Naturally, it is dangerous for Criss Angel to perform his style of illusions. He is taking a significant risk by performing them. In the future, he should be more careful in order to protect his own safety and perhaps the safety of his audience as well. Safety should come first.
Without knowing the background of how most of his illusions are really performed, I can't truly say. But it certainly seems that Criss Angel could get hurt or killed during some of his performances. Being near explosions, climbing up buildings, being buried alive, and lying on broken glass aren't exactly safe even under controlled conditions.
Some of the illusions he performs probably are pretty dangerous, however it is his body and he can do with it what he wants. The most dangerous one that I saw was where he swallowed gasoline and then spit it back up to light it on fire. It's dangerous, but his decision.
It is not dangerous for Criss Angel to perform his illusions. He knows what he is doing and he understands the risks. I think that as long as he does not harm anyone else during one of his illusions then he should be allowed to do them. This is his career.
No, it is not dangerous for Criss Angel to perform his illusions, because most of the time, his illusions are not something where someone could easily get hurt. He is not likely to get hurt levitating, or even walking on water. He also has safeguards in place to make sure that safety is observed during his stunts.