While shippers will maintain their routes even if fuel prices rise, every major cruise line is rethinking whether it will need to scale back on some itineraries in order to control costs. Even the companies that have touted their environmental credentials the most — Disney Cruise Line and Royal Caribbean, for example — are lobbying the EPA to reconsider how it enforces the new rules.

Bud Darr, vice president for technical and regulatory affairs at the Cruise Lines International Association, said his members are worried whether there’s “sufficient quantity of fuel, particularly as it pertains in the Pacific Northwest” to meet the standards. While the EPA has issued guidelines on how firms can document their inability to purchase fuel, Darr said the potential shortage would spike costs.

Cruise companies have proposed that they be allowed to burn higher-sulfur fuel at some points in the 200-mile control zone while curbing emissions elsewhere.

Cruise industry officials say they may have little choice but to explore routes outside the Emissions Control Area at some points in their itineraries to save money. Princess Cruise Lines spokeswoman Juliet Benson, who noted that her company pioneered the practice of plugging into onshore electrical power while in port, wrote in an e-mail that Princess anticipates “some future changes” to its routes.

“The cost of fuel plays a key role in our itinerary planning, and we balance offering the most desirable routes for our passengers with ensuring maximization of fuel efficiency,” she said.

While the new limits will pose some challenges, Becker said that state and local officials — who lack jurisdiction over ships — need them in order to meet stricter federal air quality requirements over the next decade. “We will not be able to meet the federal health-based standards without the benefits of this program,” he said. “They’re that significant.”