Did Sudan use chemical weapons in Darfur last year?

After nearly 14 years of war, the most recent violence to ravage the western Sudanese region of Darfur came in the form of a large-scale military offensive last year in the area of Jebel Marra, a 5,000-square-kilometer volcanic massif that’s home to about 1,500 villages. Ostensibly aimed at members of an armed opposition group, the nine-month operation mostly victimized civilians, and the government in Khartoum has been very successful in hiding these violations. Journalists, human rights investigators, humanitarian actors, and even international peacekeepers have been denied all meaningful access to the area.

Yet starting last February, a month after the offensive began, Amnesty International conducted a remote investigation and found overwhelming evidence of war crimes and possibly crimes against humanity—of indiscriminate bombings, the unlawful killing of civilians, the abduction and rape of women, the looting and destruction of entire villages, and the forced displacement of an estimated quarter-million civilians. The probe also unearthed credible evidence that strongly suggests Sudanese government forces used chemical weapons during their campaign.

Since we published our report in September, Amnesty has gone on to advocate that members of the Chemical Weapons Convention take action regarding the chemical-warfare allegations. This is, after all, why the treaty exists. But while a number of nations have expressed interest in the findings, none has taken formal steps to press for more information. This is mainly because the existing evidence has been gathered from afar and, as a result, no physical samples could be collected, which is admittedly not ideal. But given how the Sudanese government has blocked access to the affected area, the lack of an on-site investigation should be no excuse for doing nothing. Amnesty International’s detailed information was credible enough that two separate experts, independently of each other, have concluded that chemical weapons were likely used in Jebel Marra. Inaction in the face of these findings sends a terrible signal to the government of Sudan and threatens the standing of the chemical convention itself.

Parsing the evidence. Amnesty International interviewed, by phone, 57 residents of Jebel Marra—47 civilians and 10 members of the armed opposition group, the Abdul Wahid faction of the Sudan Liberation Army—who provided firsthand accounts of exposure to alleged chemical-weapons agents. Amnesty also interviewed several caregivers who, in total, looked after several hundred survivors of the alleged chemical attacks. These caregivers described signs they observed on the bodies of their patients and, often, what they observed to be the proximate cause of death. Both the survivors and the caregivers also provided substantial photographic evidence of visible injuries.

According to these witnesses, the suspected chemical-weapons agents were delivered by bombs and rockets, which released a noxious smoke or gas that often changed color after it was discharged. Survivors and caregivers described a wide variety of ailments that victims experienced during the hours and days after exposure. These included: severe, often bloody, vomiting and diarrhea; severe dermatological problems such as blisters, rashes, and skin falling off; ocular problems such as changes to eye color, bulging eyes, constant discharge of liquid, and a reduction or total loss in vision; and severe coughing and difficulty breathing, which often resulted in suffocation. Extraordinarily bloody miscarriages were also commonly reported, and numerous victims were said to be rendered unconscious by exposure to agents. Witnesses mentioned dramatic changes to the smell of breath as well, and to the color and smell of urine and stool, and many victims experienced involuntary muscle contractions and seizures, which were often fatal.

Two chemical-weapons experts, Keith Ward of George Mason University and Jennifer Knaack of Mercer University, separately evaluated this evidence for Amnesty International. Their analysis had certain obvious constraints brought on by the remote nature of the investigation, which did not permit a direct examination of victims by medical professionals with access to modern medical technology. They had no soil samples, weapons remnants samples, or physiological specimens like blood or urine, which would be required to obtain definitive proof of exposure to a chemical agent. Instead they based their conclusions on what was available from detailed interviews with survivors and caregivers and a small sample of photographs—often taken days or weeks after the attack—of the visible wounds, which frequently had been left untreated.

After analyzing environmental descriptions of the attacks, along with photographic evidence and reported symptoms and clinical signs, and after extensive discussions with medical doctors familiar with the effects of chemical and biological warfare agents, both experts determined that the wounds of these victims were not due simply to the effects of conventional explosive or incendiary weapons of war, and that many victims suffered injuries that can only be explained by exposure to chemical agents delivered by weapons used in the attacks.

Some of the most telling evidence came from the testimony of the many victims who had escaped bomb, rocket, and gun attacks without any injuries, only to develop wounds hours or days later. These wounds often developed on areas that were covered by clothing during the attacks, indicating that chemical exposure occurred and that toxicity could have come from chemicals that entered the bloodstream. Conventional weapon injuries will not be present on clothed regions of the body without destroying the clothing, which was not described in any testimony.

The experts also analyzed specific details in photographs, as well as descriptions of signs and symptoms, to determine which chemicals, or classes of chemicals, were used in the attacks. The absence of physical evidence made firm conclusions impossible, but both experts independently came to the same conclusion: that clinical signs and symptoms of many of the victims were most consistent with exposure to a class of chemical-warfare agents called vesicants or blister agents, which include lewisite, sulfur mustard, nitrogen mustard, and phosgene oxime.

It is worth noting as well that both experts said many of the observations reported were not those normally associated with exposure to vesicants. So it is possible that victims of these attacks had been exposed to other chemicals instead of, or in addition to, blister agents. In addition to vesicants, for example, which might account for long-term effects like blistering that doesn’t heal and persistent coughs, victims could have also encountered vomiting agents, which could account for immediate symptoms such as nausea and vomiting. The experts considered a variety of other common chemical-warfare agents—as well as things like white phosphorus, tear gas, and biological toxins—but could not conclude that any of them were used.

Demanding action. In response to these findings, Amnesty International has called on members of the Chemical Weapons Convention to press Sudan for answers. Specifically, we have asked members of the convention to formally request the Executive Council of the Organisation for the Prohibition of Chemical Weapons, the body that polices the chemical treaty, to obtain “clarification” from Khartoum about the allegations. Such a request is a recommended (though not mandatory) first step, under Article IX of the convention, that allows any nations who have signed the treaty to request an on-site “challenge inspection” into alleged violations by any other party nation—a request that can only be denied if three-quarters of the 40-member Executive Council votes to overrule it.

While the government of Sudan, a signatory to the convention, has denied the allegations and dismissed Amnesty’s report, responses by other members has been relatively tepid. The United States and France have publicly stated they are taking the report seriously and are examining the evidence; other countries have made similar statements in private. Elected officials from several countries have taken a more forceful stance, including 32 US lawmakers who wrote to Secretary of State John Kerry calling for Washington to request an investigation. Still, no country has yet made the formal request.

From a historical perspective, the reluctance to initiate an investigation is not surprising. The standard for triggering a challenge inspection, although technically left up to the discretion of individual treaty members, appears to be set quite high. Since the convention came into force in 1997, there has not once been a call for such an inspection. For example, in response to the recent allegations of chemical-weapons use in Syria, member states did not trigger the investigative mechanism; rather, they launched a Joint Investigative Mechanism between the United Nations and the Organisation for the Prohibition of Chemical Weapons—an act that required a Security Council resolution.

Based on discussions between Amnesty International and treaty members who claim to find the report credible and are seriously examining the possibility of asking for “clarification,” the reason for deciding not to take any formal steps under Article IX is the absence of physical evidence. Yet while physical evidence is undeniably necessary to conclusively prove the use of chemical weapons, its absence is no excuse for the lack of an investigation, especially considering the reality of the situation unfolding in Sudan and the credibility of the evidence already documented.

For example, the international peacekeeping mission in Darfur is jointly mandated by the UN Security Council and the African Union Peace and Security Council to use force to protect civilians and to report on violations of human rights. The mission has a status-of-forces military agreement with Khartoum entitling it to full and unrestricted movement throughout Darfur, including the areas where the alleged chemical-weapons attacks occurred. Yet the mission has been unable to fulfill its mandate to protect civilians in Jebel Marra or report on human rights violations that have taken place in the area, including the alleged use of chemical weapons, because the government has denied all access. Local residents who attempt to enter or leave certain parts of Jebel Marra face grave, often fatal, risks, as do those who attempt to report information to investigators. By refusing to trigger the Article IX investigative mechanism, the nations of the world are essentially rewarding the government of Sudan for creating an environment that makes gathering physical evidence nearly impossible.

There already exists substantial, credible evidence suggesting widespread use of chemical weapons by Sudanese government forces during its military offensive in Jebel Marra. This evidence should, at the very least, prompt other nations to request that Sudan provide formal clarification. If it does not, the international community not only encourages the government of Sudan to violate the chemical convention with impunity but also calls into question the credibility of the treaty itself.