According to scientists, evidence of the use of sarin, a nerve agent that originated as an insecticide but is now deployed in chemical warfare, can be detected years after an attack. This would mean that no matter how much Syrian President Bashar al-Assad denied his use of chemical weapons, experts would be able to find proof if he had launched such an assault. In the past, it was difficult to obtain results from these type of probes, but thanks to the many inquiries the United Nations has led over the years, the chemical signature of such agents has become easier to discern. However, investigators still face a series of problems with regard to the massacre in Syria.

The New York Times elucidates:

Identifying the exact makeup of toxic chemicals, especially in the field under less-than-ideal conditions, can be a tricky process rife with false alarms. But sending the field samples to distant laboratories for more thorough analysis can typically provide unambiguous answers to warfare allegations.

[Toxicologist David H.] Moore said his own judgment of the Syrian situation, based on viewing pictures of the victims, was that the crippling and killing “clearly looks like the work of a nerve agent.”

But he also said the United Nations inspectors could be confounded if, a week after the attack, the “worried well” presented vague symptoms but no solid evidence of chemical exposure.

“The further you are from an incident,” Dr. Moore noted, “the more difficult the investigation will become.”

Another hurdle, experts note, is that Syria has been shelling the area of the massacre in what Secretary of State John Kerry on Monday described as an attempt at “systematically destroying evidence.”

The clock may be ticking not only on environmental clues in Syria, but biological ones as well. Ron G. Manley, a former British military specialist and director of verification for the Organization for the Prohibition of Chemical Weapons, said studies had shown that the human body eventually metabolizes traces of nerve agents, erasing the chemical evidence.

However, the best indicators can be found in blood and tissue samples, and some British scientists have found that chemical traces will last in “blood and urine samples up to two weeks” after an attack. If Assad did in fact unleash chemical agents, in violation of the 1993 Chemical Weapons Convention, he won’t be able to hide from the scientific truth.

—Posted by Natasha Hakimi

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