Square D Company, headquartered in Milwaukee, Wisconsin, was one of the largest manufacturers of electrical distribution and control equipment in the United States, supplying switchgear, circuit breakers, motor starters, and electrical distribution panelboards to commercial, industrial, and military customers throughout the mid-twentieth century. Square D supplied the US Navy with electrical distribution equipment for shipboard power distribution systems during the WWII and Cold War era. Like other manufacturers of electrical switching equipment of the period, Square D’s circuit breakers and switchgear used asbestos-containing arc chute materials to quench the high-temperature electrical arcs produced during circuit interruption. Navy Electrician’s Mates performing maintenance, testing, and repair of Square D electrical equipment aboard ships accumulated asbestos exposure from the arc chute and insulation materials in these switchgear products.

Asbestos in Square D Naval Products

Square D’s electrical distribution equipment incorporated asbestos:

  • Circuit breaker arc chute materials — Square D circuit breakers used asbestos-containing arc chute assemblies that provided the heat-resistant medium for arc extinction during electrical fault interruption. The asbestos fiber in these components provided the thermal resistance required for arc extinction in the compact circuit breaker construction. Electrician’s Mates removing Square D circuit breakers during shipboard electrical maintenance encountered asbestos-containing arc chute materials that released asbestos fiber when the breakers were removed and disassembled for inspection
  • Switchgear panel insulation — the electrical insulation used in Square D switchgear bus work and panel assembly construction incorporated asbestos-containing materials for high-temperature electrical insulation in the switchgear construction. Navy Electrician’s Mates working within switchgear panels during maintenance and fault investigation worked in proximity to these asbestos-containing insulation materials
  • Motor starter and contactor arc chutes — Square D motor starters and contactors used in motor control centers aboard Navy ships used asbestos-containing arc chute materials in the starter and contactor switching contacts, with Electrician’s Mates performing motor control maintenance encountering asbestos-containing arc chute materials during starter and contactor maintenance operations

Square D equipment appeared in Navy ship electrical distribution:

  • Shipboard power distribution panels — Navy surface ships and submarines used electrical distribution panelboards and circuit breakers from Square D and competitor manufacturers in ship service power distribution systems serving ship’s service loads, lighting, and auxiliary equipment throughout the vessel

VA Claims for Veterans Exposed to Square D Products

VA presumptive service connection under 38 CFR § 3.309(d) covers asbestos exposure from electrical equipment maintenance in Navy engineering spaces. Electrician’s Mates who performed switchgear maintenance using Square D equipment with asbestos arc chute materials and have since been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer may qualify for VA disability benefits.