Several factors affect the implementation of any strategy for the phase-out of lead from gasoline.
Factors of Success Oil refineries in different countries enjoy a unique starting point with regard to the various possibilities and options they have to reduce or phase out lead from gasoline. Vehicle fleets, characterized by different average ages and turnover rates, consist of a variety of vehicles equipped with engines that may or may not use unleaded gasoline. The transition period of pioneer countries like the US and Japan was much longer due to the long term research studies carried out on the risks to human health and the environment, and so the countries of Central and Eastern Europe can effectively speed this process based on the results already experienced elsewhere.