma
is a rare cancer that affects the pleura. The majority of mesothelioma cases
are due to asbestos exposure [source: Mesothelioma].
It may take
years to develop, and may resemble pneumonia. Some common symptoms include
chest pains and a persistent cough.
If you think
you may have an asbestos-related respiratory illness, consult a pulmonary
physician immediately.
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