The U.S.'s 64-Square-Foot "Torture Chambers"

He has not had human contact or a good night's sleep in nearly three decades. Every single day, he wakes to the sound of metal doors clanging open and a pair of disembodied hands pushing a tray of food through a slot into his 64-square-foot cell.

For the next 23 hours, he will stare at the same four walls. If he is lucky, he'll be escorted, shackled at his ankles and wrists, into a "yard" - an enclosure only slightly larger than his cell - for an hour of solitary exercise.

This is how Russell "Maroon" Shoatz, a prisoner in the restricted housing unit at the State Correctional Institute (SCI) Frackville in northern Pennsylvania, has spent the past 22 consecutive years.

On Thursday, Shoatz's lawyers submitted a communication to Juan E. Mendez, the United Nations' special rapporteur on torture and other cruel, inhuman and degrading treatment or punishment, urging him to inquire into why a "father, grandfather and great grandfather" is being held in extreme isolation despite having a near-perfect disciplinary record for over 20 years.

The appeal comes on the heels of a surge in public debate on the practice of solitary confinement in the United States, where on any given day an estimated 81,000 men, women and children are held in some form of "restricted housing" unit, according to Federal Bureau of Justice statistics.

Authorities in each state have a myriad of euphemisms for the practice: administrative segregation, secure housing units (SHUs), "supermax" facilities, protective custody. Whatever the language, critics say the basic conditions remain the same: extreme isolation and sensory deprivation for years at a time.

According to a 2012 report by Human Rights Watch (HRW), the restrictions imposed in "maximum security" facilities often "exceed the fathomable. In Pennsylvania's most restrictive units, for example, prisoners have all the usual supermax deprivations plus some that seem gratuitously cruel: they are not permitted to have photographs of family members or newspapers and magazines."

Mendez has already affirmed that holding a human being in isolation for a period exceeding 15 days constitutes a violation of the U.N. Convention Against Torture (CAT).

Back in 2011, his office called for a complete global ban on the use of solitary confinement "except in the most extreme circumstances and for as short a time as possible", citing numerous studies - some dating back decades, others as recent as Amnesty International's 2012 report 'The Edge of Endurance' - that have documented the long-lasting psychological impacts resulting from even a few days of social separation.

This past August, a hunger strike involving over 30,000 prisoners protesting conditions in restricted housing units at the Pelican Bay State Prison in California prompted the rapporteur to make an urgent appeal to the U.S. government to "eliminate the use of prolonged or indefinite solitary confinement under all circumstances", stressing that the average U.S. prisoners banished to the hole typically stays there roughly 7.5 years - "far beyond what is acceptable under international human rights law."

Harold Engel, an attorney with over 43 years of experience and a retired partner of the global corporate law firm Reed Smith, said he co-signed the appeal Thursday in the hopes that an investigation undertaken by the office of the special rapporteur, housed at the Office of the High Commissioner for Human Rights (OHCHR) in Geneva, will bring an end to indefinite isolation.

"I first became involved in this case because my daughter told me about Shoatz's situation and I found it abhorrent," Engel told IPS.

"As I learned more I realised there wasn't any clear law on the question of whether keeping someone in solitary confinement under conditions that Shoatz has been kept in violates the eighth amendment of the U.S. constitution [prohibiting the government from imposing cruel and unusual punishment] - which, in my opinion, it does."

Speaking to IPS under condition of anonymity, an inmate who spent several years in solitary confinement in a Pennsylvania prison before being released back into the general population said his life was measured out in a series of arbitrary numbers: he was permitted one hour of exercise on five days out of the week; he was allowed three meals a day but zero contact visits with his family. His cell contained a single cot and one steel sink. Showers were taken thrice weekly, overseen by guards.

"Getting through each day felt like hewing a single stone from a mountain of despair," he said.

Bret Grote, an activist who has worked for over six years with the Human Rights Coalition (HRC) - an advocacy group comprised predominantly of prisoners' families, ex-prisoners and their supporters - says he and others have documented "hundreds upon hundreds of instances of torture and other cruel, inhuman and degrading treatment inside the solitary confinement units of Pennsylvania Department of Corrections (PA DOC)."

"The approximately 2,500 prisoners warehoused in solitary by the PA DOC are held in units where physical abuse, psychological deterioration, retaliation for exercising constitutionally-protected rights, food deprivation, extreme social isolation, severely reduced environmental stimulation, theft and destruction of property, obstruction of access to the courts, and racist abuse are normative features," Grote told IPS.

As Shoatz's lawyers await an official response from the U.N. rapporteur, they are holding out hope that a full investigation into his case could also bring some respite for the tens of thousands of others enduring such conditions.