F. L. Pundsack to C. B. Burnett and Others on Caution Labels for Micro-Fibers (1970)

A one-page memo of June 9, 1970, from F. L. Pundsack of J-M's Research and Engineering Center to C. B. Burnett, J-M's president, and ten others, including Dr. T. H. Davison and Dr. G. W. Wright. Pundsack writes that he knows of no evidence that inhaling J-M's "Micro-Fibers" is harmful to humans, but that the material "has induced significant tissue response in two separate animal experiments" in which it was injected into the pleural lining: Dr. William Smith of Fairleigh Dickinson University reported "the formation of mesothelioma tumors" in hamsters, and Dr. John Davis of Cambridge University reported large spreading "granulomas" in mice. He recommends labeling Micro-Fiber packages with a caution notice.

What it shows

The proposed label said only: "Inhalation of Micro-Fibers should be avoided by use of proper industrial hygiene practices." It gave no reason. For comparison Pundsack enclosed the Celite label, which warned that diatomaceous earth dust "may be harmful." The subject was to go to the Environmental Health Policy Committee on June 15. The memo does not say what Micro-Fibers were made of.

In Johns-Manville's chronology

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

F.L. Pundsack recommends to C.B. Burnett, dated 6/9/70, that J-M's micro-fiber packages be labeled with a caution notice. He states that although there is no evidence which indicates that inhalation of micro-fibers is harmful to humans, it is known that "it has induced significant tissue response in two separate animal experiments in which it was injected in relatively large does directly into the pleural lining."