Disadvantages
Deep frying produces large amounts of waste oil, which must be properly disposed. Waste oil is increasingly being recycled into biodiesel.
Cooking oil is flammable, and fires may be caused by it igniting at too high a temperature. Further, attempts to extinguish an oil fire with water cause an extremely dangerous condition, a boilover, as it causes the water to flash into steam due to the high heat of the oil, in turn sending the burning oil in all directions and thus aggravating the fire. This is the leading cause of house fires in the United Kingdom. Instead, oil fires must be extinguished via fire extinguisher or by smothering. Other means of extinguishing an oil fire include application of dry powder (e.g., baking soda, salt) or fire fighting foam. Most commercial deep fryers are equipped with automatic fire suppression systems using foam.
Read more about this topic: Deep Frying