petrol

Mixture of hydrocarbons derived from petroleum, mainly used as a fuel for internal-combustion engines. It is colourless and highly volatile. Leaded petrol contains antiknock (a mixture of tetra ethyl lead and dibromoethane), which improves the combustion of petrol and the performance of a car engine. The lead from the exhaust fumes enters the atmosphere, mostly as simple lead compounds. There is strong evidence that it can act as a nerve poison on young children and cause mental impairment. This prompted a gradual switch to the use of unleaded petrol in the UK.

The changeover from leaded petrol gained momentum from 1989 owing to a change in the tax on petrol, making it cheaper to buy unleaded fuel. Unleaded petrol contains a different mixture of hydrocarbons from leaded petrol. Leaded petrol cannot be used in cars fitted with a catalytic converter.

In the USA, petrol is called gasoline, and unleaded petrol has been used for many years.

In 1998 US petrol prices were the lowest in recorded history with inflation taken into account, the US Energy Secretary Federico Pena announced in April. The average US price for unleaded petrol in early April was $1.03, down 10 cents from 1997.