Over the years I have lived, the plates used in batteries have change in content, and cadmium was unheard of back when I was younger, and fooling around with stuff for a cheap source of lead. I am well aware of the toxicity of cadmium. I also have an idea of how little actually is in those batteries. I understand that zinc is now being used in batteries, and that element combines with cadmium very well.
As to whether people exercise common sense, everyone is entitled to their opinion. IMHO, this country has spent much of the last two generations doubting everyone about everything. I don't happen to think that is either healthy, politically, or necessary. It has allowed us all to doubt the wisdom of the founding fathers of our country, the strength of democracy as a political system, and the value of Individual Freedoms, in favor of a steady erosion of those rights( and the responsibilities that go with them). Instead of demanding government to assist in training and education of our citizens to deal with issues that were routinely taught by parents at home, we have meekly allowed our Representatives to tell us we " can't Be Trusted" to use common sense, or even have it, and that laws need to be passed restricting our freedoms to protect us from ourselves. Our government has not won many points for its ability to teach much of anything, but at least some schools teach our young basics skills. There is no better performance level in any other activity that we allow our government to do for us.
I said I don't mess with batteries any more, but I have met people who say they do. They seem to know the dangers, and are willing to accept those risks. That is their right as a Free People, INMO.
As for the Carcinogen scare tactics, my Gosh, fellow, there are carcinogens in the resins in Pine logs you use to burn in your fireplace to provide a nice scent to your home at X-mas. There are carcinogens in the fat that is grilled, or baked in your oven. If you are going to let the existence or absense of carcinogens control your daily existence, you might as well pull the sod over you right now.