who is to say that the baloon did not already leak out chemicals throughout the US? you know, drizzle a bit here, and a bit there? Over the main bread basket?
My wife mentioned this to me. I didn’t argue with her, but I wonder what might be something that would do much damage released from that high of an altitude. It would be so dispersed by the time it hit ground.
Radiation? I imagine much more was released from a single test in Nevada in the 50’s than could be carried in a ballon.
A virus? It would be not viable by the time it hit ground.
I suppose there are things, perhaps, but it seems unlikely.