This was posted at Alien Earth forum and there was no news story with it. I Googled it, using all the related keywords I could think of, but came up with nothing. So I have no idea where this happened. Sorry. If you find out where it happened, please leave a comment here with a link. Thanks.
As soon as I saw that cloud start to roll in, I was immediately reminded of that Stephen King movie I watched last week called "The Mist." But this cloud, even though it is toxic, isn't quite as scary as the one in the movie...at least there aren't any monsters in it, (well...besides anhydrous ammonia).