Showing posts with label asbestos. Show all posts
Showing posts with label asbestos. Show all posts

What Is Asbestos?

Asbestos is a mineral fibre. It can be positively identified only with a special type of microscope. There are several types of asbestos fibers. In the past, asbestos was added to a variety of products to strengthen them and to provide heat insulation and fire resistance.
The word "unquenchable" is the Greek word "asbestos" which has also become an English word. The English word "asbestos" means, according to Webster's Dictionary "a kind of material unaffected by fire." This is a very different meaning than the "religious" meaning of the word and different than the way the Greeks used the word in Jesus' day.

How Can Asbestos Affect My Health?
From studies of people who were exposed to asbestos in factories and shipyards, we know that breathing high levels of asbestos fibers can lead to an increased risk of:

  • lung cancer;
  • mesothelioma, a cancer of the lining of the chest and the abdominal cavity;
  • and asbestosis, in which the lungs become scarred with fibrous tissue.
The risk of lung cancer and mesothelioma increases with the number of fibers inhaled. The risk of lung cancer from inhaling asbestos fibers is also greater if you smoke. People who get asbestosis have usually been exposed to high levels of asbestos for a long time. The symptoms of these diseases do not usually appear until about 20 to 30 years after the first exposure to asbestos.

Most people exposed to small amounts of asbestos, as we all are in our daily lives, do not develop these health problems. However, if disturbed, asbestos material may release asbestos fibers, which can be inhaled into the lungs. The fibers can remain there for a long time, increasing the risk of disease. Asbestos material that would crumble easily if handled, or that has been sawed, scraped, or sanded into a powder, is more likely to create a health hazard.

What are the dangers of asbestos exposure to workers?


The inhalation of asbestos fibers by workers can cause serious diseases of the lungs and other organs that may not appear until years after the exposure has occurred. For instance, asbestosis can cause a buildup of scar-like tissue in the lungs and result in loss of lung function that often progresses to disability and death. Asbestos fibers associated with these health risks are too small to be seen with the naked eye, and smokers are at higher risk of developing some asbestos-related diseases.

Asbestosis?

Asbestosis is a chronic inflammatory medical condition affecting the parenchymal tissue of the lungs. It occurs after long-term, heavy exposure to asbestos, e.g. in mining, and is therefore regarded as an occupational lung disease. Sufferers have severe dyspnea (shortness of breath) and are at an increased risk regarding several different types of lung cancer.
As clear explanations are not always stressed in non-technical literature, care should be taken to distinguish between several forms of relevant diseases. According to the World Health Organisation (WHO), these may be defined as; asbestosis (the subject of this article), lung cancer, and mesothelioma (generally a very rare form of cancer, but increasing in frequency as people exposed to asbestos age).

The primary symptom of asbestosis is generally the slow onset of shortness of breath on exertion. In severe, advanced cases, this may lead to respiratory failure. Coughing is not usually a typical symptom, unless the patient has other, concomitant respiratory tract diseases.
People with extensive occupational exposure to the mining, manufacturing, handling or removal of asbestos are at risk of developing asbestosis. There is also an increased risk of lung cancer and mesothelioma. Asbestosis and lung cancer require prolonged exposure to asbestos. However, cases of mesothelioma have been documented with even 1-3 months of exposure, and only indirect exposure (through air ventilation system.) Most cases of asbestosis do not become apparent until 5-10 years after the initial exposure to the material.

Asbestos : historic usage

Asbestos was named by the ancient Greeks who also recognized certain hazards of the material.The Greek geographer Strabo and the Roman naturalist Pliny the Elder noted that the material damaged lungs of slaves who wove it into cloth. Charlemagne, the first Holy Roman Emperor, is said to have had a tablecloth made of asbestos.

Wealthy Persians, who bought asbestos imported over the Hindu Kush, amazed guests by cleaning the cloth by simply exposing it to fire. According to Biruni in his book of Gems, any cloths made of asbestos (Persian: آذرشست, āzarshast or Persian: آذرشب, āzarshab) were called (Persian: شستكه) shastakeh. Some of the Persians believed the fiber was fur from an animal (named samandar, Persian: سمندر) that lived in fire and died when exposed to water.
Some archeologists believe that ancients made shrouds of asbestos, where in they burned the bodies of their kings, in order to preserve only their ashes, and prevent their being mixed with those of wood or other combustible materials commonly used in funeral pyres.
Others assert that the ancients used asbestos to make perpetual wicks for sepulchral or other lamps. In more recent centuries, asbestos was indeed 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.
Asbestos became more widespread during the industrial revolution; in the 1860s it was used as insulation in the U.S. and Canada. Development of the first commercial asbestos mine began in 1879 in the Appalachian foothills of Quebec. By the mid 20th century uses included fire retardant coatings, concrete, bricks, pipes and fireplace cement, heat, fire, and acid resistant gaskets, pipe insulation, ceiling insulation, fireproof drywall, flooring, roofing, lawn furniture, and drywall joint compound.
Approximately 100,000 people in the United States have died, or will die, from asbestos exposure related to ship building. In the Hampton Roads area, a shipbuilding center, mesothelioma occurrence is seven times the national rate.Thousands of metric tons of asbestos were used in World War II ships to wrap the pipes, line the boilers, and cover engine and turbine parts. There were approximately 4.3 million shipyard workers in the United States during WWII; for every thousand workers about fourteen died of mesothelioma and an unknown number died from asbestosis.
Asbestos fibers were once used in automobile brake pads and shoes. Since the mid-1990s, a majority of brake pads, new or replacement, have been manufactured instead with linings made of ceramic, carbon, metallic and Aramid fiber (Twaron or Kevlar—the same material used in bulletproof vests).
Kent, the first filtered cigarette on the market, used crocidolite asbestos in its "Micronite" filter from 1952 to 1956.
The first documented death related to asbestos was in 1906.In the early 1900s researchers began to notice a large number of early deaths and lung problems in asbestos mining towns. The first diagnosis of asbestosis was made in England in 1924. By the 1930s, England regulated ventilation and made asbestosis an excusable work related disease, about ten years sooner than the U.S.The term Mesothelioma was not used in medical literature until 1931, and was not associated with asbestos until sometime in the 1940s.
The United States government and asbestos industry have been criticized for not acting quickly enough to inform the public of dangers, and to reduce public exposure. In the late 1970s court documents proved that asbestos industry officials knew of asbestos dangers and tried to conceal them.
In Japan, particularly after World War II, asbestos was used in the manufacture of ammonium sulfate for purposes of rice production, sprayed upon the ceilings, iron skeletons, and walls of railroad cars and buildings (during the 1960s), and used for energy efficiency reasons as well. Production of asbestos in Japan peaked in 1974 and went through ups and downs until about 1990, when production began to drop severely.

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