Royal Caribbean Cruises, the world’s second largest cruise line, agreed yesterday to pay $18 million and plead guilty to 21 felony charges of dumping waste oil and hazardous waste at sea and lying to the U.S. Coast Guard about it. While crew members on the line’s ships were wearing “Save the Waves” buttons, workers below deck dumped oil and toxic chemicals in New York Harbor, Alaska’s Inside Passage, and waters around Miami, Los Angeles, and the Virgin Islands. Just two years ago, the cruise line plead guilty to nine counts, paid $9 million in fines, and promised to stop polluting.