The Airway Heights Corrections Center remained locked down Monday following a fight involving 16 inmates on Sunday afternoon.
Injuries from the melee were mostly minor. However, one inmate required hospital treatment. That inmate was returned to the medium-security prison from the hospital about three hours after the fight and placed in administrative segregation.
Three staff members suffered minor injuries, mainly bruised knees, said James Key, associate superintendent.
The staff members were not assaulted by inmates, officials said.
Key said it was too early to know what caused the fight. The fight occurred about 4 p.m. in a walkway between two medium-security living units.
Those who were involved in the fight were moved to administrative segregation as part of the investigation.
Any discipline will be handled within the prison system, Key said.
Local law enforcement was not involved in the investigation, he said.
The medium security facility houses approximately 1,570 offenders in six living units. The lockdown was expected to continue during the investigation. Inmates are held in their cells during lockdown.
An adjacent minimum security unit houses 600 offenders and was not placed on lockdown.