GEOL 100 (Planet Earth) Topic #6 - Asbestos: The Deadly Mineral? What is Asbestos? What is Asbestos? Uses of Asbestos.

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1 GEOL 100 (Planet Earth) Topic #6 - Asbestos: The Deadly Mineral? What is Asbestos? Group of highly fibrous silicate minerals that are flexible, strong, heat resistant. Three common varieties: 1) White Asbestos = Chrysotile (sheet silicate, ~95% of asbestos) By Stephen Altaner (Univ. of Illinois) What is Asbestos? 1) White Asbestos Three common varieties: 2, 3) Blue and Brown Asbestos = Amphibole (double chain silicate) (~5% of asbestos) Brown Asbestos Insulation, tiles, shingles, brake linings, cement construction, ceiling plaster, asphalt Blue Asbestos Theater curtains 1

2 Protective clothing Fake snow in home/movies Wizard of Oz Christmas decoration Holiday Inn White Christmas Asbestos is potential health hazard if fibers become airborne, enter lungs, become lodged If fiber-loading in lungs is very large, its performance (exchange of O2 and CO2) declines. General disease is pneumoconiosis ("dust in lungs") characterized by fibrosis, involves hardening of lungs due to buildup of excess collagen from very large number of lodged mineral particles (cause of death is usually heart failure not suffocation) Dust storm Types of Pneumoconiosis Asbestosis = asbestos buildup Silicosis = silica dust buildup Black Lung Disease = coal dust buildup Other diseases from inhaled asbestos Lung cancer = silica dust buildup Mesothelioma = rare (usually fatal) lung cancer associated with inhaling blue asbestos Coal Dust 2

3 Essentials of Geology, 4 th edition Ongoing debate about long-term health effects of asbestos Some scientists/health workers think it is major health hazard including general public Others think asbestos in general environment poses little health hazard 1) Heavy exposure to airborne white asbestos over long time (decades) can cause asbestosis - In early 1900s asbestos miners and workers found to contract asbestosis from very heavy exposure to asbestos (>100,000 asbestos fibers per breath) over many years + no precautions Johns-Manville Asbestos Plant, Manville, NJ Early asbestos mine 1) Regulations (wet asbestos during breaking, breathing masks) have ~eliminated asbestosis in US, but unregulated asbestos work settings around world, e.g., China Improper asbestos handling (below and right) 2) Heavy exposure to airborne white asbestos slightly increase risk of lung cancer (if you smoke cigarettes) - In 1950s and 1960s, high-level exposure to asbestos for decades also causes lung cancer (at slightly higher levels than general public) to people who are also smokers Proper asbestos disposal Airborne white asbestos 2) Residents of Thetford, Canada (world's largest open pit mine for asbestos) do not show high levels of asbestosrelated diseases. 3) Low exposure to airborne amphibole (blue) asbestos can cause mesothelioma - Based on lab experiments on animals + studies of asbestos miners Thetford open pit asbestos mine Blue asbestos 3

4 3) Curly white asbestos doesn t penetrate as far into lungs as rod-like amphibole asbestos; white asbestos easily dissolved in lung (weeks to months), but amphibole asbestos remains in lungs for long time (decades or more) 4) Friable (easily crumbled) asbestos (used as spray coating for fireproofing + soundproofing; banned in US since 1970's) becomes airborne easily, but other forms (in floor tile or roof shingle) don t emit airborne fibers unless sawed or sanded Non-friable asbestos around hot water pipes (above), in vinyl tile (below) Large curly white asbestos fibers (hand sample-above, microscope view- right) Small straight amphibole asbestos fibers (microscope view) Friable asbestos in spray on form for fireproofing (controversial) - Need to determine level + type of airborne asbestos in general living environment (usually very low levels of white asbestos) + toxicity of those levels. 4

5 (controversial) - Opposing view emphasizes studies of asbestos workers who have experienced health effects and difficulty in determining long-term health effects EPA Regulations on Asbestos In 1978, use of spray-on asbestos banned in US In 1986 all schools must be inspected for asbestos Mentality of "1 asbestos fiber can kill" produced many lawsuits, destroyed asbestos industry in USA USA spends $1-4 billion per year on asbestos removal EPA Recommendations on Asbestos Expensive High levels of airborne asbestos months after removal Possible poor removal methods Problems with Asbestos Removal Remove asbestos only when it is severely damaged and beyond repair Otherwise, contain asbestos in place (repair, if necessary), = asbestos management program Problems with Asbestos Removal Damaged asbestos around pipes (above) and ductwork (right) Spray on asbestos for fireproofing Expensive High levels of airborne asbestos months after removal Possible poor removal methods Replacement materials (fiberglass) have unknown health effects (possibly much worse than asbestos) 5

6 Essentials of Geology, 4 th edition Health Effects of Inhaled Quartz High levels of inhaled quartz cause silicosis (well-known) Questionable health studies concluded that inhaled quartz can cause lung cancer All materials with > 0.1 % quartz must label product as containing "probable human carcinogens" Towns must monitor airborne dust levels, consider steps to reduce dust levels, if too high Freshly broken, fine-grained quartz probably is hazardous, other forms probably aren t, proposed regulations for all quartz 6