Asbestos: An Overview


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General facts relating to asbestos and asbestos exposure.

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Asbestos: An Overview

  1. 1. ASBESTOS An Overview
  2. 2. What Is Asbestos? <ul><li>Silicate minerals – naturally occuring </li></ul><ul><li>Separates into long flexible fibers </li></ul><ul><li>Fireproof, used to resist heat and corrosion </li></ul><ul><li>Non-conducting </li></ul><ul><li>Chemically resistant </li></ul>
  3. 3. Six Minerals Defined as Asbestos <ul><li>Chrysotile </li></ul><ul><li>Amosite </li></ul><ul><li>Crocidolite </li></ul><ul><li>Tremolite </li></ul><ul><li>Anthophyllite </li></ul><ul><li>Actinolite </li></ul>
  4. 4. Chrysotile <ul><li>Mg 3 (Si 2 O 5 )(OH) 4 </li></ul><ul><li>Routes of exposure include absorption by inhalation </li></ul><ul><li>Long-term exposure is linked to pulmonary fibrosis and mesothelioma </li></ul><ul><li>Serpentine series </li></ul>
  5. 5. Amosite <ul><li>(FeC 2 + Mg) 6 ·Si 8 O 22 (OH) 2 </li></ul><ul><li>Routes of exposure include skin contact, inhalation, and ingestion </li></ul><ul><li>Known human carcinogen </li></ul><ul><li>Amphibole Series </li></ul>
  6. 6. Crocidolite <ul><li>Na 2 O·Fe 2 O 3 ·3FeO·8SiO 2 ·H 2 O </li></ul><ul><li>Routes of exposure include inhalation, skin contact, and ingestion </li></ul><ul><li>Known human carcinogen – most hazardous of amphibole series </li></ul>
  7. 7. Tremolite <ul><li>Ca2Mg5Si8O22(OH)2 </li></ul><ul><li>Associated with Vermiculite </li></ul><ul><li>Found in Libby, Montana </li></ul><ul><li>Sold as housing insulation </li></ul><ul><li>Sold as soil conditioner </li></ul><ul><li>Recently discovered in CSI: Crime Scene Investigation Fingerprint Examination Kit </li></ul>
  8. 8. Anthophyllite <ul><li>(Mg, Fe)7Si8O22(OH)2 </li></ul><ul><li>Some forms are fibrous and used as asbestos </li></ul><ul><li>Used in refractory cements </li></ul><ul><li>Known human carcinogen </li></ul><ul><li>Found in talc </li></ul>
  9. 9. Actinolite <ul><li>Ca 2 (Mg,Fe) 5 Si 8 O 22 (OH) 2 </li></ul><ul><li>Fibrous varieties used in industrial applications </li></ul><ul><li>Once used as insulator, but was banned because it caused cancer </li></ul>
  10. 10. Effects of Asbestos Exposure <ul><li>Mesothelioma – cancer of the mesothelium </li></ul><ul><li>Asbestiosis – breathing disorder </li></ul><ul><li>and </li></ul><ul><li>Lung Cancer </li></ul>
  11. 11. Mesothelioma <ul><li>Approximately 2000 cases per year are diagnosed in the United States </li></ul><ul><li>Occurs more often in men than women </li></ul><ul><li>A history of working with asbestos is reported in 70-80 percent of all cases </li></ul><ul><li>Symptoms may appear 30 to 50 years after exposure </li></ul>
  12. 13. Asbestiosis <ul><li>Breathing disorder caused by inhaling asbestos </li></ul><ul><li>Can cause scarring of lung tissue and shortness of breath </li></ul><ul><li>Symptoms range from mild to severe </li></ul><ul><li>Using safety precautions limits likelihood of contracting asbestiosis </li></ul>
  13. 14. Symptoms Safety Precautions <ul><li>Shortness of breath </li></ul><ul><li>Coughing </li></ul><ul><li>Chest pain </li></ul><ul><li>Decreasing tolerance for physical activity </li></ul><ul><li>Permanent lung damage </li></ul><ul><li>Call professional to remove </li></ul><ul><li>Wear safety equipment provided by your employer </li></ul><ul><li>Respiratory air masks </li></ul><ul><li>Gloves </li></ul><ul><li>Protective eyewear </li></ul>
  14. 15. Lung Cancer <ul><li>Symptoms include: </li></ul><ul><ul><li>Persistent Cough </li></ul></ul><ul><ul><li>Chest Pain </li></ul></ul><ul><ul><li>Weight Loss </li></ul></ul><ul><ul><li>Loss of appetite </li></ul></ul><ul><ul><li>Bloody or rust colored phlegm </li></ul></ul><ul><ul><li>Recurring bronchitis or pneumonia </li></ul></ul><ul><ul><li>Wheezing </li></ul></ul>
  15. 16. Healthy Lung Cancerous Lung
  16. 17. Vulnerable Industries <ul><li>Shipbuilding </li></ul><ul><li>US Navy </li></ul><ul><li>Construction </li></ul><ul><li>Insulation </li></ul><ul><li>Oil & Chemical </li></ul><ul><li>Power Plant </li></ul><ul><li>Railroad </li></ul><ul><li>Automotive </li></ul><ul><li>Steel/metal </li></ul><ul><li>Asbestos manufacturing </li></ul><ul><li>Paper Mill </li></ul><ul><li>Ceramics/Glass </li></ul>
  17. 18. Vulnerable Occupations <ul><li>Pipefitter </li></ul><ul><li>Boilermaker </li></ul><ul><li>Maintenance </li></ul><ul><li>Machinist </li></ul><ul><li>Electrician </li></ul><ul><li>Sheet metal </li></ul>
  18. 19. Non Occupational Exposure <ul><li>Contact with asbestos worker </li></ul><ul><li>Proximity to asbestos mining operations </li></ul><ul><li>Long term exposure in buildings constructed with asbestos materials </li></ul>
  19. 20. Uses for Asbestos: 1950’s through the 1970’s <ul><li>Building materials </li></ul><ul><li>Roofing tiles </li></ul><ul><li>Pipe insulation </li></ul><ul><li>Brake liners </li></ul><ul><li>Fireproof clothing </li></ul><ul><li>Oven mitts </li></ul>
  20. 21. Asbestos in Drinking Water <ul><li>Asbestos was used in concrete pipes that transport water </li></ul><ul><li>Asbestos fibers bind the concrete and made the pipes lighter and easier to install </li></ul><ul><li>25% asbestos: 75% concrete </li></ul><ul><li>Originally intended to be used for irrigation </li></ul><ul><li>Cheap materials and readily available </li></ul><ul><li>Used in municipalities across the US and Canada </li></ul><ul><li>There is an estimated 200,000 miles of asbestos/concrete pipe across the USA </li></ul>
  21. 22. Can asbestos that is swallowed cause cancer? <ul><li>Scientific studies to answer this question were conducted in the 1970s and 1980s </li></ul><ul><li>Animal models and “natural experiments” were used </li></ul><ul><li>Direct injection used in animal models included rats injected with asbestos directly into body cavities caused tumors </li></ul>
  22. 23. Direct Injection: Effects <ul><li>41 rats injected with asbestos in the lung cavity </li></ul><ul><li>5 developed mesotheliomas in the abdomen </li></ul><ul><li>20 developed mesotheliomas of the lining of the lung cavity </li></ul>
  23. 24. Direct Injection: Effects cont <ul><li>20 hamsters injected in the abdominal cavity </li></ul><ul><li>15 developed abdominal tumors </li></ul><ul><li>Rabbits injected with asbestos in the abdominal cavity developed tumors within 5 to 6 years </li></ul><ul><li>Monkeys developed asbestiosis and precancerous lesions after injections into the trachea and pleura </li></ul>
  24. 25. Conclusions of Direct Injection through 1983 <ul><li>Direct application into the body will cause cancer in animals </li></ul><ul><li>It is likely that asbestos fibers can migrate to other tissues </li></ul><ul><li>There are both positive and negative studies </li></ul><ul><li>There is a question of the suitability of animal studies as they relate to humans </li></ul>
  25. 26. Humans and Oral Exposure to Asbestos <ul><li>Studies conducted using those humans who have been inadvertently exposed </li></ul><ul><li>Comparisons made in communities with known and substantial amounts of asbestos in drinking water versus communities believe to have less exposure </li></ul><ul><li>Information found to be inadequate to determine a credible risk of cancer due to asbestos in drinking water </li></ul>
  26. 27. Recommendations to limit exposure by ingestion <ul><li>Eliminate asbestos cement pipe in water systems </li></ul><ul><li>Eliminate the use of asbestos filters in processing beverages and pharmaceuticals </li></ul><ul><li>Reduce asbestos fibers in drinking water supplies </li></ul><ul><li>January 29, 1986 – EPA proposed a prohibition of the manufacture of asbestos /cement pipe </li></ul>
  27. 28. Studies from 1980s until 2005 <ul><li>A baboon was given asbestos orally and was found to have asbestos fibers in the spleen, stomach, heart, pancreas and blood </li></ul><ul><li>Rats given asbestos fibers while pregnant had transmitted asbestos fibers to their pups </li></ul>
  28. 29. Woodstock, New York <ul><li>Study published in 2005 </li></ul><ul><li>Examined incidence of cancer between 1980 and 1998 </li></ul><ul><li>Town water asbestos contamination </li></ul><ul><li>304.5 million asbestos fibers from asbestos/ concrete pipes </li></ul><ul><li>Pipes installed in 1950; discovered in 1985 </li></ul>
  29. 30. The Study: Woodstock, NY <ul><li>1852 people analyzed </li></ul><ul><li>Cancer rates observed between 1980 – 1998 </li></ul><ul><li>Follow-up from 5 to 20 years </li></ul><ul><li>Comparison was with New York State and did not include New York City </li></ul><ul><li>Pancreatic cancer was the only significant increase </li></ul><ul><li>Small numbers in study and minimal latency period affected validity of conclusions </li></ul>
  30. 31. References <ul><li>Berry, M. (1996) Mesothelioma Incidence and Community Asbestos Exposure, Environmental Research 75, 34-40, 1997 </li></ul><ul><li>Browne, M. L., D. Varadarajulu, E. Lewis-Michl, and E. F. Fitzgerald (2004) Cancer incidence and asbestos in drinking water, Town of Woodstock, New York, 1980-1998, Environmental Research (2005), 224-232 </li></ul><ul><li>Jacobs, D. E. (2005) A qualitative review of housing hazard assessment protocols in the United States, Environmental Research (2006), 13-21 </li></ul><ul><li>Longley, A (ND) Asbestos in drinking water, Pacific Sciences Institute, Seattle, Washington </li></ul><ul><li>Mineralogy database, updated 3/8/2009, accessed in May 2009 at </li></ul><ul><li>Occupational Safety and Health Administration (2002) OSHA Fact Sheet accessed on May 15, 2009 at </li></ul><ul><li>Roggli, V. L., T. D. Oury, T. A. Sporn (2004) Pathology of asbestos-associated disease, 2 nd edition, Springer </li></ul>