From around 1900 until well into the 1980s, asbestos was a common ingredient in nearly every type of building material. One of the most dangerous asbestos-containing building materials was the different types of plasters.
Wood Fiber Plaster and Asbestos
Many older homes are filled with all types of asbestos-containing products. In addition to decorative plaster, another common building material made with asbestos was wood fiber plaster (used to fill cracks and holes before staining wood surfaces). Until the 1980s, asbestos was added to some wood fiber plaster to increase its strength and ability to resist fire. Wood fiber plaster is used to fill cracks and holes prior to staining. It has been, and continues to be widely used by carpenters and others in the construction industry. One such product used by many woodworkers prior to 1978 was RED TOP Wood Fiber Plaster, marketed by the United States Gypsum Company.
Up until the 1980s, the various types of wood fiber plaster that were available for woodworking and finishing projects contained calcified gypsum (a substance similar to chalk), cellulose fibers from actual wood and asbestos. The asbestos – primarily “brown” asbestos, or amosite – was added to increase the tensile strength of the plaster as well as making it flame retardant.
Once applied and allowed to harden and dry, such wood fiber plaster could be sawn, drilled, nailed and sanded just like real wood. The difference is that these activities released millions of microscopic, needle-like fibers that once taken into the lungs would burrow through the lung tissues from the inside emerging into the pleural layers on the surface of the lungs and inner chest wall. During this process, these hard fibers interact with cellular DNA in ways that medical science has yet to determine, causing them to become cancerous and resulting in mesothelioma.
The wood fiber plaster that is manufactured, marketed and used today does not contain asbestos: the most common strengthening agent is synthetic resin. However, asbestos-containing wood fiber plaster may be present in older homes built prior to the mid 1980s. If the walls of the building are in good condition and have a solid coat of paint, it is likely that such plaster embedded in the walls has thoroughly dried and is therefore not friable – meaning that the best course of action is to leave it be.
Patching Plaster and Asbestos
Patching plaster has been widely used for its ability to plug gaps and holes that are found in ceilings and walls. One component of patching plaster that made it so effective was asbestos. As a lightweight, fire-resistant, durable and inexpensive material, asbestos was favored by a number of industries. Despite its mass appeal, asbestos was also found to be highly toxic. As a result, it led to the development of asbestosis and a deadly form of cancer known as mesothelioma.
Is Patching Plaster Asbestos Still Legal?
While many industries have known about patching plaster asbestos and the harmful effects of its exposure since the 1930s, asbestos-laden products remained in production for decades to follow. It wasn’t until the 1980s that consumer products ceased to be manufactured without asbestos. This was primarily due to a ban the Consumer Product Safety Commission instituted in 1977. This ban outlawed the use of asbestos in patching plaster and other materials.
Unfortunately, much harm was already done and many people ended up suffering from lung cancer, asbestosis, mesothelioma and other conditions related to asbestos exposure. Besides, this ban only applied to new products manufactured, so previously produced materials that contained asbestos still remained. For this reason, anyone who works or lives around material that contains patching plaster manufactured prior to the 1980s should be checked for mesothelioma.
Decorative Plaster and Asbestos
The Environmental Protection Agency maintains that asbestos is not a danger to homeowners, provided it is contained properly. It is only when asbestos-containing materials are disrupted and have the potential to become airborne that there is cause for alarm. If the microscopic asbestos fibers are inhaled, they can lodge in the lungs and may cause mesothelioma or other asbestos-related diseases.
A simple solution to ensure that the asbestos in decorative plaster walls, ceilings, or other decorative finishes remains contained is to paint over it. The paint acts as a glue that binds the fibers and prevents them from becoming airborne.
If the decorative plaster in your home is crumbling or damaged in any way, or if you are about to embark on a renovation project that is likely to disrupt it, you’ll want to enlist the help of a trained asbestos management professional who can determine if your plaster does, in fact, contain asbestos, and who can safely contain or remove it if it does.
While manufacturers ceased using asbestos as an additive to decorative plaster in the 1970s, there are older homes in the United States that still contain this toxic material. Sadly, those in the building construction, renovation, or demolition business who worked with decorative plaster over the years are more at risk for developing an asbestos-related disease such as mesothelioma.