Research on the effects of heating oils has been geared toward understanding safe practices for deep-frying and industrial purposes. In a study published in 2010 by the “Food Chemistry” journal, researchers studied the emissions from four commonly used oils — safflower, canola, extra virgin olive and coconut. Each was heated to four temperature levels, and its emissions were analyzed for certain toxic fumes, including aldehydes, which are known to be cancer-causing. When an oil exceeded its smoke point, the amount of toxic fumes increased significantly, according to the study. Canola oil, with the highest smoke point, gave off the lowest levels of toxic fumes. Coconut oil, which has the lowest smoke point of the four studied, emitted the greatest amount of total volatile fumes at all but the lowest temperature.