WHADI KHAN, Iraq—There was still disagreement and uncertainty Monday about 14 barrels of an unknown substance found Saturday at a weapons site a few miles northeast of Baiji, Army leaders said.
Initial military field tests with a mass spectrometer indicated the presence of cyclosarin and a blister agent, but some military officials later said the substance could be as benign as rocket fuel.
A second battery of tests performed Saturday afternoon didn't rule out chemical weapons as similar tests have in the past, but didn't confirm their presence, either. Army chemical experts said two of the tests indicated the presence of a nerve agent and a third test, designed to distinguish chemical weapons from industrial chemicals, was inconclusive.
"We are still continuing our tests to see what we have," Gen. David Rodriguez, the assistant division commander of the Army's 4th Infantry Division, said Monday. "I know the last word was it could be rocket fuel, but it's gone back and forth on what this actually is."
Numerous false reports have turned up the pressure on U.S.-led forces to find chemical or biological weapons, the Bush administration's main justification for overthrowing Saddam Hussein's regime.
"I remain confident they will be found," British Prime Minister Tony Blair said in London on Monday.
Special operations soldiers found the barrels on about a 1.5-square-mile site along with 36 SA-2 anti-aircraft missiles, two lab trucks and a warehouse containing hundreds of gas masks that appeared to be of a higher quality that those found at other sites.
When testers from the 1st Squadron of the 10th Cavalry Regiment tested a second sample from one of the barrels with a mass spectrometer Saturday, the test showed a level of 6.5 for a type of nerve agent called cyclosarin. Testers are taught that any level above 4 is considered a strong indicator of an agent, Lt. Valerie Phipps said.
She said the spectrometer was accurate about 98 percent of the time. Those results prompted the Army to dispatch two more teams to the site. The commander of one team said afterward that the site was the most promising he had seen since the war began.
But another team, called the Mobile Exploitation Team, almost immediately dismissed the find as rocket fuel, before Phipps had a chance to explain her findings. Phipps said she was unclear how the team had reached its conclusion. The team, composed of Defense Intelligence Agency officers, CIA officers, FBI agents and biologists, is one of several with the Army's 75th Intelligence Exploitation Task Force.
Field lab tests probably can't distinguish reliably between commonly produced nerve agents and quick-acting insecticides, both of which are organic phosphorus compounds, said George Parshall, a retired director of chemical science for DuPont.
"They may have mass spectrometers, but I doubt they have the degree of resolution—in other words, the measurement of detail—that would be needed to give you a clear distinction," he said.
Conclusive testing would require a kind of chemical fingerprinting in a laboratory: separating the chemicals with liquid or gas using a process called chromatography, then breaking apart the molecules through a process called high-resolution mass spectrometry. Scientists then match the chemical fingerprint in a database of more than 1 million known agents, according to Parshall.
"If you have detailed analyses on the material, you could easily tell if it's a nerve agent, because a nerve agent would have specific characteristics not found in agricultural chemicals," Parshall said. "That would take more work than you can do in the field."
He also said it was unlikely that anyone would combine a nerve agent and a blister agent to create a weapon, because mixing the two made the nerve agent less effective.
Typically, chemicals found at suspected weapons sites have been brought to the United States for more conclusive tests. Pentagon and U.S. Central Command spokesmen wouldn't say Monday whether samples had arrived. Lt. Col. Dan Stoneking at the Pentagon said there was no timetable on the testing process. He wouldn't say what tests would be conducted.
"There won't be any rush to get it done. It's going to take some time," said Navy Lt. Col. Charles Owens, a spokesman at Central Command forward headquarters in Doha, Qatar.
(Knight Ridder Newspapers correspondent Tony Pugh contributed to this report.)
(c) 2003, Knight Ridder/Tribune Information Services.