Make 100 teams of 3 agents (Iraqi or AQ), give them 100,000 or even 500,000 dollars and 5 litres of anthrax. Each team builds 5 devices (for about 10K each) and keeps them in a safe house (300,000 dollars for property and food).
We invade Iraq and 100 teams launch 5 of these puppies with a litre of anthrax in each from a rural area.
Even with 10% success rate SH's teams have just hit 50 cities with a litre of anthrax EACH for 50 million dollars in weapons deployment costs.
Don't say it can't be done.
All victims in the region take doxycilin and fully recover, attack fails.
Of all the things we need to worry about, this is pretty low on the list.