Originally Posted by
KRSW
Does anyone know what the explosives detectors pick up on? I know nitrogen is at least one of the compounds being looked for -- my friend's wheelchair got the smurfs in a frenzy. Appears he rolled through recently-fertilized grass on his way to the airport.
Some kinds of fertilizers indeed will have particulate matter that will set off some types of ETDs.
[The air I breathe usually has way more nitrogen than oxygen.]
Originally Posted by
747FC
Your polemics do not negate the truth that one instance of a false positive as the OP experienced does not entail any security risk. A false negative presents a considerable one.
Polemics? No. I'm talking about the practice of encountering too many "false positives" having a history of generating complacency that ends up being a distraction that enables smuggling of contraband WEIs. [Think about the boy who cried wolf.]
If you have proof that contradicts the following:
Most "true positives" at screening checkpoints are taking place when there is no contraband WEI to be seized by the screeners. Just because a true positive match for certain molecules takes place does not mean there is necessarily a contraband WEI present to be seized/interdicted. That is why some say that "false negatives" are generally not as dangerous as the knee-jerk crowd believes the "false negatives" to be.
ETD means at airports are useful more for their deterrence impact than for effectively detecting and interdicting all possible contraband explosive means/devices that could seriously injure or kill people on planes.
then you should consider supplying the TSA with that (i.e. "the false negatives present a considerable risk" to flight security), as the TSA loves examples in an effort to try to justify their expenditures in the name of security. If you know how the various tools used for ETD actually work, then you realize that "false negatives" take place rather routinely. Sensitivity levels, my dear.
False positives for "explosives" do increase risk of security failures, as personnel performance is not static in the face of false positives.