Overcrowding caused partly by drug sentences is forcing the state prison board to invoke the Emergency Powers Act. The move authorizes the early release of a projected 569 inmates over the next three months. Prison spokeswoman Dina Tyler said a burgeoning prison population prompted the state Board of Corrections to invoke the act, as it has every 90 days since November 1998. The move enables the prison system to set free early those parole eligible inmates who are within 90 days of release. The prison population currently stands at 11,067 males, 89 inmates over capacity, and 759 females, 97 over capacity. Also, 873 state prisoners are being housed in county jails awaiting room in the prison system. Tyler said overcrowding was occurring despite the addition of 716 new prison beds over the past year. The department reported that about 21 percent of the overall prison population and 30 percent of females inmates are doing time for drug crimes. The department said more than 28 hundred inmates imprisoned Monday were sentenced for drug crimes.