Scented candles can cause migraines, eye problems and increase the risk of respiratory problems. Most candles are manufactured Paraffin wax, which is a byproduct of the oil refining chain.
When certain candles burn, they release toluene and benzene into the air, both of which are known carcinogens. In addition, there are candles that contain wicks where the cotton is wrapped around another material such as metal and produce toxic soot, which may cause damage to the lungs.