Wood dust is one of the most common occupational dust exposures. Worldwide, approximately 13 million people were occupied in the forestry sector and about 3.5 million people in the furniture industry in year 2000. This means that about 0.4% of the total labour force were occupied in the forestry sector [1]. Recently, Kauppinen et al. [2] reported that 3.6 million workers, i.e. 2.0% of the workforce, were occupationally exposed to wood dusts in the European Union.