As diplomats wrangled over competing plans for securing Syria’s chemical weapons, arms-control experts warned Tuesday of the formidable challenges involved in carrying out such a complex and risky operation in the midst of a raging civil war.

U.N. teams dispatched to Syria for the mission would be attempting something new: finding and safeguarding a long-
hidden arsenal in a country that has long stood outside key international arms-control agreements — all while exposed to crossfire from Syria’s warring factions.

Although the mission might be worth the risks, experts say, it would be costly and time-
consuming, especially if the goal included the physical destruction of what is estimated to be thousands of chemical warheads and rockets as well as hundreds of tons of liquid toxins kept in bulk storage throughout Syria.

“It is doable, and potentially a great idea, but let’s not be naive,” said Jean Pascal Zanders, a Belgian arms-control researcher and writer for the Trench, a blog focusing on weapons of mass destruction. “If you can get around the legal and logistical questions, securing the stocks might be relatively easy to achieve. But if you add destruction of the munitions, you have to think in terms of years.”

Syria is thought to possess the third-largest chemical weapons stockpile in the world, after the United States and Russia, which are in the process of destroying theirs. Syria’s arsenal is thought to include sizable amounts of the deadly nerve agent sarin, as well as mustard gas and other toxins.

But until now, the Syrian government had never formally acknowledged its chemical weapons program. That changed Tuesday when Syrian Foreign Minister Walid al-Moualem said his country is prepared to sign the international treaty governing chemical weapons, to make the location of its chemical arms facilities available to international observers and to dispose of the weapons.

The sudden commitment to openness was greeted warily by Western analysts, who noted the habitual secrecy of President Bashar al-Assad’s regime. That tendency could further complicate the task of U.N. teams seeking to lock down as many as a dozen sites used for manufacturing, storage and battlefield preparation, weapons experts said.

An involved mission

Several previous international missions during the Syrian conflict have been notable failures, partly because the Assad government refused to grant access to sensitive sites and partly because spiraling violence put the foreign teams at risk.

Much remained unclear Tuesday about how — or even whether — chemical weapons inspections would occur. But several diplomats stressed the importance of a buy-in from all sides, including Assad and key rebel groups. Alexander Kalugin, Russia’s ambassador to Jordan, said any plan must involve “international inspectors” — probably from the United Nations — as well as guarantees for their physical safety.

“We are now engaged with Syrians about working out some concrete details on how to do the job,” he said by telephone from Amman, the Jordanian capital. “It’s certainly not an easy mission.”

Assuming that the inspections get off the ground, a first order of business would be conducting an exhaustive inventory to ensure that all chemical munitions are accounted for. With solid numbers in hand, U.N. officials would probably seek to consolidate the arsenal into the lowest possible number of storage sites. Zanders, the arms-control expert, suggested that the weapons could be best stored near the port city of Tartus, where Russia maintains a naval base.

Zanders also argued for heavy involvement not only of Russia but also of Iran, another close Assad ally. Both countries are signatories to the treaty on chemical arms control, and he said their presence, despite Western suspicions, could help ensure Syria’s cooperation.

The final stage in the process — destroying Syria’s chemical arsenal — would be the most complex, requiring the construction of incineration facilities that must operate under exacting standards to prevent contamination.

The United States, which manufactured 31,100 metric tons of chemical munitions during the Cold War, launched a multibillion-­dollar program in 1997 to destroy its stocks. Sixteen years later, it has still not completed the task.

Potential difficulties

The experience of the team of U.N. chemical weapons experts who traveled to Damascus last month to investigate alleged poison gas attacks highlights the difficulties that any group of international inspectors would face.

The U.N. officials, who entered the country just days before an alleged Aug. 21 sarin attack killed an estimated 1,400 people, had been assured safe and unhindered passage by the Assad government. Yet, the inspectors’ convoy came under fire on its first day of field visits, forcing it to temporarily turn back. The government and rebels blamed each other for the incident.

Last year, Arab League and U.N. monitoring teams also cut short their missions in the country, citing escalating violence. The security situation has since worsened, with the addition of new al-Qaeda-linked factions on the rebel side and militants from the Iranian-backed Lebanese Hezbollah movement on the government side.

In a further risk for inspectors, the military bases that are thought to contain chemical weapons depots are in areas that have been a focus of intense fighting in recent months. One suspected production facility, the Safira base near Aleppo, has been the target of repeated rebel assaults.

There also are legal and logistical obstacles, weapons experts say. Syria is one of only seven countries that have not signed the Chemical Weapons Convention, so there is no internationally recognized legal framework for U.N. arms inspections to proceed. Some U.S. officials have called on the Assad government to quickly sign and ratify the weapons treaty as a way of demonstrating its good intentions.

But the true test of Assad’s sincerity may not come until inspectors are inside the country. Paul Salem, director of the Carnegie Middle East Center in Beirut, said the Syrian president could decide to keep part of his arsenal hidden, dragging inspectors into a cat-and-mouse game that would provide no real way of knowing whether stockpiles have been fully secured.

For now, however, Syria’s promises to allow access to its sites should be seen as a breakthrough, he said.

“It means they’ve effectively committed not to use chemical weapons again and directly or indirectly assumed some responsibility,” Salem said. “If the whole hubbub was to deter Syria, the fact that they’ve said they’ll put their chemical weapons under someone else’s jurisdiction — that’s an achievement.”

Morris reported from Beirut.