§ Mr. Salmond
To ask the Secretary of State for the Environment what analyses of the safety, or impact on human health, of unleaded petrol have been carried out; if he will give details; and if he will make a statement.392W
§ Mr. Maclean
The hon. Member may have in mind the fact that the benzene content of unleaded petrol in the United Kingdom is typically rather higher, at 3 to 4 per cent., than for leaded petrol—2.5 per cent. Benzene is a genotoxic carcinogen. A number of studies have been made of the effects of occupational exposure to benzene, and the Department's expert panel on air quality standards has been asked to make recommendations on an ambient air quality standard for benzene. However, the major source of benzene emissions in the United Kingdom is not the evaporation of petrol but rather petrol engine exhaust, and most of the benzene in this exhaust arises from the "cracking" of aromatics in the engine rather than from the original benzene content of the fuel. Harmful exhaust emissions, including benzene, can be drastically reduced by fitting three-way catalytic converters to cars. This will be mandatory under EC standards for new cars from the end of 1992. Cars with catalytic converters will run only on unleaded petrol.