SPRINGFIELD, Ill. (AP) — Illinois must move most of the inmates at its 100-year-old prison within less than two months because of decrepit conditions, a federal judge ruled.

The Illinois Department of Corrections said that U.S. District Judge Andrea R. Wood’s order, issued Friday, to depopulate Stateville Correctional Center is in line with its plan to replace the facility. The department plans to rebuild it on the same campus in Crest Hill, which is 41 miles (66 kilometers) southwest of Chicago.

That plan includes replacing the deteriorating Logan prison for women in the central Illinois city of Lincoln. The state might rebuild Logan on the Stateville campus too.

Wood’s decree states that the prison, which houses over 400 people, would need to close by Sept. 30 due in part to falling concrete from deteriorating walls and ceilings. The judge said costly repairs would be necessary to make the prison habitable. Inmates must be moved to other prisons around the state.

“The court instead is requiring the department to accomplish what it has publicly reported and recommended it would do — namely, moving forward with closing Stateville by transferring (inmates) to other facilities,” Wood wrote in an order.

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The decision came as a result of civil rights lawyers arguing that Stateville, which opened in 1925, is too hazardous to house anyone. The plaintiffs said surfaces are covered with bird feathers and excrement, and faucets dispense foul-smelling water.

Gov. J.B. Pritzker’s administration announced its plan in March, but even during two public hearings last spring, very few details were available. The Corrections Department plans to use $900 million in capital construction money for the overhaul, which is says will take up to five years.

Employees at the lockups would be dispersed to other facilities until the new prisons open. That has rankled the American Federation of State, County and Municipal Employees Council 31, the union that represents most workers at the prisons.

AFSCME wants the prisons to stay open while replacements are built. Closing them would not only disrupt families of employees who might have to move or face exhausting commutes, but it would destroy cohesion built among staff at the prisons, the union said.

In a statement Monday, AFSCME spokesperson Anders Lindall said the issues would extend to inmates and their families as well.

“We are examining all options to prevent that disruption in response to this precipitous ruling,” Lindall said.