Dr. Kenneth W. Smith to Mrs. Sylvan on a Child's Rash from Rock Wool Batts (1959)

A one-page letter of April 8, 1959, from Dr. Kenneth W. Smith, Johns-Manville's medical director, to Mrs. S. G. Sylvan of Long Island, New York, written at the request of J-M's sales organization after her son developed a skin rash from jumping on J-M Rock Wool batts. Smith explained that the mineral wool was made from limestone and blast furnace slag melted and formed into batts with a little linseed oil as a binder, and that the skin irritation it sometimes caused was mechanical, from very small particles of the wool, not allergic. He wrote that in many years of making the product J-M had seen no true allergic responses among its employees, so the boy's rash was "a mechanical rather than allergic response," and offered to answer the family doctor's questions.

In Johns-Manville's chronology

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

Letter from K.W. Smith of 4/8/59 to a Mrs. Sylvan regarding composition of Rock Wool batts. Smith advises that her son developed a mechanical skin irritation rather than allergic response after playing on the batts.