Lifecycle of Accident Pathogens: Common Systemic Factors in Construction System Accidents

Construction system accidents are accidents due to defects embedded in the constructed systems (e.g., buildings, bridges, and other infrastructures) originating from failures in construction systems, which we can consider as organic and ephemeral temporary multi-organizations (TMOs). Understanding the mechanisms of such accidents in transient and multi-organizational systems requires a system-wide perspective and consideration of the temporary aspect. This paper examines six accident cases using the framed-and-layered accident pathogen propagation (FLAPP) model—-an accident model we specifically developed to capture system-wide factors and the time dimension—-and identifies five types of pathogen threads and eight types of thread elements that contribute to the propagation of latent failures and defects, i.e., accident pathogens. With concrete reference to the processes and products found in accident cases, the concept of pathogen thread provides an explicit structure to the classic metaphor of pathogens that the safety literature has been using to describe latent failures. This paper further proposes the concepts of pathogen susceptibility and transmissibility to explain the mechanisms and dynamics that drive the generation and propagation of accident pathogens. Acknowledging the limitations of the modeling framework, this paper concludes with a discussion of lessons for systems engineering practices and directions for future work to ensure system safety in the construction of systems in various domains.