Portline Bulk International must pay a $1.5m fine for using a "magic pipe" to illegally dump oily bilge water overboard and falsifying records to conceal the evidence.

The Portugese bulker operator's engineering team bypassed a supramax's oily water separator on numerous occasions with a yellow plastic hose known as a "magic pipe," according to US Department of Justice (DOJ).

The company was charged with one count of violating the Act to Prevent Pollution from Ships and one count of obstruction, according to documents filed in South Carolina federal court.

It has agreed to pay a $1.5m fine upon sentencing and will be put on a four-year probation that will include an environmental compliance plan.

“The world’s oceans are not a dumping ground for criminals who seek to evade our nation’s environmental laws,” said Assistant Attorney General Jeffrey Bossert Clark for the Justice Department’s Environment and Natural Resources Division.

From April 2017 to August 2018, chief engineer Anatoli Zotsenko made fake entries in the oil record book for the 51,000-dwt Achilleus (built 2001) to hide overboard discharges of oily bilge water.

He and second engineer Valerii Pastushenko, who had prior pleaded guilty to violating the aforementioned act, were fined $12,500.

They were also given a three-year probation that bans them from entering US ports and anchorages. They face six years in prison and a $250,000 fine if they violate probation, court documents state.

The US Coast Guard discovered the false ledger on 14 August 2018 during an inspection of the vessel in the Port of Charleston, the DOJ said.

Portline said it entered into a plea agreement with US authorities as the employer responsible for the illegal actions of the two engineers, who violated express training and environmental policies.

"The ship’s manager, Portline Bulk International, is committed to environmental integrity and has cooperated with U.S. authorities, in full, since the beginning," Portline said.

"As ever, PBI is fully committed to environmental stewardship and has bolstered its shipboard practices and auditing procedures so that this kind of misconduct can never happen again."

Portline said the ship's "ownership group" was not charged with any wrongdoing but declined to disclose the name of the owner.

The ship is owned by a "Maltese owner", according to court documents.