In the biblical sense.
One of the First Known Chemical Attacks Took Place 1,700 Years Ago in Syria
In approximately 256 C.E. Dura-Europas, a Roman fort known as “the Pompeii of the Syrian Desert,” fell victim to a Sasanian Persian siege in what is now Syria. When archeologist Simon James investigated the site several years ago, he found traces of yellow sulfur crystals and pitch near a pile of bodies—Roman soldiers who had died in the battle. This evidence points to a different kind of death for the 19 entombed Romans. As Discovery News reports, around 1,700 years ago, Syria was site to one of the first chemical gas attacks known in history.