Plasterers are laborers dealing with plaster, drywall and other substances utilized in the construction and finishing of interior and exterior walls. Asbestos was used in plaster compounds prior to the 1980s, but it can still be found in building materials used in houses as late as the early 1990s.
Asbestos Use in Plaster
Asbestos was used in plaster as a fireproofing agent. Because of the mineral's native ability to resist flame and heat, it seemed an ideal inclusion in the substance that would coat interior walls. This compound would then resist flame and retard the spread of potential house fires.
Chrysotile asbestos was combined with bentonite, a type of clay that swells and turns into a gel when exposed to water, to create the most common kind of plaster found in building construction.
Asbestos in Paneling
Asbestos was also used in paneling that would have been coated by plaster. The paneling itself was a thin cement sheet infused with fibrous asbestos and then used in interior and exterior applications. The panels were manufactured prior to the 1970s but can be found in construction up to the early 1980s.
Asbestos in Insulation
Monokote and Zonolite were types of insulation marketed by the W.R. Grace Company of Maryland and frequently encountered by plasterers in construction.
Monokote was a type of sprayed-on insulation that was banned by the Environmental Protection Agency in 1973, but Congress raised the acceptable level of asbestos in insulation to 1 percent. This is known as the "Grace Rule" after W.R. Grace.
Zonolite is a type of insulation manufactured until the 1990s. The primary ingredient in this product consisted of vermiculite. Vermiculite itself is harmless, but the vermiculite was mined near asbestos deposits and so it often contained unsafe levels of the mineral.
Dangers on the Job
It is generally understood that some jobs are riskier than other ones. Still, in America today, people have come to expect that on-the-job hazards will be minimized, risks will be clearly understood, and companies will strive to maintain safe workplaces. Until relatively recently, however, in terms of exposure to asbestos, employees frequently labored without respirators or other protective gear in spaces where asbestos particles clouded the air.
Asbestos and Its Health Effects
What we call asbestos is actually a group of minerals that is broken into two categories. Chrysotile, or "white" asbestos, is the only member of the serpentine group and was the form most frequently used. Not normally associated with mesothelioma or asbestos cancer, this type is a relatively soft variety of the mineral. Abrasions on the interior surfaces of the lungs do happen when serpentine particles are breathed in, however. This then causes an accumulation of scar tissue that can then be a leading cause of asbestosis.
Amphibole asbestos is the second category and is much more dangerous. A unusual, but often lethal, disease caused by asbestos called mesothelioma is caused by inhaling asbestos, especially the amphibole forms. The pleural variety of the illness, one which attacks the tissue that lies between the lungs and the pleural cavity, is the most common. Extensive contact with amphibole asbestos is also a cause of pericardial or peritoneal mesotheliomas, diseases that affect tissue surrounding the heart and digestive tract, respectively.
The Advantages of Asbestos
Ironically, asbestos was used in building construction and in many products because of its ability to save lives. Serpentine asbestos is one of the best insulators known when it comes to fire and temperature extremes and has been used for this purpose for centuries. In addition, amphibole asbestos had other useful characteristics. For instance, "brown" asbestos, or amosite, is high in iron content, making it impervious to caustic chemicals. "Blue" asbestos, or crocidolite, is a particularly good insulator against electric current and was frequently used whenever high voltage was a concern. Depending on the application, various types of fibers were combined to create asbestos-containing materials (ACMs) that could protect lives and property against flames, extreme temperatures, electrical contact and caustic chemicals.
As long as it was solid, asbestos posed no immediate hazard. However, as ACMs aged, they became friable, or able to be reduced to powder by hand pressure alone. When friable, asbestos fibers are readily dispersed into the environment; once they enter the body through inhalation or ingestion, they can cause numerous health problems. Asbestos dust that coated employees' skin, hair, or clothing could also place others at risk unless effective safety measures, including the use of on-site uniforms and showers, were followed.
A Ticking Bomb
In contrast to most workplace injuries, which are easily observed and known about immediately following the causing incident, asbestos-related diseases may take many, many years to manifest. With such a long time between asbestos exposure and the onset of symptoms, a worker might not even connect his or her current condition with work done 10 or more years ago. Mesothelioma radiation and other experimental methods are being developed, and early detection gives patients the best chance to beat the previously always-fatal disease. These advancements can help better the usually grim mesothelioma survival rate. People who have worked as plasterers, as well as anyone who lived with them, should therefore notify their physicians about the chance of exposure to asbestos.Sources
Bowker, Michael. Fatal Deception: The Untold Story of Asbestos (New York: Touchstone, 2003)
The Age - Dow Chemical Liable in Asbestos-Related Case
US Inspect - Cement Asbestos Siding
University of Wisconsin - Asbestos Containing Material (ACM) - Laboratories and Shops
University of Wisconsin - Asbestos Disposal