Mastics and gunning mix are building materials used to repair or fill industrial materials such as furnaces, tile or flooring. Asbestos was commonly added to these products as it is strong, durable and able to withstand high temperatures.
Mastic is paste-like cement that is used as an adhesive, sealant and joint-filler. Gunning mix is a type of paste applied to metals, plastics, wood or masonry as a repair compound. It may also be used to smooth pitting, rough surfaces or irregularities that may occur in equipment lining. This mix is usually applied using a caulk gun or similar pump gun.
Adhesives like mastic and gunning mix have been used for hundreds of years, but the use of modern construction mastics and gunning mix began in the early 1900s. Many new plastics and rubbers were synthetically produced and several new adhesive products were developed for use in the construction industry.
Many of these mixes were produced for use during World War II. Adding synthetic rubber and other fibers to these mixes allowed them to be more flexible and strong. Asbestos was added to these adhesives to make them resistant to extreme temperatures and chemicals.
After the use of asbestos declined because of health concerns in the 1980s, companies began using alternatives to asbestos in their construction mastic and gunning mix products.
The National Emission Standards for Hazardous Air Pollutants considers construction mastic as a Category I non-friable asbestos-containing material. This classification indicates that mastic contains 1 percent or more asbestos and may emit asbestos fibers if disturbed.
Gunning mix was often made with vermiculite and aluminum. The vermiculite used in gunning mix may be contaminated with asbestos. Before the mix is made into a paste, it comes in powder form and is packaged in bags. When bags are opened, asbestos fibers easily become airborne while gunning mix is measured and mixed.
Construction workers who install, remove, repair or perform other maintenance work may have been exposed to asbestos in mastics and gunning mixes. Workers in the factories that produced these products were also exposed asbestos on a daily basis.
As a result of asbestos exposure from mastics and gunning mixes, a number of lawsuits have been filed against several manufacturers of these products.
In the 1990s, two engineers filed lawsuits against the maker of NARCO Lite Gunning Mix, North American Refractory Company (NARCO). Frederick Moss and Martin Easter were exposed to high levels of asbestos dust when products were mixed. Witnesses testified that a number of NARCO products, including the gunning mix, released a high level of asbestos dust. No workers were wearing respiratory protection.
As a result of the asbestos exposure, both Moss and Easter developed mesothelioma. Moss worked as an engineer from 1946 to 1988 at Alabama Power Company. Easter was an engineer with U.S. Steel from 1941 to 1970. The jury found North American Refractory Company liable and awarded $7 million dollars to Moss, Easter and a third plaintiff who suffered from asbestosis.
The amount of lawsuits forced NARCO into bankruptcy and when it emerged from bankruptcy in 2008, the North American Refractories Company Asbestos Personal Injury Settlement Trust was created to pay future asbestos claims. The trust was funded with $6.32 billion.
Asbestos-containing construction mastic and gunning mix may be applied to a variety of household products such as floor tiles or roofing materials. Some states allow homeowners to abate mastic and gunning mix that is whole and intact, but this is not advised unless the homeowner is fully prepared to take all the legal and safety precautions. Mastic and gunning mix that has been applied to insulation board or lagging should be removed by a certified asbestos abatement contractor.
Keep in mind that many states require homeowners to use professional, trained contractors when removing asbestos products. The EPA also recommends that only licensed, trained professionals abate asbestos materials. Asbestos abatement professionals also prevent homeowners from paying hefty fines if they break federal or state asbestos abatement regulations.
Homeowners can use the following guidelines to ensure professionals are adhering to laws and regulations when removing asbestos-containing mastics and gunning mixes.
Matt Mauney is an award-winning journalist with nearly a decade of professional writing experience. He joined Asbestos.com in 2016, and he spends much of his time reading, analyzing and reporting on mesothelioma research articles to ensure people in the mesothelioma community know the latest medical advancements. Prior to joining Asbestos.com, Matt was a reporter at the Orlando Sentinel. Matt also edits some of the pages on the website. He also holds a certificate in health writing from the Centers for Disease Control and Prevention. Read More