When you burn antifreeze, it produces a number of toxic chemicals. The most notable of these is ethylene glycol, which can cause serious health problems if inhaled or ingested. Inhaling even a small amount of ethylene glycol can lead to headaches, dizziness and nausea, while larger amounts can cause kidney damage and even death. Burning antifreeze also releases other harmful chemicals into the air, including carbon monoxide and oxides of nitrogen. These can both cause respiratory problems and exacerbation of existing medical conditions such as asthma.