Plant-wide NOx emission reduction projects which today seem increasingly to be required or, at least, talked about by local jurisdictions internationally can severely threaten the profitability of process plants or, at least, are sometimes seen to threaten the profitability of process plants by those plant owners who have never done such a project and are therefore unfamiliar with them. When a plant-wide emissions reduction project is imposed by regulatory authorities, plant owners are naturally keen to know what to do about it. However, the last thing some plant owners want to hear is that the first step is to get rid of cheap fuel firing. From time to time I am contacted by sales promoters or plant owners generally not in places like California or Texas where many plant-wide emission reduction projects have been carried out, but in developing economies, wondering about "heavy oil firing" or the like. They either want to sell or fire heavy oil for process heating. But they don't want to hear the truth; viz., that the very first thing to do is to get rid of heavy oil firing when it comes to controlling NOx emissions. At Chevron, we learned that lesson the hard way but learned it well, saving the shareholders lots of money and in the process gaining extensive experience particularly in regulator-imposed retrofits of refineries in California.