Petroleum-based (paraffin) candles are toxic. When burned they release carcinogenic toxins such as benzene, toluene, formaldehyde, acetaldehyde, acrolein and soot into the air. Besides cancer, they have also been found to be linked to birth defects and respiratory ailments such as asthma. The emissions from paraffin candles contain many of the same toxins produced by burning diesel fuel. It is like starting up a diesel engine inside your home! Unfortunately, the FDA doesn’t require candle makers to list the ingredients in candles nor do they require them to list any warning of potential side effects. Hence, you never really know what you’re burning.