CRANSTON — Vowing to ratchet up a flagging campaign against a half-built concrete batching plant off Pontiac Avenue, the leading neighborhood opposition group has forced out its president, brought in new leadership and hired a former talk radio host as a public relations specialist.

Cranston Citizens for Responsible Zoning and Development’s board of directors asked Frank Mattiucci, president of the group for the last 1½ years, to submit his resignation last month. And at a Nov. 18 meeting, it named Dennis J. DeMarco to succeed him.

DeMarco, 52, a member of the group since the summer of 2006, promised a no-holds-barred approach to the fight against Cullion Concrete Corp., the firm that owns the plant.

“It’s really time to go for the jugular,” he said, in an interview yesterday.

DeMarco said the opposition group would ramp up recruitment efforts, beef up its Web site, even press the state to appoint a special prosecutor to investigate the issuance of a building permit for the project last year, under former Mayor Stephen P. Laffey.

But it is unclear what role the increasingly hard-line advocacy group can play, at this point, in blocking completion of the controversial concrete plant.

The haggling over the project, which has drawn sharp opposition from neighbors and politicians concerned about traffic, noise and pollution, has shifted from the courtroom and political arena to closed-door negotiations.

In October, the state Supreme Court ordered the city and Cullion to enter into nonbinding mediation, to be overseen by retired Chief Justice Joseph R. Weisberger.

The two sides, facing a court-imposed gag order, have remained tight-lipped about the negotiations.

But the city, which made behind-the-scenes overtures to Cullion before mediation, is expected to offer a buyout of some kind.

And the Pawtuxet River Authority & Watershed Council, a state-chartered agency that acts as steward of the river, has been working with the city to cobble together a waterside park that would include the Cullion property.

Still, if the fate of the property seems beyond Cranston Citizens’ reach at present, the group has proven adept at keeping the concrete plant in the headlines and pressuring the mayor and City Council to fight the project.

The organization has packed public hearings, staged news conferences and planted red “Stop the Concrete Plant” signs on dozens of lawns.

But Mattiucci was not aggressive enough for some inside the group, which formed in May 1997 to fight a Pep Boys auto shop proposed across the street from the Garden City Shopping Center.

“We just decided that we weren’t hitting hard enough at this point,” said board member Suzanne Arena, adding later, “we really needed to change directions.”

Mattiucci, whose property is just 70 feet from the Cullion parcel, acknowledged a split on tactics.

The former president of the group, while sharply critical of city officials for not doing enough to stop the plant, said he was more willing than others in the organization to give the administration space to work out a solution.

“At least for awhile, it was our intention to give them some room and some time to work on the problem,” Mattiucci said.

But he argued that his ouster was really tied to a clash with the group’s lawyer, Richard E. Crowell, Jr.

“He didn’t feel he could work with me any longer,” Mattiucci said, of Crowell. “So it was him or me, and the board decided he was more valuable. So I submitted my resignation.”

Crowell, while acknowledging some differences with Mattiucci, denied that any personality clash was behind the ouster.

He said the board was concerned, among other things, about conversations Mattiucci was having with the mayor and Michael J. Sepe, chairman of the Democratic City Committee, without the board’s knowledge.

Mattiucci said he routinely made the group’s case to anyone who would listen and always informed the board of those talks. In fact, Mattiucci said, he told the board about his recent conversations with Sepe and Napolitano.

Sepe said he ran into Mattiucci at Job Lot about a month ago and proposed a meeting with the mayor, which never occurred, to iron out any differences.

“We weren’t hiding anything,” Sepe said.

And in a news release, Sepe called the newly constituted group’s call for a special prosecutor a “reckless and hysterical” proposition.

The group, he suggested, was poised to “join the leagues of ineffective fringe groups.”

But Howie Barte, a former talk radio host on WHJJ-AM recently hired by the organization, said the group will continue to pressure city officials to rid Cranston of Cullion’s plant.

And DeMarco, who has been in touch with residents who fought a now-withdrawn big-box retail proposal for the Mulligan’s Island golf complex and neighbors battling a drive-through planned for a Dunkin’ Donuts on Pontiac Avenue, said he hopes the group can eventually turn into a citywide watchdog.

dscharfe@projo.com