The terrorist bombings in Brussels on Tuesday that killed more than 30 people were a reminder of more than just the vulnerability of urban infrastructure to dedicated individuals with explosives. They also pointed out that different kinds of infrastructure come with different kinds of dangers.
Case in point: an enclosed space like a subway station can magnify the effects of an explosive. Blast injuries like the ones people suffered in Brussels’ Maelbeek subway station are much worse than those incurred in open air. It’s a matter of physics and physiology.
After two decades of attacks in subways in London, Paris, Madrid, and Israel, the somewhat gruesome field of inquiry into blast injuries in enclosed spaces has yielded some changes. Station platforms have fewer trash cans and more open space now, and less glass at ground level. That means less stuff to turn into projectiles. But underground rail stations are still one of the most difficult types of spaces to protect and make safer.
That’s because of how explosions work. “The initial kinetic energy generated by the blast is a gigantic pressure wave, like a sonic boom,” says David Lemonick, a retired Pittsburgh emergency room physician who wrote a blast injuries primer for ER docs. “There’s an initial overpressurization that blows out your eardrums and your lungs, knocks you down, sends you flying, and then picks up other stuff in its wake and shoots it all out in different directions.” […]