Spackle started out as a brand name for a powder that was designed to be mixed with water to form a kind of plaster that is still used for patching holes and cracks in walls, ceilings and wood prior to the application of paint. Today, several companies market an almost identical product, which is still identified by the generic term “spackle.” In Australia , Canada and the U.K. , “spackle” is known as polyfilla. Like spackle, this too is a generic term that originated as a brand name.
Like many construction materials manufactured throughout the 20th century, spackle contained substantial amounts of asbestos – in some cases, up to twenty percent. What made this spackle exceptionally harmful – causing asbestos disease to be a leading occupational hazard for drywall and plaster workers – is the fact that it is marketed in the form of a dry powder. This made the asbestos highly friable – which is to say that the individual fibers easily became airborne, where they were liable to be ingested into the lungs by construction workers.
Today, there are several brands of spackle for which the claim “asbestos-free” is made. Under current laws, this is true. In 1973, W.R. Grace & Company urged the U.S. Congress to make an exception to asbestos legislation under consideration. Known as the “Grace Rule,” it is still in force. The “Grace Rule” allows corporations to market products that contain up to one percent asbestos as being “asbestos-free.”
Despite this “1% Rule,” a report that was published in the May 1979 edition of the American Industrial Hygiene Association Journal – one of the authors of whom was renowned asbestos disease specialist Dr. Irving Selikoff – stated that air samples taken at construction sites where spackle was being used showed “fiber concentrations exceeding, by several times, the maximum level permitted by United States Government regulations.”
Spackle in older homes and buildings poses special risks, particularly when it comes to renovation work and demolition. Nailing, sawing, drilling or breaking up old drywall or “popcorn” ceilings can cause old spackle to become friable. Unfortunately, there is no reliable way of determining whether or not any material contains asbestos by visual means alone. The safest procedure is to have testing performed by professional asbestos contractors prior to starting work. If the building in question is not your primary private residence, most state laws require that you hire a professional.