As difficult as it may be to reach a diplomatic solution to avert a U.S.-led attack on Syria, the details of enforcement are also complex and uncertain, people with experience of monitoring weapons facilities said.
Spread far and wide across Syria, the chemical weapons complex of the fractured state includes factories, bunkers, storage depots and thousands of munitions, all of which would have to be inspected and secured under a diplomatic initiative that President Barack Obama says he is willing to explore.
But monitoring and securing unconventional weapons have proved challenging in places like Iraq, North Korea and Iran -- even in peacetime. Syria is bound up in the third year of a civil war, with many of the facilities squarely in battlefields.
"I'm very concerned about the fine print," said Amy E. Smithson, an expert on chemical weapons at the Monterey Institute of International Studies. "It's a gargantuan task for the inspectors to mothball production, install padlocks, inventory the bulk agent as well as the munitions. Then a lot of it has to be destroyed -- in a war zone."
"What I'm saying is, beware of this deal," Dr. Smithson added. "It's deceptively attractive."
As difficult as it may be to reach a diplomatic solution to head off a U.S.-led military strike on Syria, the details of enforcement are themselves complex and uncertain, people with experience of monitoring weapons facilities said.
Syria would first have to provide specifics about all aspects of its chemical weapons program. But even that step would require negotiation to determine exactly what should be declared and whether certain systems would be covered, because many delivery systems for chemical weapons -- including artillery, mortars and multiple- rocket launchers -- can also fire conventional weapons.
Then, experts said, large numbers of foreign troops would almost certainly be needed to safeguard inspectors working in the midst of the civil war.
"We're talking boots on the ground," said one former United Nations weapons inspector from Iraq, who spoke on the condition of anonymity because he still works in the field on contracts and did not want to hurt his chances of future employment. "We're not talking about just putting someone at the gate. You have to have layers of security."
Destruction and deactivation of those weapons could then take years.
The Obama administration is skeptical about whether this approach might work. A senior administration official called securing chemical arms in a war zone "just the first nightmare of making this work."
A Pentagon study concluded that doing so would take more than 75,000 troops. That rough estimate has been questioned, but the official said it gave "a sense of the magnitude of the task."
Another puzzle centers on arms movement. As President Bashar al- Assad has lost territory, or has feared that rebels could seize the lethal stockpile, he has consolidated his chemical weapons, administration officials say. Thus the old estimate that intelligence agencies offered -- of 42 separate chemical sites -- may no longer hold true.
"We only know a good deal about 19 of them," said another senior official who has been briefed on the intelligence. Thus, doubts could fester on whether Mr. Assad had turned over his entire arsenal.
Specialists in ordnance disposal and demilitarization say any effort to account for Syria's chemical weapons would require huge investments of resources and time, and the likely assumption of battlefield risk. The United Nations already has 110 chemical inspectors stretched thin around the globe, and their ranks would have to swell.
"I suspect some casualties would be unavoidable," said Stephen Johnson, a former British Army chemical warfare expert who served two tours of duty in the Iraqi desert. "The question you have to ask is whether the benefits would be worth that kind of pain."
These are not, experts noted, theoretical issues that may arise, but hard realities. …