Chemical is warfare is illegal, but they used gas masks, mostly air filters to get clean air to their lungs.
One of them would be that he warned them of the young republic. I don´t know the other one. <span />
The main reason why there was a massive immigration towards the Sun Belt was because it was unoccupied relatively to the other areas of the US, this meant that new servrices and industries could be developed for the young and flourishing naiton.