Is it safe to breathe fumes from a melted carbon filter?

So I read online that if you put an activated carbon filter in the oven for a little bit it can reactivate the carbon. I did that and went to the store and when I came back like 20 minutes later huge amounts of steam was coming out of the oven and the whole house is filled with the smell of sharpie. I opened the oven and the carbon filter was completely burned to a crisp, crumbling into dust at any touch. Wtfh? I don't understand why this happened, but my question is whether these fumes are toxic because the house is full of it...