Two seafarers are facing jail time in the US after admitting pollution offences on a Greek tanker.

The Newark district attorney’s office said the chief engineer of operator Avin International’s 50,000-dwt MR Kriti Ruby (built 2008) pleaded guilty to charges relating to the discharge of oily waste into the sea near a petroleum terminal in Sewaren, New Jersey.

Konstantinos Atsalis, 57, and a second engineer, Sonny Bosito, 54, also admitted concealment of pollution through the falsification of records, US attorney Philip Sellinger and assistant attorney general Todd Kim said in a statement.

US District Court judge Esther Salas heard that Atsalis admitted the tanker’s crew had knowingly bypassed required pollution prevention equipment by discharging the waste from the engine room through its sewage system.

Atsalis also said he falsified the vessel’s oil record book.

The court heard that the chief engineer had directed crew members to hide equipment used in the operations before US Coast Guard (USCG) officials boarded.

Bosito also admitted to concealing the discharge of oily waste by causing a false oil record book to be presented to USCG personnel, as well as asking colleagues to conceal equipment.

The date of the offences was not given.

The attorney’s office said the charges carry a maximum jail term of six years, plus a fine of $250,000, or twice the gross gain or loss resulting from the offence, whichever is large.

Sentencing was scheduled for 22 October.

Sellinger and Kim credited “special agents” of the US Coast Guard investigative service for the probe’s success.

Avin International has been contacted for comment.