Asbestos dust concentrations in ship repairing: a practical approach to improving asbestos hygiene in naval dockyards

Our plain-English summary of Asbestos dust concentrations in ship repairing: a practical approach to improving asbestos hygiene in naval dockyards, by P.G. Harries (The Annals of Occupational Hygiene, 1971).

The study

• Author: P.G. Harries
• Journal: The Annals of Occupational Hygiene
• Published: 1971;14(3):241-54
• Cited by: 29 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. 004285).

Abstract

A survey of the asbestos fibre concentrations associated with work involving asbestos insulating materials has been undertaken in Devonport Dockyard. The results show that application and removal of asbestos materials both create high dust concentrations, and measures to reduce the health hazards associated with such processes are described. The results of sampling after the introduction of preventive measures are briefly presented and these results indicate that the precautions are effective in reducing the asbestos dust concentrations in shipyard insulation processes.

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

In plain English

This survey measured airborne asbestos fibre levels during insulation work on naval ships refitted at Devonport Dockyard. To show past conditions, the bulk of samples came from ships with old materials, an aircraft carrier and a cruiser, in 1967; other processes, especially applying insulation, were sampled in destroyers, frigates and larger vessels. Air was drawn through membrane filters in work areas and near workers' faces, and fibres were counted by microscope. Removing sprayed crocidolite produced levels above 200 fibres/cm3 at the stripping areas. Short samples near men bagging crocidolite debris showed 1000-2000 fibres/cm3. Dust spread through the ship, reaching 109 fibres/cm3 at the top of a ladder from the stripping area. Removing pipe lagging gave mean general levels of 171 fibres/cm3 in boiler rooms and 88 fibres/cm3 in engine rooms. Applying lagging gave much lower levels. After new precautions, most samples taken in May-October 1969 were below 1 fibre/cm3. The author noted that this also reflected less asbestos being used. The author concluded that all asbestos insulation processes produced more than 2 fibres/cm3. The study measured dust, not disease.

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: occupational hygiene survey measuring airborne asbestos fibre concentrations (membrane filter sampling, fibres counted by phase contrast microscopy), with follow-up sampling after preventive measures
• Who was studied: Work processes and workers on naval ships being refitted at Devonport Dockyard. To show past conditions, the bulk of samples was taken in ships containing the old materials, an aircraft carrier and a cruiser, in 1967. Other processes, especially applying insulation, were sampled in destroyers and frigates as well as larger vessels. Follow-up samples were taken May-October 1969.
• Exposure: Application and removal of asbestos insulation: sprayed crocidolite, pipe sections of 90 per cent amosite, calcium silicate with 15 per cent asbestos, asbestos cloth (chrysotile), rope, cement, acoustic panels, and the asbestos mattress shop
• Main results:
  • During removal of sprayed crocidolite from an aircraft carrier, concentrations were above 200 fibres/cm3 at the stripping areas
  • Short samples in the breathing zones of men bagging crocidolite debris showed 1000-2000 fibres/cm3
  • Dust spread through the ship: 109 fibres/cm3 at the top of a ladder from the stripping area to the deck above (and 30 fibres/cm3 two decks above)
  • During removal of pipe and machinery lagging, mean general atmosphere levels were 171 fibres/cm3 in boiler rooms and 88 fibres/cm3 in engine rooms, with similar breathing zone levels in both (91-97 fibres/cm3)
  • Dust concentrations during application of pipe lagging were much lower than during stripping
  • Blowing down debris with an air hose gave 480 fibres/cm3, and sweeping amosite debris gave 564 fibres/cm3
  • Ripping asbestos cloth treated with a dust suppressant gave concentrations all less than 1 fibre/cm3
  • After precautions (May-October 1969), 343 engine room samples were below 1 fibre/cm3 while 17 samples had a mean of 2.9 fibres/cm3; in boiler rooms 273 samples were below 1 fibre/cm3 and 9 (mean 2.7 fibres/cm3) were above 1 fibre/cm3
  • In smaller compartments after precautions, 327 samples were below 1 fibre/cm3 and 25 samples had a mean of 31.8 fibres/cm3
• The authors' conclusion: The author concluded that all processes involving asbestos insulating materials in Naval Dockyards gave rise to concentrations above 2 fibres/cm3, that many reached 50 fibres/cm3 or more, and that personal protection would be needed for many years
• Limitations the authors state:
  • The author recognised the disadvantages of small, quick samples
  • Spraying of asbestos could not be measured in this study because the process had stopped in 1963
  • The lower post-precaution results also reflect the reduced amount of asbestos now used in naval ships, not only the cleaning methods
  • Accurate time-weighted exposure estimates for insulating workers are not possible without continuous monitoring of every process

Topics

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

Related studies

• UK Naval Dockyards asbestosis study: survey of the sample population aged 50-59 years — C.E. Rossiter, P.G. Harries (1979)
• Royal Naval dockyards asbestosis research project: nine-year follow-up study of men exposed to asbestos in Devonport Dockyard — C.E. Rossiter, J.R. Heath, et al. (1980)
• A comparison of mass and fibre concentrations of asbestos dust in shipyard insulation processes — P.G. Harries (1971)
• Asbestos hazards in naval dockyards — P.G. Harries (1968)
• Correlation between fibre content of the lungs and disease in naval dockyard workers — J.C. Wagner, C.B. Moncrieff, et al. (1986)
• The rise and fall in incidence of malignant mesothelioma from a British Naval Dockyard, 1979-1999 — A.K. Hilliard, J.K. Lovett, et al. (2003)

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