Friends of the Earth issued its first-ever Cruise Ship Environmental Report Card, an assessment of the environmental and human health footprint of cruise lines and ships operating in the United States.

Millions of Americans take cruise vacations every year. Travelers may not realize that taking a cruise is more harmful to the environment and human health than many other forms of travel.

“For the first time, vacationers can decide which cruise to take based on a ship’s environmental and human health impacts,” said Marcie Keever, Clean Vessels Campaign Director at Friends of the Earth. “Typically, cruise ship passengers are attracted to cruise vacations with pictures of pristine waters and promises of unspoiled scenery and abundant wildlife, but these passengers are never told that their vacation could leave a dirty mark on the places they visit. This is something travelers should pay close attention to: half of the cruise lines we evaluated earned grades of C- or below.”

Cruise ships carrying up to 7,000 passengers and crew are like floating cities that release substantial amounts of pollution into the air and water. Cruise ships have the potential to despoil the very areas they visit and passengers often ask whether there are any cruise lines or ships that are environmentally friendly.

Friends of the Earth’s report card ranks 10 major lines—Carnival Cruise Lines, Celebrity Cruises, Cunard Cruise Line, Disney Cruise Line, Holland America Line, Norwegian Cruise Lines, Princess Cruises, Regent Seven Seas Cruises, Royal Caribbean Int’l, and Silversea Cruises—according to three environmental criteria: sewage treatment technology, air pollution reduction, and water quality compliance in Alaskan waters. Holland America, Norwegian and Princess come out on top, and Carnival, Royal Caribbean and Disney are rated the worst.

An explanation of Friends of the Earth’s grading system, information about the environmental impact of individual cruise ships, and actions people can take to pressure cruise lines to clean up their act can be found at http://www.foe.org/cruisereportcard.

A PDF of the report can be found at http://www.foe.org/sites/default/files/CruiseReportCard.pdf.