Asbestos: An Overview
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Asbestos: An Overview

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General facts relating to asbestos and asbestos exposure.

General facts relating to asbestos and asbestos exposure.

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Asbestos: An Overview Asbestos: An Overview Presentation Transcript

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