The Chicago Firefighters Union Local 2 is making a renewed push to increase retirement benefits for 2,200 of its members at a heavy cost to taxpayers: $18 million the first year and $30 million every year after that.

The bill was introduced by state Rep. Robert Martwick, D-Chicago, a political nemesis of Mayor Lori Lightfoot, before Martwick was appointed to the Illinois Senate to fill the vacancy created by the retirement of state Sen. John Mulroe.

It would remove the “birth date restriction” that has prohibited roughly 2,200 active and retired firefighters born after Jan. 1, 1966 from receiving a simple, 3% annual cost of living increase. Instead, they get half that amount — an annual increase of 1.5% that is not compounded.

On the eve of a committee hearing on the bill, Martwick noted that the “birth date restriction” has already been moved five times as a way of masking the true cost to a firefighters pension fund with roughly 25% of assets to meet its future liabilities.

“Remember, they have traditionally given that 3% simple COLA [Cost-of-living adjustments] to these firefighters. They’re going to get that. This just writes it into law. It’s really not adding cost. It’s making that cost transparent,” Martwick said.

“If we don’t change the provision and we give them the more generous, 3% simple COLA, then payment on the back end will be enormous. There’s no doubt that would make the mathematical calculation of their payment go up. But what it will do is prevent us from kicking the can and making a huge disaster down the road. It’s making the law comply with what the actual practice is.”

Rob Tebbens, political director for Local 2, referred to it as a “transparency bill” that would end the city’s longstanding practice of “fooling themselves” by “masking” the true cost of firefighter pensions.

“This is potentially an age discrimination issue because you’re basing the benefit off of an individual’s age and not their years of service. Based on their age, they’re gonna get a benefit that is less than a Tier 2 benefit” for employees hired after Jan. 1, 2011, Tebbens said.

“By law, that’s something they could possibly take to court and litigate. Doing it legislatively could save the city money in the long run. They wouldn’t have to litigate this issue.”

The mayor’s office argued that the bill would add “anywhere from $18 million to $30 million” in added costs to a pension liability imposed on Chicago taxpayers that is already scheduled to rise by $1 billion by 2023.

“While we are at the collective bargaining table working on a fair contract that supports our first responders, the administration is opposed to HB 2451 and we have shared our concerns about the serious impact it would have on our city finances with Local 2 as well as the sponsors,” the mayor’s office statement said.

“It is also unseemly that this matter is being rushed through the committee process to further the political aspirations of one person running for union president. While we strongly believe that our first responders deserve to be fairly compensated for their service, it has to be in a manner that reflects fiscal prudence.”

Tebbens, who is a candidate for president of Local 2, was asked where the city would find that kind of money.

“The city has a revenue source with the casino. This is an opportunity for the city — pun intended — to throw their cards on the table,” Tebbens said.

“They need to throw their cards on the table, show the true liability of this benefit and not mask it with this birthday rule and let the taxpayers know what the true liability is. This is not a benefit enhancement. This is just a reconciling of benefits to the members of my department.”

Last year, Martwick and Lightfoot famously got into a shouting match at a campaign news conference Lightfoot called to denounce Martwick-sponsored legislation that would change the Cook County assessor post from an elected to an appointed position.

Martwick had endorsed County Board President Toni Preckwinkle over Lightfoot in the mayoral race. Martwick also earned the mayor’s ire for championing an elected school board bill that would divide the city into 20 districts.