History

Why was lead added to petrol?

Petrol needs a certain octane level to prevent the engine from "pinging" or "knocking". Engine knock is caused by the uncontrolled detonation of the last part of the air-fuel mixture in the combustion chamber and may damage the engine. The octane rating of a fuel is a measure of its resistance to knock - the higher the rating, the less will be the tendency of a fuel to cause knock. Adding lead compounds to petrol was the most cost-effective way of boosting its octane rating.

Why was lead removed from petrol?

Lead was widely used as a petrol additive since the 1920's. However, leaded petrol cannot be used by cars equipped with catalytic converters designed to reduce harmful exhaust emissions, as lead very rapidly and permanently renders the catalyst completely ineffective. This, together with the realization that lead emitted from vehicle exhausts has the potential to adversely affect human health, resulted in it being phased out, first in North America and then across Europe and, increasingly, the rest of the world.

From what date was there no longer lead in petrol in South Africa?

Unleaded petrol was first introduced into the South African market in 1996. Since that date, the use of unleaded petrol has gradually increased and now accounts for approximately 40% of total petrol sales in South Africa. As from 1 January 2006, lead was no longer added to petrol in the production process and leaded petrol was no longer be marketed by the oil companies. Engen supported this move towards a lead-free environment.