Source And Identification Of Respirable Fibers

Our plain-English summary of Source And Identification Of Respirable Fibers, by L.J. Cralley, R.G. Keenan, J.R. Lynch, et al (1968).

The study

• Authors: L.J. Cralley, R.G. Keenan, J.R. Lynch, W.S. Lainhart
• Published: American Industrial Hygiene Association Journal 29(2):129-135, March-April (1968)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 003293. The article is still under copyright, so we describe it here rather than post it.

In plain English

This 1968 article was mainly a review and commentary, combined with what the authors called a limited survey of fibrous materials examined under the electron microscope. It discussed earlier reports by other investigators that coated fibrous bodies had been found in the lungs of people autopsied in urban hospitals. The authors noted that these coated fibers had been called "asbestos bodies" even though the fibers inside them were never identified. They described newer laboratory methods for identifying very fine fibers. They also listed minerals with a fiber-like structure, including chrysotile, amosite, crocidolite and tremolite, and stated that there are well over a hundred natural minerals with some fibrous structure. Their electron micrographs showed fibrous material in chrysotile, attapulgite, diatomaceous earth, sillimanite, glass fiber and many everyday products. These included scouring cleaners, insecticide dusts, fertilizer, vermiculite, plaster of Paris, cosmetic talcum powder, toothpaste and an anti-diarrheal medicine. Fibers also appeared in Cincinnati rainwater after a dust storm. The authors concluded that respirable fibers are everywhere. They said more must be learned about the fibers' identity, source and biological effects.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review and commentary, with a limited electron-microscope survey of fibrous materials from products and the environment
• Who was studied: No people were studied. The authors examined samples of fibrous materials from industrial, commercial and household products, and from Cincinnati rainwater. They also discussed earlier autopsy studies by other investigators.
• Exposure: Respirable fibers of mineral, vegetable, animal and synthetic origin. Examples photographed included chrysotile, attapulgite, diatomaceous earth, sillimanite, glass fiber and fibers in household and consumer products.
• Main results:
  • The authors stated that there are well over a hundred natural minerals with some degree of fibrous structure. Their table of examples includes amphiboles such as tremolite, amosite and crocidolite, and serpentine (chrysotile).
  • The table of minerals with fibrous-like structure listed amosite, riebeckite, grunerite and actinolite among the amphibole group.
  • Fibrous materials were shown in home products: scouring cleaners, animal and plant insecticide dusts, yard fertilizers, vermiculite and plaster of Paris.
  • Fibrous materials were also shown in vacuum sweepings from a synthetic carpet, lawn sweepings after mowing, cosmetic talcum powder, toothpaste and a non-prescription anti-diarrheal compound.
  • Fibrous materials were found in rainwater collected in Cincinnati after a dust storm that began in the Texas panhandle-Oklahoma area.
  • The authors stated that the differences in fiber shape seen in the electron micrographs would not be visible at the lower magnification of an ordinary optical microscope.
  • The authors noted that in earlier autopsy studies by others, coated fibers resembling those in asbestos workers were called "asbestos bodies" although the fibers were never identified.
• The authors' conclusion: The authors concluded that respirable fibers are ubiquitous. They said definitive information on the fibers' identification, source and biological response is needed before the meaning of their presence in the lung can be assessed.
• Limitations the authors state:
  • The authors described their survey of fibrous materials as limited.
  • The authors stated that the nature of the fibers from which the coated bodies in the autopsy studies were derived has not been established.

Topics

Medical terms in this study, explained in our Lexicon: Respirable Fiber, Asbestos Bodies, Chrysotile, Amosite, Crocidolite, Tremolite, Palygorskite (Attapulgite), vermiculite.

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