I just happen to have a conversation with Matt Ocko, a venture capitalist, about this on Twitter tonight:

https://twitter.com/mattocko/status/712227775805988864

TATP (acetone peroxide), the type of improvised explosive favored by terrorists because of the easy access to ingredients, is uniquely difficult to detect but there have been some recent advances in this area [0]

Most of these attackers use vests that carry 2-10kg of TATP, or backpacks with 10+ kilograms. They are required to load these devices up and travel to their designated target, the hope is that with explosive detection you could pick these guys up or minimize casualties in the same way you could identify a gunman on CCTV.

It wouldn't be a panacea - but it could form part of a broader set of new tech to assist with these cases

[0] http://www.sciencedirect.com/science/article/pii/S0925400511...

Many commonplace chemicals, such as hand sanitizer, confound the explosives detectors used at airports. Dogs can only work a very limited time before their sense of smell gets fatigued.

Moreover, the bomb was set off outside the secure area. It is VERY likely that existing security measures got more people killed because there are dense crowds waiting to clear security. This exact type of attack, outside the secure area, was predicted long ago. And there you have it.

Without better information on the whereabouts of the explosion, it's hard to draw any conclusions. But from the photos I've seen, any crowds targeted by the bomber(s) would not have been due to security lines, but rather the densely packed lines at the various airline checkin desks. Unlike most American airports, where broad desks face the outer wall, at Zaventem they're arranged in facing rows like booths at a convention.

Any security lines are actually past passport control, and I've never seen them particularly packed.

So perhaps the security lines need to be outside the check-in area? See what I did there?

According to BBC the explosion are believed to have been in the checkin area, i.e. outside of the security screening.

This is a clear weakness of airports: where people regroup even before reaching the terminal, with no surveillance or security checks whatsoever. And that's not just in Brussels.

But why should checkin areas be more protected than any bakery, bus stop or supermarket, any place where people gather. One can't (and shouldn't) put policemen at every corner of every street.

And of course not just in airports. Train stations, buses, markets, theatres, concerts (Balaclan), anything you have in city life where people gather together.

Metros and mass transit are generally the most lucrative target, as we see here, and as we saw in London 10 years ago.

Only place I've seen some security checks was at Ben Gurion airport in Tel Aviv, where there was a mild security check when entering the airport.

This consisted of a small interview on what I've been doing in Israel, where I am going to, with whom and who packed my stuff. This all was before even entering the actual terminal building.

I see Europe in the future adopting many of the (some call paranoid) security measure of Israel. For example security checks before entering all malls.

In Paris, there are security checks at entrances to malls and big stores now.

Yeah I don't think this is easily mitigated short of increasing throughput through check in / security so that you never have large groups of people standing around.

I traveled through Baku airport in Azerbaijan last summer which had body and luggage scanners at the entrance to the terminal. I wonder how long before this becomes the norm?

This really won't help the issue. You still create choke points where many people are waiting to pass through the security check.

People interested in killing others will just go for the easiest place, so they will just bomb the line at the scanners entering the terminal.

I talk to a lot of frequent fliers, and almost every one of them has said that there is no point to a terrorist trying to bomb a plane any more. The easiest target for terrorism is simply the insecure portion of an airport. We saw this today in Brussels.

Get dogs trained to detect explosives patrolling all areas of the airport and I'm not sure what they're called, but they have these sniffer devices at the CN tower where they basically make you walk through a large hairdryer and it sniffs the residue blown off you for chemical signatures. It's not perfect, but a combination of those two things any place where you have large volumes of people congregating would surely yield an above average result. The dogs alone I would wager would be an efficient response - they're portable, don't take up much room and can clamber over all kinds of obstacles.

A malicious person will always be able to find a public space with lots of people. A public square, schoolyard, mall, busy street, library or whatever.

Besides, to defend against suicide bombings, the dogs would have to encounter everyone before they enter the airport checkin area, otherwise the bomber could just detonate once the dog start barking (or whatever they do to mark that they've found something).

Perhaps, but then bombs could just be detonated in open public squares, playgrounds, etc - it's actually surprising they're not.

Indeed, you cannot protect any place when more than a few people gather.

You have to stop the issues at their source: why did people who were born and raised in Europe radicalize in just one or two years? And why did the community they lived in not see or report that this was happening?

While I agree, I think we can admit that doing so will take some time. Would it not be appropriate to have compensating controls in the meantime?

The trouble is, temporary compensating controls have a history of becoming permanent once in place, so you need to be absolutely sure you want those controls forever.

That's a good point, and while I hesitate to think about this terms of pure risk management, the same stuff happens in my company.

Indeed, the explosions were in the checkin area. I was there last week and there's a couple of armed soldiers in the area, but you can walk right in without any security screening.

Explosives detection is a perfectly worthy thing to do.

Unfortunately, by the time there's a bomb at the airport, it is too late unless "James Bond" is on the scene.

The core issues here need to be addressed.

why is it too late? it can still save many lives even if there is a 5 min notice

It is "too late" if you want to actually solve the problem of terrorist organizations blowing up people at airports.

Yes, we should have security and even bomb detection tech in select public places... but that's secondary to what needs to be done to fix this mess.

They don't scan for explosives until you're going through security. If they had the security checkpoint at the entrance to the airport:

a) People would bitch more because it would take forever to get into an airport. And,

b) It isn't practical. What's next, stopping you at your car or bus before you park?

People demand security but don't want inconvenience. And if security fails, they point and say "it's ineffective." Even if it stops 80% of attacks, unless it's 100% people will bitch. AND if there aren't any attacks, can they really claim that they stopped one unless they publicly acknowledge every attempted attack?

It gets worse, since in this case it's not even a trade-off between convenience and security. In Sri Lanka they had (and perhaps still have) security scanning at the entrance to the terminal.

As a result people have to bunch up outside the terminal, making them even more vulnerable than they otherwise would be.

Any true improvements would have to come from streamlined pre-screening, e.g. chemical detectors (or dogs?) in the concourse sniffing things out without making people stop or bunch up. Hard to do.