Health of Fibrous Glass Workers

Our plain-English summary of Health of Fibrous Glass Workers, by J.L. Konzen (1968).

The study

• Author: J.L. Konzen
• Published: Industrial Hygiene Foundation 33rd Annual Meeting. October 16th 1968
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This 1968 conference presentation, by the medical director of Owens-Corning Fiberglas Corp., reviewed the health effects of fibrous glass. It is not about asbestos. The author summarized earlier animal, worker and skin studies, plus unpublished work. In a two-year inhalation study of rats and hamsters, with one year completed, all animals so far showed only a dust cell reaction without collagen formation. Wright's review of chest X-rays of 1400 workers at the oldest continuously producing fibrous glass plant found no distinctive shadow typical of fibrous glass exposure. Preliminary analysis of lung function tests in about 225 randomly selected employees at that plant suggested only an age effect. The skin studies reviewed attributed irritation to pricking by broken fibers, not allergy. In a recent double-blind study by Heisel, coated and dyed fibers caused no irritation when the largest fiber diameter was under about 4.8 microns. The author described this work as documenting fibrous glass as a biologically inert dust. The author noted that plants with low turnover raise the question of a selected population.

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• Design: Review presented at a conference, including some unpublished and preliminary studies
• Who was studied: Laboratory animals (rats, hamsters) and fibrous glass workers, including 1400 workers whose chest X-rays were reviewed and about 225 randomly selected employees tested at the world's oldest continuously producing fibrous glass plant
• Exposure: Fibrous glass (wool and textile fibers), uncoated or coated with phenol formaldehyde resin or starch; no asbestos exposure is studied
• Main results:
  • Two-year inhalation study in rats and hamsters (one year completed): only a dust cell reaction without collagen formation in all animals so far
  • Wright's review of chest X-rays of 1400 fibrous glass workers found no distinctive X-ray shadow typical of fibrous glass exposure
  • Preliminary analysis of lung function and questionnaire data from about 225 randomly selected employees suggested only an age effect
  • Earlier skin studies concluded that irritation came from repeated pricking of the upper skin by broken fibers, with no allergic response
  • In a recent double-blind study by Heisel, coated and dyed fibers caused no skin irritation if the largest fiber diameter was less than about 4.8 microns
• The authors' conclusion: The author described the body of work as documenting fibrous glass as a biologically inert dust
• Limitations the authors state:
  • The author noted that in plants with low employee turnover the workforce may be a selected population, and said a study with the USPHS using social security data was intended to address this
  • The animal inhalation study was only one year into its two-year course

Topics

Medical terms in this study, explained in our Lexicon: Owens-Corning Fiberglas, Collagen, Chest X-Ray.

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