“…In addition to saturated hydrocarbons, nonaromatic olefins, and oxygen-and nitrogen-containing "hetero" compounds, these cracked gas oils have been variously found to contain alkyl benzenes (4. 5,8,20), styrenes (9), naphthalenes (8-5, 8, 20), fluorenes (2) phenanthrenes (2-5, 7, 8), anthracenes (2, 4, 5, 7, 8), and pyrenes (3,4,7).…”