Pyrospray — Keene Corporation Spray-Applied Fireproofing

Product Description

Pyrospray was a spray-applied fireproofing material manufactured by Keene Corporation and sold primarily to commercial and industrial construction markets between 1963 and 1970. The product was designed to coat structural steel members — beams, columns, and decking — with a thick, insulating layer that would slow the transfer of heat during a fire and help steel-framed buildings meet fire resistance ratings required by building codes.

Spray-applied fireproofing became a standard feature of mid-century high-rise and industrial construction because it could be applied quickly over complex steel shapes at a fraction of the cost of traditional encasement methods. Pyrospray was among the products that made this application method commercially viable at scale. It was pneumatically sprayed onto bare steel by workers equipped with hoses, nozzles, and mixing equipment, creating a thick, fibrous coating that bonded directly to the metal surface.

Buildings constructed during the 1963–1970 production window — including office towers, schools, hospitals, manufacturing facilities, and public buildings — may retain Pyrospray fireproofing in place today. Where the material remains undisturbed, it may present an ongoing hazard if disturbed during renovation, demolition, or maintenance work.

Asbestos Content

Pyrospray contained chrysotile and/or amosite asbestos as a primary functional ingredient. Asbestos fibers were incorporated into spray-applied fireproofing formulations because they were heat-resistant, durable, lightweight, and capable of forming a fibrous matrix that adhered to structural steel and maintained its insulating properties under extreme temperatures.

Chrysotile (white asbestos) is the most commercially common asbestos variety and was widely used as a binder and insulating fiber in construction products throughout this period. Amosite (brown asbestos), mined primarily in South Africa, was favored in many fireproofing and insulation applications because of its particularly high heat resistance and long, stiff fibers. Products containing amosite are considered to present a serious health risk because amosite fibers — classified as an amphibole asbestos — are associated with elevated rates of mesothelioma, asbestosis, and lung cancer.

Federal regulation of asbestos in spray-applied fireproofing came through the Clean Air Act and, later, the Asbestos Hazard Emergency Response Act (AHERA), which established identification and management requirements for asbestos-containing materials in schools and other structures. OSHA’s asbestos standards, codified at 29 C.F.R. § 1926.1101 for construction work, identify spray-applied surfacing materials as among the highest-risk categories of asbestos-containing materials because of their tendency to release fibers when disturbed.

How Workers Were Exposed

Workers in multiple construction trades encountered Pyrospray during both original installation and subsequent building work. Exposure pathways were direct and, in many cases, continuous over the course of a workday.

Iron workers prepared and erected the structural steel framework to which Pyrospray was applied. In many construction sequences, fireproofing crews worked in close proximity to ironworkers or in the same floor areas, and residual dust from spray operations settled on surfaces throughout the work zone.

Construction laborers performed the physical mixing and spraying of Pyrospray material. Dry asbestos-containing powder was combined with water at the job site and fed through pneumatic spray equipment. Workers handling dry bags and operating mixing equipment were exposed to concentrated asbestos dust during the mixing process — before the material was wet — and again when overspray dried and was disturbed by foot traffic or equipment movement.

Lathers installed the metal lath and framing systems used to support spray-applied coatings in some applications. Their work required close contact with surfaces that had been coated or were being coated with Pyrospray.

Carpenters worked throughout construction sites during the same phases when fireproofing was being applied. They built formwork, installed blocking, and performed finishing work in areas where Pyrospray had been sprayed, often tracking through areas coated with dried fireproofing material or working near spray operations in progress.

Spray-applied fireproofing is particularly hazardous because the spraying process itself aerosolizes fine fibers. When wet material is forced through a nozzle under pressure, it creates a mist of asbestos-containing particles that can remain suspended in the air of an enclosed or partially enclosed floor. Workers without respiratory protection — standard practice throughout much of the 1963–1970 production period — inhaled these fibers directly.

Beyond the original installation period, workers who entered buildings years or decades later to perform renovation, mechanical work, or demolition also faced exposure when they disturbed intact but friable Pyrospray. Asbestos-containing spray fireproofing is classified as a friable material under AHERA, meaning it can be crumbled by hand pressure, releasing fibers into the air without the application of significant force.

Diseases associated with occupational asbestos exposure — including mesothelioma, lung cancer, asbestosis, and pleural disease — typically have latency periods of 20 to 50 years between first exposure and clinical diagnosis. Workers who handled Pyrospray during the 1960s may be receiving diagnoses today.

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.