WHITTIER, Alaska — The gleaming white Sapphire Princess docked in this deep-water port this month, unloading its passengers and taking on 2,600 more guests headed first to Glacier Bay and eventually to Vancouver, B.C. Every day of that trip the cruise ship — whose website invites passengers to see Alaska’s “pristine landscapes” — will emit the same amount of sulfur dioxide as 13.1 million cars, according to the Environmental Protection Agency, and as much soot as 1.06 million cars.

But starting Aug. 1, the Sapphire Princess and every other large ship traveling within 200 miles of the coasts of the United States and Canada will have to burn cleaner fuel.

These new restrictions — which will phase out the world’s dirtiest transportation fuel in U.S. waters — represent one of Barack Obama administration’s most ambitious, and least-noticed, anti-pollution programs. But they have prompted a major counteroffensive from the cruise industry as well as several lawmakers, who argue that they will raise costs for vacationers and Alaskans who depend on oceangoing vessels for basic foodstuffs.

“This is the sleeping giant no one is paying attention to,” said William Becker, executive director of the National Association of Clean Air Agencies, which lobbied for the new rule and represents officials from state and local air agencies across the country.

For years, large ships have burned a heavy fuel with 2,000 times or more the amount of sulfur as the diesel fuel used by trucks, locomotives, construction equipment and small marine vessels.

George W. Bush’s administration proposed limiting sulfur dioxide emissions for ships in 2007; the International Maritime Organization three years later adopted the joint U.S.-Canadian proposal to create an “Emissions Control Area” within 200 miles of shore. Countries bordering the Baltic and North Sea enacted similar limits in the late 1990s.

The new rule requires large ships to cut the sulfur content of their fuel, which now averages 2.7 percent, down to 1 percent next month; in 2015 it must drop to 0.1 percent.

The EPA estimates that the new rules will avoid between 12,000 and 31,000 premature deaths each year by 2030, with the benefits outweighing the costs 95 to 1. Put another way, when the stricter limit goes into effect in 2015 it will be akin to taking 12.7 million cars off the road per day and eliminating their sulfur dioxide emissions, or the soot from 900,000 cars. Air pollutants from burning ship fuel off the Pacific Coast contribute to lung disease and affect air quality as far away as North Dakota, according to agency officials.

“These important standards will lower emissions from ships and help safeguard our port communities and cities hundreds of miles inland,” said Gina McCarthy, who heads the EPA’s air and radiation office.

The container and vehicle shipping industry, which spends less time within the 200-mile zone than the cruise industry, has indicated that it can meet the new standards. But a couple of firms serving Alaska, including Totem Ocean Trailer Express, predict their fuel costs could eventually rise 25 percent as a result.

It is difficult to get precise estimates on what the cleaner fuel will cost, in part because its availability remains uncertain. The EPA estimates that when fully implemented the program will add $18 to the cost of shipping a 20-foot container and about $7 per day to the cost of a passenger’s cruise ticket. Cruise industry analysts, however, say it could add as much as $19.46 a day per passenger. The total annual cost of implementing the rule in 2020 will be $3.2 billion, according to the EPA, weighed against between $47 billion and $110 billion in benefits.