Why is Asbestos Significant?
  • It is a known carcinogen
  • It was widely used in the US in various products, such as building materials
  • Ongoing asbestos abatement in buildings
  • Current litigation issue
  • The California State rock (serpentine)
Fate and Transport
    Movement of asbestos fibers only occurs 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.
    Asbestos will degrade in water.
    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.
Historical Significance
  • 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
Where Can Asbestos be Found?
  • Cement Pipes
  • Laboratory Hoods/Table Tops
  • Elevator Brake Shoes
  • Cement Wallboard
  • Laboratory Gloves
  • HVAC Duct Insulation
  • Cement Siding
  • Fire Blankets
  • Boiler Insulation
  • Asphalt
  • Floor Tile
  • Pipe Insulation (corrugated air-cell, block, etc.)
  • Fire Curtains
  • Vinyl Floor Tile
  • Elevator Equipment Panels
  • Flexible Fabric
  • Vinyl Sheet Flooring
  • Caulking/Putties
  • Cooling Towers
  • Flooring Backing Adhesives
  • Pipe Insulation
  • Construction Mastics (floortile, carpet, ceiling tile, etc.)
  • Wallboard Heating and Electrical Ducts
  • Acoustical Plaster Joint Compounds
  • Vinyl Wall Coverings
  • Decorative Plaster Spackling Compounds
  • High Temperature Gaskets
  • Textured Paints/Coatings
  • Roofing Shingles Roofing Felt
  • Ceiling Tiles
  • Thermal Paper Products
  • Spray-Applied Insulation
  • Fire Doors
  • Electrical Cloth
  • Blown-in Insulation
  • Electrical Panel Partitions
  • Fireproofing Materials
  • Taping Compounds
  • Electric Wiring Insulation
  • Chalkboards
Adverse Health Effects
  • Asbestosis (fibrous scarring of the lung)
  • Lung cancer
  • Mesothelioma (Very rare, and primarily associated with asbestos exposure)
  • Gastrointestinal cancer
  • A Significant elevation in the incidence of cancers of the larynx, pharynx and buccal cavity, and kidney
Physical and Chemical Characteristics
  • Forms long thin fibers
  • Tensile strength (matrix re-enforcement)
  • Thermal & electrical insulation
  • Sound insulation
  • Non-flammable
  • Adsorption capacity
  • Wear & friction properties


Asbestos Chemical Structure
  • Asbestos is a mineral composed primarily of silica, magnesium and water.
  • Asbestos is classified as serpentines and amphiboles.
Types of Asbestos
  • Serpentine (Chrysotile)

    AsbestosIt 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


    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.).


Toxicology of Asbestos
  • Respiratory route is the most important
  • Gastrointestinal and dermal routes less significant
  • 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
Pathology of Asbestosis
  • 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.


Toxicology of Asbestos as a Carcinogen

Toxicology of Asbestos as a Carcinogen

  • Lung Cancer
  • Mesothelioma
Asbestos Mutagenicity
  • 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
Demonstration of Genotoxicity
  • In-vivo chromosomal aberrations
  • Impaired mitosis
    • chromosome missegregation
    • spindle changes
    • alteration of cell cycle progression
    • aneuploid and polyploid cells
    • nuclear disruption
Asbestos-Related Lung Cancer


Mesothelioma development over time



"Historical" Target Occupations
  • Asbestos textile mill workers
  • Automobile workers and repairers
  • Building material manufacturers
  • Cement plant production workers
  • Construction workers (including insulators, boilermakers, laborers, steel/ironworkers, plumbers, steam fitters, plasterers, drywallers, cement and masonry workers, roofers, tile/linoleum installers, carpenters, HVAC mechanics and welders)
  • Electrical workers, including electricians, electrical linemen, and telephone linemen
  • Miners
  • Shipyard workers (including electricians, insulators, laborers, laggers, painters, pipefitters, maintenance workers, and welders)
  • Custodians, insulation manufacturing plant workers, insulators, machinists, packing and gasket manufacturing plant workers, pipefitters, and powerhouse workers
  • Railroad workers, steamfitters, refinery workers, sheetmetal workers, refractory products plant workers, rubber workers
  • Aerospace and missile production workers, aircraft manufacturing production workers, and aircraft mechanics


Current Target Occupations
  • Asbestos abatement workers
  • Plumbers
  • Electricians
  • Construction workers/demo crews
  • Miners (not US)
  • Automobile repairers
Target Populations
  • 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
Additional Risk Factors
  • 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.
Additional Risk Factors
  • 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
Personal Protective Equipment
  • Safety/rubber boots
  • Disposable protective clothing
  • Head covering
  • Leather gloves
  • Hard hats
  • Eye protection
  • Respirator
    • 1/2 face
    • Full-face
    • PAPR
    • Supplied Air
Preparation of Work-Site
  • Personnel records
  • Sign-in sheets
  • Lock-out/tag-out
  • Pre-clean the room
  • Remove contents from room and/or cover


Construction of Containment


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

Decontamination Chambers Establish Area Post Signage

Debris to be bagged wet, and disposed of appropriately


Clearance Criteria
  • ACM removed as necessary
  • No debris/dust
  • Passing air sample results:
    • 0.01 fibers/cc PCM
    • 70 structures/mm2 TEM


Replacement Agents

Product Type

  • fabrics/papers
  • Asbestos-containing cements/plasters
  • Asbestos-containing break linings or disks

Fabrics/papers uses

  • Insulation
  • Pipe lagging
  • Theater curtains
  • Thermal systems insulation
  • Beer/wine filters

Asbestos-containing cements/plasters uses

  • Stucco
  • Concrete
  • Cement pipes
  • Cement boards

Asbestos-containing break linings or disks uses

  • Breaks
  • Clutches

Replacement: fabrics/papers

  • Fiberglass
  • Synthetic
  • Kevlar
  • Ceramic
  • Cellulose products

Replacement: Asbestos-containing cements/plasters

  • Perlite
  • Ceramic fiber
  • Non-asbestos minerals
  • Mineral wool
  • Diatomacious earth & lime

Replacement: Asbestos-containing break linings or disks

  • Synthetics
  • Metallic fiber
  • Glass fiber
Regulations: Federal Regulations
  • 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
OSHA-General Industry
    • Worker Protection
      • Medical Surveillance
      • Respiratory protection
      • Work practices & engineering controls
      • Personnel exposure monitoring
      • Smoking cessation
    • Bulk sample analysis
OSHA-Shipyard Workers
  • Worker Protection
    • Medical Surveillance
    • Respiratory protection
    • Work practices & engineering controls
    • Personnel exposure monitoring
    • Smoking cessation
  • Bulk sample analysis
OSHA-Construction Industry
  • 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
State Regulations
  • 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 Regulations
  • local fire department
  • County and city Ordinance


For over 20 years, Clark Seif Clark’s highly qualified Team has been providing a broad range of hazardous materials and health & safety compliance professional services to resolve complex environmental issues.  The cornerstone of our ability to meet client goals and objectives is our commitment to Value Engineering.  Our staff is highly motivated and successful at providing the most cost-effective approach when conducting environmental surveys; performing hazard assessments; preparing remediation and abatement work plans; and representing our client’s  best interests when providing field oversight of third-party contractors to ensure the quality of their work and conducting negotiations with regulatory authorities.

Contact us to learn how we can identify the best solution to your environmental concerns.