Asbestos Cement Siding Shingles / G.B. Corrugated 400 / Classic Shake Siding / Woodgrain Siding / Asbestone Roofing — National Gypsum Co.

National Gypsum Company produced a family of asbestos-reinforced building products under several trade names from approximately 1953 through 1981. Sold under designations including G.B. Corrugated 400, Classic Shake Siding, Woodgrain Siding, and Asbestone Roofing, these products were manufactured as asbestos cement composites intended for residential and commercial construction markets. Workers involved in the manufacture, installation, and handling of these materials may have faced significant asbestos exposure during the decades these products remained in active production and widespread use.

Product Description

National Gypsum Company, headquartered in Buffalo, New York, was one of the major building materials manufacturers in the United States during the mid-twentieth century. The company’s roofing and siding product lines incorporated asbestos cement technology that was broadly accepted by the construction industry during this period as a durable, fire-resistant, and weather-resistant solution for exterior building applications.

The G.B. Corrugated 400 was a corrugated sheet product designed for industrial and agricultural roofing and siding applications, marketed for its structural rigidity and resistance to moisture and fire. Classic Shake Siding and Woodgrain Siding were designed to mimic the visual appearance of natural wood shakes and grain textures while offering the practical advantages attributed to asbestos cement composites — namely dimensional stability, resistance to rot, and reduced combustibility. Asbestone Roofing represented the company’s asbestos-reinforced flat and corrugated roofing sheet offerings.

These products were manufactured and distributed from approximately 1953 through 1981, coinciding with a period of intense residential and commercial construction activity in the United States. They were available through building supply distributors and contractors across the country, making them fixtures on job sites throughout multiple decades.

Asbestos Content

All products in this group were manufactured using chrysotile asbestos, the most commercially prevalent form of asbestos used in building materials during the twentieth century. In asbestos cement products, chrysotile fibers were blended with Portland cement and water, then formed under pressure into sheets, shingles, or corrugated panels. The asbestos fiber content in asbestos cement building products of this type typically constituted a substantial portion of the finished product by weight, with chrysotile serving as the primary tensile reinforcement within the cement matrix.

Chrysotile asbestos, while sometimes characterized as less hazardous than amphibole forms of asbestos, is classified as a known human carcinogen by the International Agency for Research on Cancer (IARC) and is regulated as a hazardous material under the Occupational Safety and Health Administration (OSHA) asbestos standards (29 C.F.R. § 1910.1001 and § 1926.1101) and under the Asbestos Hazard Emergency Response Act (AHERA). The U.S. Environmental Protection Agency (EPA) and OSHA recognize that no safe level of asbestos exposure has been established.

In intact condition, asbestos cement products may release relatively few fibers. However, the material becomes a significant source of airborne asbestos when cut, drilled, sanded, broken, or otherwise disturbed — activities that were routine during manufacture, installation, repair, and demolition.

How Workers Were Exposed

Industrial workers involved in the production of asbestos cement siding shingles and roofing products manufactured by National Gypsum faced potential asbestos exposure at multiple stages of the manufacturing process. Raw chrysotile asbestos arrived at manufacturing facilities in baled or bagged form and required opening, weighing, blending, and feeding into mixing equipment. These dry-handling operations generated airborne asbestos dust that could accumulate in work areas without adequate engineering controls or respiratory protection.

Mixing operations combined chrysotile fibers with cement slurries, and machinery used in forming, pressing, cutting, and curing the finished sheets and shingles presented further opportunities for fiber release. Maintenance and cleanup of manufacturing equipment — including dust collection systems, conveyors, cutting blades, and pressing machinery — exposed maintenance workers and general plant laborers to accumulated asbestos residue.

Litigation records document that plaintiffs alleged exposures occurring across a range of job functions within manufacturing facilities, including line workers responsible for material handling, machine operators overseeing forming and pressing equipment, and maintenance personnel tasked with cleaning and repairing production machinery. Plaintiffs alleged that during periods covered by production from 1953 through 1981, adequate warnings of the health hazards associated with asbestos were not provided to workers, and that engineering controls and personal protective equipment were insufficient or absent in many workplace settings.

Beyond the manufacturing environment, downstream occupational exposures were also the subject of litigation. Plaintiffs alleged that individuals who installed, cut, or removed National Gypsum’s asbestos cement siding and roofing products — including carpenters, roofers, construction laborers, and renovation contractors — were exposed to chrysotile fibers released when products were sawed, nailed, or broken. Demolition and renovation work involving these products, which were installed on structures across the country during the production years, has also been identified in litigation records as a source of ongoing secondary exposure.

The diseases associated with occupational asbestos exposure and documented in litigation involving asbestos cement products include mesothelioma, asbestos-related lung cancer, asbestosis, and pleural disease. These conditions typically have latency periods ranging from ten to fifty years between initial exposure and clinical diagnosis, meaning individuals exposed to National Gypsum products during the 1950s through the 1980s may only now be receiving diagnoses.

National Gypsum Company does not maintain an active asbestos bankruptcy trust fund. The company reorganized under bankruptcy protection in the early 1990s, and while a plan of reorganization was confirmed, the structure of its asbestos liability resolution differed from manufacturers that established dedicated Section 524(g) asbestos trusts of the kind created under the Bankruptcy Code for ongoing claimant compensation.

Individuals diagnosed with mesothelioma, asbestos-related lung cancer, asbestosis, or other asbestos-related diseases who believe their illness stems from exposure to National Gypsum’s asbestos cement siding, roofing, or related products should consult with an attorney experienced in asbestos litigation. Litigation records document that plaintiffs have pursued claims arising from occupational exposures at National Gypsum manufacturing facilities, as well as claims arising from downstream installation and removal of the company’s asbestos cement products.

Because asbestos exposure in occupational settings often involved products from multiple manufacturers, attorneys handling asbestos claims routinely investigate the full range of products a claimant may have encountered. Other manufacturers of asbestos cement building products or related materials present on the same job sites may have established asbestos bankruptcy trusts through which additional compensation may be available. Statutes of limitations governing asbestos personal injury claims vary by state and typically begin to run from the date of diagnosis rather than the date of exposure, but prompt consultation with legal counsel is important to preserve available rights.

Individuals seeking to explore legal options should retain product identification documentation, employment records, medical records confirming an asbestos-related diagnosis, and any available information regarding specific job sites or facilities where exposure to National Gypsum products may have occurred.