Crack is cocaine that isnt bound to a salt (HCl) so that it burns at a lower temperature and is more effecient for smoking. Its still cocaine, which is cardiotoxic, the only difference in smoking is that it gets to your blood quicker producing stronger but short-lived effects.
Baking soda isn't necessary in freebasing, you could also use ammonia for the process which would require no heat. Sodium bicarbonate (baking soda) when burned emits carbon dioxide.