The State Ports Authority is going on the offensive in the growing debate about pollution from cruise ship operations in downtown Charleston.

The state maritime agency announced during its board meeting Wednesday that measures are coming to lessen cruise ship emissions at Union Pier Terminal, but so-called shoreside power may not be an immediate option.

SPA chief executive Jim Newsome announced that the Carnival Fantasy will be outfitted with air-pollution scrubbers when the vessel goes into dry dock in October 2015.

The scrubbers are designed to reduce sulfur dioxide, with filters to trap soot.

Also, the SPA will ask the state Department of Health and Environmental Control to add an air-quality monitor at its Union Pier Terminal, where the Fantasy is home-ported.

"Because these questions persist and because we are wanting to be reasonable in this area, we are going to work with DHEC to see if we can, at our expense, install (an air monitoring) system at Union Pier Terminal to measure the actual impact of the vessel engines," Newsome said.

Environmentalists and neighborhood groups have complained about pollution in the historic district coming from cruise ships idling their engines at Union Pier. Most complaints target the Fantasy, which is based in Charleston year-round.

The Fantasy now must run its engine to generate electricity while in port, triggering calls for the SPA to force vessels to generate power with a shoreside outlet. The 25-year-old Fantasy, the oldest ship in Carnival's fleet, would have to be retrofitted for shoreside capabilities. In 2011, the SPA estimated that Carnival would have to spend about another $1.5 million to retrofit the Fantasy.

"The measure is not needed today," Newsome said of shoreside power.

He added Wednesday that the Fantasy's exhaust comprises 0.05 percent of total pollutant emissions in Charleston County. He said the Fantasy began burning low-sulfur fuel during port stays in Charleston in December 2013, although international law does not require reductions in sulfur content to 0.1 percent until 2015.

The scrubbers are part of Carnival's agreement with the federal regulators to reduce air pollution for nearly a third of its cruise ships. The agreement calls for Carnival to install scrubbers on as many as 32 ships over the next three years. The price tag is estimated to be $180 million.

If the technology does not meet or exceed the international standard, as Carnival expects, the company will have to resort to a more expensive solution, lower sulfur fuel.

Newsome's announcement about enhancements to the Fantasy and air monitoring comes as some political momentum is building for shoreside power.

State Reps. Jim Merrill and Leon Stavrinakis have sought authorization of up to $5 million to install the necessary equipment at the passenger terminal at Union Pier.

Merrill, R-Charleston, and Stavrinakis, D-Charleston, both serve on the House Ways and Means Committee. They said Tuesday that the committee approved the funds, meaning it will be included in the proposed budget that will be sent to the House for a vote. Charleston City Council will vote Tuesday on a resolution in support of adding shoreside capabilities at the cruise terminal.

The resolution was introduced by Councilman William Dudley Gregorie, who has previously voiced support for efforts to improve air quality in the downtown area.

On Wednesday, Newsome's nearly 20-minute presentation about Carnival Fantasy and emissions was before an audience that included Charleston Mayor Joe Riley and several City Council members.

Following the presentation, Riley said it would be good to have Newsome present the same information to the full council on Tuesday.

Riley said the air monitoring should be done before approving shoreside power.

"I think it should be installed when needed," he said, "when it proves direct environmental benefit and it's cost effective."

He added: "Before you ask for a huge capital investment to be made, allow the entity that you are asking to make the investment the opportunity to study the degrees which it may be needed."

Several City Council members, including Dean C. Riegel and Aubry Alexander, questioned if it would be premature to approve the shoreside power resolution.

"My feeling on this is, why is it necessary at this time," Alexander said.

Council members asked Newsome and other SPA officials how they feel about the proposed resolution in support of shore power.

The SPA officials said they simply didn't want to be bound to only one technology.

"Any support from City Council is useful in the context that Representatives Stavrinakis and Merrill also take time to note that the other emission-reduction strategies that are just as effective," said Barbara L. Melvin, SPA's senior vice president of external affairs. "So I think that they are not taking shore power off the table, but not limiting the application to just shore power."

Gregorie, who did not attend SPA's presentation, said he will keep his resolution for a vote on Tuesday.

"I applaud them on scrubbers, but everyone knows that will not maximize getting rid of pollution," he said. "I think shore power, plus scrubbers will make our environment safer."

The Coastal Conservation League agreed, saying scrubbers would work best if shoreside power was added to Union Pier.

"Despite today's announcement, while Carnival is experimentally retrofitting certain cruise ships with scrubbers, the EPA anticipates that these measures will have no impact on nitrogen oxides and are uncertain if there would be any reductions in harmful particulate soot or global warming gas emissions," said Katie Zimmerman, league program director. "Available evidence indicates that shore power would reduce more pollution than filters or fuel switching."

Last year, the Charleston-based group released a study that concluded that hooking a cruise ship to a shoreside power source would cut toxic emissions by 19 percent to 90 percent, depending on the type of fuel the vessel burns.