Are chemicals in self-cleaning litterboxes bad for cats?

Question
I wanted to get my beloved cat a self-cleaning litter box but I'm afraid the chemicals in the crystals that dissolve the odor/urine might not be healthy for him. Would it shorten his life or something if he inhaled the fumes?

Answer
I can't really answer this as I would never use one of them. I wouldn't think that they are made to be harmful, but why would you subject your cat to chemicals if it isn't necessary?

My personal answer would be don't use them but it's a personal choice.