C. H. Jensen to E. C. Lindstrom on a Customer's Alarm at the Superex Caution Label (1965)

A one-page letter of February 9, 1965, from C. H. Jensen at J-M's Waukegan Industrial Insulations plant to E. C. Lindstrom at headquarters, reporting a verbal complaint from the Lindberg Engineering Company in Chicago about the caution labels on Superex cartons. Lindberg, the largest customer of J-M's Chicago distributor, Asbestos & Magnesia Materials Company, "has never been aware of the potential hazard of the continuous contact with the dust from this product and therefore has become exceedingly alarmed." Its first thought was to stop using the product; it was now evaluating silicated blocks that "would reduce or eliminate the dust problem."

What it shows

This early customer response to the label shows that at least one large user of J-M high-temperature insulation had not known of the dust hazard until the caution appeared on the carton in 1965. Jensen passed the complaint on and promised to report "further problems along this line."

In Johns-Manville's chronology

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

Letter from C.H. Jensen to E.C. Lindstrom, dated 2/9/65, relaying a verbal complaint from the Lindberg Engineering Company regarding caution labels on high temperature insulation products. Customer was previously unaware of a potential hazard from the dust of the product and reacted with alarm, and is considering discontinuing use of the product.