Coast Guard launches criminal investigation into MSC Poesia cruise ship over potential "magic pipe"

The MSC Poesia cruise ship, which was cleared to depart the Port of Miami on Thursday after being detained earlier this month, is under investigation for allegedly discharging oil illegally at sea, according to a U.S. official familiar with the probe.

The U.S. Coast Guard launched the criminal investigation into a so-called "magic pipe" case, in which a ship transfers its oil discharge into its gray water system. This is illegal under federal law.

Gray water — which includes anything from a sink or shower — can be discharged at sea as long as the ship is a safe distance from the shore.

The investigation could target crew members, the owner of the vessel, and whoever may have been directly involved and therefore potentially criminally liable, according to the U.S. official. 

CBS News has reached out to MSC Cruises, which operates the ship, for comment.

The MSC Poesia was detained at the Port of Miami earlier this month after the U.S. Coast Guard, which has jurisdiction to inspect foreign-flagged vessels entering U.S. ports, "identified deficiencies with systems on board the vessel." At the time, MSC Cruises described the issue as a "regulatory matter" and no further details were provided.

More than 2,000 people were on board the MSC Poesia at the time of its detention, a source familiar with the matter told CBS News.

Using a so-called "magic pipe" could lead to hefty fines.

In 2016, Carnival's Princess Cruises was ordered to pay a $40 million fine for dumping oily waste into the ocean. It was the largest penalty of its kind at the time. The company also pleaded guilty to seven felony charges.