Long ago, when our grandparents were younger, scientists knew far less about chemicals and drugs. Stores sold all kinds of products that seemed safe and sometimes useful. As research was done, it turned out that many of these products were dangerous to our health or the environment. So the governments banned them, regulated their use, or removed them from shelves. Here are 10 products that used to be legal, why they were used, what we learned about them, and how the laws changed.