Asbestos Related Disease Amongst Shipyard Workers - Mare Island Survey

Our plain-English summary of Asbestos Related Disease Amongst Shipyard Workers - Mare Island Survey, by P.L. Polakoff.

The study

• Author: P.L. Polakoff
• Published: Prepared for the Metal Trades Council, Mare Island Navel Shipyard. Vallejo, CA.
• Type of article: Report
• 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

The author prepared this document for the Metal Trades Council at Mare Island Naval Shipyard. It proposed long-term medical surveillance of shipyard employees and reported a preliminary chest x-ray survey. Much of it describes other researchers' studies of insulation workers and British dockyards, not this survey. In March 1977, 359 present and former Mare Island and Hunters Point Naval Shipyard workers had a single front-view chest x-ray. They came from many trades, each with more than 10 years since first asbestos exposure. At least two physicians read each film. Of the 359, 146 (40.66%) were read as normal and 213 (59.34%) as abnormal. The author described abnormal as lung tissue and/or lung lining changes compatible with asbestos-related disease. However, the detailed table also counts 12 films with other changes, such as tumors, lesions or infiltrates, as abnormal. The abnormal films were 129 mildly abnormal (36% of all 359) and 84 moderately abnormal. The report prints 21% for the 84, although 84 of 359 is about 23%. A detailed breakdown by x-ray finding, job, exposure length and smoking was not yet available.

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: Preliminary radiological (chest x-ray) survey, presented within a proposal for a long-term medical surveillance program; most of the document reviews earlier studies by other researchers
• Who was studied: 359 present and former workers of Mare Island and Hunters Point Naval Shipyards (San Francisco Bay Area), x-rayed in March 1977 at Herrick Memorial Hospital, Berkeley. They came from the whole range of shipyard occupations, including boilermakers, electricians, insulators, welders and laggers.
• Exposure: Asbestos exposure in shipyard work; each worker had more than 10 years since initial exposure. No fiber type or dose is given for the surveyed workers.
• Main results:
  • Of 359 workers, 146 (40.66%) had a normal chest x-ray and 213 (59.34%) an abnormal one (Table XXX).
  • Of all 359 workers, 129 (36%) were mildly abnormal and 84 were moderately abnormal. The text prints 21% for the moderately abnormal group, which does not match 84 of 359 (about 23%, worked out from those counts).
  • The author's text defines an abnormal reading as changes in the lung tissue (parenchyma) and/or lining of the lung (pleura) compatible with asbestos-related disease. Each film was read by at least two physicians.
  • Mildly abnormal subgroups in Table XXX, with percentages of all 359 workers: 75 (20.9%) had parenchymal changes only, 26 (7.2%) pleural changes only, and 28 (7.8%) both.
  • Moderately abnormal subgroups in Table XXX, with percentages of all 359 workers: 30 (8.4%) had parenchymal changes, 17 (4.7%) pleural changes, and 25 (7.0%) both. A further 12 (3.4%) had other changes such as tumors, lesions or infiltrates. These 12 are counted within the table's 359 total and among the abnormal films, and the table does not say they were asbestos-related.
  • Before the survey, in Fall 1976, Mare Island union members sent 25 chest x-rays to Dr. Irving Selikoff. 17 were interpreted as abnormal, compatible with asbestos-related disease.
• The authors' conclusion: The author proposed a long-term medical surveillance program aimed at minimizing future disease and death. The author stated that people employed in shipyards since World War II will remain a high-risk population for many years.
• Limitations the authors state:
  • A detailed analysis was not yet available. A breakdown by x-ray finding, job title, length of exposure and smoking history was still to come.

Topics

Medical terms in this study, explained in our Lexicon: Chest X-Ray, Insulator, Asbestos Exposure.

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