New Wine in New Cups: Measuring Operator Performance for Safety-II Perspective

Standard operating procedures (SOPs) play a critical role in achieving safety and productivity of day-to-day operations in the chemical industries. Investigations of previous incidents also indicate that a majority of adverse events during routine and non-routine operations are attributed to issues associated with SOPs. For example, a recent investigation of fatalities that occurred at DuPont La Porte facility points out the absence of formal procedure required to remove plugging (e.g., hydrate) from a waste gas piping system and inadequate emergency procedures for hazard notification and evacuation as major causes of the incident [1]. To ensure the safety of a complex system such as chemical plants, there have been two viewpoints towards human operators’ use of SOPs: Safety-I and Safety-II. First, Safety-I perspective defines safety as the absence of undesired events [2]. Thus, it looks for things that went wrong (e.g., slip, mistake, violation) and seeks to minimize the deviations from prescribed tasks, which is assumed to be a cause of adverse incidents . Second, Safety-II views safety as the presence of desirable and successful outcomes. Therefore, this standpoint highlights things that went right (e.g., adaptive behavior, workaround), and considers performance variability of human operators from SOPs to be inevitable and even necessary to maintain safe operations of the system [3]. In favor of Safety-I approach, conventional measures of SOP performance have long been established and utilized to indicate the degree of safety in relations to procedural systems. Nonetheless, no measures of human operators’ SOP performance that adopt or support Safety-II framework exist to date. To address such a gap, this paper identifies limitations of traditional and dominant measures of SOP performance and then proposes a novel idea that harmonizes the two views towards safety (i.e., Safety-I and Safety-II). The new measurement concept embraces not only the conventional measures regarding the implementation of SOPs (i.e., following or not following a procedure), but also incorporates human adaptive behaviors. To instantiate the new measures of SOP performance, case studies using real-world examples in the chemical industries are presented. Following this, implications for the proposed measure of SOP performance based on Safety-II viewpoint and future research proposals to support the benefits of the measure are provided.

References

1. U.S. Chemical Safety Board, Investigation Report: Toxic Chemical Release at the DuPont La Porte Chemical Facility. 2019.
2. Hollnagel, E., Safety-I and Safety–II: The Past and Future of Safety Management. 2014, Surrey, UK: Ashgate Publishing.
3. Sujan, M.A., H. Huang, and J. Braithwaite, Learning from incidents in health care: Critique from a Safety-II perspective. Safety Science, 2017. 99: p. 115-121.