Last week the US Chemical Safety Board published its review of the fatal explosion at BP's Texas City oil refinery. The board criticised senior executives of the company for demanding cost reductions at the expense of safety. Chemical plants are, by their nature, full of flammable liquids. Airlines carry their customers in fragile metal boxes at speed and altitude. Pharmaceutical products are effective only because they interfere with our bodies.

Refineries, aircraft and drugs are inherently dangerous. There is no limit to what can be spent to make them safer. But if there were no limit to spending, oil, flying and pharmacology would be prohibitively expensive. To say that safety must always come first, as we are all inclined to do when we hear of a tragic accident, is to indulge in empty rhetoric. It is to ignore the real social, ethical and commercial dilemmas that conscientious commentators, regulators and business people face.