A toxic mix of severe overcrowding and frequent lockdowns was apparently at the heart of a melee involving as many as 18 inmates at the Oahu Community Correctional Center over the weekend.

Toni Schwartz, spokeswoman for the Hawaii Department of Public Safety, said the incident left three correctional officers with injuries that she said “were initially reported as minor.”

The incident occurred at about 7 p.m. Saturday in Module 17 at OCCC — an antiquated facility originally built in 1916 that has 19 modules on a 16-acre campus in Kalihi.

Cory Lum/Civil Beat

Schwartz declined to say what triggered the incident, citing a “pending investigation.”

Still, Schwartz said, “The situation was brought quickly under control, and inmates in the module were all placed on lockdown.”

Two OCCC employees, whom Civil Beat granted anonymity to protect them from reprisals, blamed the frequent use of lockdowns as the source of tension between inmates and correctional officers that ultimately led to the incident.

The Department of Public Safety has been opting to lock down the modules at OCCC to cover for absenteeism among correctional officers in recent years, instead of paying overtime expenses to bring in reinforcements and allow out-of-cell time for inmates.

The employees said the resentment has been building among inmates, who are locked down multiple times each week.

The stress of being locked down so often is compounded by the fact that overcrowding is endemic at OCCC — with up to four inmates being crammed into a cell.

According to Schwartz, 1,251 inmates were housed at OCCC on Saturday — in a space designed for 628 and capable of handling 954 operationally. Module 17, which can handle 48, housed 73 inmates at the time of the incident, she said.

Cory Lum/Civil Beat

One employee told Civil Beat that Saturday’s incident illustrates the grim reality inside OCCC.

“There’s so many things going on in this facility right now that I got to watch my back,” said the employee, who noted that two fights involving three gangs broke out recently in Module 19.

Schwartz declined to say whether the lockdowns played any part in Saturday’s incident.

Mateo Caballero, legal director of the American Civil Liberties Union of Hawaii, called for “a full and transparent investigation” of the incident.

“While we do not yet know what caused the violence, we do know that the widespread overcrowding and poor conditions in Hawaii jail and prisons — as detailed in our complaint to the U.S. Department of Justice — increases stress on inmates and guards, which in turn greatly increases the likelihood of violence at the facilities,” Caballero said.

Nolan Espinda, the director of public safety, praised OCCC officials for handling the situation “without major incident.”

“We never want to see these types of things happen to our employees, but everyone who works in a prison knows that dangerous situations can happen at any time,” Espinda said in a statement. “That’s why all staff go through extensive training so they are prepared to react immediately and stabilize the situation. They followed through with their training, and I commend them for a job well done.”

The Associated Press contributed to this report.