(on edit: I was typing my post when your follow-up, with revised numbers, was posted)
Still want to stick with your "few tanker trucks worth" line?
At the UN, Colin Powell said:
"Saddam Hussein has never accounted for vast amounts of chemical weaponry: 550 artillery shells with mustard, 30,000 empty munitions and enough precursors to increase his stockpile to as much as 500 tons of chemical agents."
"If we consider just one category of missing weaponry, 6500 bombs from the Iran-Iraq War, UNMOVIC says the amount of chemical agent in them would be on the order of a thousand tons."
"Our conservative estimate is that Iraq today has a stockpile of between 100 and 500 tons of chemical weapons agent. That is enough agent to fill 16,000 battlefield rockets. Even the low end of 100 tons of agent would enable Saddam Hussein to cause mass casualties across more than 100 square miles of territory, an area nearly five times the size of Manhattan."
Remarks to the United Nations Security Council by Secretary Colin L. Powell, New York City, February 5, 2003
http://www.state.gov/secretary/rm/2003/17300.htmAnd of course, let's not forget what a great leader said during his state of the union speach:
"Our intelligence officials estimate that Saddam Hussein had the materials to produce as much as 500 tons of sarin, mustard and VX nerve agent. In such quantities, these chemical agents could also kill untold thousands. He's not accounted for these materials. He has given no evidence that he has destroyed them."
"U.S. intelligence indicates that Saddam Hussein had upwards of 30,000 munitions capable of delivering chemical agents. Inspectors recently turned up 16 of them -- despite Iraq's recent declaration denying their existence. Saddam Hussein has not accounted for the remaining 29,984 of these prohibited munitions. He's given no evidence that he has destroyed them."
State of the Union, January 28, 2003
http://www.whitehouse.gov/news/releases/2003/01/20030128-19.html