Cant it become airborn?
Are You a Terrorist?
If someone started engineering the actual virus: YES; otherwise, it required a numbers of mutations to become airborn-transmissible.
I can only imagine what kind of fun airborn stuff area 51 has after half a century of research in complete secret from the public. Also how did the CI..... HIV virus start? Airborn is definetly possible considering what kind of stuff the USA has done in the past.
EDIT: China propably have a lot of fun stuff too as well as Russia, but I dont think US, RU or CH are going to release an airborne version of the virus... Once you know biology and chemistry it's not that hard (I don't know either of those very well), evil people run this world and they will be up to shady stuff, but killing us off wont happen anytime soon. Also are you one of the people who thinks that the terrorists are muslims in 95%+ of the cases?
I read once the most dangeuros and common hazard there was the dumping of exotic materials & other byproducts in open pits to burn. I don't know if it's an enduring practice. However if they do BW research or manufacturing they'll use (i doubt, but i can disprove it with Open-Source docs) they will surely protects their workforce since people with PhDs cost a lot more to replace than Lumberjacks.
Industrial accidents in the BW plants already occurred and get known. Accidents in Soviets'programs, .