With the shortlist of Oahu Community Correctional Center replacement sites now in hand, a draft environmental impact statement could be in the works before the end of the year. And, if the state holds pace, construction of a sorely needed new jail could begin in 2020 and wrap up three years later.

So, six years from now the outdated and overcrowded 40-year-old OCCC — which houses more than 1,300 inmates in a facility originally designed for 628, but modified over the years to house about 950 — could be gone from its site in urban Honolulu. That would be a relief for just about everyone from inmates to Gov. David Ige, who initiated the current effort to expand jail capacity and improve deplorable conditions.

Two years ago, Ige released $5 million, set aside but unspent under the Abercrombie administration, which has enabled the state to solicit proposals to replace OCCC. Last week, legislators were told that so far the state has spent about $1.2 million of that funding on a study that narrowed the top site prospects to four options: the current 16-acre OCCC lot in Dillingham; the Halawa Correctional Facility site and the state Department of Agriculture’s Animal Quarantine Facility site in Halawa Valley; and “Lot 17” in Mililani Technology Park.

Lawmakers did the right thing by seizing upon the site apparent (Halawa) and moving to push the process along by earmarking $66 million in the Senate draft of the state budget — $60 million to design the new jail, and $6 million for environmental studies and planning for additional prison bed space at Halawa.

While Halawa ranks highest among the proposed sites, the state will continue to evaluate each in an environmental impact statement before making a final selection. But the longer the debate continues over how to replace OCCC and upgrade other correctional facilities, the higher the taxpayer bill for conditions that are less than humane.

As Ted Sakai, former director of the state Department of Public Safety, said last month: “We are spending tens of millions of dollars a year simply to keep our facilities running safely. Eventually, all the duct tape in Hawaii won’t be enough.”

Sakai said chronic overcrowding often means this: three inmates spending up to 16 hours a day together in a cell — 8 feet by 10 feet — with a double bunk, a toilet/sink combo and a small writing desk. The inmate bumped from the bunk gets a mattress, and sleeps on the cell’s floor.

What’s more, OCCC’s outdated design consists of 19 modules, each of which has to be guarded by a separate team of officers. By contrast, the medium-security wing at Halawa, which is the state’s newest, has just four modules. Officials have griped that it takes about 100 more correctional officers at OCCC to guard the same number of inmates as at Halawa, which opened in 1987. Such inefficiency adds up to an enormous waste in funding in a state that’s hard-pressed to provide schoolchildren with adequately cooled classrooms and tend to a daunting homelessness problem, among other issues.

The envisioned facility would include a new jail to house pretrial and short-term inmates to replace OCCC, and a new prison that would allow the state to bring back convicts who are now serving their sentences at a privately operated prison in Arizona due to overcrowding in Hawaii. The preliminary cost estimates for the new jail range from $433 million for a low-rise facility to $673 million for a high-rise option on the Halawa prison property.

OCCC currently costs $67.3 million a year to operate. According to consultants hired to plan and design the new facility, the state could save an estimated $4.8 million a year in reduced staffing costs with a modern low-rise jail. The high-rise option could save about $3.8 million a year. State lawmakers and others weighing in on OCCC’s future must maintain a purpose-driven pace that will open the doors to a cost-efficient facility — complete with adequate bed capacity and other improved inmate- related conditions — within the current target of six years.