Gas Turbine Systems Technicians Mechanical — GSMs — operated and maintained the gas turbine engines, reduction gears, controllable pitch propellers, and associated propulsion machinery aboard Navy gas turbine-powered surface ships. GSM billets were primarily aboard Spruance class (DD-963) destroyers, Oliver Hazard Perry class (FFG-7) frigates, and Ticonderoga class (CG-47) Aegis cruisers — the gas turbine surface combatants that replaced the previous generation of steam-powered destroyers and cruisers beginning in the 1970s.

Gas Turbine Exhaust System and Asbestos

Gas turbine-powered ships used thermal insulation on exhaust system components, with asbestos present in earlier-production ships:

  • Gas turbine exhaust uptake insulation — the hot exhaust ducting carrying combustion gases from the LM2500 gas turbines through the ship’s uptake system to the exhaust stacks used thermal insulation on the hot duct surfaces. In the earliest gas turbine ships — Spruance class destroyers commissioned from 1975 and Perry class frigates commissioned from 1977 — the exhaust uptake insulation specifications included asbestos-containing insulation materials in some construction areas before the Navy’s phase-down of asbestos reached gas turbine exhaust system specifications
  • Engine module hot section access — GSMs performing maintenance on the LM2500 engine module’s hot section — turbine inlet and exhaust transition sections — worked in proximity to the high-temperature section of the engine with thermal insulation materials used in early engine module designs

Auxiliary Boiler and Steam System

Spruance class destroyers and some Perry class frigates carried auxiliary boilers for hotel steam and emergency propulsion:

  • Auxiliary boiler maintenance — GSMs on ships equipped with auxiliary boilers maintained these boilers in addition to the gas turbines. Auxiliary boilers on early Spruance class ships used asbestos-insulated boiler components in the 1975-era construction consistent with the transitional period when the auxiliary boiler specifications still included asbestos
  • Hotel steam distribution — the auxiliary steam distribution system serving laundry, galley, and heating loads on gas turbine ships with auxiliary boilers used asbestos-insulated steam supply piping in early-construction ships

Comparison to Predecessor Steam Engineering Ratings

GSMs working on early gas turbine ships had substantially lower asbestos exposure than their predecessors — BTs and MMs — on steam-powered destroyers and cruisers:

  • The shift to gas turbine propulsion dramatically reduced the asbestos exposure profile of Navy surface ship engineering ratings, with gas turbine engineering spaces lacking the extensive asbestos-insulated boilers and steam piping of steam plant ships
  • Early-period GSMs on the first Spruance and Perry class ships (1975-1984) have a higher asbestos claim than later-period GSMs as the exhaust system and auxiliary boiler specifications completed the asbestos phase-down

VA Claims for GSM Veterans

VA presumptive service connection under 38 CFR § 3.309(d) covers asbestos exposure from gas turbine and auxiliary boiler maintenance in Navy service. Gas Turbine Systems Technicians who served in engineering billets aboard early Spruance class and Perry class ships and have since been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer may qualify for VA disability benefits.