What must be checked before reusing any remaining dry chemical in a discharged extinguisher?

Before reusing any remaining dry chemical in a discharged extinguisher, it is essential to check the type and condition of the chemical. This step ensures that the dry chemical is appropriate for the specific type of fire it is intended to fight and that it has not deteriorated or become contaminated. The effectiveness of the dry chemical in extinguishing fires depends heavily on maintaining its integrity and suitability.

If the type of chemical is incorrect for the classified fire hazard, or if its condition indicates that it may no longer effectively suppress flames—perhaps due to clumping, moisture absorption, or other forms of degradation—then attempting to reuse it could be dangerous and ineffective. Thus, confirming both the type and the condition directly influences the safety and success of using the extinguisher in an emergency situation.

The other factors, while they may be relevant in different contexts, do not directly address the crucial requirements for effective fire suppression in relation to the dry chemical's readiness for use.