Furthermore, three classes of toxin constituents were established: the first class includes lowtoxicity compounds that do not require special investigations, at the 'fifth percentile no observed effect level'(NOEL) of 3.0 mg/kg per day; the second class includes components less harmless than first class, which do not raise major toxicity suspicions, at the fifth percentile NOEL of 0.91 mg/kg per day; and finally the third class contains components of significant toxicity, which decreases the safety of the EO, at the fifth percentile NOEL of 0.15 mg/kg per day. Unidentified components are also categorized under the third class