Annual Report of the Chief Inspector of Factories for the Year 1947, on Asbestosis and Lung Cancer (1949)

The cover and pages 79–81 of the British Chief Inspector of Factories' annual report for 1947, presented to Parliament in January 1949. In a section headed "Asbestosis and Carcinoma of Lung," the Factory Department reports that of 235 deaths from or with asbestosis that came to its notice from 1924 through 1946, 31 (13.2 percent) showed cancer of the lungs or pleura. Among 6,884 silicosis cases from 1930 to 1946, the figure was 1.32 percent. J-M's copy also holds a 1950 Canadian Medical Association Journal article in which E. R. A. Merewether, Britain's Senior Medical Inspector of Factories, repeats the comparison; that article is not posted here.

What it shows

This is the first official count suggesting that people with asbestosis died of lung cancer far more often than people with silicosis, about ten times as often in this series. The report also found that the asbestosis deaths with cancer had a longer average exposure (16.5 years against 13.4) and came at an older average age (52.1 against 44.2). In the 1950 article, Merewether calls the possible link between asbestosis and lung cancer "a point of considerable interest." The copy carries a J-M library stamp, so the company had these figures in its files. They came while Saranac Laboratory's mouse experiments were raising the same question (see Bowditch and Vandiver Brown on Gardner's cancer findings).

In Johns-Manville's chronology

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

Merewether, Britain's Chief Inspector of Factories, writes report which identifies possible asbestosis-cancer link. Reviewed all deaths in Britain where asbestosis was cause or co-existing condition 1926-46; 13.2% had lung cancer whereas predicted was 1.35%.