Arthur L. Fisk Jr. to Guy H. Haskins Jr. on Rock Wool Insulation (1959)

A two-page letter of April 27, 1959, from Arthur L. Fisk, Jr., Johns-Manville's assistant general attorney, to Guy H. Haskins, Jr., of the law firm Skeffington, Haskins & Skeffington in Bloomfield, New Jersey, who had asked about J-M's rock wool insulation in a matter headed "Re: John Coe." Fisk explained that the wool was made from limestone and blast furnace slag and wrote: "To the best of our knowledge our rock wool does not contain any free silica or asbestos, nor does it produce any form of pulmonary fibrosis or pneumoconiosis. We have no knowledge of claims for pneumoconiosis associated with the use of this material."

What it shows

Fisk enclosed a paper by L. T. Fairhall and others, "Rock Wool in Relation to Health," summarized a 1945 Indiana study that found no silicosis or lung fibrosis in 84 mineral wool workers, and described a survey by the Industrial Health Section of the Metropolitan Life Insurance Company at a J-M mineral wool plant. That survey X-rayed 400 employees, most with more than ten years in the work, found no silicosis or abnormal lung fibrosis, and led Metropolitan Life to advise that mineral wool was "innocuous from the point of lung fibrosis." The letter does not say who John Coe was.

In Johns-Manville's chronology

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

Letter from Arthur L. Fisk, Jr. dated 4/27/59 to Guy H. Haskins. Jr. (re: John Coe). Advised that; "To the best of our knowledge our rock wool does not contain any free silica or asbestos, nor does it produce any form of pulmonary fibrosis or pneumoconiosis.