The Swiss cheese model (SCM) has unsolved issues, and this chapter discusses those issues while illustrating the location of holes and latent conditions with a new accident model that was developed by the Late 1 SCM. The accident model is divided into three categories: Sequential accident models, systemic accident models, and epidemiological accident models. The systemic accident model is represented by the functional resonance accident model, which rejects cause-effect links and regards the accident as an emergent phenomenon. In the context of the SCM, potential accidents and losses can be avoided by preventing holes from lining up. According to the SCM, a number of defensive layers and associated holes exist between hazards and potential losses. These holes are in continuous motion, moving from one place to another, and opening and shutting. The most frequent hole in the defensive layer of risk management was not necessarily the same for different types of accidents.