Thompson Center, 100 W. Randolph St., houses a massive CTA station, with stops on several trains lines. View Full Caption DNAinfo/David Matthews

THE LOOP — Mayor Rahm Emanuel acknowledged Tuesday he was blocking the sale of the Thompson Center in the heart of the Loop until he's certain that Chicago taxpayers won't get "stuck with the tab" for rebuilding the massive CTA station underneath the state building.

"I'm not going to stick that tab on Chicago taxpayers," Emanuel said at an unrelated event to tout park and library improvements in Bronzeville. "Why would I do that to Chicago taxpayers?"

The sale of the center is contingent on the City Council changing the rules that will dictate the size of the building that will eventually replace the the three-decade-old state office building at 100 W. Randolph St.

Eleni Demertzis, a spokeswoman for Gov. Bruce Rauner, responded by saying said Emanuel was "trying to distract from the real issue — which is the city being greedy and trying to extort the state taxpayers for more money than what the property is worth."

State officials have pledged to ensure that the CTA station — which makes the property more valuable, they said — stays open.

It could cost between $80 million to $120 million to rebuild the station, Emanuel said. State officials disputed that figure, calling it inflated.

Rauner's office hopes the sale will net the state $220 million — but that would require plans be approved for a massive tower, perhaps as tall as 115 stories.

Such a tall building would not be allowed under the current rules, giving aldermen and Emanuel — Democrats who have long been at odds with the Republican governor — a veto over the effort.

Emanuel said if the Thompson Center is torn down, Chicagoans could be forced to pay for the CTA station — the busiest in the city — to be rebuilt.

Rauner has drawn Emanuel's ire for blowing a $215 million hole in the Chicago Public Schools budget as well as a bill that would change the way the city pays for pensions due to city workers.

In both cases, Rauner said state lawmakers needed to alter the state's pension system before he would consider specific fixes.

The station at Clark and Lake streets includes stops on the Blue, Brown, Green, Orange and Purple train lines. Nearly 5.5 million passengers pass through the station every year, according to the most recent CTA ridership survey released in November 2016.

A sale of the blue and red glass building designed by star Chicago architect Helmut Jahn would also spare the state from having to pony up $326 million to cover long delayed fixes.

A new development on the site could also pay up to $45 million in new property taxes, Rauner's office says.

Last week, Crain's published a letter from Illinois House Speaker Michael Madigan to Rauner, calling the governor's plan to sell the building "flawed" because his office had yet to reach an agreement with Chicago city officials.

In February, Madigan endorsed Rauner's plan to sell the Thompson Center, which is named after former Gov. James R. Thompson and opened in 1985.

Rauner first called to sell the Thompson Center in 2015, saying the 17-story postmodern office building is "ineffective," "inefficient" and "in disrepair."

Rauner has even enlisted star Chicago architect Adrian Smith to design renderings showing the potential of the Thompson Center site in the heart of the Loop.

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