If your hair straightener is giving off a bad smell, it could be due to a number of reasons. First, if you're using an older model straightener, the heating element could be worn out. This can cause the element to overheat and produce a burning smell. Additionally, if you haven't cleaned your straightener in awhile, it could be full of built-up hair products and residue, which can also lead to a burning smell when heated. Finally, if you're using a ceramic or tourmaline plate hair straightener, it's normal for these materials to give off a slight wet or ozone smell when they get hot. If this is the case, simply open up a window or door to air out the room while you're using yourstraightener.