Thermal reactor systems have been designed to assist in the development of a low emission concept vehicle to meet exhaust emission goals of 0.82 gm/mile hydrocarbon, 7.1 gm/mile carbon monoxide, and 0.68 gm/mile nitrogen oxides established by the Inter-Industry Emission Control (IIEC) Program. The reactor includes design features required for acceptable life characteristics, together with the quick warm-up necessary to achieve the emission targets. Exhaust gas recirculation and enrichened carburetion are used to reduce the oxides of nitrogen.Associated problems defined during development of several thermal reactor systems are described. The primary problem was achieving durability at the typically high operating exhaust gas temperatures (1600-1800 F) necessary for concurrent HC, CO, and NOx control.Fuel additives such as lead, halogen scavengers, phosphorus, and sulphur were studied extensively under thermal cycling engine operating conditions to determine their effects on material durability. Acceptable corrosion control of potential reactor materials will require the use of an unleaded or low-lead (0.5 gm/gal) fuel.