Any U.S. attack will probably involve materials concocted in a New York apartment from ingredients that are cheap, legal and easy to get.
In our last big undeclared war we measured progress in megatons that could hit targets 10,000 miles away. On the front lines today we have to sniff trillionths of grams of material at a range of 30 yards. Back then we faced a missile gap, or so we were told. Today we face the CBRNE gap, a horrifying disconnect between the enemy's ability to slip chemical, biological, radiological, nuclear or explosive material into a bottle or backpack and our ability to detect the stuff before it's released in a stadium or detonated in the subway.
We do know how to detect it--just not cheaply, accurately and unobtrusively, so that normal life can go on around us while we do. If trained dogs were as cheap and small as closed-circuit TV cameras and had been deployed as widely in London's stations and subways, there's a good chance the dogs would have picked up the signature smell of the highly volatile (and therefore odorous) explosive or of the acetone the bombers used to make it. If every British bobby patrolling the streets had been equipped with a supersensitive, watch-size sniffer on his wrist or strapped to his leg, one of them might well have picked up the scent of murderous chemistry before the backpacks ever left the row house in Leeds.
CBRNE materials, or their precursors, are used throughout a modern industrial economy. Subway attackers in Japan home-brewed sarin gas. The Oklahoma bombers mixed fertilizer and fuel oil; the London gang probably worked with acetone, hydrogen peroxide and acid--all available in the U.S. at pharmacies or hardware stores. Seriously dangerous radioactive materials are widely used in hospitals and in many industrial applications. I've heard a credible account of how a powerful nuclear source stolen from an industrial factory came close to shutting down a city. The U.S. CBRNE attack, when it comes, will most probably involve materials stolen from a legitimate U.S. user or concocted in a one-bedroom New York apartment from ingredients that are cheap, legal and widely available.
So we know exactly what we need to defend ourselves--sensors as cheap, easy and (in the end) commonplace as the targets they sniff. The sensors have to be good enough, when scattered all around, to pick up tiny traces wafting from an open window or through the seams of one backpack passing through the crowded entrance to a subway. At the same time, they have to be extremely discriminating and accurate. Security people won't buy the cheap CBRNE sensors currently available because they sound too many false alarms, and every alarm empties the building or shuts down the station.
Happily, both government and the private sector have been pouring money into the development of sensors, and the investment has paid off. Chip-scale and pager-size CBRNE sensors as good as a dog's nose, or better, now exist. So do semiconductor crystals surrounded by the right microprocessors and sophisticated software, able to pick up the telltale emissions of the most worrisome radiological materials. Recently developed semiconductors emit ultraviolet light at just the right wavelength required to fluoresce the proteins that surround certain biological toxins. Enzymes and other chemicals have been engineered to respond very precisely to almost unimaginably tiny concentrations of a growing catalog of explosives, nerve and blister agents, and other threats. Microscopic tuning forks built on silicon chips change tone in known ways when tiny traces of target molecules land on their surface. Precisely tuned lasers excite airborne contaminants at a distance, with optical sensors picking up the signature glow on the return.
Video cameras protect us only against yesterday's threats--threats the size of people, or larger. So they give us a snapshot to examine after the face has been blown up with the backpack. Sniffers scope what's inside the backpack. Yes, in theory terrorists can keep their toxic kitchens fantastically clean and seal up their poisons so tight they don't reek or radiate at all. But smells are very much harder to hide than faces and much easier to read. They persist for days, they creep through tiny cracks, and they drift as freely as air from private spaces into public ones. Forget about olfactory privacy. The only defense we have against poisons that can be brewed and hidden by anyone, anywhere is to sniff everyone and everything, everywhere.
I invest in private companies that are developing some of these technologies, and no doubt that clouds my judgment. But unless you put all your faith in winning hearts and minds worldwide, there's no alternative. Brilliant techies have to perfect the sniffers, which we then have to deploy everywhere, to find the acetone, anthrax and thermal neutrons--before they find us.
Original Source: http://www.forbes.com/free_forbes/2005/0815/098.html