Asbestos Cement Siding Shingles — National Gypsum Co.
Asbestos cement siding shingles were a widely used exterior building material throughout much of the twentieth century. National Gypsum Co., a major manufacturer of construction and building products, produced asbestos-containing materials across multiple product categories, and litigation records document the company’s involvement in the manufacture and distribution of products containing asbestos fibers. Workers involved in the installation, removal, and disturbance of asbestos cement siding shingles faced potential exposure to airborne asbestos fibers, a recognized cause of serious and life-threatening respiratory diseases.
Product Description
Asbestos cement siding shingles were flat or textured exterior cladding panels designed to mimic traditional wood shingles or slate roofing. Manufactured using a slurry process that combined Portland cement, water, and asbestos fibers, these shingles were prized in the construction industry for their durability, fire resistance, moisture resistance, and relatively low cost. They were marketed heavily to residential, commercial, and industrial building owners as a low-maintenance alternative to wood siding.
National Gypsum Co. operated across a broad range of building material segments, including ceiling tile, cement pipe, joint compound, pipe insulation, and refractory products. Litigation records document that asbestos-containing products manufactured and distributed under the National Gypsum name were used extensively in residential and commercial construction projects across the United States during the mid-to-late twentieth century.
Asbestos cement siding shingles were installed on homes, apartment buildings, schools, industrial facilities, and commercial structures. Many of these buildings still stand today, meaning the material remains present in the built environment and continues to pose a potential hazard when disturbed during renovation, demolition, or repair work.
Asbestos Content
Asbestos cement siding shingles in this product category were manufactured using asbestos fibers — most commonly chrysotile (white asbestos), though other fiber types were also used in certain formulations — blended with Portland cement to create a rigid, weather-resistant panel. The asbestos fibers provided tensile reinforcement within the cement matrix, preventing cracking under thermal expansion, impact, and weathering stress.
Plaintiffs alleged that National Gypsum Co. incorporated asbestos fibers into its building material products despite internal and industry-wide awareness of the health hazards associated with asbestos exposure. Litigation records document allegations that adequate warnings were not provided to workers or end users about the risks posed by cutting, drilling, sanding, or otherwise disturbing these asbestos-containing shingles.
When intact and undisturbed, asbestos cement shingles are generally considered a lower-risk material because the fibers are bound within the hardened cement matrix. However, the U.S. Environmental Protection Agency’s Asbestos Hazard Emergency Response Act (AHERA) regulations and OSHA standards recognize that any mechanical disturbance — including sawing, grinding, breaking, or power-washing — can release respirable asbestos fibers into the air. OSHA’s asbestos standards for construction (29 CFR 1926.1101) classify asbestos cement products as Class III or Class IV asbestos-containing material depending on the nature of the work being performed.
How Workers Were Exposed
Industrial workers generally, as well as tradespeople involved in construction, renovation, and demolition, faced exposure to asbestos fibers when working with or around asbestos cement siding shingles. Litigation records document that the primary exposure pathways involved the mechanical disturbance of these materials during installation and, later, during removal and abatement activities.
Installation-phase exposures occurred when workers cut shingles to fit using hand saws, circular saws, or snips. Sawing and scoring asbestos cement panels generated visible dust that plaintiffs alleged contained respirable asbestos fibers. Workers in close proximity to cutting operations — including carpenters, siding installers, and laborers — inhaled this dust in the absence of adequate respiratory protection or engineering controls.
Renovation and demolition exposures are particularly significant because asbestos cement siding shingles installed decades ago are now being disturbed during remodeling projects, re-siding operations, and building demolition. Litigation records document that workers tasked with removing old asbestos cement siding faced substantial fiber release, especially when shingles were broken, pried off with tools, or allowed to fall and shatter. Power washing and abrasive cleaning of weathered shingles was also identified as a potential high-exposure activity.
Bystander and secondary exposures have also been documented in litigation records, with plaintiffs alleging that workers in adjacent trades — painters, electricians, plumbers, and general laborers — were present at job sites where asbestos cement shingles were being cut or removed, exposing them to airborne fibers without their knowledge or consent.
Occupational exposure to asbestos fibers is causally associated with mesothelioma, asbestosis, lung cancer, pleural plaques, and other serious pulmonary diseases. These conditions frequently have latency periods of twenty to fifty years between initial exposure and clinical diagnosis, meaning workers exposed during the peak production and installation era of asbestos cement shingles may only now be receiving diagnoses.
Documented Trust Fund / Legal Options
National Gypsum Co. filed for bankruptcy protection, and as part of those proceedings, the National Gypsum Settlement Trust was established to compensate individuals harmed by exposure to asbestos-containing products attributed to National Gypsum Co. Claimants seeking compensation through the trust must demonstrate a qualifying diagnosis and establish exposure to a National Gypsum asbestos-containing product.
Because this product falls under Tier 2 — Litigated status, individuals pursuing claims related to asbestos cement siding shingles manufactured by National Gypsum should be aware that litigation records document the evidentiary standards typically required to connect a specific product to a compensable asbestos-related disease. Plaintiffs alleged exposure to National Gypsum asbestos-containing products across multiple product categories, including ceiling tile, cement pipe, joint compound, pipe insulation, and refractory materials, as well as siding and exterior cladding products.
Eligible claim categories typically include:
- Mesothelioma claims — generally considered the highest-priority disease category in asbestos litigation and trust fund administration
- Lung cancer claims — typically requiring documented occupational asbestos exposure combined with a confirmed lung cancer diagnosis
- Asbestosis and non-malignant disease claims — including pleural plaques, pleural thickening, and other non-malignant asbestos-related conditions meeting trust eligibility thresholds
- Wrongful death claims — filed on behalf of deceased individuals whose death was attributed to an asbestos-related disease
Individuals who worked in construction, renovation, demolition, or industrial settings and who were exposed to asbestos cement siding shingles or other National Gypsum asbestos-containing products should consult with an attorney experienced in asbestos litigation to evaluate their legal options. Statutes of limitations vary by state and typically begin running from the date of diagnosis rather than the date of exposure. Early consultation is advisable to preserve claim eligibility and gather necessary exposure documentation, including employment records, union records, and product identification evidence.