The use of asbestos by human cultures dates as far back as 4,500 years ago, with the inhabitants of ancient Finland using anthophyllite fibers to make their cooking utensils. However, during the Industrial Revolution because of its cheap cost, its use became more widespread in the manufacturing of thousands of commercial products.
Over the past decade, scientists have recognized asbestos as a threat to human health, even though the use of asbestos was halted in the late 1970s. Unfortunately, the lives of many individuals continue to be adversely affected by previous asbestos exposure, since it can still be found in many factories, commercial buildings and homes. As a result, asbestos has been labeled a 'known human carcinogen'.
What is Asbestos?
According to the Centers for Disease Control and Prevention (CDC), asbestos is the commercial name given to a group of naturally occurring mineral silicates, which can be separated into flexible fibers. Asbestos is classified under two main mineralogical groups: serpentines and amphiboles.
Serpentine asbestos consists of only chrysotile asbestos, a white, hydrated magnesium silicate that has long wavy fibers, and accounts for 90% of the world’s consumption. In contrast, amosite, crocidolite, tremolite, anthophyllite and actinolite asbestos are categorized as amphibole asbestos, but only amosite and crocidolite are commercially used. Amosite has straight, short fibers and is brown in colour, while crocidolite is a blue fiber that is straight and long.
Health Effects
Asbestos is found in veins of its host rock and it is extracted for commercial use by open pit mining. This involves successive stages of crushing and aspiration of the ore. Within the past few decades, it was observed that persons who were exposed to asbestos had developed several different types of life threatening diseases.
Asbestos fibres are easily inhaled and carried into the lower regions of the lung causing fibrotic lung disease or asbestosis. This results in changes in the lining of the chest cavity (pleura) and can lead to reduced respiratory function and death. Additionally, the long-term inhalation of asbestos fibres can also increase the risk of lung cancer and mesothelioma.
Exposure Limits
According to the Occupational Safety and Health Administration (OSHA), the Permissible Exposure Limit (PEL) for asbestos is 0.1 fiber per cubic centimeter of air as an eight-hour time-weighted average (TWA), with an excursion limit (EL) of 1.0 asbestos fibers per cubic centimeter over a 30-minute period.
Sources of Asbestos in the Home and at the Workplace
The use of asbestos was widespread in the manufacturing of thousands of commercial products such as automotive brakes, cement and wallboard materials, insulation and fireproofing materials, and textile products. This was attributed to the fact that, when separated, asbestos fibers possessed highly desirable commercial physical properties such as flexibility, high tensile strength, electrical resistance, as well as resistance to chemical and thermal degradation.
Some of the common sources of asbestos in the home and at the work place may include:
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Building exteriors (siding panels, roof panels, building overhangs)
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Floorings (sheet vinyl flooring)
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Ceilings (ceiling tiles, drywall jointing materials)
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Walls (thermal spray, cement panels)
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Service areas like boiler rooms, machine rooms, fan rooms, crawl spaces (insulation on pipes and ducts)
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Pipes (domestic supply lines, drain lines, hot water supply lines)
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Fume hoods
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Lab counters
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Theatre curtains
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Duct tape
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Incinerators
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Incandescent light fixtures
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Wire insulation
Control Strategies for Reducing Asbestos Exposure in the Workplace