Saranac Laboratory Letter to Owens-Illinois on Synthetic Insulation (1943)

A one-page letter dated March 12, 1943, from Dr. Leroy U. Gardner, director of the Saranac Laboratory, to U.E. Bowes, director of research at the Owens-Illinois Glass Company, about the insulating material that became Kaylo. Gardner writes that what had been thought to be synthetic asbestos turned out to be chrysotile added as reinforcement, and that a mixture of quartz and asbestos "would certainly suggest that you have all the ingredients for a first class hazard." He proposes preliminary dust tests for no more than $300 and a larger animal study at $5,000 for the first year.

Why it matters

The letter shows that Owens-Illinois was warned of the hazard before Saranac ran a single test, and in the year Kaylo was introduced. The animal studies that followed confirmed in 1948 that Kaylo dust caused asbestosis. Owens-Illinois kept making and selling Kaylo without warnings, and Owens-Corning, which bought the product line in 1958, sold it until the early 1970s.