Bird Asbestos-Reinforced Roofing Felt

Product Description

Bird asbestos-reinforced roofing felt was a construction material manufactured by Bird & Son, Inc., a Massachusetts-based company with roots stretching back to the nineteenth century. The company became one of the United States’ prominent producers of roofing and building materials, and its product line included asbestos-containing roofing felts that were widely distributed across commercial, industrial, and residential construction markets.

Roofing felt serves as an underlayment material installed beneath finished roof coverings such as shingles, tiles, or metal panels. It functions as a secondary moisture barrier, provides an additional layer of thermal resistance, and helps protect the structural roof deck during and after installation. Asbestos was incorporated into roofing felt formulations by Bird & Son and other manufacturers because the mineral offered practical material advantages: it resisted fire, added tensile strength, improved dimensional stability, and enhanced the product’s durability under exposure to heat and moisture cycles.

Bird & Son’s asbestos-reinforced roofing felt was a standard industrial product during much of the twentieth century. It was sold through building supply distributors, used in new construction projects, and applied during roofing repair and replacement work at facilities across the country. Its widespread availability meant that a broad range of workers encountered this material over the course of their careers.

Asbestos Content

Asbestos-reinforced roofing felts produced during this era typically incorporated asbestos fibers — most commonly chrysotile, though other fiber types appeared in some formulations — blended with organic binders and bituminous materials to form a cohesive sheet product. The asbestos fibers were integrated throughout the felt matrix, providing structural reinforcement and improving fire resistance.

Asbestos content in roofing felt products of this type was not incidental. The fiber was a deliberate functional component, and products could contain meaningful percentages of asbestos by weight depending on the specific grade and intended application. Regulatory frameworks that emerged later in the twentieth century, including standards developed under the Asbestos Hazard Emergency Response Act (AHERA) and guidelines issued by the Occupational Safety and Health Administration (OSHA), established that fibrous asbestos-containing materials of this nature posed health risks when fibers were released into breathable air.

OSHA standards classify airborne asbestos as a serious occupational hazard, with no safe level of exposure established for carcinogenic fiber types. Diseases associated with asbestos exposure — including mesothelioma, asbestosis, and asbestos-related lung cancer — can develop decades after the initial exposure events, which is why workers who handled products like Bird asbestos-reinforced roofing felt during earlier decades of their careers may only now be experiencing health consequences.

How Workers Were Exposed

Industrial workers and roofing trades personnel represent the primary exposure population for Bird asbestos-reinforced roofing felt. Occupational exposure occurred at multiple points across the product’s lifecycle, from manufacturing through installation and eventual removal or repair.

During installation, workers unrolled, cut, trimmed, and fastened roofing felt to roof decks as part of standard roofing operations. Cutting the felt with utility knives or snips generated asbestos-containing dust at the cut edge. Tearing or trimming irregular sections produced similar dust releases. Workers operating in close proximity to these activities — including laborers assisting roofers, sheet metal workers, and general construction workers — could inhale fibers without being the individual directly handling the material.

During removal and replacement, existing asbestos-reinforced roofing felt that had become brittle, deteriorated, or damaged was frequently stripped from roof decks during re-roofing projects. Aged felt in poor condition tended to break apart more readily, generating higher concentrations of airborne dust than intact material. Workers removing old roofing without respiratory protection or engineering controls were exposed to fiber releases during these operations.

In industrial settings, maintenance workers and facilities personnel performed roofing repairs on a routine basis, often without formal awareness that the felt they were handling contained asbestos. Industrial maintenance schedules required periodic inspection and repair of roof systems, and workers who performed these tasks repeatedly over years or decades accumulated cumulative exposures.

Bystander exposure also occurred on job sites where roofing work was underway. Other tradespeople working in adjacent areas — electricians, pipefitters, HVAC technicians, and general laborers — could inhale fibers released by roofing operations without directly handling the felt themselves.

Because roofing work often took place in outdoor or semi-enclosed environments, and because the episodic nature of roofing tasks meant exposures were intermittent, the hazard was not always apparent to workers or their employers at the time. OSHA’s current permissible exposure limit for asbestos reflects the understanding that even short-duration, high-intensity exposures carry meaningful health risk.