Two of five young adult inmates are housed with older detainees — defying rules that they must be separated, the city’s jails watchdog found.

The promised end to “commingling” of young adults ages 18 to 21 with older inmates was part of a 2015 reform plan meant to acknowledge youth’s developmental needs and deliver them better programming in a designated space of their own. 

But the city Department of Correction has since backed away from its commitment to stop the practice at Rikers Island and other city lockups. 

In a Sept. 2 letter to the Board of Correction, which sets rules for the jails, DOC Commissioner Cynthia Brann called the use of commingling “a strategic determination” and “an important mechanism to promote safety.”

The share of youth in designated young adult housing has decreased to 60% since January 2020, when 71% of under-22-year-olds in city jails were in those units or special medical ones, a Board of Correction presentation made Monday showed. 

James Perrino, a board member, said that with the jail population at a low, the department should be able to keep young people in their own facility.

“It seems like we’re going in the wrong direction, and to be honest, the people that we’re taking out probably are the ones who are most needing of these programs,” said Perrino, who is a former warden and assistant chief at the Department of Correction. 

The department’s stance poses a problem for its oversight board, which has continually granted formal permission to DOC to depart from the rule. Board members did so again Monday, some with gritted teeth.

“I don’t want really to be in the same position six months from now or in a year,” Steven Safyer, a board member, said. “I would feel like we’ve failed.”