Target

• A single chemical-weapon strike in a major city like New York or Chicago could kill tens of thousands.

• Half a milligram (a pinprick-sized dose) of Sarin will kill an adult. Cyclosarin is even more durable and deadly. One metric ton dumped into a reservoir, river or the ground would take thousands of lives.

• A 10-kiloton nuclear explosion would require less than half a pound of fissionable material.

• Single or coordinated nuclear attacks in major American metropolises using common means of delivery (such as vans, suitcases or cargo containers) could kill around a million apiece. Indirect implications would be exponentially greater than 9/11 as panic spreads; telephone, information and transport networks are destroyed; power grids blink out; and riots ignite.