[A "technically attainable" refernce value for exposure to wood dust in the light of Law 66/2000]

The question of appropriate exposure standards for wood dust is addressed by reference to the major health effects, especially sino-nasal cancer, that have been investigated. A review of several key papers on wood dust exposure permits some associations to be made between exposure data and effects, particularly impaired/suppressed nasal mucociliary clearance, according to which it may be suggested, based on available evidence, that a standard of 1.5-2 mg/m3 of total suspended wood dust could reasonably protect against the observed effects. Moreover, data from the literature show that reducing personal wood dust exposures to below 2 mg/m3 is accomplished relatively easily, whereas reducing exposures to below 1 mg/m3 is considerably more difficult and expensive. The exposure level of 1.5-2 mg/m3 is suggested for all wood dusts; it does not seem reasonable at the present time to distinguish between hardwood and softwood because many of the important mortality studies report results based on patients with mixed exposures. The threshold exposure value of 5 mg/m3 for hardwood proposed from 1/1/2003 by Law 66/2000 is deemed to be too high as a health-based occupational exposure limit.