This document defines key terms related to occupational health, safety and welfare. It discusses health as protecting workers from illness caused by workplace materials, processes or procedures. Safety is defined as protecting workers from physical injury. Welfare involves providing facilities to maintain worker health and well-being. Other terms defined include occupational illness, environmental protection, accidents, near misses, dangerous occurrences, hazards, risks and more. Causes of accidents and injuries are distinguished. Reporting requirements and procedures are outlined.