Tabershaw-Cooper Report Covering Their Seminar on Health Hazards of the Insulator

Our plain-English summary of Tabershaw-Cooper Report Covering Their Seminar on Health Hazards of the Insulator.

The study

• Published: NICA Outlook
• Type of article: Trade 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 was not a research study. It was a two-part magazine transcript of seminar questions and answers from Portland, Los Angeles and San Francisco. The seminars were attended by representatives of insulation contractors and asbestos workers. They followed a short presentation by Tabershaw, Cooper and Balzer, medical advisors to the Western States Asbestos Health Plan; the article does not say who asked or answered each question. The answers said the plan began in October 1968 and that two-thirds or more of the men had been examined in Portland and Seattle. They said animal evidence showed fibrous glass to be inert. They said there was so far no evidence of chronic lung effects from glass, though insulators' mixed exposure made glass hard to judge. They did not know whether the smaller glass fibers now used would cause chronic damage, and reserved judgement over new resin coatings. They reported duct air fiber levels of about one fiber per liter. They also reported about 50 Bay Area mesotheliomas over 10 years, most with no asbestos connection found. Several figures in the supplied text were too garbled to use.

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: Edited verbatim transcript of seminar questions and answers published in a trade magazine (not a research study)
• Who was studied: Seminars attended by representatives of the Associated Insulation Contractors of the Western States and the Western States Conference of Asbestos Workers. The seminars were held in Portland, Oregon, and in Los Angeles and San Francisco, California. The article does not say who asked or answered each question.
• Exposure: Exposures of insulating workers: asbestos fibers, glass fibers, solvents, mineral wool and fumes. Fibrous glass and duct linings were also discussed.
• Main results:
  • The answers stated that the Western States Asbestos Health program went into effect in October 1968.
  • In the two oldest examination programs, Portland and Seattle, two-thirds or more of the men had been examined.
  • The answers stated that experience indicated 50% of workers take up the offer of an examination in the first year.
  • The answers stated that animal evidence so far showed fibrous glass to be inert and not to cause the kind of reaction seen with asbestos. They also said the answerers had not themselves done animal experiments with fibrous glass.
  • The answers stated that it was not known for sure whether the smaller glass fiber sizes now being used would produce chronic damage.
  • Because new resin coatings and trace metals were being used on glass fibers, the answers stated that judgement was being reserved in some areas on the total use of glass.
  • From about 2 years of round-the-clock measurement of duct systems, the answers stated that the amount of glass coming out of ducts was about the same as in the general atmosphere, about one fiber per liter.
  • The answers reported about 50 mesotheliomas found in the San Francisco Bay Area over the last 10 years. In most of these no connection with asbestos could be found.
  • The answers stated that in a study of sputum samples from a naval shipyard, many people who had never been insulating workers showed asbestos bodies in their sputum.
  • The answers stated that some cases of asbestosis are called chronic bronchitis and emphysema. More common than misdiagnosis, they said, is the same man having chronic bronchitis, emphysema and asbestosis together.
  • On masks, the answers stated that there is some evidence that a poorly fitting mask is worse than no mask at all.
• The authors' conclusion: The view given in the answers was that fibrous glass did not appear to produce chronic health effects, and that asbestos and glass are in entirely different ball parks in terms of chronic lung hazards. The answers still advised that glass exposures be controlled.
• Limitations the authors state:
  • The answers stated that glass effects could not be judged in insulating workers alone, because those workers' exposures were a mixture of glass and asbestos.
  • The answers stated that not many workers had yet been exposed to the newer, smaller-diameter glass fibers for long periods of time.

Topics

Medical terms in this study, explained in our Lexicon: Insulator, Mesothelioma.

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