It might surprise you to know that paraffin is basically the grayish left over sludge produced by petroleum refineries. This paraffin residue is bleached with toxic chemicals and then used to mass produce your average candle. Paraffin waxes contain aromatic compounds which are released when a candle is burned. These compounds have been proven to be carcinogenic. As paraffin wax burns it creates a black soot that coats your walls ceilings and lungs. This petro-soot is as harmful as second-hand tobacco smoke.Many paraffin candles are made with wicks that contain lead or zinc, which, when burned pose yet another health hazard. Some paraffin candles emit such hazardous pollutants as acetone, benzene and lead. These harmful substances impair the quality of indoor air. Beeswax candles burn cleaner and drips less than those made with paraffin wax (the fumes of which have also caused kidney and bladder tumors in laboratory animals). If you have noticed sooty deposits in your house, paraffin wax candles may be at fault.