Plaster
Asbestos in Plaster and Other Building Materials
Plaster is a mortar-like substance that is used for a wide variety of purposes including building construction and finishing, medical care, and even modeling and the arts (including theatrical and film sets). Plaster comes in three main varieties: gypsum (also known as Plaster-of-Paris), lime (employed by visual artists) and cement.
The use of plaster to add fire-resistance to walls and other surfaces was widespread. Plaster acts as a flame retardant by releasing water vapor when exposed to flame. It is also an excellent heat insulator, preventing the transfer of heat to inner surfaces.
In the past, asbestos fibers were frequently added to plaster mix. These fibers were added to improve the flame retardant properties of the material, as asbestos is extremely heat-resistant. Most often, the asbestos used was a type known as white chrysotile.
Tremolite is a form of amphibole asbestos. These fibers are long and stiff, acting like microscopic spears once embedded inside the lung tissue. Tremolite was never commercially mined, but is a frequent contaminant of other commercial substances including vermiculite, a common ingredient found in some types of fibrous cement plaster.
Plaster Products Containing Asbestos
The following partial list of plaster products were known to contain asbestos:
| Product Name | Start Year | End Year |
|---|---|---|
| Georgia-Pacific Acoustical Plaster | 1950 | 1974 |
| Georgia-Pacific Lite Acoustical Plaster | 1958 | 1964 |
| Georgia-Pacific Patching Plaster | 1956 | 1976 |
| Keene Uni-Coustic | 1963 | 1971 |
| National Gypsum Gold Bond Acoustical Plaster | ||
| National Gypsum Gold Bond Fire-Shield Plaster | 1958 | 1970 |
| National Gypsum Gold Bond Macoustic | 1942 | 1947 |
| National Gypsum Gold Bond Patching Plaster | ||
| National Gypsum Gold Bond Perfo-Lyte Acoustical Plaster | 1955 | 1972 |
| National Gypsum Gold Bond Plasters | ||
| National Gypsum Gold Bond Spackling Plaster | ||
| National Gypsum Gold Bond Wood Fibered Plaster | ||
| Synkoloid Plastibond | 1950 | 1976 |
| Synkoloid Synko Patch Rite Patching Plaster | ||
| Synkoloid Synko Plaster of Paris | ||
| United States Gypsum Cement Plaster Regular | 1943 | 1947 |
| United States Gypsum Firecode Plaster | ||
| United States Gypsum Gypsum Woodfibre Plaster | ||
| United States Gypsum Imperial Gypsum Cement Plaster | ||
| United States Gypsum Imperial Plaster | ||
| United States Gypsum Red Top Cement Plaster | 1920 | 1958 |
| United States Gypsum Red Top Firecode Plaster | 1962 | 1969 |
| United States Gypsum Red Top Gypsum Plaster | 1920 | 1958 |
| United States Gypsum Red Top Patching Plaster | ||
| United States Gypsum Red Top Plaster | ||
| United States Gypsum Structolite | 1950 | 1975 |
| United States Gypsum Structo-lite Perlited Gypsum Plaster | ||
| United States Mineral Cafco Sound-Shield | ||
| W.R. Grace Hi-Sorb Plaster | ||
| W.R. Grace Zono-Coustic | 1960 | 1973 |
| W.R. Grace Zonolite Acoustical Plaster | 1945 | 1972 |
Hazards Associated with Plaster Products
Although the deliberate use of asbestos in plaster mix has been banned in most of the industrialized world, the use of asbestos-containing vermiculite continued for many years. Unfortunately, this type of plaster remains in many older structures, and continues to pose a health threat to building renovators and demolition workers. When intact, the plaster poses relatively little risk of asbestos exposure because the asbestos fibers are held in place by the surrounding material. When the plaster becomes worn, abraded, or scratched, however, the individual fibers can enter the atmosphere and be inhaled. Inhaled asbestos is the primary cause of asbestosis and malignant mesothelioma.
Sources
Bowker, Michael. Fatal Deception: The Untold Story of Asbestos (New York: Touchstone, 2003)
