[Kallikrates]

In another life I had to take aircraft crash response training, and was in charge of recovery (salvage, battle-field repair etc). The response to an aircraft with composite materials is totally different. With normal construction we could get to work as soon as the fire, was out and any hazardous liquids were taken care of. Crashes involving damage to composite structures required that the damaged areas be sprayed down with a varnish like chemical by the same troops who handle Chemical weapon response (they had special suits). Then there would be air particulate tests before we could move in. Here is a military study: http://www.dtic.mil/dtic/tr/fulltext/u2/a420193.pdf

[splawn]

A long time ago a coworker told me about this. He told me it was because the dust was conductive and would wreck havoc with electronics.

[JabavuAdams]

I've heard an anecdote along these lines, too. It was about a lathe that had been exposed to carbon-fiber dust starting to turn when supposedly off.

[JabavuAdams]

There's all kinds of nasty stuff in and around aerospace / military wrecks. It always boggles my mind when I see kids playing on wrecked equipment. DU aerosols, hydrazine, CF aerosols, and who knows what else.