A riot broke out at salinas valley state prison tuesday morning. terry thorton, the spokeswoman for California department of corrections and rehabilitation said at least 18-people were seriously injured in the fight that involved over 150-people. No prison staff were hurt in the incident, which occurred in the exercise yard of a maximum security unit. among the injured prisoners, 1-person was airlifted to an out-of-county hospital, while 7 were taken by ambulance to local hospitals, and 10 inmates were treated at the prison. Thorton said numerous jail-made weapons were used in the fight. Prison staff were able to quell the fight using non-lethal ammunition and a mace-like foam- spray. Investigators are still trying to determine what sparked the riot.