The Mobil Refinery and Lube Oil Blending Plant at Notre Dame de Gravenchon, France is immediately adjacent to the mouth of the Seine River and its environmentally sensitive estuaries. All the processes and equipment in this facility must operate in a mode that is uncompromising with regard to any environmental impact. Most of the additives present no direct hazard as provided, however, some of them are seriously damaged when overheated-the worst consequence being an exothermic reaction with gas released into the atmosphere, resulting in both a safety hazard and environmental effects. Electric heat tracing and the control system operate to insure the temperatures of the process pipes, equipment, and vessels are maintained within very close tolerances. Maintaining the process temperature is an integral part of the operation that ensures viscosity and other process parameters that ultimately determine the quality of the lube oils produced.