SACRAMENTO, Calif. β€” California began identifying certain vulnerable inmates as needing special protective housing starting in the late 1990s and created so-called Sensitive Needs Yards for those inmates beginning in early 2002.

However, an Associated Press investigation found that the yards have developed their own problems, helping to push California's inmate homicide rate to double the national average.

The AP found that male sex offenders make up about 15 percent of the state's prison population but accounted for nearly 30 percent of the 78 California prison killings reported by corrections officials since 2007.

___

WHAT ARE THEY?

Sensitive Needs Yards are separate cell blocks, common areas and outdoor recreation yards set aside for inmates who would likely be harmed if they were in the general population with other prisoners. They include sex offenders; inmates with youthful appearances; inmates who have left prison gangs; have been assaulted; have enemies in the general prison population; have drug or gambling debts; or are former law enforcement or correctional officers.

___

WHO IS THERE?

California prisons hold a total of 37,457 inmates labeled as "sensitive needs," nearly 28 percent of the overall inmate population. Forty percent of the sensitive-needs inmates are registered sex offenders.

___

WHERE ARE THEY?

California has 47 of the yards scattered within 21 of the state's 34 prisons. All of them are in men's prisons. Women's prisons do not have Sensitive Needs Yards.

___

HOW MUCH DO THEY COST?

Prison officials say there is no additional cost, as Sensitive Needs Yards are run like any other housing unit.