Vandiver Brown and Manfred Bowditch Letters on Lung Cancer in Gardner's Mice (1947)

Five letters from March 1947 between Vandiver Brown, Johns-Manville's secretary and attorney, and Manfred Bowditch, field director of the Saranac Laboratory, written while others were finishing Leroy Gardner's asbestos report. Brown sent an Industrial Hygiene Digest item on Dr. King's experiments with short and long asbestos fibers. Bowditch replied with points from Gardner's notes, among them: "81.8% of mice inhaling long fibre asbestos develop lung cancer, a figure sixteen times that of the average for other dusts." Brown answered that he was "very much concerned" by that point. None of Gardner's interim reports, he wrote, "so far as I recall, had ever indicated any such abnormal incidence of lung cancer."

What it shows

Bowditch's notes also said that short fibers produced lung cancer in 13.6 percent of mice, seven times the average for other dusts, and that "these results are suggestive, rather than conclusive." On March 24 he told Brown where the cancer finding came from. It was page 8 of Gardner's "Outline of Proposed Monograph on Asbestosis" of February 1943, which Gardner had sent Brown on February 24, 1943. Brown had acknowledged it on March 1, 1943, saying photostats were being made for "the several interested companies." Brown replied on March 31 that he recalled Gardner "had made some reference to cancer" but not "such a marked tendency" in the animals. The letters show that the lung cancer finding had been in J-M's hands since 1943, and that it was one of the matters in play as the industry waited for the final report (see Gardner's 1946 letter to Woodard and the August 1947 meeting with Lanza).

In Johns-Manville's chronology

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

Letter from Vandiver Brown to Manfred Bowditch of Saranac, dated 3/12/47, forwarding an article from the February Industrial Hygiene Digest which discussed animal experimentation using both short and long fiber asbestos.

In a response dated 3/18/47, Bowditch notes that Gardner had principally differentiated between fibrous and particulate asbestos whereas the new article by Dr. King differentiated between long and short fibers. Bowditch reviewed Gardner's research notes which were in the process of being reviewed by Dr. Lynch and quoted certain relevant points including that in order to cause damage "fibers must be long enough so that they cannot be completely surrounded by phagocytic cells. 81.8 percent of mice inhaling long fiber asbestos developed lung cancer, a figure 16 times that of the average for other dusts. 13.6% of mice inhaling short fiber asbestos developed lung cancer, a figure 7 times the average for other dusts. These results are suggestive, rather than conclusive. Vandiver Brown wrote back on 3/21/47 expressing concern and surprise at the latter findings. On a blind carbon, he noted to J.P. Woodard "the finding referred to looks like dynamite. VB." Bowditch responded on 3/24/47 that the reference to cancer was in fact included in Gardner's "Outline of Proposed Monograph on Asbestosis" dated February, 1943 which was forwarded to Vandiver Brown on 2/24/43, and acknowledged on 3/1/43.

Editor's note: J-M's description quotes a blind-carbon note from Brown to J. P. Woodard calling the finding "dynamite." That note does not appear on the March 21, 1947, copy in this file. Gardner's 1943 outline and Brown's 1943 acknowledgment are not in this file either.