SPRINGFIELD — More than 200 employees of the Southern Illinois University School of Medicine are crying foul over a move by school administrators to strip the workers of their union affiliation.

In a protest Friday at the school's capital city campus, more than four dozen former members of the American Federation of State, County and Municipal Employees union said the university pulled a "sneak attack" when it reclassified their jobs as non-union earlier this week.

The dispute is rooted in what AFSCME says was a mix-up in a recently approved contract in which nine job titles were left out of the final draft.

Lisa Hensley, vice president of AFSCME Local 370, said union negotiators thought it was a change that later would be corrected.

"We assume it would be cleaned up," said Hensley, an office manager. "They decided to pull a fast one on us."

In a statement, Southern Illinois School of Medicine Human Resources Director Penny McCarthy said the school proposed removing two job titles during the contract bargaining process.

"The union rejected the proposal from the school and did not propose an alternative. After the agreement was fully executed, the school notified employees of the change in representation, due to their specific classification not being listed in the contract," the statement noted.

"SIU School of Medicine bargained in good faith and is abiding by the language of the negotiated agreement, which was ratified by the union," McCarthy added.

AFSCME staff representative Eric Hostetter said school administrators should have sought approval for the changes from the Illinois Education Labor Relations Board.

"They've got to go through a legal process to do this," Hostetter said.

Among those affected by the change are office workers who handle insurance claims, billing and collections. In all, 240 of the bargaining unit's 650 members are at odds with the university over the changes, Hostetter said.

The dispute affects only workers at the university's school of medicine.

Employees have filed grievances with the university in hopes of reversing the decision.