Absorption oils, bicyclo arom. and heterocyclic hydrocarbon fraction; Wash Oil Redistillate; [A complex combination of hydrocarbons obtained as a redistillate from the distillation of wash oil. It consists predominantly of 2-ringed aromatic and heterocyclic hydrocarbons boiling in the range of approximately 260 °C to 290 °C (500 °F to 554 °F).]