I too have heard and read the articles about clumping litter. But further research has shown me, that is in indeed safe to use. There are articles peppered all over the Internet about the pros and cons of it, so it is just best to do all the research and then decide.
If you have baby kittens and you are using clumping litter and they have not yet mastered the litter pan manners, simply clipping the long hair off their rumps will stop any litter from forming there.
When I rescued a declawed kitty, I stopped using clumping litter as it hurt her paws to use it. But just read the research and decide for yourself if you want to use it or not.
Here is an informative webpage on it:lisaviolet-clumping litter