By Rebecca Cohen
Wooden furniture surrounds us everywhere in our homes, in our classrooms, and in our workspaces. We sit at our wooden desks, eat on our wooden tables, keep our clothes in our wooden drawers, all without thinking twice about it. However, even if we assembled it ourselves from IKEA, we did not actually make the furniture. Before buying our big wooden armoire in stores, someone had to have potentially risked their lives to make it. It may seem hard to believe, but the wood dust produced in sawmills, furniture-making, cabinet-making, and carpentry industries is highly correlated to cancer and can leave workers with DNA damage.
Wood dust is not just like the dust that collects under our beds. It is created when machines or tools are used to cut or shape wood materials. When one inhales wood dust, the dust particles are deposited in the nose, throat, and other airways.
In 1968, the first investigation linking cancer and wood dust was published. The investigation indicated that workers in the furniture industry have increased rates of nasal cancer. These findings were confirmed in several subsequent studies and finally led to the classification of wood dust as a human carcinogen by the International Agency for Research on Cancer. Research has shown that sinonasal cancer has been associated with hardwood dust. However, softwood dust can potentially be a problem as well. A recent study found that sinonasal cancer risk was increased among workers that were exclusively exposed to softwood dust. The main difference between hardwood and softwood is that hardwood is derived from the deciduous broad-leaved flowering species of trees. Softwoods include the coniferous species that do not shed their leaves in the winter.
Additionally, studies have proven that there is a carcinogenic risk with composite wood. Composite wood is a mixture of several components that may include wood, plastic, and straw. In a study involving woodworkers in Switzerland, it was disclosed that DNA damage was greater in the group exposed to composite wood products compared to the group exposed to natural woods and controls. In this same study, nasal and buccal cells were extracted from the woodworkers to identify micronuclei frequency. Micronuclei assays determine the level of exposure and health risk. The cell samples showed that the micronuclei frequency in nasal cells and buccal cells in exposed workers was significantly higher.
Moreover, composite wood is also known to emit formaldehyde which can cause adverse health effects. The carcinogenic activity of formaldehyde is supposed to be oxidative stress-mediated. Oxidative stress is caused by an imbalance between the producing and storing oxygen reactive species in cells and tissues as well as the power of a biological system to detoxify these reactive products. In a study involving woodworkers from four different factories, the results showed that woodworkers were exposed to significantly higher amounts of wood dust and formaldehyde as compared to controls. The study confirms that wood dust and formaldehyde may induce oxidative stress in woodworkers and highlights that even compliance with occupational exposure limits can result in measurable biological outcomes.
The clear link between DNA damage and sinonasal cancer begs us to ask the question: what can be done to make sure woodworkers are not exposed to the detrimental effects of wood dust?
Effective February 10, 2017, the Environmental Protection Agency (EPA) issued a final rule to implement the Formaldehyde Standards for Composite Wood Products Act.This final rule included formaldehyde emission standards applicable to all wood-containing products that are sold, supplied, or manufactured in the United States. Furthermore, the exhaust hood’s poor design is oftentimes the reason for higher levels of dust concentration near woodworking machines. The level of air dust depends on the setup of the dust extraction system. The upper hood is a crucial element of the local exhaust ventilation system, and proper construction and connection is necessary to maximize safety. The care for the proper operation of the dust exhaust system is critical because it removes the primary cause of dustiness.
Finally, the United States Department of Labor stated that protective equipment is necessary to reduce exposure to wood dust. However, personal protective equipment is less effective because it eliminates the effects of dust dispersion. It is therefore necessary to educate on the principles of design and operation of dust exhaust systems in the wood industry to properly use their capabilities.
Although wood dust exposure is dangerous, it is also limited to intense exposure such as in factories. Woodworkers still need to be kept safe and, to do so, they need proper ventilation. Hopefully, factories, sawmills, and other wood furniture-producing facilities, will implement better safety practices, and when new studies will be conducted, they will reveal little to no risk of genotoxicity.
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Sources:
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He, Z., Xiong, J., Kumagai, K., et al., 2019. An improved mechanism-based model for predicting the long-term formaldehyde emissions from composite wood products with exposed edges and seams. Environment international, 132:105086.