The United Nations is preparing to send a team to Syria to investigate whether chemical weapons were used earlier this month in a deadly rocket attack near Aleppo. Investigators are likely to face major challenges from establishing the facts in a war environment to carefully handling suspected chemical samples.
There were survivors of what the Syrian government says was a chemical weapon attack by rebels on the northern town of Kahn al-Asal.
Many of the people rushed to a hospital in nearby Aleppo had breathing difficulties but no obvious external wounds. Syrian authorities said a rocket hit the town and emitted a gas that killed about 20 people. Syrian rebels said government forces fired it.
At Syria's request, the United Nations is preparing to send a team to the area to determine whether chemical weapons actually were used for the first time in Syria's two-year conflict. But, the world body says the mission is not intended to assign blame on either side.
Leading the team will be Swedish scientist Ake Sellstrom, who says it will be difficult to figure out what happened in the midst of a civil war. "We will have to try to peel away what is rumor and hearsay, misunderstandings and so on by talking to as many people as possible, try to get a consistent picture," Sellstrom stated.
Diplomats say U.N. Secretary-General Ban Ki-moon wants the investigators to start work next week and have "unfettered" access to the scene of the attack.
But, Syria first will have to approve their composition and mandate.
The Netherlands-based Organization for the Prohibition of Chemical Weapons is expected to appoint a team of eight to 10 experts in chemistry and medicine.
Amy Smithson, a senior fellow of the Monterey Institute of International Studies, says the investigators have strict guidelines for how to collect suspected chemical samples and deliver them to specialist labs.
"What is going to be important for international credibility is that any samples be taken with a chain of custody that proves this is where this sample was taken, and that it stayed in a legal chain of custody to the point of analysis so that those results will stand up in front of an international legal court or the international court of opinion," she said.
Smithson says the investigators may find that commercial chemicals were used in Khan al-Asal -- rather than highly-lethal warfare agents like mustard or nerve gas, as seen here in a Russian stockpile that was destroyed voluntarily in 2002.
"The chemical weapons convention defines chemical weapons as those classic warfare agents and their delivery systems and any toxic chemical used for military purposes," Smithson explained. "So it does not matter if it is ethyl methyl [an industrial solvent] or VX, which is a nerve agent. You cannot cross that line."
Syria's rebel factions have denied using any chemical weapons in their battle to oust autocratic President Bashar al-Assad.
The Syrian government has never confirmed that it possesses chemical weapons. But aides to Assad have suggested that any chemical weapons they may have would be used against foreign aggressors, not Syrians.
Animal carcasses lie on the ground, killed by what residents said was a chemical weapon attack days earlier,Khan al-Assal Syria, March 23, 2013.
A general view shows Khan al-Assal near where residents say a March 19 chemical weapon attack occurred.
Residents and medics transport a Syrian Army soldier, wounded in what they said was a chemical weapon attack near Aleppo, to a hospital, March 19, 2013.
People breathe through oxygen masks as they are treated at a hospital in Aleppo, March 19, 2013.
A general view shows the site near Aleppo where residents say a March 19 chemical weapon attack occurred.