As STRATFOR predicted in mid-May, the threat of a terrorist attack inside the United States is intensifying. U.S. counterterrorism sources are greatly concerned about an attack this summer, as demonstrated by the May 26 government warnings, and a global effort to disrupt attack plans with public alerts domestically and a concerted push for arrests and extraditions abroad. Passenger rail and subway systems remain vulnerable to Madrid-style attacks.
In addition to the detonation of conventional explosive devices on public transport, U.S. counterterrorism officials say the possibility for a chemical attack is increasing. Chemicals could be the weapon of choice among militant operatives.
This week, STRATFOR intelligence sources have expressed growing concern that militants might attempt to detonate a device to disperse toxic chemicals and cause mass casualties. STRATFOR believes the timing of a May 21 FBI alert about suicide bombers, together with the latest public warnings of possible al Qaeda attacks, underscores the idea that a militant plot could be unfolding within the United States. The suicide bomber alert cautioned about people wearing heavy or bulky jackets on warm days, smelling of chemicals or trailing wires from their jackets; it also alerted people to more subtle indicators, such as a person with tightly clenched fists, who could be gripping a device rigged to go off when pressure is released.
The FBI alert is a positive development for law enforcement and for those engaged in corporate security. As one source close to the matter told STRATFOR, "The details provide very good tactical information" to help sensitize law enforcement to a specific attack method by giving the physical descriptors of a suicide bomber. A suicide bombing could be the perfect attack against mass transportation systems, such as subways in cities such as Washington or New York. Such an attack could use conventional explosives or employ a chemical component.
At Risk: Public Transport and Chemical Storage Facilities
A major chemical attack inside the United States could create a public safety disaster on the scale of Sept. 11. An improvised explosive device (IED) could be detonated in close proximity to — or within — a chemical storage facility, or an IED containing a chemical agent — such as sarin — could be detonated, dispersing the toxic chemicals and causing mass casualties.
Sources within the U.S. counterterrorism community are concerned about such attacks. More than likely, chemical threat information has surfaced because of al Qaeda suspect debriefings, technical intercepts and analysis of al Qaeda's anticipated actions. Various seized documents demonstrate a significant interest on the part of al Qaeda planners and trainers in the potential for chemical attacks, although information on their actual capabilities is limited. Training manuals were found at al Qaeda training camps in Afghanistan, and some experimental training took place at camps in Chechnya and Georgia's Pankisi Gorge. Jordanian intelligence officials also claim an interdicted plot to attack intelligence service headquarters and the U.S. Embassy in Amman involved the detonation of a large "chemical bomb" that might have killed as many as 20,000 people. At least one arrested plotter backed up the chemical claims in a televised confession, though the reliability of the Jordanian claim remains questionable.
STRATFOR sources indicate that the potential for the detonation of radiological materials (a dirty bomb) has decreased somewhat, but still cannot be ruled out. Intelligence sources are specifically concerned about the potential for the release of a poison gas such as sarin, a highly toxic nerve agent that has been used in the past. At room temperature, sarin is liquid, but it evaporates quickly into a clear, colorless, odorless and tasteless gas that kills its victims by paralyzing the muscles surrounding their lungs, causing suffocation.
The release of a toxic gas on a crowded subway is one possible scenario. Aum Shinrikyo, the Japanese apocalyptic cult, used sarin in a 1995 Tokyo subway system attack, killing 12 people and sending more than 5,000 to the hospital. The cult filled plastic bags with the nerve agent and punctured them after they were planted in the subway. Mass transit systems in major cities such as New York, Boston or Washington are vulnerable to this kind of attack, which would be very difficult to guard against with any reasonable security measures.
Even though sarin can be made with commercially available materials, it is not easy to produce; a sophisticated laboratory is required to produce a stable and effective weapon. But other more readily available toxic chemicals could be used in a subway attack. The difficulties associated with securing, transporting and successfully deploying toxic chemical agents such as sarin could encourage militants to embrace another attack scenario: Targeting a chemical storage facility near a heavily populated area with the intent of releasing toxic chemicals against the surrounding population. Such a scenario has its own set of difficulties; it would be more difficult to carry out, with more variables for possible failure than an attack on public transport. Still, it is a troubling possibility.
Targeting Stored Chemicals
Chlorine and ammonia storage facilities near populated areas could become targets. Chlorine stores at water treatment plants are a top concern because they tend to be close to cities — and some locations have large stockpiles of liquid chlorine, the most viable form for a large-scale terrorist attack. A wide range of facilities have large stores of toxic chemicals, and determined terrorists could attempt to break through their security controls. Adopting tactics used in recent attacks in Saudi Arabia and the interdicted plot in Jordan, multiple vehicles could be used and operatives could shoot any visible guard force. Alternatively, an attack could come as an "inside job," similar to the May 1 assault on Western workers in Yanbu, Saudi Arabia.
A May 25 fire at a swimming pool supply warehouse near Atlanta — containing large quantities of chlorine — highlighted the impact an attack on a chemical storage facility could have. Tens of thousands of pounds of chlorine products were stored in the Biolab warehouse — located approximately 10 miles east of Atlanta — when an early morning fire started, resulting in a huge cloud of drifting, toxic smoke. Nearly 10,000 people live in the area of the warehouse, and sheriff's deputies went door to door, advising them to evacuate. Smoke caused the partial closure of Interstate 20 east of Atlanta and the removal of patients from a local hospital to another facility, beyond the smoke cloud's estimated five-square-mile reach. The wind pushed the smoke/chemical cloud away from the city of Atlanta. Although there are no signs of foul play in the Atlanta incident, the fallout from the accident highlights the danger if such a site were to be targeted for a well-planned operation.
Militants are presented with a ready supply of chemical materials, rather than having to risk gathering and storing them for later use. Members of sleeper cells might seek employment at such a business. Photographs of the Atlanta-area site reveal why these facilities create concern as potential targets: It is adjacent to a main road, with limited visible security in place and with trees and a water tower — which could provide cover to attackers — looming above its perimeter wall. This is one of many similar facilities near major metropolitan areas that could be vulnerable to a concerted attack. In the current threat environment, such facilities should, and likely are, enhancing their levels of security, particularly around their perimeters — and especially as intelligence worries over a chemical attack inside the United States continue to grow.