Nuclear-trained Machinist’s Mates (MM(N)) — Machinist’s Mates who completed the Navy’s nuclear power training pipeline at Naval Nuclear Power School and prototype reactor training — served aboard nuclear-powered attack submarines (SSN), fleet ballistic missile submarines (SSBN), aircraft carriers (CVN), and surface combatants (CGN) maintaining pressurized water reactor propulsion plants throughout the Cold War. Nuclear MMs operated and maintained the steam-generating reactor plant, secondary steam systems, propulsion turbines, steam-driven ship’s service generators, and associated auxiliary machinery in nuclear vessel engineering spaces. Nuclear-trained Machinist’s Mates working in nuclear submarine and carrier engine rooms accumulated background asbestos exposure from the asbestos-containing secondary steam system insulation and interior construction materials present in the engineering spaces of nuclear vessels commissioned during the transitional era before the Navy’s asbestos phase-out was substantially complete — particularly vessels commissioned in the 1960s and early 1970s when the nuclear shipbuilding program expanded dramatically and asbestos-containing materials remained in some construction specifications.

Nuclear Submarine Engineering Space Asbestos

Nuclear MMs in submarine engineering spaces accumulated background asbestos exposure:

  • Submarine secondary steam system pipe insulation — nuclear submarines commissioned in the 1960s and early 1970s — Permit class (SSN-594), Sturgeon class (SSN-637), and early Los Angeles class (SSN-688 series) — incorporated asbestos-containing insulation on secondary steam system piping in the engineroom, including steam generator secondary steam connections, throttle and turbine steam admission piping, and auxiliary steam system lines. Nuclear MMs standing engineering watches in the confined engineroom spaces of these submarines worked in proximity to the asbestos-insulated secondary steam piping throughout their watch standing
  • Submarine engine room interior construction — the interior construction of submarine enginerooms and machinery spaces aboard nuclear submarines of the 1960s and early 1970s incorporated asbestos-containing insulation and construction materials consistent with the construction specifications of the period. Nuclear MMs working in submarine enginerooms accumulated background asbestos exposure from the engineroom construction throughout their submarine engineering assignments

Nuclear Carrier Engineering Space Asbestos

Nuclear MMs aboard nuclear-powered carriers encountered asbestos in large engineering plants:

  • CVN secondary steam system insulation — nuclear-powered carriers — USS Enterprise (CVN-65) and the Nimitz class (CVN-68 through CVN-70, constructed 1968–1982) — incorporated asbestos-containing insulation in some secondary steam system applications consistent with the construction specifications in effect during each carrier’s construction period. Nuclear MMs working in carrier engineering spaces aboard Enterprise and early Nimitz class carriers worked in proximity to secondary steam system insulation throughout engineering watch standing
  • CGN nuclear cruiser engineering spaces — nuclear-powered guided missile cruisers — the Long Beach class (CGN-9), Bainbridge class (CGN-25), Truxtun class (CGN-35), California class (CGN-36 series), and Virginia class (CGN-38 series) — incorporated asbestos-containing secondary steam system insulation and interior construction materials in engineering spaces consistent with the construction periods of these Cold War-era nuclear cruisers. Nuclear MMs serving aboard nuclear cruisers worked in the asbestos-containing engineering spaces throughout their nuclear cruiser assignments

VA Claims for Nuclear-Trained Machinist’s Mates

VA presumptive service connection under 38 CFR § 3.309(d) covers asbestos exposure from Navy nuclear propulsion service. Nuclear-trained Machinist’s Mates who served aboard nuclear-powered submarines, carriers, or surface combatants and have since been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer may qualify for VA disability benefits.