Help with terra cotta

My question is this:

Are terra cotta pots, planters, lids, bases from your local hardware store (Ace Hardware for me) lead free? Or should I worry about using said items (ie smoker made of terra cotta planters, pizza stone via a planter lid/base)
I’ve made one of the smokers that Alton Brown demonstrated. Since it doesn’t make contact with the food in any way, I can’t see where there could be an issue. The pizza stone idea would be a different story, though I doubt Alton would steer us wrong. If you’re still concerned, I think you would need to contact the terra-cotta manufacturer to find out more.

Alton also use a huge terra cotta pot in his roast episode, but he cooked the roast in a 13×9 pyrex dish, so there was no contact.

FWIW, people use terra cotta pots in some fish tanks to breed some types of cichlids.
so is that a "its ok to use the terra cotta lid as a pizza stone"?