Seems someone else disagrees..........a Federal agency.....
http://cameochemicals.noaa.gov/chemical/14053
From what I've read, I make it out to be a case of friction of the components - their being impacted with a certain force and/or frequency that could raise internal temperatures enough to ignite it.......or at least something like that.....
That would explain being able to handle it in small quantities, or mixing it, in most cases, without mishap.