Minor quantities of certain sulphur compounds can cause natural gas liquids (NGL) to fail the copper strip corrosivity test. At Esso Resources Canada Limited's Quirk Creek Gas Plant, it was found that there were periods, during high plant throughput, when NGL quality excursions were experienced. To gain control of the NGL quality and to ensure that the product could be shipped by pipeline, a program was undertaken to test various ways of treating the NGL product. In this paper, the experimental work involving slip stream testing and analysis of sulphur compound removal capacity at ambient temperatures is discussed. The resulting design of a full stream catalized zinc oxide treating unit installed to assure the NGL product meets the copper strip corrosivity test specification is described.