I was just flagged by the air-puff machine at BOS as having explosive type E-8 on me. I noticed on the sheet the guy wrote me down on that everyone else was E-3, with the exception of one person who was both E-1 and E-3.

Everything went smoothly with the pat-down and bag search/swab tests afterwards, so it wasn't a big deal. But I'm curious what E-8 is (and the others I saw.) I haven't been around any explosives, firearms, farms, fields, or anything of the sort anytime recently. What's the false alarm rate on these things anyways?