CM Gun Mix

Product Description

CM Gun Mix was a gunnable refractory and insulating castable material manufactured by Narco (North American Refractories Company) between 1963 and 1973. The product was designed for pneumatic application — meaning it was mixed with water and then sprayed or “gunned” onto surfaces using specialized equipment — making it practical for lining furnaces, kilns, boilers, and high-temperature industrial equipment where precise, durable thermal insulation was required.

Narco was a well-established name in the refractory products industry, supplying materials to steel mills, foundries, petrochemical facilities, glass manufacturing plants, and other heavy industries that relied on heat-resistant materials to protect equipment and maintain operational efficiency. CM Gun Mix was part of a broader product line intended to provide rapid application of insulating material in environments where hand-packing or troweling was impractical or too time-consuming.

The “gun mix” designation referred directly to the application method: the dry material was loaded into a gunning machine, combined with water at the nozzle, and projected at high velocity onto walls, floors, ceilings, or pipe surfaces inside industrial structures. This method allowed crews to cover large surface areas relatively quickly, but it also generated substantial airborne dust — a characteristic that would later prove significant in asbestos exposure litigation.

CM Gun Mix was used across the productive lifespan of the product from 1963 through 1973, a period during which regulatory oversight of asbestos in industrial workplaces was limited and worker awareness of the associated health risks was minimal.

Asbestos Content

CM Gun Mix contained chrysotile asbestos as a component of its formulation. Chrysotile, sometimes referred to as “white asbestos,” is a serpentine mineral fiber that was widely used in refractory and insulating materials throughout the mid-twentieth century because of its heat resistance, tensile strength, and ability to bind other materials together during application and curing.

Although chrysotile has a different fiber structure than amphibole forms of asbestos such as amosite or crocidolite, decades of epidemiological research and regulatory findings have established that chrysotile exposure is associated with asbestosis, lung cancer, and mesothelioma. OSHA’s current permissible exposure limit for asbestos — 0.1 fibers per cubic centimeter as an eight-hour time-weighted average — applies equally to all regulated asbestos fiber types, including chrysotile.

The presence of asbestos in gunnable refractory mixes like CM Gun Mix served a functional purpose: fibers helped reinforce the applied material, reduced cracking during the curing process, and contributed to the thermal stability of the finished lining. However, these same properties meant that the product released asbestos fibers during mixing, during pneumatic application, and during any subsequent disturbance, repair, or removal of the cured material.

How Workers Were Exposed

Industrial workers who handled, applied, or worked in proximity to CM Gun Mix during its production years faced potential asbestos fiber exposure through several distinct pathways.

Mixing and loading operations presented a primary exposure point. Before being fed into the gunning machine, CM Gun Mix existed as a dry powder. Opening bags, pouring the material into hoppers, and stirring or blending the mix could release substantial quantities of airborne dust containing chrysotile fibers. Workers performing these tasks without respiratory protection faced direct inhalation risk.

Pneumatic gunning application was the defining exposure scenario associated with this product. When the material was sprayed onto surfaces at high velocity, it produced a visible cloud of mist and particulate. Overspray — the portion of the material that did not adhere to the target surface — settled throughout the work area and became airborne again when disturbed. Workers operating the gun, as well as those performing other tasks in the same space, could inhale fibers throughout the duration of an application job.

Maintenance, repair, and demolition activities created secondary exposure opportunities. Once CM Gun Mix had cured onto furnace walls, kilns, or pipe surfaces, it remained in place until repairs or equipment overhauls were required. Breaking out or grinding cured refractory material released embedded asbestos fibers. Workers involved in relining operations — who may have had no involvement in the original application — faced exposure during the removal of older material.

General industrial facility exposure affected workers throughout plants where CM Gun Mix had been applied. Settled asbestos-containing dust on equipment surfaces, catwalks, and floors could be re-entrained in air by foot traffic, air movement, or routine maintenance activities, creating ongoing low-level exposure for workers who never directly handled the product.

Industrial workers generally, including furnace operators, refractory installers, maintenance mechanics, boilermakers, and millwrights employed at facilities where Narco products were in use, are among those identified in litigation records as potentially exposed to CM Gun Mix.

CM Gun Mix is a Tier 2 — Litigated product. There is no established asbestos bankruptcy trust fund associated with Narco specifically designated to compensate CM Gun Mix claimants at this time. Individuals seeking compensation for asbestos-related illness linked to this product have pursued remedies through the civil court system.

Litigation records document claims brought against Narco and related defendants by industrial workers alleging that exposure to asbestos-containing refractory and gunning products, including CM Gun Mix, caused serious illness including mesothelioma, asbestosis, and lung cancer. Plaintiffs alleged that Narco and other parties in the chain of product distribution knew or should have known about the hazards associated with asbestos-containing materials and failed to provide adequate warnings to workers who used or were exposed to these products.

Plaintiffs alleged in documented cases that the dusty nature of gunnable products made them particularly hazardous and that the absence of health warnings on product packaging and in workplace safety communications left workers without meaningful opportunity to protect themselves.

If you or a family member worked in an industrial facility between 1963 and 1973 where CM Gun Mix was applied — or where older refractory linings were disturbed during maintenance or demolition — and have since been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer, legal options may remain available. Because mesothelioma and other asbestos diseases have long latency periods, diagnoses frequently occur decades after the original exposure.

Consulting with an attorney who specializes in asbestos litigation is the appropriate first step. Qualified counsel can review employment history, identify all potential exposure products and defendants, determine applicable statutes of limitations in the relevant jurisdiction, and advise on whether civil litigation is the most appropriate path forward. Documentation such as employment records, union membership records, Social Security earnings histories, and co-worker testimony can all support the establishment of product-specific exposure claims.

This article is provided for informational purposes only and does not constitute legal advice. Consult a qualified asbestos attorney regarding individual circumstances.