Asbestos Information

Asbestos Sources
The best source of asbestos information and lead regulations in the State of Maine is the Maine Department of Environmental Protection in Augusta, Maine. They can be reached by calling (207) 287-2651. You can also reach them through their website.


Maine DEP Website

Asbestos Information
A. Characteristics

  1. Asbestos is the common name for a group of fibrous, mineral silicates, having unique properties.
  2. These properties include:
        a. Noncombustible
        b. High tensile strength
        c. Good noise absorption
        d. Thermal insulator
        e. Condensation control
        f. Resistant to the effects of corrosive chemicals
        g. Resistant to the effects of friction
  3. The various types of asbestos, their characteristics, and uses are given in Table I.

B. Historical Uses

  1. Asbestos has been used for over two thousand years. The meaning stemmed from the Greek word "quenchable" - derived from the observation that the material would not burn.
  2. Marco Polo reported the use of asbestos in gun powder by the Chinese.
  3. A tablecloth belonging to Charlemagne was woven with asbestos.
  4. In 1729, Benjamin Franklin sold a purse fabricated with asbestos to his British benefactor.

C. Modern Uses

  1. The unique characteristics of asbestos have resulted in a very diverse use of the material over the years. The asbestos industry reports that currently over 3,600 products contain asbestos.
  2. Asbestos-containing products can be divided into two categories:
    • Category I - Friable Material and Asbestos Textile Products
    • Category II - Nonfriable Matrix-Bonded Composite Products
  3. Table II lists categories, product uses, and approximate dates of use

D. Trade Names

  1. Listed in Table III are the types of application and the associated trade names of some asbestos-containing products

E. Methods of Application

  1. Sprayed-On
    • Asbestos was sprayed onto structures in auditoriums, hallways, and classrooms for fireproofing, noise absorption, condensation control, and decorative purposes.
    • Sprayed-on asbestos is usually friable.
    • Two methods were used to spray-apply asbestos:
      1. Wet Method
        • Generally, a mixture might have consisted of a slurry of one or more of the following: asbestos (5-30%), mineral wool, and/or fiberglass, and Portland cement, gypsum, pearlite and vermiculite.
        • This material was more dense and less friable than that applied by the dry method (described below).
        • The thickness of the application usually ranged from 1/2 to 1 inch.
        • Chrysotile was usually used in the formulation.
        • The surfaces were often trowelled after application, resulting in a harder, more dense material.
      2. Dry Method
        • Generally, a mixture consisted of a dry blend of asbestos fibers (5-90%) and one or more of the following: mineral wool or fiberglass, Portland cement or gypsum, water-soluble resins, starches, and other additives.
        • The mixture was applied with a sprayer and wetted as it passed through the nozzle. The water activated the water-soluble resins, producing a wet fiber matrix, which readily adhered to the application surface.
        • The thickness of the application was usually 1/2 to 2 inches.
        • Amosite, chrysotile, or both were often used; Crocidolite was used infrequently.
        • Because of the method, the asbestos content can vary greatly within the same application.

    2. Pipe and Boiler Insulation

    1. a. This insulation is usually applied by pasting preformed blocks or sheets or by applying wetted asbestos-containing compounds.
    2. b. Generally, three types of insulation were used:
      • Preformed sections, blocks or siabs
      • Insulating cement for values, elbows or over fiberglass ducts
      • Asbestos paper products (flat sheets or corrugated).

F. Airborne Asbestos

  1. Unlike many man-made fibers, asbestos as it is mined and used in manufacturing rarely is in single-fiber form. It can continue to split into smaller and smaller fiber bundles.
  2. The average fiber diameter ranges from 0.11 to 0.24 micrometers. However, asbestos can split into even smaller bundles,which cannot be seen with an optical microscope.
  3. These fine fibers settle from the air very slowly. In completely still air, fibers of the size usually found in overhead spray insulation in a occupied 8' or 10' office take approximately 80 hours to settle.


Table I

Scientific Name Characteristics Source
Chrysotile White asbestos; fine silky fibers; flexible and high tensile strength; accounts for over 90% of the uses of asbestos. Canada
Soviet Union
Amosite Brown asbestos; brittle fibers; bonds well with plastics and is used in heat insulation materials. South Africa
Crocidolite Blue asbestos; strongest of the asbestos fibers; brittle fibers; usually found in combination with chrysotile in pipes and sheeting; also occasionally found with amosite or chrysotile in pipe and boiler wrap; also used as decorative material. South Africa
These three are types of asbestos most often found in construction materials and commercial products. Tremolite, actinolite, and anthophyllite are also asbestos minerals, but rarely found in building and commercial products.


Table II

Scientific Name Characteristics Source Source Source
Surfacing Material sprayed-on or troweled-on 1-95 1935-1970 Sodium silicate, portland cement, organic biners.
Preformed thermal insulating products batts blocks and pipe covering
85% magnesia
15 1926-1949 magnesium carbonate
Textiles cloth
blankets (fire)
100 1910-present none
  felts 90-95 1920-present cotton wool
  felts: blue stripe 80 1920-present cotton
  felts: red stripe 90 1920-present cotton
  felts: green stripe 95 1920-present cotton
  sheets 50-95 1920-present cotton wool
  cord/rope/yarn 80-100 1920-present cotton wool
  tubing 80-85 1920-present cotton wool
  tape/strip 90 1920-present cotton wool
  curtains: theatre/welding 60-65 1945-present cotton
Cementitious: concrete-like products extrusion panels 8 1965-1977 portland cement
  corrugated 20-45 1930-present portland cement
  flat 40-50 1930-present portland cement
  flexible 30-50 1930-present portland cement
  flexible perforated 30-50 1930-present portland cement
  laminated 35-50 1930-present portland cement
  roof tiles 20-30 1930-present portland cement
  clapboard 12-15 1944-1945 portland cement
  siding shingles 12-14 unknown-present portland cement
  roofing shingles 20-32 unknown-present portland cement
  pipe 20-15 1935-present portland cement
Paper Products corrugated: high temp. 90 1935-present sodium silicate
  corrugated: moderate temp. 35-70 1910-present starch
  indented 98 1935-present cotton and organic binder
  millboard 80-85 1925-present starch, lime, clay
Roofing felts smooth surface 10-15 1910-present asphalt
  mineral surface 10-15 1910-present asphalt
  shingles 1 1971-1974 asphalt
  pipeline 10 1920-present asphalt
Asbestos containing compounds caulking putties 30 1930-present linseed oil
  adhesive (cold applied) 5-25 1945-present asphalt
  joint compound   1945-1975 asphalt
  roofing asphalt 5 unknown-present asphalt
  mastics 5-25 1920-present asphalt
  asphalt tile cement 13-25 1959-present asphalt
  roof putty 10-25 unknown-present asphalt
  plaster/stucco 2-10 unknown-present portland cement
  spackles 3-5 1930-1975 starch, casein, synthetic resins
  sealanis fire water 50-55 1935-present caster oil or polyisobutylene
  cement, insulation 20-100 1900-1973 clay
  cement, finishing 55 1920-1973 clay
  cement magnesia 15 1926-1950 magnesium carbonate
Flooring tile and Sheet Goods vinyl asbestos tile 21 1950-present poly(vinyl)chloride
  asphalt asbestos tile 26-33 1920-present asphalt
  sheet good/resilient 30 1950-present dry oils
Wallcovering vinyl wallpaper 6-8 unknown-1973  
Paints and Coatings roof coating 4-7 1900-present asphalt
  air tight 15 1940-present asphalt


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