All human life on earth could be ended by a single gallon of strategically-distributed anthrax. This fact, coupled with ongoing North Korean efforts towards weaponization has led experts, like the Obama-administration Pentagon head of nuclear, chemical, and biological defense programs, to declare that “North Korea is far more likely to use biological weapons than nuclear ones…the program is advanced, underestimated and highly lethal.” Biological weapons are uniquely enticing to countries like North Korea as they are significantly cheaper than nuclear weapons and can be more easily embedded within research on seemingly innocuous subjects like vaccines and agricultural research. Currently, the U.S. does not appear to know whether or not the country has produced bioweapons, or whether it simply has the means and technology to do so at a moments notice. Defectors from North Korea have claimed to have witnessed testing of various agents on prisoners.
While the US (1969) and most countries ended chemical weapons development, production, and usage, advances in gene manipulation has greatly expanded the possibilities these weapons offer. What research has been conducted on the topic suggests that North Korea has invested heavily into investigating these possibilities.
Source: North Korea’s Less-Known Military Threat: Biological Weapons – The New York Times