CHICAGO (CBS) — One of Mayor Rahm Emanuel’s top Chicago Labor allies is clashing with him over the new janitors’ contract at O’Hare International Airport.

WBBM Newsradio Political Editor Craig Dellimore reports on Friday, several O’Hare custodians are set to lose their jobs, after the current contractor, Scrub Inc., is replaced by a new company, United Maintenance.

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Although United Maintenance offered current janitors a chance to apply for new jobs with them, not every custodial worker was able to get a position with the company.

Chicago Federation of Labor President Jorge Ramirez said the mayor should rebid the airport janitors’ contract. Labor leaders have criticized the new deal because the current union janitors will be replaced by non-union workers, many of whom will be paid lower wages.

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Ramirez and Emanuel have worked together on other labor issues – including health care and labor agreements at McCormick Place and elsewhere – but he blasted the Emanuel administration’s pact with United Maintenance, which would lead to layoffs for current janitors and lower wages for many of the jobs it creates.

“You know, our job is very simple: I fight for working men and women. I fight for a strong and robust middle class. When that’s put in jeopardy, I come out. It’s that simple,” he said.

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Ramirez said didn’t expect Emanuel to take offense now that they’re at odds on this one.

“Why would he? I represent workers. It’s clear. I’ve never hid from that. It’s my responsibility to represent workers,” he said. “Workers are in harm’s way. It’s my duty to help, and this is what I’m doing.”

Emanuel said he respects Ramirez, but he believes the contract is a good one.

“We have a disagreement on this issue, and that’s okay,” he said. “There will be places where we agree or disagree. I have never ever lost my fight on behalf of working families, whether it was to create the Earned Income Tax Credit, expand it, double it.”

The mayor stressed some of the new janitors being hired are being given better health benefits than the current workers. The company has also said some of the new jobs pay better wages than the current janitors make.

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Other labor groups have also called for the O’Hare contract to be rebid, because of the layoffs and lower wages that would result from the deal. There also have been revelations that both United Maintenance’s owner, and a top executive at the firm’s parent company have mob ties.