This residue contains a few percent by weight of phenol and isomeric cresols. These residue contains a few percent by weight of phenol and isomeric cresols. About half of the world's supply of cresols are extracted from coal tar. In place of phenol itself, they are often produced from cresols (methylphenols). Short-term and long-term studies with animals have shown similar effects from exposure to cresols. It contains proteins, lipids (notably cholesterol), phenols, cresols and sesquiterpenes (notably farnesol and its derivatives). Ring hydroxylation to cresols is a minor pathway in the metabolism of toluene. No human or animal studies have shown harmful effects from cresols on reproduction. This emulsion contains, dissolved in small particles, the active material, whether phenols or cresols. The original formulation of Lysol contained cresols. Cresols (also "hydroxytoluene") are organic compounds which are methylphenols.