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Increasing Awareness: Asbestos. Ancient History, Characteristics, Types, Uses, Health Effects. Asbestos Definition. The word asbestos derives from a Greek word meaning “inextinguishable”. Asbestos definition.
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Increasing Awareness: Asbestos Ancient History, Characteristics, Types, Uses, Health Effects
Asbestos Definition • The word asbestos derives from a Greek word meaning “inextinguishable”
Asbestos definition • Either of two incombustible, chemical-resistant, fibrous mineral forms of impure magnesium silicate, used for fireproofing, electrical insulation, building materials, brake linings, and chemical filters.
What is Asbestos? • Natural Mineral (Rock)
Brief History • First known use: 2,500 B.C. pottery and hut insulation • Greeks spun and used in cloth • Used for wicks in sacred lamps • Pottery • Diseases in the 1950s-1960s • 1971 Asbestos listed as a hazardous air pollutant
Characteristics • Aerodynamic • Aerodynamic
Characteristics • Aerodynamic • Chemically Resistant • Hydrophobic • Heat resistive (1250-2000 deg. F) • Flexible with High Tensile Strength • Aerodynamic • Chemically Resistant • Hydrophobic • Heat resistive (1250-2000 deg. F) • Flexible with High Tensile Strength
Characteristics continued • Size • Fibers (1-5 microns, human hair is 80) • Fibers>Fibrils>microfibrils
Asbestos Types • Chrysotile (white) • >95% of all asbestos (white) • Hair-like
Asbestos Types • Amosite (Brown) • 5 % of all asbestos • Needle Like
Asbestos Types • Crocidolite (blue) <1 %
Asbestos Types • Chrysotile >95% of all asbestos (white) • Amosite <5% of all asbestos (brown) • Crocidolite (blue) <1 • Tremolite • Anthophyllite • Actinolite
Asbestos Types • Tremolite, Anthophyllite, Actinolite • Little commercial value • Usually a contaminant of other asbestos or material type
Why Use Asbestos? • Heat resistive (1250-2000 deg. F) • Chemically resistive • Great acoustical reduction properties • Good elastic/tensile strength properties • Poor conductor of electricity • Great binder
Asbestos Containing Materials • Acoustical Materials • Fire proofing • Heat resistive materials • Ceiling and floor tile • Sheet rock mud • Plaster • Insulation
Materials cont. • Decorative spray for texture • Roof shingles, siding shingles, sheets, etc. • Mastics, glues • Welding booth panels and soffits • Window glazing • Some paints
Health Effects • Caused by • Inhalation (most likely) • Ingestion • Injection
Asbestos Diseases • Asbestosis (lung scarring) • Lung cancer • Mesothelioma (cancer of membrane lining lungs) • Pleural plaques, pleural thickening • Colon, stomach, esophagus, pancreas cancers
Respiratory Systems Defense Mechanisms • Nose, Mouth, • Trachea, Bronchus, Bronchioles • Turbulent airflow • Smaller pathways • Mucous • Sticky layer, catches some particles
Respiratory Systems Defense Mechanisms (Continued) • Cilia • Hair-like • Coated with mucous and move particles back up through bronchus • Alveoli (air sacs) • O2/CO2 exchange • Macrophage Cells
Asbestos-Smoking-Lung Cancer • Asbestos exposure=5X greater chance lung cancer • Smoking no asbestos exposure=10X greater chance lung cancer • Asbestos exposure of Smoker=50X greater chance of lung cancer. Newest figures now say 88X greater chance
“King of Cool” - Steve McQueen • Died of Mesothelioma in 1980 at the Age of 50 • Exposed to Asbestos from Work/Hobbies • Brake Pads on Cars • Construction Work • Ship Work
What Level of Exposure is Safe or Permissible???????? • 0.1 fibers per cc of air • 5 f/cc, 1 f/cc, 0.1 f/cc in last 10 years
Crowds gather at Market and Laguna streets to flee the Great Fire. Building at lower center right still survives along Laguna. Almost all others pictured here burned.
The 1906 San Francisco Great Fire as seen from a ferry boat in the Bay.
Closing Thought. Keep Health Effects in Perspective • Expected deaths per 100,000 • Motor vehicle 1,600 • Coal mining 441 • Diagnostic X rays 75 • Lightning 3 • Hurricanes 3 • Asbestos in buildings 1
Acknowledgement • Created by Larry Hagel, Industrial Hygienist, Kyron Environmental Consulting and Training • Formerly with Spokane Public Schools and a member of AASA’s Urban Healthy Schools Coalition • Email lhagel@kyronenvironmental.com • AASA is dedicated to healthy school environments, visit http://www.aasa.org/focus/