The health and safety problems in the forestry and lumber industries are covered elsewhere in this Encyclopaedia. This article will deal with wood as it arrives from the mill and is used in carpentry and the making of furniture and other articles. These activities are predominantly performed in small enterprises. Many workers in these industries are individual contractors and, therefore, not listed as employees, and large numbers of individuals are exposed in do-it-yourself projects and in-home workshops. This means that many of the workers involved are inadequately trained and are supervised poorly or not at all, while proper safeguards and protective equipment are often lacking.

Ahman and colleagues (1995a, 1995b, 1996) call attention to the exposure of teachers of industrial arts and woodworking in Sweden. In contrast to unexposed controls, these teachers had notable (but mainly reversible) nasal effects and complaints that increased with the number of classes from the beginning of the week and receded over the weekends, even though the dust concentrations were below the Swedish threshold limit of 2 mg/m³. In several establishments in the Netherlands, dust levels regularly exceeded that limit, and during sanding operations in a furniture factory, almost all exposures were over the local threshold limit of 5 mg/m³ (Scheeper, Kromhout and Boleij 1995).

Accidental Injuries

The most common health problem in the wood and woodworking industries is accidental injuries. These are more frequent among younger, inexperienced workers, and, for the most part, they are relatively minor. On occasion, however, they may involve long-term impairment or loss of an extremity. They include: splinters, which may become infected, and lacerations, gouges and amputations resulting from improperly used or inadequately guarded woodworking machinery (Ma, Wang and Chou 1991); sprains and strains from injudicious lifting or working in an awkward position (Nestor, Bobick and Pizatella 1990); repetitive motion injuries involving the hand or shoulder; and eye injuries. Many if not most of these can be prevented by proper training, the judicious application of machine guards and restraints and the use of personal protective equipment such as gloves and safety glasses. When they occur, prompt removal of splinters and prevention of infection by expeditious cleansing and first aid treatment of wounds will minimize disability.

Wood Dust

Wood dust exposure occurs whenever wood is sawed, chipped, planed, routed or sanded. The effects vary with the intensity and duration of the exposure and the size of the particles. Particles in the eyes may cause irritation, and wood dust gathering in skin folds may be aggravated by perspiration and chemicals and lead to irritation and infection. These effects may be reduced by vacuum removal of the dust, protective masks and clothing and good personal hygiene practices.

Nasopharyngeal and respiratory passages

Wood dust in the nasal passages may diminish mucociliary clearance and impair olfactory sensitivity (Andersen, Solgaard and Andersen 1976; Ahman et al. 1996). These may lead to irritation, frequent sneezing, nosebleeds and infection of the sinuses (Imbus 1994).

Exposures in a furniture factory (Whitehead, Ashikaga and Vacek 1981) and in sawmill workers (Hessel et al. 1995) were shown to be accompanied by decreases in both 1-second forced expiratory volume (FEV₁) and forced vital capacity (FVC), adjusted for age, height and smoking. These were accompanied by significant increases in shortness of breath and wheeze with chest tightness and the occurrence of bronchitis and asthma. There is, however, no convincing evidence of other lung disease due to wood dust exposures (Imbus 1994). In a 6-year prospective follow-up study of approximately 350,000 males in the United States, the 11,541 individuals who reported having been employed in wood-related occupations had a lower relative risk of mortality due to non-malignant respiratory disease than those who did not report exposure to wood dust (Demers et al. 1996).

Allergy and Asthma

Some woods, notably teak, mansonia and radiata pine, contain chemicals that are irritants (see table 1 for an extended list of wood species, their geographic origins, and their health effects). Some species may cause allergic contact dermatitis (e.g., Douglas fir, western red cedar, poplar, rosewood, teak, African mahogany and other “exotic” woods). Western red cedar, rosewood, mahogany and other exotic woods have been shown to cause asthma (Imbus 1994).

Cancer

An unusually high incidence of nasal cancer has been described among woodworkers in Australia, Canada, Denmark, Finland, France, Italy, the Netherlands, the United Kingdom and the United States (Imbus 1994). A recent pooled re-analysis of 12 case-control cohort studies conducted in seven countries confirmed a high risk of nasopharyngeal cancer among woodworkers (Demers et al. 1995). The cause of these excesses of nasal cancer is not known, but, according to recent reports from the United Kingdom and the United States, the risk of nasal cancer among furniture workers has declined since the Second World War, presumably reflecting changes in the manufacturing process (Imbus 1994). No excess risk of sino-nasal cancer was found among the 45,399 men exposed to wood dust included among the 362,823 men enrolled in the American Cancer Society’s 6-year Cancer Prevention Study, but, the researchers note, the number of cases was small. They did, however, find an especially high increase in lung cancer mortality among woodworkers who also reported exposure to asbestos or formaldehyde, and suggested that exposure to these known carcinogens was responsible for the observed increased risk (Stellman et al., in press).

Chemical Exposures

Wood may contain biological contaminants. Moulds and fungi, which often grow on the bark of trees, may cause allergic reactions. Inhalation of fungal spores found on maple, redwood and cork trees has been shown to cause maple bark disease, sequoiosis and suberosis (Imbus 1994).

Wood often contains exogenous chemicals applied in the course of its processing. These include adhesives, solvents, resin binders, insecticides and fungicides, waterproofing compounds, paints and pigments, lacquers and varnishes. Many of these are volatile and may be emitted when the wood is treated, heated or incinerated; they are also conveyed as elements in wood dust. The most important of these include: toluene, methanol, xylene, methyl ethyl ketone, n-butyl alcohol, 1, 1,1-trichlorethane and dichloromethane (EPA 1995).

Conclusion

Health hazards of the wood and woodworking industries may be controlled by installation of engineering controls (e.g., proper placement and guarding of power machinery, ventilation systems to control wood dust and chemical emissions) and personal protective equipment (e.g., gloves, safety glasses, respirators), coupled with periodic inspections to ensure that these are properly maintained and used. Perhaps most important is appropriate education and training of the workers and their supervisors.

Table 1. Poisonous, allergenic and biologically active wood varieties

Source: Istituto del Legno, Florence, Italy.

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