Abstract
This study evaluated two air sampling methods for monitoring the level and the variability of a painter's exposure to HDI polyisocyanates while spraying Tolonate-based paints in typical autobody repair shop paint booths. Personal air samples were collected by midget impingers containing 1-(2-methoxyphenyl)piperazine (MPP) absorber solution and MPP-impregnated filters. HDI biuret and isocyanurate, the principal polyisocyanates in Tolonate paint systems, were analyzed concurrently by two different laboratories. Potential exposure to HDI polyisocyanates measured by impinger devices ranged from 0.25 to 3 mg/m3. Impregnated filters significantly underestimated atmospheric concentrations of HDI polyisocyanates in the painter's breathing zone. The use of an appropriate half-face mask with 90% efficiency was recommended, since it reduced the residual exposure well below the STEL (1 mg/m3) now proposed in a few countries and recommended by manufacturers of polyisocyanates.