While chemical and biological weapons are considered weapons of mass destruction (U.N. Resolution 687) and their use banned by international law (Chemical Weapons Convention, 1993), they are nevertheless a present threat. A United Nations report released September 16 confirmed that rockets loaded with sarin gas were used in the Syrian civil war August 21 against civilians in the Damascus suburb of Ghouta. The U.N. called the attack a war crime, but stopped short of saying who was responsible. The United States, however, places blame on forces loyal to the ruling regime of President Bashar al-Assad. Over 1,400 civilians died in the attack, including over 400 children.
An attack by terrorists using chemical agents is generally considered to have a low-probability, due to the difficulty of manufacturing, storing, and delivering the agents. According to the Stimson Center's Chemical and Biological Weapons Nonproliferation Project, it would take 18 years for a basement-sized operation to produce the more than two tons of sarin gas that the Pentagon estimates would be necessary to kill 10,000 people, assuming the sarin was even manufactured correctly.
Still, prudence demands readiness. The potential consequences of a biochemical attack are sufficient to justify appropriate first responder preparation and response protocols, particularly since there is concern that terrorists could just steal an existing stockpile and avoid the bother of making it themselves. It is feared that al-Qaeda groups fighting in Syria, for instance, could exploit Syrian government instability and seize the Syrian chemical agent stockpile.
It is therefore important that readiness includes making the latest chemical weapon detection technologies available to domestic law enforcement agencies. Law enforcement personnel will likely be on the scene of any reported chemical weapon incident, performing everything from initial investigation and evidence collection to perimeter control and site access.
Fuhrer's technology may eventually be among those in the hands of law enforcement. He claims it is highly efficient, with a sensitivity superior to the best existing detectors. Plus, he says, it operates up to 1,000 times faster.
One problem he admits is, superconducting detectors must currently operate at low temperature. While the UM superconducting detector can operate at somewhat higher temperatures (about -420 F) than existing superconducting detectors (about -460 F), it is still a low-temperature device that requires a cooling system that currently precludes widespread first responder or homeland security use.
However, Fuhrer says the UM team is currently working on a new graphene detector scheme designed to operate at room temperature and be significantly more sensitive than state of the art detectors.
Foam sweet foam
Better explosive detection is also exploiting the special properties of graphene. New research shows that graphene foam out-performs existing gas sensors in detecting the chemicals used in making explosives.
The discovery, at Rensselaer Polytechnic Institute, may open the door for a new generation of sensors that can be used by airport screeners, police bomb squads, and defense organizations. The RPI graphene sensor has demonstrated proficiency at detecting trace amounts of explosive chemicals such as ammonia and nitrogen dioxide. So far, the sensor has shown to be significantly more sensitive at detecting these chemicals at room temperature than currently available commercial gas detectors. Ammonium nitrate mixtures are favorite ingredients of car and truck bombers. Also, a nitrogen-based fertilizer known as anhydrous ammonia was responsible for the April fertilizer plant explosion in West, Texas.
Explosive detection is currently commonly used in airport, port and border control settings.
“Our sensor can detect ammonia and nitrogen dioxide at the parts per million level at room temperature,” says RPI engineering professor Nikhil Koratkar.
Koratkar says he believes the foam may prove to be more sensitive compared to conventional gas sensors. Koratkar found when graphene foam is exposed to air containing ammonia or nitrogen dioxide molecules, the gas particles adhere to the foam’s surface, changing its surface chemistry. This change affects the electrical resistance of the graphene. When measured, this change in resistance is the mechanism by which the sensor indicates the presence of different gases.
Many police agencies use specially trained dogs to detect explosives. The dogs have been trained to use their sensitive noses to locate scents of explosive ingredients. This method is effective until the dog tires or gets bored.