Reburn, in which a secondary fuel stream is injected into a combustion system after the initial Combustion is virtually complete, is a potentially useful retrofit technology for the control of NOx in industrial furnaces. Orimulsion, a bitumen-in-water emulsion, is considered to be a prospective reburn fuel both economically and technically. A series of combustion tests have been carried out in PowerGen＇s 1 MW Combustion Test Facility, to assess the potential of Orimulsion reburn in a coal-fired system fitted with a low-NOx burner. With Orimulsion used to supply approximately 20% of the thermal input to the system, NOx emissions could be reduced by approximately 40% while simultaneously improving combustion efficiency. Heat-release patterns within the combustion chamber were not significantly altered during reburn testing. On the basis of these tests, Orimulsion is concluded to be a potentially attractive reburn fuel.