Cutaneous Reaction to Fiberglass

Our plain-English summary of Cutaneous Reaction to Fiberglass, by E.B. Heisel, J.H. Mitchell (1957).

The study

• Authors: E.B. Heisel, J.H. Mitchell
• Published: Industrial Medicine and Surgery, Volume 26 No12. December 1957
• Type of article: Journal article
• 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 1957 article is about fiberglass (glass fibers), not asbestos. The authors tested whether skin reactions to glass fibers were mechanical irritation or allergic sensitivity. They patch tested 50 white women aged 22 to 73 with no known Fiberglas contact. They used cut and unbroken fibers of different diameters, with and without sizing #630; 30 women then had fibers rubbed into their forearms daily for five days. They also patch tested 92 employees of a Fiberglas plant in Ashton, Rhode Island, and rubbed fibers on four rabbits. In the women's patch tests and the rubbing tests, unbroken fibers produced no reactions. Cut fibers caused reactions that increased with fiber coarseness. The coarsest rubbed fiber (#12) gave reactions in all rubbed subjects, severe in 43%; #150 produced no reaction in 73%. Of the 92 employees, patched with unbroken fibers, 88 showed no reaction; four had tiny papules that the authors attributed to glass spicules. No sensitization reactions were seen. Two people with marked dermographism developed urticaria. The authors concluded that reactions vary directly with fiber size, are largely mechanical irritation from sharp broken ends, and are transitory.

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: Experimental study: patch testing and repeated rubbing of glass fibers on human volunteers, patch testing and skin examination of factory employees, biopsies in five subjects, and rubbing experiments in rabbits
• Who was studied: 50 white women aged 22 to 73 with no known contact with Fiberglas, 30 of whom were also in the forearm rubbing experiment. 92 employees of the Fiberglas Corporation plant in Ashton, Rhode Island (30 employed less than one year, 30 employed one to six years, 32 employed six to 15 years). Four rabbits.
• Exposure: Fiberglas glass fibers of different diameters (#333 finest, #150, #37, and #12 coarsest, the last used only in air filters), cut short or left long and unbroken, with and without starch-base sizing #630. Applied by 48-hour patches on the back and by vigorous rubbing on the back or forearms.
• Main results:
  • In the 708 patch tests on the 50 women, there were no reactions to unbroken glass fibers, with or without sizing.
  • In the 50 women, cut fiber #150 caused fewer and less severe patch-test reactions than the coarser #37. There was essentially no reaction to the very fine #333 fibers. Reactions were small papules, which the authors interpreted as mechanical irritation.
  • The 92 employees were patch tested with unbroken fibers. Of these, 88 showed no reaction at all. One had two tiny papules under each patch, and three had one or two papules under one patch. The authors interpreted these papules as a foreign body reaction to glass spicules that had penetrated the epidermis.
  • When asked about skin trouble, 70 of the 92 employees had no complaints, 10 reported mild itching that disappeared after bathing, and two reported itching only while working on the hammermill. Ten had objective skin signs. One employee had severe generalized itching and eruption, with marked dermographism.
  • In the forearm rubbing experiment on 30 subjects, there were no reactions in areas rubbed with long, unbroken fibers.
  • In the 30 rubbed subjects, cut fiber #12 (the coarsest) gave positive reactions in all instances and severe reactions in 43% of subjects.
  • In the 30 rubbed subjects, cut fiber #150 produced no reaction in 73% and only a one-plus reaction in the rest. Fiber #37 produced less severe reactions than #12.
  • In the 30 subjects re-patch tested at the rubbed sites, no sensitization-type reactions (erythema, edema, vesiculation) and no delayed reactions were seen.
  • Biopsies from the rubbing sites showed no glass spicules or foreign body reactions in the epidermis or dermis.
  • The rubbing experiments in the four rabbits gave results comparable to those in humans.
  • Two people, one rubbing-experiment subject and one employee, developed severe urticaria on exposure to broken glass fibers. Both had marked dermographism.
• The authors' conclusion: The authors concluded that it is most difficult to sensitize humans to Fiberglas fibers or to sizing #630. They concluded that skin reactions to Fiberglas vary directly with fiber size, are due largely to mechanical irritation from sharp, broken ends, and are transitory.

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