Johns Manville Corporation, headquartered in Denver, Colorado, was the United States’ largest manufacturer of asbestos insulation products — dominating the market for pipe covering, block insulation, blanket insulation, and asbestos specialty products throughout the WWII and Cold War eras. Johns Manville (JM) asbestos pipe covering, block insulation, and blanket insulation was installed in virtually every steam-powered US Navy vessel built from the 1930s through the early 1970s — making Johns Manville the most significant single manufacturer in the history of Navy asbestos exposure.

Johns Manville Asbestos Products in Navy Applications

The full range of Johns Manville asbestos insulation products appeared in Navy applications:

  • Pipe covering — the flagship Johns Manville asbestos pipe covering product in the industry-standard 85% magnesia and calcium silicate formulations was used throughout Navy steam plant piping systems on every vessel class from WWII through the 1970s. JM pipe covering was applied to main steam piping, auxiliary steam piping, feedwater piping, and exhaust steam piping throughout the engineering spaces and hotel steam distribution of Navy surface ships and submarines
  • Block insulation — Johns Manville asbestos block insulation applied to boiler casings, turbine casings, and irregular large surfaces used the same high-asbestos fiber content formulations in a rigid block form, with blocks cut and fitted to complex equipment shapes by shipyard insulators and ship’s company personnel
  • Blanket insulation — Johns Manville asbestos blanket products used for equipment insulation on valves, expansion joints, and irregular surface applications throughout the ship’s steam plant
  • 85% magnesia insulation — the Johns Manville brand version of the 85% magnesia pipe and equipment insulation specification that was the Navy standard for high-temperature steam service applications throughout the WWII and Cold War era

Dominant Market Position

Johns Manville’s dominance of the naval insulation market meant that JM products were not merely present in Navy ships — they were ubiquitous:

  • Navy supply specifications for pipe covering and block insulation frequently referenced JM or JM-equivalent as the standard, making JM the default supplier and setting the asbestos content standard for the industry
  • Shipyard insulation contractors applying insulation during ship construction and overhaul worked primarily with Johns Manville products, with JM pipe covering being the stock material for the Navy’s naval shipyard insulation contractors throughout the primary asbestos era

Asbestos Trust

Johns Manville filed for bankruptcy in 1982 due to asbestos liability — the first major industrial bankruptcy driven by asbestos claims — creating the Manville Personal Injury Settlement Trust (now the Manville Trust). The Manville Trust is one of the largest asbestos trust funds, with legal recourse available for victims of Johns Manville asbestos product exposure including Navy veterans.

VA Claims for Veterans Exposed to Johns Manville Products

VA evaluates asbestos-related disability claims on a case-by-case basis. Veterans generally need evidence of in-service asbestos exposure, a current asbestos-related diagnosis, and a medical link between them. Engineering ratings and other personnel who were exposed to Johns Manville asbestos insulation products throughout Navy service and have since been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer may qualify for both VA disability benefits and Manville Trust claims.