Evaluation of asbestos exposure in the working environment. Recommendation of subcommittee on asbestosis of the permanent commission and international association on occupational health

Our plain-English summary of Evaluation of asbestos exposure in the working environment. Recommendation of subcommittee on asbestosis of the permanent commission and international association on occupational health (Journal of Occupational Medicine., 1972).

The study

• Journal: Journal of Occupational Medicine.
• Published: 1972;14(7):560-2
• Read it: PubMed
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001328).

In plain English

This article was not a study but a set of recommendations from the Subcommittee on Asbestosis of the Permanent Commission and International Association on Occupational Health on collecting, counting and describing respirable asbestos fibers in workplaces. The aim was uniform methods so that countries' data could be compared. Air samples were to be collected by the membrane filter technique at the worker's breathing zone for health studies and compliance checks. A fiber was defined as a particle at least 3 times longer than it is wide. Counts were to cover fibers longer than 5 microns, excluding those wider than 5 microns as mostly nonrespirable, using phase contrast microscopy. Because the biological importance of very small fibers was largely unknown, researchers were also asked to use electron microscopy. The subcommittee recommended identifying the fiber type, such as chrysotile, amosite or crocidolite. It also recommended measuring free silica where airborne levels might approach silica standards and, for research, measuring metals and organic contaminants. Countries using other methods, such as the konimeter, were urged to use the recommended procedures alongside them to provide comparative data.

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: Expert committee recommendation on measurement methods (not a study of people or animals)
• Who was studied: No study population; the recommendations concern airborne respirable asbestos fibers in the working environment
• Exposure: Respirable airborne asbestos fibers; the fiber types named are chrysotile, amosite and crocidolite
• Main results:
  • The subcommittee recommended the membrane filter technique for collecting airborne asbestos fiber samples
  • Samples for health-effect studies and compliance checks should be taken at the worker's breathing zone
  • A fiber was defined as a particle with a length-to-diameter ratio equal to or greater than 3 to 1
  • Fiber counts should be expressed as fibers per cubic centimeter (milliliter) longer than 5 microns
  • Fibers greater than 5 microns in diameter should be excluded from counts because they are predominantly nonrespirable
  • Asbestos fibers should be counted using phase contrast microscopy
  • For research, optical and electron microscopy should be used to establish the ratio of fibers under 5 microns long to fibers over 5 microns long
  • In evaluating the exposure of the asbestos worker, free silica should be measured at strategic operations where it may be present in amounts approaching the silica exposure standards
  • For research, airborne samples should be analyzed for biologically active metals such as nickel, chromium, cobalt, manganese and iron
  • Countries using other methods should use the recommended procedures concurrently with their usual procedures
• The authors' conclusion: The subcommittee recommended that countries not routinely using the uniform procedures use them alongside their usual methods so that comparative data could be made available
• Limitations the authors state:
  • The subcommittee stated that the biological importance of submicron asbestos fibers was largely unknown
  • The subcommittee stated that counting fibers 5 microns or longer may not always be a valid index of exposure

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Asbestos Exposure.

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