Which of the following describes the residue left by dry powder extinguishers?

• A. Leftover chemical residues and dust can make cleanup difficult and damage electronics
• B. Residues are inert and harmless
• C. Residues are water-soluble
• D. Residues improve conductivity

Answer: (A)

Dry powder extinguisher residue is a fine chemical dust that can cling to equipment, wiring, and electronics. This powder can be abrasive and chemically active, so it may cause corrosion, insulation problems, or interference with contacts if it isn’t cleaned away properly. Cleaning is difficult because the dust can penetrate crevices, filters, and inside equipment, often requiring careful removal and sometimes special cleaners or vacuuming. That combination of dirtying surfaces, potential electrical or sensor problems, and the challenge of thorough cleanup is exactly what makes this residue problematic in practice. The other descriptions don’t fit because the residue isn’t simply harmless or water-soluble, and it doesn’t improve conductivity; it tends to create cleaning challenges and potential electrical issues instead.