ct”). Another advantage to increasing the oxygenate levels in gasoline seems to be that they improves octane levels, but this is still being studied.When tetra ethyl lead (TEL) was first introduced into gasoline during the 1920’s, it became the most cost-effective way to enhance octane while reducing engine knock. This led to major gains in engine efficiency and lower gas prices, which pleased the nation. The toxicity of TEL was apparent from the outset, but people were willing to accept the trade off for cheap, efficient fuel. Up until the late 1960’s, these leads were added to gasoline in increasing concentrations to obtain greater and greater octane. By then, the toxicity of the emissions from gasoline-powered engines was becoming of increasing concern and there was a frantic search begun for an exhaust catalyst that was lead-tolerant. When nothing practical could be found, lead was on its way out as a gasoline additive. The catalytic converters used today are extremely sensitive to lead and thus the gasoline formula had to be radically changed to exclude lead. This has had a very positive effect on the environment by reducing the aggregate emission of lead by more than 95%! The known long term effects of chronic exposure to lead in humans results in damage to blood, central nervous system (CNS), blood pressure, kidneys, reproductive systems, and Vitamin D metabolism. Children are particularly sensitive to the chronic effects of lead, with slowed physical and cognitive development and reduced growth especially affected. The largest source of lead in our atmosphere had been from leaded gasoline combustion, but with the phase-out of this lead source, air lead levels have decreased considerably. This is good because lead has been shown to bioaccumulate in the environment and continues to pollute. With the removal of lead and the immediate introduction of exhaust catalysts and sophisticated engine managemen...
