BOF Cote / BOF Patch / Anti-Erode Castable by Narco

Product Description

BOF Cote, BOF Patch, and Anti-Erode Castable were refractory products manufactured by Narco (National Refractories and Minerals Corporation) and produced between approximately 1963 and 1977. These products were engineered specifically for use in basic oxygen furnace (BOF) steelmaking operations, a process that became the dominant method of steel production in the United States during this era. Basic oxygen furnaces operate at extraordinarily high temperatures, subjecting their internal linings to severe thermal and mechanical stress. Refractory materials such as these were formulated to resist that stress, protecting the structural integrity of the furnace vessel and extending operational life between scheduled relining shutdowns.

BOF Cote and BOF Patch were applied as protective coatings and patching compounds to repair worn or damaged areas of furnace linings without requiring full relines. Anti-Erode Castable, as its name suggests, was a castable refractory material specifically designed to resist the erosive forces generated by molten steel, slag, and the intense oxygen-blowing process at the core of BOF steelmaking. Together, these three product lines served complementary roles in maintaining furnace performance during a period when American steel production was near its peak. Narco supplied refractory materials to steel mills, foundries, and heavy industrial facilities across the country, making these products a routine presence in high-temperature industrial environments throughout the 1960s and 1970s.

Asbestos Content

All three products—BOF Cote, BOF Patch, and Anti-Erode Castable—contained chrysotile asbestos as a formulation component. Chrysotile, sometimes referred to as white asbestos, is the most widely used form of asbestos in industrial applications and belongs to the serpentine mineral group. Its fine, flexible fibers provided refractory formulations with enhanced thermal stability, resistance to cracking under thermal cycling, and improved bonding characteristics in high-heat environments.

In refractory applications like these, chrysotile asbestos was typically blended with other refractory aggregates, binders, and mineral components. The asbestos content contributed to the material’s ability to withstand the punishing conditions inside a basic oxygen furnace, where temperatures routinely exceed 1,600 degrees Celsius. While chrysotile’s fiber structure differs from the amphibole asbestos varieties in certain respects, regulatory and medical authorities, including those overseeing OSHA standards and AHERA implementation, classify all commercial asbestos fiber types as hazardous carcinogens. Chrysotile has been associated in occupational health literature with asbestosis, lung cancer, and mesothelioma, particularly following prolonged or repeated inhalation exposure.

How Workers Were Exposed

Industrial workers employed in steel mills, foundries, and other facilities where BOF Cote, BOF Patch, and Anti-Erode Castable were used faced potential asbestos exposure through multiple routes during the products’ service life.

Mixing and Preparation: Anti-Erode Castable and similar formulations required on-site mixing with water or bonding agents before application. Workers who measured, poured, and mixed the dry castable material could disturb settled asbestos-containing dust, releasing respirable fibers into the breathing zone. In enclosed or poorly ventilated utility areas near furnace operations, fiber concentrations could accumulate rapidly.

Application: Applying BOF Cote and BOF Patch to furnace walls, trunnions, and other worn surfaces required direct handling of asbestos-containing material. Spray application, troweling, or gunning these products generated airborne particulate containing chrysotile fibers. Workers performing these tasks—whether Narco employees, steel mill maintenance personnel, or contracted refractory crews—worked in close proximity to the material throughout application.

Mechanical Disturbance During Furnace Maintenance: Refractory linings deteriorate over time under the stress of furnace operation, and routine maintenance required chipping, scarfing, or breaking out spent lining material before fresh refractory could be applied. These removal activities on previously applied asbestos-containing products were among the highest-exposure tasks, generating substantial quantities of fine dust containing both asbestos fibers and other breakdown products.

Ambient Exposure in the Mill Environment: Workers who were not directly involved in refractory application or maintenance—but who worked in the same building or general production area—could also be exposed to asbestos fibers carried through the air from adjacent work zones. In large steel mill bays where multiple operations occurred simultaneously, bystander exposure to refractory-related asbestos dust was a documented concern.

OSHA’s current permissible exposure limit (PEL) for asbestos is 0.1 fibers per cubic centimeter of air as an eight-hour time-weighted average, with an excursion limit of 1.0 f/cc over any thirty-minute period. Industrial hygiene data from the era in which these products were manufactured and applied routinely documented fiber concentrations that would far exceed those modern standards, often without the benefit of respiratory protection or engineering controls that later became mandatory.

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.

Corporate context: Formed in 1929 through the merger of several refractory companies including Queen’s Run, Crescent, and Eltra, among others. Owned by Eltra until 1979, then by Allied Signal (Allied) from 1979 to 1986, after which ownership transferred to banks and investors. Headquartered in Cleveland, Ohio.

Brand identification: Narco

Industries served: steel, iron.

North American Refractories Company (Narco) manufactured refractory materials used primarily in high-temperature industrial applications such as steel and iron processing. The company operated approximately eleven manufacturing facilities and a research center in Curwensville, Pennsylvania.