Leroy Gardner to J. P. Woodard on Asbestos and Lung Cancer (1946)

A two-page letter of May 8, 1946, from Dr. Leroy Gardner, director of the Saranac Laboratory, to J. P. Woodard of Johns-Manville, returning a paper by Dr. Hueper on occupational cancer. Gardner notes that some 23 cases of asbestosis with lung cancer were now on record. He doubted the link, but wrote that "the number in the case of asbestosis is sufficiently great to be impressive." He reminded Woodard that in his experiments "over 80% of mice exposed to asbestos dust" developed lung tumors, against "some 15% or 20%" of mice exposed to other dusts.

What it shows

Gardner gave his own view that the link was "erroneous" and suggested that doctors looking for a cause of cancer were quick to publish such cases. Still, he urged a review of X-ray films of all Johns-Manville employees, and of the whole American asbestos industry, done by "somebody" outside the industry so that it "would then carry more weight." He wrote that the mouse experiments had not been designed to study cancer and had no controls for it. He had asked the National Cancer Institute for a $15,000 grant for a three-year study, which its committee turned down (see the NCI letters on his grant application). Five months later Gardner was dead, and the question of how to report the mouse findings passed to others (see Bowditch and Vandiver Brown, March 1947).

In Johns-Manville's chronology

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

Gardner advises J-M that asbestos-cancer link warrants additional independent study; Saranac results raise possibility of nexus. Letter from Gardner to Woodard dated 5/8/46 in which Gardner comments on Dr. Heuper's research concerning a possible link between asbestosis and pulmonary cancer. Gardner does not believe that there is a link but he does believe that a study should be done. He proposes to perform a comprehensive review of all x-ray films of Johns-Manville employees (or possibly the entire U.S. asbestos industry). He again describes the findings concerning the formation of tumors in certain mice which typically do not develop asbestosis but 80% of which did develop lung cancers as a result of the inhalation studies. He pointed out that this was in unexpected finding and thus no attempt had been made to select a strain of mice that either was or was not susceptible to tumors. Gardner reported that he made a research proposal to the National Cancer Institute to conduct further animal experimentation but that the grant had been denied.

Editor's note: J-M's description says 80% of the mice developed lung cancers. Gardner's letter says over 80% of the mice exposed to asbestos dust developed "tumors of the lung," against some 15 to 20 percent of mice exposed to other dusts.

Related documents

• R. R. Spencer and Ludvig Hektoen to Leroy Gardner Asking for a Statement on Asbestosis (1943)
• Leroy Gardner to Ludvig Hektoen on Asbestosis, Navy Insulation Work and Lung Cancer (1943)
• R. R. Spencer of the National Cancer Institute to Leroy Gardner on His Grant Application (1943)