Tarred leaky skylight (C) Daniel Friedman Asbestos Sources in Mastics, Cutback Adhesive, Underlayments, or Roofing Sealants

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Sources of asbestos found in adhesives, mastics, or sealants used in flooring or roofing: this article lists common sources of asbestos that may be encountered when demolishing or renovating older floors, floor underlayment, or roofs and roofing underlayment.

This article series answers questions about floor tile, sheet flooring, or roofing cutback adhesives or mastics that may contain asbestos.Does or did roofing mastic products & sealants contain asbestos? What are the hazards of demolishing or working on floors or roofs where asphalt-based asbestos-containing mastics, cutback adhesives, or sealants were used? Page top photo of black mastic floor tile adhesive provided courtesy of reader G.M.

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Sources of Asbestos in Flooring Adhesives & Underlayment

Asbestos containing vinyl asbestos floor tilesList of Authoritative sources reporting the use of [or absence of] asbestos in any form of flooring underlayment, cutback adhesive, floor tile mastic, roofing mastic, roofing sealant or roof flashing cement

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  • Asbestos in tile mastics & roofing mastics or adhesives: some tile mastics and adhesives including adhesives used for floor or wall tiles did contain asbestos as a filler or fiber strengthener.
  • Cement asbestos slates were described in the Journal of Hazardous Materials as [safely] recyclable in production of stoneware tile mixtures in 2008 [27] and a procedure for producing [safe] lightweight ceramic materials by a process bonding chrysotile asbestos fibers was described by Mackenzie and Meinhold in 1994. [28]

    Other roofing products contain asbestos.
    See ASBESTOS CEMENT PRODUCTS for examples.
  • Ceramic tile asbestos sources: Unlike asphalt-asbestos floor tiles or sheet flooring and later vinyl-asbestos floor tiles or sheet flooring, traditional ceramic tile installations were bedded in cement, not mastic, and not an asbestos containing material. But from the 1960's some ceramic tile installations used a thin-set mortar or a thin-set mastic that might contain asbestos as was the case with the other floor coverings we just named.
  • ACM flooring underlayment [underlayment is not ceramic tile itself ] has been found under flooring in demolition projects, a practice that can extend to ceramic floor tiles [4]
  • Asbestos in roofing underlayment: some older asphalt-impregnated felts contained asbestos
  • Asbetic flooring: using asbestos mine waste products (largely dust and very short asbestos fibers) is described by Rosato [23]. The result was a "hard but not completely water tight" flooring material. Asbetic is a mixture of ground mother rock and the shortest, otherwise unusable asbestos fibers. [He does not name ceramic tile flooring in this category.]
  • Asbestos in tile mortar: Asbestos used as an ingredient in tile mortar is described in a patent dispute.[27]
  • Survey of Accredited Laboratories for Asbestos Fiber Analysis [42]

Possible sources of confusion about asbestos content in ceramic floor tiles:

  • Asbestos in clay products: Asbestos has been reported in art clay (such as Fibro-Clay)[37] used in schools and in pottery clay where it occurred in the form of talc added as a flux to lower the firing temperature. Talc and clay from at least one U.S. mine contained anthophyllite asbestos. It was unclear whether or not this material fell under the aegis of asbestos regulation.[36] The asbestos content of talc depended on where it was mined, and some talcs were asbestos-free[40].

    Depending on the quarry source there may be deliberate or accidental inclusion of asbestos in terra cotta tiles such as roofing tiles. Other clay products that may have had asbestos added in the form of talc or vermiculite (some vermiculite contains asbestos) in addition to art clays, may include clays used as pipe joint seals or insulation, and in the production of firebricks used to line the combustion chambers of heating equipment such as boilers or furnaces, and other school art projects such as paper marches.[38][39]
  • Pre-historic origins of use of asbestos in clay pottery: The use asbestos-strengthened ceramic wares (pottery) dates from the Stone Age and continued throughout the Bronze Age and into the Iron Age. Specifically, asbestos fibers were used to strengthen earthenware pots and cooking utensils as long s 4,500 years ago, an application documented by various sources.[26] Also, a Wikipedia entry on Asbestos-ceramic describes pottery made with asbestos and clay [25].
  • Asbestos textiles were used as safety protective clothing & gear for workers in the ceramics industries - a possible source of confusion associating the terms "ceramic tile" and "asbestos" in some search engine results. Some mesothelioma information and legal resource websites name "ceramic tiles" as containing asbestos [22] without citing an authoritative source.
  • ASBESTOS List of Asbestos-Containing Products - the InspectAPedia master list of asbestos forms and asbestos-containing products, enumerates asbestos-containing-materials (ACM) using historical information derived from Rosato and other industry sources.

    Rosato who provided an extensive discussion of asbestos used in flooring materials, referred exclusively to the use of asbestos in resilient flooring products (such as vinyl asbestos floor tiles) and excluded non-resilient flooring (stone, slate, ceramic tile).

    Rosato confirms use of asbestos and clay as mixture ingredients in premix-molding-compounds and the use of asbestos fibers mixed with ceramic fibers to form filter paper for the paper making industry (these are not ceramic tile products) [23]
  • Asbestos ceramic bricks: Leonelli et als. refer to the disposition of asbestos by microwave treatment of asbestos waste into ceramic bricks - another possible source of association of the words "ceramic" and "asbestos" in web searches that does not extend to ceramic tiles. National Center for Biotechnology Information, NIH, USA[24]


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