A Massachusetts state prison is expanding the graveyard where it buries inmates who die in custody, one consequence of the state's huge increase in aging prisoners. And as more inmates age and die behind bars, the cost of their care is skyrocketing, fueling new efforts to release prisoners who are too old or sick to pose a threat.

With 17 percent of its inmates now older than 55, Massachusetts has one of the highest rates of aging prisoners in the nation. And nationally the number of inmates older than 55 years old in state prisons has quadrupled since the '90s, due largely to longer prison sentences for violent crimes and an uptick in people older than 55 being sent to prison, according to the latest Justice Department report. When some of these inmates die in prison and their bodies go unclaimed by family, they're buried in a prison cemetery, under crosses made out of white plastic plumbing pipe. About three or four prisoners' bodies go unclaimed by family each year.

"It's very humble. It's nothing much," said Kerry Keefe, the director of treatment at this state prison who's also in charge of burying prisoners whose bodies go unclaimed by family — about three or four a year.

"This isn't a bad place to spend eternity, but I think you'd want someone to cry for you," he added.

A local funeral home charges the prison about $1,000 per burial, but a new law creating a system for medical parole in Massachusetts could spare the state that small cost and millions of dollars more spent caring for the oldest and sickest of inmates.

All but four states in the U.S. have such a provision, also known as compassionate release, but it's rarely used. In Massachusetts, the new parole is an option only for prisoners who can prove they are physically or cognitively incapacitated.

But even Keefe, who expressed some sympathy for the inmates he's helped bury, is skeptical of releasing such prisoners.

"I get it kind of saves money," Keefe said. "It's fairly obvious the person can't do any kind of serious destructive behavior, but you got to pay attention and temper it with the demands of justice."

Also pushing back is Charlie Baker, the state's Republican governor. Baker's staff pressed state lawmakers last spring to exclude first-degree murderers and some sex-offenders from eligibility for medical parole.

In a medium-security state prison in Shirley, Mass., 38 beds in a locked unit are set aside for inmates needing assistance with basic daily tasks.

"We have individuals who are full care patients that may be post-stroke or in complete quadriplegia that just require our full care — with everything — dressing, changing, and diapering. And then we have patients who suffered from dementia and they are just confused," said social worker Elizabeth Louder who oversees what looks like a nursing home behind bars.

Massachusetts doesn't track the cost of caring for these inmates, but its prison hospital spends more than $283,000 a year to care for a single, sick inmate, four times the cost of housing an inmate in its maximum security prison.

George McGrath, age 70, was convicted in 1969 of first degree murder for his role in the death of two men in a drug store robbery. He is incarcerated at the "Assisted Daily Living" unit at MCI-Norfolk. He is seeking medical parole, claiming he is old, sick, and not a safety risk. McGrath said prison is a "young man's game...obviously I'm not a young man anymore."

Studies by Pew Charitable Trusts found that older prisoners with chronic illnesses cost at least two times more than other inmates. When prisoners need specialty care in off-site hospitals, officers go along to guard them, sending costs even higher.

Joseph Labriola, a 71-year-old inmate in the Shirley prison, said he was guarded around the clock when pneumonia landed him in a hospital off prison grounds.

"Two guards. You have one sitting at the door with a gun and the other one sits right next to your bed, and your leg is chained to the bed," he said.

Labriola has been in prison 45 years, serving life without parole for murdering an alleged drug dealer – a crime he says he didn't do. His health problems include chronic lung disease that he blames on exposure to Agent Orange when he was a soldier in Vietnam. He now gets around in a wheelchair, pushed by a younger inmate. More than anything, he doesn't want to die behind bars.

"Dying in prison has a special aura to it. You're not surrounded by people who love you, there's nobody's going to hold your hand on the way out the door," he said.

Peter Koutoujian, a county sheriff in Massachusetts, is adamant that medical parole is the best a solution for the worst-off inmates.

"If you're terminally ill or you're medically incapacitated, you shouldn't have to be in a jail number one and you don't need to be in a jail, number two," he said.

One big question surrounding the new policy in Massachusetts is where paroled inmates would go and who'd pay for their care. Backers of the new policy say federally-funded Medicaid or Medicare would cover costs.

Patricia Jehlen, the state senator who helped write the medical parole law, said some local hospice organizations are willing to take in prisoners.

"It's going to allow people to die in a little more humane circumstances," she said. "The growing number of elderly and incapacitated prisoners who are extremely expensive and hard to care for could be cared for in a much less expensive environment."

But Massachusetts is an unforgiving landscape for convicts looking for parole, partly due to the Willie Horton effect. Horton was a convicted murderer who raped a woman in the 1980s while furloughed from prison. Political ads featuring Horton in the 1988 presidential campaign helped sink former Massachusetts Gov. Michael Dukakis' bid for the White House.

Since 2000, 769 inmates have requested commutations — or a reduction of their sentence — from the state Parole Board, but only one request has been approved by a sitting governor, state records show.

Nationally, compassionate release programs have produced scant results. Few states are mandated to track the number of prisoners released under such programs and only a handful of inmates have won release in the states that keep any data, according to  a report released in June by Families Against Mandatory Minimums, a nonprofit in Washington, D.C. A 2013 Justice Department report called the compassionate release program for federal prisoners "poorly managed and implemented inconsistently" and likely caused some eligible inmates to be overlook and left others to die before their requests were determined.

And back in Massachusetts, the state just rejected the first petition for medical parole from an inmate with pancreatic cancer, saying his release would still pose a public safety risk.

This story aired on National Public Radio's All Things Considered. WGBH news aired an earlier version.