Used oils are a dangerous waste product whose inadequate management can damage the environment. At the same time, they have an undisputable economic value in that they maintain a very significant part of the hydrocarbons that lubricating oils originally contain. The collection of used oils is the necessary condition for sound management. The collection rate in Spain has varied significantly in recent decades, from levels under 20%, at the beginning of the sixties, to over 70% at the end of the nineties. Against this background, we analyse the used oil market in Spain during the period 1965-1999, estimating supply and demand functions. The objective is to identify the factors determining the development of the market and to evaluate the effectiveness of policy measures that promote collection.

Key words: used oils, waste, recycling, public policies.
JEL classification: L71, Q31, Q38.