Paco Joint Compound

Product Description

Paco Joint Compound was a gypsum-based finishing product manufactured and distributed during the 1970s, with documented production spanning from approximately 1970 through 1978. The compound was formulated for use in drywall finishing applications, serving as a material for filling seams, covering fasteners, and creating smooth wall and ceiling surfaces in both residential and commercial construction settings.

The product was brought to market under the Paco brand through Than-Distributing, a company involved in the supply chain of construction finishing materials during this period. Joint compounds of this era were widely used across the building trades, and Paco Joint Compound was among the products available to contractors and workers engaged in interior finishing work during the years of its production.

During the 1970s, joint compounds represented a standard component of drywall construction. Workers in industrial and commercial environments encountered these products routinely as part of interior build-out and renovation projects. The relatively short production window for Paco Joint Compound — approximately eight years — coincides directly with a period in which the construction materials industry was transitioning away from asbestos-containing formulations following increasing regulatory and scientific scrutiny of asbestos as a health hazard.

Asbestos Content

Paco Joint Compound contained chrysotile asbestos as a functional ingredient in its formulation. Chrysotile, also known as white asbestos, is a serpentine-class mineral fiber that was widely used in building material manufacturing throughout the mid-twentieth century. In joint compound applications, chrysotile fibers were incorporated to enhance workability, improve bonding strength, and add durability to the dried compound surface.

Chrysotile asbestos was the predominant fiber type used in joint compounds during the era when Paco was produced. Although chrysotile has sometimes been characterized as less hazardous than amphibole asbestos varieties such as crocidolite or amosite, scientific and regulatory consensus — including positions established by the Environmental Protection Agency under AHERA (the Asbestos Hazard Emergency Response Act) and OSHA standards — affirms that chrysotile is a known human carcinogen capable of causing mesothelioma, asbestosis, and lung cancer. No safe threshold for chrysotile exposure has been established by federal health authorities.

The use of chrysotile in joint compound formulations became a subject of significant public health concern beginning in the 1970s. Regulatory pressure and liability exposure led many manufacturers to reformulate their products, and the 1978 endpoint of Paco Joint Compound’s documented production period aligns with broader industry changes occurring in response to these developments.

How Workers Were Exposed

Workers who handled, mixed, applied, sanded, or disturbed Paco Joint Compound during its production years faced the primary routes of occupational asbestos exposure associated with this product category. Industrial workers generally — including those engaged in construction finishing, building maintenance, and renovation work — represented the population most likely to encounter this product during the course of their duties.

The highest exposure events associated with joint compound products typically occurred during dry sanding. After joint compound was applied and allowed to cure, workers would sand the hardened material to achieve a smooth, level surface. This process generated significant quantities of fine airborne dust. When an asbestos-containing joint compound was sanded, chrysotile fibers became suspended in the air, creating inhalation hazards for the worker performing the sanding as well as for others present in the same work area.

Mixing dry joint compound formulations also presented exposure risks. Workers who opened bags of powdered compound and mixed the contents with water could disturb settled fiber concentrations, releasing asbestos into the breathing zone before any wet application occurred.

Additionally, workers involved in demolition, renovation, or removal of previously installed drywall assemblies — including workers who scraped or mechanically disturbed cured joint compound — faced secondary exposure risks. Asbestos fibers encapsulated within dried joint compound can be re-released when the material is physically disturbed, meaning that exposure risks extended beyond the original installation period and affected later generations of workers performing maintenance or remodeling activities in structures where asbestos-containing compounds had been applied.

The industrial work environments in which this product was used frequently lacked adequate ventilation controls or respiratory protection, conditions that would be addressed by later OSHA asbestos standards but that were not uniformly enforced or observed during the period when Paco Joint Compound was in use.