Everyone makes mistakes. Therefore, every Process Hazards Analysis should address the potential for error when humans interact with a processing system. It is unreasonable, however, to ask a PHA team to address every error that could be made by a person, so guidance must be given on the types of human factors to address.

Slips, mistakes and violations are all types of human factors that could result in a hazardous scenario, or prevent a protection layer from working correctly during a critical hazardous scenario. A PHA must consider human error in the identification of causes and in assigning safeguards or protection layers, but this must be done in a way that keeps the quality and efficiency of the PHA session at a high level.

To effectively incorporate human factors into PHAs it is essential to understand why people take these incorrect actions. Once this is understood it is possible to address them effectively, improving the identification of potential causes of hazardous scenarios and the PHA team’s ability to validate safeguards that require a human response.

This paper will investigate the types of errors and violations people make, and discuss the reasons that people act in this way. It will then explain how to effectively incorporate this knowledge into a plan for addressing human factors in PHAs when identifying potential causes of hazardous scenarios and in deciding which protection layers to rely on. To achieve this, it will reference existing literature and draw on the author’s experience of facilitating over 200 PHAs for a wide variety of petrochemicals and hazardous materials processing companies throughout North America.