The annex of MARPOL regulating prevention of pollution by oil, covering operational discharges and accidental spills from ships.
Quick facts
Regulation
MARPOL Annex I
In practice
For a deck or engineer officer, Annex I directly governs the operation of the oily water separator, the 15 ppm bilge alarm, and the Oil Record Book. Every transfer, retention, and disposal of oil-contaminated bilge water must be recorded in the ORB. Port state control inspectors scrutinise the ORB in detail, looking for implausible volumes, missing entries, or entries inconsistent with pump logs and tank sounding records. False entries constitute fraud and have led to criminal convictions of masters and chief engineers in numerous jurisdictions.
Regulatory detail & full definition
MARPOL Annex I regulates the prevention of pollution by oil from ships. Its requirements cover oil tankers and all vessels with machinery spaces, prescribing construction standards such as double-hull requirements for tankers, as well as operational discharge controls. The annex prohibits the discharge of oil or oily water into the sea except within strictly defined limits — for example, oily bilge water may only be discharged at sea when the oil content does not exceed 15 parts per million, the vessel is not within a special area, and the ship is proceeding at sea.
For a deck or engineer officer, Annex I directly governs the operation of the oily water separator, the 15 ppm bilge alarm, and the Oil Record Book. Every transfer, retention, and disposal of oil-contaminated bilge water must be recorded in the ORB. Port state control inspectors scrutinise the ORB in detail, looking for implausible volumes, missing entries, or entries inconsistent with pump logs and tank sounding records. False entries constitute fraud and have led to criminal convictions of masters and chief engineers in numerous jurisdictions.
Special areas under Annex I — including the Baltic Sea, the North Sea, and the Mediterranean — have zero-discharge standards for oily water. Officers must know which special areas the vessel is operating in and ensure that only compliant methods of disposal are used. Slop tanks, oil/water separators, and port reception facilities are the permissible means of managing oily waste.