Thermasil Pipe Covering — Keene Corporation

Thermasil was a thermal insulation product manufactured by Keene Corporation and sold primarily for industrial pipe-covering applications. Produced between 1956 and 1972, Thermasil contained chrysotile asbestos as a primary component of its insulating board and block formulations. Workers who handled, cut, or installed this product during those years — or who worked in facilities where it was used — faced documented exposure to airborne asbestos fibers. Mesothelioma, asbestosis, and lung cancer diagnoses traced to Thermasil exposure may be eligible for compensation through the Keene Corporation Asbestos Settlement Trust.

Product Description

Thermasil was manufactured by Keene Corporation as a rigid thermal insulation product designed for high-temperature pipe systems in industrial and powerhouse environments. The product was formed into insulating board and block configurations that could be cut to fit around pipes, fittings, and related infrastructure. Its primary markets included power generation facilities, chemical processing plants, shipyards, and heavy manufacturing operations — settings where maintaining thermal efficiency on steam and process piping was a critical operational requirement.

Keene Corporation was an industrial conglomerate with manufacturing interests across multiple sectors. Its building and industrial products divisions produced a range of asbestos-containing materials during the mid-twentieth century, with Thermasil representing one of the company’s pipe insulation lines. Production of Thermasil ran from 1956 through 1972, a period during which the use of asbestos in industrial insulation was widespread and largely unregulated. As regulatory scrutiny of asbestos intensified through the late 1970s and 1980s, liability exposure from Keene’s asbestos product lines grew substantially, eventually leading to the establishment of the Keene Corporation Asbestos Settlement Trust to compensate injured claimants.

Asbestos Content

Thermasil’s insulating board and block formulations contained chrysotile asbestos, the most commercially prevalent form of asbestos used in mid-century industrial products. Chrysotile fibers were incorporated into the product matrix to provide structural integrity under thermal stress, enhance fire resistance, and improve the material’s overall insulating performance at elevated temperatures common to industrial piping systems.

Chrysotile asbestos, while sometimes described as the “least hazardous” form of asbestos, is classified as a known human carcinogen by the International Agency for Research on Cancer (IARC) and is regulated as a hazardous material under OSHA standards and the Asbestos Hazard Emergency Response Act (AHERA). Prolonged or repeated inhalation of chrysotile fibers is associated with mesothelioma, asbestosis, and lung cancer. The rigid board and block format of Thermasil meant that cutting, shaping, and fitting the material to pipes was a routine and dust-generating task — activities that released respirable fiber into the breathing zone of workers performing the installation.

How Workers Were Exposed

Asbestos exposure from Thermasil was occupational and closely tied to the trades that installed and maintained industrial pipe systems. Four groups of workers faced particularly consistent contact with the product during its years of production and use.

Insulators (AWIU) were the primary trade responsible for applying Thermasil to piping systems. Members of the Asbestos Workers International Union (AWIU) — now part of the Heat and Frost Insulators and Allied Workers — cut Thermasil board and block to length, shaped it around pipe fittings, and secured it in place as part of routine insulation work. Each cut through the rigid material generated visible dust that contained respirable chrysotile fibers. In enclosed mechanical rooms or poorly ventilated powerhouse environments, fiber concentrations could accumulate significantly during a work shift.

Pipefitters frequently worked alongside insulators during the construction and maintenance of industrial piping systems. Even when not directly handling Thermasil, pipefitters operated in the same confined spaces where cutting and fitting activities were underway, creating bystander exposure conditions. During maintenance work, pipefitters often removed sections of existing Thermasil insulation to access valves or pipe connections, a disturbance process that released previously trapped fibers.

Powerhouse workers in steam-generating and power production facilities were among the most heavily exposed end-users of Thermasil. These workers lived and worked in environments where Thermasil-covered piping was present throughout the facility. Routine operations, equipment repairs, and the general deterioration of insulation over time meant that powerhouse workers faced ongoing ambient fiber exposure even without directly touching the insulation product.

Industrial maintenance workers in chemical plants, refineries, and heavy manufacturing operations encountered Thermasil during routine and emergency maintenance cycles. Removing, replacing, or disturbing aged Thermasil insulation was a common maintenance task, and workers in these settings often performed such work without the respiratory protection that OSHA standards now require. The latency period for asbestos-related diseases — which can span 20 to 50 years — means that maintenance workers who handled Thermasil in the 1960s and early 1970s may only now be receiving diagnoses.

In all of these occupational settings, the absence of effective engineering controls, adequate ventilation, and respiratory protective equipment during Thermasil’s production era contributed to meaningful and documented fiber exposures across these trades.

Documented Product Identification

The following details are drawn from public asbestos litigation records, manufacturer catalog pages, technical manuals, and corporate history materials. Each item reflects the product as documented in those sources.

Documented asbestos-use period: 1971-1972

Corporate context: Ehret Magnesia Manufacturing Company was acquired by Keene Corporation. Keene produced industrial and commercial insulation products containing asbestos.

Brand identification: KEENE, Ehret, FibreKote, Thermasil, Mono-Block, Mono-Spray, Super Powerhouse, No. 1 Plus

Documented asbestos components: pipe covering, asbestos felt, asbestos fibres, insulation, asbestos fiber.

Industries served: commercial construction, building industry, industrial insulation, military, US Coast Guard.

Naval / marine service: This manufacturer’s equipment is documented in connection with U.S. Navy and commercial-marine service.

Documented product lines:

  • Ehret 85% Magnesia Pipe Covering. 85% magnesia-based thermal pipe covering insulation. — asbestos components: pipe covering.
  • KEENE 8 oz Canvas Jackets 45# (1971-1972). Asphalt saturated asbestos felt jackets used for pipe and vessel insulation, compliant with Federal, Military, US Coast Guard and ASTM standards. — asbestos components: asbestos felt.
  • FibreKote (1971-1972). Coating/finishing material containing long asbestos fibres used in installation and construction of piping, vessels, and various insulation products. — asbestos components: asbestos fibres.
  • Thermasil Pipe and Block Insulation (1971-1972). Pipe and block thermal insulation installed with FibreKote asbestos-containing material. — asbestos components: insulation.
  • Metal Mesh Blanket Insulation (1971-1972). Blanket-style insulation used with FibreKote asbestos-containing finishing compound. — asbestos components: insulation.
  • Mono-Block Mineral Fiber Block Insulation (1971-1972). Mineral fiber block insulation product used with asbestos-containing FibreKote. — asbestos components: insulation.
  • Spun Felt Mineral Fiber Felt Insulation (1971-1972). Mineral fiber felt insulation applied with FibreKote. — asbestos components: insulation.
  • Mono-Spray, Spun and Monolithic Thermal Insulation (1971-1972). Spray-applied and monolithic thermal insulation products. — asbestos components: insulation.

Keene insulation products were documented as Federal, Military, and US Coast Guard compliant. FibreKote asbestos-containing finishing compound was used across multiple insulation product lines for pipe, vessel, and building applications.