Dust control in a conventional asbestos textile factory

Our plain-English summary of Dust control in a conventional asbestos textile factory, by H.C. Lewinsohn, C.A. Kennedy, J.E. Day, et al (Annals of the New York Academy of Sciences, 1979).

The study

• Authors: H.C. Lewinsohn, C.A. Kennedy, J.E. Day, P.H. Cooper
• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:225-41
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy.

Summary of the article

The authors, from Raybestos-Manhattan, described how the company reduced asbestos dust at its Marshville asbestos textile plant while continuing to make asbestos textiles by conventional methods. They set this against US standards that lowered the permissible limit to 2 fibers/cm3 (8-hour time-weighted average) from July 1976. When the company acquired the plant in 1969, dust counts were barely below 12 f/cc. Raw chrysotile fiber was handled by hand, and many operations had little or no exhaust ventilation. Product and process changes followed between 1969 and 1973. In June 1975 a 'clean system' plan for asbestos textiles costing $12.3 million was approved, of which $2.6 million was for Marshville. The work, completed in July 1977, included closed pneumatic fiber handling with no manual handling of raw asbestos, double-enclosed and exhausted carding machines, and enclosed and exhausted winders. Other measures were wet weaving with resin treatment, a 50,000-square-foot smooth-surfaced addition, fresh make-up air units, and a 110,000 CFM baghouse with bagged waste removal. Work practices, protective equipment, disciplinary enforcement, more clean-up staff, employee education and dust monitoring were also introduced. Mean fiber counts were compared for 1969, 1974 and 1978. The authors reported that all levels were maintained below 1 fiber/ml (8-hour TWA) and stressed the importance of work practices. They noted that such changes over time complicate epidemiological dose-response studies.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This article, by authors affiliated with Raybestos Manhattan, described how the company reduced asbestos dust at its Marshville asbestos textile plant, which it acquired in November 1969. The plant processed chrysotile asbestos, brought in as compressed bales, into textiles and friction yarns. According to the authors, dust counts at acquisition were barely below 12 fibers per cubic centimeter. The changes included enclosed feed hoppers under negative pressure, open only at the feed end where bags were opened with air drawn away from the operator. They also included pneumatic fiber transfer, double-enclosed carding machines, enclosed winders, and wetted yarns in weaving. Work practices were backed by graduated discipline and respirators for emergencies and special clean-ups. The project was completed in July 1977. The authors reported that all levels were then kept below 1 fiber/ml as an 8-hour time-weighted average. The authors concluded that good work practices were essential, and that the plant probably ranked as the cleanest of its kind in the world. They added that such changes over time make dose-response studies in industry difficult.

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: Descriptive report of an engineering dust-control program at a single company plant, written by company-affiliated authors
• Who was studied: The Marshville asbestos textile plant of Raybestos-Manhattan, acquired in November 1969. It had about 150,000 square feet and employed slightly over 200 people.
• Exposure: Chrysotile asbestos fiber (including Cassiar fiber Grades A and AA and Bells 3-T) blended with carrier fibers such as cotton and rayon. It was processed by preparation, carding, spinning, twisting, winding and weaving into asbestos textiles and friction yarns.
• Main results:
  • At the time of acquisition in 1969, plant dust counts were barely below 12 fibers per cubic centimeter, the ACGIH-recommended maximum allowable concentration.
  • Feed hoppers on the blending line were enclosed and under negative pressure. They were open only at the feed end, where bags of asbestos were opened with air drawn away from the operator.
  • The action plan reduced fiber counts to less than 1 fiber per cubic centimeter and considerably increased plant capacity.
  • The authors reported that, after the project, all levels were maintained below 1 fiber/ml as an 8-hour time-weighted average.
  • Dust at the carding machines was controlled by double enclosures exhausted to a baghouse.
  • All weaving was changed to use wetted yarns.
  • Spinning, twisting and weaving were not enclosed and ventilated; all other processes were.
  • The authors reported that manufacturing cost per pound of product did not increase, despite higher energy costs.
• The authors' conclusion: The authors concluded that work practices were essential to keeping dust low, and that the Marshville plant probably ranked as the cleanest plant of its kind in the world. They also said the paper illustrates the difficulties of industry dose-response epidemiological studies when sampling, raw materials and engineering controls change over time.
• Limitations the authors state:
  • The authors noted that experience would determine what further improvements could or needed to be made, and that operating procedures might have to be modified.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestos textiles, Asbestosis.

Medical terms in this study, explained in our Lexicon: Dust Control, Raybestos-Manhattan, Asbestos Textiles, Time-Weighted Average (TWA), Chrysotile, Carding, Dose-response relationship.

Related studies

• Dust exposure and mortality in an American factory using chrysotile, amosite, and crocidolite in mainly textile manufacture — A.D. McDonald, J.S. Fry, et al. (1983)
• Technological feasibility of the 2 fibers/cc asbestos standard in asbestos textile facilities — R.A. Curtis, P.H. Bierbaum (1975)
• Follow-up study of chrysotile asbestos textile workers: cohort mortality and case-control analyses — J.M. Dement, D.P. Brown, et al. (1994)
• Dust exposure and mortality in an American chrysotile textile plant — A.D. McDonald, J.S. Fry, et al. (1983)
• Occupational exposure to textile dust and lung cancer risk: Results from the ICARE Study — S. Ben Khedher, M. Neri, et al. (2018)
• Health progress in an asbestos textile works — J. Mitchell (1961)

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