Can bio-oil used in hotels be poisoned?

If refined methanol is used to prepare bio-oil, carbon dioxide and water vapor are generally burned, which is basically harmless, but if it is prepared with crude alcohol or waste alcohol, it is very harmful to human body. However, there is no guarantee that other substances will be added to food besides bio-oil, so it cannot be generalized. Bio-oil is a potential liquid fuel and chemical raw material, which has the characteristics of wide source of raw materials, renewable, convenient transportation and high energy density.