On the contamination of ambient air by preparations carried out with a band-saw.

The aim was to evaluate contamination by bone-dust and formaldehyde when using a band-saw for preparations of the base of the skull and the cervical vertebral spine (stationary band-saw, 1400 upm, saw blade with 160 saw teeth/m; distances 19-26 cm, time intervals 55-90 s). The asservation of bone particles was done with adhesive microscopic slides and calcium-specific staining by alizarin-red. The quantification of air contamination was carried out with micrometry and a particle-counter. Dräger-tubes 0.2/9 were utilized for estimation of formaldehyde. The band-saw did not produce high amounts of bone-dust with suspension power. Nevertheless, 75% of the particles ranged below 5 microns in size and were respirable. Contamination decreased with an increasing height above the floor. A massive flow of particles was observed during the first minutes of sawing. The bone-dust spread some metres away. The formaldehyde levels ranged throughout between 0.5 and also over 5 ppm (MAK = 0.5 ppm). This fact makes clear an intensive contamination of the air. Therefore, a ventilation directed to the floor is necessary when a band-saw is used, as well as breathing masks and safety-goggles.