Any Proof of Chemtrails?

Has there been any scientific studies on chemtrails? Any analysis of suspected chemtrails? Anything at all other than a bunch of mopes pointing to a contrail and screaming "Chemtrail!! They're trying to kill us all!"

I've watched several YouTube videos on chemtrails and that's all they ever amount to. When asked for evidence, people always just direct you to a nutjob website where there's a lot of excited talk about how chemtrails are "real" along with photos of contrails as "evidence." Never any real science going on, just faulty assumptions based on eyewitness accounts of contrails.

So, has there been ANY real scientific investigation into this subject or is it heresy even to ask?