When it comes to offshore pollution, the public and media tend to focus on accidental spills. But the intentional dumping of oil is a more rampant environmental problem. On average, ships purposely dump more oil into the oceans every three years than the amount spilled in the BP and Exxon Valdez accidents combined. This occurs through what is popularly called a "magic pipe." The pipe's trick is to flush toxic waste into the sea, making it disappear for a much cheaper cost than properly disposing of it on land. A particularly alarming case of magic-pipe dumping involved one of the world's largest cruise liners, The Princess Caribbean.