Saranac Laboratory, First Interim Report on Asbestosis and Pulmonary Cancer to the Quebec Asbestos Mining Association (1952)

An eleven-page interim report of May 7, 1952, submitted by Dr. Arthur J. Vorwald of the Saranac Laboratory to the Quebec Asbestos Mining Association, on an experiment testing whether inhaled asbestos dust raised the rate of lung tumors in mice. After 14 months of exposure to chrysotile dust from Thetford, Quebec, 9.5 percent of the exposed mice had lung tumors against 5.5 percent of the unexposed controls. Saranac reported that the difference was not yet statistically significant, but that "there does appear to be a trend toward a greater incidence of tumors in the exposed animals," which might prove significant as more animals were examined.

What it shows

The report called the experiment "now in its most important phase," since tumors had begun to rise at 14 months and the rise was "more pronounced" in the dust-exposed mice. It noted that if the exposed group's rate had been 11 percent instead of 9.5, the difference would already have been significant. The study had been arranged for the Quebec mining companies, J-M's Canadian subsidiary among them; its planning is covered in the annotated Saranac proposal and Woodard's memo on the meeting about the cancer study. Some months earlier Vorwald had told J-M he was "morally certain" there was no link between asbestos and cancer (see Dr. Kenneth Smith's October 1951 memo to C. M. McGaw).

In Johns-Manville's chronology

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

On 5/7/52, Saranac submits First Interim Report re QAMA study of asbestosis/pulmonary cancer link. Tumors beginning to increase in test animals (mice).

Related documents

• J. P. Woodard, Minutes of the Saranac Lake Meeting on the Quebec Asbestos and Lung Cancer Study (1950)
• Vandiver Brown to J. P. Woodard on Approval Before Publication of Saranac Results (1950)
• J. P. Woodard to Vandiver Brown on Publication of Saranac Test Results (1950)
• Vandiver Brown to J. P. Woodard on Dr. Vorwald's Aluminum Hydroxide Proposal and Publication Rights (1950)
• George K. Foster to J. P. Woodard on Preparing a Lung Cancer Research Program for the Quebec Asbestos Mining Association (1950)
• Saranac Laboratory, Proposal on Asbestosis and Pulmonary Cancer to the Quebec Asbestos Mining Association (1950)