Dr. Kenneth W. Smith to Westinghouse Electric Corporation on J-M 450 Insulating Cement (1960)

A one-page letter of June 1, 1960, from Dr. Kenneth W. Smith, J-M's medical director, to Mr. Speicher, administrator of headquarters industrial hygiene at the Westinghouse Electric Corporation in East Pittsburgh, Pennsylvania, answering his request about health and safety hazards of J-M 450 Insulating Cement and similar products. Smith returns Westinghouse's material analysis sheets, completed by J-M's quality control staff, and writes: "While it is recognized that continued inhalation of asbestos fibres over a long period of time and sufficient concentration can cause some pulmonary damage in certain individuals, you will note that the asbestos fibre content of these products is very small. I do not believe that a pulmonary fibrosis could develop from normal usage of these cements."

In Johns-Manville's chronology

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

Letter from Dr. K.W. Smith, 6/1/60, responding to Westinghouse Electric inquiry re 450 insulating cement. Dr. Smith states that he believes there is no pulmonary fibrosis risk from the normal usage of this cement. "While it is recognized that continued inhalation of asbestos fibers over a long period of time and sufficient concentration can cause some pulmonary damage in certain individuals," the asbestos content of these products is very small.