The level of oxides of nitrogen (NOx) emissions from municipal solid-waste incinerators in the UK is currently limited to 350 mg m(-3) but proposed European legislation will reduce this figure to 200 mg m(-3). The Coventry incinerator NOx levels were in the region of 450 mg m(-3) and a flue-gas recirculation system was installed to reduce these emissions. The system was tested over a three-month period and was found to reduce the NOx levels by 30-37% allowing the plant to meet the current standards. There were a few occasions when levels were above 350 mg m(-3), but the frequency of these could be reduced through improved mixing of the waste before combustion. Flue-gas recirculation has now been adopted on a permanent basis.