The Fulton County Jail in northwest Atlanta is overcrowded once again, with more than 500 inmates over capacity, and some inmates have been sleeping on mattresses on the floor.

Chief jailer Mark Adger says the jail has room for 2,500 inmates, but it’s currently holding more than 3,000, the Atlanta Journal-Constitution reports. The average daily population for the system has been well above the limit since the year started.

County manager Dick Anderson recently told county commissioners that the numbers were “truly beyond” what the capacity should be. About 180 inmates at the Rice Street jail were sleeping on mattresses on the floor in open areas, he said.

About a third of the jail’s inmates are from Atlanta. Officials there decided last month to close the city’s detention center after eliminating cash bonds for poor and nonviolent offenders. However, more such defendants end up in county jail after missing court dates.

The county is considering seeking an injunction to prevent more Atlanta inmates from being sent to the county.

Also contributing to the overcrowding is the fact that the county is holding inmates for longer periods of time, after some were released on bond and committed more crimes. About 380 inmates have been awaiting trial for more than a year, Anderson said.

The county manager’s office is investigating the sources of overcrowding, but no measures have yet been taken to reduce the population, Adger said.

The population uptick undermines years of efforts and billions of dollars spent to improve conditions at the jail, the paper reports.

Overcrowding put the jail under federal court oversight for more than 10 years. The oversight was lifted four years ago.

The Southern Center for Human Rights filed the original lawsuit that led to the court oversight.

Sara Totonchi, the group’s executive director, said she’s concerned that prisoners will suffer because of the overpopulation.