WARREN – The Maine State Prison reached a benchmark this week that the old Thomaston prison never could have achieved.

The prison and its neighboring Bolduc Correctional Facility, known as the prison farm, earned national accreditation from the American Correctional Association.

Several other Maine prisons recently received similar status.

“It’s like bringing home the gold,” Warden Jeffrey Merrill said Wednesday, holding the large, gold-embossed certificate presented Sunday in Charlotte, N.C. “It’s such a milestone. It’s the first time in Maine history that [the Maine State Prison] is accredited. It would have been impossible at the old facility.”

The last milestone for Maine’s largest prison was in February 2002, when it closed its doors in Thomaston after 178 years and the new facility in Warren opened.

Between the Maine State Prison and the farm, there are 1,120 inmates and 450 employees.

On Sunday, Merrill, Capts. Ron Spearing and Millard Rackliffe, Sgt. Sean McGuire, and employees Dwight Fowles and Wendell Atkinson appeared before the American Correctional Association board of commissioners in Charlotte. They answered questions about discrepancies and submitted a corrective plan that was accepted, Merrill said. Accreditation was awarded Monday.

In January, the Maine Correctional Center in Windham received accreditation in Nashville, Tenn.

In May, Long Creek Youth Development Center in South Portland and Mountain View Youth Development Center in Charleston earned accreditation in Indianapolis.

The accreditation has more to do with prison policies, procedures and operations than how new a physical plant is. Three independent corrections inspectors conducted an in-depth review earlier this year of all Maine State Prison and Bolduc unit operations.

The inspection team probed prison security, food service, sanitation, medical and mental health services, prisoner programs and environmental conditions. Staff were drilled on duties and responsibilities, key and tool control and inventory, Merrill said, and they looked at record- and chemical-keeping practices, as well as the physical plant.

“It’s like coming through here with a fine-tooth comb,” Merrill said of the audit team.

To earn accreditation, there are some 500 standards to be met by adult maximum-security prisons. All mandatory standards must be met, and 90 percent of nonmandatory to be eligible for accreditation, Merrill said.

After a week of scrutiny, the Maine State Prison and the Bolduc unit both were found to have met 100 percent of the mandatory standards and ranked in the 98th percentile for nonmandatory.

Examples of nonmandatory gigs at the Bolduc unit are not having enough showerheads per inmate and being crowded. The unit is designed to house 150 inmates and there were 220 prisoners. Among the standards the Maine State Prison fell short on were not having a vocational education program in place.

All of the voc-ed programs are at the Bolduc unit, Merrill said. He said the state is working toward developing a program at the Maine State Prison, possibly in horticulture or culinary arts.

The Maine State Prison also was not strictly adhering to a nonmandatory policy that the senior security officer in charge make daily inspections of the special management unit to check on prisoners in disciplinary and administrative segregation. That officer must log in and out.

The value of accreditation is in making the facilities more responsible to public security and safer and more secure for prisoners and staff, Merrill said. The accreditation may also serve to curtail litigation, he said.

If the staff is keeping proper control of tools, for example, “assaults are limited,” he said.

The rating makes staff more accountable, more knowledgeable of its responsibilities and sets a standard that must be maintained. The prisons are reviewed every three years for reaccreditation.

“To get to this level, the staff has done very well, Merrill said. Accreditation is “certainly the move and the direction most states want to go. It puts you in the elite.”