Number One Plus Cement

Manufacturer: Keene Corporation Product Category: Pipe Insulation Asbestos Content: Chrysotile Asbestos Years Produced: 1938–1971

Product Description

Number One Plus Cement was an asbestos-containing pipe insulation cement manufactured by Keene Corporation during the mid-twentieth century. The product was designed for use in industrial settings where thermal insulation and protection of piping systems were essential operational requirements. As a cement-form insulation product, it was applied to pipe surfaces to reduce heat transfer, protect infrastructure from temperature fluctuations, and provide a durable coating capable of withstanding the demanding conditions found in heavy industrial environments.

Keene Corporation, originally founded under a different corporate identity and reorganized through multiple acquisitions and restructurings over the decades, produced a range of building and industrial materials throughout the twentieth century. Number One Plus Cement represented one of the company’s offerings in the industrial insulation market, a segment that relied heavily on asbestos-containing materials during the product’s years of production. The cement was marketed to and used within industrial facilities including power plants, refineries, chemical processing plants, and manufacturing operations where extensive pipe networks required insulation.

The product remained in production from 1938 through 1971, a period during which the use of asbestos in industrial insulation was standard practice across the United States. Industry-wide reliance on asbestos during this era meant that products like Number One Plus Cement were widely distributed and applied across countless worksites, contributing to significant and lasting occupational exposure for workers in numerous trades.

Asbestos Content

Number One Plus Cement contained chrysotile asbestos, the most commercially prevalent form of asbestos used in industrial products throughout the twentieth century. Chrysotile, sometimes referred to as white asbestos, is a serpentine mineral fiber that was valued for its flexibility, tensile strength, and resistance to heat—properties that made it a natural fit for pipe insulation applications.

In cement-form insulation products, chrysotile fibers were typically blended with binding agents and other materials to create a workable paste or mortar-like compound. Once applied to pipe surfaces and allowed to cure, the cement formed a hardened insulating layer. The asbestos fibers within this matrix provided structural reinforcement and enhanced the product’s thermal insulating properties.

While chrysotile fibers are generally regarded as having different physical characteristics than amphibole asbestos varieties such as crocidolite or amosite, regulatory bodies including the U.S. Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) classify all forms of asbestos as known human carcinogens. There is no established safe level of occupational exposure to chrysotile asbestos, and the fiber type has been definitively linked to mesothelioma, lung cancer, asbestosis, and other serious respiratory diseases through decades of epidemiological and clinical research.

How Workers Were Exposed

Industrial workers who handled, applied, or worked in proximity to Number One Plus Cement were at risk of inhaling airborne asbestos fibers during multiple stages of the product’s use. Exposure pathways were numerous and reflected the realities of industrial worksites during the mid-twentieth century, where respiratory protective equipment was rarely required, inadequate when provided, and generally not enforced by employers or manufacturers.

The primary exposure scenario involved the mixing and application of the cement. Workers who prepared the product—combining it with water or other materials to achieve a workable consistency—were exposed to asbestos dust released during the mixing process. The agitation of dry cement material could release substantial quantities of airborne chrysotile fibers into the breathing zone of workers performing or assisting with this task.

Application workers who troweled, brushed, or otherwise spread the cement onto pipe surfaces also faced direct exposure. As the material was worked onto pipe exteriors, fibers could be dislodged and become airborne. In enclosed industrial settings with limited ventilation, these fibers could accumulate to elevated concentrations and persist in the air for extended periods.

Maintenance and renovation activities posed additional exposure risks throughout the lifespan of installed Number One Plus Cement. When existing insulation cement required repair, removal, or replacement, the hardened material was often broken apart, chipped, or ground away—activities that generated significant quantities of asbestos-containing dust. Workers performing such tasks, as well as those working in adjacent areas of a facility, could be exposed to high concentrations of released fibers.

Bystander exposure was also a recognized risk in industrial settings. Workers performing unrelated tasks in areas where pipe insulation work was underway—machinists, electricians, laborers, and others—could inhale fibers simply by virtue of sharing a workspace with those directly handling asbestos-containing products.

Documented Trust Fund / Legal Options

Number One Plus Cement is classified as a Tier 2 — Litigated product. There is no dedicated asbestos bankruptcy trust fund through which claims related to this product may be filed. Individuals seeking compensation for asbestos-related illnesses associated with exposure to Number One Plus Cement must pursue their claims through civil litigation in the tort system.

Litigation records document that Keene Corporation faced extensive asbestos-related litigation over many decades due to its manufacture of asbestos-containing products including pipe insulation cements. Plaintiffs alleged that Keene Corporation knew or should have known about the hazards associated with asbestos exposure and failed to adequately warn workers of those dangers. Plaintiffs further alleged that the company continued manufacturing and marketing asbestos-containing products despite the availability of information linking asbestos exposure to serious disease.

Litigation records document that claims involving Keene Corporation products were among the substantial volume of asbestos cases that moved through U.S. courts beginning in the 1970s and accelerating through the 1980s and 1990s. The range of diseases alleged in connection with occupational exposure to Keene products included mesothelioma, lung cancer, asbestosis, and pleural disease.

Because no active trust fund exists for this product, potential claimants should be aware that pursuing civil litigation involves working within applicable statutes of limitations, which vary by state and by disease type. Mesothelioma and other asbestos-related diseases carry specific discovery rules in most jurisdictions that toll the statute of limitations from the date of diagnosis rather than the date of exposure.

Individuals who worked in industrial settings during the years when Number One Plus Cement was in production—or who were secondarily exposed through family members who brought asbestos fibers home on their clothing—may have legal options available. Consulting with an attorney who specializes in asbestos litigation is strongly recommended to evaluate the specific facts of any potential claim, identify all responsible parties, and determine the appropriate legal venue.

This article is provided for informational purposes and documents historically verified facts regarding asbestos-containing products. It does not constitute legal advice. Individuals with potential asbestos exposure claims should consult a qualified attorney.