Question 839 Deck Safety

The correct answer is C) a mattress. An "ABC" dry chemical fire extinguisher is least effective against a fire in a mattress. Dry chemical extinguishers are primarily designed to extinguish fires in ordinary combustible materials (Class A), flammable liquids and gases (Class B), and live electrical equipment (Class C). However, they are less effective against deep-seated, smoldering fires in materials like upholstery or mattresses, which require a cooling effect to fully extinguish. Other types of extinguishers, such as water-based or foam extinguishers, would be more appropriate for a mattress fire. The other options are incorrect because dry chemical extinguishers are effective against trash can fires (A), spilled liquids (B), and electrical fires (D).