Federal environmental regulators have reached a tentative deal with Carnival Cruise Lines to reduce air pollution for nearly a third of its cruise ships, officials said today.

The agreement with the Environmental Protection Agency and Coast Guard calls for Carnival to install pollution controls on up to 32 of its ships over the next three years, officials said.

The agreement with the Miami-based cruise ships operator will include Carnival paying $180 million in the new technologies, according to published reports.

Charleston is the home port for Carnival’s Fantasy pleasure vessel, the oldest ship in the company’s fleet.

Emission changes for the 19-year-old vessel is unknown, one Carnival official said.

Jennifer de la Cruz, a spokeswoman for Carnival, said the company is still determining which vessels will get the upgrades.

Cruise ship operations have been a hot-button topic in Charleston.

Some downtown Charleston neighborhood groups and environmentalists have filed lawsuits to block the S.C. State Ports Authority from opening a new $35 million cruise terminal at the north end of Union Pier, alleging it will bring more tourists, traffic congestion and fumes to the historic district.

Check postandcourier.com for more updates.