Leroy Gardner, Interim Report on Experimental Asbestosis at the Saranac Laboratory (1939)

A seven-page report by Dr. Leroy Gardner to the asbestos companies sponsoring his animal experiments at the Saranac Laboratory. The experiments had set out to reproduce advanced asbestosis in animals, but guinea pigs breathing very finely ground Canadian chrysotile for 30 months showed little reaction, while a second group breathing longer fibres began to develop fibrosis within a year. Gardner concluded that grinding destroyed asbestos's capacity to irritate the lungs, admitted that "the anticipated results have not been realized," and asked the sponsors to renew their funding for another year.

What it shows

Gardner notes that the dust in the first animal room averaged 145 million particles per cubic foot of air, "29 times that set by the U.S.Public Health Service as the maximal permissable concentration of asbestos dust in industry" (the 5 million particle limit proposed in the 1938 Dreessen report). He also reports that he had been "until recently unaware" that unground fibre was being added to the hopper. He presented the results as having shown "the innocuousness of finely ground asbestos," which he thought might explain the lack of asbestosis in the mills at Thetford, while warning that dust control must be aimed at "the fibrous material in the air." The work was being done under the 1936 agreement that gave the sponsors control over publication (the Gardner agreement); Vandiver Brown sent this report on to Raybestos-Manhattan on December 26, 1939 (Brown's cover letter).

In Johns-Manville's chronology

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

Saranac Interim Report

Related documents

• Memorandum of Agreement Funding Gardner's Asbestos Experiments at Saranac Laboratory (1936)
• Vandiver Brown to Sumner Simpson on the 1938 Saranac Report and the Gardner Agreement (1939)
• Sumner Simpson to Vandiver Brown on Gardner's Use of Asbestosis Material (1939)