I'd expect emergency gas masks to be carried by all adults and children aka WW2 in towns and villages near such facilities.
Wouldn't help. Any lithium battery fire creates hydroflouric acid (not to be confused with hydroclouric) acid which is absorbed on skin contact, at which point it breaks down and somehow has a nasty chain reaction that sinks into your skin down to the bone and starts killing the flesh and bone. Exposure to air with the stuff at a concentration of 50 parts per million for 5 minutes is apparently a lethal dose, and i'm not sure that anybody actually carries instruments capable of detecting the stuff.
If you know when your affected then you can get treated, but pain only sets in something like 12-24 hours after contact at which point the pain is in response to the final stages. Apparently if you had an arm affected then they'd have to amputate it to avoid the effect spreading. If you breathed it in? The suggestion that I heard was make a will, and say your goodbyes to your loved ones.
HF really freaks out chemists and people who know what it does. I know it freaks them out, and I know that the Material Safety Data Sheets all require full self contained breathing apparatus and full hazmat style bodysuits to prevent any contact with the stuff and is probably best avoided.