Asbestos was one of the ingredients plasterers worked with prior to the 1980s. In addition, it continues to be present in buildings constructed as late as the early 1990s. Plasters are among those in construction trades who have been exposed to asbestos fibers on the job.
It is out of fear of fire that asbestos became king for many decades; this marvelous substance – a kind of stone that could be woven into cloth – was not only fire and heat resistant, but could also protect one from electrical current and caustic chemicals.
Decades later, it has become all-too-apparent that the cure was as bad – if not worse – than the disease. Those who suffer from an asbestos-related disease such as asbestosis or pleural mesothelioma (The most common form of asbestos cancer) essentially die from slow asphyxiation – and the process can take years.
According to the McGraw-Hill Dictionary of Scientific and Technical Terms, “asbestos plaster” is defined as “a fireproof insulating material generally composed of asbestos with bentonite as the binder”. Bentonite is a type of clay that swells and turns into a gel when exposed to water, found in the U.S. primarily in Wyoming, Arizona and Mississppi.
The types of asbestos added to such plaster since the 1920s was primarily chrysotile. This is a softer type of asbestos with curled, spring-like fibers that some have claimed is less deadly than other types. This claim was disproven in 1996 by medical researchers at New York’s Mount Sinai Hospital, who also discovered that chrysotile was likely to be contaminated with tremolite, a much stronger form of asbestos with fibers that were potentially much more harmful and often led to the development of mesothelioma.
Asbestos cement paneling was frequently used in homes constructed prior to 1980. These were literally thin sheets of cement that contained various types of asbestos in order to hold them together, as cement is not particularly strong when only a ½” thick. This type of paneling has not been made since the early 1970s.
Other construction materials plasterers were likely to encounter were actually marketed under brand names by the W.R. Grace Company of Maryland. These were called Monokote and Zonolite.
W.R. Grace Inc. Asbestos Products
Monokote™ was a type of sprayed-on insulation. This substance was banned by the Environmental Protection Agency (EPA) in 1973; however, corporate lobbyists working for the W.R. Grace Corporation were able to pressure Congress into passing a law that established an “acceptable level” of asbestos content at 1%. The “Grace Rule” has never been changed.
Zonolite™ is a type of insulation manufactured up until the early 1990s. The primary ingredient in this product consisted of a substance known as vermiculite, a relatively innocuous form of clay. However, the sources for vermiculite were usually in the vicinity of asbestos mining operations, particularly in and around the town of Libby, Montana, where W.R. Grace owned and operated several mines. As a result, a great deal of vermiculite was contaminated with asbestos fibers.