The industrialized history of asbestos.
Asbestos is a dangerous mineral, mined for its extensive use in commercial products. It has been linked to asbestosis (asbestos-derived lung disease), lung cancer, and mesothelioma, a rare and deadly cancer of the mesothelium. Despite previous efforts to ban asbestos use, it continues to be present in the manufacturing of commercial products.
The Beginning of It All
The history of asbestos dates back to ancient Greece and beyond, as accounts of its use ranged from the wicks of lanterns to tablecloths and funeral garments. (8) Its recorded use dwindled for thousands of years. Written off as a fascinating mineral with very little practical usage, asbestos lay quietly buried and forgotten. Then in the 1870s, a stroke of fortune occurred. A fire in Canada revealed large deposits of asbestos. Experts everywhere noted the tremendous resilience of the material, and once again, asbestos was in the spotlight. Asbestos was described as ".. a physical paradox that combined the properties of rock and silk and could be spun into strands that weighed less than an ounce to 100 yards." (1)
Emerging technology was the main reason that the properties of asbestos were reconsidered for industrial application. Around 1850, the world discovered the usefulness of the steam engine. A common problem with a steam engine was that, over time, the cotton piston seals would wear down, and steam would leak from the edges of the seals. Cotton was not impervious to heat, however, and as a result, steam engines experienced constant leaks. The industry was trying to find a long-term solution to this problem, but no material was strong enough to withstand the heat and pressure. With the re-discovery of asbestos rock in the Canadian fire, engineers considered asbestos to be the answer to their problems.
Geologists examined the new material and categorized asbestos into three types: chrysotile, crocidolite, and amosite--each displaying different beneficial properties. Chrysotile, which was impervious to heat and all liquids with the exception of strong acids, was the asbestos of choice due to its soft and pliable nature and its white color. Steam engine piston seals were now being packed with asbestos sealant, and the results were astounding. Not only did the asbestos packing remain unmarked by the pistons of the steam engine, but when disassembled after a period of time, the pistons showed no rust. The asbestos had protected the steel from rusting, while also keeping tight seals to prolong engine performance.
It was at this point, though, that factory workers began noticing the destructive tendency of this soft pliable material. In the areas of the engine where the asbestos came in contact, the steel had been worn down. This paradox, that the soft pliable asbestos was unmarked by the steel, but the hard steel was severely worn down from the asbestos, did not raise concerns, and the asbestos industry steamed on. Application after application, the soft, pliable, cotton-like material proved time and time again to be almost indestructible.
With its popularity steadily increasing, asbestos became a crucial ingredient in many products: asbestos found its way into cement, ceiling tiles, floor tiles, brake pads, fire retardant in mattress pads and, yes, even cigarette filters. With the rising concerns over the health implications of smoking, Kent cigarettes boasted about its new asbestos-lined "micronite" filter. (2)
What Exactly Is Asbestos?
The term "asbestos" designates a group of naturally occurring fibrous serpentine or amphibole minerals that have extraordinary tensile strength, conduct heat poorly, and are relatively resistant to chemical attack. (4) The principal varieties of asbestos are chrysotile, a serpentine mineral, and crocidolite, amosite, anthophyllite, tremolite, and actinolite, all of which are amphiboles. (4)
"Amphibole defines an important group of generally dark-colored, rock-forming inosilicate minerals composed of double chain SiO4 tetrahedra linked at the vertices and generally containing ions of iron and/or magnesium in their structures." (5) Amphiboles crystallize into two distinct systems, monoclinic and orthorhombic, and are similar to the pyroxenes.
The different forms of asbestos share very similar chemical structures as seen below:
Crocidolite: NaFe2 + 3Fe3 + 2Si8O22(OH)2
Chrysotile fibers consist of long, thin, flexible fibrils that resemble scrolls or cylinders. (5) Although chrysotile is a reasonably well-defined mineral (see photo 2), the other five amphibole asbestiform fibers are difficult to identify, as their physical and chemical properties are so vastly different. Each of the macroscopic asbestos fibers is actually a bundle of thinner fibers made up of fibrils. Chrysotile fibrils have a diameter of 20-25 nm. Each of these fibers decompose under weather conditions to the more dangerous smaller fibers associated with asbestos diseases.
The Growing Concern
With the ever-increasing number of factory workers exposed to asbestos dust, a certain number of these workers began coming down with symptoms suggesting an occupational hazard:
Dust was easily released during almost every process in the asbestos manufacture, especially in textiles, where fibers were whipped, pulled and twisted at high speed over rough guides, bobbins and rollers. The dusty trail began in the mines of Africa or Canada with the preliminary breaking down or opening of large clusters of fibers from the rock. The crude asbestos then arrived at the factory in Hessian sacks, where it was carried to a rotary mill, which continued the opening process by disintegrating (beating). Once the rock was fully separated, the fiber then passed to an enclosed machine for fiberizing, which finally delivered a flocculent soft and fibrous material. (1)
After only a short time on the job, workers began coming down with a dry hacking cough, sometimes producing a green and bloody sputum. Being in physical contact with the asbestos produced welts and eventually scars on the skin, which the workers termed "Asbestos Corns." Asbestos workers everywhere became afflicted with cardio-pulmonary diseases, which took their lives in sometimes a little as five years. With the growing number of illness-related deaths occurring in the asbestos industry, doctors everywhere began taking notice. In the early days of asbestos poisoning, a county doctor witnessed an autopsy. In the procedure, the deceased patient's lung was removed and dissected with a sharp scalpel. The doctor noted that after making the first cut through the lung, the scalpel's previously sharpened edge was severely damaged.
Before long, a correlation was drawn between asbestos and the lung disease that was being seen in asbestos plant workers everywhere. This new condition was termed "asbestosis" and occurred as a result of trauma inflicted on lung tissue from asbestos particles. Asbestosis has never been observed in relation to non-occupational asbestos exposure, (4) but mesothelioma caused by asbestos exposure has been seen in relatives and spouses exposed to the dust on the clothing brought home from the family factory worker. The duration of exposure required for asbestos to be dangerous is unclear, however, and at this time, any exposure is considered dangerous.
Why Is Asbestos Dangerous?
Asbestos is a natural mineral found in rock form (see photo 1). While encased, rock asbestos is harmless. However, when broken open for textile use, small microscopic fibers are released into the air. The suspended fibers can then be inhaled, and this is when asbestos becomes a health risk.
Airborne asbestos fibers are all different sizes, and the smaller the fiber, the more potentially dangerous. Not all asbestos fibers pose a danger when inhaled, and many are eliminated by the body's natural defense mechanisms. The lining in the nose and the mucociliary cells in the lungs are able to evacuate much of the larger fibers and deposit them in the throat. Phagocytes in the lungs can also engulf these particles and transport them to the lymphatics. Particles deposited in the throat can be coughed out or swallowed and eliminated through the bowels. The finest of the asbestos fibers are missed by the immune system and lodge themselves deep in the sensitive areas of the lungs--the respiratory bronchioles, the alveolar ducts, and, finally, the alveoli.
Once lodged in these sensitive areas, the asbestos fibers trigger pathological reactions. The phagocytes attempt to dissolve the fibers lodged in the lung tissue. This process causes extensive tissue damage to the surrounding lung tissue, but the asbestos remains unaffected. Over time, as the asbestos fibers break down in the lungs, they split and divide, working their way deeper into the lung tissue and sometimes through the lungs completely to surrounding tissues (see Photo 3). At this point, asbestos is considered highly dangerous and mesothelioma, a rare cancer of the mesothelium surrounding the organs of the body, becomes a serious concern. Asbestos fibers have the ability to burrow, and in some cases, these fibers will dig through the lung tissue and into the mesothelium surrounding the abdomen and other organs of the body. Its most common site is the pleura (outer lining of the lungs and chest cavity), but it may also occur in the peritoneum (the lining of the abdominal cavity) or the pericardium (a sac that surrounds the heart). (3) Once located in the mesothelium, asbestos aggravates the tissue, progressing quickly to cancer. In a study examining the carcinogenic effects of asbestos and its relationship to mesothelioma, it was established that through an alteration of the p14(ARF) or p53 cancer-inhibiting genes, malignant mesothelioma cells were able to circumvent an essential cell cycle checkpoint and continue to divide. The experiment, conducted on mice and on malignant mesothelioma tissue derived from human culture, showed that tissues of both species reacted the same way to asbestos fibers when the aforementioned genes were defective. Mice with certain gene combinations also showed accelerated and more aggressive cancer cell proliferation. (10) Without the exposure to asbestos, only one sample in the study showed spontaneous development of mesothelioma from gene manipulation. Mesothelioma is rarely acquired genetically but is most commonly seen from direct exposure to asbestos. Sadly, the mortality rate of mesothelioma is extremely high, with a life expectancy of six to 12 months after diagnosis, and currently, there are no successful treatments to prevent death. Cigarette smoking tends to accelerate lung cancer associated with asbestos exposure as the cigarette tar interferes with the body's ability to clear the asbestos fibers.
Besides the carcinogenic effects, asbestos can also attack the lung tissue itself, reducing air capacity. As more asbestos is inhaled over an extended period of time, the newly lodged fibers begin to infiltrate and surround the lung tissue in a "spider-web" type form. As these webs form, they destroy the lung's flexibility and literally form a strangulating hold on the lung tissue. This firming of the lung reduces the lung's capacity for air, and the afflicted individual is less and less able to inhale sufficient quantities, producing a "strangulating effect." This tremendous reduction in air capacity eventually makes it very difficult, if not impossible, to speak and eventually will result in death.
There Are Some Positives
Asbestos is not always dangerous when used properly, and most of the people afflicted with asbestosis are those working closely with asbestos daily. When asbestos is used for a product, which will remain untouched, such as a cement driveway or walls within a house, it remains harmless. House roofing materials made with asbestos provide terrific insulation from heat and cold and are fire resistant. The fire-resistant qualities of asbestos have saved many lives, and the incredible heat resistance has proven economical. Break pad linings made with asbestos remain cooler than metallic break linings and spare the break rotors from heat damage. With current factory technologies, it would be easy to automate the asbestos process, eliminating the dangers to factory workers. With asbestos limited to products that are not easily accessible or do not have to be maintained, the dangers of exposure decline.
How to Avoid Asbestos
Avoiding the products that are made with asbestos is the only sure way to avoid exposure. The following products can still be manufactured with asbestos: asbestos-cement corrugated sheet, asbestos-cement flat sheet, asbestos clothing, pipeline wrap, roofing felt, vinyl-asbestos floor tile, asbestos-cement shingle, millboard, asbestos-cement pipe, automatic transmission components, clutch facings, friction materials, disc brake pads, drum, brake linings, brake blocks, gaskets, non-roofing coatings, and roof coatings. (9) Certain items made with asbestos are particularly difficult to avoid, such as the brake pads found on certain cars. In these cases, direct exposure and inhalation should be avoided.
Wearing a mask will cut down exposure asbestos fibers. However, the microscopic asbestos fibers pass through most types of masks, and as a result, wearing one will only cut down exposure to the larger, less dangerous asbestos fibers. Homes built before 1975 can be screened for asbestos, and if asbestos is found, there are companies that can properly remove it. This process is expensive though and should be considered when purchasing an old house. Any clothing exposed to asbestos dust, mainly during occupational work, should be removed prior to entering the home. Certain clothing containing excessive amounts of asbestos dust should be discarded.
Asbestos is a marvelous mineral that can adapt to almost any application and has amazing properties to fight heat, cold, strain, and abrasion. Because of the inability to find a solution to so many problems related to the use of technology, asbestos seemed, at the time of its introduction, one answer. This passage, taken directly from the EPA website shows the battles that we still face today on asbestos use: "On July 12, 1989, EPA issued a final rule banning most asbestos-containing products. In 1991, this regulation was overturned by the Fifth Circuit Court of Appeals in New Orleans." (9) The final result was a court ruling restricting the use of asbestos to the aforementioned products.
Because most of the individuals susceptible to asbestos disease are those working directly with asbestos, the above products continue to propagate asbestosis and asbestos-related cancers in this population. Initially, in the construction of these products, the dangers can be minimized with proper factory procedures. The maintenance on these products, however, poses a serious threat for those involved. When looking at asbestos break pads, for instance, as the brake pads break down from use, dangerous fibers are released in brake dust. When these brake pads require maintenance, the technician exposed to this dust is inevitably exposed to the asbestos fibers.
It is critical to remember that the dangerous asbestos fibers are the microscopic fibers, which evade not only the immune system, but also most masks worn by technicians. These fibers can be suspended in the air for extended periods and, even after settling, can be stirred up easily and re-suspended. This makes the use of asbestos not only dangerous but also highly impractical, as proper asbestos removal requires tremendous procedures.
Many of the corporations that introduced asbestos into the marketplace have long since gone out of business, but many companies still walk the fine line of asbestos use in their products. Since profits outweigh lawsuit expenses, many companies keep using asbestos with very little concern for the people handling it.
The exposure to asbestos is no less dangerous than it was one hundred years ago, and we must remember that with every exposure, the potential for cancer is there. Keeping this in mind, asbestos usage should be discontinued, as the benefits do not outweigh the risks.
1. Asbestos plant--smokers charge cigarette's asbestos cigarette filter caused cancer. In A Physical Paradox. London, England: Oxford University Press; 2008. Available at: http://www.oup.co.uk/pdf/0-19-829690-8.pdf2.
2. Catanoso J. Washington Monthly. Jan-Feb 1993. Available at: http://www.findarticles.com/p/articles/mi_m1316/is_n1-2_v25/ai_13320122.
3. USEPA Office of Air Quality Planning and Standards, "Asbestos: Health and Exposure." US EPA Office of Pollution Prevention and Toxics, NCPD
4. Air Quality Guidelines, Section 6.2. Asbestos. World Health Organization. 2000. Available at: http://www.euro.who.int/air/activities/20050223_4. Accessed February 21, 2008.
5. Definition of Amphibole. Available at: http://en.wikipedia.org/wiki/Amphibole. Accessed February 21, 2008.
6. Photo of Chrysotile rock. Available at: http://en.wikipedia.org/wiki/Image:Asbestos1USGOV.jpg. Accessed February 21, 2008.
7. Natural Asbestos rock photo. Available at: www.arb.ca.gov/toxics/asbestos/images/poprock.jpg. Accessed February 21, 2008.
8. Asbestos. Available at: http://en.wikipedia.org/wiki/Asbestos. Accessed February 21, 2008.
9. EPA Asbestos Materials Bans: Clarification. U.S. Environmental Protection Agency. Available at: http://www.mde.state.md.us/assets/document/Air/asb-bans.pdf. Accessed February 20, 2008.
10. Altomare DA, et al. A mouse model recapitulating molecular features of human mesothelioma. Cancer Res. 2005; 65: (18). Available at: http://cancerres.aacrjournals.org/cgi/content/full/65/18/8090.
Justin Taylor graduated in 1995 from Eastern Michigan University with a degree in Telecommunications. While in school, Justin worked at local group homes for the severely disabled as a direct care specialist. After graduating from EMU, Justin worked in the printing and advertising industry for three years before deciding to go back to school for health care; his first love. Justin enrolled at Arizona State University in the nursing program with a goal of becoming a nurse practitioner. A year away from graduation, a presentation was given at ASU about Naturopathic Medicine, and Justin immediately recognized the wonderful possibilities of this ever-evolving career field. Justin left ASU nursing school and enrolled at the Southwest College of Naturopathic Medicine where he is currently finishing his third year. Justin received an award of excellence in his presentation of the genetic mutation of P-53 genes and their relationship to cancer.
"Asbestos ... The world's most wonderful mineral." A.L. Summers, Asbestos and the Asbestos Industry (1919)
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|Date:||May 1, 2008|
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