The chemical weapons that have been recovered by US forces in Iraq were all made before the 1991 Gulf War and were too degraded for their intended use, US intelligence officials said.
Republican lawmakers have cast the disclosure that about 500 chemical weapons have been found in Iraq as evidence that Saddam Hussein had a stockpile of the weapons before the March 2003, US invasion of Iraq.
But the intelligence officials, who briefed reporters on condition of anonymity, said the weapons were too degraded to have posed a threat to US forces in March 2003.
They said all chemical weapons found since 2003 were produced before the 1991 Gulf War and they had no evidence Saddam was producing or stockpiling chemical weapons after that.
"Generally they are in poor condition," one official said.
"We assess that they are not in condition to be used as designed. And detailed analysis of the toxic agents shows they are degraded and represent a much lower hazard," he said.
The munitions have been tested and computer simulation models created to determine what effect they might have under a variety of scenarios, the officials said.
Although not suitable for their intended purposed, the officials said such weapons remain a potential hazard if obtained by insurgents and modified in ways they would not discuss.
The officials, however, said they had no evidence that any element of the Iraqi insurgency has possession of chemical weapons.