CHICAGO (CBS) — Hundreds of employees at the University of Illinois at Chicago Medical Center have begun a three-day strike, demanding a contract after unionizing more than two years ago.

CBS 2’s Marissa Bailey reports nearly all employees at UIC Medical Center, except doctors and nurses, have walked out over the contract dispute.

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Hospital administrators said it’s the first time a union has gone on strike at the campus.

Service Employees International Union Local 73 said they hope the strike and Wednesday’s protest rally outside the hospital send a strong message to university leaders.

SEIU local 73 represents 500 medical employees of the 3,200 employees at UIC Medical Center – with the exception of doctors and nurses.”

Almost 500 members – covering more than 60 job titles in all – have begun a three-day strike, because no contract agreement has been reached since they unionized in 2010.

“They perform an important task, day in and day out,” SEIU representative Remzi Jaos said.

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After 14 months of negotiating, UIC offered the workers a 3 percent pay increase but Jaos said it’s just not enough. Members want specific pay increases for specific job titles.

“The majority of the titles here have not seen increases in six years, so that’s not going to be good enough for this group,” Jaos said.

Occupational therapist Kathleen Jensen said, “We have people that … have worked here 15 years that are making less than new graduates right out of school.”

UIC spokesman Mark Rosati said the university has lost funding, and everyone – in every department – has to cut back.

“We’ve certainly made every effort to negotiate a contract that we think is fair, put an offer on the table that is reasonable, that is fair to our employees, and that takes into account the need for financial responsibility,” Rosati said.

Rosati said the strike has not affected hospital operations.

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SEIU members said they will be on the picket lines until 6 p.m. Friday. It’s part of what they call a “limited” strike.