James F. Humphreys & Associates, L.C. has represented thousands of people with asbestos related diseases. The history of asbestos exposure and illness in this country is a tragedy that should not be repeated with other substances, especially materials which have physical or chemical properties similar to asbestos. One new material which industry needs to keep an eye on in terms of potential health effects is carbon nanotubes (CNTs), which are being used in an ever increasing number of applications. Although we do not have good worker studies yet, animal research suggests that CNTs may have health effects similar to asbestos when inhaled.
Everyone is familiar with common forms of carbon like graphite and diamonds. Diamonds have rigid crystalline structures that make them very hard. Graphite, which is used in pencils and as a lubricant, consists of sheets of carbon atoms which can easily slide across each other. A carbon nanotube is like a graphite sheet that has been rolled into a cylinder. In some cases, multiple tubes are stacked within each other, so carbon tubes can be either single walled or multi-walled.
CNTs can be used to form materials that are mechanically strong, flexible, lightweight, heat resistant and electrically conductive. Because of these properties, they have many industrial and biomedical applications, and as time goes on, new uses will undoubtedly be found for these versatile materials. Industrial uses include electronics, batteries, solar cells, super capacitors, thermo capacitors, polymer composites, coatings, adhesives, and inks. Biomedical uses include biosensors, bone grafting, tissue repair, drug delivery, and medical diagnostics.
Worker exposure to CNTs can potentially occur throughout the life cycle of these materials, including processing, use, disposal and recycling. CNTs can become airborne during transfer, weighing, blending and mixing of bulk powders and cutting and drilling of composite materials that contain CNTs.
Animal studies have shown that airborne CNTs can cause adverse lung effects including pulmonary inflammation and rapidly developing, persistent fibrosis (scarring) of the lungs. They can also increase the risk of cancer where animals are exposed to other cancer causing agents. Airborne CNTs can reach the pleural spaces in animal lungs and CNTs injected into the peritoneum of animals can cause mesothelioma, a cancer usually caused by asbestos.
Although we do not have good epidemiology studies in humans yet, the evidence from animal studies is enough that NIOSH, the National Institute of Occupational Safety and Health has recommended various precautions for working with CNTs. Among other things, NIOSH has recommended that facilities that work with CNTs conduct medical surveillance and screening programs for workers, train and educate workers about CNTs, provide personal protective equipment such as respirators, clothing & gloves, and limit airborne exposures to CNTs so they do not exceed 1 microgram per cubic meter of carbon over a 8 hour time weighted average (TWA).
Asbestos was an occupational tragedy because employers exposed millions of workers to a deadly substance that they knew or should have known would be harmful to their employees. We should learn from this experience so that there will never be “another asbestos.”
If you or a loved one has been seriously injured by exposure to asbestos or some other toxic substance, please contact us for a free initial consultation at 304-881-0652 (local) or 877-341-2595 (toll free). You may also contact us through our website, http://www.jfhumphreys.com.
Current Intelligence Bulletin 65: Occupational Exposure to Carbon Nanotubes and Nanofibers,” Publication #2013-145, April, 2013, available on line at https://www.cdc.gov/niosh/docs/2013-145/pdfs/2013-145.pdf