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, chemicalresistant, 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 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
Vermiculite?
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 Sticky layer, catches some particles
Mucous
Respiratory Systems Defense Mechanisms (Continued)
Cilia
Hair-like Coated with mucous and move particles back up through bronchus
O2/CO2 exchange Macrophage Cells
Alveoli (air sacs)
Macrophage Cell
Smoking/Asbestos Relationship
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
Asbestos Health Benefits
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
1,600 441 75 3 3 1
Motor vehicle Coal mining Diagnostic X rays Lightning Hurricanes Asbestos in buildings
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/