The accident investigation itself requires investigators to comprehend human errors, risk management at workplaces, International Safety Management (ISM) code at organizations, and utilize them for accident analysis among other things. This chapter focuses on human error, risk management and ISM Code as facilitation to extensively find out both local workplace and organizational factors. Safety management system and ISM Code are developed by ISO series, part of which is the quality management system, and are the productions of history of self-regulation. In the UK, legislative bodies had established legislation on health and safety in detail, and the regulatory body had made individuals and organizations comply with the enacted rules by legal grounds in the first half of 20th century. The fire case implies the importance of improving safety using the Plan-Do-Check-Act (PDCA) cycle. The core of the quality management system is represented by the PDCA cycle.