Exposure of employees to man-made mineral fibers: mineral wool production

Our plain-English summary of Exposure of employees to man-made mineral fibers: mineral wool production, by N.A. Esmen, Y.Y. Hammad, M. Corn, et al (Environmental Research, 1978).

The study

• Authors: N.A. Esmen, Y.Y. Hammad, M. Corn, D. Whittier, N. Kotsko, M. Haller, R.A. Kahn
• Journal: Environmental Research
• Published: 1978;15(2):262-77
• Cited by: 23 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004980).

Abstract

This paper reports the results of a study in which employee exposure to mineral wool fibers in the mineral wool production industry was measured. Data for this study were collected in five plants operated by three different corporations. The results of the study indicate that the average exposure is about 0.1 to 0.5 fibers/ml. The results also indicate that despite operational diversities among the plants the size and length distributions of airborne fibers were consistent. It was also found that there is an excellent correlation between average total suspended particulate matter and average fiber exposure for types of work activity found in the plants.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This study measured the airborne mineral wool fiber and total dust that employees breathed in five mineral wool production plants run by three corporations. It measured mineral wool fibers, not asbestos, although fibers were counted with methods developed for asbestos. Workers wore personal samplers in their breathing zone, and their tasks were grouped into nine work-activity categories. Average exposure was about 0.1 to 0.5 fibers/ml, and overall totals were approximately 0.1 fibers/ml. The highest averages were in trimming, sawing, cutting and finishing work, quality control, and janitorial work. Averages for similar operations differed fivefold or more between plants. About 50-60% of fibers were under 3 µm in diameter, and few were under 1 µm. For individual samples, dust and fiber levels matched very weakly. Averages by work activity matched closely, with a correlation of 0.934. Using this relationship and older dust counts reported by other researchers, the authors suggested past average exposures of about 1.2 to 2.5 fibers/ml, and about 0.5 to 1.0 fibers/ml in the late 1940s and early 1950s.

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: industrial hygiene exposure survey using personal breathing-zone air samples, with an estimate of historical exposures
• Who was studied: employees of five mineral wool production plants (Plants A to E) operated by three different corporations; the plants employed approximately 80, 160, 400, 90 and 130 persons; the article does not state the location or the years of sampling
• Exposure: airborne mineral wool fibers (man-made mineral fibers made from slag, rock and similar materials) and total suspended particulate matter (TSPM) in nine work-activity categories; fibers were counted by phase contrast and electron microscopy using a method based on asbestos counting
• Main results:
  • Across the plants, average exposure was about 0.1 to 0.5 fibers/ml
  • Overall total fiber concentrations were approximately 0.1 fibers/ml; the highest overall averages were in Production B (trimming, sawing, cutting and finishing), quality control and janitorial areas
  • Overall average TSPM concentrations ranged from 0.6 mg/m3 to 3.98 mg/m3
  • Average exposures in different plants differed by fivefold or more for similar processing operations
  • Relatively low concentrations were measured in Production A, where workers are in intimate contact with the fibers
  • Fiber size and length distributions were consistent across plants; on average approximately 50-60% of fibers were less than 3 µm in diameter, and relatively few were less than 1 µm in diameter
  • For individual samples, the correlation between TSPM and fiber concentration was very weak
  • Average TSPM and average fiber concentration by work-activity class correlated closely (correlation coefficient 0.934); the rank correlation between plants' dust and fiber rankings was 0.82
  • Using older impinger dust counts reported by Carpenter and Spolyar, the authors suggested an average historical exposure of about 1.2 to 2.5 fibers/ml
  • For the late 1940s and early 1950s, the authors suggested exposures of generally about 0.5 to 1.0 fibers/ml
• The authors' conclusion: The authors concluded that the correlation between average dust and average fiber levels may be used to estimate past fiber exposures. They proposed approximating fiber concentration as TSPM multiplied by about 0.08; the margin is printed as 0.04 with a damaged symbol.
• Limitations the authors state:
  • Not all individuals in each area could be sampled; workers were randomly selected
  • The estimating formula applies only to mineral fiber and is based only on averages of dust concentrations
  • Estimating historical levels is made harder by having to convert between weighed dust and impinger particle counts
  • Early in the study, a different electron microscope method was used
  • The work-activity categories may not match the job titles used by the companies or unions

Topics

Medical terms in this study, explained in our Lexicon: Mineral Fiber.

Related studies

• Measurement and analysis of chemically changed mineral fibers after experiments in vitro and in vivo — K.R. Spurny (1983)
• Historical cohort study of US man-made vitreous fiber production workers: I. 1992 fiberglass cohort follow-up: initial findings — G.M. Marsh, A.O. Youk, et al. (2001)
• Historical cohort study of US man-made vitreous fiber production workers: II. Mortality from mesothelioma — G.M. Marsh, M.J. Gula, et al. (2001)
• Environmental measurements of total dust and fiber concentration in manufacturer and user of man-made mineral fibers — J.H. Kim, H.S. Chang, et al. (1999)
• Mortality among a cohort of US man-made mineral fiber workers: 1985 follow-up — G.M. Marsh, P.E. Enterline, et al. (1990)
• Comparative epidemiology of men exposed to asbestos and man-made mineral fibers — J.R. Goldsmith (1986)

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