Merewether and Price Report
In 1930, Dr. E. R. A. Merewether (Medical Inspector of Factories in England) and Mr. C. W. Price (Engineering Inspector of Factories) released their Report on Effects of Asbestos Dust On the Lung's Report ("Merewether Report".) Merewether, E. R. A. and Price, C. W. Report on Effects of Asbestos Dust on the Lungs and Dust Suppression in the Asbestos Industry. H.M. Stationary Office: 1-34 (1930). View Report on Effects of Asbestos Dust on the Lungs and Dust Suppression in the Asbestos Industry.
The Merewether Report is widely recognized as a seminal event in the history of the recognition of asbestos hazards. It consists of two sections: Part I - Occurrence of Pulmonary Fibrosis and Other Pulmonary Affections in Asbestos Workers; and, Part II - Processes Giving Rise to Dust and Methods for Its Suppression. This note will focus on Part I and the next note on Part II. Each of these sections of the Merewether Report merit individual discussion.
Part I of the Merewether Report concludes that "the inhalation of asbestos dust over a period of years results in the development of a serious type of fibrosis of the lungs." (Id. at 5.) Merewether goes on to describe "Asbestosis" the "Pulmonary Fibrosis" of Asbestos Workers as:
The slow growth of fibrous tissue (scar tissue) between the air cells of the lung wherever the inhaled dust comes to rest. While new fibrous tissue is being laid down like a spider's web, that deposited earlier gradually contracts…and it gradually, and literally strangles the essential tissues of the lungs. (Id. at 9.)
To reach this conclusion, Merewether and Price examined 363 workers who worked in various asbestos factories for different periods of time. A work history was taken from each worker in order to exclude exposure to other common industrial dusts, including silica. Each worker's medical history also was examined to exclude any workers who had pre-existing respiratory problems prior to their asbestos exposure. Each of the worker's lungs were then examined using the best available means for each geographic area.
The Merewether Report found that: "In the lungs of those exposed to asbestos dust, angular particles derived from asbestos, and spicules of asbestos [were] found upon microscopical examination…" (Id. at 9.) Merewether further found that "These bodies have not been found to occur in any other human affliction." (Id.)
The Merewether Report found the distribution of workers with asbestos related fibrosis differed depending on the worker's age and length of employment:
Table 3: Incidence of Fibrosis Relative to Length of Employment (Id. at 10.)
| Years Employed | Number Examined | Cases of Fibrosis | Average age in years | ||
| Number | Group Incidence per cent | Of Group less cases of Fibrosis | Of cases of Fibrosis | ||
| 0-4… | 89 | 0 | -- | 24.2 | -- |
| 5-9… | 141 | 36 | 25.5 | 30.3 | 36.0 |
| 10-14… | 84 | 27 | 32.1 | 34.4 | 40.4 |
| 15-19… | 28 | 15 | 53.6 | 41.9 | 43.3 |
| 20 and over | 21 | 17 | 80.9 | 54.4 | 52.7 |
| Totals… | 363 | 95 | 26.2 | 30.1 | 41.4 |
Table 4: Incidence of Fibrosis Relative to Age (Id. at 11.)
| Age Group | Number Examined | Cases of Fibrosis | Average length of employment in years | ||
| Number | Group Incidence per cent | Of Group less cases of Fibrosis | Of cases of Fibrosis | ||
| Up to 19 | 23 | 0 | -- | 3.2 | -- |
| 20-20… | 150 | 14 | 9.3 | 6.2 | 8.7 |
| 30-39… | 100 | 30 | 30.0 | 9.1 | 12.2 |
| 40-49… | 47 | 31 | 65.9 | 11.3 | 14.2 |
| 50-59… | 29 | 11 | 37.9 | 9.7 | 16.0 |
| 60 and over | 14 | 9 | 64.3 | 16.0 | 19.3 |
| Totals… | 363 | 95 | 26.2 | 7.5 | 13.5 |
Both tables indicate "the outstanding importance of length of employment (and hence length of exposure to dust), and the negligible effects of age, on the production of fibrosis." (Id. at 11.)
Finally, the Merewether Report concludes that "From the data so far examined it seems clear that fibrosis of the lungs is a definite occupational risk amongst asbestos workers as a class. Furthermore, it appears that the risk falls most heavily on those longest employed and on those engaged in the more dusty processes." (Id. at 13.) Merewether also understood the concept of dose response in terms of the amount of dust coupled with the length of exposure reporting:
While it seems necessary for the production of generalized fibrosis of the lungs that a definite minimal quantity of dust must be inhaled, the lower the concentration of dust in the air breathed, the longer the lapse of time before the fibrosis is fully developed, and within a certain limit, the higher the concentration of dust, the sooner the fibrosis becomes fully developed and the more intense the involvement of the lung tissue. (Id. at 15.)
Merewether correctly points out that the amount of dust and length of exposure evidence is important because it shows "that the application of measures resulting in the reduction of the concentration of dust in the air will cause…the almost total disappearance of the disease, as the measures for the suppression of dust are perfected." (Id. at 15.) Merewether believed that asbestos could be controlled by controlling the dust each worker inhaled. Merewether also believed that workers should immediately be given an education of the risk of harm associated with the dust such that each worker had a "sane appreciation of the risk." (Id. at 17.)