Can heat really be this bad?

Hi ladies need opinions.im hispanic nd have wavy hair.havenr used heat on my hair for.years no heat at all i air dry my hair nd do heatless hairstyles but at times i get tempted to use styling tools but end up not using them.started seein this on the news.i know its more is straightnin chemical products but they also are sayin flat irons, curlers hair dryers contain chemicals in them that cause cancer too?? My 14 year old haa been buggin for stylin tools but i worry.what is ur opinion on this? Think ima just stay on my natural.journey