When a Syrian prison guard threw him into a dimly lit room, inmate Abdo was surprised to find he was standing ankle-deep in what appeared to be salt.

On this day in the winter of 2017, the frightened young man had been locked up in war-torn Syria’s largest and most notorious prison, Sednaya, for two years.

Having largely dispensed with salt in his meager prison ration throughout, he happily raised a handful of the coarse white crystals to his mouth.

Moments later came the second, grisly surprise: as a barefoot Abdo strode cautiously across the room, he stumbled over a corpse, emaciated and half-buried in salt.

Abdo soon found two more bodies, partially dehydrated from the mineral.

He had been thrown into what Syrian inmates call “salt chambers” — primitive morgues designed to preserve bodies in the absence of refrigerated morgues.

The bodies were treated in a manner already familiar to the embalmers of ancient Egypt, to keep up with the mass killings in prisons under President Bashar al-Assad’s regime.

The salt chambers will be detailed for the first time in an upcoming report by the Association of Detainees and the Missing in Sednaya Prison (ADMSP).

In additional research and interviews with former inmates, AFP found that at least two such salt rooms were created in Sednaya.

Abdo, a Homs man who is now 30 and lives in eastern Lebanon, asked that his real name not be released for fear of reprisals against him and his family.

Speaking from his small rented apartment in an unfinished building, he recounted the day he was thrown into the salt room that served as his holding cell before a court-martial hearing.

“My first thought was: May God have no mercy on them!” he said. “They have all that salt, but don’t put anything in our food!

“Then I stepped on something cold. It was someone’s leg.”

Up to 100,000 people have died in the Syrian regime’s prisons since 2011, a fifth of the war’s total death toll, according to the UK-based monitoring group the Syrian Observatory for Human Rights.

Abdo, lucky enough to have survived, described the salt room on the first floor of the red building as a rectangle about six by eight meters (20 by 26 ft) with a rudimentary toilet in one corner.

“I thought that was my fate: I would be executed and killed,” he said, recalling curling up in a corner, crying and reciting verses from the Koran.

The guard eventually returned to escort him to court and Abdo survived to tell the story.

On his way out of the room he had noticed a pile of body bags by the door.

Like tens of thousands of others, he had been arrested on blanket terror charges. He was released in 2020 but says the experience marked him for life.

“It was the hardest thing I’ve ever experienced,” he said. “My heart died in Sednaya. If someone were to announce my brother’s death now, I wouldn’t feel anything.”

Around 30,000 people are believed to have been held in Sednaya alone since the conflict began. Only 6,000 were released.

Most of the others are officially missing because death certificates rarely reach families unless relatives pay an exorbitant bribe, which has become a huge uproar.

AFP interviewed another former inmate, Moatassem Abdel Sater, who recounted a similar experience in 2014 in another ground-floor cell measuring about four by five meters with no toilet.

Speaking at his new home in the Turkish city of Reyhanli, the 42-year-old said he was standing on a thick layer of salt used to de-ice roads in winter.

“I looked to the right and there were four or five bodies,” he said.

“They looked a bit like me,” Moatassem said, describing how their skeletal limbs and scabies-covered skin matched his own gaunt body. “They looked like they had been mummified.”

He said he still wonders why he was taken to the makeshift morgue on the day of his release, May 27, 2014, but suspected that “maybe it was just to scare us.”

The ADMSP, after extensive research into the notorious prison, dates the opening of the first salt room to 2013, one of the deadliest years of the conflict.

“We found that there were at least two salt rooms that were used for the bodies of those who died from torture, disease or starvation,” said the group’s co-founder Diab Serriya during an interview in the Turkish city of Gaziantep.

It was not clear if both rooms existed at the same time or if they are still in use today.

Serriya explained that a dead inmate usually stays in the cell with the inmates for two to five days before being taken to a salt room.

The bodies stayed there until they were enough for a truckload.

The next stop was a military hospital where death certificates were issued before mass burials, often listing a “heart attack” as the cause of death.

The salt rooms were designed to “conserve the bodies, curb the stench … and protect the guards and prison staff from bacteria and infection,” Serriya explained.

US-based anatomy professor Joy Balta, who has published numerous papers on human body preservation techniques, explained how salt could be used as a simple and inexpensive alternative to cold storage.

“Salt has the ability to dehydrate any living tissue… and therefore can be used to significantly slow the decomposition process,” he told AFP.

A body can stay in the salt longer than it could in a purpose-built cold chamber without decomposing, “although that will change the surface anatomy,” said Balta, who founded the Anatomy Learning Institute at Point Loma Nazarene University in San Diego.

The ancient Egyptians are known to have used the mummification process, which involved immersing the body in a salt solution called natron.

The tons of rock salt used at Sednaya are believed to have come from Sabkhat al-Jabul, Syria’s largest salt pan, in Aleppo province.

ADMSP’s report is the most thorough study yet of the structure of Sednaya, which has been producing death at a terrifying rate for years.

It contains detailed schematics of the facility and shows how duties were divided between different army units and overseers.

“The regime wants Sednaya to be a black hole, nobody is allowed to know about it,” Serriya said. “Our report denies them that.”

Fighting in Syria’s brutal war has died down in the past three years, but Assad and the prison that has become a monument to his bloody rule still exist.

New layers of the horrors of war are still being uncovered as survivors abroad tell their stories, and investigations of regime crimes by foreign courts fuel a drive for accountability.

“Should there ever be a political transition in Syria,” Serriya said, “we want Sednaya to be turned into a museum like Auschwitz.”

The prisoners remember that their greatest torment, along with torture and disease, was hunger.

Moatassem said his weight had more than halved, from 98 kilograms when he was incarcerated in 2011 to 42 kilograms when he was released.

The ex-cons also find sickening irony in the fact that the salt they craved so badly was an integral part of the horrific death machine that decimated them.

The wheat, rice and potatoes they were sometimes fed were always cooked without salt or sodium chloride, the lack of which can have serious health effects on the human body.

Low blood sodium levels can cause nausea, dizziness, and muscle spasms and, if they persist, coma and death.

Prisoners used to soak olive pits in their water to salt it and even spent hours sifting through detergent to seek out tiny crystals, which they treated like a delicacy.

Former inmate Qais Murad recounted how he was called out of his cell to see his parents on a summer’s day in 2013, but was pushed into a room on the way to the visiting area.

Inside, he stepped on something like sand on the floor. He knelt against the wall with his head bowed and caught a glimpse of the guards dumping about 10 bodies behind them.

When a cellmate returned from a visit later that day, his socks and pockets stuffed with salt, Murad understood what the substance was about.

“From that day on, we always wore socks and pants with pockets for visits in case we found salt,” Murad told AFP, also in Gaziantep.

He recalled how excited cellmates ate boiled potatoes with the first pinch of salt that day in years, unaware of their origins.

“All we were interested in was the salt,” Murad said. “Salt was a treasure.”