Use essential oils in safe amounts, toxicologist says By Jake Chung / Staff writer The use of essential oils to induce relaxation has become increasingly popular, but toxicologist Chao Ming-wei (招名威) suggested using diffusers that distribute measured doses, saying that the key to using essential oils safely is the amount to which people are exposed. Essential oil manufacturers could add fixing agents, essences, surfactants and ethanol-based products to essential oils, and exposure to excessive quantities of such products could damage a person’s lungs, liver and kidneys, Chao wrote on Facebook last week. It is documented that the use of essential oil dispensers indoors increases the levels of carbon monoxide and carbon dioxide, as well as the amount of particulate matter inhaled, he said.