- - Mesothelioma Survival Information

Monday, January 17, 2011

ASBESTOS USED

Asbestos has been mined and used commercially in North America since the late 1800s. Its use increased greatly during World War II (Ullrich RL. Etiology of cancer: Physical factors. In: DeVita VT Jr., Hellman S, Rosenberg SA, editors. Cancer: Principles and Practice of Oncology. Vol. 1 and 2. 7th ed. Philadelphia: Lippincott Williams and Wilkins, 2004 and 3). Since then, asbestos has been used in many industries. For example, the building and construction industries have used it for strengthening cement and plastics as well as for insulation, roofing, fireproofing, and sound absorption. The shipbuilding industry has used asbestos to insulate boilers, steam pipes, and hot water 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.
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 fibers in these products could be released into the environment during use. In addition, manufacturers of electric hairdryers voluntarily stopped using asbestos in their products in 1979. In 1989, the U.S. Environmental Protection Agency (EPA) banned all new uses of asbestos; however, uses developed before 1989 are still allowed. The EPA 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 (2).
In June 2000, the CPSC concluded that the risk of children’s exposure to asbestos fibers in crayons was extremely low (1). However, U.S. manufacturers of these crayons agreed to eliminate talc from their products.
In August 2000, the EPA conducted a series of tests to evaluate the risk for consumers of adverse health effects associated with exposure to asbestos-contaminated vermiculite. The EPA concluded that exposure to asbestos from some vermiculite products poses only a minimal health risk. The EPA recommended that consumers reduce the low risk associated with the occasional use of vermiculite during gardening activities by limiting the amount of dust produced during vermiculite use. Specifically, the EPA suggested that consumers use vermiculite outdoors or in a well-ventilated area; keep vermiculite damp while using it; avoid bringing dust from vermiculite into the home on clothing; and use premixed potting soil, which is less likely to generate dust (2).
The regulations described above and other actions, coupled with widespread public concern about the health hazards of asbestos, have resulted in a significant annual decline in the U.S. use of asbestos. Domestic consumption of asbestos amounted to about 803,000 metric tons in 1973, but it had dropped to about 2,400 metric tons by 2005 (3, 5).

(source : www.cancer.gov – National Cancer Institute, U.S. National Institutes of Health)

Monday, December 27, 2010

ASBESTOS RAW MATERIALS


There are six types of asbestos: actinolite , amosite, anthophyllite , crocidolite, tremolite , and chrysolite . The first five types are called as amphiboles. They are defined by having very hard and loaded fibers, which cause them a dangerous health hazard. Amphibolic asbestos fibers can penetrate body tissue, especially in the lungs, and eventually cause tumors to cause grow. The sixth type of asbestos, chrysotile , is known as a serpentine . Its fibers are much softer and more adjustable than amphibolic asbestos, and they do lower harm to body tissue. All six types of asbestos are compiled of long chains of silicon and oxygen atoms, locked together with various metals, such as magnesium and iron, to form the whisker-like crystalline fibers that characterize this mineral.
Chrysotile is the most commonly used type of asbestos and accounted for about 98% of the worldwide asbestos production in 1988. It's usually white, and is sometimes called white asbestos, although it can also be amber, gray, or greenish in color. Most chrysotile fibers are about 0.25-0.50 in (6.4-12.7 mm) long and are usually expanded to concrete mixes to provide reinforcement. Only about 8% of chrysotile fibers are long enough to comprise whirled into fabric or rope.
Amosite, sometimes called brown asbestos, accounted for about 1% of worldwide production in 1988. It often has aflame brown tinge , but is also found in dark colors, as well as white. Amosite has coarse fibers that are about 0.12-6.0 in (3.0-152.0 mm) long. The fibers are difficult to spin into fabric or rope and are mostly used as an insulant , although that use is banned in many countries.
Crocidolite, sometimes called blue asbestos , accounted for the remaining 1% of global production. It has a bluish tinge, and its fibers are about 0.12-3.0 in (3.0-76.0 mm) long. Crocidolite has very high tensile strength and excellent resistance to chemicals. Among its uses is as a reinforcement in plastics.
The other three types of asbestos-anthophyllite, actinolite, and tremolite-have no significant commercial applications and are seldom well-mined.

Friday, December 10, 2010

ASBESTOS BASED MATERIALS

Asbestos is the name given to a number of naturally occurring fibrous minerals with high tensile strength, the ability to be woven, and resistance to heat and most chemicals. Because of these properties, asbestos fibers have been used in a wide range of manufactured goods, including roofing shingles, ceiling and floor tiles, paper and cement products, textiles, coatings, and friction products such as automobile clutch, brake and transmission parts. The Toxic Substances Control Act defines asbestos as the asbestiform varieties of: chrysotile (serpentine); crocidolite (riebeckite); amosite (cummingtonite/grunerite); anthophyllite; tremolite; and actinolite.


 

The product may contain asbestos :


 

Product 

Location 

% Asbestos Content

Asbestos

Date of Use 

Roofing and Siding 

Roofing felts

Flat, built up roofs

10-15

1910-present

Roof felt shingles

Roofs

1

1971-1974

Roofing shingles

Roofs

20-32

Unknown-present

Roofing Tiles

Roofs

20-30

1930-present

Siding shingles 

Siding 

12-14 

Unknown-present

Clapboards 

Siding 

12-15 

1944-1945 

Walls & Ceilings 

Sprayed coating 

Ceilings, walls, and steelwork

1-95

1935-1978

Troweled coating

Ceilings, walls

1-95

1936-1978

Asbestos-cement sheet

Near heat sources such as fireplaces, boilers

20-50

1930-present

Spackle

Walls, ceilings

3-5

1930-1978

Joint compounds

Walls, ceilings

3-5

1945-1977

Textured paints

Walls, ceilings

4-15

Unkown-1978

Millboard, rollboard

Walls, commercial buildings

80-85

1925-Unknown

Vinyl wallpaper 

Walls 

6-8 

Unknown

Insulation board 

Walls 

30 

Unnown

Floors 

Vinyl-asbestos tile 

Floors 

21 

1950-1980? 

Asphalt-asbestos tile 

Floors 

26-33 

1920-1980? 

Resilient sheet flooring 

Floors 

30 

1950-1980? 

Mastic adhesives

Sheet flooring and tile backing

5-25

1945-1980?

Pipes & Boilers 

Cement pipe and fittings

Water and sewer mains

20-?

1935-present

Block insulation

Boilers

6-15

1890-1978

Preformed pipe wrap 

Pipes 

50 

1926-1975 

Corrugated asbestos paper 

Pipes, high temperature, moderate temperature

90
35-70

1935-1980?
1910-1980?

Paper tape 

Furnaces, steam valves, flanges, electrical wiring 

80 

1901-1980? 

Putty (mudding) 

Plumbing joints 

20-100 

1900-1973 

Other Products 

Gaskets/Packing 

Pipe flanges, boiler doors, valves, pumps

10-80 

1900-1980s 

Cloth/Blankets 

Welding accessory, pipe insulation, curtains, clothing 

40-100 

1900-1985 

Clothing (gloves, mittens, sleeves, aprons, coats, jackets, pants, hoods, spats) 

Heat and fire resistant protective clothing 

40-100

1900-1985 

Cement/Mortar

Used as a castable insulation on furnaces, pipes, boilers, brick

5-100

1900-1975

Metal-Clad Firebrick

Found in Open Health Furnaces and Basic Oxygen Furnaces

10

1950-1980s

Gunnite/Fire-proofing spray

Sprayed onto furnaces as well as structural steel for fireproofing protection

20-75

1900-1980s

Hot-Tops (ingot mold covers and inserts) 

Used with ingot molds in the steel pouring process 

10-80 

1960-1980 


 

Friday, November 19, 2010

DEFINITION OF ASBESTOS

Literally, Asbestos is a name for a variety of fibrous minerals found naturally in rock formations around the world. Because asbestos fibres are strong, durable and non-combustible, they were widely used by industry, mainly in construction and friction materials.
Asbestos applies to several types of fibrous silicate minerals. Historically, asbestos is best known for its resistance to flame and its ability to be woven into cloth. Because of these properties, it was used to make fireproof stage curtains for theaters, as well as heat-resistant clothing for metal workers and firefighters. More modern applications of asbestos take advantage of its chemical resistance and the reinforcing properties of its fibers to produce asbestos-reinforced cement products including pipes, sheets, and shingles used in building construction. Asbestos is also used as insulation for rocket engines on the space shuttle and as a component in the electrolytic cells that make oxygen on submerged nuclear submarines. Much of the chlorine for bleach, cleansers, and disinfectants is produced using asbestos products.
The earliest known use of asbestos was in about 2500 B.C. in what is now Finland, where asbestos fibers were mixed with clay to form stronger ceramic utensils and pots. The first written reference to asbestos came from Greece in about 300 B.C. when Theophrastus, one of Aristotle's students, wrote a book entitled On Stones. In his book, he mentioned an unnamed mineral substance, which looked like rotten wood, yet was not consumed when doused with oil and ignited. The Greeks used it to make lamp wicks and other fireproof items. When the Roman naturalist and statesman Pliny the Elder wrote his comprehensive Natural History in about 60 A.D., he described this fire-proof mineral and gave it the name asbestinon, meaning unquenchable, from which we get the English word asbestos.
Although the fireproof qualities of asbestos continued to fascinate the scientific community for hundreds of years, it wasn't until the 1800s that asbestos found many commercial uses. The first United States patent for an asbestos product was issued in 1828 for a lining material used in steam engines. In 1868 Henry Ward Johns of the United States patented a fireproof roofing material made of burlap and paper laminated together with a mixture of tar and asbestos fibers. It became an immediate success. Large-scale mining of asbestos deposits near Quebec, Canada, began in 1878 and spurred the development of other commercial uses. By 1900 asbestos was being used to make gaskets, fireproof safes, bearings, electrical wiring insulation, building materials, and even filters to strain fruit juices.
Technological developments in the early 1900s resulted in even more uses for asbestos. Many of the early plastic materials relied on asbestos fibers for reinforcement and heat resistance. Vinyl-asbestos tile became one of the most commonly used floor coverings and remained in use well into the 1960s. Automobile brake linings and clutch facings also used large amounts of asbestos, as did a multitude of building materials. After World War II, the use of asbestos in products continued to expand. Heart surgeons used asbestos thread to close incisions, Christmas trees were decorated with asbestos artificial snow, and a brand of toothpaste was marketed using asbestos fibers as an abrasive.
The widespread use of asbestos was not without a dark side, however. Health problems associated with exposure to airborne asbestos particles had been noted since the early 1900s, and resulted in the passage of the Asbestos Industry Regulations of 1931 in England. By the mid-1960s, health problems began to surface among shipyard workers who handled asbestos insulation during World War II. In the United States, the problem reached the crisis stage by the 1970s, forcing the Environmental Protection Agency (EPA) to place severe restrictions on the use of asbestos. Although the EPA lifted the ban for certain kinds of asbestos in 1991, the public's faith had been severely shaken, and most manufacturers had voluntarily removed asbestos from their products. As a result, asbestos usage in the United States fell from about 880,000 tons/yr (800,000 metric tons/yr) in 1973 to less than 44,000 tons/yr (40,000 metric tons/yr) in 1997.
In other countries, asbestos products are still widely used, especially in the construction industry. Worldwide usage of asbestos in 1997 was estimated at about 2.0 million tons/yr (1.8 million metric tons/yr). Most of this asbestos is used to make asbestos-reinforced concrete products, where the asbestos fibers are locked within the concrete.
Asbestos mining operations are found in 21 countries. The leading producers of asbestos are Russia (formerly the USSR), Canada, Brazil, Zimbabwe, China, and South Africa. Smaller deposits are found in the United States and several other countries.

Sunday, November 14, 2010

THE FACT OF ASBESTOS

Asbestos has been used for more than 2,000 years. It was named by the Ancient Greeks, its name meaning "INEXTINGUISHABLE". The Greeks also noted its harmful biological effects. Even though Strabo (a Greeks Geographer) and Pliny (a Roman Naturalist) the Elder both observed the "sickness of the lungs" in the slaves that wove asbestos into cloth, they were in such awe of asbestos seemingly magical properties that they ignored the symptoms.
The Greeks used asbestos for the wicks of the eternal flames of the vestal virgin, as the funeral dress for the cremation of kings, and as napkins. It is rumoured that Romans would clean asbestos napkins by throwing them in the fire. The asbestos cloth would come out of the fire whiter than it went in, so the Romans named asbestos "AMIANTUS", meaning "unpolluted".
Use of asbestos declined during the Middle Ages, yet some say that Charlemagne had asbestos tablecloths. Marco Polo was also shown items made from asbestos cloth on his travels.
Asbestos use was brought back in the 1700s, but did not become popular until the Industrial Revolution during the late 1800s. It then began to be used as insulation for pipes, turbines, boilers, kilns, oven, and other high-temperature products. Ancient observations of the health risk of asbestos were either forgotten or ignored.
At the turn of the twentieth century, researchers began to notice a large number of deaths and lung problems in asbestos mining towns. In 1917 and 1918, it was observed by several studies in the United States that asbestos workers were dying unnaturally young.
The first diagnosis of asbestosis was made in 1924. A woman had been working with asbestos since she was thirteen. She died when she was thirty-three years old, and an English doctor determined that the cause of death was what he called "asbestosis".  Because of this, a study was done on asbestos workers in England. Twenty-five percent of them showed evidence of asbestos-related lung disease. Laws were passed in 1931 to increase ventilation and to make asbestosis an excusable work-related disease. It would take the United States ten more years to make these steps.

In the 1930s major medical journals began to publish articles that linked asbestos to cancer. The re-discovery of asbestos-related diseases were put on the back burner for several years due to the emergence of silicosis (a lung disease caused by silica dust inhalation). The affected workers brought $300 million in lawsuits against their employers. This served as a warning to the asbestos companies, and afterwards they tried to cover up the health effects of asbestos. Asbestos companies continued to use asbestos in manufacturing and construction. Despite that many materials, such as fiberglass insulation, were created to replace asbestos, companies that used asbestos ignored the safer alternatives. They ignored the danger for the sake of profits, much like the tobacco industry. The conduct of the asbestos companies is especially egregious, however, because the victims were largely exploited workers who were unaware of the serious health risks they were exposed to on a daily basis.

Twitter Delicious Facebook Digg Stumbleupon Favorites More

 
Powered by Blogger