Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death worldwide.¹ In the UK, COPD is given as the cause of death on about 30 000 death certificates annually.² This represents 5.1% of all deaths. The prevalence of COPD is difficult to determine because the condition does not usually manifest until mid-life, when it is already moderately advanced. In England and Wales, it is estimated that there are currently 900 000 diagnosed cases, and allowing for under-diagnosis the true prevalence is estimated to be 1.5 million.³ The total annual cost to the National Health Service for the treatment of COPD is thought to be £491 652 000 in direct costs, and £982 000 000 including indirect costs, causing 21.9 million working days to be lost in 1994–95 as a result of this condition.

A recent clinical study from the UK noted that in a random sample of COPD patients, 44% were below retirement age, and 24% reported that they were completely prevented from working by their disease.⁴ A further 9% were limited in their ability to work, and patient carers also missed time from work. Established disease clearly interferes with work capability.

Cigarette smoking is undoubtedly the main cause of COPD in the population, but the link between harmful workplace exposures and COPD has been debated for many decades. Indeed, awareness of a link between work in dusty trades and chronic bronchitis (termed industrial bronchitis⁵) can be traced back to the 19th century. In 1984, the US Surgeon General’s report concluded that the only accepted cause of COPD was tobacco smoke; occupational exposures were characterised as putative rather than established causes.⁶ Since 1993 British coalminers with chronic bronchitis and emphysema (COPD) have been eligible for compensation if …