The three most significant health hazards are those which relate to:
It’s generally agreed upon that dust is the most serious health hazard in abrasive blasting operations.
Dusts result from:
• Broken-down abrasives
• Pulverized surface coatings
• Encrusted substances
• Abraded material from the object being blasted
The solid particles which comprise the dusts range in size from less than one micron (1/25,000 inch) to more than 1000 microns. Under normal conditions, dust particles of 10 microns or more in diameter, settle relatively quickly. Dust particles smaller than 10 microns remain airborne longer and are easily inhaled. Smaller dust particles often settle in the lungs and sometimes small soluble particles dissolve into the blood stream. The paramount hazard in abrasive blasting is from dust inhalation. All dusts are by no means equally toxic, nor are they equally respirable. The dusts of major concern are those of aerodynamic size (less than 5 microns) that are pulmonary fibrosis producing (for example sand and granite), friable reaction producing (for example copper and zinc, the components of brass), or systemic poisons (for example lead or cadmium). Dusts of larger size which fail to reach the alveoli, nuisance dust and inert dusts, such as marble and alumina are of lesser concern. The nature of the dust generated in any blasting process is the sum of the fragmentation of the blasting media and the material dislodged from the surface blasted. Where a friable abrasive media, such as sand, cobs, or beads is used, or where a friable surface, such as a sand casting, a painted or scaly surface, or masonry is blasted. the dust generated is greatly increased. Where durable media, such as steel shot, is blasted at a relatively clean surface, such as cold rolled steel, the dust generation and resultant degree of hazard is minimized. Unfortunately, for economic and practical operational reasons, many processes require friable abrasives to produce the desired degree of cleanliness or surface finish.