Gino Hagenkotter, an inmate at the Riverside Correctional Facility, was on work detail at an orchard outside the Philadelphia Industrial Correctional Center when he walked off without permission around noon, according to the city Department of Prisons.
All of Philadelphia's prisons have since been placed on lockdown, they added.
Hagenkotter, 34, was serving a sentence for theft and burglary, was a "minimum custody" inmate, and met the criteria to do work outside the prison, officials said.
Authorities said anyone who spots him should call 911.
Hagenkotter is the third inmate to have escaped from PICC this year. On May 7, homicide suspects Nasir Grant and Ameen Hurst broke out after allegedly cutting a hole in the recreation yard fence.
Grant was arrested on May 11 while Hurst spent 10 days on the run before US Marshals captured him on May 17, Daily Voice reported.
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