Question 735 Deck Safety

The correct answer is D) Oxygen indicator. An oxygen indicator is the appropriate tool to measure the percentage of oxygen inside a chain locker. Chain lockers are enclosed spaces that can become oxygen-deficient due to the rust and corrosion of the chain, which can consume oxygen. Measuring the oxygen level is crucial to ensure the safety of personnel entering the space. Other devices like H2S meters, flame safety lamps, and combustible gas indicators are not designed to specifically measure oxygen concentration, making them unsuitable for this purpose.