It is well understood that weaknesses in process safety management can lead to major accidents with the potential for catastrophic consequences. These weaknesses typically develop overtime due to the cumulative effect of changes in the integrity of equipment and the quality of operating practice. Such changes often go unchallenged and uncorrected as a result of complacency and what has been referred to as the normalization of deviation. Combating the slow decline and drift into failure requires the establishment of a more effective culture of process safety management. The crucial element of this culture is the identification of safety critical tasks that are essential to the maintenance and assurance of technical safety barriers.
In all hazardous systems, people are responsible for the maintenance, calibration and testing of process safety control or barrier measures. Comprehensively identifying these safety critical tasks and defining the organizational management processes that are necessary to assure their successful completion, lays the foundation for a culture of effective process safety management. It also creates the opportunity to establish leading indications of process safety and avoid relying on lagging indications which only signal the failure to control risk.
This paper presents examples of how human and organizational failures can contribute to a gradual drift into failure resulting in major accident events. It then shows how the human role in maintaining and assuring the reliability of built-in safety measures can be assessed and verified for both new assets and mature operations. The methodology demonstrated is an integrated approach to process safety and human factors and shows how the approach can be applied to create leading indications of effective process safety management that delivers both technical safety and an improved safety culture.