Bug Spray Truck

I remember as a kid running behind the bug spray truck on my bike. We played a game where we would see who could ride behind it the longest without bailing. For "protection" we'd pull our shirts up to our nose as a very ineffective mask that did nothing.

Who knows what they put in those things back in the 80's and if my Mom ever knew about back in the day we would have been in trouble but these days when I see the truck go by and the weak (I'm sure improved) spray that evaporates immediately, I think about riding my bike through a big billowing cloud of smoke and smile.....then cough up more blood.

What did they put in those clouds back in the day?