There is increasing worldwide interest in diesel particulate filters (DPF) because of their proven effectiveness in reducing exhaust smoke and particulate emissions. Fine particulates have been liked to human health. DPF use requires a means to secure the burn-out of the accumulated soot, a process called regeneration. If this is not achieved, the engine cannot continue to operate. A number of techniques are available, but most are complex, expensive or have a high electrical demand. The use of fuel additives to catalyze soot burn-out potentially solves the problem of securing regeneration reliably and at low cost.Work on organo-metallic fuel additives has shown that certain metals combine to give exceptional regeneration performance. Best performance was achieved with a combination of iron and strontium-based compounds. Tests were carried out on a bed engine and on road vehicles, which demonstrated effective and reliable regeneration from a low dose fuel additive, using a single passive DPF. No control valves, flow diverters, heaters or other devices were employed to assist regeneration. Independent particle size measurements showed that there were no harmful side effects from the use of the iron-strontium fuel additive.