Joint Compound and Mesothelioma
What is Joint Compound?
Joint compound, also known as "mud," is used by builders to finish the seams between pieces of drywall. After drywall is nailed up, paper "drywall" or "joint" tape is used to cover the gaps between adjoining pieces of drywall. Joint compound is spread over the tape to create a smooth, continuous wall surface. Joint compound may need to be applied in several coats, with each coat being allowed to dry and then sanded smooth before the next layer is added. Joint compound can also be used to patch cracks, fill small holes in plaster or drywall, and smooth over rough spots.
Historically, some brands of joint compound have contained asbestos. Asbestos filler was used partly for its flame-, moisture- and insect- resistant properties. Asbestos was also used in these products for its thixotropic properties. That is, it helps give the joint compound a smooth, easily spreadable consistency, without changing the product's basic nature.
Joint compound could be purchased as a dry powder, to be mixed with water by the user, or as a pre-mixed paste. Dry-mix joint compound usually came in sturdy paper bags, similar to the bags used for flour and sugar. Ready-mixed joint compound came in cans or rigid plastic buckets.
Who Works with Joint Compound?
In the construction trades, the "taper" or "drywall taper" is responsible for taping and mudding interior drywall in preparation for finish materials (paint, wallpaper, etc.). On large projects, an apprentice might have the task of mixing powdered asbestos joint compound into a paste for the taper to use. Homeowners doing their own remodeling and renovation work might also perform these tasks.
Where is Joint Compound Found?
Joint compound is found wherever drywall is used; primarily for interior walls of houses and other buildings. Asbestos-containing joint compound is most prevalent in buildings built after World War II up until the late 1970's.
Joint compound was sold in a variety of retail outlets, including hardware stores and lumber yards.
How Does Joint Compound-related Asbestos Exposure Occur?
Tapers and other tradespeople mixing joint compound paste from powdered product and water may be exposed to airborne asbestos fibers. Joint compound is normally applied in thin coats, allowed to dry and then sanded smooth before the next coat is applied, creating additional exposure. Other construction workers and bystanders in the immediate area may also be exposed to airborne asbestos. Demolition and remodeling work may disturb dried joint compound, releasing fibers into the air.
Factory workers who handled bags of raw asbestos fiber when mixing and packaging joint compound products for retail sales were also at risk of exposure to the airborne fibers. Dry-mix joint compound was usually packaged in heavy paper bags, which could leak or break open in transport or storage, creating exposure for truck drivers and hardware store and lumber yard employees and customers.
Demolition workers, workers who manufacture and package joint compound, freight haulers transporting shipments of joint compound, and sales people in hardware stores may also be at risk of asbestos exposure from handling joint compound, mainly in its dry form. Other trades people working in a room where mudding or demolition is being done may also be exposed to airborne asbestos fibers.
Common Diseases Associated with Asbestos Exposure
Until the mid-1970's, the strong link between asbestos exposure and pulmonary disease (i.e. malignant mesothelioma) was not common knowledge. Workers who have handled asbestos-containing joint compound and other workers or supervisory personnel working in the general vicinity, may have inhaled airborne asbestos fibers while on the job without even being aware of the fact that asbestos causes mesothelioma. This put them at significant risk for developing one of the following asbestos-associated diseases: pleural mesothelioma, peritoneal mesothelioma, pericardial mesothelioma, asbestos cancer and asbestosis. In addition, workers often brought asbestos fibers home on their clothes, putting their family members, especially women, at risk for developing one of the above diseases. Those diagnosed with the disease generally do not have a favorable mesothelioma prognosis. A disease like mesothelioma can also take 30-40 years to develop (i.e. has a long latency period) following initial exposure.