A process safety culture maturity assessment was conducted for the specialty gas processing sector that has the following sections: Gas-to-Liquid, Effluent and Disposal, Ammonia and Steam Utilities plants. The assessment utilised human factors dimensions related to man-machine, employee job roles and organizational culture interfaces. Numerous global process safety incidents resulted in catastrophic consequences originated from human factors and have encouraged the investigation of underlying human and organizational behaviors to manage key process safety risks. The research construct used a process safety culture assessment toolkit, perception survey and interviews, hydrocarbon leak incident history with audit results to assess implementation effectiveness of process safety management systems. Leadership behaviors that hindered process safety maturity included unwillingness to accept accountability, employee blame, fear and lack of trust were associated with inadequate process safety incident reporting and organizational learning. High level human factors risks identified from the case study were additional resources required to update operating procedures, competence of critical staff and ineffective safety communication that have created process safety incidents. Four process safety maturity models were used for the research based on commitment towards continuous improvement; incident reporting effectiveness and examining interdependent team leadership behaviors through process safety balance scorecard metrics. Process safety maturity levels in decreasing order were Gas-to-Liquid, Ammonia, Effluent and Disposal, and Steam Utilities plants. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.