The development of laboratory instrumentation systems for investigating the gas-phase thermal decomposition behavior of organic materials has evolved over the past ten years. In these systems, high-temperature tubular reactors are used for the controlled thermal exposure of different gas-phase substances. Gas chromatography has been the major analytical technique for determining the extent of thermal decomposition and the formation of various products of incomplete combustion. The evolutionary development of laboratory instrumentation covering seven thermal systems is summarized. Examples are presented of the application of laboratory studies to the controlled high-temperature incineration of industrial organic wastes.