Magnesium dust poses a serious hazard because of its explosive properties.

• A. True
• B. False
• C. Not hazardous
• D. Only when wet

Answer: (A)

Fine magnesium dust can form explosive dust clouds in air. When metal is finely divided, the surface area is huge, so it oxidizes and burns extremely quickly once an ignition source is present. In welding and grinding operations, magnesium can create a suspended dust cloud that can ignite from sparks, hot surfaces, or static electricity. If ignition happens in a confined space, the rapid combustion can cause a dust explosion with a dangerous pressure rise. So the hazard is real even in dry conditions, not just when wet. That’s why the statement is true.