In a February 2016 interview with 60 Minutes, John Brennan, director of the CIA, mentioned that the Islamic State (also known as ISIS) has, in a number of instances, “used chemical munitions on the battlefield.” This came a few days after James Clapper, director of the United States Intelligence Community, said to a congressional committee that ISIS “has also used toxic chemicals in Iraq and Syria, including the blister agent sulfur mustard.” Specifically, ISIS used such munitions in an August 2015 attack on the Kurds in Kobani, although reliable measures of the extent of the damage and casualties are not available.

It wasn’t the first time that such accusations have been raised against ISIS. In early 2015, the journalist Adam Withnall reported on Australian intelligence assessments that ISIS had “seized enough radioactive material from government facilities to suggest it has the capacity to build a large and devastating ‘dirty’ bomb.” In ISIS’ own magazine, Dabiq, John Cantlie, the kidnapped British war correspondent, telegraphed a warning that, with “billions of dollars in the bank,” ISIS could request that its operatives in Pakistan purchase a nuclear weapon, take it to Nigeria, and then smuggle it into the United States through Mexico by using existing drug- and human-trafficking networks. That might sound implausible, but the article at least indicated that ISIS is thinking along these lines.

And it wouldn’t be the first group. Terrorists, and in particular jihadists, have long been interested in the acquisition and use of chemical, biological, radiological, and nuclear (CBRN) weapons. And a number of extremist groups and individuals have either used or experimented with components of CBRN. In this context, and given the fact that ISIS could be in possession of some form of weapons of mass destruction (WMD) and has threatened to use them against the West, Western governments should take notice.

A Free Syrian Army medical group trains people on how to cope with chemical weapon attacks in Aleppo, December 25, 2013. Ammar Abdullah / Reuters FROZEN CONFLICT

Jihadist groups understand that they are locked in an asymmetric conflict with the West and that they cannot defeat the adversary in an all-out military confrontation. Their strength, they believe, is related to the West’s aversion to casualties. As Abu Bakr Naji, one of the prominent strategists of the jihadist movement, once claimed:

If the Americans suffer one tenth of the casualties the Russians suffered in Afghanistan and Chechnya, they will flee and never look back. That is because the current structure of the American and Western armies is not the same as their structure during the colonial era. They have reached a stage of effeminacy that makes them unable to sustain battles for a long period of time, a weakness they compensate for with a deceptive media halo.

Jihadists likewise know that racking up enough casualties to make the West back down could be a long process. “The struggle between us and them,” and “the confrontation and clashing,” as Osama bin Laden emphasized, “began centuries ago and will continue . . . until Judgment Day.” ISIS relies on the same rhetoric. As ISIS’ chief spokesman—Sheik Abu Mohammed al-Adnani—mentioned, “We will conquer your Rome, break your crosses, and enslave your women. If we do not reach that time, then our children and grandchildren will reach it.

For jihadists, then, keeping up the attacks is key. Strikes are demonstrations of competence and relevance that help bring in recruits and other forms of support. The nature of the attacks is equally important. They must offer good visuals, demonstrate organizational prowess, inflict heavy casualties and damage, create terror, and provide opportunities for heroism. But all that is hard to get right, which is why jihadists are generally tactically conservative, with a preference for tried and tested methods. Innovations do occur, as was the case on 9/11 and at other times. But a majority of the operations—such as the October 2000 attack on the USS Cole, the March 2008 attempt to take down a ChinaSouthernAirlines flight with liquid explosives, and the attacks in Paris (Charlie Hebdo shootings, January 2015) and California (San Bernardino, December 2015)—are copycat attacks.

DIRTY BOMB

So where does CBRN, arguably the least conservative of all weapons, come in?

Evidence found in 2001–02 in al Qaeda training camps in Afghanistan confirmed that the organization was interested in acquiring chemical and biological weapons as well as a radiological dispersal device, or “dirty bomb.” A 2003 statement from bin Laden and a fatwa the same year from prominent Saudi cleric Sheik Nasir bin Hamid al-Fahd legitimized the use of CBRN weapons. In a similar vein, al Qaeda spokesperson Sulaiman Abu Ghaith wrote that it is “our right to fight them with chemical and biological weapons, so as to afflict them with the fatal maladies that have afflicted the Muslims because of the [Americans’] chemical and biological weapons.”

In February 2003, the FBI warned that “al Qaeda and affiliated groups continue to enhance their capabilities to conduct effective mass-casualty chemical, biological, radiological, and nuclear (CBRN) attacks” and that al Qaeda possesses “at least a crude capability to use” such weapons. As we now know, al Qaeda never did manage to make much use of any weapons of mass destruction, but even in September 2010, Michael Leiter, then director of the National Counterterrorism Center, stated that despite successes in preventing terrorists from developing WMD capability, the threat of such terrorism remains a grave concern, primarily, according to Leiter, because al Qaeda and other groups continue to seek the capabilities.

Further, a number of al Qaeda affiliates—some of which now adhere to ISIS—did have more luck with CBRN weapons. The Salafist Group for Preaching and Combat, now called al Qaeda in the Islamic Maghreb, successfully developed ricin at underground labs in London. And reports suggest that ISIS, for its part, got hold of its own chemical and biological materials and weapons from stockpiles in Iraq, specifically at the Al Muthanna Chemical Weapons Complex, and in Syria, especially the chemical weapons that the regime of Syrian President Bashar al-Assad did not or could not destroy. It has also recruited experts from all over the world, including those who worked with Iraqi President Saddam Hussein and the Islamic University of Mosul in Iraq.

Syrian soldier aims an assault rifle from his position in a foxhole during a firepower demonstration, 1992. WikiMedia In all this, there is something of a contradiction between terrorist groups’ risk aversion and their interest in WMD. To be sure, violence and mass casualties are at the heart of terrorist operations, whether the deaths come via guns and improvised explosive devices or WMD. But until ISIS, actual CBRN seemed like a bad—or at least dangerous—bet. In other words, groups might have preferred to threaten to use such weapons and even stockpile them, while relying mostly on conventional tactics.

However, ISIS’ brand of terrorists could be less risk averse owing to the group’s extreme religiosity. Its claim that the great and final battle between infidels and Muslims will take place in Dabiq, Syria, preceding the Day of Judgment has not only attracted recruits in huge numbers but has stirred in them an apocalyptic fervor. And if ISIS successfully uses the weapons, it could teach other terrorist groups to do the same.

Cantlie’s hypothetical weapons purchases posed in Dabiq, and the statements and testimonies of intelligence agencies and political leaders, should be examined in this light.

ENTREPRENEURSHIP

Arguably, jihadist entrepreneurs are interested in experimenting with virtually anything and everything that could be used against the adversary. But weapons of mass destruction involve a high level of technological and scientific skill, equipment, materials, and organization. Acquiring nuclear weapons is extremely difficult, as is concealing a production facility or even the transportation of an actual weapon. Even though biological, chemical, and even radiological dispersal devices can be produced with relative ease and at a lesser risk of interdiction, there is still some inhibition about using them because of the risk that the attack will spin out of control—affecting not only the enemy but also their own supporters and co-religionists.

Here, for those worried about ISIS, the case of al Qaeda is instructive. Despite creating a dedicated WMD committee to develop, acquire, and weaponize CBRN materials at its sophisticated training camps in Afghanistan, in particular at Tanarak and Darunta (sarin and hydrogen cyanide, respectively) and Kandahar (anthrax), none of the programs were successful. Al Qaeda’s ambitious project for a nuclear or at least a radiological dispersal device was either a nonstarter or was short-circuited. Similarly, the Jemaah Islamiyah—an al Qaeda–associated group in Southeast Asia that is attempting to establish an Islamic state in the region and is responsible for a number of high-profile attacks, including the 2002 Bali bombings—launched a chemical-biological program, but it was very basic, with materials culled from the Internet. The program was ultimately shuttered.

The rarity of catastrophic attacks with mass casualties, or even planned attacks, reflects the difficulties in carrying them out successfully. And, to be sure, as RAND’s John Parachini put it, it can be hard to draw lessons about terrorists and CBRN because of the very “few historical cases of terrorist interest in and acquisition of CBRN weapons.” In other words, ISIS may have greater stockpiles of the materials for weapons of mass destruction, and it may have more willingness to risk using them. There is no reason, however, to think that it will have significantly more success in carrying out the attacks.

Even so, because the consequences of a CBRN attack would be so great, the West should not take ISIS’ forays into the area lightly. The United States and its allies must remain vigilant and try to preempt any attempt by groups such as ISIS or al Qaeda to develop or acquire and use CBRN materials. Ignoring the risk is too dangerous.