Unable to find a country willing to dispose of Syria's chemical weapons, the United States is considering dissolving or incinerating the weapons' chemical components on a barge, according to senior US officials.
The two systems under review are intended to destroy the materials that are designed to be combined to form chemical munitions. Syria's smaller arsenal of operational chemical weapons would be destroyed separately, officials said.
Officials from the Organisation for the Prohibition of Chemical Weapons, working in Syria to find and identify the weapons, would monitor the destruction. The destruction would be carried out following safety standards set by legislation in the US and the European Union, according to officials familiar with the proposal. Officials did not say whether any chemical residue would be dumped in the ocean.
The seaborne options have received more serious consideration after Albania on Friday turned down a US appeal to destroy the weapons on its territory; the decision followed street protests by thousands of Albanians.
Norway rejected an earlier request, saying it did not have the expertise or the facilities to destroy the weapons. The issue caused a major political dispute there as well.
Under one plan, five incinerators operating aboard the barge would destroy all of Syria's most serious precursor materials for chemical weapons in fewer than 60 days. Officials said the byproducts would be harmless salts and other solids.
No US companies, ships or personnel would be involved under this proposal, although officials said it may be possible that the US military would help provide security in international waters.
The second proposal focuses on a highly sophisticated mobile system developed by the Pentagon, known as the Field Deployable Hydrolysis System.
It is designed to convert chemical agents into compounds that cannot be used for military purposes by mixing them with water and other chemicals and then heating them, US officials said.
The Pentagon says the system would neutralize the large quantities of precursor chemicals that could be used by the Syrian government to make sarin and other forms of poison gas.
Another senior official said the option of destroying the munitions at sea was "logical".
"There's convincing evidence that these options would render the chemicals neutral at sea," said the official, who spoke on the condition of anonymity because the final means of destroying the chemicals has not been decided.
By destroying the weapons in international waters, the effort would not require approval by any particular country, but environmental activists might voice opposition.
Syria has agreed to a deadline of December 31 for destroying the most critical material and February 5 for most of the rest.