Chemtrails? Why We Don't Know

I will admit that if you study the contrails closely, you can find evidence of DHMO (Dihydrogen Monoxide, also known as Dihydrogen Oxide or Hydric Acid), a substance that will kill you if you inhale very much of it.

http://www.dhmo.org/facts.html

But that's definitely what's in... um... chemtrails.