The Human and Organizational Factors Committee (HOFCOM) of the Energy Institute (EI) are developing new guidance on ensuring safe staffing levels. The objective is to provide clear and concise guidance to help companies in the petro-chemical and allied industries to determine appropriate staffing levels. This guide builds on the Energy Institute’s “Briefing Note 23 on Workload and Staffing levels”. The guidance addresses both normal operations and emergency response as well as different stages of the operational lifecycle (commissioning, steady state operations and decommissioning). It also accounts for factors that impact upon staffing levels, such as competence, supervision, and scheduling. This publication is directed towards those responsible for determining the approach to assessing staffing levels such as human resources, maintenance and operations leads, project managers and planners, as well as safety and regulatory persons.