Monospray — Keene Corporation Asbestos Spray Fireproofing

Product Description

Monospray was a spray-applied fireproofing product manufactured by Keene Corporation and sold primarily between 1963 and 1970. The product was designed to meet fire-resistance requirements for structural steel and metal decking in commercial and industrial construction, where building codes and insurance standards demanded that load-bearing steel be protected against heat-induced failure. Spray-applied fireproofing of this type became a standard feature of high-rise buildings, warehouses, schools, hospitals, and other large structures constructed during the postwar building boom.

Keene Corporation marketed Monospray as a cost-effective alternative to traditional fireproofing methods such as encasement in concrete or application of ceramic tile. Like many spray fireproofing products of its era, Monospray was applied directly to structural members using pneumatic spray equipment, allowing crews to coat large quantities of steel quickly and at relatively low cost. This efficiency made the product attractive to general contractors working under tight construction schedules, and it was used extensively across the United States during the 1960s.

The product sat within a broader category of spray-applied fireproofing materials that regulators and researchers would later identify as a primary source of asbestos exposure in the construction trades. Buildings constructed with Monospray and similar products represent a continuing legacy hazard, because damaged or deteriorating spray fireproofing can release asbestos fibers decades after original installation.

Asbestos Content

Monospray contained chrysotile asbestos as a primary component. Chrysotile, sometimes called white asbestos, was widely used in spray fireproofing formulations during the 1960s because its fibrous structure provided both thermal insulation and tensile reinforcement within the sprayed matrix. When mixed with binders and other ingredients and applied by spray equipment, chrysotile asbestos bonded to the surface of structural steel and metal decking, forming a textured, insulating coating.

The use of asbestos in spray-applied fireproofing was not incidental — the mineral was integral to the product’s performance characteristics. Keene Corporation’s use of chrysotile in Monospray was consistent with industry practice during the period of manufacture, and the product was sold and applied at a time when the health consequences of chrysotile fiber inhalation were known within scientific and industrial hygiene communities but were not routinely communicated to the workers handling these materials on job sites.

The U.S. Environmental Protection Agency later identified spray-applied asbestos fireproofing as one of the most hazardous asbestos-containing materials in buildings, in part because it is a friable material — meaning it can be crumbled by hand pressure — and releases fibers readily when disturbed. AHERA regulations governing asbestos inspection and management in school buildings specifically address friable spray-applied surfacing materials, and the standards developed under AHERA reflect the recognized hazard associated with products like Monospray.

How Workers Were Exposed

Workers in multiple construction trades faced direct exposure to Monospray during its manufacture, application, and in subsequent building work where the installed product was disturbed.

Iron workers who erected structural steel frames and metal decking frequently worked in close proximity to spray fireproofing operations. On active construction sites, spray application often occurred while other trades were still working in the same areas, and iron workers handling freshly erected steel sometimes worked directly alongside or beneath spray crews.

Construction laborers were among the most directly exposed. Laborers performed general support work on spray fireproofing crews, including mixing materials, moving equipment, and cleaning up overspray. They worked at close range during application and were exposed to the visible dust and fiber clouds generated when Monospray was sprayed onto structural surfaces.

Lathers installed the metal furring, channels, and lath systems used to support plaster and drywall assemblies throughout the same structures receiving spray fireproofing. Their work required them to drill, cut, and fasten metal components in areas where Monospray had been applied or was actively being applied, generating additional fiber release.

Building maintenance workers faced a distinct and ongoing exposure risk that extended well beyond the original construction period. Workers performing routine maintenance, repairs, or renovations in buildings where Monospray was installed could disturb the spray-applied coating during drilling, cutting, pipe work, or any activity that required penetrating or disturbing the ceiling or structural steel assembly. Because Monospray is a friable material, even incidental contact during maintenance activities could release chrysotile fibers into the breathing zone of workers who had no awareness that asbestos was present.

Exposure in all of these categories was typically uncontrolled during the years Monospray was produced and applied. Respiratory protection was not standard practice, and industrial hygiene procedures specific to asbestos were not required on construction sites until OSHA asbestos standards were developed in subsequent decades.

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.