“On June 20th, 2015, The Independent ran an article entitled: “ISIS Dirty Bomb: Jihadists have seized Enough Radioactive Material to build their First WMD." Adam Withnall reports: "The ISIS militant group has seized enough radioactive material from government facilities to suggest it has the capability to build a large and devastating "dirty" bomb, according to Australian intelligence reports. ISIS declared its ambition to develop weapons of mass destruction in the most recent edition of its propaganda magazine Dabiq, and Indian defense officials have previously warned of the possibility the militants could acquire a nuclear weapon from Pakistan. According to the Australian foreign minister Julie Bishop, NATO has expressed deep concerns about the material seized by ISIS from research centers and hospitals that would normally only be available to governments." Withnall goes on to report in his article that: "The threat of ISIS's radioactive and biological weapon stockpile was so severe that the Australia Group, a 40 nation bloc dedicated to ending the use of chemical weapons, held a session on the subject at its summit in Perth last week."
According to a post on Nuclear Security Matters, a Harvard University site, Nate Sans posits in his article entitled: How much of a Nuclear, Chemical or Biological Threat Might ISIS Pose (Part II)? "ISIS may have the monetary means and the necessary equipment to organize and carry out a sophisticated attack in another count; therefore there is a real danger that they might be able to seize CBRN materials or tech, or inflict catastrophic damage to a facility such as a nuclear power plant. It is worth noting that ISIS includes hundreds of fighters from Europe and North America, who can travel in Europe and the United States without needing a visa."
National Defense published an article recently which, if true, provides a bit of insight on IS biological weapon aspirations and capabilities. In "ISIL Determined to Acquire Biological Weapons," Sara Sicard writes: "Intelligence has recently discovered that ISIS intends to pursue biological agents and also is trying to figure out how to weaponize bubonic plague through the use of infected animals," quoting Brig. Gen. Maria Gervais, Gervais is head of the Army's Chemical, Biological, Radiological and Nuclear School."
It would appear given ISIS, like Al Qaeda's quest for BW is underway. The difference with ISIS is they have the financial means to attract and acquire higher level scientists and control areas where they could test it possibly on human subjects, thereby forgoing the need to waste money on developing animal models and could effectively deploy it in a mass casualty scenario.
The capability issue is a concern should they overtake the SSRC in Damascus and install a scientific team with knowledge of synthetic biology. Much of the research undertaken at the SSRC is research into novel pathogens and deployment techniques. This would give ISIS a state warfare capability. I believe they are currently interested but not capable. With chemical warfare agents they are already using it and should they acquire VX or sarin both in Assad's former declared stockpiles they could easily transport this over land to Europe and deploy it around a city center. Governments generally downplay the ease of use but in fact CW in smaller quantities transported by several couriers with EU passports would be doable.
BW is even easier as the quantity doesn't matter as much as the quality of pathogenic agent and some agents don't need to be weaponized. The first deployment of a biological warfare agent in Europe will be a wakeup call to all states who continue to believe they are for some reason exempt from such attacks. The real risk any ISIS WMD program posses to Europe is the dismissal by European governments that such an attack would ever occur. It is the denial and disbelief that ISIS could possess such a capability and their intent to use it which is the biggest threat to European populations.”