The operation of solid oxide fuel cells (SOFC) was evaluated on simulated coal gas in the presence of several coal gas impurities that are expected to remain in low concentration after warm gas cleanup. Phosphorus, arsenic and sulfur were considered in this study. The presence of phosphorus and arsenic in low, 1 -2 ppm, concentrations led to the slow and irreversible SOFC degradation due to the formation of the secondary phases with nickel in the upper part of the nickel-based anode close to the gas inlet. Sulfur interactions with the nickel were limited to the surface only. Cell performance losses due to sulfur exposure were reversible and independent of the presence of other impurities.