Chromate Content Bias as a Function of Particle Size in Aircraft Primer Paint Overspray

Spray painting operations using chromate-containing primer paints produce particles which may expose workers to strontium chromate. Chromate contains hexavalent chromium (Cr(VI)) which is a confirmed human carcinogen. It is suspected that the smaller particles contain disproportionately less Cr(VI) than larger particles. In order to determine if a bias in chromate content exists, paint particles were collected and separated based on particle size and the Cr(VI) concentration was determined. Aviation primer paint from the DeSoto and Deft companies was sprayed in a booth and seven-stage cascade impactors were used to separate particles. The particles were grouped into fourteen distinct bins based on size within an overall range of 0.7 to 34.1 um mass median aerodynamic diameter. The total mass of dry paint collected in each bin was quantified and the paint was analyzed for Cr(VI) mass.