Dr. R. F. Liss to H. M. Jackson on Pneumoconiosis and Pleural Plaques at Manville, 1932–1971 (1971)

A confidential memo of July 23, 1971, from Dr. R. F. Liss, chief medical officer at J-M's Manville plant in New Jersey, to Hugh M. Jackson at headquarters, with two graphs and two tables. Compiled from the plant's medical records, they count new diagnoses of pneumoconiosis and of pleural plaques among Manville-Finderne workers each year from 1932 to 1971, with each worker's length of service. The pneumoconiosis table totals 505 cases.

What it shows

Liss lists the limits of his count. The films themselves were not reviewed, only X-ray reports, and he suggests that an expert review them. The large peaks in pneumoconiosis diagnoses in 1952 to 1954 and 1969 "correspond nicely" to new doctors joining the plant in 1951, 1953 and 1968, and to a lapse in X-ray studies from 1943 to 1948. Pleural changes of undetermined cause were left out, "though it is certain a good number of these would be diagnosed as asbestosis" with the films and work histories. Most of the cases had 10 to 35 years of service. The figures give a plant doctor's own count of more than 500 dust disease diagnoses at one plant, set beside Dr. Bristol's company-wide X-ray readings of the year before.

In Johns-Manville's chronology

Johns-Manville's own chronology of what the company knew describes this document as follows:

Dr. Liss (Manville plant doctor) prepares a report on the incidence of pneumoconiosis and pleural plaques occurring in J-M Manville/Finderne workers between the years 1930 and 1970. Data for the study was derived from X-ray reports. Liss includes information on duration of exposure.

Editor's note: J-M's description says the report covers the years 1930 to 1970; its tables run from 1932 to 1971.