Executive Summary: This project investigated the combustion performance of blends of unrefined Jatropha oil and its blends in laboratory boilers. Although a very limited amount of testing blends in distillate oil, ASTM No. 2 oil or heating oil was conducted, the primary interest was in testing the performance of blends with residual ASTM No. 6 oil. The basic idea is to provide a renewable fuel option to residual oil used in space heating and in industrial applications. The intent also was to explore the use of non-edible plant oil and one that might be potentially cheaper than biodiesel. The characteristics of No. 6 oil, such as high viscosity at ambient temperature, which requires it to be kept heated, make the blending with such oils feasible. Jatropha oil is one such oil and there is currently considerable interest building up in its use as a source for making biodiesel and jet fuel. A 10% blend of Jatropha oil with heating oil was burned using a standard burner in a residential boiler. Combustion performance was shown to be comparable with that of burning heating oil by itself with some noticeable differences. Typical heating oil has about 2000 ppm of sulfur, while the Jatropha oil has about 50 ppm leading to lower levels of sulphur dioxide emissions. Stack measurements also showed that the NOx emission was lower with the blend. We have previously reported similar reductions in NOx with blends of biodiesel in heating oil as well as slight reductions in PM2.5, particulates below 2.5 microns in size. Long term tests were not part of this project and hence deleterious effects on pumps, seals etc., if any, were not measured. The majority of the work involved testing blends of Jatropha oil with residual oil in a 1.5 million Btu/hr boiler with a burner modified to burn residual oil. Blends of 20 and 60% Jatropha oil and 100% Jatropha oil were burned in the combustion performance tests. The residual oil used had a sulfur content of over 2000 ppm and hence dramatic reductions in sulfur dioxide emissions are measured with the blends. Again, consistent with our past experience with biodiesel blends, significant reductions in nitrogen oxide emissions nearing 50% with 100% Jatropha oil, were also measured. This is in contrast with the use of biodiesel in diesel engines, where the NOx has a tendency to increase. In addition to the gaseous emission measurements, particulate emissions were measured using an EPA CTM-39 system to obtain both particulates, of sizes below 2.5 microns, so-called PM2.5, and of sizes larger than 2.5 microns. The results show that the particulate emissions are lower with the blending of Jatropha oil. Overall, one can conclude that the blending of Jatropha oil with residual oil is a feasible approach to using non-edible plant oil to provide a renewable content to residual oil, with significant benefits in the reduction of pollutant emissions such as sulfur dioxide, nitrogen oxides and particulates.