Human occupational and nonoccupational exposure to fibers

Our plain-English summary of Human occupational and nonoccupational exposure to fibers, by N.A. Esmen, S. Erdal (Environmental Health Perspectives, 1990).

The study

• Authors: N.A. Esmen, S. Erdal
• Journal: Environmental Health Perspectives
• Published: 1990;88:277-86
• Type of article: Review
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 003847).

Abstract

Human exposure to fibers in occupational and nonoccupational environments has been a health concern for nearly a century. In this review, selected results from the literature are presented to highlight the availability, limitations, and interpretive difficulties associated with the past and current human fiber exposure data sets. In the traditionally defined asbestos fibers, large amounts of the data available suffer from the diversity of sample collection and analysis methods. Two simple generalizations suggest that occupational exposures are several orders of magnitude higher than that of environmental exposures; and currently extant data and the current routine measurement practices present significant difficulties in the consistent interpretation of the data with respect to health effects. The data on the human exposures to man-made vitreous fibers are much more complete than the data on asbestos exposure, while exposure data on other man-made fibrous materials are lacking. The human exposure data to many minerals which, at times, exist in fibrous habit, are very scanty, and in view of the biological activity of some of these fibers, this lack may be of significant concern.

In plain English

This was a review, not a new study. The authors gathered selected published measurements of people's exposure to fibers at work and outside work, and discussed what those data can and cannot show. They covered asbestos (chrysotile, amosite, crocidolite, anthophyllite, tremolite, actinolite), natural non-asbestos fibers such as erionite and wollastonite, man-made vitreous fibers such as glass wool, rock wool, slag wool and ceramic fibers, and other man-made fibers. They reported that older asbestos measurement methods convert to modern fiber counts only roughly, with possible errors of about an order of magnitude. They also reported that non-occupational asbestos exposures were generally several orders of magnitude lower than occupational ones, and that exposure data on tremolite and actinolite were virtually nonexistent. For erionite, reviewed work from three villages in central Cappadocia reported mesothelioma rates ranging from equal to four times those reported among asbestos worker cohorts. Man-made vitreous fibers had the most complete exposure data. The authors concluded that much of the available exposure data may be impossible to interpret in light of current knowledge. They also concluded that future measurements need more sophisticated chemical and physical analyses.

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 of selected published human fiber exposure data
• Who was studied: No new study population. The review covered published exposure measurements from workplaces (for example mining and milling, textiles, brake repair, drywall taping, insulation, shipyards, man-made fiber production) and from non-work settings (ambient air, water supplies, beverages, schools and public buildings).
• Exposure: Asbestos (chrysotile, actinolite, amosite, anthophyllite, crocidolite, tremolite). Natural non-asbestos fibers (wollastonite, erionite). Man-made vitreous fibers (glass wool, slag wool, rock wool, glass threads, ceramic fibers). Man-made nonvitreous fibers (silicon nitride, silicon carbide, carbon fibers).
• Main results:
  • Factors for converting older asbestos measurements (impinger, konimeter, thermal precipitator) to membrane filter phase contrast microscopy counts were judged to be only very general estimates, with possible errors of about an order of magnitude.
  • Occupational asbestos exposures were judged to be several orders of magnitude higher than environmental exposures.
  • Exposure data specific to tremolite and actinolite were lacking.
  • Reviewed lung tissue studies commonly found relatively few chrysotile fibers and relatively many amphibole fibers, even where exposure may have been mainly to chrysotile.
  • In one reviewed set of school measurements (71 locations sampled, measured by TEM), median airborne chrysotile was 0.0083 fibers/mL and median amphibole was 0.00065 fibers/mL.
  • In three villages in central Cappadocia with non-occupational erionite exposure, reported mesothelioma rates ranged from equal to four times the rates reported among various asbestos worker cohorts.
  • Estimates suggested exposures of about 1 fiber/mL in the early phases of mineral wool production, with a steady reduction to current levels from about 1945.
  • When man-made mineral fibers were used in confined or poorly ventilated areas, fiber exposures were about one order of magnitude higher than in fiber production.
• The authors' conclusion: The authors concluded that much of the available human fiber exposure data may be impossible to interpret in light of the biological and physical knowledge gained in the previous two decades. They also concluded that future measurements must include much more sophisticated chemical and physical analyses.
• Limitations the authors state:
  • The authors classified any fiber from a mineral that exists in asbestos habit as asbestos, and acknowledged that this classification is not rigorous.
  • The authors noted that applying fiber size categories developed for asbestos to other fibers may or may not be biologically appropriate.

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Environmental Exposure, Vitreous, Asbestos Exposure, Fibrous Habit.

Related studies

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• Introduction: INSERM-IARC-CNRS workshop on biopersistence of respirable synthetic fibers and minerals — J. Bignon, R. Saracci, et al. (1994)
• Biopersistence of respirable synthetic fibers and minerals: point of view of the chest physician — P. De Vuyst (1994)
• In vitro cytotoxicity and transforming potential of industrial carbon dust (fibers and particles) in syrian hamster embryo (SHE) cells — C. Darne, F. Terzetti, et al. (2010)
• Airway wall remodeling induced by occupational mineral dusts and air pollutant particles — A. Churg, J.L. Wright (2002)
• Occupational exposure to asbestos fibers resulting from use of asbestos gloves — B.S. Samimi, A.M. Williams (1981)

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