How do you figure? Biological weapons have to be cultured, and its not like you can purchase the agent on the open market. Anthrax is not easy to grow: it requires tight environmental control to get significant yield (enough to make a weapon). Chemical weapons must be manufactured in a processing plant. Mustard gas and other blistering agents, although chemically simple, require a processing plant to yield enough to make a weapon.
A gasoline (call it napalm) bomb requires... well… gasoline.
Glassware full of a substance to feed the critters is all that is needed. Biology texts provide more than just clues to this. Simple observations under a microscope allow process tuning. Temperature and pressure controls are extremely simple; and, can be excercised by humans using simple gauges and valves. A starter culture can be obtained from a sick critter or human. There are plenty of sick critters and humans in third world countries where inoculations are not commonplace. Strength of the biological agent is increased by taking a culture from an entity that was killed with the preceding strain.
Chemical weapons must be manufactured in a processing plant
Such plant is a great deal easier to build than a steel mill. Biological agents could be cultured in a plant that is easier to build than a steel mill.
Mustard gas and other blistering agents, although chemically simple, require a processing plant to yield enough to make a weapon.
What was the state of industry during WWI? Probably not much more advanced than might be found in any country with electric power. Quanity is "production rate" integrated over time.
The resources of a nation can be coordinated to some astounding results, even in relatively "primative" situations. The resolve of an enemy can usually overcome most anything. By consulting the CIA web page regarding Afghanistan, one can determine that they do have some resources. They also have money. Remember that Afghanistan is not the only nation that houses our enemies.
http://rense.com/political/weapons/newwarn.htm
I'll dredge up some more sites that indicate the reasonable fear of bio-terrorism. There are oodles of them.