(US5430207-A)      Recovery comprises: a) charging complex hydrocarbons to a reactor, b) heating the complex hydrocarbons to 95-260 deg.C in an O2-free environment; c) irradiating the complex hydrocarbons with radiation of wavelength 1-400 nm and intensity of 50-450 MJ/cm2 to excite and break chemical bonds between atoms to produce simpler hydrocarbons; and d) recovering the simpler hydrocarbons produced. Irradiation in step (c) is carried out for sufficient time to vaporise a part of the complex hydrocarbons.    Steps (b) and (c) are carried out in a reaction under 100-400 mm Hg pressure. Complex hydrocarbons are organic polymeric compsns., esp. associated with oil shale or tar sands.    USE/ADVANTAGE -   Recovery of simpler hydrocarbons for fuel. Less pollution of environment.    (JP8510774-W)      Simpler hydrocarbons (I) are obtained from complex hydrocarbons (II) by (a) charging (II) to a reactor; (b) heating (II) to 95-260C or to a temp. approaching the softening point of (II) in a substantially oxygen-free environment; (c) irradiating (II) with radiation of wave length 1-400 nm and intensity 50-450 MJ/cm2 to excite and break chemical bonds and produce (I); irradiation is carried out for sufficient time to vaporise a substantial proportion of (II); and (d) recovering (I).    USE -   (II) is esp. waste plastics (organic polymers); it may be oil shale or tar sand material. Product (I) is suitable for use as a fuel.    (EP699175-B1)      Simpler hydrocarbons (I) are obtained from complex hydrocarbons (II) by (a) charging (II) to a reactor; (b) heating (II) to 95-260C or to a temp. approaching the softening point of (II) in a substantially oxygen-free environment; (c) irradiating (II) with radiation of wave length 1-400 nm and intensity 50-450 MJ/cm2 to excite and break chemical bonds and produce (I); irradiation is carried out for sufficient time to vaporise a substantial proportion of (II); and (d) recovering (I).    USE -   (II) is esp. waste plastics (organic polymers); it may be oil shale or tar sand material. Product (I) is suitable for use as a fuel.