Radiographic search for asbestos-related disease in a naval shipyard

Our plain-English summary of Radiographic search for asbestos-related disease in a naval shipyard, by J.S. Felton (Annals of the New York Academy of Sciences, 1979).

The study

• Author: J.S. Felton
• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:341-52
• Cited by: 12 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. 004018).

Abstract

The Long Beach Shipyard underwent a chest x-ray survey of 6640 employees, or 88.6% of the total shipyard population, to determine the level of asbestotic changes. For computer classification purposes, the findings were divided into five groups: abnormal findings consistent with inhalation of asbestos fiber; normal; pulmonary fibrosis, nonspecific, questionable; and other findings not related to asbestosis. Asbestos-related abnormal findings, were encountered in 1061 workers, or 16.0%. No change was noted in 4806, or 72.4%. Pulmonary fibrosis was encountered in 140, or 2.1%. Other abnormalities not related to the inhalation of free asbestos fiber were encountered in 624, or 9.4%. The interpretation was questionable in nine individuals, or 0.1%. Of the male employees, 17.2% were positive for asbestos-related chest x-ray changes, and four women, or 0.8%, showed comparable findings. Of the men, 71.5% had normal chest x-rays, and 83.3% of the 402 women demonstrated normal films. Positive x-ray changes for asbestosis were encountered in a linear relationship when viewed by age of the worker. Employees aged 25--29 years exhibited 1.3% positive findings, and this level increased to a maximum of 38.2% positives among workers aged 65 years and over. Normal chest films descended, conversely, in a linear relationship. Similarly, the percentage of positive findings for asbestos-related disease increased in a linear configuration with length of service. Persons with 2--6 years of asbestos contact displayed 12.4% positive findings, while individuals with 22-26 years of work at the shipyard manifested 37.0% positive chest film findings. Although the shipyard was operational between 1943 and 1949, the system of allocation of badge numbers precludes the inclusion of these 7 years of work among persons who had had at least 26 years of service. When studied by work site, dividing the subjects into production and nonproduction personnel, it was found that production workers accounted for 74.5% of the asbestos-positive films. Overall, the 780 production workers manifested 11.8% of the positive findings of all persons studied, while nonproduction employees accounted for 4.1% of the positives out of the population studied. A figure that approximates the total finding of asbestos-related disease is 16.0%.

In plain English

The author reported a chest x-ray survey at the Long Beach Naval Shipyard, California, where asbestos lagging on steam piping was installed and removed during ship overhauls. The article did not name the fiber types. A June 1977 pilot sample of 500 production workers found 153 (30.5%) with changes consistent with asbestos inhalation, nearly all pleural thickening. The survey was then extended to all shipyard personnel, and 6640 of about 7500 employees (88.6%) took part. Overall, 1061 workers (16.0%) had abnormal findings consistent with asbestos inhalation, 4806 (72.4%) were normal, and 140 (2.1%) had nonspecific pulmonary fibrosis. These asbestos-related findings were seen in 17.2% of men and 0.8% of women. They rose with age, from 1.3% at ages 25-29 to 38.2% at 65 and over. They also rose with length of service, from 12.4% at 2-6 years to 37.0% at 22-26 years. Among 6625 employees classified by work assignment, production workers made up 4,865 (73.4%) and accounted for 780 of the 1,047 positive films (74.5%). The author noted that length of service came from badge numbers that miss earlier employment.

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: Cross-sectional chest x-ray (radiographic) survey of shipyard employees during 1977, preceded by a pilot sample of 500 production workers
• Who was studied: 6640 of approximately 7500 employees (88.6%) of the Long Beach Naval Shipyard, California, x-rayed in 1977 (6157 men, 483 women)
• Exposure: Shipyard work involving asbestos lagging (insulation) on high-pressure steam piping, installed and removed during ship overhaul and repair; fiber type not specified; length of service taken from badge numbers; production versus nonproduction work assignment
• Main results:
  • In the June 1977 pilot sample of production workers, 153 persons (30.5%) had changes consistent with asbestos inhalation
  • In the pilot, nearly all positive subjects showed pleural thickening; some also had pulmonary fibrosis
  • Of all 6640 surveyed, 16.0% (1061) had abnormal findings consistent with asbestos inhalation
  • Of all 6640 surveyed, 4806 (72.4%) had normal films
  • Of all 6640 surveyed, 140 (2.1%) had nonspecific pulmonary fibrosis; counting these as asbestos-related would raise the total to 1201 (18.1%)
  • Asbestos-related findings were seen in 17.2% of male employees and 0.8% of female employees (4 women)
  • Positive findings rose with age: 1.3% of workers aged 25-29 versus 38.2% of those aged 65 and over
  • Positive findings rose with length of service: 12.4% at 2-6 years versus 37.0% at 22-26 years
  • Among the 6625 employees classified by work assignment, production workers numbered 4,865 (73.4%) and had 780 (74.5%) of the asbestos-positive films
  • The 74.5% is out of 1047 asbestos-positive films in the work-assignment analysis, not the 1061 in the full survey
  • The 780 positive production workers equalled 11.8% of all 6625 people studied, and positive nonproduction workers equalled 4.1% of the same total. These are shares of the whole population, not rates within each group.
• The authors' conclusion: The author concluded that the significant findings were limited to the 16.0% of those surveyed with abnormal findings consistent with asbestos inhalation (18.1% if pulmonary fibrosis is counted), with positive findings increasing with age and length of service
• Limitations the authors state:
  • Length of service came from badge numbers. Rehired workers get new numbers, and service before 1951 is not reflected.
  • Records of exposure at earlier jobs or other shipyards were not available.
  • Participation was incomplete. About 860 employees were not yet fully examined, and some refused.
  • Pulmonary fibrosis without pleural thickening could be due to asbestos or to other dust.
  • Totals vary between tables because of computer error or missing identifying data.
  • The survey was preliminary. Smoking history and pulmonary function had not yet been correlated with x-ray findings.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Shipyards and maritime work.

Medical terms in this study, explained in our Lexicon: Chest X-Ray, Pulmonary Fibrosis.

Related studies

• Prevalence of radiographic abnormalities among Northern California shipyard workers — P.L. Polakoff, B.R. Horn, et al. (1979)
• Case-control study of lung cancer in civilian employees at the Portsmouth Naval Shipyard, Kittery, Maine — R.A. Rinsky, J.M. Melius, et al. (1988)
• A nested case-control study of lung cancer risk and ionizing radiation exposure at the portsmouth naval shipyard — J.H. Yiin, S.R. Silver, et al. (2007)
• A visual historical review of exposure to asbestos at puget sound naval shipyard (1962-1972) — D.M. Hollins, D.J. Paustenbach, et al. (2009)
• Asbestos exposure control at Puget Sound Naval Shipyard — R.R. Beckett (1976)
• Experience with asbestos disease and its control in Great Britain's naval dockyards — P.G. Harries (1976)

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