George Smolak of the J-M Research Center to R. F. Orth on Amosite Fiber in Asbestos-Cement Pipe (1956)

A one-page memo of June 1, 1956, from George Smolak at Johns-Manville's Research Center to R. F. Orth at headquarters, comparing Amosite with blue (crocidolite) fiber in asbestos-cement pipe. He reported that amosite gave 32 to 56 per cent less strength at the same density, though it filtered better, and gave tensile strengths for crocidolite, amosite and chrysotile. If the manufacturing department wanted amosite in the pipe formulas, he wrote, "please, please do not give your O.K. in pressure pipe until we have discussed it at greater length because this move may prove tragic."

What it shows

The memo is about product strength and cost, not health: the "tragic" outcome Smolak feared was weaker pressure pipe. It shows J-M weighing amosite and crocidolite as interchangeable raw materials for asbestos-cement pipe in 1956, on grounds of strength, filtering and price.