Health Facts

NIOSH

According to the National Institute for Occupational Safety and Health (NIOSH), table saws create a significant amount of wood dust and are known to cause health problems including cancer.
Workers exposed to wood dusts have experienced a variety of adverse health effects such as eye and skin irritation, allergy, reduced lung function, asthma, and nasal cancer.¹

Wood dust is known to be a human carcinogen, according to the National Toxicology Program. An association between wood dust exposure and cancer of the nose has been observed in many case reports, cohort studies, and case control studies that specifically addressed nasal cancer.²

1 Source: Centers for Disease Control and Prevention http://www.cdc.gov/niosh/hc10.html 
2 Source: National Toxicology Program's 10th Report on Carcinogens

Ohio State University Extension

Wood Dust Exposure Hazards— AEX-595.1-2006 (Revised)

Thomas L. Bean, in collaboration with Timothy W. Butcher and Timothy Lawrence

Wood dust is created when machines are used to cut or shape wood materials. Industries that have a high risk of wood-dust exposure include sawmills, dimension mills, furniture industries, cabinet makers, and carpenters. Negative health effects have been associated with professions that shape, cut, or work wood. Companies need to be aware of the health effects of wood dust, as well as NIOSH and ACGIH exposure level recommendations and applicable OSHA standards, and how they may affect their production facility.

The terms hardwood and softwood have no reference to the actual hardness of the wood. Hardwoods are from deciduous broad-leafed trees, and softwoods are from conifers. A significant difference does exist in the effect of the dust created during their handling. Hardwoods such as oak, mahogany, beech, walnut, birch, elm, and ash have been reported to cause nasal cancer in wood-workers. This is particularly true when exposures are high.

The American Conference of Governmental Industrial Hygienists (ACGIH) recognizes wood dust as a "confirmed" human carcinogen and recommends a limit of 1 milligram per cubic meter (mg/m3 ) for hardwoods and 5 mg/m3 for softwoods. At this time, OSHA regulates wood dust as a nuisance dust; however, OSHA strongly encourages employers to keep exposures to a minimum and to adopt the ACGIH levels. The maximum permissible exposure for nuisance dust is 15 mg/m3, total dust (5 mg/m3, respirable fraction).

Health Effects

Exposure to wood dust may cause external and internal health problems. Adverse health effects associated with wood dust exposure include dermatitis, allergic respiratory effects, mucosal and non-allergic respiratory effects, and cancer.
Allergic respiratory problems can be caused by wood dust. The chemicals in wood that are associated with allergic reactions are generally found in the inner parts or heartwood of the tree. A hypersensitivity reaction leading to asthma has been reported as a result of exposure to commonly used woods, including Western Red Cedar, Cedar of Lebanon, Oak, Mahogany, and Redwood. The asthmatic reaction is believed to be species-specific.

Dermatitis is also a common health hazard associated with exposure to wood dust. Wood, usually as sawdust or splinters, may affect the skin or mucous membranes by mechanical action or by chemical irritation and sensitization. Irritant reactions appear to be more common among lumber workers. The main population of workers who suffer from dermatitis-related problems are those who work in secondary wood product manufacturing facilities, although cases have been documented in sawmill workers.

Cancers have been associated with wood dust exposure. The National Institute for Occupational Safety and Health (NIOSH) considers both hardwood and softwood dust to be potentially carcinogenic to humans. The three types of cancers associated with wood dust exposure are nasal and sinus cavity cancer, lung and other cancers, and Hodgkin's disease. The wood and cancer relationship was studied by Milham (1974), who conducted a mortality study involving the AFL-CIO United Brotherhood of Carpenters and Joiners of America. This study supports the hypothesis that wood contains carcinogenic agents. The cancer mortality patterns found were:

• Excess lung cancer in acoustical tile applicators and insulators.

• Excess gastrointestinal cancer in pile drivers.

• Excess leukemia lymphoma group cancers in millwrights, mill workers, and lumber and sawmill workers.

• Excess lung and stomach cancer in construction workers with the greater excesses found in workers in major urban areas.

Hodgkin's disease has also been associated with wood dust. One study (Milham & Hesser, 1967), which examined 1,549 white males terminally ill with this disease, showed an association between Hodgkin's disease and wood dust exposure. Another study (Spiers, 1969) concluded that men working in wood industries in the eastern United States were at special risk for the disease, due principally to the carcinogenicity of pollen grains from eastern pine species.

Western Red Cedar occupies a particular place in hazard awareness because it contains the irritant chemical plicatic acid. Plicatic acid is most concentrated in western red cedar, but it is also found in significant quantities in eastern white cedar and japanese cedar. Plicatic acid is believed to be the causative agent in western red cedar dust-induced asthma and affects between 4 and 13.5% of exposed populations (Chan-Yeung, 1994). For additional information go to their web site: http://ohioline.osu.edu/aex-fact/0595_1.html