Which of the following fire extinguishing agents which may be found aboard ship is designated as an ozone-depleting substance as defined in the Montreal Protocol on Substances that Deplete the Ozone Layer and is controlled as a result?

Correct Answer: Option A — Halon 1301

Halon 1301 is a potent ozone-depleting substance controlled under the Montreal Protocol. Due to its high ozone depletion potential, its use in new fire suppression systems is strictly regulated or prohibited, and existing systems are being phased out in favor of environmentally friendly alternatives like CO2 or water mist.