...
"..Jordanian authorities said the attack would have mixed a combination of 71 lethal chemicals, which they said has never been done before, including blistering agents to cause third-degree burns, nerve gas and choking agents. A Jordanian government scientist said the plot had been carefully worked out, with just the right amount of explosives to spread the deadly cloud without diminishing the effects of the chemicals. The blast would not burn up the poisonous chemicals but instead produce a toxic cloud, the scientist said, possibly spreading for a mile, maybe more..."
----------- See : "Jordan says major al Qaeda plot disrupted," http://www.cnn.com/2004/WORLD/meast/04/26/jordan.terror/index.html