The foremost reason chemical weapon's sites will not be bombed in Syria is concern for the safety of civilians. The chemicals, if hit by a missile, could be released into the air. Sarin gas vaporizes quickly but mustard gas is different and even more insidious. When a person contacts mustard gas, it damages the skin, mucous membranes, inside the nose and throat. It is an alkylating agent which means its chemicals destroy DNA, cell, and liquefy tissue. Basically, it kills anything it touches.
The US and its allies do not want to use an intervention that could release these chemicals even accidently when the reason for the air strikes is to send the message to Syrian President Bashar Assad that chemical warfare is prohibited, most recently by the Geneva Protocol.
International actions against the use of chemical weapons
The international community has a history of declaring chemical weapons inhumane going all the way back to the 19th century. Some countries, however, have developed and used these types of weapons, and unfortunately the US is one of them with the use of Agent Orange in the Vietnam War.
Wikipedia lists some of the instances in which attempts were made to forbid chemical weapons.
The emphasis for the intervention is not to initiate a regime change, as the United States, France and Britain are united in sending a clear message to Assad that the use of chemical weapons will not be tolerated, according to a report in the Jerusalem Post.
President, together with our allies, has stated “there must be a response” to last week’s chemical weapons attack that killed civilians in Damascus. Jay Carney, White House press secretary, informed journalists of the president's views at a news conference Tuesday.
Diplomats at a meeting in Istanbul, Turkey, informed the Syrian government opposition leaders to be ready to negotiate with Assad if the Syrian president takes the air strikes, or even the advent of the air strikes, seriously and decides to trade violence for peaceful negotiations, according to a Reuters report.
US Secretary of Statesaid on Monday, ““This is about the large-scale, indiscriminate use of weapons that the civilized world, long ago, decided must never be used at all.”
The secretary’s comments were intended to lay the groundwork for the moral case for intervention, an American official told The Jerusalem Post.
“President Obama believes there must be accountability for those who would use the world’s most heinous weapons against the world’s most vulnerable people,” he said.
To those who might say a Western intervention is hypocritical because many countries have used chemical weapons, the United States has learned tragically through the unintended consequences of how devastating chemical weapons can be.
The use of Agent Orange had damaging effects on US veterans of Vietnam. Cancers of many types and skin and respiratory disorders, including leukemia, Hodgkin's lymphoma and non-Hodgkin's lymphoma, prostate cancer, lung cancer, colon cancer, soft tissue sarcoma and liver cancer have been diagnosed. The US Department of Veterans Affairs has determined these conditions may be associated with exposure to Agent Orange/dioxin, and are on the list of conditions eligible for compensation and treatment.
While countries that have used these heinous weapons before cannot change the past, they can certainly learn from it, which I believe the United States has done. As a country we know what happened to the Vietnamese people and to our veterans, and we don’t want to see the past repeated if we can prevent it and save lives.