Well I'm not sure just how banned it might be but I can still buy thermostats for my furnace that use a mercury switch. I have three mercury switches that I keep wrapped up and inside film bottles till I use them. I have kids and I don't want them breaking them open. I remember playing with this stuff in grade 3.. times have changed.. Anyways once I have them mounted I'm encapsulated them in some sort of plastic/silicone with a note that there is mercury inside.. the stuff ain't great for the environment. Some don't care but I still would want someone to know its there.