In early 2013, television reports – initially disbelieved – emerged that Bashar Al Assad’s Syrian government was using deadly chemical weapons against its own people.
It is a violation of international law that appears to have been repeated by the Sudanese Armed Forces a decade later as its civil war divided the country.
Robert Fairweather, a former chief of cabinet at the Organisation for the Prohibition of Chemical Weapon, said in all cases it was important the Chemical Weapons Convention, designed to deal with such allegations, was enforced by whatever means.
“There is a growing body of evidence that there may have been use of chlorine similar to Syria,” he said on Tuesday. “The barrel bombs look very similar to what was used in Syria. So, if we’re going to uphold the convention and uphold the norm, then let’s use that convention and ensure it’s done to the international standards.”
Crisis rewind
In Syria, stories from the BBC and CBS showing hospitals packed with victims drew international attention. A British Army security adviser to the BBC detailed the experience to his friend Hamish de Bretton-Gordon, a former commander of the British Army’s chemical, biological, radiological and nuclear regiment.
Initially, the veteran accompanied TV crews to the sites, saw the horrors of the chemical attacks and realised that he had to get verifiable samples to hold Al Assad’s regime to account.
“I was exasperated. Assad was using chemical weapons and I thought that we’ve got to do something about it,” Mr de Bretton-Gordon told The National.
The British and other governments alongside the OPCW said they needed hard evidence. Then, weeks later, in August 2013, about 1,500 Syrians were killed when the Syrian government used the nerve agent sarin in Ghouta.
The Collection Network
Desperate for advice on how to treat the casualties, the retired colonel was contacted by the Union of Syrian Medical Charities for help and set up the CBRN Task Force, whose initial role was to train medics. CBRN stands for chemical, biological, radiological and nuclear.
Given the ISIS terror campaign of beheading foreigners, the OPCW, intelligence agencies and others did not operate in the country.
“So we decided to set up our own collection network,” said Mr de Bretton-Gordon. They trained doctors and medics in how to collect evidence.
“The thing about collecting evidence is that it is only valuable if it has a complete chain behind it, and if there are any breaks in the chain, then it's not admissible,” he said.
They needed to reach evidential standards for the International Criminal Court if the regime was to face prosecution.
“It is laborious. Everything has to be documented, filmed, metadata and any samples have to be triple bagged," he said. "As you can imagine, Syria at the time was bandit country. I was there when some of the British aid workers were captured by ISIS and had their heads chopped off. So it was really dangerous.”
Despite that, and working with the renowned White Helmets civil defence, between 2014 and 2020 he went on several missions, bringing rucksacks full of protective equipment to wear when collecting samples, chemical detectors and “all the various bottles and bags you need”.
Beat the clock
When an attack was reported, the key was in getting very quickly to the site because sarin and chlorine, the chemicals Al Assad used, could quickly disappear.
“Chlorine is persistent for minutes, or possibly an hour in soil and longer in bricks, while sarin was persistent for days at most, but usually hours," Mr de Bretton-Gordon said. "If it's really hot and windy, it'll blow away in minutes, literally.”
But there was incriminating evidence to be found, including remnants of a chlorine barrel bomb with residue inside, alongside bricks that could retain the chemical for weeks if they were out of the sun.
The most effective evidence came from biomedical samples taken from victims of chlorine poisoning, including blood and hair samples from corpses.
“We collected as much evidence as we could then moved it across the Turkish border, handed it over to the authorities, and that went on 'til 2020.”
It is estimated that 50 per cent of the evidence of chemical war crimes that the UN and OPCW received came from the CBRN Task Force, some of which is being used today by the French government to indict Al Assad as a war criminal.
The first reports of chemical use in Sudan emerged in the media 10 months ago, and then an extensive intelligence dossier was published by The Washington Post this month.
Between 2013 and 2019, the Assad regime dropped chlorine barrel bombs up to 225 times on the population. Evidence now points to Sudan using similar chlorine devices on at least two occasions in September 2024, attacking opposition Rapid Support Forces-held Garri military base, then Al Jaili oil refinery a week later.
With witnesses and victims still alive there is still potential for operatives to enter the country to retrieve evidence of the attacks, as the CBRN Task Force did.
Battlefield to laboratory
But that comes with risk. There were some incredibly difficult times as well, said Mr de Bretton-Gordon, who wrote about his experiences in Syria in the book Chemical Warrior.
"I also remember very clearly there was a big chemical attack in Douma in April 2018 that killed at least 43 people,” he said.
Chlorine inside a bomb is liquid, which on detonation vaporises, but investigators can get residue if they find a canister and scrape the interior.
“You scrape it into a plastic sealable bottle, get that back to a certified lab, as you need to administer it correctly to get to the International Criminal Court standards. The whole thing worked very well.”
There are only a handful of laboratories around the world capable of handling the evidence and giving a reliable verdict on it.
Big four
The samples are normally divided by the OPCW and sent to several laboratories so that the results can be independently replicated, with the Chemical Weapons Convention requiring at least two designated laboratories for confidential analysis.
The Spiez Laboratory in Switzerland, established in 1928, is one of the world's leading CBRN laboratories.
The Finnish Institute for Verification of the Chemical Weapons Convention in Helsinki was also created specifically around chemical-weapons verification after the CWC process began.
Since 1916, the Defence Science and Technology Laboratory at Porton Down has been Britain's principal government laboratory for this kind of work, while the US has several OPCW-designated laboratories, including Lawrence Livermore National Laboratory in California.
Evidence tests
Samples can include soil, vegetation, bomb fragments, blood, urine, human tissue and clothing.
In a conflict such as Sudan, investigators may have to rely on trusted local contacts or ad hoc organisations such as the CBRN Task Force to collect material.
Scientists would look not only for the suspected agent but also for characteristic degradation products, precursors and other chemical signatures.
The laboratory findings would then be assessed alongside witness testimony, medical evidence, munition fragments and photographic evidence to determine whether it is consistent with deliberate chemical-weapons use.
“You have to get to the attack site and collect samples and find casualties or the people who have died, take biomedical samples off them then get it to the prescribed laboratory,” he said.
“But the key thing to all of this, it needs to be collected in the right manner, so that the chain of evidence is unbroken.”
