Reports of chemical-weapons attacks have hovered like a cloud over the bloody conflict in Syria for at least half a year, with both the Syrian opposition and the embattled regime of Syrian President Bashar Assad accusing the other of using poison gas in battle. After this weekend, international concern — and confusion — over the threat posed by chemical weapons in the Syrian civil war only deepened following a U.N. investigator’s claim that she had “strong, concrete suspicions” the Syrian rebels deployed sarin gas in a recent attack. The U.N. itself, though, has backed away from the allegation made by Carla del Ponte, and the Obama Administration says it’s “highly skeptical” of any suggestion that Assad’s opponents, as opposed to the regime, would be responsible.
With the actors and incidents shrouded in uncertainty, the focus then falls on the supposed floating menace itself: sarin gas, a lethal neurotoxin made illegal by the U.N.’s 1993 Chemical Weapons Convention, which allegedly exists in the Assad regime’s stockpiles. A German agricultural scientist in the employ of the Nazis invented the gas accidentally in 1938 when experimenting with new forms of pesticide, but it was never used during World War II. Just a small drop of the nerve agent, which turns quickly from liquid into gas, can be deadly; it is exponentially more dangerous than cyanide. My colleague Alexandra Sifferlin details its effects:
Within a few seconds of sarin-gas exposure, victims will start to experience eye pain, drooling, weakness, vomiting, diarrhea and irregular heart rates. Clothing from victims exposed to the gas will continue to release toxic vapors for 30 minutes, causing more people to come into contact with it. For those exposed to the liquid form of sarin, symptoms can occur anytime from a few minutes to 18 hours after consumption. If exposed to a large amount of sarin in either gas or liquid form, victims can experience more severe and painful symptoms such as convulsions, paralysis, loss of respiratory functions and even death.
Both the U.S. and the USSR maintained munitions equipped with sarin gas during the Cold War, though there’s no concrete evidence that these weapons were ever deployed. In March 1988, Iraqi bombers under orders from despot Saddam Hussein dropped a cocktail of sarin and mustard gas on the largely Kurdish city of Halabja, in northern Iraq, which was then occupied by Iranian troops battling Baghdad. The strike, which killed at least 5,000 people and injured tens of thousands, is now considered an act of genocide. A Human Rights Watch report from 1991 relayed eyewitness testimony from Halabja:
The city’s 70,000 or so inhabitants, many of whom were refugees from outlying areas, had already been pounded for two days from the surrounding mountain heights by conventional artillery, mortars and rockets. Many families had spent the night in their basements to escape the bombs. When the gas came, however, that was the worst place to be since the toxic chemicals, heavier than air, concentrated in low-lying areas. Between and 4,000 and 5,000 people, almost all civilians, died either at the time or shortly thereafter.
Hewa, a university student, survived by covering his face with a wet cloth and taking to the mountains around the city. He says that Iraqi warplanes followed, dropping more chemical bombs. “I got some gas in my eyes and had trouble breathing. You always wanted to vomit and when you did, the vomit was green.” He says he passed “hundreds” of dead bodies. Those around him died in a number of ways, suggesting a combination of toxic chemicals. Some “just dropped dead.” Others “died of laughing.” Others took a few minutes to die, first “burning and blistering” or “coughing up green vomit.” Journalists noted that the lips of many corpses had turned blue.
But sarin gas truly grabbed global attention when in 1995, far from the sectarian war zones of the Middle East, it was released into the Tokyo subway system by an obscure spiritualist cult known as the Aum Shinrikyo. Thirteen people died from exposure, while hundreds more were injured. Here’s an excerpt from TIME’s 1995 cover story on the attack:
“I saw several dozen people on the platform who had either collapsed or were on their knees unable to stand up,” recalls Nobuo Serizawa, a photographer. “One man was thrashing around on the floor like a fish out of water.” Those who could walk staggered up three flights of stairs to the clean, fresh air. Some vomited; others lay rigid … Three young women clung together like small birds in a nest, trembling and crying. Yet they made no sound; the gas had silenced their voices.
Within half an hour, similar scenes had unfolded at five other subway stops on three lines. Police arrived within minutes, administered some first aid and spirited thousands to hospitals, where doctors who suspected what had happened administered atropine, a sarin antidote. But for some it was too late. Kazumasa Takahashi, an assistant station manager at the Kasumigaseki stop, overstayed his shift to mop up the mystery liquid and dispose of the package that leaked it. He died a few hours later, and a colleague who helped him perished the next day.
Odorless and fast-acting, sarin’s seeming invisibility is what makes it so terrifying and perhaps underscores why President Obama was moved to describe the use of such chemical weapons as a “red line.” Still, the savagery of Syria’s two-year civil war, which has claimed more than 70,000 lives, ought to shock the outside world even without the specter of sarin gas. Just this weekend, activists reported the daylong sectarian slaughter of over 100 civilians, including women and children, in a suburb of the coastal city of Baniyas, allegedly at the hands of regime-affiliated militia.