State prison officials blame a stunning increase in violence and lockdowns on mushrooming gang activity and budget cuts that reduced programs to keep inmates out of trouble.
Corrections chief Ari Zavaras outlined statistics in a briefing to state lawmakers.
Prisons were locked down 148 times in the 2007-08 fiscal year, an 80 percent increase with 66 more lockdowns than in the previous fiscal year, Zavaras said.
Assaults by inmates on other inmates rose 19.5 percent and assaults by inmates on staff went up 11 percent, he said.
The corrections chief said more high-security cells are needed to isolate problem offenders from the general population.
"In the last eight years, the gang population increased by 85 percent while our inmate population only increased by 42 percent," said prison spokeswoman Katherine Sanguinetti. More than 9,300 inmates of the total prison population of 23,000 are identified as gang members or affiliates, she said.
Many inmates bring their gang affiliations - and rivalries - with them. Others join gangs in prison for protection.
Sanguinetti said efforts are made to keep rival gang members away from each other, but with such high levels of gang affiliation, "they are going to run into each other more frequently."
More violence means more lockdowns, she said.