Often companies in the (petro-) chemical industry claim that all possible countermeasures against potential accidents have been taken and therefore accidents are unforeseeable. In this paper we question this statement by analysing the pre-warning signals (precursors) preceding a number of industrial accidents. 17 accidents that occurred in the (petro-) chemical industry have been investigated by exploring FACTS, an accident database containing information about industrial accidents worldwide. This paper will demonstrate that the existence of precursor information could have been used to foresee and even prevent these accidents if a proper control action had been initiated. The accidents are analysed further, according to a control model, which was adapted from that of C. Argyris. It demonstrates the ineffectiveness of several elements of business process control loops and that the so-called ‘double-loop learning’ cycle is more important than the ‘single-loop learning’ cycle if one considers safety improvement. Copyright © 2003 John Wiley & Sons, Ltd.