The captain of the tanker ship T/V Green Sky pleaded guilty to a felony count in federal court in Charleston, South Carolina, for obstructing a U.S. Coast Guard investigation into pollution crimes aboard the vessel.

Genaro Anciano, 52, a Filipino citizen and the highest ranking officer aboard the ship, pleaded guilty to one count of Obstruction of an Agency Proceeding. The charge stems from a Coast Guard investigation in late August 2015 into the bypass of pollution prevention equipment on the Green Sky. In court papers, the defendant stated that members of the ship’s engine room, including a senior officer, admitted to illegally discharging overboard. These admissions occurred prior to the August 2015 Coast Guard inspection at the port of North Charleston. During the investigation, Anciano made several false and misleading statements to the Coast Guard to cover up the illegal conduct.

The T/V Green Sky is a 30,263 gross ton, ocean-going vessel that operates as a petroleum and chemical tanker. The vessel is approximately 600 feet in length and is registered in Liberia. The vessel is owned by an entity incorporated in the Marshall Islands.

Over the course of several days, the normal operation of the Green Sky generates thousands of gallons of bilge wastes that are contaminated with petroleum products and oil residues. These bilge wastes must be removed for the vessel to operate safely.

Both the United States and Liberia are parties to the MARPOL treaty, which regulates the overboard discharge of bilge waste. It is prohibited to discharge bilge wastes from the T/V Green Sky without first running that effluent through the ship’s oily water separator. According to the MARPOL treaty, all overboard discharges from the vessel’s bilges had to be recorded in the T/V Green Sky’s oil record book. A bypass of the oily water separator, which is not recorded in the oil record book, jeopardizes the accuracy and integrity of that document. It is a separate federal crime for oceangoing vessels to enter a U.S. port with a false oil record book.

Anciano’s sentencing has not yet been scheduled.