PROVIDENCE, R.I. (AP) — The longtime head of Rhode Island's prison system and the longest-serving state prisons chief in the country is planning to retire.

The governor's office on Tuesday said Department of Corrections Director A.T. Wall will retire in early 2018.

Wall was appointed in 2000 and has been working in Rhode Island's criminal justice system for three decades. The announcement highlighted his work developing inmate and parolee job training programs and a medication-assisted treatment program to address the opioid overdose crisis.

Democratic Gov. Gina Raimondo (ray-MAHN'-doh) calls Wall a "treasure" and says he has dedicated his life to public service.

Raimondo's office says there will be a nationwide search for Wall's replacement. In the meantime, Assistant Director Patricia Coyne-Fague has been named acting director.