E. R. A. Merewether, The Occurrence of Pulmonary Fibrosis and Other Pulmonary Affections in Asbestos Workers (1930)

A reprint of Dr. E. R. A. Merewether's article in The Journal of Industrial Hygiene (vol. 12, May 1930), the medical half of his British government inquiry into asbestos workers. It reviews the few earlier deaths, explains how the workers were chosen and examined, and describes the signs of asbestos fibrosis on examination and on X-ray. Merewether concluded that inhaling asbestos dust can produce a serious and even fatal lung fibrosis, different enough from silicosis that X-rays read against silicosis standards would underestimate it.

What it shows

This copy came from the files of Sumner Simpson of Raybestos-Manhattan: its cover is marked "Asbestosis England" and a routing slip carries his stamp and a note on the companion government report. It shows that the British findings reached the American industry in print in 1930. The full government report is Merewether and Price's Report on Effects of Asbestos Dust on the Lungs.

In Johns-Manville's chronology

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

Merewether publishes "The Occurrence of Pulmonary Fibrosis and other Pulmonary Affections in Asbestos Workers" in the Journal of Industrial Hygiene Vol. 12; "In view of the relationship between asbestosis fibrosis and silicosis the author has classified the main points of similarity and dissimilarity: -(1) Inhalation of asbestos dust, under favourable conditions of concentration of dust and length of exposure, will produce a serious and even fatal degree of pulmonary fibrosis; (2) the type of fibrosis produced, however, exhibits a number of divergences from that caused by the inhalation of free silica dust, and the outcome of these variations is not yet apparent; (3) the divergences noted so far are exhibited in the radiological picture, and on post mortem examination of the affected lungs, both in the gross morbid anatomy and in microscopic sections; (4) in the latter case the appearances of the asbestos fibrosis seem to be sufficiently distinctive not to permit of confusion between it and silicosis; (5) the radiological appearances of the asbestos type of fibrosis are more delicate, softer, and more diffuse than the silicotic fibrosis; (6) it follows, therefore, than an opinion as to the degree and intensity of an asbestos fibrosis, based on a comparison of the radiological changes with those shown in standard silicosis films, will be an underestimate; (7) in the absence of a full medical and industrial history, possibilities of confusion of the two types of fibrosis will arise in the interpretation of radio-grams; (8) there is evidence that other inorganic dusts, containing no free silica, may be productive of this fine type of fibrosis in varying degree."