Good question. What happens? You must have missed my earlier post (and your 8th grade science class) about the scientific principles of evaporation.
Dissolved solids do not evaporate. This is why rain water is fresh water, not salt water. Simply stated, evaporation is nature's purification process. The water molecules evaporate, leaving the water's adulterants behind.
Of course, you're probably thinking to yourself, "What about acid rain?" Fair question. Acid rain is not acidic because of chemicals that have evaporated from bodies of water. Acid rain is acidic because of gases and particulates that are ejected into the atmosphere from the burning of fossil fuels, primarily coal. These particulates then are captured in clouds by water droplets formed by water molecules clinging together. The water droplets, mixed with the acidic particulates grow too heavy to be suspended by wind and eventually fall to the ground. But is has NOTHING to do with evaporation.
And yet, both the dispersant and the oil are liquids.
But what they are dissolved IN, does EVAPORATE.
Don't tell me you don't understand that 'process'.
Now, which of the chemicals in COREXIT is a solid?
And would you guarantee that the large amount of petroleum, and the methane GAS that is escaping the well, along with the dispersant as it breaks down, cannot evaporate into the atmosphere and 'come down with the rain' like the gases you mention?
I'm not asking you to judge whether they are what is causing this crop damage, but whether the chemicals (as gases) from the sources mentioned could evaporate and come back down with the rain.