State prison officials are asking lawmakers for $1.5 million to improve mental health services for prisoners at O'ahu Community Correctional Center in the wake of a federal investigation into the care provided to the mentally ill there.

A team of a half-dozen inspectors from the U.S. Department of Justice spent four days in October reviewing operations at OCCC, which is the state's largest prison, with more than 1,300 prisoners.

Justice officials have not yet released a formal report on their findings, but they pointed out a number of problems during a briefing after the inspection, said Frank Lopez, acting director of the state Department of Public Safety.

Based on that briefing, prison officials are seeking money from the state Legislature to hire more treatment staff and a dozen new corrections officers to provide security for stepped-up treatment programs for inmates, said OCCC Warden Nolan Espinda.

Lopez said the prison has mental health services, but the inspection team made it clear the services "have to be greatly improved." He told state senators last week that the department plans to improve mental health services statewide, starting with OCCC.

The courts traditionally would transfer inmates with acute mental illnesses to the Hawai'i State Hospital's secure treatment facility, Lopez said. However, that facility has been so full that the prisoners must spend longer and longer periods at the prison waiting for space to open at the hospital.

Because of that time lag, "the federal government has come in and said, 'You really need to provide these services at correctional facilities,' " Lopez said.

The Justice Department notified Gov. Linda Lingle in a letter last June that it was investigating the mental health services provided to inmates and detainees, and the October inspection was part of that inquiry.

The investigation is a serious concern because if the state mental health services are deemed to be inadequate under federal law, that could trigger a federal lawsuit under the Civil Rights of Institutionalized Persons Act.

OCCC was under federal court supervision from 1986 to 1999, under the terms of a federal consent decree that forced the state to limit the population of the facility and make a variety of improvements there.

Espinda estimated about a third of the inmates at the prison have varying degrees of mental health problems.

Inmates with acute mental illnesses are housed in module 4, which holds up to 35 inmates, and module 3 is set aside for "step-down inmates" who are stabilized and are preparing to rejoin the general population.

Women inmates with mental health problems are housed in module 8, which has 24 beds, Espinda said.

Espinda said most of the federal inspectors' recommendations involved improving services in those three modules. The inspectors also wanted better screening for inmates as they enter or leave the prison, he said.

Reach Kevin Dayton at kdayton@honoluluadvertiser.com.