As members of the international community condemn the horrific chemical attacks on the suburbs of Damascus, Syria that began Aug. 18, the past few days have cast a spotlight on the mechanisms behind chemical warfare. The recent series of events in Syria have reopened an analysis as to what exactly makes chemical weapons so much more immoral than those employed in conventional artillery warfare.

Why the distinction between ‘chemical’ and ‘conventional’ arms? 

Chemical agents conjure a certain psychological terror among civilians in part due to the entirely indiscriminate nature of gas attacks, and the fact that often no smell, sight, or even sound precedes the victim’s imminent death. If not a clean death, the sheer physical brutality of chemical maiming is cruel and usually carries long-term generational and environmental effects.

Often referred to as the ‘poor man’s weapon of mass destruction,’ critics, such as political scientist Dominic Tierney claim Western powers are quick to condemn the use of chemicals due to the vast array of powerful and expensive conventional arms these countries hold at their advantage.

“In fact, people likely die more quickly and in less pain from sarin poisoning than if they bled to death from a shrapnel wound,” said Stan Brown, a chemistry professor and chemical weapons expert at Queen’s University in an interview with the National Post.

Still, there is a remarkably low technological and monetary barrier preventing rogue actors from obtaining chemical weaponry in very large quantities. Many technologies, equipment, and materials used throughout the world for civilian purposes can easily be gathered to produce and manufacture chemical weapons agents, and there lies its greatest threat. An artillery shell the size of a suitcase full of sarin gas is lethal enough to kill an entire football stadium of civilians—a much greater effect than explosives of equivalent size.

By understanding the biological mechanisms of these chemical agents, research quickly illuminates why and how chemical weaponry pose such a threat.

Sarin gas

Widely suspected as the chemical employed in Damascus last week in the killing of 1,500 civilians, sarin gas affects the nerve endings of victims’ muscles through the nervous system. Eyewitness’ accounts of the recent attacks relay harrowing images of children running from their houses, convulsing, and gasping for breath before collapsing to the floor. Typically, sufferers experience frightening symptoms, such as foaming at the mouth and violent full-body convulsions. At high enough doses, sarin ultimately results in asphyxiation.

Under normal conditions, nerve cells release the neurotransmitter acetylcholine, a molecule that transmits signals from neurons to cells, to stimulate the muscle. The neurotransmitter crosses a tiny gap, known as a synapse, binding to the surface of adjacent muscle cells in order to excite the tissue and facilitate muscular movement. Then the enzyme acetylcholinesterase quickly degrades the acetylcholine in the synapse to prevent overstimulation of the cell, and relax the muscles.

The chemical compound, sarin, inhibits acetylcholinesterase. Therefore, when sarin gas enters the nervous system, it prevents acetylcholinesterase from degrading acetylcholine. A dangerous build up of acetylcholine can occur within minutes, resulting in a continual excitatory response in the muscles. This stimulation causes muscle seizures and impairs the respiratory system, ultimately resulting in respiratory arrest and the victim’s death.

In addition to its use in Damascus, sarin gas was employed in Iraq by Iraqi military forces against the Kurds in the 80’s, along with a number of cult terrorist attacks in Japan in the 90’s in an effort to bring down the government and install the group’s founder as the ‘emperor’ of Japan.

Mustard gas

Sulfur mustard carries an odor resembling that of mustard plants or horseradish; it is a potent vesicant—a chemical agent that produces blistering on exposed skin and mucosal membranes.

Often, mustard gas is used medicinally in wart removal. However, ingestion of even a very small amount of the compound can be fatal, leaving soldiers and civilians with painful internal and external disfigurations.

Upon entering the body, the chemical reacts with the water surrounding the body’s cells and loses a chloride ion, leaving behind an ion intermediate that reacts quickly with a number of enzymes and proteins on cell surfaces. Since this chemical process occurs most quickly in warm, moist conditions, the mucous membranes, eyes and respiratory tract are the most affected areas of the body. However, much is still unknown about the exact mechanism of tissue injury. The chemical can also mutate nucleotides—organic molecules that form the basic building blocks of DNA; this explains the long-term carcinogenic properties of mustard gas.

Since its first use in World War I, documented mustard gas use includes the Iran-Iraq war in 1984. In recent weeks, French intelligence has accused the Syrian Assad regime of having stockpiled 1,000 tonnes of both sarin and mustard gas, but this claim is still under much contention.