It took the combined efforts of many federal, state, and local agencies in Florida to bring charges and obtain a conviction against Carnival. Customs piece of the investigative puzzle was to acquire entry and departure data to establish a pattern for fifteen of Carnival Cruise Line's ships.

Senior Special Agent George White, Specialist in Environmental Crimes, Miami, developed a spreadsheet, which compared information obtained from Customs forms 1400 and 1401 (Vessel Arrival and Vessel Departure), for fifteen major ports of entry used by the Carnival Cruise ships. This included the name of the vessel, the last (foreign) port of call, homeport, and departure and arrival dates.

Says SS/A White, "This information provided a pattern for each vessel and allowed the task force to target certain ports and obtain necessary documents for a specific time frame, rather than a global search. This, together with other intelligence information, led to the prosecution and conviction of Carnival."

Cruise ships sailing in the United States and international waters must operate in compliance with the laws and regulations that protect the environment. On numerous occasions from 1996 through 2001, ships owned by Carnival discharged oily waste into the sea from their bilges by improperly using pollution control prevention equipment.

The ships' bilge area, the lowest part of the hull, collects water and waste from the ship's operations. This bilge waste, which includes waste oil, must be handled so that it does not present a fire or other safety hazard. Carnival's ships typically dispose of oil contaminated bilge waste by discharging it at sea or off-loading it back at port. In order to comply with environmental laws, these ships must use pollution prevention equipment if they are going to discharge the waste at sea. The ships must also record all disposal of oily bilge waste in oil record books.

Oily bilge wastewater can only be discharged at sea if it has gone though an Oily Water Separator and an Oil Content Meter. The separator does just that: it separates the oil from the wastewater. A sample of the water then passes through the Oil Content Meter, which measures the oil content in the bilge water. The water can be dumped at sea if it contains less than 15 parts per million (ppm) of oil. Any water with more than 15 ppm of oil cannot be discharged overboard; it must be disposed of back on shore.

Carnival's negligence began when several of its engineers intentionally flushed clean water through the sensors of the meter and flushed the oily wastewater overboard ignoring the legal 15 ppm oil content limit. On one occasion, test samples of bilge waste dumped overboard from the cruise ship Sensation indicated that the waste contained 104 ppm, seven times the legal limit. The engineers also entered false notations in the oil record books that clean bilge waste had been discharged overboard. This allowed Carnival Corporation to save millions of dollars that should have been spent to properly dispose of the oily bilge waste.

In a plea agreement filed in federal court in Miami, Carnival Corporation agreed to pay a $9 million fine. This was the largest criminal fine ever imposed on a cruise line operator for environmental violations in a district. An additional $9 million will be paid as court ordered community service to various groups to fund environmental projects, initiatives, emergency response, and education dedicated to the preservation and restoration of the environment and ecosystems in South Florida.