There is actually a major difference between a CONTRAIL and a CHEMTRAIL. I know you have a problem conceding that ad for some reason - you dont want to admit it - but there is. A contrail is ICE and doesn't last very long because its rapidly converted back to water vapour. Chemtrails are manufactured mixtures (not compounds) composed of aluminium metal, aluminium oxide, barium sulphate, strontium chloride and additives to allow the heavier barium sulphate to ballast the other particles to keep them from blowing (too quickly) away This formulation isnt an accident, the main aspect is the high reflectivity and high 'whiteness' coupled with persistence arising from greater inertia, since at these altitudes (35,000+') the buoyancy is assured and the main concern is inertial retardation (ie staying in pace to enable the trail to be built up in consecutive layers). It has nothing to do with aluminium toxicity. The accusations against Monsanto on this particular case are bullshit - but that doesn't mean Monsanto aren't a bunch of crooks - it just means the guys trying to fight them aren't all that bright and cant afford good chemical engineers.