Therm-O-Flake L.B. Block

Product Description

Therm-O-Flake L.B. Block was a rigid thermal insulation product manufactured by A.P. Green Industries, a company historically associated with a broad range of refractory and insulating materials for industrial use. Produced between 1963 and 1972, this block-form insulation was engineered to withstand high-temperature environments commonly found in industrial facilities, manufacturing plants, and process piping systems.

The “L.B.” designation indicated a lightweight block composition, a product characteristic valued in industrial settings where thermal efficiency and ease of installation were both important considerations. Block insulation of this type was typically cut, shaped, and fitted around pipes, vessels, boilers, and other high-heat equipment. Its rigid format distinguished it from loose-fill or blanket insulation products, though all these product categories shared similar exposure risks when asbestos was incorporated into their composition.

A.P. Green Industries operated as a major supplier to heavy industry throughout much of the twentieth century, and its product lines reached facilities across a wide range of sectors, including steel mills, chemical plants, refineries, and power generation facilities. Therm-O-Flake L.B. Block was among the company’s offerings during a period when asbestos-containing insulation products were widely used throughout American industry.

Asbestos Content

Therm-O-Flake L.B. Block contained chrysotile asbestos as a component of its insulating matrix. Chrysotile, sometimes referred to as white asbestos, is a serpentine-form mineral fiber that was the most commonly used variety of asbestos in American industrial and construction products throughout the mid-twentieth century.

In block insulation products, chrysotile asbestos fibers served multiple functional purposes. The fibers contributed to the structural integrity of the rigid block, helped bind other insulating materials together, and improved the product’s resistance to mechanical stress and thermal cycling. These properties made asbestos a commercially attractive additive for manufacturers producing insulation intended to perform in demanding high-temperature environments.

Chrysotile fibers, like other asbestos mineral types, are recognized by the U.S. Environmental Protection Agency, the Occupational Safety and Health Administration (OSHA), and the National Institute for Occupational Safety and Health (NIOSH) as known human carcinogens. No safe level of occupational asbestos exposure has been established by these regulatory bodies. The incorporation of chrysotile into rigid insulation block products created conditions under which fiber release could occur during both manufacturing and installation activities.

How Workers Were Exposed

Industrial workers who handled, installed, or worked in proximity to Therm-O-Flake L.B. Block during its production years represent the primary population with documented exposure potential. The physical nature of rigid block insulation work created multiple pathways through which asbestos fibers could become airborne and be inhaled by workers.

During installation, blocks typically required cutting, sawing, or shaping to fit around pipe configurations, vessel contours, and equipment surfaces. These mechanical operations—performed without respiratory protection in most industrial settings of the 1960s and early 1970s—generated significant quantities of dust. When block insulation containing chrysotile asbestos was cut or abraded, individual fibers and fiber bundles were released into the surrounding air. Workers performing the cutting operations faced direct exposure, but so did other tradespeople and laborers working nearby on the same job site.

Removal and replacement activities presented equally significant exposure risks. Block insulation that had been in service for extended periods often became friable—brittle and easily crumbled—making fiber release during disturbance more pronounced than during original installation. Workers tasked with stripping old insulation from pipe systems or vessels could generate high concentrations of airborne dust in confined or poorly ventilated spaces.

Maintenance and repair activities on insulated pipe systems also created incidental exposure for industrial workers who were not themselves insulation specialists. Any work that required drilling through, cutting into, or mechanically disturbing insulation to access underlying pipe or equipment could release fibers. In large industrial facilities, this type of bystander or adjacent worker exposure could affect a wide range of occupational classifications.

Throughout the period of Therm-O-Flake L.B. Block’s production and use, OSHA’s current permissible exposure limits for asbestos did not yet exist in their modern form. Worker awareness of asbestos-related health risks was limited in many industrial environments, and personal protective equipment standards for asbestos work had not been established. Workers routinely performed insulation-related tasks in ordinary work clothing without respiratory protection.

The latency period associated with asbestos-related diseases—typically ranging from ten to fifty years between exposure and diagnosis—means that workers exposed to this product during its active years of use in the 1960s and into the 1970s may only be receiving diagnoses of asbestos-related illness in recent decades.

Diseases associated with occupational asbestos exposure include mesothelioma, a rare and aggressive cancer of the lining of the lungs, abdomen, or heart; asbestos-related lung cancer; asbestosis, a progressive fibrotic lung disease; and pleural disease including pleural plaques and pleural effusions.

Documented Trust Fund / Legal Options

Therm-O-Flake L.B. Block is a Tier 2 product for purposes of asbestos liability documentation. No dedicated asbestos bankruptcy trust fund has been established specifically to compensate claimants based on exposure to this product.

A.P. Green Industries did ultimately file for bankruptcy protection in connection with asbestos liabilities, and an A.P. Green asbestos trust was established through that bankruptcy process. However, litigation records document that claims involving specific A.P. Green products, including block insulation products from this era, have been pursued through civil litigation pathways rather than resolved exclusively through a single consolidated trust mechanism. Individuals seeking compensation should consult with qualified asbestos litigation attorneys to determine what trust fund eligibility, if any, may apply based on their specific exposure history and the particular products and premises involved.

In civil litigation, plaintiffs alleged that A.P. Green Industries and related entities knew or should have known about the hazards of asbestos-containing products and failed to adequately warn workers of those risks. Litigation records document claims asserting that the company continued to manufacture and sell asbestos-containing insulation products despite the availability of information regarding the health consequences of asbestos fiber inhalation.

Workers or surviving family members who believe they were exposed to Therm-O-Flake L.B. Block or similar A.P. Green insulation products should take the following steps:

• Document exposure history as specifically as possible, including facility names, dates of work, job titles, and any coworkers who may have witnessed the same conditions
• Preserve medical records documenting any diagnosis of mesothelioma, asbestos-related lung cancer, asbestosis, or pleural disease
• Consult an asbestos attorney experienced in both trust fund claims and civil litigation to evaluate all available legal remedies
• Act promptly, as statutes of limitations vary by state and are typically calculated from the date of diagnosis or the date a claimant knew or should have known of the connection between illness and asbestos exposure

Because many large industrial facilities used multiple asbestos-containing products simultaneously, claimants with exposure to Therm-O-Flake L.B. Block may also have viable claims against other manufacturers whose products were present at the same work sites. A comprehensive exposure history review with qualified legal counsel is the appropriate first step.