The Syrian government’s reported use of sarin in its war against rebel forces is ominous. It suggests dissemination of the nerve agent could become more frequent there — whether by the Syrian military or by opposition forces in possession of captured stockpiles. If this happens, many more people will likely suffer the tortured effects of the chemical.

This could weaken the international taboo against such weaponry. No wonder President Barack Obama has warned that Syrian President Bashar al-Assad’s use of sarin would be a “game changer.”

For sarin is considered a weapon of mass destruction. As with all chemical agents, effectiveness depends on the purity, the means of dissemination and vulnerability of the exposed population. At worst, chemicals can be devastating agents of death, even if less expansive in their effect than a biological release or a nuclear detonation.

A drop of liquid sarin can be lethal after skin contact or inhalation of its vapor. The colorless, odorless material blocks the transmission of impulses between nerve cells, which effectively paralyzes the organs of the body, including the lungs. Asphyxiation and death can result within minutes.

Unlike a biological agent, such as the bacterium that causes plague and can lead to an epidemic, a chemical does not pose the danger of an infected person transmitting the disease to others. Nor does a chemical release threaten the massive destruction and widespread radiation that would result from a nuclear explosion. Still, the effects of a chemical attack can be horrendous.