A burner for firing of grain was investigated for function, safety and emissions. Fuel, ash, particulates, gas and condensed flue gas from the inner surface of the chimney were analysed, and the stainless steel chimney were analysed with SEM/EDX. Three security systems should give a high safety against back-firing, provided the sensors are correctly placed and in function. Frequent cleaning of the boiler/burner was needed and some sintering noted. Emissions of CO and OGC were low, but of par-ticulates, NOx, SO2 and HCl higher compared with pellet. The condensed moisture was very sour and had high content of chlorine. After 800 cycles, the chimney was ruined by corrosion. Establishing of a list of near-accidents and fires in cooperation with insurance companies and an inventory and closer study of suitable materials for chimneys is recommended. If grain firing expands, techniques for re-duction of particulates, nitrogen oxides and acidifying substances should be developed.