The report gives results of a Source Test and Evaluation (STE) of the lignite-fueled Riley Gas Producer as part of EPA's program to define and evaluate the environmental effects of low-Btu gasification. (NOTE: In December 1979, the Gas Producer, fueled by North Dakota (Indianhead) lignite, was tested at Riley Stoker Corp.'s research center in Worcester, MA, sponsored jointly by Riley Stoker and American Natural Service Co. of Detroit, MI.) The STE involved characterization of all inputs and outputs of the Gas Producer. Material balances were also developed. The output streams included the product gas, ash pan water, cyclone dust and gasifier ash. The results indicate that all output streams have some potential for environmental concern, as either fugitive emissions (product gas) or discharge streams (dust, ash, ash pan water). Analyses of the leachates of the gasifier ash and cyclone dust showed that they were nonhazardous according to Resource Conservation and Recovery Act (RCRA) protocol and standards.