that lead in petrol was contributing at least 70% to the lead intake of a 2-year-old child in Western society. This contrasted with the Government's figure of 10 per cent as outlined in the Lawther Report which had ignored the contamination of above-ground crops by airborne lead. Other key chapters were provided by Herbert Needleman from Harvard University (Chapter 12) and Clair Patterson from the California Institute of Technology (Chapter 2). In 1979, Professor Needleman had published a seminal paper in the New England Journal of Medicine that demonstrated dose-dependent relationships between elevated levels of lead in shed milk teeth and a host of negative outcomes in children, including distractibility, hyperactivity lower IQ and a tendency to get easily frustrated. Clair Patterson had built an ultra-clean laboratory in the early fifties in order to measure the minuscule quantities of lead isotopes in an iron meteorite from the birth of the solar system; by which means he was able to date the age of the Earth at 4.55 billion years, an estimate that has never been superseded. Using his ultraclean facility, Patterson was able to demonstrate that natural levels of lead in prehistoric and pristine samples were orders of magnitude lower than official estimates, most of which were measuring lead contamination. His key contribution was his “measles diagram” demonstrating that if the lead burden of a pre-technological human was represented by one dot, and a patient with clinical lead poisoning was represented by 2000 dots, then the lead burden of a typical adult living in Western society was represented by 500 dots. For no other toxin was there such a narrow gap between what is known to be typical and what is known to be toxic. However, the reason that the conference created headlines was because Professor Rutter, who had sat on the Lawther Committee, changed his mind about the causality of lead, and its association with lower IQ in children. References Environmental organisations based in the United Kingdom 1981 establishments in the United Kingdom Lead poisoning Environmental organizations established in 1981 Air pollution in the United Kingdom