Asbestos

• It is a known carcinogen
• It was widely used in the US in various products, such as building materials
• Still currently in use in some products in US (roofing, gaskets, friction parts)
• Ongoing asbestos abatement in buildings
• Current litigation issue
• The California State rock (serpentine)

• TERRESTIRAL FATE:

  Movement of asbestos fibers only occur during runoff or erosion. Asbestos fibers will not volatilize or degrade although they may be re-suspended to the air by vehicular traffic over unpaved soil surfaces containing asbestos or through mining and milling operations

• AQUATIC FATE:

  Asbestos will degrade in water.

• ATMOSPHERIC FATE:

  Asbestos released to the air will eventually settle out by gravitational settling and dry deposition. In US cities, average concentration of 2-4 ng/cu m

• Due to some of its physical and chemical properties, asbestos has been mined, milled, and used in thousands of products in the US and abroad
• Egyptian burial cloths & Charlemaigne's table cloth
• US Regulations starting in 1970?s

• Asbestosis (fibrous scarring of the lung)
• Lung cancer
• Mesothelioma (Very rare, and primarily associated with asbestos exposure)
• Gastrointestinal cancer
• Significant elevation in the incidence of cancers of the larynx, pharynx and buccal cavity, and kidney

• Forms long thin fibers
• Tensile strength (matrix re-enforcement)
• Thermal & electrical insulation
• Sound insulation
• Non-flammable
• Adsorption capacity
• Wear & friction properties

• Serpentine (Chrysotile)

  
  It has a layered structure made up of SiO4 tetrahedral and Mg(OH)2 layers. The mismatch between those two types of layers is responsible for a curvature in the structure cylindrical/tubular form of the chrysotile fibres. The connections between the layers are weak, giving the chrysotile asbestos
  • Comprises majority of asbestos used commercially
  • Can be woven into fabrics

• Amphiboles

  
  The amphibole structure is formed by double Si and O chains. The chains are connected by other elements like Na, Mg, Ca en Fe. Amphibole fibres have a diamond-shaped cross-section. They are less flexible than serpentine fibres, and they tend to split into small, very sharp splinters.
  • Primarily used for thermal systems insulation (pipe lagging, etc.).

• Respiratory route is the most important
• Gastrointestinal and dermal routes less significant
• The majority of inhaled asbestos is either exhaled or becomes lodged in phlegm and is then excreted through the GI tract.
• Once an asbestos fiber reaches the alveoli, it can become lodged in the lung for years.
• Some asbestos fibers can become dislodged from the alveolar wall, and be transported elsewhere
• Fibers can accumulate in the lung, and cause inflammation and scarring affects breathing, leading to disease = Asbestosis (10-30 year latency period)
• Lung Cancer (15-20 year latency period)
• Mesothelioma of the plura of the lungs or the peritoneum of the abdomen (20-40 year latency)
• Amphiboles remain in lung longer, and may therefore be more harmful

• Fibers retained in the lung are <3- 200 um
• A portion of the fibers become coated with an iron protein complex
• All types of asbestos cause microphage-mediated fibrosis. The areas increase in size and coalesce causing diffuse fibrosis with shrinkage.
• The process starts in the bases spreading upwards as the disease progresses; in advanced disease the whole lung structure is distorted and replaced by dense fibrosis, cysts, and some areas of emphysema.

• Lung Cancer
• Mesothelioma

• Reactive Oxygen Species (Inflammation & macrophages)
  • Size
  • Shape
  • Chrystallinity
  • Solubility
  • Distance between DNA & sources of ROS
• Oxide-reduction processes
  • Iron reactivity
  • Phagocytosis
• Altered Gene Expression
  • Cell proliferation
    • Cell proliferation

• In-vivo chromosomal aberrations
• Impaired mitosis
  • chromosome missegregation
  • spindle changes
  • alteration of cell cycle progression
  • aneuploid and polyploid cells
  • nuclear disruption

• Asbestos abatement workers
• Plumbers
• Electricians
• Construction workers/demo crews
• Miners (not US)
• Automobile repairers

• Families of occupationally exposed workers
• Persons living near asbestos mines
• Persons living in areas with asbestos-rich soils
• Persons occupying building with asbestos-containing materials (ACM) in poor conditions , or ACM being disturbed
• Persons located near such buildings

• Exposure: concentration what was the concentration of asbestos fibers?
• Exposure: duration how long did the exposure time period last?
• Exposure: frequency how often during that time period was the person exposed?
• Size, shape and chemical makeup of asbestos fibers
• Smoking!
  • Estimates of 50% to 90x increased cancer risk (Synergetic)
  • If a smoker has an asbestos exposure history, they can reduce their risk of developing an asbestos-related respiratory disease if they stop smoking.

• Not all ACBM must be removed
• The removal of ACBM is regulated and includes:
  • Use of PPE
  • Preparation of work site
  • Construction of Containment & decontamination chambers
  • Work to be performed under the supervision of a competent person
  • Removal to be performed using wet methods
  • Debris to be bagged and disposed of appropriately
  • No visible emissions
  • Post-cleaning
  • Personnel Monitoring
  • Clearance sampling must or should be conducted
  • Post-removal strike-down, lockdown and application of substitutes

• Safety/rubber boots
• Disposable protective clothing
• Head covering
• Leather gloves
• Hard hats
• Eye protection
• Respirator
  • 1/2 face
  • Full-face
  • PAPR
  • Supplied Air

• Personnel records
• Sign-in sheets
• Lock-out/tag-out
• Pre-clean the room
• Remove contents from room and/or cover

Containment:

• Cover windows, doors, HVAC supplies and intakes, floor.
• Use 6-mil polyvinyl sheeting to construct containment

Decontamination Chambers Establish Area Post Signage

• EPA
  • Asbestos Hazard Emergency Response Act under TSCA (AHERA, 40 CFR 763)
  • Asbestos School Hazard Abatement Reauthorization Act under TSCA (ASHERA)
  • National Emission Standards for Hazardous Air Pollutants under Clean Air Act (NESHAP, 40 CFR 61 part M)
  • Clean Water Act (EPA 7 mf/l [million fibers/l])
• OHSA
  • Construction Industry (29CFR 1926.1101)
  • General Industry (29 CFR 1910.1001)
  • Shipyard Workers (29 CFR 1915.1001)

• Subpart E-Asbestos-Containing Materials in Schools
  • Appendix A to Subpart E-Interim Transmission Electron Microscopy Analytical Methods-Mandatory and Nonmandatory-and Mandatory Section to Determine Completion of Response Actions
  • Appendix C-Asbestos Model Accreditation Plan
  • Appendix D-Transport and Disposal of Asbestos Waste
  • Appendix E-Interim Method of the Determination of Asbestos In Bulk Insulation Samples
• Subpart G-Asbestos Worker Protection
• Subpart I (TSCA Ban)-Prohibition of the Manufacture, Importation, Processing, and Distribution in Commerce of Certain Asbestos-Containing Products; Labeling Requirements
  • 1989 EPA announced ban and phase-down rule over 7 years to begin 1990.
  • Use of asbestos products would have been banned in US, except products w/o substitutes and military use.
  • 1991 Louisiana 5th Circuit Court of Appeals vacated regulation. Only 6 product categories subject to Ban & Phase-out rule:

    • Result of TSCA Appeal Finding

      • Products still subject to ban:
        • Corrugated paper
        • Roll board
        • Commercial paper
        • Specialty paper
        • Floor felt
        • New uses
      • Products not subject to ban:
        • asbestos-cement corrugated sheet, asbestos-cement flat sheet, asbestos clothing, pipeline wrap,
        • roofing felt, vinyl-asbestos floor tile, asbestos-cement shingle, millboard, asbestos-cement pipe,
        • automatic transmission components, clutch facings, friction materials, disc brake pads, drum
        • brake linings, brake blocks, gaskets, non-roofing coatings, and roof coatings

• Model Accreditation Plan
• Extends AHERA requirements to public and commercial buildings

• Protects the public by minimizing the release of asbestos fibers during activities involving the processing, handling, and disposal of ACM
• Notification requirements
• Work practices standard
• Zero visible emissions to outside air
• NESHAP Regs apply to removal of 260 LF or 160 SF of Regulated ACM
• Locally, NESHAP is enforced by S. Cal. Air Quality Management District.

NESHAP Product Bans

• Most spray-applied surfacing materials containing >1% asbestos (unless encapsulated, non-friable & no emissions)
  • Fireproofing
  • Decorative
• Thermal System Insulation
  • Pipe insulation
  • Insulation for boilers

• Permissible Exposure Limit: 0.1 fibers/cc
• 30 min Excursion Limit: 1 fiber/cc

• Worker Protection
  • Medical Surveillance
  • Respiratory protection
  • Work practices & engineering controls
  • Personnel exposure monitoring
  • Smoking cessation
• Bulk sample analysis

• Worker Protection
  • Medical Surveillance
  • Respiratory protection
  • Work practices and engineering controls
  • Personnel exposure monitoring
  • Smoking cessation
• Bulk sample analysis

• Applies to:
  • Demolition
  • Renovation
  • Maintenance/repair
  • Emergency clean-up
  • Transportation/disposal
• Does not apply to asphalt roof coatings, cement and mastics.
• Work area protection
• Worker protection
• Exposure assessments
  • Negative Exposure assessments
• Engineering controls
• Work practices/housekeeping

• Cal/OSHA
  • Construction Industry (CCR,Title 8, Section 1529)
  • General Industry (Section 5208 of General Industry Safety Orders).
• Cal/EPA
  • Department of Toxic Substance Control

• local fire department
• County and city Ordinance

• http://www.epa.gov/asbestos/
• http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9995
• http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10862
• http://www.osha.gov/SLTC/asbestos/
• http://www.osha.gov/SLTC/constructionasbestos/
• http://www.atsdr.cdc.gov/asbestos/
• http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~6EIoyw:1
• http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~5JKyOO:1
• http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~s0N5o1:1
• Roach, H. D, et al, "Asbestos: When the Dust Settles-An Imaging Review of Asbestos-related Disease," Radiographics 2002;22:S167-S184.
• Schins, R. D, "Mechanisms of Genotoxicity of Particles and Fibers," Inhalation Toxicology 2002; 14(1):57-78
• Jaurand, M. C, "Mechanisms of Fiber-Induced Genotoxicity," Environmental Health Perspectives 1997;105:S5:1073-1084
• Barrett, J. C, Shelby, M. D, "Mechanisms of Human Carcinogens," Progress in Clinical and Biological Research 1992; 374:415-434.
• McCrone, W. C, Asbestos Identification, G&G Printers, 1988
• NATEC Inernational, Inc., Asbestos Contractor Supervisor Refresher Course.
• California Code of Regulations, Title 8, Section 1529
• California Code of Regulations, Title 8, Section 5208