Question 625General Subjects - Assistant Engineer

The correct answer is A) Polychlorinated biphenyls (PCBs). Under MARPOL Annex VI regulations, PCBs are prohibited from being burned in shipboard incinerators. This is because PCBs are highly toxic and persistent organic pollutants that can have severe environmental and health impacts when released. The regulations aim to prevent the incineration of such hazardous substances onboard ships. The other options are incorrect because oil residue sludges, unground garbage, and sewage waste sludges are generally permitted to be incinerated onboard, as long as the incinerator meets the applicable air emissions standards under MARPOL Annex VI.