and another one

Thanks for all the responses about gov't agencies. In return, I give you more questions!

Small, wealthy New England town. Residents start freaking out inexplicably, causing car accidents, enacting violence against each other. What's the protocol, in terms of declaring and enforcing a state of emergency? Does the mayor direct activity? How is the emergency broadcasting service put into effect? What would be the chain of command, to get word to the police and press not to go near the site?

I don't need this to be perfect, but I do want it to have verisimilitude.