Cybersecurity Consideration in Process Hazard Analysis

Abstract

Traditional process hazard analysis (PHA), such as Hazard and Operability (HAZOP) studies, typically includes a systematic assessment of initiating events and consequences affecting process facilities. Relationships among initiating events, safeguards, and consequences are evaluated in depth, but such evaluation is generally based on unintentional causes such as human error or some unexpected failure of equipment, instrumentation, controls, or safeguards. As the process industry evolves toward greater reliance on and integration with information technology, it is critical to also consider malicious and intentional disruption of process operations by parties who exploit the enhanced capabilities and integration of modern communication with process controls and operations. This paper discusses the significance of considering cybersecurity threats during a PHA/HAZOP. A step-by-step and systematic technique is presented to show how a PHA team could assess the vulnerability of a system or facility to potential cyber threats, analyze adequacy of safeguards, and develop necessary countermeasures to resist cyberattacks. A typical refinery or chemical plant can have thousands of signals that are connected to a Distributed Control System (DCS) to ensure safe and smooth process operation. This arrangement could inadvertently present multiple pathways for malicious parties to intervene by manipulating signals or disrupting communications, potentially leading to severe process hazards and consequences such as a fire, explosion and fatality. Not only does incorporating cybersecurity in a PHA/HAZOP help identify the vulnerability of your system or facility, it could also be used to prioritize limited resources to ensure critical vulnerabilities are mitigated in a timely and efficient manner. The application of this technique will be demonstrated using case examples.