The Institute of Occupational Medicine (IOM) was founded in 1969 by the National Coal Board (NCB) as an independent charity in the UK and retains this charitable purpose and status today. The "Institute" has a subsidiary, IOM Consulting Limited, which became fully independent in 1990 and now celebrates its 25th year within the IOM Group as an independent consultancy and also the commercial part of the IOM organization. It specializes in asbestos surveys and services, occupational hygiene services, nanotechnology safety, laboratory analysis and expert witness consulting services. IOM is therefore one of the UK's major independent "not for profit" centres of scientific excellence in the fields of environmental health, occupational hygiene and occupational safety. Its mission is to benefit those at work and in the community by providing quality research, consultancy, surveys, analysis and training and by maintaining an independent, impartial position as an international centre of excellence. Coal and pneumoconiosis The IOM was set up by Dr John Rogan, the chief medical officer of the NCB, who had initiated the Pneumoconiosis Field Research (PFR), persuaded the then chairman, Lord Robens, to found a scientific institute to take over the running of this research. The original senior members of staff, under Rogan, were Henry Walton, deputy director and head of Environment Branch, Dr Michael Jacobsen, head of statistics and Dr David Muir, head of Medical Branch. The early history of the IOM is inextricably bound up with the NCB and the PFR. The PFR had started in the early 1950s with the objective of determining how much and what types of coal dust caused pneumoconiosis and what airborne dust concentrations should be maintained in order to prevent miners from becoming disabled by the air they breathed. These ambitious and clear objectives were remarkably far-sighted, implying a requirement to measure both exposure to airborne dust and health outcomes in a large cohort of miners over a prolonged period, and to use these quantitative data to set protective health standards in the industry. 50,000 coalminers were eventually recruited into the study from 25 collieries representative of conditions across Britain. The early work involved measuring dust exposure by counting the number of particles collected from the air by sampling devices. A substantial advance was achieved with the measurement of exposure by weighing the dust collected by MRE 113a respirable dust samplers, which were invented specifically for the research by Henry Walton and Robert