A prison sergeant who hit the wrong button probably is to blame for abruptly opening 20 cell doors in a Mississippi prison disciplinary unit last month, releasing about three dozen Hawai'i inmates and triggering a violent disturbance, prison officials said yesterday.

Two prisoners in the Tallahatchie County Correctional Facility unit were hospitalized after other inmates attacked them when the cell doors opened at 2:48 a.m. on July 17. One of the inmates, Ronnie Lonoaea, remains in a Mississippi rehabilitative hospital with head injuries.

After the doors opened, two inmates immediately began fighting and eight others rushed into a single cell to attack Lonoaea, prison officials have said.

Other inmates used a telephone cord to tie shut the door leading into the unit in a makeshift barricade to keep prison officials out, according to a report on the incident.

The Tallahatchie prison staff dropped tear gas grenades from the roof into the Special Housing Incentive Program, or SHIP unit, and regained control of the unit about 90 minutes after the cell doors opened, according to the report.

The SHIP unit incident is the first significant disturbance at the privately run Tallahatchie prison since Hawai'i inmates began arriving there last year. The prison now holds about 850 convicts from Hawai'i; they are most of the population of the 1,100-capacity prison.

The SHIP unit is used to house the most unruly Hawai'i inmates as well as suspected prison-gang members.

Two dozen prisoners from the SHIP unit are being locked down for 23 hours a day as punishment for the disturbance. Five other inmates may face felony assault charges in connection with the attack on Lonoaea, said Shari Kimoto, Mainland branch administrator for the Hawai'i Department of Public Safety.

Prison owner Corrections Corp. of America hired two outside security companies to investigate why the cell doors opened, but investigators were unable to find any mechanical problem that could account for the doors suddenly opening, Kimoto said.

However, the report also notes that after the doors first opened, prison staff tried to close the cell doors but were unable to do so. After the disturbance was put down, corrections officers were still unable to close three of the cell doors in the unit, Kimoto said.

In the company's report to Hawai'i officials on the disturbance, CCA said it will retrain its corrections officers on the use of the group release button and will install fail-safe buttons in every prison housing unit to prevent any similar problems.

With the new system, two corrections officers will have to simultaneously hold down buttons at opposite ends of the control panels to open all cell doors in a living unit at once, Kimoto said.

Kimoto said a security team from Hawai'i will travel to Mississippi early next month to inspect the prison, and will gather more information about the disturbance then.

Lonoaea, 32, is serving time for burglary and has an extensive history of prison assaults, including two attacks on prison staff at Tallahatchie, according to Hawai'i prison officials.

Kimoto said Lonoaea, who suffered severe head injuries in the attack, also has been abusive toward hospital and corrections staff during his stay at two Mississippi hospitals.

Allen Lonoaea, Ronnie's older brother, said Ronnie should be kept in a hospital where he can be treated for mental illness. Allen Lonoaea said he is concerned his brother would be in danger at the Tallahatchie prison.

Kimoto said top Hawai'i prison officials will discuss where to place Lonoaea when he is released from the hospital.

The state will pay about $36 million this year to house about 1,850 inmates in private prisons on the Mainland because there is no room for them in Hawai'i prisons.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.