This study determined the critical risk factors that influence the risk of major accidents in petroleum and chemical industries. The retrospective study assessed five iconic accidents using the tripod beta analysis methodology. These failures were aggregated into critical risk factors for these major accidents. The findings of this study revealed empirically that there are broadly five critical risk factors that influence the risk of major accidents: (i) design flaws, (ii) site process safety management, (iii) barrier management / control, (iv) operating procedures, and (v) process safety culture. These findings highlight that major accident risks can accumulate “dangerous” from the impairment of safety-critical barriers and that the operators of petroleum and chemical facilities may be blind-sided to the cumulative risk of the impairments. The findings also highlight the need for a proactive risk assessment tool with the capability to check the health of safety-critical barriers on a real time basis, in an operating plant. The use of Tripod Beta as a tool in accident causation analysis is recommended
