Therm-O-Flake L.B. Block — A.P. Green Industries

Product Description

Therm-O-Flake L.B. Block was a lightweight refractory block insulation manufactured by A.P. Green Industries and produced from approximately 1963 through 1972. Designed for high-temperature industrial applications, the product was marketed primarily for use in industrial furnaces, boilers, kilns, and large-diameter pipe insulation systems where both thermal performance and structural stability were required.

The “L.B.” designation in the product name referenced its lightweight block construction — a design feature intended to reduce the overall load burden on industrial structures while still delivering the high-temperature insulating properties that refractory applications demanded. This lightweight formulation made the block particularly attractive for installations where conventional dense refractory materials were impractical due to weight constraints or difficult access, including overhead furnace linings and complex pipe-covering configurations in power generation, petrochemical, and heavy manufacturing facilities.

A.P. Green Industries was one of the most significant refractory and insulation manufacturers in the United States during the mid-twentieth century. The company supplied products to a broad range of industrial sectors, including steel mills, oil refineries, chemical plants, and power stations. Therm-O-Flake L.B. Block was part of the company’s broader catalog of asbestos-containing refractory and insulation products produced during a period when asbestos was widely incorporated into thermal insulation materials as a standard industry practice.

Asbestos Content

Therm-O-Flake L.B. Block contained chrysotile asbestos as a reinforcing fiber within its lightweight block matrix. Chrysotile, the most commonly used variety of commercial asbestos, was incorporated into the product’s formulation to provide tensile reinforcement, improve resistance to thermal shock, and extend the structural life of the block under repeated high-temperature cycling.

In refractory and insulation block products of this era, chrysotile fibers were typically blended with calcium silicate, diatomaceous earth, or similar binder materials before being formed and cured into block shapes. The asbestos fiber content served a critical manufacturing function: it held the lightweight matrix together under the mechanical stresses associated with industrial heat applications, preventing cracking and crumbling that would otherwise occur in non-reinforced low-density insulating materials.

Documentation associated with A.P. Green Industries’ product lines — including materials reviewed in connection with asbestos litigation and the company’s subsequent bankruptcy proceedings — confirms the use of asbestos-containing formulations in refractory and pipe-covering products manufactured during the 1963–1972 period in which Therm-O-Flake L.B. Block was produced.

How Workers Were Exposed

Workers across multiple skilled trades encountered Therm-O-Flake L.B. Block during installation, maintenance, and removal operations at industrial facilities throughout the product’s years in service. Asbestos fiber release was a documented hazard during virtually every phase of hands-on work with asbestos-containing block insulation of this type.

Insulators who handled Therm-O-Flake L.B. Block on a routine basis faced the highest cumulative exposure risk. Cutting blocks to fit around pipe flanges, vessels, or irregular surfaces — using hand saws, power saws, or grinders — generated substantial quantities of airborne dust containing respirable chrysotile fibers. Fitting and trimming operations were frequently performed in enclosed or poorly ventilated industrial spaces where dust could accumulate without adequate dispersal.

Refractory installers worked directly with the product during furnace lining, kiln construction, and boiler insulation projects. Mixing mortar, setting blocks, and grinding surfaces to achieve proper fits were all tasks that disturbed the asbestos-containing material and released fibers into the breathing zone of workers performing the work.

Boilermakers encountered Therm-O-Flake L.B. Block and similar refractory products during installation work on boilers and pressure vessels, as well as during maintenance shutdowns and repairs. Removing deteriorated or damaged insulation block during overhaul work — often without respiratory protection or knowledge of the material’s hazardous content — represented a significant secondary exposure pathway.

Industrial maintenance workers at steel mills, power plants, refineries, and chemical processing facilities were frequently exposed to Therm-O-Flake L.B. Block during routine maintenance operations, equipment repairs, and annual plant turnarounds. Because the product remained in service in many industrial facilities well beyond its production date, maintenance workers continued to encounter aging and friable asbestos-containing block insulation into the 1980s and in some cases beyond.

Bystander exposure was also a documented concern. Workers in adjacent trades — pipefitters, millwrights, welders, and general laborers — who worked in the same areas as insulation and refractory operations could inhale asbestos fibers released by others handling Therm-O-Flake L.B. Block, even without directly touching the product themselves.

The latency period for asbestos-related diseases, including mesothelioma, asbestosis, and asbestos-related lung cancer, typically ranges from 20 to 50 years following initial exposure. This means that workers exposed to Therm-O-Flake L.B. Block during its production years may only now be receiving diagnoses of asbestos-related illness.

A.P. Green Industries filed for Chapter 11 bankruptcy protection in 2002, primarily as a result of substantial asbestos-related litigation stemming from its decades of manufacturing asbestos-containing refractory and insulation products. As part of the bankruptcy reorganization process, the A.P. Green Industries Asbestos Settlement Trust was established to compensate individuals harmed by exposure to A.P. Green products, including Therm-O-Flake L.B. Block.

Trust Eligibility

Individuals who were diagnosed with a qualifying asbestos-related disease and who can document occupational exposure to Therm-O-Flake L.B. Block or other A.P. Green asbestos-containing products may be eligible to file a claim with the A.P. Green Industries Asbestos Settlement Trust. Eligible claimants typically include workers with direct exposure, as well as, in some cases, household members who experienced secondary exposure through contaminated work clothing.

Qualifying Disease Categories

The A.P. Green Industries Asbestos Settlement Trust generally recognizes claims arising from the following disease categories, subject to trust-specific medical and exposure criteria:

  • Mesothelioma (pleural, peritoneal, and pericardial)
  • Lung cancer with documented asbestos exposure history
  • Asbestosis and other non-malignant asbestos-related conditions
  • Other asbestos-related cancers as defined in the trust’s disease level criteria

Filing Considerations

Claimants filing with the A.P. Green Industries Asbestos Settlement Trust are required to provide medical documentation confirming diagnosis, as well as evidence establishing exposure to A.P. Green products. Product identification through employment records, union records, co-worker affidavits, or facility records naming Therm-O-Flake L.B. Block strengthens a claim. Because trust claim deadlines and payment percentages are subject to change based on trust solvency and claim volume, individuals or their legal representatives should confirm current filing requirements directly with the trust or qualified asbestos litigation counsel.

Individuals who were exposed to Therm-O-Flake L.B. Block at facilities where other manufacturers’ asbestos products were also present may be eligible to file claims with multiple asbestos trusts simultaneously, depending on the products and companies involved. An attorney experienced in asbestos trust fund claims can assist in identifying all potentially applicable trusts.