Nootkatone, a chemical found in cedar trees and grapefruits, was recently approved by the US EPA for use in repelling ticks, mosquitos and other potentially dangerous insects.   According to the EPA, Nootkatone is considered nontoxic to humans and other mammals, birds, fish and bees. The oil is already used in the food and fragrance industries.   According to The New York Times, one proposed use is in soaps that people in tick-infested areas could shower with, repelling and possibly killing tick...