• silicosis
• lung cancer
• mortality
• permissible exposure limit

• HRCT, high resolution computed tomography
• IARC, International Agency for Research on Cancer
• ILO, International Labour Office
• PEL, permissible exposure limit
• REL, recommended exposure limit
• TWA, time weighted average

Silicosis (Latin, silex, flint) is perhaps the oldest occupational disease, probably existing in the paleolithic period. Hippocrates and Pliny refer to the disorder. Some of the most tragic and wanton examples of occupational disease were due to silicosis, for example, how table blade grinding in Sheffield (1886) robbed workers of 25 years of life, or the Gauley Bridge disaster in West Virginia (1931). Perusing a recent standard pulmonary medicine textbook would suggest that simple silicosis is no longer a problem as it is “not associated with impairment or disability and even without effect on longevity in many although not all”.¹ Case closed, the silicosis story is over, or is it?

In this issue of Occupational and Environmental Medicine, t’ Mannetje and co-workers answer this question with an elegant and resounding “no”!² In a carefully designed pooled analysis a clear exposure-response relation for silicosis and mortality is shown. Increased mortality is also seen at exposure levels below the current US Occupational Health and Safety Administration’s permissible exposure limit (PEL) of 0.10 mg/m³ for respirable crystalline silica. This conclusion is the culmination of considerable new knowledge concerning dose-response relations and methodological developments in the past few decades. New knowledge has accumulated concerning associations between silica exposure and …