Mayor Martin J. Walsh refused Wednesday to disclose the terms of a tentative contract for Boston firefighters, a test for a fledging administration that swept into City Hall with the staunch support of the firefighters union while promising a new era of transparency.
“I can’t tell you,” Walsh said when pressed during an interview for details of the contract. “They are working it out with their membership. Once the contract is ratified, the public will know what’s in there.”
The practice of keeping details secret marks an abrupt change from former mayor Thomas M. Menino, whose administration routinely released specifics when the city reached tentative deals with unions. In an interview, Walsh said Menino leaked contract details to the press through an “unnamed source,” thus undercutting the negotiating process.
When Menino hammered out his last major contract, there was no leak. He held a press conference at City Hall in September 2012 with the Boston Teachers Union and both sides outlined terms before the deal was approved by union membership.
Taxpayers deserve to know details of the tentative firefighters’ contract immediately, said Samuel R. Tyler, who served on Walsh’s transition committee and is president of the Boston Municipal Research Bureau.
“This is a departure from past practice when basic information would be made available before members of the union were asked to ratify it,” said Tyler, whose fiscal watchdog is funded by businesses and nonprofits.
Public safety contracts include complex provisions — vacation packages, pay differentials, payouts for sick leaves — that take time to scrutinize, Tyler said. The extras can significantly augment pay.
Councilor at Large Stephen J. Murphy said he saw no harm in keeping details of the contract confidential.
“In good course, the City Council will do its due diligence and determine whether this is affordable,’’ said Murphy, who heads the council’s Public Safety Committee and has not seen the tentative deal. “I think the public needs to be the public. . . . The public isn’t here. And if we don’t do our jobs, they need to throw us out.”
Walsh has a particularly close relationship with the firefighters union, which clashed with Menino. The union and its affiliates spent more than $130,000 on Walsh’s election. Richard Paris, president of Boston Firefighters Local 718, appeared with Walsh at campaign stops.
Walsh, who said he attended bargaining sessions, announced the tentative firefighters’ deal Saturday with a press release that offered no details but described the agreement as a compromise for firefighters and taxpayers.
Last week, Walsh filed his first budget, a proposal that would probably require layoffs because it eliminates at least 23 positions at the Boston Public Health Commission and 69 full-time jobs at the School Department, largely from administrative offices.
On Wednesday, Walsh said the agreement marked the first fire contract since 2001 that did not require arbitration. He promised Local 718 that he would keep terms secret until the union ratifies the deal.
“I’m sticking to my word,” Walsh said. “We have a good deal on the table for the city, and we want to get this contract ratified. The taxpayers should know everything, and they are going to know everything.”
The goal of settling contracts without arbitration was one of the core promises of Walsh’s bid for mayor. He campaigned as a labor leader who would be able to get results at the negotiating table because municipal unions trusted him.
Now that Walsh is mayor, he must balance the competing interests of police and firefighters. The two public safety unions have battled for years for equal pay, with both sides using a different definition for parity. In 2013, firefighters were paid an average of $97,000, while the average police officer made $104,000, according to payroll records.
Those figures do not include an arbitration ruling that the Menino administration said would increase the average officer’s pay by more than 25 percent over six years.
The police union contends that officers’ earnings include compensation from traffic details, which are paid by private companies. The police union has said firefighters can earn more because many have second jobs. Firefighters have rejected that argument and pushed for pay equal to police.
Paris, the firefighters union president, did not respond to a phone message seeking comment.
The Boston Fire Department had a payroll of nearly $178 million in 2013. It has more than 1,400 uniformed employees, and rank and file members belong to the same union as the command staff. The union’s contract expired June 30, 2011.
Menino often battled with the union as he tried to change the department’s culture. The former mayor hired Roderick Fraser, the department’s first commissioner to come from outside the department. He also hired Steve E. Abraira, the first chief from outside the department.
The union fought both outsiders as they tried to institute changes. Abraira resigned last year after less than 18 months. Fraser left the day Walsh took office.
Walsh said the tentative agreement includes some new language, but he declined to say whether the changes are reforms. Instead, the mayor referred to the fatal fire last month on Beacon Street.
“When we talk about reforms at the Fire Department, I think the firemen and women did an unbelievable job of putting out a fire in very difficult circumstances, knowing that one of their brothers was in that building,” Walsh said. “So when we talk about reforms, I’m not going to get into a matter of criticizing our public safety officials.
“But where we need changes in the contract,” he said, “there will be those changes.”