Bureau of Ships to the Supervisor of Shipbuilding at Camden on Water-Repellent Amosite Felt (1943)

A one-page U.S. Navy memorandum of August 1943 from the Chief of the Bureau of Ships to the Supervisor of Shipbuilding, USN, at Camden, New Jersey, on "Insulation - Water Repellent Amosite for Cold Water Piping." It passes on comments from the Navy's Bureau of Medicine and Surgery, which had been sent a sample of the Amosite felt: a mineral wool insulation then being tested "will not present the occupational hazards incident to the use of water repellent amosite." Where amosite stayed in use, the medical bureau recommended approved respirators, yearly chest photofluorograms (small chest X-ray films) of exposed employees, and measurement of the dust in the air.

What it shows

The medical bureau added that local exhaust hoods were impracticable aboard naval vessels and suggested other ways of improving ventilation. Because the mineral wool would not be available "in the immediate future," the Bureau of Ships concluded that "it will be necessary to continue the use of the water repellent amosite felt," with the medical bureau's precautions. By 1943 the Navy's own physicians regarded amosite insulation work as an occupational hazard calling for respirators and chest X-rays, and the Navy kept using the material because no substitute was yet ready.