Syria Chemical materials and gas masks 370.
(photo credit: REUTERS)
AMSTERDAM - As UN weapons inspectors came under fire in
Syria on Monday, the evidence of an apparent large-scale chemical weapons attack
they are seeking is already fading from the scene.
The longer it takes
the 20 experts to get to the spot where rockets carrying nerve agents are said
to have killed hundreds of people on August 21, the harder it will be for the
mission led by Swedish scientist Ake Sellstrom to find meaningful remnants of
With Western powers considering military strikes
against the government of Syrian President Bashar Assad if they conclude he
used gas-laden rockets in an escalation of the country's two-and-half-year civil
war, reliable evidence will be key to their deliberations.
chemicals on munitions fragments, buildings and impact craters will already have
degraded. It will also have become difficult to detect anything in the urine of
inhabitants in the outskirts of Damascus. Perpetrators will have had days to try
to cover up proof of the attack, experts said.
Ralf Trapp, a disarmament
expert who worked for the Organisation for the Prohibition of Chemical Weapons,
which is supplying experts to the UN team, said traces of chemicals in a
victim's urine fade within days, though blood could contain traces for
"They should be collected as soon after the incident as possible,
preferably within a couple of weeks after the alleged use," Trapp
In a conflict that is dividing world powers, inspectors will also
have to safeguard the integrity of the samples.
They have to make sure
containers and vials transported to the laboratories for analysis follow a
strict chain of custody, with fibre-optic seals and accompanied by exhaustive
documentation "to be able to demonstrate that the samples have not been tempered
with", Trapp said.
Samples should be sent to two or preferably three
designated laboratories from among those in the 20 countries with which the OPCW
has working agreements.
Jean Pascal Zanders, an independent expert who
runs chemical weapons blog www.the-trench.org
, said other sources of evidence,
such as witness interviews, could also be used to support claims of a
large-scale chemical attack.
"We're looking at such a large number of
people reported to have been affected by the chemical attacks. People would have
a narrative, and those narratives when compared with each other would be able to
build up a picture of what has happened," he said.
Autopsies are another
option, he said, but under Muslim tradition, the dead are buried within 24
hours, and families would have to grant permission for the remains of their
relatives to be exhumed.
As Monday's shooting showed, there is more to
the mission than science alone.
Per Runn, a Swedish chemical weapons
expert who worked with Sellstrom and is a former branch head at the OPCW, said
one of the major hurdles will be access to areas under rebel control, where the
Syrian government cannot provide security guarantees.
"I do not envy
Ake's position. As the person on the ground for the UN, he is the one who will
have to make the decision whether it is safe or not to go," Runn told
"He will face criticism no matter what he does. If something
goes wrong, he will be criticized for taking risks. If he refuses to go, he will
be criticised for being too cautious. He's caught between more than a rock and a
hard place," he said.