By Anthony Deutsch

AMSTERDAM (Reuters) - There are no easy answers and a striking lack of precedents when it comes to the practicalities of destroying Syria's stockpile of poisonous munitions, one of the largest in the world.

The international body that would take on the task, if it is ever finalized, has never shipped such weapons abroad to be destroyed, because of the risks of transporting them, and it is not clear where they could go.

Neither, however, has it ever sent inspectors into a war zone for a cleanup operation.

Burning vast quantities of toxic chemicals alone is time consuming and risky. Separating them from ammunition in pre-loaded weapons is something else entirely.

Weapons experts believe Syria has a thousand tons of lethal nerve agent spread across some 50 sites. No one knows how much of that total -- enough to fill 100 dump trucks -- is already inside munitions.

When treated alone, in what is known as a binary state, the chemicals have to be injected in small quantities into a furnace and burned, while the exhaust fumes are pumped through a series of filters.

If they are inside munitions, described as unitary, those treating them have to wear full-body protection suits, said Dieter Rothbacher, who helped dismantle Saddam Hussein's chemical weapons program in Iraq.

"You might have to manually handle the munitions and feed them in, or you may have to open the ammunition casings with explosives one after the other, like we did in Iraq, and suck out the agent with a vacuum pump," he said.

"It is much more dangerous and toxic."

LACK OF CAPACITY

When Syria applied to join the Organisation for the Prohibition of Chemical Weapons (OPCW) this week it created an international obligation to provide the scientific capacity, manpower and money to get the job done.

Aside from the risks posed by the civil war, which has killed more than 100,000 people, the country does not have the capacity to carry it out, like most of the 189 states that joined the 1993 convention.

Russia and the United States, both of which are still destroying their own vast chemical weapon stocks, are the only countries with industrial scale capacity to handle mustard, VX, sarin or cyanide-armed munitions.

But the import of chemical weapons is banned under U.S. law.

"The U.S. would not be in a position to take them on. Russia might be able to do so, but the logistics would be difficult. No other country has an operational destruction program big enough to accommodate the Syrian stockpile," said Ralf Trapp, an independent chemical weapons disarmament specialist.

Germany has a facility that destroys old chemical weapons at a rate of 70 tons per year, but it cannot handle nerve agents such as those Syria possesses. Even if it could, destroying them would take well over a decade.

"One would need something bigger and with a different pollution abatement system if the stockpile were to be hundreds of tons of nerve agent," Trapp said. "Building and commissioning would take a few years, destruction may also take a couple of years depending on capacity."

The most likely option is that a network of on-site destruction facilities would be built in Syria, similar to Russia, with the help of foreign government funding and possibly U.N. security.

They would typically have an incinerator and reactor, a holding area which will hold munitions to be destroyed and a storage site for bulk chemicals. They would also need a maintenance unit and decontamination showers.

The first deadline in the convention's strict regime gives Syria 60 days to report its entire program to the Organisation for the Prohibition of Chemical Weapons in The Hague.

Within weeks of that, OPCW inspectors will be sent to verify the accuracy of Syria's account. It will likely take months for a team of 15-20 inspectors, the composition of which must be agreed with Damascus, to take stock.

If Syria were found to be moving or concealing weapons, or impeding the work of the inspectors, that would violate the convention and could escalate to the U.N. Security Council, which might impose sanctions.

Chemical weapon destruction in Iraq has been halted due to upsurges in sectarian violence, so it is likely to take years before Syria would even begin the process.

The stockpiles could be temporarily stored at collection centers until hostilities ceased, but the sites would need to be guarded against theft by militant groups, a job that would tie down tens of thousands of international troops.

(Editing by Philippa Fletcher)