A study has been initiated to determine the extent to which molten carbonate fuel cells (MCFCs) can withstand in-situ soot precipitation or small quantities of foreign particles depositing in the cell as a result of the use of coal-derived feed gases (e.g. amorphous and graphitic carbon formation, fly ash, tar particulates, etc.). Also, the effects that low level 'gaseous'contaminants deriving from coal gas can have on the cell are to be studied (e.g. As, NH/sub 3/, high molecular weight and cyclic hydrocarbons, zinc and various trace metals). Both out-to-cell, mostly TGA experiments, and in-cell testing are being performed to confirm or deny any suspected deleterious effects on the active matrix and electrode components or on the overall operability of the system. The parameters of cell performance that are constantly monitored are current/voltage functions, cell resistance, back pressure or leakage, and fuel/oxidant utilization in the cell. Particulate additions to a bench-scale fuel cell are currently under way. Different types of dust and different particle sizes are being generated and injected in the fuel gas stream to determine the capacity of the fuel cell to ingest various quantities of foreign particles. 15 refs., 28 figs., 13 tabs.