I don't think that anyone seriously fears that the world can be blown to pieces all together. But what one can fear and rightly so are regional things, like in the Middle East, India, Pakistan, the Korean Peninsula, borders in Africa, etc.
Hans BlixThe nerve agent VX is one of the most toxic ever developed. 13,000 chemical bombs were dropped by the Iraqi Air Force between 1983 and 1988, while Iraq has declared that 19,500 bombs were consumed during this period. Thus, there is a discrepancy of 6,500 bombs. The amount of chemical agent in these bombs would be in the order of about 1,000 tonnes.
Hans Blix