Asbestos by huanghengdong



Asbestos was named by the ancient Greeks, although the naming of minerals was not very
consistent at that time. In 13 century, when Marco Polo was traveling to China, he described
observing miraculous garments that were cleaned by being placed in fires. These garments were
likely make from asbestos.

Some archaeologists believe that ancients used asbestos to made of shrouds, wherein they burned
their kings’ bodies, in order to preserve only their ashes, and prevent them being mixed with
those of wood or other combustible materials commonly used in funeral pyres. Others
concerned that the ancients used asbestos to make perpetual wicks for sepulchral or other lamps.
In more recent centuries, asbestos was really used for this purpose. Although asbestos causes
skin to itch upon contact, ancient literature indicates that it was prescribed for diseases of the
skin, and particularly for the itch. It is possible that they used the term asbestos for alumen
plumosum, because the two terms have often been confused throughout history.

What is asbestos?

Asbestos is a naturally occurring silicate mineral with
long, thin, flexible, silky fibrous crystals, which can be
made into a wide variety of forms and even be added to
materials as diverse as cotton and cement, including six
minerals: chrysotile (white), amosite (brown), crocidolite
(blue), tremolite, anthophyllite and actinolite. It’s strong enough to resist high temperatures,
                    chemical attack and wear, and to insulate well against heat and electricity.

                    Asbestos can be toxic. Inhalation of asbestos fibres results in a variety of
                    neoplastic and non-neoplastic disease of respiratory tract including:
                    asbestosis, benign pleural disease, and Mesothelioma and lung cancer. So,
                    since the mid 1980s, the European Union and most developed countries have
Fibrous asbestos banned asbestos. Till January 1, 2005 the European Union has banned all types
of utilization of asbestos and extraction, manufacture and processing of its products.

Industry usage

Since late 1800s, asbestos has been mined and used commercially in North America and became
more widespread during the industrial revolution. It has been used in many industries since the
first commercial asbestos mine began in the Appalachian foothills of Quebec in 1879. For
example, the construction and building industries have used it for strengthening cement and
plastics for insulation, roofing, fireproofing, and sound absorption. It also has been used in the
shipbuilding industry to insulate boilers, hot water pipes, and steam pipes. The automotive
industry uses asbestos in vehicle brake shoes and clutch pads. Asbestos has also been used in
ceiling and floor tiles; paints coatings, and adhesives; and plastics. In addition, asbestos has been
found in vermiculite-containing garden products and some talc-containing crayons.1

Table 1 World asbestos production during the 20th century (metric tons)

Asbestos production          1900      1940       1960       1970         2000   Cumulative during

                                                                                   the 20th century
Former Soviet Union           NA 102000        598743    1065943     983200             67100000
Canada                      26436 313514      1014647    1507420     320000             60500000
South Africa                  158 24850        159540     287416      18782               9920000
Zimbabwe                      NA 50809         121529      79832     145000               8690000
China                         NA 20015          81647     172365     370000               7700000
Brazil                          --   500         3538      16329     170000               4540000
Italy                         NA    8271        59914     118536          --              3860000
United States                 956 18198         41026     113683       5260               3280000
World production            31587 573728      2213533    3493800    2070000            174000000

NA: data not available/--: zero2

During the first three quarters of the 20th century, asbestos was mainly produced and consumed
in the industrialised countries, the two main centres being Canada and the former Soviet Union
which accounted for over two-thirds of world asbestos production in the entire 20th century.


2 Robert Virta, Worldwide Asbestos Supply and Consumption Trends from1900 to 2000, US Geological

Canada was the leading world asbestos producer until 1975 and the second-largest producer of
asbestos (possibly the largest deposits including chrysotile, crocidolite, and amosite) .

Asbestos consumption was also concentrated in the industrialised countries. The downturn
reflected not economic or technical causalities, but mainly labour campaigning against the health
disaster of using asbestos. Perversely, the extent of the damage in industrialised countries is now
being measured only after consumption has been slashed or halted altogether. This is because of
the long latency for the development of asbestos-related cancers.

In the late 1970s, the U.S. Consumer Product Safety Commission (CPSC) banned the use of
asbestos in wallboard patching compounds and gas fireplaces because the asbestos fibres in these
products could be released into the environment during use. In 1989, the U.S. Environmental
Protection Agency (EPA) banned all new uses of asbestos and also established regulations that
require school systems to inspect buildings for the presence of damaged asbestos and to
eliminate or reduce asbestos exposure to occupants by removing the asbestos or encasing it.

Health hazarders of exposure to asbestos

People may be exposed to asbestos in their workplace, communities, and homes. If asbestos
products are disturbed, their tiny fibres have been released into the air. After they have been
breathed in, asbestos fibres may be trapped by mucus in the lungs and stay there for a long time.
Over time, these fibres can accumulate and cause scarring and inflammation, which can affect
breathing and lead to serious health problems.

Asbestos has been classified as a known human carcinogen and has been shown that increase the
risk of lung cancer and mesothelioma. Some studies also suggested an association between
asbestos exposure and gastrointestinal and colorectal cancers, as well as an elevated risk for
cancers of the throat, kidney, oesophagus, and gallbladder. However, the evidence is

Asbestos-related diseases

Asbestos exposure may also increase the risk of asbestosis (an inflammatory condition affecting
the lungs that can cause shortness of breath, coughing, and permanent lung damage) and other
non-malignant lung and pleural disorders, including pleural plaques (changes in the membranes
surrounding the lung), pleural thickening, and benign pleural effusions (abnormal collections of
fluid between the thin layers of tissue lining the lungs and the wall of the chest cavity). Although
pleural plaques are not precursors to lung cancer, evidence suggests that people with pleural
disease caused by exposure to asbestos may be at increased risk for lung cancer3.


3 Asbestos: Health Effects.

               This is a peripheral adenocarcinoma of the lung. Adenocarcinomas and large cell anaplastic
               carcinomas tend to occur more peripherally in lung.


                   The dense white encircling tumour mass is arising from the visceral pleura. These big bulky
Mesothelioma       tumours can fill the chest cavity. The risk factor for mesothelioma is     Adenocarcinoma
               asbestos exposure. However, mesothelioma is rare even in persons with asbestos exposure.4

               Risk of developing an asbestos-related disease

               Several factors can help to determine how asbestos exposure affects an individual, including:

               ●       Dose (how much asbestos an individual was exposed to)

               ●      Duration (how long an individual was exposed)

               ●      Size, shape, and chemical makeup of the asbestos fibres

               ●      Source of the exposure

               ●      Individual risk factors, such as smoking and pre-existing lung disease

               Although all forms of asbestos are considered hazardous, different types of asbestos fibres may
               be associated with different health risks. For example, the results of several studies suggest that
               amphibole forms asbestos may be more harmful than chrysotile, particularly for mesothelioma
               risk, because they tend to stay in the lungs for a longer period of time.5

               Does smoking affect risk?

               Many studies have shown that the combination of smoking and asbestos exposure is particularly
               hazardous. Smokers who are also exposed to asbestos have a risk of developing lung cancer that
               is greater than the individual risks from asbestos and smoking added together. There is evidence

               4 Pictures from Occupational Hygiene Notes

               5 What Is Asbestos?

that quitting smoking will reduce the risk of lung cancer among asbestos-exposed workers.
Smoking combined with asbestos exposure does not appear to increase the risk of mesothelioma
. However, people who were exposed to asbestos on the job at any time during their life or who
suspect they may have been exposed should not smoke.

Protection and treatment for asbestos exposure

The Occupational Safety and Health Administration (OSHA) established regulations dealing
with asbestos exposure on the job.


OSHA                             All forms                         0.1f/ml [F], A1

ACGIH                            All forms                         0.1f/ml [F], A1

Province of Quebec               Chrysotile                          1 f/ml [F], A1

                                 Amosite and Crocidolite           0.2 f/ml [F], A1

                                 Other forms                         1 f/ml [F], A1

Workers should use all protective equipment provided by their employers and follow
recommended workplace practices and safety procedures. For example, National Institute for
Occupational Safety and Health (NIOSH)-approved respirators that fit properly should be worn
by workers when required.

Treatments for asbestos vary depending on the type of disease the person contracts. There are
many options and some are disease-specific, which means that the treatment option is only
applicable to a certain disease. The best way is limit the exposure to asbestos.

There are no standard measures of treating mesothelioma since this disease develops is not fully
known except for the act that it develops from asbestos exposure. But still, the option for
treatment is not lacking: radiation therapy, chemotherapy, complementary and alternative
medicines, experimental therapies, surgery and even lifestyle modifications.

For asbestosis, like all other asbestos-related diseases, has no hope for cure yet but there are
measures that will help lessen the aggravation of the disease and of the symptoms. For minimal
discomforts, recommended medications are including drugs like ibuprofen and acetaminophen.
Oxygen supplementation could be administered for more severe cases of asbestosis.

For asbestos lung cancer, radiotherapy is the type of treatment that will focus on the early stage
of larynx cancer which typically combined with surgery. Chemotherapy is used for advanced
cases of larynx cancer. When the asbestos disease is already aggravated, there is really too little


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