Permit Class Nuclear Attack Submarine (SSN-594) — Asbestos in the Cold War's First Modern SSN

The Permit class nuclear attack submarines — 14 boats commissioned between 1961 and 1968, hull numbers SSN-594 through SSN-612, also known as the Thresher class after the lead boat until the 1963 Thresher loss — established the teardrop hull form, single-screw propulsion, and deep-diving capability that defined US nuclear attack submarine design through the Cold War and beyond. The loss of USS Thresher (SSN-593) in April 1963 with all 129 aboard led to the SUBSAFE program that implemented rigorous safety systems throughout the submarine force. Permit class boats used the Westinghouse S5W pressurized water reactor driving a steam turbine on a single shaft for submerged propulsion. The Permit class boats were constructed at Electric Boat (Groton, Connecticut), Ingalls Shipbuilding, Mare Island Naval Shipyard, and Portsmouth Naval Shipyard during the early 1960s — a period when asbestos-containing secondary steam system insulation and interior construction materials were still used in submarine construction specifications. Nuclear-trained Machinist’s Mates and Electrician’s Mates serving aboard Permit class submarines worked in the confined engineroom and machinery spaces of boats that incorporated asbestos-containing materials in secondary steam system insulation and interior construction consistent with the early 1960s submarine construction period.

S5W Reactor Secondary Steam System Asbestos

Permit class submarines incorporated asbestos in secondary steam systems:

• Secondary steam system pipe insulation — the secondary side steam systems of the S5W reactor plant in Permit class submarines — steam generators, secondary steam distribution piping, turbine admission systems, and auxiliary steam systems — incorporated asbestos-containing thermal insulation on secondary steam piping and components consistent with the early 1960s submarine construction specifications. Nuclear-trained Machinist’s Mates standing engineering watches in the confined Permit class engineroom spaces worked in proximity to the asbestos-insulated secondary steam piping throughout their engineering watch standing in the submarine engineroom
• Propulsion turbine and machinery space construction — the propulsion turbines, reduction gears, and shaft systems in Permit class enginerooms were insulated and maintained in confined machinery spaces. Machinist’s Mates performing turbine and reduction gear maintenance in Permit class enginerooms worked in the confined asbestos-containing engineering spaces throughout their propulsion plant maintenance duties

Submarine Interior Construction Asbestos

Permit class boats incorporated asbestos in hull interior construction:

• Crew berthing and torpedo room construction — the crew berthing spaces, torpedo rooms, and living spaces in Permit class submarines constructed during the early 1960s incorporated asbestos-containing floor tile, insulation board, and pipe insulation in the submarine interior construction consistent with the construction specifications of the period. Crew members serving aboard Permit class submarines accumulated background asbestos exposure from the submarine interior construction materials in crew spaces, torpedo rooms, and living areas throughout their Permit class submarine assignments

VA Claims for Permit Class Veterans

VA presumptive service connection under 38 CFR § 3.309(d) covers asbestos exposure aboard Navy submarines. Machinist’s Mates, Electrician’s Mates, and crew members who served aboard Permit class nuclear attack submarines and have since been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer may qualify for VA disability benefits.

Source notes: equipment-manifest entries (where shown) are sourced from public-record BUSHIPS (Bureau of Ships) documentation, NARA archives, and the public asbestos litigation record. Manufacturer attributions link to documented asbestos-product histories on AsbestosIndex.com where available. Nothing on this page constitutes medical or legal advice.